Black hole masses in active galaxies

Barth, Aaron J.

doi:10.1017/s1743921304001334

Cited by 4 publications

(2 citation statements)

References 30 publications

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“…This is in very good agreement with the shape of the M bh −σ relation determined recently from an observational census (an HST ACS survey) of low mass galaxies in the Virgo cluster reported by Ferrarese et al (2006). While current data in the low mass regime are scant (Barth 2004;Greene & Ho 2007;Kormendy & Bender 2011), future instruments and surveys are likely to probe this region of parameter space with significantly higher sensitivity.…”

Section: Discussionsupporting

confidence: 89%

The formation and evolution of massive black hole seeds in the early Universe

Natarajan

2011

Fluid Flows to Black Holes

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Tracking the evolution of high redshift seed black hole masses to late times, we examine the observable signatures today. These massive initial black hole seeds form at extremely high redshifts from the direct collapse of pre-galactic gas discs. Populating dark matter halos with seeds formed in this fashion, we follow the mass assembly history of these black holes to the present time using a Monte-Carlo merger tree approach. Utilizing this formalism, we predict the black hole mass function at high redshifts and at the present time; the integrated mass density of black holes in the Universe; the luminosity function of accreting black holes as a function of redshift and the scatter in observed, local M bh − σ relation. Comparing the predictions of the 'light' seed model with these massive seeds we find that significant differences appear predominantly at the low mass end of the present day black hole mass function. However, all our models predict that low surface brightness, bulge-less galaxies with large discs are least likely to be sites for the formation of massive seed black holes at high redshifts. The efficiency of seed formation at high redshifts has a direct influence on the black hole occupation fraction in galaxies at z = 0. This effect is more pronounced for low mass galaxies. This is the key discriminant between the models studied here and the Population III remnant 'light' seed model. We find that there exists a population of low mass galaxies that do not host nuclear black holes. Our prediction of the shape of the M bh − σ relation at the low mass end and increased scatter has recently been corroborated by observations.

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Section: Discussionsupporting

confidence: 89%

The formation and evolution of massive black hole seeds in the early Universe

Natarajan

2011

Fluid Flows to Black Holes

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“…In any given galaxy, a BH detection can be roughly labeled in terms of r G , the radius of the sphere of influence within which the BH dominates the gravitational potential of its host galaxy. However, it is easily seen that for a 10 8 M ⊙ , at a distance of 20 Mpc, r G is only 0.11 arcsec (e.g., Barth, 2004), which proves that reliable direct dynamical BH mass measurements can only be safely obtained in nearby galaxies. In particular, the presence of BHs in inactive galaxies is tested through the velocity dispersion of stars, water masers, and gas (see Ferrarese and Ford 2005).…”

Section: Introductionmentioning

confidence: 98%

The demography of supermassive black holes: Growing monsters at the heart of galaxies

Shankar

2009

New Astronomy Reviews

104

119

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Supermassive black holes (BHs) appear to be ubiquitous at the center of all galaxies which have been observed at high enough sensitivities and resolution with the Hubble Space Telescope. Their masses are found to be tightly linked with the masses and velocity dispersions of their host galaxies. On the other hand, BHs are widely held to constitute the central engines of quasars and active galactic nuclei (AGN) in general. It is however still unclear how BHs have grown, and whether they have co-evolved with their hosts. In this Review I discuss how, in ways independent of specific models, constraints on the growth history of BHs and their host galaxies have been set by matching the statistics of local BHs to the emissivity, number density, and clustering properties of AGNs at different cosmological epochs. I also present some new results obtained through a novel numerical code which evolves the BH mass function and clustering adopting broad distributions of Eddington ratios. I finally review BH evolution in a wider cosmological context, connecting BH growth to galaxy evolution.

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POX 52: A Dwarf Seyfert 1 Galaxy with an Intermediate‐Mass Black Hole

Barth

Rutledge

et al. 2004

ApJ

Self Cite

276

323

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We describe new optical images and spectra of POX 52, a dwarf galaxy with an active nucleus that was originally detected in the POX objective-prism survey. While POX 52 was originally thought to be a Seyfert 2 galaxy, the new data reveal an emission-line spectrum very similar to that of the dwarf Seyfert 1 galaxy NGC 4395, with broad components to the permitted line profiles, and we classify POX 52 as a Seyfert 1 galaxy.The host galaxy appears to be a dwarf elliptical, and its brightness profile is best fit by a Sérsic model with an index of 3.6 ± 0.2 and a total magnitude of M V = −17.6. Applying mass-luminosity-linewidth scaling relations to estimate the black hole mass from the broad Hβ linewidth and nonstellar continuum luminosity, we find M BH ≈ 1.6 × 10 5 M ⊙ . The stellar velocity dispersion in the host galaxy, measured from the Ca II λ8498, 8542 Å lines, is 36 ± 5 km s −1 , also suggestive of a black hole mass of order 10 5 M ⊙ . Further searches for active nuclei in dwarf galaxies can provide unique constraints on the demographics of black holes in the mass range below 10 6 M ⊙ .

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Black hole masses in active galaxies

Abstract: Abstract. This contribution reviews two topics of current interest in the study of black hole demographics in active galaxies: Can the stellar velocity dispersions of quasar host galaxies be measured? And can we constrain the black hole mass function below 10 6 M ?

Cited by 4 publications

References 30 publications

The formation and evolution of massive black hole seeds in the early Universe

The formation and evolution of massive black hole seeds in the early Universe

The demography of supermassive black holes: Growing monsters at the heart of galaxies

POX 52: A Dwarf Seyfert 1 Galaxy with an Intermediate‐Mass Black Hole

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