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