scholarly journals Are Nuclear Star Clusters the Precursors of Massive Black Holes?

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Nadine Neumayer ◽  
C. Jakob Walcher
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Star Clusters ◽  
Massive Black Holes ◽  
Massive Galaxies ◽  
Upper Limits ◽  
Nuclear Clusters ◽  
Low Mass ◽  
Nuclear Cluster ◽  
Black Hole Masses

We present new upper limits for black hole masses in extremely late type spiral galaxies. We confirm that this class of galaxies has black holes with masses less than 106M⊙, if any. We also derive new upper limits for nuclear star cluster masses in massive galaxies with previously determined black hole masses. We use the newly derived upper limits and a literature compilation to study the low mass end of the global-to-nucleus relations. We find the following. (1) TheMBH-σrelation cannot flatten at low masses, but may steepen. (2) TheMBH-Mbulgerelation may well flatten in contrast. (3) TheMBH-Sersicnrelation is able to account for the large scatter in black hole masses in low-mass disk galaxies. Outliers in theMBH-Sersicnrelation seem to be dwarf elliptical galaxies. When plottingMBHversusMNCwe find three different regimes: (a) nuclear cluster dominated nuclei, (b) a transition region, and (c) black hole-dominated nuclei. This is consistent with the picture, in which black holes form inside nuclear clusters with a very low-mass fraction. They subsequently grow much faster than the nuclear cluster, destroying it when the ratioMBH/MNCgrows above 100. Nuclear star clusters may thus be the precursors of massive black holes in galaxy nuclei.

scholarly journals Black hole and nuclear cluster scaling relations: Mbh ∝ Mnc2.7±0.7

2014 ◽  
Vol 10 (S312) ◽  
pp. 269-273 ◽  
Author(s):  
Alister W. Graham
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Star Clusters ◽  
Compact Object ◽  
Scaling Relations ◽  
Black Hole Mass ◽  
Massive Black Holes ◽  
Mass Scaling ◽  
Nuclear Cluster ◽  
Evolutionary Growth

AbstractThere is a growing array of supermassive black hole and nuclear star cluster scaling relations with their host spheroid, including a bent (black hole mass)–(host spheroid mass) Mbh–Msph relation and a different (massive compact object mass)–(host spheroid velocity dispersion) Mmco–σ relations for black holes and nuclear star clusters. By combining the observed Mbh ∝ σ5.5 relation with the observed Mnc ∝ σ1.6–2.7 relation, we derive the expression Mbh ∝ Mnc2–3.4, which should hold until the nuclear star clusters are eventually destroyed in the larger core-Sérsic spheroids. This new mass scaling relation helps better quantify the rapid evolutionary growth of massive black holes in dense star clusters, and the relation is consistently recovered when coupling the observed Mnc ∝ Msph0.6–1.0 relation with the recently observed quadratic relation Mbh ∝ Msph2 for Sérsic spheroids.

scholarly journals Formation and Evolution of Massive Black Holes in Star Clusters

2005 ◽  
Vol 13 ◽  
pp. 350-353
Author(s):  
Holger Baumgardt ◽  
Junichiro Makino ◽  
Simon Portegies Zwart
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Initial Conditions ◽  
Star Clusters ◽  
Dynamical Evolution ◽  
Young Star ◽  
Cluster Center ◽  
Massive Black Hole ◽  
Massive Black Holes ◽  
Equilibrium Profile

AbstractWe present results of N-body simulations on the formation of massive black holes by run-away merging in young star clusters and the later dynamical evolution of star clusters containing massive black holes. We determine the initial conditions necessary for run-away merging to form a massive black hole and study the equilibrium profile that is established in the cluster center as a result of the interaction of stars with the central black hole. Our results show that star clusters which contain black holes have projected luminosity profiles that can be fitted by standard King models. The presence of massive black holes in (post-)core collapse clusters is therefore ruled out by our simulations.

