Search Publications
Ultrafast outflows in radio-loud active galactic nuclei
Cappi, M.; Guainazzi, M.; Tombesi, F. +5 more
Recent X-ray observations show absorbing winds with velocities up to mildly relativistic values of the order of ∼0.1c in a limited sample of six broad-line radio galaxies. They are observed as blueshifted Fe XXV-XXVI K-shell absorption lines, similarly to the ultrafast outflows (UFOs) reported in Seyferts and quasars. In this work we extend the se…
Azimuthally resolved X-ray spectroscopy to the edge of the Perseus Cluster
Simionescu, A.; Fabian, A. C.; Allen, S. W. +9 more
We present the results from extensive, new observations of the Perseus Cluster of galaxies, obtained as a Suzaku Key Project. The 85 pointings analysed span eight azimuthal directions out to 2° = 2.6 Mpc, to and beyond the virial radius r200 ∼ 1.8 Mpc, offering the most detailed X-ray measurements of the intracluster medium (ICM) at lar…
Iron Kα emission in type-I and type-II active galactic nuclei
Paltani, S.; Gandhi, P.; Ricci, C. +3 more
The narrow Fe Kα line is one of the main signatures of the reprocessing of X-ray radiation from the material surrounding supermassive black holes, and it has been found to be omnipresent in the X-ray spectra of active galactic nuclei (AGN). In this work, we study the characteristics of the narrow Fe Kα line in different types of AGN. Using the res…
Multiple density discontinuities in the merging galaxy cluster CIZA J2242.8+5301
Simionescu, A.; Croston, J. H.; Brüggen, M. +4 more
CIZA J2242.8+5301, a merging galaxy cluster at z = 0.19, hosts a double-relic system and a faint radio halo. Radio observations at frequencies ranging from a few MHz to several GHz have shown that the radio spectral index at the outer edge of the northern relic corresponds to a shock of Mach number 4.6_{-0.9}^{+1.3}, under the assumptions of diffu…
The quiescent X-ray spectrum of accreting black holes
Reis, Rubens C.; Miller, Jon M.; Cackett, Edward M. +2 more
The quiescent state is the dominant accretion mode for black holes on all mass scales. Our knowledge of the X-ray spectrum is limited due to the characteristic low luminosity in this state. Herein, we present an analysis of the sample of dynamically confirmed stellar-mass black holes observed in quiescence in the Chandra/XMM-Newton/Suzaku era resu…
Search for X-ray occultations in active galactic nuclei
Salvati, M.; Risaliti, G.; Pietrini, P. +1 more
Recent time-resolved spectral studies of a few active galactic nuclei (AGNs) in hard X-rays revealed occultations of the X-ray primary source probably by broad-line region (BLR) clouds. An important open question on the structure of the circumnuclear medium of AGN is whether this phenomenon is common, i.e. whether a significant fraction of the X-r…
Variations in the pulsation and spectral characteristics of OAO 1657-415
Maitra, Chandreyee; Paul, Biswajit; Pradhan, Pragati +2 more
We present broad-band pulsation and spectral characteristics of the accreting X-ray pulsar OAO 1657-415 with a 2.2 d long Suzaku observation carried out covering its orbital phase range ∼0.4-0.6, with respect to the mid-eclipse. During the last third of the observation, the X-ray count rate in both the X-ray Imaging Spectrometer (XIS) and the HXD-…
Fe Kα line in hard X-ray emitting symbiotic stars
Eze, R. N. C.
The 6.4 keV iron emission line is typically created by irradiation of the neutral (or low ionized) iron by a hard X-ray source. Whereas the 6.7 and 7.0 keV emission lines are mainly produced by photoionization and collisional excitation in hot plasma, the 6.4 keV fluorescence line is typically a signature of either reflection from an accretion dis…
Iron-line and continuum variations in the XMM-Newton and Suzaku spectra of the neutron-star low-mass X-ray binary 4U 1636-53
Homan, Jeroen; Hiemstra, Beike; Belloni, Tomaso +3 more
We used six simultaneous XMM-Newton and Rossi X-ray Timing Explorer plus five Suzaku observations to study the continuum spectrum and the iron emission line in the neutron-star low-mass X-ray binary 4U 1636-53. We modelled the spectra with two thermal components (representing the accretion disc and boundary layer), a Comptonized component (represe…
X-ray observations of VY Scl-type nova-like binaries in the high and low state
Mukai, K.; Orio, M.; Shugarov, S. +1 more
Four VY Scl-type nova-like systems were observed in X-rays during both the low- and the high-optical states. We examined Chandra, ROSAT, Swift and Suzaku archival observations of BZ Cam, MV Lyr, TT Ari and V794 Aql. The X-ray flux of BZ Cam is higher during the low state, but there is no supersoft X-ray source (SSS) as hypothesized in previous art…