scholarly journals The X‐Ray Spectral Properties and Variability of Luminous High‐Redshift Active Galactic Nuclei

2005 ◽  
Vol 630 (2) ◽  
pp. 729-739 ◽  
Author(s):  
O. Shemmer ◽  
W. N. Brandt ◽  
C. Vignali ◽  
D. P. Schneider ◽  
X. Fan ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Spectral Properties ◽  
High Redshift ◽  
Galactic Nuclei ◽  
X Ray

scholarly journals OPTICAL SPECTRAL PROPERTIES OFSWIFTBURST ALERT TELESCOPE HARD X-RAY-SELECTED ACTIVE GALACTIC NUCLEI SOURCES

2010 ◽  
Vol 710 (1) ◽  
pp. 503-539 ◽  
Author(s):  
Lisa M. Winter ◽  
Karen T. Lewis ◽  
Michael Koss ◽  
Sylvain Veilleux ◽  
Brian Keeney ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Spectral Properties ◽  
Galactic Nuclei ◽  
X Ray

SpitzerObservations of Optically “Invisible” Radio and X‐Ray Sources: High‐Redshift Active Galactic Nuclei

2005 ◽  
Vol 626 (1) ◽  
pp. 58-69 ◽  
Author(s):  
J. L. Higdon ◽  
S. J. U. Higdon ◽  
D. W. Weedman ◽  
J. R. Houck ◽  
E. Le Floc’h ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
High Redshift ◽  
Galactic Nuclei ◽  
X Ray

scholarly journals The hard X-ray luminosity function of high-redshift (3 < z ≲ 5) active galactic nuclei

2014 ◽  
Vol 445 (4) ◽  
pp. 3557-3574 ◽  
Author(s):  
F. Vito ◽  
R. Gilli ◽  
C. Vignali ◽  
A. Comastri ◽  
M. Brusa ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Luminosity Function ◽  
High Redshift ◽  
Galactic Nuclei ◽  
X Ray

scholarly journals THE EVOLUTION AND ENVIRONMENTS OF X-RAY EMITTING ACTIVE GALACTIC NUCLEI IN HIGH-REDSHIFT LARGE-SCALE STRUCTURES

2012 ◽  
Vol 746 (2) ◽  
pp. 155 ◽  
Author(s):  
N. Rumbaugh ◽  
D. D. Kocevski ◽  
R. R. Gal ◽  
B. C. Lemaux ◽  
L. M. Lubin ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Large Scale ◽  
High Redshift ◽  
Galactic Nuclei ◽  
X Ray ◽  
Large Scale Structures ◽  
Scale Structures

scholarly journals Very High Redshift X-Ray–selected Active Galactic Nuclei in the Chandra Deep Field–North

2003 ◽  
Vol 584 (2) ◽  
pp. L61-L64 ◽  
Author(s):  
A. J. Barger ◽  
L. L. Cowie ◽  
P. Capak ◽  
D. M. Alexander ◽  
F. E. Bauer ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
High Redshift ◽  
Galactic Nuclei ◽  
X Ray ◽  
Very High

scholarly journals ROSAT Observations of Active Galactic Nuclei

1994 ◽  
Vol 159 ◽  
pp. 53-62 ◽  
Author(s):  
W. Brinkmann
Keyword(s):  
Active Galactic Nuclei ◽  
Spectral Properties ◽  
Galactic Nuclei ◽  
High Sensitivity ◽  
Good Energy Resolution ◽  
Ongoing Research ◽  
X Ray ◽  
Sky Survey ◽  
Good Energy ◽  
First Time

The large number of Active Galactive Nuclei detected for the first time through their X-ray emission in the ROSAT All Sky Survey as well as the first measurements of the X-ray emission of many previously known AGN provide a new unprecedented large basis for the statistical and morphological exploration of these objects.The soft energy range of the X-Ray Telescope, the good energy resolution of the PSPC detector, and the high sensitivity of the instrument further allows an investigation of the spectral properties of sources in this energetically important energy band.A short overview is given of the actual ongoing research concentrating on the study of the soft X-ray class properties of the various types of AGN.

