X-Ray Observations of M32 with ASCA

M32 is the nearest dwarf elliptical galaxy. Its center is known to have a mass concentration of 3 × 106 M⊙, which is usually interpreted as an evidence of a super massive black hole. We observed M32 with ASCA two times in July and August of 1996. An X-ray source was detected at the center of M32 and its first broad-band X-ray spectra were obtained. ASCA observations of M32 limit the activity of the central black hole to be less than 10−6 times of the Eddington limit. We also found two other bright sources within 12 arcmin from the M32 center. One is the newly appeared X-ray source and the other is G144. In this paper, we summarize the results on the new source and G144. For M32, please refer to the publication (Loewenstein et al. 1997).

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ASCA Observations of Narrow-Line Seyfert 1 Galaxies

International Astronomical Union Colloquium ◽

10.1017/s0252921100039592 ◽

1997 ◽

Vol 159 ◽

pp. 40-43 ◽

Cited By ~ 2

Author(s):

K. Hayashida

Keyword(s):

Black Hole ◽

Narrow Line ◽

Black Hole Mass ◽

Central Black Hole ◽

X Ray ◽

Eddington Limit

AbstractASCA observations of four narrow-line Seyfert 1 galaxies are presented. Among the four sources, two show X-ray spectra consisting of soft and hard components. Rapid X-ray variability is observed in all four sources. We estimate the central black-hole mass of these sources and find indications that the apparent luminosities exceed the Eddington limit under some assumptions.

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Weighing the Quiescent Central Black Hole in an Elliptical Galaxy with X‐Ray‐Emitting Gas

The Astrophysical Journal ◽

10.1086/589709 ◽

2008 ◽

Vol 683 (1) ◽

pp. 161-171 ◽

Cited By ~ 42

Author(s):

Philip J. Humphrey ◽

David A. Buote ◽

Fabrizio Brighenti ◽

Karl Gebhardt ◽

William G. Mathews

Keyword(s):

Black Hole ◽

Elliptical Galaxy ◽

Central Black Hole ◽

X Ray

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

Publications of the Astronomical Society of Japan ◽

10.1093/pasj/psab009 ◽

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.

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Central Black Hole Masses in Active Galactic Nuclei Inferred from X‐Ray Variability

The Astrophysical Journal ◽

10.1086/305736 ◽

1998 ◽

Vol 500 (2) ◽

pp. 642-659 ◽

Cited By ~ 72

Author(s):

Kiyoshi Hayashida ◽

Sigenori Miyamoto ◽

Shunji Kitamoto ◽

Hitoshi Negoro ◽

Hajime Inoue

Keyword(s):

Black Hole ◽

Active Galactic Nuclei ◽

Galactic Nuclei ◽

Central Black Hole ◽

X Ray ◽

Black Hole Masses

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TWO FAMILIES OF EXACT DISKS WITH A CENTRAL BLACK HOLE

International Journal of Modern Physics D ◽

10.1142/s0218271896000060 ◽

1996 ◽

Vol 05 (01) ◽

pp. 53-63 ◽

Cited By ~ 28

Author(s):

JOSÉ P.S. LEMOS ◽

PATRICIO S. LETELIER

Keyword(s):

Black Hole ◽

Topological Defect ◽

Rotational Velocity ◽

The Other ◽

Central Black Hole ◽

Counter Rotation ◽

Infinite Extent ◽

Self Similar ◽

Physical Effects ◽

Many Particles

The gravitational field of a configuration formed by a static disk and a Schwarzschild black hole is analysed for two families of disks. The matter of the disks is made of counter-rotating particles with as many particles rotating to one side as to the other, in such a way that the net angular momentum is zero and the disk is static. The first family consists of peculiar disks, in the sense that they are generated by two opposite dipoles. The particles of the disk have no pressure or centrifugal support. However, when there is a central black hole, centrifugal balance in the form of counter-rotation appears. The second family is a one parameter family of self-similar disks which includes at one end a Newtonian disk, and at the other a topological defect of spacetime. The presence of the black hole impresses more rotational velocity to the particles. These two families are of infinite extent. Some interesting physical effects are studied.

