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 dataPhotometric redshifts, z= 0.3-0.9Same 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

SOFT

HARD TOTAL

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 0.5-10keV

0.5-2keV

2-10keV

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 0.5-10keV

0.5-2keV

2-10keV

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