Search Publications
4U 1626-67 as seen by Suzaku before and after the 2008 torque reversal
Pottschmidt, K.; Wilson-Hodge, C. A.; Camero-Arranz, A. +3 more
Aims: The accretion-powered pulsar 4U 1626-67 experienced a new torque reversal at the beginning of 2008, after about 18 years of steadily spinning down. The main goal of the present work is to study this recent torque reversal that occurred in February 2008.
Methods: We present a spectral analysis of this source using two pointed observ…
The X-ray variability history of Markarian 3
Guainazzi, M.; Miniutti, G.; La Parola, V. +2 more
Context. The unified scenario for active galactic nuclei (AGN) postulates that our orientation with respect to a parsec-scale azimuthally-symmetric gas and dust system causes the difference in their phenomenology in the optical/UV and X-ray bands. Only recently have high-resolution radio (VLBI) and IR interferometric observations provided direct c…
The Suzaku X-ray spectrum of NGC 3147. Further insights on the best "true" Seyfert 2 galaxy candidate
Bianchi, S.; Guainazzi, M.; Barcons, X. +2 more
Context. NGC 3147 is so far the most convincing case of a "true" Seyfert 2 galaxy, i.e. a source genuinely lacking the broad line regions.
Aims: We obtained a Suzaku observation with the double aim to study in more detail the iron line complex, and to check the Compton-thick hypothesis for the lack of observed optical broad lines.
Method…
VLT and Suzaku observations of the Fermi pulsar PSR J1028-5819
Marelli, M.; Razzano, M.; Esposito, P. +4 more
Context. The launch of the Fermi Gamma-ray Space Telescope in 2008 opened new perspectives in the multi-wavelength studies of neutron stars, with more than 100 γ-ray pulsars having since been detected. While most Fermi pulsars had previously been observed in the X-rays with Chandra and XMM-Newton, optical observations with 8 m-class telescopes exi…
Staring at 4U 1909+07 with Suzaku
Wilms, J.; Pottschmidt, K.; Fürst, F. +4 more
We present an analysis of the neutron star high mass X-ray binary (HMXB) 4U 1909+07 mainly based on Suzaku data. We extend the pulse period evolution, which behaves in a random-walk like manner, indicative of direct wind accretion. Studying the spectral properties of 4U 1909+07 between 0.5 to 90 keV we find that a power-law with an exponential cut…
The magnetar candidate AX J1818.8-1559
Tiengo, A.; Götz, D.; Mereghetti, S. +3 more
In October 2007, a hard X-ray burst was detected by the INTEGRAL satellite from a direction consistent with the position of AX J1818.8-1559, an X-ray source at low Galactic latitude discovered with the Advanced Satellite for Cosmology and Astrophysics (ASCA) satellite in 1996-1999. The short duration (0.8 s) and soft spectrum (power-law photon ind…
The nature of the multi-wavelength emission of 3C 111
Beckmann, V.; Mattana, F.; de Jong, S.
Aims: We attempt to determine the nature of the high energy emission of the radio galaxy 3C 111, by distinguishing between the effects of the thermal and non-thermal processes.
Methods: We study the X-ray spectrum of 3C 111 between 0.4 keV and 200 keV, and its spectral energy distribution, using data from the Suzaku satellite combined wi…
Active galaxy 4U 1344-60: did the relativistic line disappear?
Bianchi, S.; Guainazzi, M.; Piconcelli, E. +4 more
Context. X-ray bright active galactic nuclei represent a unique astrophysical laboratory for studying accretion physics around super-massive black holes.
Aims: 4U 1344-60 is a bright Seyfert galaxy which revealed relativistic reflection features in the archival XMM-Newton observation.
Methods: We present the spectroscopic results of new …