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A Multi-Frequency Study of the Milky Way-Like Spiral Galaxy NGC 6744

Publications of the Astronomical Society of Australia ◽

10.1017/pasa.2018.9 ◽

2018 ◽

Vol 35 ◽

Cited By ~ 3

Author(s):

Miranda Yew ◽

Miroslav D. Filipović ◽

Quentin Roper ◽

Jordan D. Collier ◽

Evan J. Crawford ◽

...

Keyword(s):

Black Hole ◽

Milky Way ◽

Formation Rate ◽

Radio Continuum ◽

Starburst Galaxy ◽

Radio Sources ◽

Wide Field ◽

Central Black Hole ◽

X Ray ◽

Continuum Data

AbstractWe present a multi-frequency study of the intermediate spiral SAB(r)bc type galaxy NGC 6744, using available data from the Chandra X-Ray telescope, radio continuum data from the Australia Telescope Compact Array and Murchison Widefield Array, and Wide-field Infrared Survey Explorer infrared observations. We identify 117 X-ray sources and 280 radio sources. Of these, we find nine sources in common between the X-ray and radio catalogues, one of which is a faint central black hole with a bolometric radio luminosity similar to the Milky Way’s central black hole. We classify 5 objects as supernova remnant (SNR) candidates, 2 objects as likely SNRs, 17 as H ii regions, 1 source as an AGN; the remaining 255 radio sources are categorised as background objects and one X-ray source is classified as a foreground star. We find the star-formation rate (SFR) of NGC 6744 to be in the range 2.8–4.7 M⊙~yr − 1 signifying the galaxy is still actively forming stars. The specific SFR of NGC 6744 is greater than that of late-type spirals such as the Milky Way, but considerably less that that of a typical starburst galaxy.

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Mass transfer on a nuclear timescale in models of supergiant and ultra-luminous X-ray binaries

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935453 ◽

2019 ◽

Vol 628 ◽

pp. A19 ◽

Cited By ~ 6

Author(s):

M. Quast ◽

N. Langer ◽

T. M. Tauris

Keyword(s):

Mass Transfer ◽

Black Hole ◽

Neutron Star ◽

Roche Lobe ◽

High Mass ◽

X Rays ◽

X Ray ◽

Mass Ratios ◽

X Ray Binaries ◽

Eddington Limit

Context. The origin and number of the Galactic supergiant X-ray binaries is currently not well understood. They consist of an evolved massive star and a neutron star or black-hole companion. X-rays are thought to be generated from the accretion of wind material donated by the supergiant, while mass transfer due to Roche-lobe overflow is mostly disregarded because the high mass ratios of these systems are thought to render this process unstable. Aims. We investigate how the proximity of supergiant donor stars to the Eddington limit, and their advanced evolutionary stage, may influence the evolution of massive and ultra-luminous X-ray binaries with supergiant donor stars (SGXBs and ULXs). Methods. We constructed models of massive stars with different internal hydrogen and helium gradients (H/He gradients) and different hydrogen-rich envelope masses, and exposed them to slow mass-loss to probe the response of the stellar radius. In addition, we computed the corresponding Roche-lobe overflow mass-transfer evolution with our detailed binary stellar evolution code, approximating the compact objects as point masses. Results. We find that a H/He gradient in the layers beneath the surface, as it is likely present in the well-studied donor stars of observed SGBXs, can enable mass transfer in SGXBs on a nuclear timescale with a black-hole or a neutron star accretor, even for mass ratios in excess of 20. In our binary evolution models, the donor stars rapidly decrease their thermal equilibrium radius and can therefore cope with the inevitably strong orbital contraction imposed by the high mass ratio. We find that the orbital period derivatives of our models agree well with empirical values. We argue that the SGXB phase may be preceded by a common-envelope evolution. The envelope inflation near the Eddington limit means that this mechanism more likely occurs at high metallicity. Conclusion. Our results open a new perspective for understanding that SGBXs are numerous in our Galaxy and are almost completely absent in the Small Magellanic Cloud. Our results may also offer a way to find more ULX systems, to detect mass transfer on nuclear timescales in ULX systems even with neutron star accretors, and shed new light on the origin of the strong B-field in these neutron stars.

