scholarly journals The Nuclear Reddening Curve for Active Galactic Nuclei and the Shape of the Infrared to X‐Ray Spectral Energy Distribution

2004 ◽  
Vol 616 (1) ◽  
pp. 147-156 ◽  
Author(s):  
C. Martin Gaskell ◽  
Rene W. Goosmann ◽  
Robert R. J. Antonucci ◽  
David H. Whysong
Keyword(s):  
Energy Distribution ◽  
Active Galactic Nuclei ◽  
Spectral Energy Distribution ◽  
Galactic Nuclei ◽  
Spectral Energy ◽  
X Ray

scholarly journals THE SIMULTANEOUS OPTICAL-TO-X-RAY SPECTRAL ENERGY DISTRIBUTION OF SOFT X-RAY SELECTED ACTIVE GALACTIC NUCLEI OBSERVED BY SWIFT

2010 ◽  
Vol 187 (1) ◽  
pp. 64-106 ◽  
Author(s):  
Dirk Grupe ◽  
Stefanie Komossa ◽  
Karen M. Leighly ◽  
Kim L. Page
Keyword(s):  
Energy Distribution ◽  
Active Galactic Nuclei ◽  
Spectral Energy Distribution ◽  
Galactic Nuclei ◽  
Spectral Energy ◽  
X Ray

scholarly journals To TDE or not to TDE: the luminous transient ASASSN-18jd with TDE-like and AGN-like qualities

2020 ◽  
Vol 494 (2) ◽  
pp. 2538-2560 ◽  
Author(s):  
J M M Neustadt ◽  
T W-S Holoien ◽  
C S Kochanek ◽  
K Auchettl ◽  
J S Brown ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Spectral Energy Distribution ◽  
Galactic Nuclei ◽  
Spectral Energy ◽  
Tidal Disruption ◽  
Optical Telescope ◽  
X Ray ◽  
Radiated Energy ◽  
The Galaxy ◽  
Order Of Magnitude

ABSTRACT We present the discovery of ASASSN-18jd (AT 2018bcb), a luminous optical/ultraviolet(UV)/X-ray transient located in the nucleus of the galaxy 2MASX J22434289–1659083 at z = 0.1192. Over the year after discovery, Swift UltraViolet and Optical Telescope (UVOT) photometry shows the UV spectral energy distribution of the transient to be well modelled by a slowly shrinking blackbody with temperature $T \sim 2.5 \times 10^{4} \, {\rm K}$, a maximum observed luminosity of $L_{\rm max} = 4.5^{+0.6}_{-0.3}\times 10^{44} \, {\rm erg \,s}^{-1}$, and a radiated energy of $E = 9.6^{+1.1}_{-0.6} \times 10^{51} \, {\rm erg}$. X-ray data from Swift X-Ray Telescope (XRT) and XMM–Newton show a transient, variable X-ray flux with blackbody and power-law components that fade by nearly an order of magnitude over the following year. Optical spectra show strong, roughly constant broad Balmer emission and transient features attributable to He ii, N iii–v, O iii, and coronal Fe. While ASASSN-18jd shares similarities with tidal disruption events (TDEs), it is also similar to the newly discovered nuclear transients seen in quiescent galaxies and faint active galactic nuclei (AGNs).

scholarly journals PRINCIPAL COMPONENT ANALYSIS OF THE SPECTRAL ENERGY DISTRIBUTION AND EMISSION LINE PROPERTIES OF RED 2MASS ACTIVE GALACTIC NUCLEI

2009 ◽  
Vol 692 (2) ◽  
pp. 1180-1189 ◽  
Author(s):  
Joanna Kuraszkiewicz ◽  
Belinda J. Wilkes ◽  
Gary Schmidt ◽  
Paul S. Smith ◽  
Roc Cutri ◽  
...  
Keyword(s):  
Principal Component Analysis ◽  
Energy Distribution ◽  
Emission Line ◽  
Active Galactic Nuclei ◽  
Spectral Energy Distribution ◽  
Galactic Nuclei ◽  
Principal Component ◽  
Component Analysis ◽  
Spectral Energy

ERRATUM: “THE OBSCURED FRACTION OF ACTIVE GALACTIC NUCLEI IN THE XMM-COSMOS SURVEY: A SPECTRAL ENERGY DISTRIBUTION PERSPECTIVE” (2013, ApJ, 777, 86)

2014 ◽  
Vol 784 (2) ◽  
pp. 176 ◽  
Author(s):  
E. Lusso ◽  
J. F. Hennawi ◽  
A. Comastri ◽  
G. Zamorani ◽  
G. T. Richards ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Active Galactic Nuclei ◽  
Spectral Energy Distribution ◽  
Galactic Nuclei ◽  
Spectral Energy

scholarly journals Low Radiative Efficiency Accretion at Work in Active Galactic Nuclei: The Nuclear Spectral Energy Distribution of NGC 4565

