# 2002A Gemini North Queue Abstracts

Abstracts for all successful 2002A queue programs on Gemini North are given below.

GN-2002A-Q-1

Title: The Lyman Alpha Forest and the Galaxy Distribution towards PG 1634+706

Abstract: We propose to carry out a deep galaxy survey towards the bright, intermediate-redshift quasar PG 1634+706 (V=14.9, z_em=1.334). We have obtained a high signal-to-noise echelle spectrum of PG 1634+706 with HST/STIS, in order to study the Ly$\alpha$ forest and metal absorbers in detail. The galaxy survey with Gemini/GMOS will allow us to (1) identify the galaxies giving rise to several complex CIV/MgII/OVI absorption line systems at $z=0.3-1.0$ and (2) map the galaxy distribution so that we can look for correlations between large scale structures and the clusters of weak Lyman forest clouds we see in the UV spectrum. PG 1634+706 is the first of 4 intermediate redshift quasars we are observing with the STIS echelle, in the first comprehensive survey at echelle resolution of quasar absorbers at redshifts $z=0.5-2$. Our survey bridges the gap between the $z=2-6$ absorbers observed from the ground, and the $z<0.3$ low redshift systems previously studied with HST and FUSE. The redshift range $z=0.5-2$ is of great interest, since it is marks the peak of star-formation and quasar activity, and is the time during which galaxies formed into the mature Hubble sequence we see today.

GN-2002A-Q-2

Title: The Lyman Alpha Forest and the Galaxy Distribution towards PG 1634+706

Abstract: We propose to carry out a deep galaxy survey towards the bright, intermediate-redshift quasar PG 1634+706 (V=14.9, $z_{em}=1.334$). We have obtained a high signal-to-noise echelle spectrum of PG 1634+706 with HST/STIS, in order to study the Ly$\alpha$ forest and metal absorbers in detail. The galaxy survey with Gemini/GMOS will allow us to (1) identify the galaxies giving rise to several complex CIV/MgII/OVI absorption line systems at $z=0.3-1.0$ and (2) map the galaxy distribution so that we can look for correlations between large scale structures and the clusters of weak Lyman forest clouds we see in the UV spectrum. PG 1634+706 is the first of 4 intermediate redshift quasars we are observing with the STIS echelle, in the first comprehensive survey at echelle resolution of quasar absorbers at redshifts $z=0.5-2$. Our survey bridges the gap between the $z=2-6$ absorbers observed from the ground, and the $z<0.3$ low redshift systems previously studied with HST and FUSE. The redshift range $z=0.5-2$ is of great interest, since it is marks the peak of star-formation and quasar activity, and is the time during which galaxies formed into the mature Hubble sequence we see today.

GN-2002A-Q-3

Title: Very Cool White Dwarf Stars: Constraints to the Chemical Evolution Models and Theories of Non-Ideal Gases

Abstract: We propose to use the NIRI on the Gemini to obtain near-infrared spectra of a selected sample of cool WDs to reveal for the first time the 1 -- 2.5 micron spectral properties of these stellar remnants. Our sample comprises four very cool (Teff 2500--5000 K) WDs; one of them suspected to be a binary system. Such a comprehensive study has not been possible before due to the relatively faint magnitudes of these objects (i.e., V 23 -- 19 vs. K 18 -- 15). NIRI spectra will allow us to detect molecular H bands in the spectra of these objects and thus obtain definitive evidences of the presence of H in their atmospheres. These observations will place better constraints on the chemical evolution and provide support to recent theoretical calculations that predict that very cool low mass (He-core) WDs should have H-pure atmospheres. In addition these data will provide new constraints to the opacity in the near-infrared wavelengths and to the physics of non-ideal gases. We expect these observations will greatly contribute to improve our knowledge of these objects, in particular the current chemical evolution models and the physics processes of non-ideal gases. Note: This proposal was ranked in Band I (2001A, semester). The observations were not taken either because of NIRI technical problems or because Argentina lost the corresponding observing semester.

GN-2002A-Q-4

Title: A Near Infrared Investigation of Optically Obscured Galactic

Abstract: We propose to continue our survey of giant HII regions at $JHK$. Our eventual goals are to characterize their stellar content, investigate the nature of massive star formation, and to use the derived infrared spectral types to determine distances and as probes of Galactic structure. The infrared photometry will be used to identify massive star and young stellar object candidates for follow--up spectroscopy (on both 4m and 8m class telescopes). Our program and other recent near infrared observations are producing examples of clusters of newly born massive stars. We have already identified O stars and massive YSOs in a number of GHII regions and will continue our succesful survey in other GHII regions using 4m imaging for new clusters and 4m spectroscopy for clusters for which we already have imaging data. Further, we will use Gemini to go farther down the main sequence spectroscopically in W31 producing a more accurate mass, age, and luminosity for this rich young cluster.

GN-2002A-Q-5

Title: A Near-IR study of optically ambiguous Seyferts: Implications for the Starburst-AGN connection

Abstract: Optical-UV studies have established the existence of a "starburst-AGN connection" in Seyfert 2 galaxies (Sy2), a connection which is believed to extend to the epoch of formation of bulges and ellipticals. Near IR (NIR) spectroscopy offers a unique opportunity of tackle this issue more closely, with the advantages of overcoming the severe difficulties in the optical--UV detection of starbursts in Seyferts, while simultaneously probing deeper into dusty regions and providing reliable stellar population diagnostics. We propose a NIR study of Sy2's selected because of their ambiguous optical properties. They all show a strong featureless continuum'' which, unlike for {\it bona fide} composite starburst+Sy2 galaxies, cannot be unambiguously attributed to young stars because of the limitations of optical diagnostics. As many as 1/3 of Sy2's belong to this ambiguous and poorly understood category. The NIR data will allow us to break this degeneracy'' by determining whether or not they contain starbursts. This will help us figure how this sizeable portion of the Sy2 population fits into the emerging scenario for the starburst-AGN connection.

GN-2002A-Q-6

Title: Direct imaging of very low mass companions and binary brown dwarfs

Abstract: {\bf RESULTS TO DATE:} In 2 nights in 2001A and 0.5 nights in 1999B we have now detected 6 new brown dwarf binaries out of 31 systems imaged (compared to the 8 known before this survey -Close et al 2001). The discovery of these new brown dwarf binaries will establish the all important mass-luminosity-age relation for substellar objects once their orbits are observed. This is also the first step to the determination of the luminosity of exo-solar planets. Moreover, we have detected at least 4 extra-solar planetary candidates with masses from 4-10 Jupiters {\it if they prove to be common proper motion pairs}. Here we request another 2 nights (and 0.5 nights of followup) in 2002A as we did in 2001B. These nights will be used to finish this highly successful survey and to confirm or disprove if any of our planetary candidates are physical. We are very excited about the success of this survey and look forward to its successful completion in 2002A.\\ {\bf PROPOSAL:} We propose to continue to utilize Gemini and Hokupa'a to search for very low mass (2-60 jupiter mass) companions around newly discovered low luminosity (M6.5 or later) nearby ($D<25pc$) stars. We propose to observe the remaining 50 objects from our candidate list in 2 nights (Run 1) with one more half night (Run 2) $\sim 3$ months later to confirm which of the detected companions are physical (e.g common proper motion pairs). This is the first survey to probe these planetary masses in the critical formation zone (5-15 AU) where such massive planets are commonly thought to form.

GN-2002A-Q-7

Title: Direct imaging of very low mass companions and binary brown dwarfs

Abstract: {\bf RESULTS TO DATE:} In 2 nights in 2001A and 0.5 nights in 1999B we have now detected 6 new brown dwarf binaries out of 31 systems imaged (compared to the 8 known before this survey -Close et al 2001). The discovery of these new brown dwarf binaries will establish the all important mass-luminosity-age relation for substellar objects once their orbits are observed. This is also the first step to the determination of the luminosity of exo-solar planets. Morover, we have detected at least 4 extra-solar planetary candiadates with mases from 4-10 Jupiters {\it if they prove to be common proper motion pairs}. Here we request another 2 nights (and 0.5 nights of followup) in 2002A as we did in 2001B. These nights will be used to finish this highly successful survey and to confirm or disprove if any of our planetary candidates are physical. We are very excited about the success of this survey and look forward to its successful completion in 2002A.\\ {\bf PROPOSAL:} We propose to continue to utilize Gemini and Hokupa'a to search for very low mass (2-60 jupiter mass) companions around newly discovered low luminosity (M6.5 or later) nearby ($D<25pc$) stars. We propose to observe the remaining 50 objects from our candidate list in 2 nights (Run 1) with one more half night (Run 2) $\sim 3$ months later to confirm which of the detected companions are physical (e.g common proper motion pairs).This is the first survey to probe these planetary masses in the critical formation zone (5-15 AU) where such massive planets are commonly thought to form.

GN-2002A-Q-8

Title: SC24: the lowest metallicity star-forming galaxy in the Universe?

Abstract: We propose to obtain the chemical abundance of SC24, a dwarf Irregular galaxy recently discovered in the nearby Sculptor Group (Cote et al 1997). Through Halpha CCD imaging (observed at CTIO; Skillman, Cote, Miller 2002) we have discovered an HII region in this galaxy, making it the lowest luminosity star-forming galaxy known. Because of the strong correlation between luminosity and abundance in dwarf galaxies, we expect this galaxy to possess one of the most (possibly the most!) primitive chemical environment known, ideal for studying the early stages of nucleosynthesis in galaxies.

GN-2002A-Q-9

Title: Probing the high redshift Universe via quasars with z>5

Abstract: GMOS will be used to obtain identification spectra of redshift 5-7 quasars for a project whose ultimate goals are: (1) To establish the contribution of AGN to the integrated extragalactic ultraviolet background light at the highest possible redshifts. (2) To establish unambiguously the rate of decline in the space density of quasars out to a redshift of about 6.5 ; (3) To determine the epoch of reionization via the Gunn-Peterson test; (4) To identify a sample of z>5 damped Lyman alpha absorbers The QSO candidates have been selected from our recent deep imaging survey at CFHT, which goes more than two magnitudes fainter than the Sloan survey. The success of our selection method is demonstrated by our rediscovery of a SDSS QSO in one of our fields at z=4.99. This, combined with the recent success of GMOS commissioning, gives us confidence to expand the survey. By adding the proposed observations to those scheduled in 2001B we will complete one survey field, an area of 1.8sq deg, in which we expect to find 8-9 z>5 QSOs.

