the good nicmos survey (gns): observing massive galaxies at z > 2
DESCRIPTION
The GOOD NICMOS Survey (GNS): Observing Massive Galaxies at z > 2. Christopher J. Conselice (University of Nottingham) with Asa Bluck, Ruth Gruethbacher, Amanda Bauer, Fernando Buitrago (Nottingham) + others. - PowerPoint PPT PresentationTRANSCRIPT
The GOOD NICMOS Survey (GNS): Observing Massive Galaxies at z > 2
Christopher J. Conselice (University of Nottingham)
with Asa Bluck, Ruth Gruethbacher, Amanda Bauer, Fernando Buitrago (Nottingham) + others
Motivation: Nearly all massive galaxies are formed by z~1 - 1.5
Cole et al. (2001) z~0 comparison
Results from PalomarObservatory Wide-FieldInfrared Survey (POWIR)+DEEP2 Redshifts
(Conselice et al. 2007)
Massive galaxies must form at > 1.5
Millennium simulation
Prediction for log M > 11.5
Prediction for 11 < log M < 11.5
Vast under prediction in models compared to observations
Conselice et al. (2007)
Also, there are too many massive galaxies in comparison to models
Can detect log M = 9.5 galaxies to z = 3
GOODS z GNS H
log M > 11
Size evolution for GNS galaxies
Buitrago et al. (2008), ApJ, 687, 61
ALL massive galaxies at z > 2 are compact
Galaxy sizes continue to decrease at higher redshifts
Buitrago et al. 2008Major mergers cannot explain
What is the role of AGN in galaxy formation?
Can investigate with our sample using X-ray selected AGN Hosted by log M > 11 galaxies at 0.4 < z < 6 within the DEEP2/Palomar and GNS fields
Method - find X-ray luminous AGN that are more luminous thanL_X > 2.35 * 10^43 erg/s - create volume limited samples
Using X-ray luminosities to calculate the black hole mass
Co-evolution of black hole mass and galaxy mass
If we assume that average black hole eta efficiency is the same at low and high redshift, or increasing with higher redshift then
M_*/M_bh > 600 (compared to 1000 in local universe)
Bluck, Conselice et al. (2010) in prep
Haring & Rix 04
Can place constrainson time-scales for AGNactivity based on M_*M_BH relation
Rate = life-time/f_AGN
Reveals that > 1/4 of massive galaxies havean AGN > 10^43 erg/sat 0.4 < z < 3
The star formation rates as a function of stellar mass
Galaxies with masseslog M > 11 willroughly double instellar mass due tostar formation
Ave. starformationrate for log M > 11galaxies is roughlyconstant at 1.5 < z < 3rhen declines at z < 1.5
Mass added from SF ~ Mass from major merging
What factors drive the evolution of galaxies?
Relation betweenenvironment and color at z < 1 fora log M > 10.25sample
Much stronger relationbetween color andstellar mass of thegalaxy
Galaxy properties donot strongly dependon the total environmentas measured by halo massof group/cluster
See at higher redshiftsas well for galaxieswith log M > 9.5
Holds up to z =3
Gruethbacher, Conselice et al. (2010) in prep
Individual galaxy massis most important propertyfor determining its formation history
Summary
1. Very deep NICMOS/HST imaging (GNS) to study galaxies at z > 2 to connect with galaxies at z < 1.5 with previous deep NIR surveys
2. Examination of the major merger history, the AGN history and how enviroment vs. mass effects the formation of galaxies 3. Massive galaxies become more compact at progressively higher redshifts and over 1/4th of massive galaxies at z < 3 have hosted an AGN. Log M > 11 galaxies double in mass due to star formation over ~2 Gyr period 1.5 < z < 3, similar increase due to major mergers
4. Galaxy stellar mass most important driver of galaxy formation up to z=3