scholarly journals Formation of low-spinning 100 M⊙ black holes

2020 ◽  
Vol 640 ◽  
pp. L20
Author(s):  
K. Belczynski ◽  
S. Banerjee
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Gravitational Wave ◽  
Globular Clusters ◽  
Primordial Black Hole ◽  
Massive Black Hole ◽  
Mass Gap ◽  
High Speeds ◽  
Nuclear Clusters ◽  
Nuclear Cluster

Aims. It is speculated that a merger of two massive stellar-origin black holes in a dense stellar environment may lead to the formation of a massive black hole in the pair-instability mass gap (∼50−135 M⊙). Such a merger-formed black hole is expected to typically have a high spin (a ∼ 0.7). If such a massive black hole acquires another black hole it may lead to another merger detectable by LIGO/Virgo in gravitational waves. Acquiring a companion may be hindered by gravitational-wave kick/recoil, which accompanies the first merger and may quickly remove the massive black hole from its parent globular or nuclear cluster. We test whether it is possible for a massive merger-formed black hole in the pair-instability gap to be retained in its parent cluster and have low spin. Such a black hole would be indistinguishable from a primordial black hole. Methods. We employed results from numerical relativity calculations of black hole mergers to explore the range of gravitational-wave recoil velocities for various combinations of merging black hole masses and spins. We compared merger-formed massive black hole speeds with typical escape velocities from globular and nuclear clusters. Results. We show that a globular cluster is highly unlikely to form and retain a ∼100 M⊙ black hole if the spin of the black hole is low (a ≲ 0.3). Massive merger-formed black holes with low spins acquire high recoil speeds (≳ 200 km s−1) from gravitational-wave kick during formation that exceed typical escape speeds from globular clusters (∼ 50 km s−1). However, a very low-spinning (a ∼ 0.1) and massive (∼100 M⊙) black hole could be formed and retained in a galactic nuclear star cluster. Even though such massive merger-formed black holes with such low spins acquire high speeds during formation (∼ 400 km s−1), they may avoid ejection since massive nuclear clusters have high escape velocities (∼ 300−500 km s−1). A future detection of a massive black hole in the pair-instability mass gap with low spin would therefore not be proof of the existence of primordial black holes, which are sometimes claimed to have low spins and arbitrarily high masses.

scholarly journals The host galaxies of z = 7 quasars: predictions from the BlueTides simulation

2020 ◽  
Vol 499 (3) ◽  
pp. 3819-3836 ◽  
Author(s):  
Madeline A Marshall ◽  
Yueying Ni ◽  
Tiziana Di Matteo ◽  
J Stuart B Wyithe ◽  
Stephen Wilkins ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Mass Relation ◽  
Host Galaxies ◽  
Massive Black Holes ◽  
Massive Galaxies ◽  
James Webb Space Telescope ◽  
Galaxy Sample ◽  
Minor Mergers ◽  
Stellar Masses

ABSTRACT We examine the properties of the host galaxies of $z=7$ quasars using the large volume, cosmological hydrodynamical simulation BlueTides. We find that the 10 most massive black holes and the 191 quasars in the simulation (with $M_{\textrm{UV,AGN}}\lt M_{\textrm{UV,host}}$) are hosted by massive galaxies with stellar masses $\log (M_\ast /\, {\rm M}_{\odot })=10.8\pm 0.2$, and $10.2\pm 0.4$, which have large star formation rates of $513_{-351}^{+1225}\, {\rm M}_{\odot }/\rm {yr}$ and $191_{-120}^{+288}\, {\rm M}_{\odot }/\rm {yr}$, respectively. The hosts of the most massive black holes and quasars in BlueTides are generally bulge-dominated, with bulge-to-total mass ratio $B/T\simeq 0.85\pm 0.1$; however, their morphologies are not biased relative to the overall $z=7$ galaxy sample. We find that the hosts of the most massive black holes and quasars are compact, with half-mass radii $R_{0.5}=0.41_{-0.14}^{+0.18}$ kpc and $0.40_{-0.09}^{+0.11}$ kpc, respectively; galaxies with similar masses and luminosities have a wider range of sizes with a larger median value, $R_{0.5}=0.71_{-0.25}^{+0.28}$ kpc. We make mock James Webb Space Telescope (JWST) images of these quasars and their host galaxies. We find that distinguishing the host from the quasar emission will be possible but still challenging with JWST, due to the small sizes of quasar hosts. We find that quasar samples are biased tracers of the intrinsic black hole–stellar mass relation, following a relation that is 0.2 dex higher than that of the full galaxy sample. Finally, we find that the most massive black holes and quasars are more likely to be found in denser environments than the typical $M_{\textrm{BH}}\gt 10^{6.5}\, {\rm M}_{\odot }$ black hole, indicating that minor mergers play at least some role in growing black holes in the early Universe.

