Search Publications
Accretion disk winds in active galactic nuclei: X-ray observations, models, and feedback
Tombesi, F.
Powerful winds driven by active galactic nuclei (AGN) are often invoked to play a fundamental role in the evolution of both supermassive black holes (SMBHs) and their host galaxies, quenching star formation and explaining the tight SMBH-galaxy relations. A strong support of this ``quasar mode'' feedback came from the recent X-ray observation of a …
The peculiar megamaser AGN NGC 1194: Comparison with the warped disk candidates NGC 1068 and NGC 4258
Vasylenko, A.; Fedorova , E.; Hnatyk, B. I. +1 more
We analyze the X-ray properties of the Compton-thick Seyfert 1.9 radio quiet AGN in NGC 1194 using INTEGRAL (ISGRI), XMM-Newton (EPIC), Swift (BAT and XRT), and Suzaku (XIS) observations. There is a set of Fe-K lines in the NGC 1194 spectrum with complex relativistic profiles that can be considered as a sign of either a warped Bardeen-Petterson ac…
Broadband short term X-ray variability of the quasar PDS 456
Tombesi, F.; Reeves, J. N.; Braito, V. +4 more
We present a detailed analysis of a recent 500 ks net exposure Suzaku observation, carried out in 2013, of the nearby (z=0.184) luminous (L_bol∼1047 erg s-1) quasar PDS 456 in which the X-ray flux was unusually low. The short term X-ray spectral variability has been interpreted in terms of variable absorption and/or intrinsic…
A new characterization of the Compton process in the ULX spectra
Makishima, K.; Kobayashi, S.; Nakazawa, K.
Attempts were made to construct a unified description of the spectra of ULX (Ultra Luminous X-ray source) objects, including their power-law (PL) state and disk-like state. Among spectral models proposed to explain either state, the present work adopts the one which combines multi-color disk (MCD) emission and its thermal Comptonization (THC). Thi…
Broadband X-ray study of the galactic black hole binary 4U 1630-47 with Suzaku
Done, C.; Hori, T.; Shidatsu, M. +4 more
We present the results from our Suzaku observations of the Galactic black hole binary 4U 1630-47. 4U 1630-47 was observed in the very high state (VHS) during the 2012 September-October outburst. The inner disk appears slightly truncated by comparison with a previous high/soft state (HSS) of this source, even by taking into account energetic coupli…
Variability of the X-ray broad iron spectral features in active galactic nuclei and black-hole binaries
Tsujimoto, M.; Ebisawa, K.; Inoue, H. +1 more
The ``broad iron spectral features'' are often seen in X-ray spectra of active galactic nuclei (AGN) and black-hole binaries (BHB). These features may be explained either by the ``relativistic disc reflection'' scenario or the ``partial covering'' scenario: It is hardly possible to determine which model is valid from time-averaged spectral analysi…