scholarly journals An effective selection method for low-mass active black holes and first spectroscopic identification

2016 ◽  
Vol 68 (3) ◽  
pp. 40 ◽  
Author(s):  
Tomoki Morokuma ◽  
Nozomu Tominaga ◽  
Masaomi Tanaka ◽  
Naoki Yasuda ◽  
Hisanori Furusawa ◽  
...  
Keyword(s):  
Black Holes ◽  
Selection Method ◽  
Effective Selection ◽  
Low Mass ◽  
Spectroscopic Identification

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 formation of high-mass black holes in low-mass X-ray binaries

New Astronomy ◽  
1999 ◽  
Vol 4 (4) ◽  
pp. 313-323 ◽  
Author(s):  
G.E. Brown ◽  
C.-H. Lee ◽  
Hans A. Bethe
Keyword(s):  
Black Holes ◽  
High Mass ◽  
X Ray ◽  
Low Mass ◽  
X Ray Binaries

scholarly journals Finding Local Low-mass Supermassive Black Holes

2008 ◽  
Author(s):  
Smita Mathur ◽  
Himel Ghosh ◽  
Laura Ferrarese ◽  
Fabrizio Fiore ◽  
Sandip K. Chakrabarti ◽  
...  
Keyword(s):  
Black Holes ◽  
Supermassive Black Holes ◽  
Low Mass

AGN and the necessity of feedback

2005 ◽  
Vol 363 (1828) ◽  
pp. 695-704 ◽  
Author(s):  
Andrew J. Benson
Keyword(s):  
Black Holes ◽  
Star Formation ◽  
Galaxy Formation ◽  
Supermassive Black Holes ◽  
Observational Evidence ◽  
Theoretical Studies ◽  
Feedback Process ◽  
Low Mass

There is now good observational evidence that some type of feedback process must operate within galaxies. Such a process has long been thought to exist on the basis of theoretical studies of galaxy formation. This feedback is responsible for regulating the rate of star formation and thereby preventing the formation of an overabundance of low–mass galaxies. There is gathering evidence that this feedback process must somehow involve the supermassive black holes thought to dwell in the centres of galaxies.

scholarly journals Launching proton-dominated jets from accreting Kerr Black Holes: the case of M87

2011 ◽  
Vol 1 (1) ◽  
pp. 4 ◽  
Author(s):  
Felix F. Brezinski ◽  
Ahmad A. Hujeirat
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Black Holes ◽  
Angular Momentum ◽  
Event Horizon ◽  
Accretion Disk ◽  
Lorentz Factor ◽  
Spin Parameter ◽  
Low Mass ◽  
Kerr Black Holes

A general relativistic model for the formation and acceleration of low mass-loaded jets from systems containing accreting black holes is presented. The model is based on previous numerical results and theoretical studies in the Newtonian regime, but modified to include the effects of space-time curvature in the vicinity of the event horizon of a spinning black hole. It is argued that the boundary layer between the Keplerian accretion disk and the event horizon is best suited for the formation and acceleration of the accretion-powered jets in active galactic nuclei and micro-quasars. The model presented here is based on matching the solutions of three different regions: i- a weakly magnetized Keplerian accretion disk in the outer part, where the transport of angular momentum is mediated through the magentorotational instability, ii- a strongly magnetized, advection-dominated and turbulent-free boundary layer (BL) between the outer cold accretion disk and the event horizon and where the plasma rotates sub-Keplerian and iii- a transition zone (TZ) between the BL and the overlying corona, where the electrons and protons are thermally uncoupled, highly dissipative and rotate super-Keplerian. In the BL, the gravitation-driven dynamical collapse of the plasma increases the strength of the poloidal magnetic field (PMF) significantly, subsequently suppressing the generation and dissipation of turbulence and turning off the primary source of heating. In this case, the BL appears much fainter than standard disk models so as if the disk truncates at a certain radius. The action of the PMF in the BL is to initiate torsional Alf`ven waves that transport angular momentum from the embedded plasma vertically into the TZ, where a significant fraction of the shear-generated toroidal magnetic field reconnects, thereby heating the protons up to the virial-temperature. Also, the strong PMF forces the electrons to cool rapidly, giving rise therefore to the formation of a gravitationally unbound two-temperature proton-dominated outflow. Our model predicts the known correlation between the Lorentz-factor and the spin parameter of the BH. It also shows that the effective surface of the BL, through which the baryons flow into the TZ, shrinks with increasing the spin parameter, implying therefore that low mass-loaded jets most likely originate from around Kerr black holes. When applying our model to the jet in the elliptical galaxy M87, we find a spin parameter <em>a ∈</em> [0.99, 0.998], a transition radius rtr ≈ 30 gravitational radii and a fraction of 0.05 − 0.1 of the mass accretion rate goes into the TZ, where the plasma speeds up its outward-oriented motion to reach a Lorentz factor Γ <em>∈</em> [2.5, 5.0] at rtr.

