Tracing the Accretion History of the Universe by stacking X-rays from Red Galaxies in the NDWFS Kate Brand, NOAO, Tucson A. Dey, B. Jannuzi, M. Brown, J. Najita, C. Kochanek, C. Watson, D. Fabricant, G. Fazio, W. Forman, P. Green, C. Jones, A. Kenter, S. Murray, A. Vikhlinin, B. McNamara, J. Shields, M. Rieke AAS, Denver, June 2004

The NDWFS / XBoÖtes fields

Summary Stacking analysis of X-rays from optically selected galaxies to determine mean X-ray properties and how this evolves. Wide field / deep multi-band optical data AGN / star formation.

The NDWFS red galaxy population (Brown et al. 2003) 3316 red galaxies in 1.4 deg2 region selected by model SED fitting to photometric data Photometric redshifts, z= 0.3-0.9 Same evolution corrected absolute magnitude distribution over all redshifts (MR < -20.5) -> tracing same population

The stacked X-ray images

Evolution of X-ray Luminosity with Redshift TOTAL HARD SOFT

Future Work The full 9 deg2 -> ~ 7 x number of objects -> better number statistics Smaller errors Divide population into sub-populations Mean X-ray spectra Bimodality in number counts Stacking of X-rays in different optical populations - AGN / Star formation Multi-wavelength data - deep radio / FIR - star formation rates

Extraction radius / off-axis distance

Results Redshift No. galaxies X-ray Counts (bkgd) X-ray Flux (bkgd) 10-16 ergs cm-2 s-1 X-ray Luminosity 1042 ergs s-1 0.3-0.5 0.5-10keV 0.5-2keV 2-10keV 1040 149 (26.5) 73 (10.5) 76 (16.0) 2.87±0.23 (0.51) 0.64±0.08 (0.09) 3.80±0.43 (0.80) 0.12 ± 0.01 0.028 ± 0.004 0.15 ± 0.02 0.5-0.7 1271 116 (32.25) 52 (13.25) 64 (19.0) 1.83±0.17 (0.51) 0.37±0.05 (0.09) 2.62±0.32 (0.77) 0.17 ± 0.02 0.036 ± 0.007 0.24 ± 0.05 0.7-0.9 1005 95 (30.75) 53 (12.5) 42 (18.25) 1.89±0.19 (0.61) 0.48±0.07 (0.11) 2.17±0.34 (0.94) 0.32 ± 0.06 0.093 ± 0.019 0.31 ± 0.10

Number counts

Tau distribution

MR distribution