GN-2002A-Q-10

Title: The Extended Star Formation Histories of the M81 Group dwarf Ellipticals F8D1 and BK 5N

Abstract: We propose to use NIRI to image in the J and K bands the dwarf elliptical (dE) galaxies F8D1 and BK 5N. These dwarfs are members of the M81 group, one of the nearest groups beyond the Local Group. Our HST/WFPC2 study (in the V and I bands; Caldwell et al., 1998, AJ, 115, 535) has revealed the presence of significant numbers of stars above the tip of the red giant branch in both galaxies, an indication of the presence of an intermediate-age (~2 < age < ~10 Gyr) population. Near-IR band photometry is required, however, to determine bolometric magnitudes for these upper-AGB stars, and thus provide improved estimates of their ages. Our results will provide information on the extended epochs of star formation in these dwarf ellipticals which will be directly comparable to existing information for Local Group dEs, such as the dwarf spheroidal companions to the Galaxy and to M31. In this way we will add to the understanding of the factors, including environment, that govern the star formation history in these allegedly simple galaxies. (This proposal is currently in the second scientific ranking band for execution in semester 2001B. This resubmission for 2002A time is in case the program is not carried out in semester 2001B. If the program is executed successfully in 2001B, no 2002A time is required).

GN-2002A-Q-11

Title: The structure of nova shells

Abstract: The project described in this contribution aims to study the structure of nova shells and their ionizing sources. This question will be addressed by improved physical and chemical diagnostics derived from spatially resolved spectroscopic and photometric observations. New model constraints can be obtained using observations of the nebular continuum, dust emission and infrared coronal lines. These data will be analyzed together with the optical diagnostic lines sampled along the evolution of the nova ejecta.

GN-2002A-Q-12

Title: The dust-enshrouded formation of massive elliptical galaxies

Abstract: We re-propose deep NIRI K-band imaging of 8 of the brightest sub-mm sources (S_{850} > 8 mJy) from our major SCUBA/JCMT surveys. These sources have inferred dust-enshrouded star-formation rates >1000 solar masses/yr, as required for the formation of massive elliptical galaxies in ~ 1 Gyr, and are sufficiently numerous to potentially account for the formation of all present-day massive (>4L*) ellipticals. Determining their nature/redshifts is now of fundamental importance for understanding galaxy/structure formation. Finding unambiguous IDs requires high-accuracy positions (which we now possess from deep VLA and IRAM PdB observations) combined with very deep infrared imaging. Our one existing deep (5 hrs with UKIRT) K-band identification has K=21-22, and a complex morphology reminiscent of radio galaxies at z=3-4, suggesting that the high-z formation epoch inferred for radio galaxies may apply to massive spheroids in general. This proposal is a resubmission of the 2nd part of the programme currently ranked top in the 01B UK Gemini queue, for targets from the originally-approved 01A programme which are unobservable in semester 01B.

GN-2002A-Q-13

Title: Multi-Object Spectroscopy of the GC Systems of Luminous Ellipticals

Abstract: We propose to use GMOS to obtain multi-object spectroscopy of globular clusters in three luminous elliptical galaxies which have bimodal globular cluster colour distributions. We will measure metallicity-sensitive and age-sensitive line-strength indices for the clusters, investigating the mechanism, epoch and timescale of their formation, thereby probing the galaxies' stellar assembly. Kinematics for the clusters will reveal the dynamics of their sub-populations, further testing competing models of cluster formation. We will obtain mass-profiles for the galaxies out to $\sim$ 22 kpc, providing one of the few direct probes of dark matter in ellipticals at large radii. Gemini-N/GMOS is unique in providing {\it large numbers} of high-quality cluster spectra, to simultaneously derive ages, metallicities $and$ kinematics for the globular clusters.

GN-2002A-Q-14

Title: CO in T-type (methane-dominated) brown dwarfs

Abstract: T-type or "methane-dominated" dwarfs are brown dwarfs whose photospheres are sufficiently cool that almost all carbon is incorporated in methane rather than in carbon monoxide. In chemical equilibrium the fraction of carbon in CH4 would be virtually 100 percent in the photospheres of objects as cool as the prototypical T dwarf, Gliese 229B. However, M-band spectra of Gl 229B show a much larger (although inaccurately known) abundance of CO than predicted for chemical equilibrium. The reason for this difference is unknown, but it is suspected that upwelling of gas from deeper and hotter layers, where CO is more abundant, is responsible. We propose to obtain M band spectra of Gl 229B, three additional T-type dwarfs and a late L dwarf, covering a wide range of effective temperatures, in order to begin to explore whether the overabundance of CO is common and how it might depend on temperature (i.e., evolutionary state). The results should begin to reveal similarities, differences, or patterns in brown dwarf atmospheric structure and evolution and could also have important implications for abundances in giant planets and their stellar primaries.

GN-2002A-Q-15

Title: Galaxy Evolution and the Micro-Jy Radio Population

Abstract: We propose deep MOS spectroscopy with GMOS of an unique sample of ultra-faint radio sources selected from some of the deepest 1.4-GHz VLA maps ever made. This sample is the basis of an on-going program to exploit sensitive radio observations as a dust-independent tracer of the evolution of star formation and AGN activity in galaxies at z=0-4. The proposed GMOS observations will provide essential confirmation of the reliability of photometric redshift techniques for faint (perhaps very dusty) radio galaxies and most importantly will allow us to gauge the proportions of AGN- and star-formation-dominated systems as a function of radio flux down to flux limits of ~15 microJy. This is crucial for attempts to derive the evolution of star formation density for this population.

GN-2002A-Q-16

Title: Rapid Variability of Subarcsecond Wisps and Knots in the Crab Nebula

Abstract: We propose to carry out near-IR, AO imaging (with Hokupa'a) of variable subarcsecond features (wisps and knots) in the termination shock of the relativistic wind of the Crab pulsar, yielding * the highest resolution near-IR images of the features to date * nine-frame movies in J and K with frames separated by 15 min and 24 hr (cf. 120 hr HST), resolving the light-crossing and ion-cyclotron time-scales of the finest features for the first time * continuum spectral indices of individual wisps and knots from J, K, and V (HST) fluxes. The data will probe the dynamics of accelerated ions in the pulsar wind, the differences between polar and equatorial wind structure and variability, and determine the physical origin (wave instability versus internal shocks) of radiation from the knots.

GN-2002A-Q-17

Title: The Ages, Metallicities, and Velocities of Globular Clusters in Virgo Dwarf Elliptical Galaxies

Abstract: We propose a pilot program to obtain GMOS spectra of globular clusters and nuclei in three Virgo dwarf elliptical galaxies with the aim of measuring line indices and radial velociities for globular clusters with V<23. We will use the spectra to break the metallicity/age degeneracy in our broad-band photometry to determine the relative ages and metallicities of the nuclei and globular clusters. In addition, radial velocities of the globulars will provide rough estimates of the velocity dispersions of the globular cluster systems that will help constrain the dark matter distribution in the dwarf galaxies. These results are needed to distinguish various theories of dwarf elliptical galaxy formation.

GN-2002A-Q-18

Title: Cosmology with High-Redshift Type Ia Supernovae

Abstract: The current Type Ia supernova Hubble diagram and CMB observations argue for a flat universe with some form of dark energy'' accelerating its expansion. Studies of distant supernovae can probe the expansion history of the universe through our current dark-energy-dominated era back to a matter-dominated era, making them one of the best current methods to study the amount and nature of such dark energy. With this program of SN studies we have an opportunity to obtain a Hubble diagram that will be of longlasting value as a record of the expansion history of the universe over the last 10 billion years. The CTIO 4-m telescope will reach back in time to find supernovae when the universe was still matter-dominated, extending our understanding of the expansion of the universe and possible evolution of supernovae over time. The Gemini GMOS will provide spectroscopic confirmation of a selection of these SNe and, together with the WIYN telescope, will allow us to obtain photometric follow-up -- and hence a measurement of the brightness of these standard candles as a function of redshift. The Gemini NIRI will allow us to obtain crucial data for the very highest-redshift ($z > 1$) supernova whose rest-frame V-band will have been redshifted to our J-band. The CTIO search triggers all of the confirmation and follow-up work requested here as well as that which we have requested at other facilities.

GN-2002A-Q-19

Title: Clustering of Galaxy Clusters at Intermediate Redshifts

Abstract: We propose to continue a redshift survey of 141 objectively selected galaxy clusters to measure their clustering properties and constrain models of the formation of structure in the universe. This is the first redshift survey to probe cluster correlations on comoving scales of $\sim 50h_{75}^{-1}$ Mpc at $z \sim 0.5$ and will thus provide an original and important constraint on the evolution of large-scale structure. The cluster sample comes from our deep (I$_{{\rm AB}} \le 24$), contiguous 16 deg$^2$ I-band KPNO 4-m survey. The proposed observations distinguish themselves from other ongoing distant cluster redshift work in that this survey will be able to provide meaningful constraints on the {\it large-scale} spatial distribution of moderate redshift clusters owing to the large angular area and contiguous geometry of the parent survey. The availability of GMOS and MARS provide a highly efficient solution to the acquisition of redshifts for the 100 cluster candidates with $0.5 < z_{est} \le 0.7$. The systems with $z_{est} > 0.6$ are needed to assure complete sampling of the cluster population at $z_{obs} \sim 0.5$. The observational strategy is extremely well-suited to the initial capabilities and queue observing mode of Gemini. Interim projects which are being executed during the course of the survey include homogeneous studies of intermediate $z$ brightest cluster galaxies, the space densities of clusters and superclusters, and cross-correlations with existing VLA 20 cm data. This survey began using the KPNO 4m to obtain redshifts for the $0.3 \le z_{est} < 0.5$ sample. We have completed this phase of the program and have observed 41 clusters. We have discovered at least 2 superclusters at $z = 0.23$ and $z = 0.50$.

GN-2002A-Q-20

Title: A search for evidence of early star formation in galaxies around the highest known redshift QSOs at z~6

Abstract: Fan et al.(astro-ph/0108063) have recently discovered 3 quasars with redshifts greater than z=5.8. The significant aspect of this discovery is the gradual appearance of a complete Gunn-Peterson trough indicative of the epoch of re-ionization of the universe. As the earliest generations of stars are expected to make a significant contribution to the re-ionization, such stars may be visible in the quasars' companion galaxies. We propose to use GMOS in long slit mode to look for Ly-alpha emission from these companion galaxies.

GN-2002A-Q-21

Title: Multi-Object Spectroscopy of the GC Systems of Luminous Ellipticals

Abstract: We propose to use GMOS to obtain multi-object spectroscopy of globular clusters in three luminous elliptical galaxies which have bimodal globular cluster colour distributions. We will measure metallicity-sensitive and age-sensitive line-strength indices for the clusters, investigating the mechanism, epoch and timescale of their formation, thereby probing the galaxies' stellar assembly. Kinematics for the clusters will reveal the dynamics of their sub-populations, further testing competing models of cluster formation. We will obtain mass-profiles for the galaxies out to ~22 kpc, providing one of the few direct probes of dark matter in ellipticals at large radii. Gemini-N/GMOS is unique in providing large numbers of high-quality cluster spectra, to simultaneously derive ages, metallicities and kinematics for the globular clusters.

