The cosmic history of the X–ray background

2005 ◽  
Vol 363 (1828) ◽  
pp. 685-694 ◽  
Author(s):  
Amy J. Barger
Keyword(s):  
Black Hole ◽  
Galactic Nuclei ◽  
X Ray ◽  
Supermassive Black Hole ◽  
Black Hole Accretion ◽  
History Of ◽  
Dominant Period ◽  
X Ray Background ◽  
Hole Accretion ◽  
Cosmic History

The Chandra and XMM–Newton X–ray observatories have detected obscured active galactic nuclei (AGN) and almost fully resolved the X–ray background into discrete sources. Ground–based observations of the X–ray sources enable the reconstruction of the history of supermassive black hole accretion from the earliest times to the present. A dramatic cosmic downsizing of AGN luminosities is seen at recent times. Correspondingly, the production rate of the AGN radiation drops rapidly, and the dominant period of supermassive black hole production is seen to be at redshifts near z = 1.

Supermassive Black Hole Accretion History Inferred from a Large Sample of [ITAL]CHANDRA[/ITAL][ITAL]Chandra[/ITAL] Hard X-Ray Sources

2001 ◽  
Vol 122 (5) ◽  
pp. 2177-2189 ◽  
Author(s):  
A. J. Barger ◽  
L. L. Cowie ◽  
M. W. Bautz ◽  
W. N. Brandt ◽  
G. P. Garmire ◽  
...  
Keyword(s):  
Black Hole ◽  
Large Sample ◽  
X Ray ◽  
Supermassive Black Hole ◽  
Black Hole Accretion ◽  
Hole Accretion

scholarly journals The 3 Ms Chandra campaign on Sgr A*: a census of X-ray flaring activity from the Galactic center

2013 ◽  
Vol 9 (S303) ◽  
pp. 374-378
Author(s):  
J. Neilsen ◽  
M. A. Nowak ◽  
C. Gammie ◽  
J. Dexter ◽  
S. Markoff ◽  
...  
Keyword(s):  
Black Hole ◽  
Spectral Resolution ◽  
Galactic Center ◽  
Progress Report ◽  
Deep Sleep ◽  
X Ray ◽  
Supermassive Black Hole ◽  
Black Hole Accretion ◽  
Sgr A ◽  
Hole Accretion

AbstractOver the last decade, X-ray observations of Sgr A* have revealed a black hole in a deep sleep, punctuated roughly once per day by brief flares. The extreme X-ray faintness of this supermassive black hole has been a long-standing puzzle in black hole accretion. To study the accretion processes in the Galactic center, Chandra (in concert with numerous ground- and space-based observatories) undertook a 3 Ms campaign on Sgr A* in 2012. With its excellent observing cadence, sensitivity, and spectral resolution, this Chandra X-ray Visionary Project (XVP) provides an unprecedented opportunity to study the behavior of the closest supermassive black hole. We present a progress report from our ongoing study of X-ray flares, including the brightest flare ever seen from Sgr A*. Focusing on the statistics of the flares and the quiescent emission, we discuss the physical implications of X-ray variability in the Galactic center.

scholarly journals Probing black hole accretion tracks, scaling relations, and radiative efficiencies from stacked X-ray active galactic nuclei

2019 ◽  
Vol 493 (1) ◽  
pp. 1500-1511 ◽  
Author(s):  
Francesco Shankar ◽  
David H Weinberg ◽  
Christopher Marsden ◽  
Philip J Grylls ◽  
Mariangela Bernardi ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Selection Bias ◽  
Stellar Mass ◽  
Supermassive Black Holes ◽  
Independent Evidence ◽  
X Ray ◽  
Black Hole Accretion ◽  
Black Hole Masses ◽  
Hole Accretion

ABSTRACT The masses of supermassive black holes at the centres of local galaxies appear to be tightly correlated with the mass and velocity dispersions of their galactic hosts. However, the local Mbh–Mstar relation inferred from dynamically measured inactive black holes is up to an order-of-magnitude higher than some estimates from active black holes, and recent work suggests that this discrepancy arises from selection bias on the sample of dynamical black hole mass measurements. In this work, we combine X-ray measurements of the mean black hole accretion luminosity as a function of stellar mass and redshift with empirical models of galaxy stellar mass growth, integrating over time to predict the evolving Mbh–Mstar relation. The implied relation is nearly independent of redshift, indicating that stellar and black hole masses grow, on average, at similar rates. Matching the de-biased local Mbh–Mstar relation requires a mean radiative efficiency ε ≳ 0.15, in line with theoretical expectations for accretion on to spinning black holes. However, matching the ‘raw’ observed relation for inactive black holes requires ε ∼ 0.02, far below theoretical expectations. This result provides independent evidence for selection bias in dynamically estimated black hole masses, a conclusion that is robust to uncertainties in bolometric corrections, obscured active black hole fractions, and kinetic accretion efficiency. For our fiducial assumptions, they favour moderate-to-rapid spins of typical supermassive black holes, to achieve ε ∼ 0.12–0.20. Our approach has similarities to the classic Soltan analysis, but by using galaxy-based data instead of integrated quantities we are able to focus on regimes where observational uncertainties are minimized.

scholarly journals BINARY ACTIVE GALACTIC NUCLEI IN STRIPE 82: CONSTRAINTS ON SYNCHRONIZED BLACK HOLE ACCRETION IN MAJOR MERGERS

2015 ◽  
Vol 815 (1) ◽  
pp. L6 ◽  
Author(s):  
Hai Fu ◽  
J. M. Wrobel ◽  
A. D. Myers ◽  
S. G. Djorgovski ◽  
Lin Yan
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Black Hole Accretion ◽  
Hole Accretion
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