NOAO >   Observing Info >   Approved Programs >   2014B-0253

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Proposal Information for 2014B-0253


PI: Tahlia DeMaio, University of Florida, demaio@astro.ufl.edu
Address: Astronomy Department, 211 Bryant Space Science Center, University of Florida, Gainesville, FL 32607, USA

CoI: Anthony Gonzalez, University of Florida
CoI: John Mulchaey, Carnegie Institution for Science
CoI: Ann Zabludoff, University of Arizona, Steward Observatory
CoI: Dennis Zaritsky, University of Arizona, Steward Observatory

Title: Baryon Fractions in Galaxy Groups

Abstract: We propose to use GMOS on Gemini South to obtain spectroscopic redshifts for galaxies in three galaxy groups at <z>=0.37 to complement our HST-based program to determine total stellar mass content and baryon fractions in a statistical sample of X-ray galaxy groups and clusters at 0.2<z<0.9. Our previous work with a low redshift sample of clusters shows that the fraction of baryonic content in the stellar mass is higher in low mass groups than in massive clusters. Additionally, the brightest cluster galaxy and intracluster light (ICL) can constitute ~50% of the stellar mass in group mass halos. Because the ICL is thought to form at late times (z<1) our higher redshift sample will allow us to constrain when the majority of ICL is in place and the mass dependence of ICL assembly. The field of view of GMOS enables a robust stellar mass measurement out to the virial radii of these groups, making GMOS an ideal instrument for this program.


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