GN-2002A-Q-22

Title: Galaxy Evolution and the Micro-Jy Radio Population

Abstract: We propose deep MOS spectroscopy with GMOS of an unique sample of ultra-faint radio sources selected from some of the deepest 1.4-GHz VLA maps ever made. This sample is the basis of an on-going program to exploit sensitive radio observations as a dust-independent tracer of the evolution of star formation and AGN activity in galaxies at z=0-4. The proposed GMOS observations will provide essential confirmation of the reliability of photometric redshift techniques for faint (perhaps very dusty) radio galaxies and most importantly will allow us to gauge the proportions of AGN- and star-formation-dominated systems as a function of radio flux down to flux limits of ~15 microJy. This is crucial for attempts to derive the evolution of star formation density for this population.

GN-2002A-Q-23

Title: The youngest and most luminous Giant HII regions: a link with HII galaxies

Abstract: For a very long time, HII regions have been associated with recent star formation. The brightest subset of these, also known as Giant HII regions are expected to be nesting the formation of massive stars at very large rates, hence their denomination as starburst regions.One of the outstanding properties of these regions is their supersonic observed linewidth. Furthermore this supersonic width correlates well with its linear diameter and the overall luminosity emitted in that line and this correlation seems to hold for HII Galaxies, that can be traced to z~3 and used as distance indicators. In a recent research project, we have re-analysed the observed correlation for Giant HII regions in order to establish the zero-point of the regression, essential for the extension to cosmological distances. Accurate emission line photometry showed that evolutionary effects introduce a large scatter in the regression and we found that the brightest knots of three GHRs in M101 seem to follow the regression at the high luminosity end, in the range of the lower luminosity HII Galaxies. Their luminosities suggest they are up to 8 times brighter than NGC604, or 30 Doradus, although their linear sizes are quite comparable. The following steps point towards a detailed analysis of the stellar population and interstellar matter of these amazing starburts regions. We have obtained telescope time to perform broad band JHK photometry on NGC5471 However, our major uncertainty in the determination of the absolute fluxes (luminosities) came from the impossibility to use the Balmer decrement as estimation of the extinction.

GN-2002A-Q-24

Title: Imaging extra-solar planets

Abstract: We propose to obtain deep, near-IR (J) images of young, nearby white dwarfs, to detect massive planetary companions (>3Mj). Since the white dwarfs are evolved from 1.5-4Msol stars, we will in effect be probing the frequency of massive companions to solar type (and more massive) stars. Radial velocity surveys are heavily biased towards massive, short period planets and provide little or no information on systems with massive planets at large radii, such as our own. Our observations will probe exactly this region. By targeting white dwarfs we will obtain better contrast and angular separation (due to outward movement of the planets during primary mass loss) than surveys around main-sequence stars. These observations will, therefore, provide significant constraints on the frequency of massive planetary companions to solar-type (and more massive) stars, and potentially provide the first sample of extra-solar planets that can be directly observed.

GN-2002A-Q-25

Title: Distant cluster galaxy evolution: spectroscopic dissection of E+A galaxies.

Abstract: The enigmatic "E+A" galaxies, with their strong Balmer-line absorption signature superimposed upon a E-galaxy type spectrum, are conspicuous signposts of dramatic evolutionary events in distant clusters and in the field. Imaging and spatially resolved spectroscopy of the low-z LCRS field sample have suggested these objects to be the result of major mergers. However, little is known about the E+A galaxies in distant clusters, due to the paucity of data of this kind. We propose spatially resolved, intermediate resolution IFU spectroscopy with GMOS to determine the spatial and kinematical distribution of the young and old stellar populations in an archetypal sample of E+A galaxies in distant clusters. Combined with our high resolution HST imagery of these objects, these data will provide important clues as to the triggering mechanism for these objects in the rich cluster environment.

GN-2002A-Q-26

Title: A galaxy census at z ~ 1 in the GOODS/HDF-N region

Abstract: Most magnitude--limited redshift surveys become incomplete, especially as a function of galaxy type or color, at $z \approx 1$. Here we propose a comprehensive GMOS survey of galaxies at $z = 1.0 \pm 0.2$, pre--selected via photometric redshifts, in the HDF--N portion of the Great Observatories Origins Deep Survey (GOODS). GOODS unites the deepest observations from space-- and ground--based facilities to study the high redshift universe from X--ray through radio wavelengths. Extremely deep {\it SIRTF} Legacy observations at 3.6 to 24$\mu$m will measure rest--frame near--infrared light and redshifted 12$\mu$m PAH emission at $z = 1$. Together with GMOS emission line measurements, UV to near--IR photometry, radio observations, and existing and planned SCUBA surveys, these data will provide a thorough census of the stellar content and star formation rate distributions in galaxies when the universe was half its present size and $\sim$40\% its present age. 1~Msec {\it Chandra} imaging measures AGN activity down to low--level Seyfert luminosities, and several {\it HST}/ACS Treasury'' proposals have been submitted to observe galaxy morphologies over this region. All GOODS {\it SIRTF} and ground--based data, as well as {\it Chandra} and proposed {\it HST} observations are non--proprietary, enabling a wide range of community research activities.

GN-2002A-Q-27

Title: A Multi-Wavelength Study of the Circumnuclear Starburst Regions of M83

Abstract: We propose a multi-wavelength study of the circumnuclear starburst regions of M83, including 10 um, JHKL' images and multi-slit J,K-band spectroscopy. We will use the Brgamma equivalent width (EW) and the EW of the 2-0 CO absorption band at 2.3 um as age diagnostics for constraining both the age and the time scale of the burst at various spatial positions. Diffraction-limited images at 10 um will reveal the youngest stellar populations, possibly unveiling very young proto-globular clusters.

GN-2002A-Q-28

Title: Ionization cones and filaments in Active Galaxy Nuclei

Abstract: We propose to observe a sample of 3CR radio galaxies and quasars that are known to have conical (or bi-conical) structures of ionized gas related to the AGN of the host galaxy. Some of these structures are large with sizes comparable to the size of the host galaxy and are very luminous in the emission lines. There are several mechanisms that can in principle explain the features of these cones; the two most likely scenarios involve photoionization by UV photons or local shocks. These scenarios are supported by sophisticated theoretical models, which make predictions that can be tested with specific observations. The primary goal of our program is to obtain spectroscopy of the brightest emission lines in a sample of these objects. We will measure the ratio of the key emission lines and compare them with predictions and models from state of art diagnostic diagrams.

GN-2002A-Q-29

Title: Multi-Object Spectroscopy of the GC Systems of Luminous Ellipticals

Abstract: We will use GMOS to obtain multi-object spectroscopy of globular clusters in three luminous elliptical galaxies with bimodal globular cluster colour distributions. We will measure metallicity-sensitive and age-sensitive line-strength indices, investigating the mechanism, epoch and timescale of cluster formation. The cluster kinematics will reveal the dynamics of their sub-populations, further testing competing models of GC and galaxy formation. We will obtain galaxy mass profiles out to ~22 kpc, providing one of the few direct probes of dark matter in ellipticals at large radii.

GN-2002A-Q-30

Title: Cosmology with High-Redshift Type Ia Supernovae

Abstract: We now have the opportunity to obtain a Hubble diagram of Type Ia supernovae (SNeIa) that will be of longlasting value as a record of the expansion history of the universe. This record, based on SNeIa used as calibrated standard candles, directly constrains the cosmological parameters. As demonstrated by our successful observations of a redshift=1.06 supernova in 2001B, NIRI on Gemini is capable of providing crucial near-IR data (rest-frame V band) for the highest redshift supernovae. Combined with coordinated optical observations at other observatories, in particular HST, these provide powerful constraints on SNIa evolution and abnormal dust within or between galaxies. Meanwhile GMOS is capable of providing spectroscopic confirmation of the supernova's type and redshift, and optical lightcurves for faint supernovae. Accurate measurement of these high redshift SNe will dramatically shrink the major-axis of the error ellipse in the Omega_M--Lambda plane, decoupling the measurements of Omega_M and Omega_Lambda. This will provide the first check on the CMB measurements of a spatially flat universe, and unambiguously determine whether the universe contains vacuum energy. The Hubble diagram in this redshift range is the only currently feasible way to begin constraining the physics of the dark energy'' that is accelerating the universe's expansion.

GN-2002A-Q-31

Title: Cosmology with High-Redshift Type Ia Supernovae

Abstract: We now have the opportunity to obtain a Hubble diagram of Type Ia supernovae (SNeIa) that will be of longlasting value as a record of the expansion history of the universe. This record, based on SNeIa used as calibrated standard candles, directly constrains the cosmological parameters. As demonstrated by our successful observations of a redshift=1.06 supernova in 2001B, NIRI on Gemini is capable of providing crucial near-IR data (rest-frame V band) for the highest redshift supernovae. Combined with coordinated optical observations at other observatories, in particular HST, these provide powerful constraints on SNIa evolution and abnormal dust within or between galaxies. Meanwhile GMOS is capable of providing spectroscopic confirmation of the supernova's type and redshift, and optical lightcurves for faint supernovae. Accurate measurement of these high redshift SNe will dramatically shrink the major-axis of the error ellipse in the Omega_M--Lambda plane, decoupling the measurements of Omega_M and Omega_Lambda. This will provide the first check on the CMB measurements of a spatially flat universe, and unambiguously determine whether the universe contains vacuum energy. The Hubble diagram in this redshift range is the only currently feasible way to begin constraining the physics of the dark energy'' that is accelerating the universe's expansion.

GN-2002A-Q-32

Title: Line imaging of highest redshift QSOs

Abstract: We propose deep NIR imaging of QSOs in the redshift range 4.6 to 5.2 whose redshifted [O II] line emission lies in the passband of NIRI narrow band filters. A combination of K' and narrow-band images will map the stellar continuum and line emission from the QSO host galaxies and also provide candidates for associated galaxies in the QSO environment. This project makes use of the light gathering power, image quality and wide field of Gemini and NIRI. It will provide new evidence on the galaxy populations at very high redshift, and the triggering of the earliest QSOs.

GN-2002A-Q-33

Title: A Search for Disks around Young Brown Dwarfs and Very-Low-Mass Stars

Abstract: Recent surveys have identified candidate sub-stellar objects down to planetary masses in nearby star-forming regions, and provided preliminary indications of disk emission in some cases. Reliable determination of the disk frequency in young brown dwarfs is of paramount importance to understanding their origin. Here we propose to complete the first systematic study of L-band disk excess in a sample of spectroscopically confirmed objects near and below the sub-stellar boundary, using NIRI on Gemini North. The current proposal covers the Spring targets of a previously approved Gemini program.

