Browsing Articles by Subject "Active galaxies"

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A blurred reflection interpretation for the intermediate flux state in Mrk 335

Gallo, Luigi C.; Bonson, K.; Fabian, A. C.; Grupe, D.; Komossa, S.; Longinotti, A. L.; Miniutti, G.; Walton, D. J.; Zoghbi, A.; Mathur, S. (Oxford University Press, 2013-01)

As part of a long-term monitoring campaign of Mrk 335, deep XMM–Newton observations catch the narrow-line Seyfert 1 galaxy (NLS1) in a complex, intermediate flux interval as the active galaxy is transiting from low to high ...
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 ...
Formation of cavities in the X-ray emitting cluster gas of Cygnus A

Clarke, David A.; Harris, D. E.; Carilli, C. L. (Royal Astronomical Society and Oxford University Press, 1997)

The ROSAT data from the cluster gas of Cygnus A are re-examined in light of a three-dimensional hydrodynamic simulation of a supersonic jet propagating in an isothermal King atmosphere designed to follow the observed density ...
The hard X-ray perspective on the soft X-ray excess

Vasudevan, Ranjan V.; Mushotzky, Richard F.; Reynolds, Christopher S.; Fabian, Andrew C.; Lohfink, Anne M.; Zoghbi, Abderahmen; Gallo, Luigi C.; Walton, Dominic (IOP Publishing Limited, 2014-04-10)

The X-ray spectra of many active galactic nuclei exhibit a “soft excess” below 1 keV, whose physical origin remains unclear. Diverse models have been suggested to account for it, including ionized reflection ...
How the effects of resonant absorption on black hole reflection spectra can mimic high-velocity outflows

Gallo, Luigi C.; Fabian, A. C. (Oxford University Press on behalf of the Royal Astronomical Society, 2011-11)

Narrow absorption lines seen in the 2–10 keV spectra of active galaxies and Galactic black holes are normally attributed to iron in high-velocity outflows or inflows. We consider the possibility that such features could ...
Insights on the X-ray weak quasar phenomenon from XMM–Newton monitoring of PHL1092

Gallo, Luigi C.; Miniutti, G.; Brandt, W. N.; Schneider, D. P.; Fabian, A. C.; Boller, Th. (Royal Astronomical SocietyOxford University Press, 2012)

PHL 1092 is a z ∼ 0.4 high-luminosity counterpart of the class of Narrow-Line Seyfert 1 galaxies. In 2008, PHL 1092 was found to be in a remarkably low X-ray flux state during an XMM–Newton observation. Its 2 keV flux ...
Is HE 0436–4717 anemic? A deep look at a bare Seyfert 1 galaxy

Bonson, K.; Gallo, Luigi C.; Vasudevan, R. (Oxford University Press, 2015-06-11)

A multi-epoch, multi-instrument analysis of the Seyfert 1 galaxy HE 0436–4717 is conducted using optical to X-ray data from XMM–Newton and Swift (including the Burst Alert Telescope). Fitting of the UV-to-X-ray spectral ...
A low-flux state in IRAS 00521−7054 seen with NuSTAR and XMM–Newton: relativistic reflection and an ultrafast outflow

Walton, Dominic; Nardini, Emanuele; Gallo, Luigi C.; Reynolds, M. T.; Ricci, C.; Dauser, Thomas; Fabian, Andrew C.; Garcia, J. A.; Harrison, F. A.; Risaliti, G.; Stern, D. (Oxford University PressRoyal Astronomical Society, 2019-01-16)

We present results from a deep, coordinated XMM–Newton + NuSTAR observation of the Seyfert 2 galaxy IRAS 00521−7054. The NuSTAR data provide the first detection of this source in ...
Multi-epoch X-ray observations of the Seyfert 1.2 galaxy Mrk 79: bulk motion of the illuminating X-ray source

Gallo, Luigi C.; Miniutti, G.; Miller, J. M.; Brenneman, L. W.; Fabian, A. C.; Guainazzi, M.; Reynolds, C. S. (Oxford University Press, 2011-02)

Multi-epoch X-ray spectroscopy (0.3–25 keV) of the Seyfert 1.2 galaxy Mrk 79 (UGC3973) spanning nearly 8 yr and a factor of 3 in broad-band flux are analysed. The data are obtained at seven epochs with either XMM–Newton ...
Nuclear spallation in active galaxies

