2012A&A...544A..87M


C.D.S. - SIMBAD4 rel 1.7 - 2020.12.03CET19:15:22

2012A&A...544A..87M - Astronomy and Astrophysics, volume 544A, 87-87 (2012/8-1)

Coronae above accretion disks around black holes: the effect of Compton cooling.

MEYER-HOFMEISTER E., LIU B.F. and MEYER F.

Abstract (from CDS):

The geometry of the accretion flow around stellar mass and supermassive black holes depends on the accretion rate. Broad iron emission lines originating from the irradiation of cool matter can indicate that there is an inner disk below a hot coronal flow. These emission lines have been detected in X-ray binaries. Observations with the Chandra X-ray Observatory, XMM Newton, and Suzaku have confirmed the presence of these emission lines also in a large fraction of Seyfert-1 active galactic nuclei (AGN). We investigate the accretion flow geometry for which broad iron emission lines can arise in hard and soft spectral states. We study an ADAF-type coronal flow, where the ions are viscously heated and electrons receive their heat only by collisions from the ions and are Compton cooled by photons from an underlying cool disk. For a strong mass flow in the disk and the resulting strong Compton cooling only a very weak coronal flow is possible. This limitation allows the formation of ADAF-type coronae above weak inner disks in the hard state, but almost rules them out in the soft state. The observed hard X-ray luminosity in the soft state, of up to 10% or more of the total flux, indicates that there is a heating process that directly accelerates the electrons. This might point to the action of magnetic flares of disk magnetic fields reaching into the corona. Such flares have also been proposed by observations of the spectra of X-ray black hole binaries without a thermal cut-off around 200keV.

Abstract Copyright:

Journal keyword(s): accretion, accretion disks - X-rays: galaxies - black hole physics - galaxies: active - magnetic fields - galaxies: Seyfert

Simbad objects: 13

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Number of rows : 13

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 NGC 4151 Sy1 12 10 32.5771747733 +39 24 21.057727323   12.18 11.48     ~ 3413 2
2 ESO 383-35 Sy1 13 35 53.7686909139 -34 17 44.139127597   13.89 13.61 8.9   ~ 1389 0
3 V* IL Lup HXB 15 47 08.2766679321 -47 40 10.284971214           ~ 418 1
4 V* V381 Nor HXB 15 50 58.6520652623 -56 28 35.309070422   17.95 16.6     K3III 1041 0
5 [GHJ2008] 3 HXB 16 50 00.980 -49 57 43.60           K4V 353 0
6 V* V1033 Sco HXB 16 54 00.137 -39 50 44.90   15.20 14.2 16.14   F5IV 1728 1
7 V* HZ Her LXB 16 57 49.8110797681 +35 20 32.487435684 11.90 14.89 13.63 13.88   B3/6ep 1933 0
8 V* V821 Ara HXB 17 02 49.3810714542 -48 47 23.163091737 16.20 16.30 15.5     ~ 1792 0
9 NAME XTE J17464-3213 LXB 17 46 15.59637 -32 14 00.8600           ~ 616 0
10 XTE J1752-223 LXB 17 52 15.090 -22 20 32.36           ~ 162 0
11 V* V406 Vul HXB 18 58 41.580 +22 39 29.40 15.00 15.65 15.31     G5V-K0V 324 0
12 Granat 1915+105 LXB 19 15 11.54938 +10 56 44.7585           ~ 2322 0
13 HD 226868 HXB 19 58 21.6758193269 +35 12 05.782512305 9.38 9.72 8.91 8.42   O9.7Iabpvar 3958 0

    Equat.    Gal    SGal    Ecl

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2020.12.03-19:15:22

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