GN-2002A-Q-34

Title: Galaxy Evolution During Half the Age of the Universe

Abstract: Detailed studies of nearby galaxies (z<0.05) have shown that galaxies have very complex histories of formation and evolution involving mergers, bursts of star formation, and morphological changes. Even so, the global properties of the galaxies (radii, luminosities, rotation velocities, velocity dispersions, and absorption line strengths) follow a number of very tight (empirical) scaling relations, e.g. the Tully-Fisher relation and the Fundamental Plane. These relations place constraints on models for galaxy evolution. The results for nearby galaxies rely on high signal-to-noise spectroscopy and multi-color photometry. With the Gemini Telescopes it is now possible to carry out similar detailed studies of galaxies at much larger redshifts, up to z~0.9, equivalent to half the age of the Universe. We have started a large project, using both Gemini Telescopes, aimed at studying the galaxy evolution over the last half of the age of the Universe. The project is based on a large database of spectroscopy and photometry of galaxies in 15 rich clusters of galaxies with redshifts between 0.15 and 0.9. We have been granted time on Gemini-North in 2001B (ranking band 1) to observe two clusters at redshifts 0.4-0.45. The present proposal covers GMOS spectroscopic and photometric observations of galaxies in the two rich clusters Abell 1689 at a redshift of 0.18 and RXJ1334.3+5030 at a redshift of 0.62.

GN-2002A-Q-35

Title: The evolution of high-redshift quasar host galaxies

Abstract: It is now apparent that most nearby massive spheroids harbour a black hole of proportionate mass. Consequently, black-hole and spheroid formation/growth are recognised as intimately-related processes, with the evolution of quasar host galaxies as a function of redshift now seen as a key measurement in observational cosmology. Using NICMOS on HST we have recently discovered signs that the properties of quasar hosts are beginning to change by z=2, and in Semester 2001B we will begin to use Gemini+NIRI to extend this study through the crucial cosmic epoch z=2-4. Here we propose to complete the quasar sample begun in 2001B. If the trends seen at z~2 continue to still higher redshift several current models of structure formation could be rejected. This project exploits the capabilities of Gemini+NIRI to the full, as we require both excellent image quality and the ability (impossible with NICMOS) to detect low-surface brightness emission at K.

GN-2002A-Q-36

Title: Constraining the Lifetimes of Circumstellar Disks:L band Observations of NGC 2362

Abstract: We propose to obtain deep JHKL$^\prime$ imaging of 200 stars in the young stellar cluster NGC 2362 using NIRI on Gemini North. We have shown that the combination of JHKL imaging photometry is capable of detecting essentially all of the circumstellar disks around young stars. Our proposed Gemini observations are critical for our overall program to determine the frequency and lifetimes of circumstellar disks in young stellar clusters, the preferred sites of star formation in our Galaxy. NGC 2362 is key to this program since it has an age of 5 Myrs. From our previous observations, this age is roughly equal to the timescale over which circumstellar disks are estimated to dissipate. The main goals of these proposed observations are to determine if the circumstellar disk fraction of all stars in NGC 2362, down to the hydrogen burning limit, is significantly reduced, as expected from its age and to test if the lifetimes of circumstellar disks are a function of stellar mass. This proposal was awarded 5 hours on Gemini North with NIRI during the 2001A and 2001B semesters with a ranking of 1. However, no observations were obtained due to the delay of the 1$^{st}$ NIRI queue for thermal near-IR imaging.

GN-2002A-Q-37

Title: Cosmology with High-Redshift Type Ia Supernovae

Abstract: The current Type Ia supernova Hubble diagram and CMB observations argue for a flat universe with some form of dark energy'' accelerating its expansion. Studies of distant supernovae can probe the expansion history of the universe through our current dark-energy-dominated era back to a matter-dominated era, making them one of the best current methods to study the amount and nature of such dark energy. With this program of SN studies we have an opportunity to obtain a Hubble diagram that will be of longlasting value as a record of the expansion history of the universe over the last 10 billion years. The CTIO 4-m telescope will reach back in time to find supernovae when the universe was still matter-dominated, extending our understanding of the expansion of the universe and possible evolution of supernovae over time. The Gemini GMOS will provide spectroscopic confirmation of a selection of these SNe and, together with the WIYN telescope, will allow us to obtain photometric follow-up -- and hence a measurement of the brightness of these standard candles as a function of redshift. The Gemini NIRI will allow us to obtain crucial data for the very highest-redshift ($z > 1$) supernova whose rest-frame V-band will have been redshifted to our J-band. The CTIO search triggers all of the confirmation and follow-up work requested here as well as that which we have requested at other facilities.

GN-2002A-Q-38

Title: The Eccentricity of Charon's Orbit

Abstract: We propose to use Hokupa'a to obtain high resolution images of the Pluto-Charon system with the goal being to measure and either confirm or refute the non-zero eccentricity indicated by HST observations made when the orbit was viewed more edge-on. This project was started in 2001, but bad weather caused some gaps in the orbital longitude coverage that need to be filled.

GN-2002A-Q-39

Title: Cosmology from High Redshift Supernovae

Abstract: Type Ia supernovae (SNIa) appear to be good standard candles, and the magnitudes of distant SNIa, coupled with their redshifts, can give us solid information about $q_0$. We have recently published a paper which claims that $\Omega_\Lambda > 0$ based on the fact that SNIa are fainter than would be expected at $z > 0.5$ without a cosmological constant. This result is {\it statistically} very reliable, but is vulnerable to systematic error. The most powerful and straightforward way to assess this is to push to significantly higher redshift, $z = 0.9{-}1.2$, because any reasonable systematic error will begin to deviate substantially from the effects of a $\Omega_\Lambda > 0$ cosmology at those redshifts.

GN-2002A-Q-40

Title: Imaging the BLR of the Gravitationally Lensed QSO 2237+0305

Abstract: Mediavilla etal (1998) have demonstrated that the CIII] emission region of the QSO 2237+0305 covers a caustic in the source plane, and is lensed into a long arc in the image plane. High resolution imaging of this arc in both the spatial and velocity domains using the GMOS IFU will allow us to deconvolve the image of the CIII] emission region. This will provide the first direct image of a QSO emission region. We will also image the MgII emission region, and determine the magnification of the quasar continuum regions which cannot be resolved with these observations. However determination of the magnification at the quasar positions will constrain models of the physical processes responsible for the continuum emission in quasars.

GN-2002A-Q-41

Title: Probing the assembly and evolution of $z \sim 1$ galaxies with spatially resolved IFU kinematics

Abstract: The internal kinematics of galaxies, measured through rotation curves and linewidths, trace their masses and M/L ratios. Velocity fields can also reveal whether a galaxy is relaxed and in ordered rotation, or has chaotic internal motions, as often seen in mergers. Kinematics of distant ($z \sim 1$) galaxies are thus a potentially powerful probe of their star formation and assemblage histories. Mass estimates and Tully-Fisher-like relations from velocity widths are reliable for these young galaxies if their clumpiness is due to hotspots of star formation within a young stable rotating disk. However, many $z\sim 1$ galaxies appear peculiar, asymmetric, or interacting, and instead we could be seeing the aggregation of infalling massive gas clouds or dwarf galaxies with more random motions. Which of these scenarios dominates among $z\sim 1$ galaxies remains unsolved but critical to our understanding of disk formation and evolution. We propose to address this question by using GMOS+IFU to observe [O II] emission from eleven $z \sim 1$ galaxies drawn from a larger HST-imaged sample previously observed with Keck single slitlets. With 2-D kinematic and emission-line imaging maps, we will determine if the young disks have organized rotation or more random motions of subclumps, provide the first solid high-z mass estimates, and determine the spatial distribution and symmetry of the line emission, tracing star formation.

GN-2002A-Q-42

Title: Rich Optically-Selected Galaxy Clusters at z~1 from the RCS Survey

Abstract: We propose to obtain GMOS spectroscopy on an initial sample of five 0.65<z<1.3 clusters drawn from the RCS, a large systematic high-z cluster survey. The spectroscopic confirmation of the photometric redshifts of these clusters will almost double the number of known z>1 clusters. We will obtain typically 35 to 50 cluster galaxy redshifts in each of these clusters allowing us to study the galaxy population and dynamical state of the clusters. The combination of this data set with lower redshift samples, X-ray, and SZ observations will allow us to perform comprehensive studies of the relationship between cluster and ICM properties, and the evolution of the cluster galaxy population and dynamical state, over an unprecedented redshift range.

GN-2002A-Q-43

Title: The evolution of typical AGN host galaxies

Abstract: We propose to use the ultra-high resolution offered by Gemini to image the host galaxies of typical, L* luminosity, AGN, and determine the evolution of host galaxy properties. Building on our Gemini observations at z=2 which show that host galaxies are at least as faint as expected in a passively evolving model, we aim to make clear detections of AGN host galaxies at z=1, to determine whether the luminosity of the hosts is consistent with passive evolution. In particular, we wish to determine whether AGN host galaxies become progressively fainter at higher redhsift. Our approach is unique in that we have selected our targets from the 2dF QSO Redshift Survey (2QZ), the only survey large enough to provide sufficient numbers of ~L* AGN which have nearby bright stars suitable for AO use. This approach offers the crucial advantage of avoiding the redshift-luminosity degeneracy that would otherwise compromise the search for evolutionary effects.

GN-2002A-Q-44

Title: The lifecycle of cluster galaxies: GMOS age-dating of K-band selected samples at z=0.4-0.6

Abstract: The galaxies in rich clusters experience extreme environments, tracing these back in time provides a direct route to investigate the role of environment in galaxy evolution. Two contrasting views have emerged: spectrophotometric/morphological studies indicate a radical change in the galaxy population across z=0-0.5, star-forming fraction is much larger in the past. In contrast studies of the Fundamental Plane and the colours of early-type galaxies see little change in their stellar populations to z=0.8, implying formation at high-z. These studies have used "traditional" cluster samples which have not changed significantly since the work of Butcher & Oemler, while their galaxy selection is equally poorly defined. Whether this has influenced their conclusions is a major uncertainty. We will address the apparent dichotomy amongst previous studies by determining the age/metallicity distribution of a 300 K-band selected galaxies down to ~0.3L* within the virialised regions of four z~0.4-0.6 X-ray luminous clusters.

GN-2002A-Q-45

Title: The Stellar Content of the Giant HII Region W51

Abstract: We propose to continue our survey of giant HII regions, aimed to trace the spiral structure of our Galaxy and to study the nature of massive star formation. Our distance determinations are based upon spectroscopic parallaxes of newly born OB stars. Our recent results have revealed clusters containing ZAMS OB stars and massive objects still accreting matter. Even the brightest cluster members of W51 require large aperture telescopes like Gemini for spectral classification in the K-band. This data set is also the starting point to determine the parameters of the stellar cluster, such as the initial mass function, stellar density and ionizing sources of the HII region.

GN-2002A-Q-46

Title: SN~Ia: The Collision of Theory and Observation

Abstract: Type~Ia supernovae can be reliable probes of cosmology if their explosion mechanism is better understood. Optical spectra of these events have provided important clues, but near-infrared wavelengths open a unique window with a number of key diagnostic features which provide direct estimates of progenitor metallicity and the density of transition from deflagration to detonation. There exist few high-quality NIR spectra of SN~Ia to compare with the detailed models. We propose a program to test the feasibility of obtaining NIR spectra of SN~Ia with NIRI and Gemini North. We will attempt $JHK$ spectra before maximum, at maximum and a few days after peak for three supernovae caught early in their development.

