NOAO >   Observing Info >   Approved Programs >   2012B-0337

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Proposal Information for 2012B-0337


PI: Adam Myers, University of Wyoming, geordiemyers@gmail.com
Address: Physics Department, 1000 E. University, Dept. 3905, Laramie, WY 82071, USA

CoI: J. Xavier Prochaska, UCO/Lick Observatory
CoI: Joseph Hennawi, Max-Planck-Institut fuer Astronomie
CoI: Kate Rubin, Max-Planck-Institut fuer Astronomie

Title: Characterizing the Circumgalactic Medium of Low and High Mass Galaxies with Close Quasar Pairs

Abstract: We have mined the SDSS and discovered a sample of rare close QSO pairs at z=2-4 with small transverse separations 30-300 \rm kpc (3-30\arcsec). These unique sightlines offer the first constraints on the physical state of the circumgalactic medium (CGM) of z>2 galaxies hosted by low-mass (\lesssim10^11\msol) and very high-mass (\gtrsim10^13\msol) dark matter halos. Low-mass halos are traced by intervening damped Ly(alpha) absorption (DLA) in one of the sightlines, such that the neighboring sightline probes the CGM of the DLA-galaxy. Similarly, with projected QSO pairs, absorption in the \emphbackground QSO spectra encodes information about the CGM of the \emphforeground QSOs, i.e., the signposts for massive galaxies. We propose to continue our program, successfully initiated in 2012A, to obtain a statistical sample (~40) of spectra with Gemini/GMOS-N and GMOS-S to measure cool gas kinematics, %abundances, and cold gas masses, spatial distribution, and covering fraction to distances < 300 kpc. These observations will provide %a direct test of the cosmological `cold accretion' picture new constraints on the cool gas supply and the physical effects of feedback around both low-mass galaxies and massive QSO hosts. This program is supplemented by collaborations with groups performing `zoom-in' simulations of galactic halos that resolve key physical processes in the CGM.


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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