Astronomy and Astrophysics – Astrophysics – Cosmology and Extragalactic Astrophysics
Scientific paper
2010-07-09
Astronomy and Astrophysics
Astrophysics
Cosmology and Extragalactic Astrophysics
15 pages, 13 figures; submitted to MNRAS
Scientific paper
We find that X-ray sources in the Extended Chandra Deep Field South are strongly spatially correlated with LABOCA 870 micron sources. We investigate the dependence of this correlation on X-ray flux, hardness ratio and column density, finding that specifically faint and absorbed X-ray sources are significant sub-mm emitters. In the X-ray source redshift subsample we confirm the previous result that higher luminosity sources (L_X>10^44 ergs/s) have greater 870um fluxes but we also find that this subsample selects against absorbed sources, faint in X-ray flux. Overall, we find that X-ray sources contribute 1.5 \pm 0.1 Jy/deg^2 to the sub-mm background, ~3% of the total, in agreement with the prediction of an obscured AGN model which also gives a reasonable fit to the bright sub-mm source counts. This non-unified model also suggests that when Compton-thick, X-ray-undetected sources are included, then the fractional AGN contribution to the sub-mm background would rise from ~3% to a total of 25-40%, although in a unified model the AGN contribution would only reach ~13%, because the sub-mm flux of the X-ray sources is then more representative of the whole AGN population. Measurements of the dependence of sub-mm flux on X-ray flux, luminosity and column density all agree well with the predictions of the non-unified AGN model. Heavily absorbed, X-ray-undetected AGN could explain the further cross-correlation we find between sub-mm sources and z > 0.5 red galaxies. We conclude that sub-mm galaxies may contain the long-sought absorbed AGN population needed to explain the X-ray background.
Hill Michael D.
Shanks Tom
No associations
LandOfFree
The contribution of AGN to the sub-mm population does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The contribution of AGN to the sub-mm population, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The contribution of AGN to the sub-mm population will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-299812