GN-2002A-Q-47

Title: SN~Ia: The Collision of Theory and Observation

Abstract: Type~Ia supernovae can be reliable probes of cosmology if their explosion mechanism is better understood. Optical spectra of these events have provided important clues, but near-infrared wavelengths open a unique window with a number of key diagnostic features which provide direct estimates of progenitor metallicity and the density of transition from deflagration to detonation. There exist few high-quality NIR spectra of SN~Ia to compare with the detailed models. We propose a program to test the feasibility of obtaining NIR spectra of SN~Ia with NIRI and Gemini North. We will attempt $JHK$ spectra before maximum, at maximum and a few days after peak for three supernovae caught early in their development.

GN-2002A-Q-48

Title: Black Holes in Brightest Cluster Galaxies

Abstract: The largest galaxies, and especially brightest cluster galaxies (BCGs), offer special insight into formation and evolution because they represent the extremes of these processes. Black holes are now believed to be essential components of galaxies, and their evolutionary states appear to be intimately linked to those of their hosts. By studying black holes in BCGs, we will push theoretical predictions for formation of both black holes and their hosts. We will measure central stellar kinematics in a sample of nearby brightest cluster galaxies using the IR CO bandhead. These IR observations are superior to any that are possible with the Hubble Space Telescope, because the surface brightnesses are too low for HST, and because of the good seeing of Gemini at K-band. The measured black hole masses will extend the black-hole/sigma correlation to its extreme end, testing black hole formation models. In addition, by combining these data with extensive kinematic coverage at McDonald Observatory, we will measure the stellar orbital distribution throughout the galaxies. This information directly probes the galaxies' evolutionary processes. Furthermore, these observations serve as a first step in opening up a potentially huge avenue in black hole research: once adaptive optics are available with IR spectrographs, many galaxies that cannot now be observed with HST will readily be feasible.

GN-2002A-Q-49

Title: A Search for Planetary-Mass Young Objects in the Serpens SVS2 Cluster

Abstract: This program is a continuation of our project to search for very low mass young brown dwarfs and planetary-mass objects in young, still embedded clusters. Very low-mass objects in the range of a few M_Jupiter are expected to have temperatures below 1300 K at the age of a few million years typical for young embedded clusters. At this low temperature, objects show methane absorption in their near-infrared spectrum that can be detected by two-filter differential photometry. A third filter, the J band in our project, gives a measure of the extinction and can be used to distinguish embedded low mass objects from potential foreground brown dwarfs. This method provides an unambiguous way of discovering embedded methane-atmosphere objects. Young objects of a few M_Jupiter are very faint (H = 21 - 24 in Serpens), however, and a substantial amount of integration time on a large telescope, combined with a large field of view are required to carry out this project. NIRI on Gemini is the best instrument for this project.

GN-2002A-Q-50

Title: The enigma of Terzan 1 globular cluster

Abstract: Terzan 1 is a Bulge globular cluster that presents an unprecedented color-magnitude diagram morphology, combining characteristics of metal-rich and metal-poor clusters. In this work we propose to observe a large sample of stars in central region of Terzan 1 using multi-object spectroscopy, to study its stellar population.

GN-2002A-Q-51

Title: The star formation history of the galactic bulge

Abstract: We propose to obtain sharp J and H-band images of the Baade's window in the Milky Way bulge in order to constrain 1) the old stellar population of the Galaxy, 2) the faint end of the mass and luminosity functions, and 3) the evolution of the star formation rate in the bulge. We aim for photometry of point sources down to H=23.5 with sigma_H ~ 5%, which combined with existing deep HST optical images, will make the deepest views of the Galactic bulge: - the deepest color-magnitude diagrams, - the deepest luminosity functions, and - the sharpest images. Combining the IR photometry with the HST data we will determine not only the age (and possible age range) of this component of the Galaxy, but also its mass function down to 0.05 M_sun, essential to understand the possible MACHO population towards the bulge. This proposal was approved before but we got no data due to Gemini problems.

GN-2002A-Q-52

Title: The Chemistry of the Extreme Outer Disks of Nearby Spiral Galaxies

Abstract: The history of the chemical enrichment of the outer disks of galaxies is poorly known, despite its importance for understanding galaxy disk formation and the chemical evolution of the Universe through lines of sight to distant objects. Is the metal content of the peripheries of disks the result of a slow continuous star formation process, or have external parts been contaminated primordially by the metals expelled from the massive starbursts during halo/bulge formation? Internal disk dynamics may have historically been even more important, especially if strong radial flows were induced by bars. We propose to use GMOS to measure O/H abundances of the faint HII region populations in the outer disks (R>R_25) of two spiral galaxies, one normal and the other barred to establish the chemical state of the extreme outer regions of galaxy disks in the light of the predictions for the above processes. The primordial pollution scenario predicts a flattening (or even increasing) gradient in the very outer part, while the bar scenario would produce a rather flat distribution in the inner disk, but thereafter a very steep negative gradient in the outermost parts of the disk.

GN-2002A-Q-53

Title: Multi-object Spectroscopy of Tidal Dwarfs in the Stephan's Quintet

Abstract: We propose a spectroscopic study of several tidal dwarf galaxies (TDGs) and giant HII regions in the tails of the giant galaxies and/or in the intra-group medium of the Stephan's quintet (Mendes de Oliveira et al. 2001). A compact group presents a unique environment in which to study the TDGs' formation mechanism. We propose to measure the metallicities and star-formation rates of the emission-line regions through multi-slit spectroscopy done with GMOS. Imagery and spectroscopy will give us constraints on the formation scenarii of TDGs. If we find that the TDGs have the same metallicity as the parent galaxies, this will be a strong indication that it has had a recent formation and a tidal origin.

GN-2002A-Q-54

Title: Search for Asteroidal Satellites using Adaptive Optics

Abstract: We propose to make adaptive optics observations of faint (Vmag 14.5--17.0) asteroids to search for companions. The new Gemini AO system is the only instrument that will allow us to probe this brightness regime. Doing so will allow us to increase the number of objects available to our overall survey, necessary because we have already shown that satellites are not common. In addition, it will give us access to new classes of asteroids that have previously been largely beyond our reach. For example, both the Trojans (objects at Jupiter's Lagrangian points) and near-Earth asteroids have been suspected of having a high probability of harboring companions. Our overall program also uses the complementary facilities at CFHT and Keck. To date, we have discovered 5 asteroid companions (only 7 have been imaged from Earth). In our first run at Gemini, just completed, we observed over 100 targets (our goal was 20), recovering 2 known systems and substantially improving knowledge of their orbits, and we discovered a new, highly unexpected system. Asteroid satellites give us vital insight into the nature of asteroids in two ways: (1) the presence of a moon allows the mass of the primary to be determined, hence its density, thus giving key information of the asteroid's structure and composition, and (2) the moons were almost certainly formed by collisions and collisions are a fundamental process that shaped most solar system objects.

GN-2002A-Q-55

Title: Are the hosts of Gamma-Ray Bursts luminous starbursts or normal galaxies?

Abstract: Present knowledge indicates that most gamma-ray bursts (GRBs) are linked to the collapse of massive stars. Because gamma-rays are not attenuated by intervening dust and gas, the selection of the cosmic sites of massive star formation by this method is less affected by the biases associated with optical-uv surveys (e.g. UV-dropout technique). As a complement to the imaging and spectroscopic observations of southern GRB host galaxies that we have carried out in periods P67 and P68 with FORS and ISAAC on the VLT, we propose to perform low-resolution spectroscopy of northern GRB host galaxies on Gemini North. The immediate purpose of this program is to characterize the physical properties of GRB hosts, and to determine whether GRBs occur in normal galaxies. The crucial issue would lead, in the future, to use GRB occurance rate as a direct measurement of the cosmic star formation history even in dusty enshrouded regions.

GN-2002A-Q-56

Title: 3-4 $\mu$m Spectra of L and T Dwarfs

Abstract: The late L dwarfs and early T dwarfs remain the most poorly characterized objects in the substellar sequence. The most profound physical change at this class boundary is the change in carbon chemistry from CO- to CH$_4$-dominated as temperature decreases. Direct observations of this changeover are very limited. We have identified the 3.3 $\mu$m $\nu_3$ band of CH$_4$ in an L5 and and L7.5 dwarf (Noll et al.~2000), the warmest objects in which CH$_4$ has been detected. Also several T dwarfs with weak near-IR bands are now known (Leggett et al.~2000) and have begun to fill in the gap between objects with strong near-IR methane like Gl~229B (Oppenheimer et al.~1998), and the L dwarfs which show no near-IR methane. The 3-4 $\mu$m interval offers a unique opportunity to study this transition with a strong band free of spectral contamination and in objects with few other distinguishing spectral features. Observations will allow us to constrain effective temperatures, clouds, and carbon chemistry as well as establishing the smoothness and completeness of the existing brown dwarf inventory at the L/T boundary.

GN-2002A-Q-57

Title: Spectroscopic Confirmation of z=4.4 Galaxies

Abstract: We have found ~800 candidate star forming galaxies at z=4.4 using the CFH12K camera through a search for Lyman-alpha emission (1216 Angstroms) redshifted into the bandpass of the CFH12K H-alpha (6563 Angstrom) filter. During 2001B, we will obtain BVRI observations to remove local contaminants from our sample. To confirm the efficiency of removal, we require spectra of a representative sample from our catalog. Including overhead, 8 hours of queue time with GMOS is required (11 hours during gray time).

GN-2002A-Q-58

Title: A Census of $z > 4$ Galaxies

Abstract: Although recent discoveries have yielded galaxies with redshifts up to $z\appx 5.7$, statistical samples of galaxies at these redshifts are still extremely limited. Recent evidence for reionization near $z \appx 6$ makes this redshift range the most interesting for studying galaxy formation and evolution. We propose to triple the number of spectroscopically confirmed $z \ga 4.3$ galaxies with Gemini. The candidates for spectroscopic followup are selected using two criteria: (1) Strong \lya\ line emission from the Large Area Lyman Alpha (LALA) survey at z=4.5 \& 5.7 and (2) broadband colors (Lyman-break galaxies) from the NOAO Deep Wide-Field Survey (NDWFS). These two selection methods are complementary and using both samples will yield the most complete optically selected sample of $4 \la z \la 7$ galaxies. Ly-$\alpha$ selected galaxies typically have low luminosities and high \lya\ equivalent widths, indicating young stellar populations ($\le 10^7$ years old) with little or no dust. Lyman-break galaxies are typically more luminous, with weak \lya\ emission or absorption, and may be more evolved. We will use the spectroscopic sample to refine photometric classification methods, in order to leverage much larger samples from LALA and NDWF surveys and extend redshift determinations to lower luminosities. The sample will be used to study galaxy evolution between $z=4.5-6.8$. We will have large enough samples to robustly determine luminosity functions, star formation rates, and clustering properties of the sample as a whole and of the Lyman-break and \lya\ populations seperately. We will also study the relationship between the continuum- and line-selected galaxies. In particular, we will determine whether the the lower bolometric luminosities of the line-selected samples imply correspondingly lower halo masses by comparing clustering of the two samples.

