NOAO >   Observing Info >   Approved Programs >   2016A-0428

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Program Information for 2016A-0428


PI: Gendtih Sardane, U. of Pittsburgh, gms48@pitt.edu
Address: Department of Physics and Astronomy, 100 Allen Hall, Pittsburgh, PA, 15260 USA

CoI: David Turnshek, U. of Pittsburgh
CoI: Sandhya Rao, U. of Pittsburgh

Title: Mapping cool, metal-rich gas around z < 0.08 galaxies

Abstract: During Semester 2014B and 2015A we obtained GMOS-N queue observations to obtain redshifts of candidate galaxies in order to identify galaxies associated with a sample of rare gaseous regions with redshifts z < 0.08. Our goal was to identify all galaxies down to SDSS r-band luminosity of 0.01L* in the vicinity of CaII absorbing regions seen in background quasar spectra. The presence of CaII absorption is indicative of cool neutral gas that may contain molecules and dust. Consequently, the study of the association between cool, metal-rich gas and galaxies down to very low luminosity will lead to important constraints on the overall existence and extent of cool gas in the regions around galaxies, which in turn constrains models of inflows, outflows, star formation, feedback, and chemical enrichment. This program is unique among those aimed at investigating the association between intervening quasar absorbers and galaxies. Unlike more common UV resonance lines, the CaII doublet is found at optical wavelengths. Therefore, although CaII absorption is rare, it is possible to search for it in huge numbers of optical SDSS quasar spectra and then use the results to perform follow-up studies at very low redshift, in this case at z < 0.08. Our program will find galaxies, including very faint dwarfs, within ~ 100 kpc of the quasar sightlines, enabling us to constrain just how far these gaseous regions are from galaxies. A common criticism of this type of work is that a galaxy could be hidden under a quasar's PSF; however, due to the low absorber redshift values, interference from the glare of the quasar will be negligible. We have one remaining but very interesting field. It showed no candidate galaxies down to 0.01L* in the SDSS images. A GMOS-N pre-image shows galaxies which would be well below 0.01L*. We request 4 hours of GMOS-N time to observe this one remaining field in Semester 2016A and finish our program.

Program Type: Standard/Extragalactic

Scheduled Nights:
Run 1 (2016A):  GEM-NQ/GMOSN -- 4hrs band 1 (GN-2016A-Q-11)


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



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