Active black holes and the evolution of their host galaxies

Details Active black holes and the evolution of their host galaxies Active black holes and the evolution of their host galaxies

Nov 2005

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005phdt.........5w&link_type=abstract

Ph.D. dissertation.United States -- Connecticut: Yale University; 2005. Publication Number: AAT 3169019.150 pages; DAI-B

Other

1

Black Holes, Galaxies, Active Galactic Nuclei

Scientific paper

Black hole mass, along with mass accretion rate, is a fundamental property of active galactic nuclei (AGNs). We collect and estimate black hole mass for a large sample of ~500 AGNs, and investigate the relation of AGN activity to black hole mass. For a subsample of 39 AGNs at z < 0.6, we measure and collect stellar velocity dispersion, estimate black hole mass, and invesigate the evolution of host galaxies.
We compare black hole mass estimates generated by different methods and find, for individual objects, a scatter as high as a couple of orders of magnitude. The less direct the method, the larger the discrepancy with other estimates, probably due to the large scatter in the underlying correlations assumed.
In contrast to other studies, we find no significant correlation of black hole mass with AGN luminosity, other than those induced by circular reasoning in the estimation of black hole mass. For any given black hole mass, there is a range in Eddington ratio of up to 3 orders of magnitude, with the Eddington limit as an approximate upper envelope to the distribution of luminosities. The black hole mass of radio-loud and radio-quiet AGNs span the same large range, 10 6 - 10 10 M [Special characters omitted.] , suggesting radio loudness in AGNs does not depend on black hole mass.
The black hole mass range for different BL Lac spectral types, defined by X-ray to radio flux ratio, is similar, 10 7 [Special characters omitted.] M BH / M [Special characters omitted.] 4 x 10 9 . Neither X-ray or radio luminosity correlates with black hole mass. Low-frequency-peaked BL Lac objects have higher Eddington ratios on average, because of either more beaming or larger intrinsic power. For the black hole mass range 3 x 10 7 [Special characters omitted.] M * [Special characters omitted.] 10 9 , the radio luminosity of BL Lac objects and flat-spectrum radio quasars spans over 4 orders of magnitude, with BL Lac objects being low-power AGNs.
BL Lac object host galaxies and radio galaxies seem to lie on the same fundamental plane as normal galaxies. Comparing the mass-to-light ratio evolution in the observed-frame with our population synthesis models, we find that single burst star formation models with z form = [Special characters omitted.] are consistent with the observations. After K -correction using our z form = 1.4 model, we estimate the intrinsic mass-to-light ratio evolution in the Cousins R band, D log ( M / L )/D z = -0.502, consistent with that of normal early-type galaxies. The normality of AGN host galaxies supports the hypothesis that AGNs are a transient phase in the evolution of most or all galaxies.

Affiliated with

Also associated with

No associations

Rating

Active black holes and the evolution of their host galaxies 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 Active black holes and the evolution of their host galaxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Active black holes and the evolution of their host galaxies will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1652375