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Growing Black Holes: Accretion in a Cosmological Context: Proceedings of the MPA/ESO/MPE/USM Joint Astronomy Conference Held at Garching, Germany, 21-25 June 2004

Andrea Merloni ; Sergei Nayakshin ; Rashid A. Sunyaev (eds.)

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Institución detectada Año de publicación Navegá Descargá Solicitá
No detectada 2005 SpringerLink

Información

Tipo de recurso:

libros

ISBN impreso

978-3-540-25275-7

ISBN electrónico

978-3-540-31639-8

Editor responsable

Springer Nature

País de edición

Reino Unido

Fecha de publicación

Información sobre derechos de publicación

© Springer-Verlag Berlin/Heidelberg 2005

Cobertura temática

Tabla de contenidos

Dynamical Models Linking BH Masses and DM Content

P. Buyle; H. Dejonghe; M. Baes

We investigate the relation between the dark matter distribution of galaxies and their central supermassive black holes which is suggested by the – relation. Since early-type galaxies appear to have larger black holes than late-type ones, we look for an equivalent pattern in the dark matter distribution as a function of Hubble type. To achieve our goal we use a state-of-the-art modelling code that allows a variety of geometries to be fitted to a combination of radio and optical observations of galaxies with different morphology.

Pp. 177-178

Super Massive Black Holes in Disk Galaxies: HST/STIS Observations for 3 new Objects

L. Coccato; M. Sarzi; E. Maria Corsini; A. Pizzella; F. Bertola

As demonstrated in [1], it is possible to detect from ground-based observations the presence of a circumnuclear Keplerian disk (CNKD) around a super massive black hole (SMBH) with a large mass (). Its identification is possible from the study of the position-velocity (PV) diagram as done by [2].

Pp. 179-180

X-ray Variability of the Milky Way

H.-J. Grimm; M. Gilfanov; R. Sunyaev

By constructing the power density spectrum of the Milky Way due to Galactic X-ray binaries (XRB) we investigate the prospect of disentangling the X-ray emission of galaxies due to SMBHs and X-ray binary populations for future X-ray missions.

Pp. 181-182

Growing Black Holes in Narrow-Line Seyfert 1 Galaxies

D. Grupe; S. Mathur

One of the most fundamental relations found among nearby galaxies and AGN is the M- relation between the black hole mass and the bulge stellar velocity dispersion (e.g. [11]). However, Narrow-Line Seyfert 1 galaxies (NLS1s) seem to deviate from this relation. We studied a sample of 75 soft X-ray selected AGN, 43 Broad Line Seyfert 1s and 32 NLS1s. We find that NLS1s lie below the M- relation as suggested by Mathur et al. [9]. Our result does not support theories of the M- relation in which the black hole mass is a constant fraction of the bulge mass (see also Mathur & Grupe in these proceedings). Black holes grow by accretion in well-formed bulges. As they grow they get closer to the M- relation of normal galaxies. Our results also support the hypothesis that NLS1s are AGN in a young state of their development [2,8].

Pp. 183-184

SMBH Mass Derived from ReverberationMapping and Gravitational Redshift

W. Kollatschny

We carried out a spectroscopic variability campaign of the narrow-line Seyfert 1 galaxy Mrk 110 with the 10m Hobby-Eberly Telescope at McDonald Observatory. High signal-to-noise spectra with exactly the same instrumentation were taken over a period of more than six months.

Pp. 185-188

First Simultaneous NIR/X-ray Flare Detection from SgrA*

A. Eckart; F. K. Baganoff; M. Morris; M.W. Bautz; W.N. Brandt; G.P. Garmire; R. Genzel; T. Ott; G.R. Ricker; C. Straubmeier; T. Viehmann; R. Schödel; G.C. Bower; J.E. Goldston

We summarize some of the results on the first simultaneous near-infrared/X-ray detection of the SgrA* counterpart which can be associated with the massive 3–4×10M  black hole at the center of the Milky Way. We report on observations with the NACO adaptive optics (AO) instrument at the European Southern Observatory’s Very Large Telescope and the ACIS-I instrument aboard the . Quasi-simultaneous observations have also been carried out at a wavelength of 3.4 mm using the Berkeley-Illinois-Maryland Association (BIMA) array. In the 2 - 8 keV X-domain we detected a flare with an excess luminosity of about 6×10 erg/s. Coincidently with the peak of the X-ray flare a fading flare of Sgr A* with >2 times the interim-quiescent flux was detected at the beginning of the NIR observations. The event overlapped with the fading part of the X-ray flare. The NIR/X-ray flare was also accompanied by increased mm-activity measured about 8 hours afterwards. The event implies that the NIR/X-ray flare emission was coupled without a time lag larger than 15 min and probably originated from the same ensemble of electrons.

Pp. 191-196

Sgr A West: A Parsec Scale Reservoirfor Accretion onto Sgr A*?

T. Paumard; J.-P. Maillard; M. Morris

Sgr A*, the super-massive black hole at the centre of the Milky Way, is surrounded by the H  region Sgr A West, which appears in projection like a mini-spiral with three “arms”. We have used high spectral resolution spectro-imaging data to analyse the velocity field of this ionised gas in a one-parsec wide field, and have come to the conclusion that the spiral pattern is only a projection effect. The mini-spiral is indeed composed of at least eight distinguishable clouds of material containing dust and ionised gas, and tidally stretched by the super-massive black hole. We have been able to derive an estimate of the mass of these clouds, as well as of their dynamical time-scale, through a kinematic model of the main “arm”. The origin and fate of this material will be discussed, in the perspective of accretion onto Sgr A*.

Pp. 197-202

Star Formation in the Accretion Disk of Sgr A* a Million Years Ago

S. Nayakshin

When the accretion disk mass exceeds about 1 % of the supermassive black hole (SMBH) mass, local gravitational instabilities develop and expected to lead to star formation inside the disk. Here we attempt to put constraints on the properties of a putative accretion disk that could have resulted in the formation of the two observed circum-nuclear young stellar rings in Sgr A* [3]. We find the minimum disk mass to be around 10. The observed relatively small velocity dispersion of the young stars rules out disks more massive than around 10: heavier stellar or gas disks would warp each other by orbital precession in an axisymmetric potential too strongly. Since the present day total mass of each of the two stellar rings is estimated to be , most of the gaseous disk mass should have been accreted by Sgr A* or used up in formation of young massive stars. The latter possibility appears to be more likely.

Pp. 203-208

Accretion in the Galactic Center: Via a Cool Disk?

B.F. Liu; F. Meyer; E. Meyer-Hofmeister

We study the interactions between a presumed cool disk and its hot corona in the Galactic Center. If the interactions are dominated by mass evaporation, the resultant evaporation rate is larger than the Bondi accretion rate of 10/yr, thus, the disk should have been depleted since the last star had formed. If the interactions result in hot gas steadily condensing into the disk, a very high mass flow rate is required, which is inconsistent with observations. We conclude that, for standard viscosity, there is no thin disk in the Galactic Center now. For very small viscosity, see [4] for an alternative model.

Pp. 209-210

A Disk in the Galactic Center in the Past?

E. Meyer-Hofmeister; F. Meyer; B. Liu

We raise the question whether in the past a disk could have existed in our Galactic Center which has disappeared now. Our model for the interaction of a cool disk and a hot corona above (Liu et al. 2004) allows to estimate an upper limit for the mass that might have been present in a putative accretion disk after a last star forming event, but would now have evaporated by coronal action.

Pp. 211-212