Obscured Active Galactic Nuclei and the X‐Ray, Optical, and Far‐Infrared Number Counts of Active Galactic Nuclei in the GOODS Fields

2004 ◽  
Vol 616 (1) ◽  
pp. 123-135 ◽  
Author(s):  
Ezequiel Treister ◽  
C. Megan Urry ◽  
Eleni Chatzichristou ◽  
Franz Bauer ◽  
David M. Alexander ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Far Infrared ◽  
X Ray ◽  
Number Counts

The Fall of Active Galactic Nuclei and the Rise of Star-forming Galaxies: A Close Look at the Chandra Deep Field X-Ray Number Counts

2004 ◽  
Vol 128 (5) ◽  
pp. 2048-2065 ◽  
Author(s):  
F. E. Bauer ◽  
D. M. Alexander ◽  
W. N. Brandt ◽  
D. P. Schneider ◽  
E. Treister ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
X Ray ◽  
Star Forming ◽  
Number Counts

scholarly journals The spectral energy distributions of active galactic nuclei

2019 ◽  
Vol 489 (3) ◽  
pp. 3351-3367 ◽  
Author(s):  
M J I Brown ◽  
K J Duncan ◽  
H Landt ◽  
M Kirk ◽  
C Ricci ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Flux Density ◽  
Galactic Nuclei ◽  
Far Infrared ◽  
Power Laws ◽  
Spectral Energy ◽  
Spectral Energy Distributions ◽  
Energy Distributions ◽  
Photometric Redshifts ◽  
X Ray

ABSTRACT We present spectral energy distributions (SEDs) of 41 active galactic nuclei, derived from multiwavelength photometry and archival spectroscopy. All of the SEDs span at least 0.09 to 30 $\mu$m, but in some instances wavelength coverage extends into the X-ray, far-infrared, and radio. For some active galactic nuclei (AGNs) we have fitted the measured far-infrared photometry with greybody models, while radio flux density measurements have been approximated by power laws or polynomials. We have been able to fill some of the gaps in the spectral coverage using interpolation or extrapolation of simple models. In addition to the 41 individual AGN SEDs, we have produced 72 Seyfert SEDs by mixing SEDs of the central regions of Seyferts with galaxy SEDs. Relative to the literature, our templates have broader wavelength coverage and/or higher spectral resolution. We have tested the utility of our SEDs by using them to generate photometric redshifts for 0 < z ≤ 6.12 AGNs in the Boötes field (selected with X-ray, IR, and optical criteria) and, relative to SEDs from the literature, they produce comparable or better photometric redshifts with reduced flux density residuals.

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.

scholarly journals X-ray bright active galactic nuclei in massive galaxy clusters – I. Number counts and spatial distribution

2012 ◽  
Vol 428 (4) ◽  
pp. 3509-3525 ◽  
Author(s):  
S. Ehlert ◽  
S. W. Allen ◽  
W. N. Brandt ◽  
Y. Q. Xue ◽  
B. Luo ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Active Galactic Nuclei ◽  
Galaxy Clusters ◽  
Galactic Nuclei ◽  
X Ray ◽  
Number Counts ◽  
Massive Galaxy

scholarly journals Properties of X-ray detected far-IR AGN in the green valley

2019 ◽  
Vol 15 (S356) ◽  
pp. 147-151
Author(s):  
Antoine Mahoro ◽  
Mirjana Pović ◽  
Petri Väisänen ◽  
Pheneas Nkundabakura ◽  
Beatrice Nyiransengiyumva ◽  
...  
Keyword(s):  
Star Formation ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Far Infrared ◽  
Mass Range ◽  
Infrared Emission ◽  
Active Galaxies ◽  
X Ray ◽  
Normal Galaxies ◽  
Using Data

AbstractIn this study, we analysed active galactic nuclei in the “green valley” by comparing active and non-active galaxies using data from the COSMOS field. We found that most of our X-ray detected active galactic nuclei with far-infrared emission have star formation rates higher than the ones of normal galaxies of the same stellar mass range.

scholarly journals THENuSTAREXTRAGALACTIC SURVEYS: THE NUMBER COUNTS OF ACTIVE GALACTIC NUCLEI AND THE RESOLVED FRACTION OF THE COSMIC X-RAY BACKGROUND

2016 ◽  
Vol 831 (2) ◽  
pp. 185 ◽  
Author(s):  
F. A. Harrison ◽  
J. Aird ◽  
F. Civano ◽  
G. Lansbury ◽  
J. R. Mullaney ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
X Ray ◽  
X Ray Background ◽  
Number Counts

scholarly journals LIFTING THE VEIL ON OBSCURED ACCRETION: ACTIVE GALACTIC NUCLEI NUMBER COUNTS AND SURVEY STRATEGIES FOR IMAGING HARD X-RAY MISSIONS

2011 ◽  
Vol 736 (1) ◽  
pp. 56 ◽  
Author(s):  
D. R. Ballantyne ◽  
A. R. Draper ◽  
K. K. Madsen ◽  
J. R. Rigby ◽  
E. Treister
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
X Ray ◽  
The Veil ◽  
Number Counts ◽  
Nuclei Number

Polarization Variability of Active Galactic Nuclei and X‐Ray Binaries

1997 ◽  
Vol 487 (1) ◽  
pp. 142-152 ◽  
Author(s):  
Gang Bao ◽  
Petr Hadrava ◽  
Paul J. Wiita ◽  
Ying Xiong
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
X Ray ◽  
X Ray Binaries

scholarly journals Gamma-Ray and Neutrino Signals from Accretion Disk Coronae of Active Galactic Nuclei

Galaxies ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 36
Author(s):  
Yoshiyuki Inoue ◽  
Dmitry Khangulyan ◽  
Akihiro Doi
Keyword(s):  
Active Galactic Nuclei ◽  
Gamma Ray ◽  
Galactic Nuclei ◽  
High Energy ◽  
Thermal Activity ◽  
X Ray ◽  
Cascade Models ◽  
Coronal Activity ◽  
Ngc 1068 ◽  
High Energy Particles

To explain the X-ray spectra of active galactic nuclei (AGN), non-thermal activity in AGN coronae such as pair cascade models has been extensively discussed in the past literature. Although X-ray and gamma-ray observations in the 1990s disfavored such pair cascade models, recent millimeter-wave observations of nearby Seyferts have established the existence of weak non-thermal coronal activity. In addition, the IceCube collaboration reported NGC 1068, a nearby Seyfert, as the hottest spot in their 10 yr survey. These pieces of evidence are enough to investigate the non-thermal perspective of AGN coronae in depth again. This article summarizes our current observational understanding of AGN coronae and describes how AGN coronae generate high-energy particles. We also provide ways to test the AGN corona model with radio, X-ray, MeV gamma ray, and high-energy neutrino observations.

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