GN-2002A-Q-59

Title: What are the Damped Lyman Alpha 'protogalaxies'?

Abstract: Damped Lyman Alpha (DLA) absorptions in quasar spectra have been known for years. It is now realised that at redshifts z~2 the objects causing these absorptions represent the majority of baryons available for later star formation, i.e. they are protogalaxies in some form. But the nature of high-redshift DLAs is unclear, with rotating discs or chaotically moving pre-galactic clumps being the main contenders. Part of the problem is that absorption probes only a single line of sight through the object. There are, however, a few cases in which Lyman alpha emission has been detected from DLAs. We propose to observe one of these, Q0836+113, with GMOS and its IFU. Two dimensional spectral coverage will be ideal, enabling us to find the size and morphology of the object, and its mass from spectral dynamics. The distribution of star-formation rate can be determined from the line flux. The DLA trough blanks out the quasar over the relevant wavelength interval, leaving the emission feature to be seen against a black background. Adequate signal/noise can be obtained in 4 hours total exposure.

GN-2002A-Q-60

Title: At the Epoch of Reionization

Abstract: We propose a deep spectroscopic search for LyA-emitting galaxies at two epochs (z~5.7 and z~6.5) that bracket the recently identified Epoch of Reionization at z~6. In the absence of evolution, we expect to find ~22 LyA emitters at each redshift. However, if star-forming galaxies are responsible for reionizing the Universe, there should be dramatic evolution in their number density from z~6.5 to z~5.7. Finding such strong evolution will confirm that the Epoch of Reionization lies at z~6, and will identify LyA emitters as the population responsible for reionizing the Universe.

GN-2002A-Q-61

Title: Near Infra-Red Imaging of Tidal Dwarf Galaxy Candidates in Stephan's Quintet

Abstract: We propose to image in J, H and Kprime the star-formation regions of Stephan's quintet, a small group of galaxies at at distance of 80 Mpc. Most of its gaseous material is not concentrated around the bright galaxies of the group but in the intragroup medium instead, suggesting that collisions among the group members may have taken place. A number of HII regions and tidal dwarf candidates have been identified by us around two of the brightest galaxies of the group (see Fig. 1). Our main goal is to resolve the several components of each region, to obtain their stellar masses and to date the bursts of star formation through analysis of B,R,J,H,K imaging.

GN-2002A-Q-62

Title: Characterization of the sources contributing to the cosmic infrared background

Abstract: We propose to continue the identification of and characterization of the ISO deep field sources in the Lockman Hole North East area. This is a critical first step toward understanding the nature of the sources contributing to the infrared background. These sources have an enormous impact on the derivation of the star formation history of the universe. We aim at identifying the faintest sources using Suprime-Cam imaging of the central part of our field, and extend in colors our CFH12K data of semester 200B, in order to produce photometric redshifts for the whole area. The photometric redshift will be calibrated by obtaining multi-object spectroscopy on a portion of the field where our infrared data are the deepest.

GN-2002A-Q-63

Title: The Galaxy Group Environment at z=1

Abstract: The decline in global star formation with time may be due to internal galaxy processes (i.e. gas consumption) or the effect of large-scale structure and the hierarchical growth of the universe. Observations of galaxies in different environments, out to the highest possible redshifts, can distinguish between these models. We will use GMOS spectroscopy to constrain star formation rates and stellar masses in low-mass clusters and groups at $z=1.1$, which are the least-well explored environments at this important epoch. We target the huge supercluster B21335+28, in which we have identified numerous groups and subclumps from deep optical and near-infrared imaging. Combined with our data on groups and low-mass clusters at lower redshifts, we can put interesting constraints on the environment-dependent evolution of star formation in the universe.

GN-2002A-Q-64

Title: Multi-Object Spectroscopy of the GC Systems of Luminous Ellipticals

Abstract: We propose to use GMOS to obtain multi-object spectroscopy of globular clusters in three luminous elliptical galaxies which have bimodal globular cluster colour distributions. We will measure metallicity-sensitive and age-sensitive line-strength indices for the clusters, investigating the mechanism, epoch and timescale of their formation, thereby probing the galaxies' stellar assembly. Kinematics for the clusters will reveal the dynamics of their sub-populations, further testing competing models of cluster formation. We will obtain mass-profiles for the galaxies out to $\sim$ 22 kpc, providing one of the few direct probes of dark matter in ellipticals at large radii. Gemini-N/GMOS is unique in providing {\it large numbers} of high-quality cluster spectra, to simultaneously derive ages, metallicities $and$ kinematics for the globular clusters.

GN-2002A-Q-65

Abstract: We propose to perform a pilot study with GMOS long slit spectroscopy, to test both a hypothesis and a procedure, following two recent discoveries. The hypothesis is that powerful radio galaxies are triggered by galaxy-galaxy mergers (studies to date are exclusively morphological, never yet kinematical which is the aim of this proposal). The first discovery is that we have recently found, following deep K-band imaging on UFTI that a number of our high-z radio galaxies have a pair of host galaxies, rather than just one. This appears consistent with the above hypothesis, which is lent further support following our second discovery, published in Nature, of the Youth-Redshift degeneracy for high-z radio galaxies: this leads to high-z radio galaxies being inevitably significantly younger the dynamical timescales for galaxy-galaxy mergers. The procedure we wish to test is whether even GMOS is sufficient to reveal the nature of both high-z host' galaxies, if e.g. only one of the pair of galaxies is active'.

GN-2002A-Q-66

Title: The Enigma of "E+A" galaxies

Abstract: The cluster environment is hostile to star formation in galaxies. It is puzzling therefore that many galaxies in intermediate redshift clusters have strongly enhanced balmer lines indicative of a recent burst of star formation. These are the "E+A" galaxies. The star burst in these galaxies may be the result of galaxy galaxy interactions, or may result from the rapid truncation of star formation as a disk galaxy suddenly experiences the ram pressure of its motion through the cluster. The aim of this propsal is to distinguish between these scenarios by examining the spatial distribution of the star burst. The GMOS IFU provides us with an unparalleled oportunity to understand these enigmatic objects.

GN-2002A-Q-67

Title: DORIS: A Deep Redshift Survey with Gemini North

Abstract: We propose an international collaboration to carry out a deep redshift survey using Gemini North and GMOS. The aim is to measure redshifts for 20000 galaxies in four rectangular regions selected from the SDSS Early Data Release to I=22. The main scientific goals of the survey are: (i) To execute a detailed analysis of how galaxy clustering depends upon properties such as luminosity, colour, morphological and spectral type and to determine precisely how the clustering signal evolves with redshift. (ii) To construct a group catalog at intermediate redshifts; this can be utilized in numerous ways, for example, to study how galaxy star formation rates depend upon environment. (iii) To determine how the field luminosity function evolves with redshift. The proposed project will fill an embarassing gap in our knowledge of the Universe, building upon the local surveys now underway (2dFGRS, SDSS). Previous surveys to intermediate redshifts have only been able to scratch at the surface of the issues that we wish to address. Furthermore, the goals of our survey cannot be achieved with the SDSS red galaxy survey, because of its specialised selection. The data obtained will be important for a host of follow-up scientific projects and will provide an invaluable resource for other researchers in the community to exploit.

GN-2002A-Q-68

Title: DORIS: A Deep Redshift Survey with Gemini North

Abstract: We propose an international collaboration to carry out a deep redshift survey using Gemini North and GMOS. The aim is to measure redshifts for 20000 galaxies in four rectangular regions selected from the SDSS Early Data Release to I=22. The main scientific goals of the survey are: (i) To execute a detailed analysis of how galaxy clustering depends upon properties such as luminosity, colour, morphological and spectral type and to determine precisely how the clustering signal evolves with redshift. (ii) To construct a catalog of groups at intermediate redshifts to study, for example, how galaxy star formation rates depend upon environment. (iii) To determine how the field luminosity function evolves with redshift. The proposed project will fill a major gap in our knowledge of the Universe, building upon the local surveys now underway (2dFGRS, SDSS). The goals of our survey cannot be achieved with the SDSS red galaxy survey, because of its specialised selection. The data obtained will be important for a host of follow-up scientific projects and will provide an invaluable resource for other researchers in the community to exploit.

GN-2002A-Q-69

Title: Comparing the Stellar and Gas Phase Metallicities in Nearby Dwarf Irregular Galaxies

Abstract: We propose to use the strength of 2.3 micron CO absorption in bright red giant branch stars to estimate the mean global metallicities (i.e. [M/H], as opposed to single-element values such as [Fe/H], [O/H], etc.) of stars in the nearby isolated dwarf irregular galaxies Leo A, SagDIG, and Pegasus. These galaxies have gas phase metallicities determined from HII regions. With the proposed observations it will be possible to compare the stellar and gas phase metallicities, and thereby probe the chemical evolution of these systems. In particular, if the gas phase metallicity, which is derived from observations of species such as oxygen that are formed mainly in SN II, differs significantly from the global metallicity, which will be derived here, then the chemical enrichment history must have been episodic, involving rapid bursts of star formation. However, if the gas and stellar metallicities are similar then a slow enrichment history is implied. The results from this study will also provide a means of calibrating the global metallicities of more distant systems, where individual stars can not be resolved, and the chemical composition is infered by necessity from emission line spectra. Finally, these data will also be used to investigate the AGB content of these systems, and thereby probe their star-forming histories during intermediate epochs.

GN-2002A-Q-70

Title: Harvesting the High Redshift Cluster Candidates from the ROX Survey

Abstract: The ROSAT Optical X-ray survey (ROXS) team has not only found distant clusters of galaxies but seeks to critically test the optical and X-ray methods used to identify cluster candidates. We simultaneously applied automated X-ray and optical (I-band, 4-meter) cluster detection techniques to the same areas of sky and identified 152 optical cluster candidates and 52 X-ray candidates. To provide a rigorous test of the optical and X-ray cluster detection methods, we must confirm which non-detections of each method are actually clusters. To this end, we propose to obtain J and K-band imaging of the 6 best X-ray candidates without I-band counterparts. The color will aid in redshift estimation. Distant clusters ($z>1$) are more pronounced in the near-IR than at I-band The presence of extended X-ray emission is an extremely robust indicator of a massive gravitational potential and an unambiguous signature of a galaxy cluster. With our X-ray observations, we already know that massive clusters are detectable to $z\sim1.4$.

