scholarly journals Mildly obscured active galaxies and the cosmic X-ray background

2016 ◽  
Vol 590 ◽  
pp. A49 ◽  
Author(s):  
V. Esposito ◽  
R. Walter
Keyword(s):  
Active Galaxies ◽  
X Ray ◽  
X Ray Background

Extragalactic X-ray sources and the diffuse X-ray background

1979 ◽  
Vol 366 (1726) ◽  
pp. 391-402 ◽  
Keyword(s):  
Spatial Distribution ◽  
Euclidean Space ◽  
Active Galaxies ◽  
Clusters Of Galaxies ◽  
Optical Identification ◽  
X Ray ◽  
Luminosity Functions ◽  
Sky Survey ◽  
Order Of Magnitude ◽  
X Ray Background

Results from the Ariel 5 sky survey instrument relating to the properties and the spatial distribution of extragalactic X-ray sources are discussed. The lg N -lg S relation for sources in the 2A catalogue is consistent with a uniform distribution of sources in Euclidean space. In addition, measure­ments of fluctuations in the X-ray background suggest that the Euclidean form of the source counts can be extrapolated to flux levels at least an order of magnitude fainter than the 2A catalogue limit. Information is also available from the optical identification of 2A sources which, through redshift measurements, enables the X-ray luminosity functions of the two main classes of source, namely clusters of galaxies and active galaxies, to be determined. The luminosity functions can be used to calculate the contribution of clusters of galaxies and active galaxies to the diffuse X-ray background in the 2-10 keV range. It is found that cosmological evolution of one or both populations is required to account for the diffuse X-ray background entirely in terms of the integrated emission from these sources.

scholarly journals 9.18. Galactic winds in active galaxies

1998 ◽  
Vol 184 ◽  
pp. 417-418 ◽  
Author(s):  
S. Veilleux ◽  
J. Bland-Hawthorn ◽  
G. Cecil ◽  
P. Shopbell
Keyword(s):  
Absorption Line ◽  
Galaxy Formation ◽  
Large Scale ◽  
Large Scale Structure ◽  
Active Galaxies ◽  
Large Scale Circulation ◽  
X Ray ◽  
Hubble Sequence ◽  
Galactic Winds ◽  
X Ray Background

The effects of large-scale galactic winds in active galaxies may be far-reaching. It has been suggested that the Hubble sequence can be understood in terms of a galaxy's greater ability to sustain winds with increasing bulge-to-disk ratio. The large-scale circulation of gas associated with these galactic winds might help explain the mass-metallicity relation between galaxies and the metallicity-radius relation within galaxies. Galactic winds probably contribute non-negligibly to the cosmic X-ray background and may be involved in the quasar absorption-line phenomenon. The cosmological implications of the wind phenomenon have been widely explored in the context of proto-galaxies and quasars. The extremely energetic galactic winds that were likely associated with galaxy formation almost certainly played a key role in heating and ionizing the intergalactic medium at high redshifts and may have created the seeds for the large-scale structure we see today.

X-Ray counts and contribution to the X-ray background of an IR population of starburst and active galaxies

2003 ◽  
Vol 324 (12) ◽  
pp. 170-170 ◽  
Author(s):  
M. Polletta ◽  
C.J. Lonsdale ◽  
C. Xu ◽  
B.J. Wilkes
Keyword(s):  
Active Galaxies ◽  
X Ray ◽  
X Ray Background

scholarly journals Seyfert Galaxies and the Hard X-Ray Background: ArtificialChandraObservations of [FORMULA][F]z=0.3[/F][/FORMULA] Active Galaxies

2006 ◽  
Vol 131 (1) ◽  
pp. 133-142 ◽  
Author(s):  
K. C. Peterson ◽  
S. C. Gallagher ◽  
A. E. Hornschemeier ◽  
M. P. Muno ◽  
E. C. Bullard
Keyword(s):  
Seyfert Galaxies ◽  
Active Galaxies ◽  
X Ray ◽  
X Ray Background

Very low luminosity active galaxies and the X-ray background

1984 ◽  
Vol 283 ◽  
pp. 479 ◽  
Author(s):  
M. Elvis ◽  
A. Soltan ◽  
W. C. Keel
Keyword(s):  
Active Galaxies ◽  
X Ray ◽  
X Ray Background

