On the cosmological evolution of the black hole-host galaxy relation in quasars
Abstract
Quasars are useful tracers of the cosmological evolution of the black hole mass-galaxy relation. We compare the expectations of semi-analytical models (SAMs) of galaxy evolution to the largest available data sets of quasar host galaxies out to z≃ 3.
Observed quasar hosts are consistent with no evolution from the local MBH-Lhost relation and suggest a significant increase of the mass ratio ? from z= 0 to 3. Taken at face value, this is totally at odds with the predictions of SAMs, where the intrinsic Γ shows little evolution and quasar host galaxies at high redshift are systematically overluminous (and/or have an undermassive BH). However, since quasars preferentially trace very massive black holes (109-1010 M⊙) at the steep end of the luminosity and mass function, the ensuing selection biases can reconcile the present SAMs with the observations. A proper interpretation of quasar host data thus requires the global approach of SAMs so as to account for statistical biases.- Publication:
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Monthly Notices of the Royal Astronomical Society
- Pub Date:
- February 2012
- DOI:
- 10.1111/j.1365-2966.2011.20086.x
- arXiv:
- arXiv:1110.6067
- Bibcode:
- 2012MNRAS.420..732P
- Keywords:
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- galaxies: active;
- galaxies: evolution;
- galaxies: formation;
- galaxies: high-redshift;
- quasars: general;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 14 pages, 10 colour figures. In press on MNRAS