scholarly journals X-ray emission of z > 2.5 active galactic nuclei can be obscured by their host galaxies

2019 ◽  
Vol 623 ◽  
pp. A172 ◽  
Author(s):  
C. Circosta ◽  
C. Vignali ◽  
R. Gilli ◽  
A. Feltre ◽  
F. Vito ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
High Redshift ◽  
Galactic Nuclei ◽  
Far Infrared ◽  
Host Galaxy ◽  
Spectral Energy ◽  
X Rays ◽  
Host Galaxies ◽  
X Ray ◽  
Stellar Masses

We present a multiwavelength study of seven active galactic nuclei (AGN) at spectroscopic redshift >2.5 in the 7 Ms Chandra Deep Field South that were selected for their good far-infrared (FIR) and submillimeter (submm) detections. Our aim is to investigate the possibility that the obscuration observed in the X-rays can be produced by the interstellar medium (ISM) of the host galaxy. Based on the 7 Ms Chandra spectra, we measured obscuring column densities NH,  X in excess of 7 × 1022 cm−2 and intrinsic X-ray luminosities LX >  1044 erg s−1 for our targets, as well as equivalent widths for the Fe Kα emission line EWrest ≳ 0.5−1 keV. We built the UV-to-FIR spectral energy distributions (SEDs) by using broadband photometry from the CANDELS and Herschel catalogs. By means of an SED decomposition technique, we derived stellar masses (M* ∼ 1011 M⊙), IR luminosities (LIR >  1012 L⊙), star formation rates (SFR ∼ 190−1680 M⊙ yr−1) and AGN bolometric luminosities (Lbol ∼ 1046 erg s−1) for our sample. We used an empirically calibrated relation between gas masses and FIR/submm luminosities and derived Mgas ∼ 0.8−5.4 × 1010 M⊙. High-resolution (0.3−0.7″) ALMA data (when available, CANDELS data otherwise) were used to estimate the galaxy size and hence the volume enclosing most of the ISM under simple geometrical assumptions. These measurements were then combined to derive the column density associated with the ISM of the host, which is on the order of NH,  ISM ∼ 1023−24 cm−2. The comparison between the ISM column densities and those measured from the X-ray spectral analysis shows that they are similar. This suggests that at least at high redshift, significant absorption on kiloparsec scales by the dense ISM in the host likely adds to or substitutes that produced by circumnuclear gas on parsec scales (i.e., the torus of unified models). The lack of unobscured AGN among our ISM-rich targets supports this scenario.

Clumpy accretion flows in active galactic nuclei: X-ray variability and spectral properties

2010 ◽  
Author(s):  
W. Ishibashi ◽  
T. J.-L. Courvoisier ◽  
A. Comastri ◽  
L. Angelini ◽  
M. Cappi
Keyword(s):  
Active Galactic Nuclei ◽  
Spectral Properties ◽  
Galactic Nuclei ◽  
X Ray ◽  
Accretion Flows

scholarly journals The OPTX Project: Comparing the Optical and X-Ray Spectral Properties of Active Galactic Nuclei

2009 ◽  
Vol 5 (S267) ◽  
pp. 142-142
Author(s):  
Laura Trouille ◽  
Amy Barger
Keyword(s):  
Active Galactic Nuclei ◽  
Spectral Properties ◽  
Classification Scheme ◽  
Galactic Nuclei ◽  
Complete Sample ◽  
X Ray ◽  
Central Engine

AbstractUsing a uniformly selected and highly spectroscopically complete sample of Chandra X-ray sources, we show that one cannot use X-ray spectral classifications and optical spectral classifications equivalently. Until a better understanding is reached for how the X-ray and optical classifications relate to the obscuration of the central engine, the use of a mixed classification scheme can only complicate the interpretation of X-ray AGN samples.

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