Publication Date:
2015-04-16
Description:
We present the first cross-correlation measurement between Sloan Digital Sky Survey type 1 quasars and the cosmic infrared background (CIB) measured by Herschel . The quasars cover the redshift range 0.15 〈 z 〈 3.5 where most of the CIB originates. We detect the sub-millimetre emission of the quasars, which dominates on small scales, and correlated emission from dusty star-forming galaxies (DSFGs) dominant on larger scales. The mean flux of the Data Release 7 (DR7) quasars (median redshift 〈 z 〉 = 1.4) is 11.1, 7.1 and 3.6 mJy at 250, 350 and 500 μm, respectively, while the mean flux of the DR9 quasars (〈 z 〉 = 2.5) is 5.7, 5.0 and 1.8 mJy at 250, 350 and 500 μm, respectively. Assuming a modified blackbody spectral energy distribution with a power law in the mid-infrared, we infer that the mean infrared luminosity of the DR7 and DR9 quasars is 10 12.4 and 10 12.8 L , respectively. The correlated emission arises from DSFGs in the same halo as the quasar (the one-halo term) and DSFGs in separate haloes correlated with the quasar-hosting halo (the two-halo term). Using a simple halo model, we find that most quasars are hosted by central galaxies. The host halo mass scale of the DR7 central and satellite quasars is 10 12.4 ± 0.9 and 10 13.6 ± 0.4 M , respectively. The host halo mass scale of the DR9 central and satellite quasars is 10 12.3 ± 0.6 and 10 12.8 ± 0.4 M , respectively. Thus, the halo environment of the central quasars is similar to that of the most actively star-forming galaxies, which supports the view that dusty starburst and quasar activity are evolutionarily linked.
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
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