GN-2002A-Q-71

Title: A multi-wavelength study of the two most massive galaxy clusters known at z~1

Abstract: ClJ1226.9+3332 and ClJ1415.1+3612, recently discovered by us, are the most distant X-ray luminous clusters currently known. At z=0.89 and z=1.01 these systems are more luminous (~ massive) than any other known cluster at similar or higher redshift. IF they are virialized (a crucial requirement), their mere existence imposes tight constraints on cosmological parameters of structure formation. Our multi-wavelength study of these exceptional systems uses observations of the Sunyaev-Zel'dovich effect with the BIMA radio interferometer to measure the pressure of the intra-cluster gas, and X-ray observations with Chandra and XMM-Newton to measure the cluster gas density and temperature distribution. Weak-lensing observations with HST are planned (ClJ1226.9+3332: 28 orbits awarded, scheduled to execute in May 2002; ClJ1415.1+3612: 24 orbits proposed for Cycle 11) and will allow us to constrain the projected distribution of dark matter. The deep Gemini/GMOS observations of the galaxy population in both systems proposed here will test whether these clusters are virialized by searching for substructure along the line-of-sight that would not be detectable by any other observational technique.

GN-2002A-Q-72

Title: Understanding Supermassive Black Holes and Their Host Galaxies

Abstract: Our hopes of understanding the nature of the connection between supermassive black holes (BHs) and their host galaxies have recently been boosted by the discovery that BH mass, and the stellar velocity dispersion of the surrounding bulge, follow a remarkably tight relation, $M_{BH} \propto \sigma^{\sim 4.5}$. Important parameters such as the local mass density in black holes, and the impact of galaxy merging on BH evolution, hinge critically on the exact characterization of this relation. In April 2001, we started a project with the Kitt Peak 4m Mayall telescope to map onto the $\ms$ plane a sample of nearby AGNs and QSOs, for which the mass of the central BH is known from reverberation mapping studies. Our preliminary results (Ferrarese et al. 2001) are encouraging, but the small sample of six AGNs prompted us to use caution in interpreting the results. We have been granted four 4m nights in October 2001 to extend our study by observing nine additional AGNs. These data will exhaust the limit at which this project can be carried out using the Mayall telescope. Here we ask for four nights of Gemini time to target the remaining ten fainter and more distant QSOs in our sample. The complete same of 25 AGNs will allow us 1) to firmly establish whether bright AGNs follow the same $\ms$ relation defined by quiescent galaxies ; and 2) to characterize the slope, normalization and scatter of the $\ms$ relation.

GN-2002A-Q-73

Title: SN~Ia: The Collision of Theory and Observation

Abstract: Type~Ia supernovae can be reliable probes of cosmology if their explosion mechanism is better understood. Optical spectra of these events have provided important clues, but near-infrared wavelengths open a unique window with a number of key diagnostic features which provide direct estimates of progenitor metallicity and the density of transition from deflagration to detonation. There exist few high-quality NIR spectra of SN~Ia to compare with the detailed models. We propose a program to test the feasibility of obtaining NIR spectra of SN~Ia with NIRI and Gemini North. We will attempt $JHK$ spectra before maximum, at maximum and a few days after peak for three supernovae caught early in their development.

GN-2002A-Q-74

Title: The VLA 1623 Molecular Hydrogen Outflow: Tracing the Impact Zone of a High Velocity Stellar Flow

Abstract: We propose to obtain NIRI K grism spectra of the molecular hydrogen outflow associated with the VLA 1623 proto-star, one of the youngest (10^5 yrs) and active object in the Rho Oph embedded cluster. We have selected four slit positions that will allow us to observer both the diffuse (jet-like emissions) and compact (knotty or HH-like structures) present in this outflow. H_2 as well as several H I lines between 1.9 -- 2.5 micron will provide physical and kinematical information on the impact zone where hot atomic and molecular gas in the stellar jet meets the much cooler molecular gas in the surrounding cloud and forms the large scale 12^CO outflow. In particular, these spectra will allow us to derive electron densities and temperatures along the outflow. Relative line strengths will provide constraints to the different mechanisms of line formations. We also expect to be able to constrain the velocity field of the HH knots (approaching and receding material) using radial velocities derived from the NIRI moderate resolution (R = 1300) spectral line measurements. Typical HH-knots/jets velocities range from 50 to 500 km/sec. These data will place better constraints on physical mechanisms for jet formation and for the interaction of jet material with the ambient cloud, in particular on the impact or transition zone where the stellar jet interacts with the surrounding cloud.

GN-2002A-Q-75

Title: Probing the high redshift Universe via quasars with z>5

Abstract: GMOS will be used to obtain identification spectra of z>5 quasars. The ultimate goals of the project are: (1) Establishing the contribution of AGN to the integrated UV background at the highest possible redshifts. (2) Establishing unambiguously the rate of decline in the QSO space density to z~6.5 via the explicit detection of the characteristic knee' in the quasar luminosity function ; (3) Determining the epoch of reionization via the Gunn-Peterson test; (4) Identifying a sample of z>5 damped Lyman alpha absorbers. The QSO candidates have been selected from our recent deep imaging survey at CFHT, which goes more than two magnitudes fainter than the Sloan survey and includes quasars well below the knee of the luminosity function. The success of our selection method is demonstrated by our rediscovery of an SDSS QSO at z=4.99. This, combined with the recent success of GMOS commissioning, gives us confidence to expand the survey. By adding the proposed observations to those scheduled in 2001B we will complete one survey field, an area of 1.8sq deg, in which we expect to find about 8-9 z>5 QSOs.

GN-2002A-Q-76

Title: The galaxy environment of z=2 QSOs

Abstract: We propose to obtain spectra of galaxies in the vicinity of two z~2 QSOs: one radio-loud and one radio-quiet. The QSO fields have been imaged with the HST and have known magnitudes and positions. The companions are different in the two environments in a way that appears to be typical of the RL/RQ dichotomy: the RLQ has large and irregular companions and the RQQ has fainter and more compact companions. The galaxies are considered to be likely companions by their strong concentration about the QSO. Spectroscopy is the most effective way to determine a) the true distribution of companions at the QSO redshift; b) the stellar populations in these galaxies; and c) the dynamics of the galaxy groups which will predict their subsequent evolution by merging or dispersal.

GN-2002A-Q-77

Title: Direct Detection of Giant Planets Around the Nearest Young Stars

Abstract: We propose to use Gemini Hokupa'a/QUIRC AO imaging to search for young planets and brown dwarfs around ~20 of the nearest young stars identified to date. Because of their youth, such planets are predicted to be quite luminous in the near-infrared and could be detected down to very low masses. As our 2000B Quickstart observations have shown, the Gemini AO system is capable of detecting companions with a contrast ratio of 10 magnitudes at H within 0.5 arcsec of the primary. At the 10-50pc distances of the carefully selected targets, that is sufficient to detect a Jupiter-mass companion at 5-25AU from its parent star. Thus, our program offers the prospects of finding a young Jupiter analog. Follow-up proper motion observations and distinctive colors of any candidates we find can be used to confirm their youth and association with the primary.

GN-2002A-Q-78

Title: Using IR Surface Brightness Fluctuations to Measure the Star Formation History of Galaxies in the Coma Cluster

Abstract: Infrared surface brightness fluctuations (SBFs) have proven to be both an accurate distance indicator and a powerful tool for probing the properties of unresolved stellar populations of early-type galaxies. We have calibrated the technique and used it to measure the spread in ages of ~65 early-type galaxies in the local universe. SBFs scale as the second moment of the luminosity function (or L^2), and are very sensitive to the brightest (and youngest) stars in a population. In the near-IR, SBFs break the well-known degeneracy between age and metallicity. Our survey of absolute fluctuation magnitudes in a range of galaxy types reveals a wide spread in age and a limited range in metallicity. This is in contrast to the conclusions of some authors who find (using age-sensitive absorption lines like H-beta) that the color spread in elliptical galaxies in clusters is due to variations in metallicity, not age. About half the galaxies in our sample are members of clusters (Fornax, Virgo, and Leo). The spread in age appears to be similar for elliptical and S0 galaxies alike. We propose to use NIRI to collect H-band SBF data for a sample of ~29 galaxies near the center of the Coma cluster to better understand the history of star formation in galaxies in rich environments. These galaxies represent a wide range of luminosity and H-beta index, and are all within 15 arcmin of the dense central core of the Coma cluster. Coma is by far the best-studied rich cluster in the nearby universe, and serves as a stepping stone in the interpretation of observations of more distant clusters. There is also some disagreement about whether the ellipticals in the Coma cluster are all uniformly old, or if their populations span a significant range in age. The proposed observations will tell us how long it has been since the youngest stars in a galaxy formed, and thereby provide an important independent check on galaxy age and metallicity estimates made using common absorption line indices.

GN-2002A-Q-79

Title: Confirming and Characterizing Young Lyman-$\alpha$ Galaxies at $z=4.5$

Abstract: Our knowledge of galaxies at $z \ga 3$ depends heavily on their rest-frame UV properties. This is especially true for \lya\ emitting galaxies, which will preferentially include the youngest and most chemically primitive objects. Redshifts of these sources are based on a single line, which is identified as \lya\ with circumstantial evidence (line asymmetry and a continuum break) (Stern \& Spinrad 1999). Their other properties are inferred from $1500$\AA\ continuum emission, which is insensitive to older stellar populations. We will remedy this situation with near-infrared (K band) spectroscopy and imaging of confirmed $z\approx 4.5$ galaxies from our Large Area Lyman Alpha (LALA) survey. Our NIRI observations will allow us to confirm and characterize these early galaxies in four important ways:\\ (1) The \lya\ redshift will be confirmed by detection of the \oii\ line.\\ (2) The \oii\ line will yield star formation rate (SFR) estimates. Comparing these to \lya\ and UV continuum SFR measurements will cross-calibrate SFR indicators normally used at different redshifts, and will test for dust absorption in our \lya\ sources.\\ (3) K band photometry can be compared to existing R, I, and z' data to look for light from old'' ($> 10^8$ years) stellar populations. Our NIRI spectra will also observe the $4000$\AA\ break, providing another test for old stars and lifting the degeneracy between dust and age in broadband colors. Old stars, if present, would have to have formed at $z \ga 6$.\\ (4) Rest optical light morphologies can be compared to the expectations from monolithic collapse and hierarchical formation scenarios, and can also directly compare newly-formed galaxies with their present day counterparts.

GN-2002A-Q-80

Title: Confirming and Characterizing Young Lyman-$\alpha$ Galaxies at $z=4.5$

Abstract: Our knowledge of galaxies at $z \ga 3$ depends heavily on their rest-frame UV properties. This is especially true for \lya\ emitting galaxies, which will preferentially include the youngest and most chemically primitive objects. Redshifts of these sources are based on a single line, which is identified as \lya\ with circumstantial evidence (line asymmetry and a continuum break) (Stern \& Spinrad 1999). Their other properties are inferred from $1500$\AA\ continuum emission, which is insensitive to older stellar populations. We will remedy this situation with near-infrared (K band) spectroscopy and imaging of confirmed $z\approx 4.5$ galaxies from our Large Area Lyman Alpha (LALA) survey. Our NIRI observations will allow us to confirm and characterize these early galaxies in four important ways:\\ (1) The \lya\ redshift will be confirmed by detection of the \oii\ line.\\ (2) The \oii\ line will yield star formation rate (SFR) estimates. Comparing these to \lya\ and UV continuum SFR measurements will cross-calibrate SFR indicators normally used at different redshifts, and will test for dust absorption in our \lya\ sources.\\ (3) K band photometry can be compared to existing R, I, and z' data to look for light from `old'' ($> 10^8$ years) stellar populations. Our NIRI spectra will also observe the $4000$\AA\ break, providing another test for old stars and lifting the degeneracy between dust and age in broadband colors. Old stars, if present, would have to have formed at $z \ga 6$.\\ (4) Rest optical light morphologies can be compared to the expectations from monolithic collapse and hierarchical formation scenarios, and can also directly compare newly-formed galaxies with their present day counterparts.