X-ray Astronomy and the IR Background

2001 ◽  
Vol 204 ◽  
pp. 335-345
Author(s):  
Richard Mushotzky
Keyword(s):  
Star Formation ◽  
Intergalactic Medium ◽  
Massive Stars ◽  
Active Galaxies ◽  
Infrared Galaxies ◽  
Metal Production ◽  
X Ray ◽  
Luminous Infrared Galaxies ◽  
Early Origin ◽  
X Ray Background

I review the recent Chandra results on the sources of the X-ray background and the X-ray properties of the SCUBA sources. We conclude that 10–20% of the IR background is produced by active galaxies and a similar fraction of the SCUBA sources harbor luminous AGN. Many of the Chandra sources are apparently luminous infrared galaxies themselves, but factors of 2–10 below the SCUBA limits. We summarize the X-ray evidence for metal production in groups and clusters and point out that these data require considerably more star formation than inferred from optical stellar data. The abundance ratios of Fe and Si indicate that much of the metals in groups and clusters was produced by massive stars, and the lack of evolution in Fe out to z ~ 0.5 argues for quite an early origin for the metals. This same process also seems to have injected considerable energy into the gas in groups and clusters, which may have dominated the mechanism of star formation and produced a metal-enriched intergalactic medium

scholarly journals Primeval clusters of galaxies and the X-ray background

1978 ◽  
Vol 79 ◽  
pp. 445-446
Author(s):  
Edwin M. Kellogg
Keyword(s):  
Background Radiation ◽  
Active Galaxies ◽  
Point Sources ◽  
Clusters Of Galaxies ◽  
Sky Surveys ◽  
X Ray ◽  
Large Factor ◽  
X Ray Background

The X-ray telescope for HEAO-B, due for launch next year, will extend our observing power in X-ray astronomy by a very large factor. For example, its sensitivity to point sources will be 103 greater than the limit of existing X-ray sky surveys. Even more intriguing will be its capability to image the all-sky X-ray background radiation on an arc minute or sub arc minute scale. the origin of this background is still a mystery. the simplest hypothesis, that it is the integral of radiation from the more distant members of the classes of discrete X-ray sources such as clusters of galaxies, Seyferts, QSO's and other active galaxies, can only explain part of the background.

scholarly journals Precursor active galaxies and the cosmic X-ray background

Nature ◽  
1981 ◽  
Vol 290 (5806) ◽  
pp. 483-485 ◽  
Author(s):  
Elihu Boldt ◽  
Darryl Leiter
Keyword(s):  
Active Galaxies ◽  
X Ray ◽  
X Ray Background

Clustering dependence of Chandra COSMOS Legacy AGN on host galaxy properties

2019 ◽  
Vol 15 (S356) ◽  
pp. 226-226
Author(s):  
Viola Allevato
Keyword(s):  
Dark Matter ◽  
Formation Rate ◽  
Stellar Mass ◽  
Active Galaxies ◽  
Host Galaxy ◽  
Mass Star ◽  
Mass Relation ◽  
Dark Matter Halos ◽  
X Ray

AbstractThe presence of a super massive BH in almost all galaxies in the Universe is an accepted paradigm in astronomy. How these BHs form and how they co-evolve with the host galaxy is one of the most intriguing unanswered problems in modern Cosmology and of extreme relevance to understand the issue of galaxy formation. Clustering measurements can powerfully test theoretical model predictions of BH triggering scenarios and put constraints on the typical environment where AGN live in, through the connection with their host dark matter halos. In this talk, I will present some recent results on the AGN clustering dependence on host galaxy properties, such as galaxy stellar mass, star formation rate and specific BH accretion rate, based on X-ray selected Chandra COSMOS Legacy Type 2 AGN. We found no significant AGN clustering dependence on galaxy stellar mass and specif BHAR for Type 2 COSMOS AGN at mean z ∼ 1.1, with a stellar - halo mass relation flatter than predicted for non active galaxies in the Mstar range probed by our sample. We also observed a negative clustering dependence on SFR, with AGN hosting halo mass increasing with decreasing SFR. Mock catalogs of active galaxies in hosting dark matter halos with logMh[Msun] > 12.5, matched to have the same X-ray luminosity, stellar mass and BHAR of COSMOS AGN predict the observed Mstar - Mh, BHAR - Mh and SFR-Mh relations, at z ∼ 1.

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