The Coevolution of Nuclear Star Clusters, Massive Black Holes, and Their Host Galaxies

Antonini, Fabio; Barausse, Enrico; Silk, Joseph

doi:10.1088/0004-637x/812/1/72

Cited by 181 publications

(220 citation statements)

References 139 publications

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“…Including (the bulges of) spirals in our reference sample of ellipticals and lenticulars (that of Savorgnan et al 2016) confirms and extends our results. In this context it is no longer meaningful, at least within the biased samples, to look for outliers in the observed M bhMstar relation, such as "pseudo-bulges" (e.g., , or examine whether bulge or total luminosity is a better predictor of M bh (e.g., Marconi & Hunt 2003;Häring & Rix 2004;Läsker et al 2014), or consider the connection to nuclear star clusters only in terms of stellar mass (e.g., Antonini et al 2015;Georgiev et al 2016). Our Monte Carlo results constrain the normalization of the intrinsic black hole-galaxy scaling relations to be a factor of 3 lower than current estimates, in terms of velocity dispersion, and up to a factor of ∼ 50 − 100 lower when expressing black hole masses as a function of stellar mass (e.g., Figure 3).…”

Section: Direct Implications Of the Bias In The Observed Scaling Relamentioning

confidence: 99%

Selection bias in dynamically measured supermassive black hole samples: its consequences and the quest for the most fundamental relation

Shankar¹,

Bernardi²,

Sheth³

et al. 2016

Mon. Not. R. Astron. Soc.

246

369

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We compare the set of local galaxies having dynamically measured black holes with a large, unbiased sample of galaxies extracted from the Sloan Digital Sky Survey. We confirm earlier work showing that the majority of black hole hosts have significantly higher velocity dispersions σ than local galaxies of similar stellar mass. We use Monte-Carlo simulations to illustrate the effect on black hole scaling relations if this bias arises from the requirement that the black hole sphere of influence must be resolved to measure black hole masses with spatially resolved kinematics. We find that this selection effect artificially increases the normalization of the M bh -σ relation by a factor of at least ∼ 3; the bias for the M bh -M star relation is even larger. Our Monte Carlo simulations and analysis of the residuals from scaling relations both indicate that σ is more fundamental than M star or effective radius. In particular, the M bh -M star relation is mostly a consequence of the M bh -σ and σ-M star relations, and is heavily biased by up to a factor of 50 at small masses. This helps resolve the discrepancy between dynamically-based black hole-galaxy scaling relations versus those of active galaxies. Our simulations also disfavour broad distributions of black hole masses at fixed σ. Correcting for this bias suggests that the calibration factor used to estimate black hole masses in active galaxies should be reduced to values of f vir ∼ 1. Black hole mass densities should also be proportionally smaller, perhaps implying significantly higher radiative efficiencies/black hole spins. Reducing black hole masses also reduces the gravitational wave signal expected from black hole mergers.

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Section: Direct Implications Of the Bias In The Observed Scaling Relamentioning

confidence: 99%

Selection bias in dynamically measured supermassive black hole samples: its consequences and the quest for the most fundamental relation

Shankar¹,

Bernardi²,

Sheth³

et al. 2016

Mon. Not. R. Astron. Soc.

246

369

View full text Add to dashboard Cite

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“…The minus sign in the expression of the inflow 3 An additional caveat is related to a putative stellar spike which might have formed jointly with a DM spike in the adiabatic formation scenario. However, this would strongly rely on the existence of a nuclear star cluster (NSC), which in the most accepted view is formed by merging globular clusters [32]. Unlike the Milky Way, M87 is actually not an optimal candidate for such mergers, due to the large velocity dispersion induced by the very massive central BH.…”

Section: B Electron Propagation In the Presence Of Advectionmentioning

confidence: 99%

Unique probe of dark matter in the core of M87 with the Event Horizon Telescope

et al. 2017

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We demonstrate the unprecedented capabilities of the Event Horizon Telescope (EHT) to image the innermost dark matter profile in the vicinity of the supermassive black hole at the center of the M87 radio galaxy. We present the first model of the synchrotron emission induced by dark matter annihilations from a spiky profile in the close vicinity of a supermassive black hole, accounting for strong gravitational lensing effects. Our results show that the EHT should readily resolve dark matter spikes if present. Moreover, the photon ring surrounding the silhouette of the black hole is clearly visible in the spike emission, which introduces observable small-scale structure into the signal. We find that the dark matter-induced emission provides an adequate fit to the existing EHT data, implying that in addition to the jet, a dark matter spike may account for a sizable portion of the millimeter emission from the innermost (subparsec) region of M87. Regardless, our results show that the EHT can probe very weakly annihilating dark matter. Current EHT observations already constrain very small cross sections, typically down to a few 10 −31 cm 3 s −1 for a 10 GeV candidate, close to characteristic values for p-wave-suppressed annihilation. Future EHT observations will further improve constraints on the DM scenario. PACS numbers: 95.35.+d, 95.55.Br

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“…An alternative formation channel is in situ growth through star formation (Milosavljević 2004;Antonini et al 2015). It is not clear which of these two mechanisms dominates NSC formation, and the data is often consistent with contributions from both channels (Leigh et al 2012;Antonini et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Formation of Massive Black Holes in Galactic Nuclei: Runaway Tidal Encounters

Stone

Küpper

Ostriker

2017

Mon. Not. R. Astron. Soc.

109

115

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Nuclear star clusters (NSCs) and supermassive black holes (SMBHs) both inhabit galactic nuclei, coexisting in a range of bulge masses, but excluding each other in the largest or smallest galaxies. We propose that the transformation of NSCs into SMBHs occurs via runaway tidal captures, once NSCs exceed a certain critical central density and velocity dispersion. The bottleneck in this process, as with all collisional runaways, is growing the first e-fold in black hole mass. The growth of a stellar mass black hole past this bottleneck occurs as tidally captured stars are consumed in repeated episodes of mass transfer at pericenter. Tidal captures may turn off as a growth channel once the black hole reaches a mass ∼ 10 2−3 M , but tidal disruption events will continue and appear capable of growing the seed SMBH to larger sizes. The runaway slows (becomes sub-exponential) once the seed SMBH consumes the core of its host NSC. While the bulk of the cosmic mass density in SMBHs is ultimately produced (via the Soltan-Paczynski argument) by episodic gaseous accretion in very massive galaxies, the smallest SMBHs have probably grown from strong tidal encounters with NSC stars. SMBH seeds that grow for a time t entirely through this channel will follow simple power law relations with the velocity dispersion, σ, of their host galaxy. In the simplest regime it is M • ∼ σ 3/2 M t/G ∼ 10 6 M (σ/50 km s −1 ) 3/2 (t/10 10 yr) 1/2 , but the exponents and prefactor can differ slightly depending on the details of loss cone refilling. Current tidal disruption event rates predicted from this mechanism are consistent with observations.

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The Coevolution of Nuclear Star Clusters, Massive Black Holes, and Their Host Galaxies

Cited by 181 publications

References 139 publications

Selection bias in dynamically measured supermassive black hole samples: its consequences and the quest for the most fundamental relation

Selection bias in dynamically measured supermassive black hole samples: its consequences and the quest for the most fundamental relation

Unique probe of dark matter in the core of M87 with the Event Horizon Telescope

Formation of Massive Black Holes in Galactic Nuclei: Runaway Tidal Encounters

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