Report on NIRSPEC observing nights of 20-22 November 2001

Summary Report on the three nights of Gemini/ NIRSPEC 2001B time

Observing at Keck II using NIRSPEC was carried out on the three nights of 20, 21, and 22 November 2001 (UT) on behalf of the Gemini community. Skies were photometric during the entire period. The seeing was below average on the first night (typically 0.8" at K) and improved to 0.5-0.6" at K on the following nights.

The Keck II telescope pointed and tracked very well during the three nights. During much of the time NIRSPEC behaved well; however there were a number of problems that slowed data taking, or had deleterious effect on data. These were: (1) about 8 server crashes, which interrupted exposures and usually required complete run-downs/ups of the software, typically losing 15-30 minutes per event; (2) water ice on one or more NIRSPEC optical surfaces, which produced variable attenuation along the slit at 2.9-3.2 microns; and (3) intermittent electronic pickup on one or more of the quadrants of the array, which manifested itself as rows of enhanced or reduced signal. The latter in particular is a non-trivial data reduction problem for faint targets observed at short IR wavelengths.

Programs that were attempted are listed below, along with brief statements of the results. Within the next two weeks we will be making the data available to the PI's of the proposals.

152s_e (He 10830 in pms objects - Edwards): echelle spectra obtained on night 3; line easy to see in bright objects, some faint object spectra affected by residuals and eletronic noise.

154t_g (Hydrocarbons in Titan - Geballe): echelle spectra obtained on night 2; exposure times slightly less than requested; s/n degraded by ice absorption in instrument).

156t_g (CH overtone- Geballe): spectra obtained on night 1.

157scb (16O/17O in giants - Balachandran): echelle spectra obtained on night 2; airmass matches not as good as hoped, but should be OK.

158bjh (UIR bands in PPN - Hrivnak): grating spectra of most sources obtained on night 2 and night 3; short wavelength region degraded by water ice absorption.

159k_n (methane in a T0 dwarf - Noll): grating spectrum obtained on night 3; shorter exposure time than estimated but desired s/n achieved except at short wavelength end due to ice absorption.

160j_m (O in metal poor stars - Melendez): echelle spectrum obtained on night 1.

162j_n (Brown dwarfs and superplanets - Najita): grating spectra of the two brighter objects obtained on night 1.

164kcr (Damped Ly absorber - Roth) - quick look grating spectra taken at one slit position and at nearby quasar on night 3.

165s_l (brown dwarf in a CV - Littlefair) - attempted on night 3; target found to be much too faint to see spectral features in required time interval; thus only a small amount of data were obtained. Some confusion because a brighter object at J is located only 4" east.

168mvm (OIII in lensed galaxy - Villar-Martin): grating spectra obtained on night 1; K band spectra looks very nice although exposure time is shorter than requested.

170esp (Pa alpha in young AGN - Perlman): grating spectra obtained on night 3.

175tsb (Seyfert nucleus kinematics - Storchi-Bergmann): grating spectrum of one target obtained on night 2.

176a_c (Mg II QSO absorber - Crotts): echelle spectra obtained on nights 2 and 3; some data compromised by pattern noise.

177x_f (Mg II z=4.7 quasar - Fan): grating spectrum obtained on night 3.

179gps (ERO - Smith): grating spectrum obtained on night 2, in part compromised by electronic pattern noise.

Last update November 26, 2001; Tom Geballe