GN-2002A-Q-81

Title: Buried AGN in LINER-type Ultraluminous Infrared\\ Galaxies

Abstract: Ultraluminous infrared galaxies (ULIRGs) have been used extensively to trace the star formation history in the early universe. However, our current understanding of these galaxies is still scant. The major issue for understanding ULIRGs is to determine the relative energetic importance of AGN and star formation, which becomes very difficult if the AGN is buried in a thick dust shell. Previous studies have been hampered by high nuclear extinctions and/or serious ambiguities in the methods used to quantitatively distinguish between buried AGN and star formation. At 3--4 $\mu$m, dust extinction can be sufficiently low that buried AGN are detectable. Furthermore, we have diagnostic tools available to unambiguously quantify the energetic roles of buried AGN and star formation. We propose 3--4 $\mu$m spectroscopy of ULIRGs with the NIRI, focusing on ULIRGs classified optically as LINERs ($\sim$40\% of ULIRGs), because buried AGN are theoretically predicted to show LINER optical spectra. With 3--4m class telescopes, we have found strong evidence for energetically dominant buried AGN in two out of three exceptionally bright LINER ULIRGs. We plan to extend this successful approach to fainter LINER ULIRGs to investigate whether energetically important buried AGN are common in LINER ULIRGs.

GN-2002A-Q-82

Title: The ABCs of BCDs

Abstract: Blue compact dwarf galaxies (BCDs) may be pivotal to understanding the origin of dwarf spheroidal galaxies and the nature of faint blue galaxies. With the recognition that dIs in the field have evolved as isolated units, the correlation between metallicity and the gas fraction can be used to determine definitively whether BCDs have gained or lost gas. To separate young and old populations and arrive at valid gas fractions, we propose to image 10 BCDs in the Virgo Cluster in the near-IR.

GN-2002A-Q-83

Title: Brown Dwarfs in the NOAO Deep Wide-Field Survey and the Substellar Mass Function

Abstract: The NOAO Deep Wide-Field Survey will enable a detailed look at the substellar IMF in the field. The unique combination of red and infrared survey bands are ideal for selecting brown dwarfs and obtaining a rough measure of their effective temperatures. In addition, the faint flux limits of the survey will probe 10 times the depth probed by 2MASS. Here we propose to obtain far-red spectroscopy of a subsample of substellar candidates from the survey in order to quantify the rate of contamination from galaxies and other non-substellar interlopers in the substellar candidate sample. When corrected for the interloper contamination, the resulting IMF will sample older ages and lower masses than the 2MASS substellar IMF. We will also be able to address whether the 2MASS substellar IMF is a local phenomenon or representative of a larger region of the Galaxy.

GN-2002A-Q-84

Title: Sub-mm EROs, photometric redshifts, and the cluster gravitational lens A2218

Abstract: We propose to use NIRI to undertake a high-resolution J/K survey of the core of the massive cluster lens A2218, which has been imaged in BVRI with HST, and which we have surveyed to mJy depths using SCUBA at 850 and 450 microns. We will combine the Gemini observations with the HST data to produce accurate photometric redshifts for background galaxies seen through the cluster lens. We are especially interested in detailed study of the galaxies associated with the SCUBA sources; these can be detected at the limit of 4m IR imaging as heavily extinguished EROs (Extremely Red Objects). Photometric methods are the only realistic route to obtaining redshifts in these cases, requiring good S/N infrared data. High-resolution NIRI imaging, plus gravitational magnification, offers an exciting opportunity to probe the detailed structure of these poorly-understood objects. Finally, we will detect many gravitationally-lensed arcs, whose redshifts can be estimated geometrically. This comparison will be the first independent test of photometric estimates at flux levels 10 times fainter than has been possible using classical spectroscopy, and will validate this technique for future use in very wide-field surveys of large scale structure with WFCAM/VISTA/etc.

GN-2002A-Q-85

Title: Extremely Red Objects in the Direction of the Globular Cluster M4: A Globular Cluster Deep Field

Abstract: We have obtained extremely deep HST imaging (to V = 29.7) in M4, the nearest globular cluster. We also have on hand shallower data from an earlier epoch taken 6 years ago. This has allowed us to proper-motion clean the data and produce remarkably uncontaminated (by field stars and galaxies) colour-magnitude diagrams. In the process of doing this we have found a sample of about a dozen objects that are present on a 7,000 second I exposure but are absent from a 140,000 V exposure! This sets the V-I colour to be at least 6.0 for the brightest object. At least 4 of these objects have proper motions appropriate for cluster members. These stars are far redder than what appears to be the termination of the cluster main sequence, and redder than the reddest Population II field subdwarfs known. What can these objects be? In truth we do not know. Cluster brown dwarfs are unlikely as brown dwarfs this old would have faded well below detection by now. They may be a very low mass extension of the main sequence, possibly He white dwarfs, tidally heated brown dwarfs or other exotica. Some of the field objects appear to have proper motions typical of Galactic bulge stars and a few are not moving at all - so they may be Lyman break galaxies at redshifts as high as 6. We plan to obtain NIRI exposures in JHK in order get spectral energy distributions of these objects from V through K and to help solve the mysery of their identity.

GN-2002A-Q-86

Title: Characterizing Galaxies Around Damped Lyman-Alpha QSO Absorbers

Abstract: We propose GMOS deep imaging and multi-slit spectral observations of faint galaxies detected in the vicinity of the QSOs Q1331+170 (z_em = 2.084) and Q1756+237 (z_em = 1.721), both of which exhibit complicated absorption-line spectra with several intervening metal-line absorbers evident at various redshifts. Each of these spectra harbors at least one damped Lyman-alpha system, which are presumed to originate within the interstellar media of high-redshift galaxies. We propose to study the three dimensional distribution of galaxies around each of these QSOs in an effort to study and characterize the galaxies responsible for this high column density, low ionization absorption. The imaging of damped Lyman-alpha absorbers has been a difficult challenge, even at much lower redshifts, and we do not expect to be able to resolve the absorber from the background QSO with GMOS imaging - we have proposed for higher resolution Hokupa'a + Gemini imaging for that purpose. In this proposal we will image a larger area surrounding the QSOs and obtain optical spectra of all galaxies detected down to a limiting magnitude of R ~ 23.5. These data will identify and separate galaxies which coincidentally lie along the line of sight and are not associated with the damped Lyman-alpha absorbers from those which may be associated in groups or clusters with them. We will also identify, based on the optical spectra plus the infrared - optical colors for those galaxies in both the Hokupa'a and GMOS fields of view, high-redshift galaxy candidates suitable for follow-up near-IR spectroscopy. Our goal is to provide redshifts for all galaxies surrounding Q1331+170 and Q1756+237 in an effort to characterize the potential cluster (and formation) environment of these high-redshift damped Ly-alpha absorbers, two of which appear to have unusually neutral, thereby presumably cool and dusty, interstellar media which mimic the absorption properties of galaxy disks.

GN-2002A-Q-87

Title: The Chemistry of the Extreme Outer Disks of Nearby Spiral Galaxies

Abstract: The history of the chemical enrichment of the outer disks of galaxies is poorly known, despite its importance for understanding galaxy disk formation and the chemical evolution of the Universe through lines of sight to distant objects. Is the metal content of the peripheries of disks the result of a slow continuous star formation process, or have external parts been contaminated primordially by the metals expelled from the massive starbursts during halo/bulge formation? Internal disk dynamics may have historically been even more important, especially if strong radial flows were induced by bars. We propose to use GMOS to measure O/H abundances of the faint HII region populations in the outer disks (R>R_25) of two spiral galaxies, one normal and the other barred to establish the chemical state of the extreme outer regions of galaxy disks in the light of the predictions for the above processes. The primordial pollution scenario predicts a flattening (or even increasing) gradient in the very outer part, while the bar scenario would produce a rather flat distribution in the inner disk, but thereafter a very steep negative gradient in the outermost parts of the disk.

GN-2002A-Q-88

Title: A galaxy census at z~1 in the GOODS/HDF-N region

Abstract: Most magnitude-limited redshift surveys become incomplete at z~1, especially as a function of galaxy type or color. Here we propose a comprehensive GMOS survey of galaxies at z=1.0+/- 0.2, pre-selected via photometric redshifts, in the HDF-N portion of the Great Observatories Origins Deep Survey (GOODS). GOODS unites the deepest observations from space- and ground-based facilities to study the high redshift universe from X-ray through radio wavelengths. Extremely deep SIRTF Legacy observations at 3.6 to 24um will measure rest-frame near-infrared light and redshifted 12um PAH emission at z=1. Together with GMOS emission line measurements, UV to near-IR photometry, radio observations, and existing and planned SCUBA surveys, these data will provide a thorough census of the stellar content and star formation rate distributions in galaxies when the universe was half its present size and ~40% its present age. 1Msec Chandra imaging measures AGN activity down to low-level Seyfert luminosities, and several HST/ACS "Treasury" proposals have been submitted to observe galaxy morphologies over this region. All GOODS SIRTF and ground-based data, as well as Chandra and proposed HST observations are non-proprietary, enabling a wide range of community research activities.

GN-2002A-Q-89

Title: A GMOS survey of the Coma cluster

Abstract: The Coma cluster at a redshift of 0.024 is one of the nearest rich clusters of galaxies. Most studies of high redshift galaxies and clusters use the Coma cluster as low redshift comparison cluster. Therefore knowledge of the properties of this cluster and the galaxies in it has far-reaching importance for our interpretation of high redshift data and our understanding of how galaxies and clusters evolve. We propose to use GMOS on Gemini-North to obtain very high S/N (50-100 per A) spectra of bright galaxies (Btotal<16.3 mag) in the cluster, and modest S/N (~10 per 5A) spectra of faint galaxies (Btotal=18.5-21.5mag). For the bright cluster members the spectra will be used for high accuracy determination of line indices and central velocity dispersions, from which the mean ages and metallicities, and the masses can be derived. For the faint galaxies we will determine redshifts to identify the cluster members, and use the data in our on-going study of the faint end of the galaxy luminosity function. This project is designed to be a backup program for GMOS and to take full advantage of GMOS when observing conditions are not optimal. The observations can be carried out in very poor seeing, up to 1 mag of cloud extinction and during grey time. Past experience has shown a need for programs in the queue that can be executed during these rather poor conditions, and at the same time produce good quality science data.

Last update February 15, 2002; Phil Puxley