Gallo, Luigi C.; Randhawa, J. S.; Waddell, S. G. H.; Hani, M. H.; Garcia, J. A.; Reynolds, C.S. (Oxford University Press, 2019-01-25)

A number of works point to the presence of narrow emission features at unusual energies in the X-ray spectra of active galactic nuclei or to potentially low iron abundances as possible evidence for the spallation of iron. ...
PHL 1092 as a transient extreme X-ray weak quasar

Gallo, Luigi C.; Miniutti, G.; Fabian, A. C.; Brandt, W. N.; Boller, Th. (Royal Astronomical SocietyOxford University Press, 2009)

We report a dramatic variability event in the X-ray history of the narrow-line quasar PHL 1092 (z = 0.396). Our latest 2008 XMM-Newton observation reveals a flux drop of ∼200 with respect to the previous observation performed ...
A remarkable long-term light curve and deep, low-state spectroscopy: Swift and XMM-Newton monitoring of the NLS1 galaxy Mkn 335

Gallo, Luigi C.; Gruberbauer, Michael; Grupe, Dirk; Komossa, S.; Longinotti, Anna Lia; Fabian, Andrew C.; Pradhan, Anil K.; Xu, Dawei (American Astronomical Society, 2012-04)

The narrow-line Seyfert 1 galaxy (NLS1) Mkn 335 is remarkable because it has repeatedly shown deep, long X-ray low states that show pronounced spectral structure. It has become one of the prototype active galactic nuclei ...
The rise of an ionized wind in the narrow-line Seyfert 1 galaxy Mrk 335 observed by XMM-Newton and HST

Gallo, Luigi C.; Longinotti, A. L.; Krongold, Y.; Kriss, G. A.; Ely, J.; Grupe, D.; Komossa, S.; Mathur, S.; Pradhan, A. (American Astronomical SocietyIOP Publishing, 2013-04-01)

We present the discovery of an outflowing ionized wind in the Seyfert 1 galaxy Mrk 335. Despite having been extensively observed by most of the largest X-ray observatories in the last decade, this bright source was not ...
Searching for correlations in simultaneous X-ray and UV emission in the narrow-line Seyfert 1 galaxy 1H 0707–495

Robertson, D. R. S.; Gallo, Luigi C.; Zoghbi, A.; Fabian, A. C. (Oxford University Press, 2015-09-09)

We examine simultaneous X-ray and UV light curves from multi-epoch 8 d XMM–Newton observations of the narrow line Seyfert 1 galaxy 1H 0707–495. The simultaneous observations reveal that both X-ray and UV emission are ...
Studying X-ray reprocessing and continuum variability in quasars: PG 1211+143

Gallo, Luigi C.; Bachev, R.; Grupe, D.; Boeva, S.; Ovcharov, E.; Valcheva, A.; Semkov, E.; Georgiev, Ts. (Oxford University Press, 2009-10)

We present the results from a monitoring campaign of the Narrow-Line Seyfert 1 galaxy PG 1211+143. The object was monitored with ground-based facilities (UBVRI photometry; from 2007 February to July) and with Swift [X-ray ...
The Suzaku broadband X-ray spectrum of the dwarf Seyfert galaxy NGC 4395

Gallo, Luigi C.; Iwasawa, K.; Tanaka, Y. (EDP Sciences, 2010-05)

We present a Suzaku observation of the dwarf Seyfert galaxy NGC 4395 with an estimated black hole mass of ~105M[subscript circled dot]. Rapid and strong X-ray variability with an rms amplitude of ~60 per cent is observed ...
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 ...
XMM-Newton observations of the narrow-line Seyfert 1 galaxy Mrk 335 in a historical low X-ray flux state

Gallo, Luigi C.; Grupe, Dirk; Komossa, Stefanie; Fabian, Andrew C.; Larsson, Josefin; Pradhan, Anil K.; Xu, Dawei; Miniutti, Giovanni (American Astronomical Society, 2008-07)

We report the discovery of strong soft X-ray emission lines and a hard continuum above 2 keV in the narrow-line Seyfert 1 galaxy Mrk 335 during an extremely low X-ray flux state. Mrk 335 was observed for 22 ks by XMM-Newton ...

Browsing Articles by Subject "Active galaxies"

Browsing Articles by Subject "Active galaxies"

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