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A broad-band X-ray spectral study of the Seyfert 1 galaxy ESO 141–G055 with XMM–Newton and NuSTAR

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2259 ◽

2020 ◽

Vol 497 (4) ◽

pp. 4213-4221

Author(s):

Ritesh Ghosh ◽

Sibasish Laha

Keyword(s):

Black Hole ◽

Spectral Study ◽

Column Density ◽

Broad Band ◽

Accretion Disc ◽

Physical Models ◽

X Ray ◽

Reflection Model ◽

Ionization Parameter

ABSTRACT We have extensively studied the broad--band X-ray spectra of the source ESO 141–G055 using all available XMM–Newton and NuSTAR observations. We detect a prominent soft excess below $2\rm \, \, {\rm keV}$, a narrow Fe line, and a Compton hump ($\gt 10\rm \, \, {\rm keV}$). The origin of the soft excess is still debated. We used two models to describe the soft excess: the blurred reflection from the ionized accretion disc and the intrinsic thermal Comptonization model. We find that both of these models explain the soft excess equally well. We confirm that we do not detect any broad Fe line in the X-ray spectra of this source, although both the physical models prefer a maximally spinning black hole scenario (a > 0.96). This may mean that either the broad Fe line is absent or blurred beyond detection. The Eddington rate of the source is estimated to be $\lambda _{\rm \, Edd}\sim 0.31$. In the reflection model, the Compton hump has a contribution from both ionized and neutral reflection components. The neutral reflector which simultaneously describes the narrow Fe K α and the Compton hump has a column density of $N_{\rm H} \ge 7\times 10^{24} \, \rm cm^{-2}$. In addition, we detect a partially covering ionized absorption with ionization parameter $\log \xi /\rm \, erg\, cm\, s^{-1}$ = $0.1^{+0.1}_{-0.1}$ and column density $N_{\rm H} =20.6^{+1.0}_{-1.0}\times 10^{22} \, \rm cm^{-2}$ with a covering factor of $0.21^{+0.01}_{-0.01}$.

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A UV Flare at the Center of the Elliptical Galaxy NGC 4552

Symposium - International Astronomical Union ◽

10.1017/s0074180900162345 ◽

1999 ◽

Vol 194 ◽

pp. 389-393 ◽

Cited By ~ 1

Author(s):

Lucio M. Buson ◽

Francesco Bertola ◽

David Burstein ◽

Michele Cappellari ◽

Sperello di Serego Alighieri ◽

...

Keyword(s):

Black Hole ◽

Energy Distribution ◽

Emission Line ◽

Line Intensity ◽

Elliptical Galaxy ◽

Line Profiles ◽

Massive Black Hole ◽

Self Consistent ◽

Intensity Ratios

A self-consistent analysis of near-UV, HST/FOC images of the elliptical galaxy NGC 4552 is used to show that its central spike has brightened by a factor ˜ 4.5 between 1991 and 1993, and has decreased its luminosity by a factor ˜ 2.0 between 1993 and 1996. A strong UV continuum over the energy distribution of the underlying galaxy is concurrently revealed shortward of λ ˜ 3200 Å by our FOS spectra extending from the near-UV to red wavelengths. Nuclear emission-line profiles of both permitted and forbidden lines are best modelled with a combination of broad and narrow components, with FWHM of ˜ 3000 km s−1 and ˜ 700 km s−1, respectively. Current diagnostics based on the emission line intensity ratios definitely places the spike among AGNs, just at the border between Seyferts and LINERs. This evidence argues for the variable central spike being produced by a modest accretion event onto a central massive black hole (BH), with the accreted material having possibly being stripped from a star in a close fly-by with the BH. In this regard, one has to look at NGC 4552 as the faintest known AGN.

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