scholarly journals Formation of massive black holes in ultracompact dwarf galaxies: migration of primordial intermediate-mass black holes in N-body simulation

2020 ◽  
Vol 496 (1) ◽  
pp. 921-932
Author(s):  
Henriette Wirth ◽  
Kenji Bekki
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dwarf Galaxies ◽  
Model Parameters ◽  
Intermediate Mass ◽  
Massive Black Hole ◽  
Massive Black Holes ◽  
Wide Range ◽  
Central Regions ◽  
Low Mass

ABSTRACT Recent observational studies of ultracompact dwarf galaxies (UCDs) have discovered the massive black hole (MBH), with masses of more than ${10^6~\rm M_\odot }$, in their central regions. We here consider that these MBHs can be formed through the merging of intermediate-mass black hole (IMBH), with masses of (103–105) M⊙, within the stellar nuclei of dwarf galaxies, which are progenitors of UCDs. We numerically investigate this formation process for a wide range of model parameters using N-body simulations. This means that IMBH growth and feedback is neglected in this study. We find that only massive IMBHs of $10^5~\rm M_\odot$ sink into the central regions of their host dwarf ($\approx 10^{10}~\rm M_\odot$) to be gravitationally trapped by its stellar nucleus within less than 1 Gyr in most dwarf models. We also find that lighter IMBHs with $(1\!-\!30) \times 10^3~\rm M_\odot$ sink into the centre in low-mass dwarfs ($\approx 10^{9}~\rm M_\odot$) due to more efficient dynamical frictionitionally, we show that the IMBHs can form binaries in the centre and, rarely, before they reach the centre, which may lead to the IMBHs merging and thus emitting gravitational waves that could be detected by LISA. Finally, we discuss the required number of IMBHs for the MBH formation in UCDs and the physical roles of stellar nuclei in IMBH binaries and mergers.

scholarly journals X-ray properties of reverberation-mapped AGNs with super-Eddington accreting massive black holes

2019 ◽  
Vol 15 (S356) ◽  
pp. 143-143
Author(s):  
Jaya Maithil ◽  
Michael S. Brotherton ◽  
Bin Luo ◽  
Ohad Shemmer ◽  
Sarah C. Gallagher ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Accretion Rate ◽  
Time Lags ◽  
Black Hole Mass ◽  
Host Galaxies ◽  
Massive Black Holes ◽  
X Ray ◽  
Photon Index ◽  
The Impact

AbstractActive Galactic Nuclei (AGN) exhibit multi-wavelength properties that are representative of the underlying physical processes taking place in the vicinity of the accreting supermassive black hole. The black hole mass and the accretion rate are fundamental for understanding the growth of black holes, their evolution, and the impact on the host galaxies. Recent results on reverberation-mapped AGNs show that the highest accretion rate objects have systematic shorter time-lags. These super-Eddington accreting massive black holes (SEAMBHs) show BLR size 3-8 times smaller than predicted by the Radius-Luminosity (R-L) relationship. Hence, the single-epoch virial black hole mass estimates of highly accreting AGNs have an overestimation of a factor of 3-8 times. SEAMBHs likely have a slim accretion disk rather than a thin disk that is diagnostic in X-ray. I will present the extreme X-ray properties of a sample of dozen of SEAMBHs. They indeed have a steep hard X-ray photon index, Γ, and demonstrate a steeper power-law slope, ασx.

