scholarly journals 9.13. Story of the discovery of a massive black hole in NGC4258

1998 ◽  
Vol 184 ◽  
pp. 407-408
Author(s):  
M. Miyoshi
Keyword(s):  
Black Hole ◽  
High Velocity ◽  
Band System ◽  
Wide Band ◽  
Massive Black Hole

In the Autumn of 1991, Nakai et al.(1993) began monitoring observations of water mega masers including NGC4258 using Nobeyama 45 m telescope. The 45 m telescope was equipped with wide band cooled HEMT receiver (22 GHz) and wide band spectrometers (AOS). Nakai used 8 AOSs which covered 4480 km/sec in velocity. It was from the wide-band system that the high velocity maser components were detected unexpectedly which locate ±1000 km/sec from the known features of the NGC4258 (Claussen et al. 1984). The finding was in May 1992 when busy Nakai got time checking the data deeply, half year had passed since the beginning of the observations.

scholarly journals H2O maser emission from the Seyfert 2 galaxy IC 2560: evidence for a super-massive black hole and a probe for mass-accretion rate

2002 ◽  
Vol 206 ◽  
pp. 400-403
Author(s):  
Yuko Ishihara ◽  
Naomasa Nakai ◽  
Naoko Iyomoto ◽  
Kazuo Makishima ◽  
Phil Diamond ◽  
...  
Keyword(s):  
Black Hole ◽  
High Velocity ◽  
Accretion Rate ◽  
Rotating Disk ◽  
Massive Black Hole ◽  
Central Mass ◽  
Maser Emission ◽  
Mass Accretion Rate ◽  
Systemic Velocity ◽  
Velocity Drift

Our observations of H2O masers have detected some high-velocity features and a secular velocity drift of the systemic features in the Seyfert 2 Galaxy IC 2560. The high-velocity features were blue- and red-shifted from the systemic velocity of 220-420 km s−1 and 210-350 km s−1, respectively. The velocity of the systemic features drifted at a secular rate of 2.62 km s−1 yr−1. Assuming the existence of a compact rotating disk as in NGC 4258, IC 2560 possesses a nuclear disk with inner and outer radii of 0.07 pc and 0.26 pc, respectively, and a confined mass of 2.8 × 106M⊙ at the center, making the central density > 2.1 × 109M⊙ pc−3. Such a dense object cannot be a cluster of stars, and this strongly suggests that the central mass is a super-massive black hole. Since the 2-10 keV luminosity of IC 2560 is 1 × 1041 erg s−1, the mass accretion rate of the suggested black hole must be 2 × 10−5M⊙ yr−1.

scholarly journals The methods for searching hypervelocity star candidates from the SDSS

2013 ◽  
Vol 9 (S298) ◽  
pp. 421-421
Author(s):  
Yinbi Li ◽  
Ali Luo ◽  
Gang Zhao ◽  
Youjun Lu
Keyword(s):  
Black Hole ◽  
Velocity Distribution ◽  
Radial Velocity ◽  
Binary Stars ◽  
High Velocity ◽  
Main Sequence ◽  
Galactic Center ◽  
Main Sequence Stars ◽  
Massive Black Hole ◽  
Stellar Spectra

AbstractHyper-velocity stars are believed to be ejected out from the Galactic center through dynamical interactions of (binary) stars with the central massive black hole(s). In this paper, we firstly select F and G type main sequence stars from about 370,000 stellar spectra of DR7. Then, we select 369 high velocity stars from main sequence samples using the radial velocity distribution. Finally, we find 13 possible unbound hyper-velocity star candidates from the 369 high velocity stars.

Axisymmetric, Three-Integral Models of Galaxies: A Massive Black Hole in NGC 3379

2000 ◽  
Vol 119 (3) ◽  
pp. 1157-1171 ◽  
Author(s):  
Karl Gebhardt ◽  
Douglas Richstone ◽  
John Kormendy ◽  
Tod R. Lauer ◽  
Edward A. Ajhar ◽  
...  
Keyword(s):  
Black Hole ◽  
Massive Black Hole

scholarly journals MONITORING STELLAR ORBITS AROUND THE MASSIVE BLACK HOLE IN THE GALACTIC CENTER

2009 ◽  
Vol 692 (2) ◽  
pp. 1075-1109 ◽  
Author(s):  
S. Gillessen ◽  
F. Eisenhauer ◽  
S. Trippe ◽  
T. Alexander ◽  
R. Genzel ◽  
...  
Keyword(s):  
Black Hole ◽  
Galactic Center ◽  
Massive Black Hole ◽  
Stellar Orbits

scholarly journals Wandering of the central black hole in a galactic nucleus and correlation of the black hole mass with the bulge mass

2021 ◽  
Author(s):  
Hajime Inoue
Keyword(s):  
Black Hole ◽  
Loss Rate ◽  
Energy Gain ◽  
Stellar Disk ◽  
Black Hole Mass ◽  
Central Black Hole ◽  
Massive Black Hole ◽  
Stellar Cluster ◽  
Upper Limit ◽  
Simple Parameter

