Browsing Articles by Author "Wilkins, D. R."

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1H 0707−495 in 2011: an X-ray source within a gravitational radius of the event horizon

Gallo, Luigi C.; Fabian, A. C.; Zoghbi, A.; Wilkins, D. R.; Dwelly, T.; Uttley, P.; Schartel, N.; Miniutti, G.; Grupe, D.; Komossa, S. (Oxford University Press, 2012)

The narrow-line Seyfert 1 Galaxy 1H 0707−495 went into a low state from 2010 December to 2011 February, discovered by a monitoring campaign using the X-Ray Telescope on the Swift satellite. We triggered a 100 ks XMM–Newton ...
The ASTRO-H (Hitomi) x-ray astronomy satellite

Takahashi, Tadayuki; Kokubun, Motohide; Mitsuda, Kazuhisa; Kelley, Richard; Ohashi, Takaya; Aharonian, Felix; Akamatsu, Hiroki; Akimoto, Fumie; Allen, Steve; Anabuki, Naohisa; Gallo, Luigi C.; Wilkins, D. R. (SPIE International Society for Optical Engineering, 2016)

The Hitomi (ASTRO-H) mission is the sixth Japanese X-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy ...
The ASTRO-H X-ray astronomy satellite

Takahashi, Tadayuki; Mitsuda, Kazuhisa; Kelley, Richard; Aharonian, Felix; Akamatsu, Hiroki; Akimoto, Fumie; Allen, Steve; Anabuki, Naohisa; Angelini, Lorella; Arnaud, Keith; Gallo, Luigi C.; Wilkins, D. R. (Society of Photo Optical Instrumental Engineers, 2014-12-03)

The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions developed by the Institute of Space and Astronautical Science (ISAS), with a planned launch in 2015. The ASTRO-H mission is ...
Caught in the act: measuring the changes in the corona that cause the extreme variability of 1H 0707−495

Wilkins, D. R.; Kara, E.; Fabian, A. C.; Gallo, Luigi C. (Oxford University Press, 2014-09-21)

The X-ray spectra of the narrow-line Seyfert 1 galaxy, 1H 0707–495, obtained with XMM–Newton, from time periods of varying X-ray luminosity are analysed in the context of understanding the changes to the X-ray ...
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 ...
Modelling the broad Fe K alpha reverberation in the AGN NGC 4151

Cackett, E. M.; Zoghbi, A.; Reynolds, C.; Fabian, A. C.; Kara, E.; Uttley, P.; Wilkins, D. R. (Oxford University Press, 2014-01-13)

The recent detection of X-ray reverberation lags, especially in the Fe Kα line region, around active galactic nuclei (AGN) has opened up the possibility of studying the time-resolved response (reflection) of hard ...
Modelling the extreme X-ray spectrum of IRAS 13224-3809

Chiang, Chia-Ying; Walton, D. J.; Fabian, A. C.; Wilkins, D. R.; Gallo, Luigi C. (Oxford University Press, 2015-01)

The extreme narrow-line Seyfert 1 galaxy IRAS 13224-3809 shows significant variability, frequency depended time lags, and strong Fe K line and Fe L features in the long 2011 XMM-Newton observation. In this work we study ...
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 NuSTAR spectrum of Mrk 335: extreme relativistic effects within two gravitational radii of the event horizon

Parker, M. L.; Wilkins, D. R.; Fabian, A. C.; Grupe, D.; Dauser, T.; Matt, G.; Harrison, F. A.; Brenneman, L.; Boggs, S. E.; Christensen, F. E.; Gallo, Luigi C. (Oxford University Press, 2014-09-11)

We present 3–50 keV NuSTAR observations of the active galactic nuclei Mrk 335 in a very low flux state. The spectrum is dominated by very strong features at the energies of the iron line at 5–7 keV and Compton ...
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 ...
Revealing structure and evolution within the corona of the Seyfert galaxy I Zw 1

Wilkins, D. R.; Gallo, Luigi C.; Silva, C. V.; Costantini, E.; Brandt, W. N.; Kriss, G. A. (Oxford University Press, 2017-11)

X-ray spectral timing analysis is presented of XMM–Newton observations of the narrow-line Seyfert 1 galaxy I Zwicky 1 taken in 2015 January. After exploring the effect of background flaring on timing analyses, X-ray ...
Suzaku observations of Mrk 335: confronting partial covering and relativistic reflection

Gallo, Luigi C.; Wilkins, D. R.; Bonson, K.; Chiang, C.-Y.; Grupe, D.; Parker, M. L.; Zoghbi, A.; Fabian, A. C.; Komossa, S.; Longinotti, A. L. (Oxford University Press, 2015-01)

We report on the deepest X-ray observation of the narrow-line Seyfert 1 galaxy Mrk 335 in the low-flux state obtained with Suzaku. The data are compared to a 2006 high-flux Suzaku observation when the source was ∼10 times ...
Towards modelling X-ray reverberation in AGN: piecing together the extended corona

Wilkins, D. R.; Cackett, E. M.; Fabian, A. C.; Reynolds, C. S. (Oxford University Press, 2016-05-01)

Models of X-ray reverberation from extended coronae are developed from general relativistic ray tracing simulations. Reverberation lags between correlated variability in the directly observed continuum emission and that ...

Browsing Articles by Author "Wilkins, D. R."

Browsing Articles by Author "Wilkins, D. R."

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