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Browsing by Subject "X-ray sources, Galactic -- Accretion"

Now showing items 1-8 of 8

The Comptonization of accretion disc X-ray emission: consequences for X-ray reflection and the geometry of AGN coronae

Wilkins, D. R.; Gallo, Luigi C. (Oxford University Press, 2015-03-21)

We consider the Comptonization of the photons that make up the relativistically blurred reflection that is commonly detected from the accretion discs of active galactic nuclei by the coronae of energetic particles believed ...
Driving extreme variability: the evolving corona and evidence for jet launching in Markarian 335

Wilkins, D. R.; Gallo, Luigi C. (Oxford University Press, 2015-05-01)

Variations in the X-ray emission from the narrow-line Seyfert 1 galaxy, Markarian 335, are studied on both long and short time-scales through observations made between 2006 and 2013 with XMM–Newton, Suzaku and NuSTAR. ...
Flaring from the supermassive black hole in Mrk 335 studied with Swift and NuSTAR

Wilkins, D. R.; Gallo, Luigi C.; Grupe, D.; Bonson, K.; Komossa, S.; Fabian, A. C. (Oxford University Press, 2015-12-21)

Monitoring of the narrowline Seyfert 1 galaxy Markarian 335 (Mrk 335) with the Swift satellite discovered an X-ray flare beginning 2014 August 29. At the peak, the 0.5–5 keV count rate had increased from that in the low-flux ...
Long XMM observation of the narrow-line Seyfert 1 galaxy IRAS 13224−3809: rapid variability, high spin and a soft lag

Gallo, Luigi C.; Fabian, A. C.; Kara, E.; Walton, D. J.; Wilkins, D. R.; Ross, R. R.; Lozanov, K.; Uttley, P.; Zoghbi, A.; Miniutti, G. (Oxford University Press, 2013-03-11)

The narrow-line Seyfert 1 galaxy IRAS 13224−3809 has been observed with XMM–Newton for 500 ks. The source is rapidly variable on time-scales down to a few 100 s. The spectrum shows strong broad Fe − K and L emission ...
New constraints on the black hole low/hard state inner accretion flow with NuSTAR

Miller, J. M.; Tomsick, J. A.; Bachetti, M.; Wilkins, D. R.; Boggs, S. E.; Christensen, F. E.; Craig, W. W.; Fabian, A. C.; Grefenstette, B. W.; Hailey, C. J. (American Astronomical Society, 2015-01-20)

We report on an observation of the Galactic black hole candidate GRS 1739−278 during its 2014 outburst, obtained with NuSTAR. The source was captured at the peak of a rising “low/hard” state, at a ﬂux of ~0.3 Crab. A broad, ...
The origin of blueshifted absorption features in the X-ray spectrum of PG 1211+143: outflow or disc

Gallo, Luigi C.; Fabian, A. C. (Oxford University Press, 2013-09)

In some radio-quiet active galactic nuclei (AGN), high-energy absorption features in the X-ray spectra have been interpreted as ultrafast outflows (UFOs) – highly ionized material (e.g. Fe XXV and Fe XXVI) ejected at mildly ...
Probing the geometry and motion of AGN coronae through accretion disc emissivity profiles

Gonzalez, A. G.; Wilkins, D. R.; Gallo, Luigi C. (Oxford University Press, 2017-12)

To gain a better understanding of the inner disc region that comprises active galactic nuclei, it is necessary to understand the pattern in which the disc is illuminated (the emissivity profile) by X-rays emitted from the ...
X-ray spectral and variability properties of low-mass active galactic nuclei

Ludlam, R. M.; Cackett, E. M.; Gultekin, K.; Fabian, A. C.; Gallo, Luigi C.; Miniutti, G. (Oxford University Press, 2015-03)

We study the X-ray properties of a sample of 14 optically selected low-mass active galactic nuclei (AGN) whose masses lie within the range 10[superscript 5]–2 × 10[superscript 6] M[subscript circled dot] with XMM–Newton. ...