Abstract We investigate a mechanism for a super-massive black hole at the center of a galaxy to wander in the nucleus region. A situation is supposed in which the central black hole tends to move by the gravitational attractions from the nearby molecular clouds in a nuclear bulge but is braked via the dynamical frictions from the ambient stars there. We estimate the approximate kinetic energy of the black hole in an equilibrium between the energy gain rate through the gravitational attractions and the energy loss rate through the dynamical frictions in a nuclear bulge composed of a nuclear stellar disk and a nuclear stellar cluster as observed from our Galaxy. The wandering distance of the black hole in the gravitational potential of the nuclear bulge is evaluated to get as large as several 10 pc, when the black hole mass is relatively small. The distance, however, shrinks as the black hole mass increases, and the equilibrium solution between the energy gain and loss disappears when the black hole mass exceeds an upper limit. As a result, we can expect the following scenario for the evolution of the black hole mass: When the black hole mass is smaller than the upper limit, mass accretion of the interstellar matter in the circumnuclear region, causing the AGN activities, makes the black hole mass larger. However, when the mass gets to the upper limit, the black hole loses the balancing force against the dynamical friction and starts spiraling downward to the gravity center. From simple parameter scaling, the upper mass limit of the black hole is found to be proportional to the bulge mass, and this could explain the observed correlation of the black hole mass with the bulge mass.

Effects of supernovae feedback and black hole outflows in the evolution of Dwarf Spheroidal Galaxies

2020 ◽  
Vol 15 (S359) ◽  
pp. 280-282
Author(s):  
Gustavo Amaral Lanfranchi ◽  
Anderson Caproni ◽  
Jennifer F. Soares ◽  
Larissa S. de Oliveira
Keyword(s):  
Black Hole ◽  
Homogeneous Medium ◽  
Massive Black Hole ◽  
Dwarf Spheroidal Galaxies ◽  
Stellar Feedback ◽  
Gas Removal ◽  
The Galaxy ◽  
Main Driver ◽  
Ia Supernovae ◽  
Jet Structure

AbstractThe gas evolution of a typical Dwarf Spheroidal Galaxy is investigated by means of 3D hydrodynamic simulations, taking into account the feedback of type II and Ia supernovae, the outflow of an Intermediate Massive Black Hole (IMBH) and a static cored dark matter potential. When the IMBH’s outflow is simulated in an homogeneous medium a jet structure is created and a small fraction of the gas is pushed away from the galaxy. No jet structure can be seen, however, when the medium is disturbed by supernovae, but gas is still pushed away. In this case, the main driver of the gas removal are the supernovae. The interplay between the stellar feedback and the IMBH’s outflow should be taken into account.

scholarly journals Circum-nuclear molecular disks: Role in AGN fueling and feedback

2019 ◽  
Vol 15 (S359) ◽  
pp. 312-317
Author(s):  
Francoise Combes
Keyword(s):  
Black Hole ◽  
Angular Momentum ◽  
High Resolution ◽  
Large Scale ◽  
Active Galaxy ◽  
Small Scale ◽  
Massive Black Hole ◽  
Molecular Outflows ◽  
Molecular Outflow

AbstractGas fueling AGN (Active Galaxy Nuclei) is now traceable at high-resolution with ALMA (Atacama Large Millimeter Array) and NOEMA (NOrthern Extended Millimeter Array). Dynamical mechanisms are essential to exchange angular momentum and drive the gas to the super-massive black hole. While at 100pc scale, the gas is sometimes stalled in nuclear rings, recent observations reaching 10pc scale (50mas), may bring smoking gun evidence of fueling, within a randomly oriented nuclear gas disk. AGN feedback is also observed, in the form of narrow and collimated molecular outflows, which point towards the radio mode, or entrainment by a radio jet. Precession has been observed in a molecular outflow, indicating the precession of the radio jet. One of the best candidates for precession is the Bardeen-Petterson effect at small scale, which exerts a torque on the accreting material, and produces an extended disk warp. The misalignment between the inner and large-scale disk, enhances the coupling of the AGN feedback, since the jet sweeps a large part of the molecular disk.

scholarly journals The TianQin project: Current progress on science and technology

2020 ◽  
Author(s):  
Jianwei Mei ◽  
Yan-Zheng Bai ◽  
Jiahui Bao ◽  
Enrico Barausse ◽  
Lin Cai ◽  
...  
Keyword(s):  
Black Hole ◽  
Ecliptic Plane ◽  
Mass Ratio ◽  
Massive Black Hole ◽  
Black Hole Binaries ◽  
Compact Binaries ◽  
Single Body ◽  
Science Operations ◽  
New Generation ◽  
Research Facilities

Abstract TianQin is a planned space-based gravitational wave (GW) observatory consisting of three Earth-orbiting satellites with an orbital radius of about $10^5 \, {\rm km}$. The satellites will form an equilateral triangle constellation the plane of which is nearly perpendicular to the ecliptic plane. TianQin aims to detect GWs between $10^{-4} \, {\rm Hz}$ and $1 \, {\rm Hz}$ that can be generated by a wide variety of important astrophysical and cosmological sources, including the inspiral of Galactic ultra-compact binaries, the inspiral of stellar-mass black hole binaries, extreme mass ratio inspirals, the merger of massive black hole binaries, and possibly the energetic processes in the very early universe and exotic sources such as cosmic strings. In order to start science operations around 2035, a roadmap called the 0123 plan is being used to bring the key technologies of TianQin to maturity, supported by the construction of a series of research facilities on the ground. Two major projects of the 0123 plan are being carried out. In this process, the team has created a new-generation $17 \, {\rm cm}$ single-body hollow corner-cube retro-reflector which was launched with the QueQiao satellite on 21 May 2018; a new laser-ranging station equipped with a $1.2 \, {\rm m}$ telescope has been constructed and the station has successfully ranged to all five retro-reflectors on the Moon; and the TianQin-1 experimental satellite was launched on 20 December 2019—the first-round result shows that the satellite has exceeded all of its mission requirements.

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