Search Publications
The XMM cluster outskirts project (X‑ COP )
Pointecouteau, E.; Paltani, S.; Molendi, S. +3 more
Galaxy clusters are thought to grow hierarchically through the continuous merging and accretion of smaller structures across cosmic time. In the local Universe, these phenomena are still active in the outer regions of massive clusters ($R>R_{500}$), where the matter distribution is expected to become clumpy and asymmetric because of the presenc…
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…
Merger shocks in Abell 3667 and the Cygnus A cluster
Finoguenov, A.; Wik, D. R.; Sarazin, C. L.
We present new XMM-Newton observations of the northwest (NW) radio relic region in the cluster Abell 3667. We detect a jump in the X-ray surface brightness and X-ray temperature at the sharp outer edge of the radio relic which indicate that this is the location of a merger shock with a Mach number of about 2. Comparing the radio emission to the sh…
Bulk motion measurements in clusters of galaxies with ATHENA-like missions
Nevalainen, J.
The hierarchical formation of clusters of galaxies by accretion of material releases gravitational energy which dissipates into the intracluster gas. The process heats the material and generates gas turbulence and bulk motions and thus kinetic pressure. Mapping the velocity fields of the moving subunits would enable a new diagnostics tool for clus…
X-ray measurement of the elemental abundances at the outskirts of the Perseus cluster with Suzaku
Hayashida, K.; Tsunemi, H.; Ueda, S. +1 more
We report on the abundance of metals (Mg and Fe) in the intracluster medium (ICM) at the outskirts (0.2 r200-0.8 r200) of the Perseus cluster. The X-ray spectra were obtained in the Suzaku/XIS mapping observations of this region. We employ single temperature models to fit all the X-ray spectra. The ICM temperature smoothly de…