The demographics of central massive black holes in low-mass early-type galaxies

2019 ◽  
Vol 14 (S353) ◽  
pp. 286-288
Author(s):  
Dieu D. Nguyen
Keyword(s):  
Black Holes ◽  
Adaptive Optics ◽  
Mass Range ◽  
Early Type ◽  
Host Galaxies ◽  
Seed Formation ◽  
Unique Constraint ◽  
Low Mass ◽  
Important Extension ◽  
Stellar Masses

AbstractThe existence intermediate mass black holes (IMBH, MBH ≲ 106M⊙) at the centers low-mass galaxies with stellar masses between (1–10)×10M⊙ are key to constraining the origin of black hole (BH) seeds and understanding the physics deriving the co-evolution of central BHs and their host galaxies. However, finding and weighing IMBH is challenging. Here, we present the first observational evidence for such IMBHs at the centers of the five nearest early-type galaxies (D < 3.5 Mpc, ETGs) revealed by adaptive optics kinematics from Gemini and VLT and high-resolution HST spectroscopy. We find that all five galaxies appear to host IMBHs with four of the five having masses below 1 million M⊙ and the lowest mass BH being only ∼7,000 M⊙. This work provides a first glimpse of the demographics of IMBHs in this galaxy mass range and at velocity dispersions < 70 km/s, and thus provides an important extension to the bulge mass and galaxy dispersion scaling relations. The ubiquity of central BHs in these galaxies provides a unique constraint on BH seed formation scenarios, favoring a formation mechanism that produces an abundance of low-mass seed BHs.

scholarly journals Searching for Low-Mass Supermassive Black Holes

1999 ◽  
Vol 194 ◽  
pp. 422-423
Author(s):  
Michele Cappellari ◽  
Francesco Bertola ◽  
Enrico M. Corsini ◽  
José G. Funes ◽  
Alessandro Pizzella ◽  
...  
Keyword(s):  
Black Holes ◽  
Supermassive Black Holes ◽  
Low Mass

It has become generally accepted that most or possibly all ellipticals and bulges of spirals harbor supermassive black holes in their center (see Ho 1998 for a recent review).

scholarly journals X-Ray Heated Accretion Discs Around Stellar Mass Black Holes

2004 ◽  
Vol 194 ◽  
pp. 200-201
Author(s):  
Ivan Hubeny ◽  
Dayal T. Wickramasinghe
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Vertical Structure ◽  
Black Body ◽  
Incident Radiation ◽  
Accretion Discs ◽  
Distribution Models ◽  
Solar Mass ◽  
X Ray ◽  
Low Mass

We investigate the effects of irradiation on the vertical structure of accretion discs around black holes and its impact on the emergent energy distribution. Models are presented for a 10 Solar mass black hole in a low mass X-ray binary assuming a black body spectrum for the incident radiation. We show that for a disc annulus at a given radius, the spectra become increasingly distorted as the incident flux increases relative to the viscously generated heating flux in the disc. Significant effects are apparent for rings even at distances of ~ 10,000 Schwarzschild radii from the black hole for realistic dilution factors.

scholarly journals Non-Linear Resonances in Accretion Disks and QPOs

2004 ◽  
Vol 194 ◽  
pp. 128-129
Author(s):  
Włodek Kluźniak
Keyword(s):  
Black Holes ◽  
Neutron Stars ◽  
Accretion Disk ◽  
Accretion Disks ◽  
High Frequency ◽  
Light Curves ◽  
X Ray ◽  
Non Linear ◽  
Low Mass ◽  
X Ray Binaries

AbstractNon-linear oscillations in the accretion disk are favored as an explanation of high-frequency QPOs observed in the light curves of low-mass X-ray binaries containing neutron stars, black holes, or white dwarfs.

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