Gemini e-Newscast #35 -- December 21, 2011by xzhang
1. Record-Breaking Black Holes
Nicholas McConnell (University of California at Berkeley) and collaborators have measured the most massive black holes in the cosmic neighborhood. These are the central black holes of NGC 3842 and NGC 4889, and each has a mass close to 10^10 solar masses. The host galaxies are the brightest cluster galaxies of Abell 1367 and the Coma cluster (Abell 1656). The results lie systematically above the standard relation between black hole mass and stellar velocity dispersion over intermediate mass ranges. With few examples at the high-mass end, it is unclear whether this is just scatter or a systematic trend. The essential data included observations using the Integral Field Unit (IFU) of GMOS on Gemini North, in excellent seeing to resolve stellar kinematics on angular scales of 0.4 arcseconds. These data, combined with similar observations from the Keck 2 telescope, observations of the galaxies' outskirts from McDonald Observatory, and detailed modeling that includes the dark matter halo, yield the black hole masses. The full results are published in Nature (2011 480 215), with a feature story in the upcoming issue of the GeminiFocus newsletter.
NGC 2442 observed with FLAMINGOS-2, with individual observations of 3 to 5 minutes in J, H, and K filters.
2. FLAMINGOS-2 and GeMS Updates
Instrument commissioning continues at Gemini South. For FLAMINGOS-2, the December run represented the return to on-sky commissioning following an extensive period of laboratory work to improve reliability and stability and to install a new detector. See Figure 2 for a recent image. The current goal is to call for system verification proposals in mid-January for programs to be executed in March (for imaging and longslit observations) and July (for multi-object spectroscopy).
The Gemini Multi-Conjugate Adaptive Optics System (GeMS) team completed two runs at the end of this year, one concentrating on the laser and one concentrating on Canopus, the adaptive optics bench. There is more work to do during the first half of 2012, starting with attention to the Gemini South Adaptive Optics Imager (GSAOI).
3. Design Studies for GHOS
Conceptual Design studies have started for the Gemini High-Resolution Optical Spectrograph (GHOS), a proposed next-generation instrument for Gemini. Three strong teams are doing studies, led by the Australian Astronomical Observatory, University of Colorado at Boulder, and the Herzberg Institute of Astrophysics. These studies will be complete in 6 months, providing competitive plans for further design and build of the instrument. The spectrograph, if built, would be expected to have resolution R~40,000, with simultaneous coverage over wavelengths from 370 to 1000 nm, useful for a range of scientific pursuits by the Gemini community.
Best wishes for a healthy new year, from all of us at Gemini!
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