2006 ◽  
Vol 651 (2) ◽  
pp. 728-734 ◽  
Author(s):  
M. Chiaberge ◽  
R. Gilli ◽  
F. D. Macchetto ◽  
William B. Sparks
Keyword(s):  
Energy Distribution ◽  
Active Galactic Nuclei ◽  
Spectral Energy Distribution ◽  
Galactic Nuclei ◽  
Spectral Energy ◽  
Radiative Efficiency

The bumps in the spectral energy distribution of active galactic nuclei

1991 ◽  
Vol 373 ◽  
pp. 405 ◽  
Author(s):  
Marcella Contini ◽  
Sueli M. Viegas
Keyword(s):  
Energy Distribution ◽  
Active Galactic Nuclei ◽  
Spectral Energy Distribution ◽  
Galactic Nuclei ◽  
Spectral Energy

scholarly journals Photometric redshifts for X-ray-selected active galactic nuclei in the eROSITA era

2019 ◽  
Vol 489 (1) ◽  
pp. 663-680 ◽  
Author(s):  
M Brescia ◽  
M Salvato ◽  
S Cavuoti ◽  
T T Ananna ◽  
G Riccio ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Large Fraction ◽  
Spectral Energy Distribution ◽  
Galactic Nuclei ◽  
Training Sample ◽  
Spectral Energy ◽  
Ancillary Data ◽  
Photometric Redshifts ◽  
X Ray

ABSTRACT With the launch of eROSITA (extended Roentgen Survey with an Imaging Telescope Array), successfully occurred on 2019 July 13, we are facing the challenge of computing reliable photometric redshifts for 3 million of active galactic nuclei (AGNs) over the entire sky, having available only patchy and inhomogeneous ancillary data. While we have a good understanding of the photo-z quality obtainable for AGN using spectral energy distribution (SED)-fitting technique, we tested the capability of machine learning (ML), usually reliable in computing photo-z for QSO in wide and shallow areas with rich spectroscopic samples. Using MLPQNA as example of ML, we computed photo-z for the X-ray-selected sources in Stripe 82X, using the publicly available photometric and spectroscopic catalogues. Stripe 82X is at least as deep as eROSITA will be and wide enough to include also rare and bright AGNs. In addition, the availability of ancillary data mimics what can be available in the whole sky. We found that when optical, and near- and mid-infrared data are available, ML and SED fitting perform comparably well in terms of overall accuracy, realistic redshift probability density functions, and fraction of outliers, although they are not the same for the two methods. The results could further improve if the photometry available is accurate and including morphological information. Assuming that we can gather sufficient spectroscopy to build a representative training sample, with the current photometry coverage we can obtain reliable photo-z for a large fraction of sources in the Southern hemisphere well before the spectroscopic follow-up, thus timely enabling the eROSITA science return. The photo-z catalogue is released here.

scholarly journals An obscured AGN population hidden in the VIPERS galaxies: identification through spectral energy distribution decomposition

2020 ◽  
Vol 495 (2) ◽  
pp. 1853-1873
Author(s):  
E Pouliasis ◽  
G Mountrichas ◽  
I Georgantopoulos ◽  
A Ruiz ◽  
M Yang ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Spectral Energy Distribution ◽  
Broad Band ◽  
Galactic Nuclei ◽  
Spectral Energy ◽  
X Ray ◽  
Star Forming ◽  
Star Forming Regions ◽  
Redshift Survey ◽  
Selection Of

ABSTRACT The detection of X-ray emission constitutes a reliable and efficient tool for the selection of active galactic nuclei (AGNs), although it may be biased against the most heavily absorbed AGNs. Simple mid-infrared (IR) broad-band selection criteria identify a large number of luminous and absorbed AGNs, yet again host contamination could lead to non-uniform and incomplete samples. Spectral energy distribution (SED) decomposition is able to decouple the emission from the AGN versus that from star-forming regions, revealing weaker AGN components. We aim to identify the obscured AGN population in the VIMOS Public Extragalactic Redshift Survey in the Canada–France–Hawaii Telescope Legacy Survey W1 field through SED modelling. We construct SEDs for 6860 sources and identify 160 AGNs at a high confidence level using a Bayesian approach. Using optical spectroscopy, we confirm the nature of ∼85 per cent of the AGNs. Our AGN sample is highly complete (∼92 per cent) compared to mid-IR colour-selected AGNs, including a significant number of galaxy-dominated systems with lower luminosities. In addition to the lack of X-ray emission (80 per cent), the SED fitting results suggest that the majority of the sources are obscured. We use a number of diagnostic criteria in the optical, IR, and X-ray regimes to verify these results. Interestingly, only 35 per cent of the most luminous mid-IR-selected AGNs have X-ray counterparts suggesting strong absorption. Our work emphasizes the importance of using SED decomposition techniques to select a population of type II AGNs, which may remain undetected by either X-ray or IR colour surveys.

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