scholarly journals Gaseous Disks in the Nuclei of Elliptical Galaxies

1997 ◽  
Vol 163 ◽  
pp. 620-625 ◽  
Author(s):  
H. Ford ◽  
Z. Tsvetanov ◽  
L. Ferrarese ◽  
G. Kriss ◽  
W. Jaffe ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Angular Momentum ◽  
Accretion Disks ◽  
Large Scale ◽  
Elliptical Galaxies ◽  
Central Mass ◽  
Massive Black Holes ◽  
Radio Jets

AbstractHST images have led to the discovery that small (r ~ 1″ r ~ 100 – 200 pc), well-defined, gaseous disks are common in the nuclei of elliptical galaxies. Measurements of rotational velocities in the disks provide a means to measure the central mass and search for massive black holes in the parent galaxies. The minor axes of these disks are closely aligned with the directions of the large–scale radio jets, suggesting that it is angular momentum of the disk rather than that of the black hole that determines the direction of the radio jets. Because the disks are directly observable, we can study the disks themselves, and investigate important questions which cannot be directly addressed with observations of the smaller and unresolved central accretion disks. In this paper we summarize what has been learned to date in this rapidly unfolding new field.

scholarly journals Feeding and feedback from little monsters: AGN in dwarf galaxies

2020 ◽  
Vol 15 (S359) ◽  
pp. 238-242
Author(s):  
Mar Mezcua
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Early Universe ◽  
Dwarf Galaxies ◽  
Scaling Relations ◽  
Strong Impact ◽  
Hole Formation ◽  
Intermediate Mass ◽  
Black Hole Formation ◽  
Low Mass

AbstractDetecting the seed black holes from which quasars formed is extremely challenging; however, those seeds that did not grow into supermassive should be found as intermediate-mass black holes (IMBHs) of 100 – 105 M⊙ in local dwarf galaxies. The use of deep multiwavelength surveys has revealed that a population of actively accreting IMBHs (low-mass AGN) exists in dwarf galaxies at least out to z ˜3. The black hole occupation fraction of these galaxies suggests that the early Universe seed black holes formed from direct collapse of gas, which is reinforced by the possible flattening of the black hole-galaxy scaling relations at the low-mass end. This scenario is however challenged by the finding that AGN feedback can have a strong impact on dwarf galaxies, which implies that low-mass AGN in dwarf galaxies might not be the untouched relics of the early seed black holes. This has important implications for seed black hole formation models.

scholarly journals The Merger Rate of Black Holes in a Primordial Black Hole Cluster

Physics ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 372-378
Author(s):  
Viktor D. Stasenko ◽  
Alexander A. Kirillov
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Mass Spectrum ◽  
Star Clusters ◽  
Primordial Black Hole ◽  
Primordial Black Holes ◽  
Central Black Hole ◽  
Solar Mass ◽  
Merger Rate

In this paper, the merger rate of black holes in a cluster of primordial black holes (PBHs) is investigated. The clusters have characteristics close to those of typical globular star clusters. A cluster that has a wide mass spectrum ranging from 10−2 to 10M⊙ (Solar mass) and contains a massive central black hole of the mass M•=103M⊙ is considered. It is shown that in the process of the evolution of cluster, the merger rate changed significantly, and by now, the PBH clusters have passed the stage of active merging of the black holes inside them.

scholarly journals Massive Black Holes in Star Clusters. II. Realistic Cluster Models

2004 ◽  
Vol 613 (2) ◽  
pp. 1143-1156 ◽  
Author(s):  
Holger Baumgardt ◽  
Junichiro Makino ◽  
Toshikazu Ebisuzaki
Keyword(s):  
Black Holes ◽  
Star Clusters ◽  
Cluster Models ◽  
Massive Black Holes
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