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X-Ray Observations of Active Galactic Nuclei [PDF]

Symposium - International Astronomical Union, 1983
HEAO 1 A2 and Einstein SSS spectral observations of Seyfert galaxies and BL Lac objects suggest that in both cases, the X-ray emission is due to relativistic particles. The five BL Lac objects have very soft spectra and at higher energies (above 10 keV) may have hard tails.
C. Megan Urry, Richard F. Mushotzky, Allyn F. Tennant, Elihu A. Boldt, Stephen S. Holt   +4 more
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X-Ray Variability of Active Galactic Nuclei [PDF]

Highlights of Astronomy, 1983
X-ray variability of active galactic nuclei is commonplace on scales from days to years. It also occurs, although rarely, on time scales as short as 200 seconds. Both these statements must be strongly qualified by the irregularity and insensitivity of the available observations. In the X-rays we expect that we are seeing deep within the active nucleus,
Daniel A. Schwartz, Greg Madejski, William H.-M. Ku   +2 more
openaire   +1 more source

Testing Physical Scenarios for the Reflection Features of Type-1 AGNs using XMM-Newton and NuSTAR Simultaneous Observations

The Astrophysical Journal, 2023
Above ∼3 keV, the X-ray spectrum of active galactic nuclei (AGNs) is characterized by the intrinsic continuum and Compton reflection features. For type-1 AGNs, several regions may contribute to the reflection.
César Ivan Victoria-Ceballos, Omaira González-Martín, Josefa Masegosa, Anna Lia Longinotti, Donaji Esparza-Arredondo, Natalia Osorio-Clavijo   +5 more
doaj   +1 more source

Unwrapping the X‐ray spectra of active galactic nuclei [PDF]

Astronomische Nachrichten, 2016
AbstractActive galactic nuclei (AGN) are complex phenomena. At the heart of an AGN is a relativistic accretion disk around a spinning supermassive black hole (SMBH) with an X‐ray emitting corona and, sometimes, a relativistic jet. On larger scales, the outer accretion disk and molecular torus act as the reservoirs of gas for the continuing AGN activity.
openaire   +3 more sources

X-RAY LUMINOSITY FUNCTIONS OF ACTIVE GALACTIC NUCLEI [PDF]

Multiwavelength AGN Surveys, 2004
To appear in the proceedings of the conference "Multiwavelenth AGN Surveys", held in Cozumel, Mexico, December 2003 (invited talk).
openaire   +2 more sources

Sources of X-rays from galaxies [PDF]

, 2011
Galactic X-ray emission is a manifestation of various high-energy phenomena and processes. The brightest X-ray sources are typically accretion-powered objects: active galactic nuclei and low- or high-mass X-ray binaries.
Liu, Persic, Porquet, Q. Daniel Wang, Revnivtsev, Revnivtsev, Sazonov, Tüllmann, Weźgowiec, Yuan, Zhang   +10 more
core   +1 more source

AMUSE-Antlia. I. Nuclear X-Ray Properties of Early-type Galaxies in a Dynamically Young Galaxy Cluster

The Astrophysical Journal, 2023
To understand the formation and growth of supermassive black holes (SMBHs) and their coevolution with host galaxies, it is essential to know the impact of environment on the activity of active galactic nuclei (AGNs).
Zhensong Hu, Yuanyuan Su, Zhiyuan Li, Kelley M. Hess, Ralph P. Kraft, William R. Forman, Paul E. J. Nulsen, Sarrvesh S. Sridhar, Andra Stroe, Junhyun Baek, Aeree Chung, Dirk Grupe, Hao Chen, Jimmy A. Irwin, Christine Jones, Scott W. Randall, Elke Roediger   +16 more
doaj   +1 more source

X-ray power law spectra in active galactic nuclei [PDF]

, 2010
X-ray spectra of active galactic nuclei (AGN) are usually described as power law spectra, characterized by the spectral slope $\alpha$ or photon index $\Gamma$. Here we discuss the X-ray spectral properties within the framework of clumpy accretion flows,
Courvoisier, Deluit, Ishibashi, Ishibashi, Kelly, Laor, McHardy, McLure, Middleton, Nandra, Niko▯ajuk, Page, Papadakis, Papadakis, Piconcelli, Porquet, Reeves, Risaliti, Shemmer, Shemmer, Soldi, T. J.-L. Courvoisier, Titarchuk, Titarchuk, W. Ishibashi, Zdziarski, Zdziarski, Zdziarski   +27 more
core   +1 more source

A Reemerging Bright Soft X-Ray State of the Changing-look Active Galactic Nucleus 1ES 1927+654: A Multiwavelength View

The Astrophysical Journal, 2023
1ES1927+654 is a nearby active galactic nucleus (AGN) that has shown an enigmatic outburst in optical/UV followed by X-rays, exhibiting strange variability patterns at timescales of months to years.
Ritesh Ghosh, Sibasish Laha, Eileen Meyer, Agniva Roychowdhury, Xiaolong Yang, J. A. Acosta–Pulido, Suvendu Rakshit, Shivangi Pandey, Josefa Becerra González, Ehud Behar, Luigi C. Gallo, Francesca Panessa, Stefano Bianchi, Fabio La Franca, Nicolas Scepi, Mitchell C. Begelman, Anna Lia Longinotti, Elisabeta Lusso, Samantha Oates, Matt Nicholl, S. Bradley Cenko, Brendan O’Connor, Erica Hammerstein, Jincen Jose, Krisztina Éva Gabányi, Federica Ricci, Sabyasachi Chattopadhyay   +26 more
doaj   +1 more source

X-Rays from Active Galactic Nuclei [PDF]

Highlights of Astronomy, 1983
Recent X-ray observations of active galactic nuclei and Seyfert galaxies in particular are briefly reviewed. The application of the efficiency limit to rapidly varying luminous sources such as NGC 6814 is discussed. It is argued that the variability and probable MeV spectral turnover imply that most of the electrons which radiate the observed flux are ...
openaire   +1 more source