Abstract
We use the science demonstration field data of the Herschel
Astrophysical Terahertz Large Area Survey to study how star formation,
traced by the far-infrared Herschel data, is related to both the
accretion luminosity and redshift of quasars selected from the Sloan
Digital Sky Survey (SDSS) and the 2dF-SDSS luminous red galaxy (LRG) and
Quasar Spectroscopic Catalogue survey. By developing a
maximum-likelihood estimator to investigate the presence of correlations
between the far-infrared and optical luminosities, we find evidence that
the star formation in quasar hosts is correlated with both redshift and
quasar accretion luminosity. Assuming a relationship of the form
LIR∝LθQSO(1
+z)ζ, we find θ= 0.22 ± 0.08 and ζ=
1.6 ± 0.4, although there is substantial additional uncertainty
in ζ of the order of ±1, due to uncertainties in the host
galaxy dust temperature. We find evidence for a large intrinsic
dispersion in the redshift dependence, but no evidence for intrinsic
dispersion in the correlation between LQSO and
LIR, suggesting that the latter may be due to a direct
physical connection between star formation and black hole accretion.
This is consistent with the idea that both the quasar activity and star
formation are dependent on the same reservoir of cold gas, so that they
are both affected by the influx of cold gas during mergers or heating of
gas via feedback processes. Herschel is an ESA space observatory with
science instruments provided by European-led Principal Investigator
consortia and with important participation from NASA.
Original language | English |
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Pages (from-to) | 13-21 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 416 |
DOIs | |
Publication status | Published - 1 Sep 2011 |