Results 201 to 210 of about 9,238,867 (222)

Synchrotron intensity gradient revealing magnetic fields in galaxy clusters. [PDF]

Nat Commun
Hu Y, Stuardi C, Lazarian A, Brunetti G, Bonafede A, Ho KW.   +5 more
europepmc   +1 more source

Astroimmunology: the effects of spaceflight and its associated stressors on the immune system. [PDF]

Nat Rev Immunol
Winer DA, Du H, Kim J, Chang V, Burke M, Winer S, Costes SV, Frippiat JP, Sams C, Paul AM, Wu H, Ullrich O, Baatout S, Beheshti A, Mason CE, Choukér A, Crucian BE.   +16 more
europepmc   +1 more source

X-ray Evolution and Variability of Active Galactic Nuclei

openaire   +1 more source

Some of the next articles are maybe not open access.

Related searches:

Obscured active galactic nuclei: the hidden side of the X–ray Universe

Philosophical Transactions Series A, Mathematical, Physical, and Engineering Sciences, 2002
Most active galactic nuclei (AGN) are 'obscured', i.e. the nucleus is hiding behind a screen of absorbing material. The advantage of having the nucleus obscured is to make easier the observations of those emission components which originate in circumnuclear matter outside the absorbing regions, because in this case they are not outshone by the nuclear ...
Giorgio Matt
exaly   +6 more sources

X-ray observations and the properties of active galactic nuclei

AIP Conference Proceedings, 1990
X‐ray observations and the properties of Active Galactic Nuclei are re ed and the requirements for 21st century observations are discussed. To obtain the data necessary to directly study evolution, determine redshifts, study accretion disks and determine characteristic timescales of variability requires del E about 100 ev, a collecting at E about 6 kev
exaly   +2 more sources

X-rays from active galactic nuclei ? Hard component

Space Science Reviews, 1981
It is now well known that X-ray emission in active galactic nuclei (AGN) is a fairly common phenomenon (see M.J. Rees’s review in this volume). By examining the recent observational information from Ariel V, HEAO-1, and the Einstein Observatory, we have reached the conclusion (Tsuruta 1981) that the following interpretation may be used as a relevant ...
S. Tsuruta, F. Takahara, S. Ichimaru
openaire   +1 more source

The X-Ray Spectra of Active Galactic Nuclei

Physica Scripta, 1984
Recent observations of the X-ray spectra of active galactic nuclei are reviewed. After an outline of the properties of these sources deduced from observations at other wavelengths, the relevance of X-ray spectra to our understanding of the X-ray emission mechanisms and of the ultimate source of energy is discussed.
openaire   +1 more source

An Explanation for the Soft X-Ray Excess in Active Galactic Nuclei

2007
We present a large sample of type 1 active galactic nuclei (AGN) spectra taken with XMM‐ Newton, and fit them with both the conventional model (a power law and blackbody) and the relativistically blurred photoionized disc reflection model of Ross & Fabian. We find that the disc reflection model is a better fit.
Crummy, J., Fabian, A., Gallo, L., Ross, R.   +3 more
openaire   +3 more sources

The X-ray variability of active galactic nuclei

2008
Recent results relating to the X-ray variability exhibited by active galactic nuclei are reviewed. EXOSAT observations have established, contrary to earlier indications, that X-ray variability on a timescale of an hour or less is a relatively common feature of such sources.
openaire   +1 more source

X-Ray Variability in Active Galactic Nuclei

1998
X-ray variability is a distinguishing property of Active Galactic Nuclei (AGN), and the energetics and time scales of the emission dictate that the X-rays must originate very close to the central engine. In this review I discuss two basic topics from AGN variability research.
openaire   +1 more source