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The Palermo Swift-BAT hard X-ray catalogue. III. Results after 54 months of sky survey
Tagliaferri, G.; Cusumano, G.; Sbarufatti, B. +10 more
Aims: We present the Second Palermo Swift-BAT hard X-ray catalogue obtained by analysing data acquired in the first 54 months of the Swift mission.
Methods: Using our software dedicated to the analysis of data from coded mask telescopes, we analysed the BAT survey data in three energy bands (15-30 keV, 15-70 keV, 15-150 keV), obtaining a…
The intriguing nature of the high-energy gamma ray source XSS J12270-4859
Mukai, K.; Belloni, T.; de Martino, D. +7 more
Context. The nature of the hard X-ray source XSS J12270-4859 is still unclear. It was claimed to be a possible magnetic cataclysmic variable of the Intermediate Polar type from its optical spectrum and a possible 860 s X-ray periodicity in RXTE data. However, recent observations do not support the latter variability, leaving this X-ray source stil…
The Palermo Swift-BAT hard X-ray catalogue. II. Results after 39 months of sky survey
Campana, S.; Tagliaferri, G.; Cusumano, G. +12 more
Aims: We present the Palermo Swift-BAT hard X-ray catalogue obtained from the analysis of data acquired during the first 39 months of the Swift mission.
Methods: We developed a dedicated software to perform the data reduction, mosaicking, and source detection of the BAT survey data. We analyzed the BAT dataset in three energy bands (14-1…
INTEGRAL/IBIS 7-year All-Sky Hard X-Ray Survey. II. Catalog of sources
Sunyaev, R.; Krivonos, R.; Tsygankov, S. +3 more
This paper is the second in a series devoted to the hard X-ray (17-60 keV) whole sky survey performed by the INTEGRAL observatory over seven years. Here we present a catalog of detected sources that includes 521 objects, 449 of which exceed a 5σ detection threshold on the time-averaged map of the sky, and 53 were detected in various subsamples of …
X-ray variation statistics and wind clumping in Vela X-1
Klochkov, D.; Wilms, J.; Pottschmidt, K. +8 more
We investigate the structure of the wind in the neutron star X-ray binary system Vela X-1 by analyzing its flaring behavior. Vela X-1 shows constant flaring, with some flares reaching fluxes of more than 3.0 Crab between 20-60 keV for several 100 s, while the average flux is around 250 mCrab. We analyzed all archival INTEGRAL data, calculating the…
Seyfert 2 galaxies in the GeV band: jets and starburst
Walter, R.; Ricci, C.; Dorner, D. +2 more
Context. The Fermi/LAT collaboration recently reported the detection of starburt galaxies in the high energy Γ-ray domain, as well as radio-loud narrow-line Seyfert 1 objects.
Aims: Motivated by the presence of sources close to the location of composite starburst/Seyfert 2 galaxies in the first year Fermi/LAT catalogue, we aim at studying hig…
INTEGRAL hard X-ray spectra of the cosmic X-ray background and Galactic ridge emission
Walter, R.; Produit, N.; Courvoisier, T. J. -L. +4 more
Aims: We derive the spectra of the cosmic X-ray background (CXB) and of the Galactic ridge X-ray emission (GRXE) in the ~20-200 keV range from the data of the IBIS instrument aboard the INTEGRAL satellite obtained during the four dedicated Earth-occultation observations in early 2006.
Methods: We analyze the modulation of the IBIS/ISGRI …
What ignites on the neutron star of 4U 0614+091?
Smith, D. A.; in't Zand, J. J. M.; Sánchez-Fernández, C. +10 more
The low-mass X-ray binary 4U 0614+091 is a source of sporadic thermonuclear (type I) X-ray bursts. We find bursts with a wide variety of characteristics in serendipitous wide-field X-ray observations by the WATCH on EURECA, the ASM on RXTE, the WFCs on BeppoSAX, the FREGATE on HETE-2, the IBIS/ISGRI on INTEGRAL, and the BAT on Swift, as well as po…
Unveiling the nature of INTEGRAL objects through optical spectroscopy. VIII. Identification of 44 newly detected hard X-ray sources
Palazzi, E.; Minniti, D.; Masetti, N. +17 more
Hard X-ray surveys performed by the INTEGRAL satellite have discovered a conspicuous fraction (up to 30%) of unidentified objects among the detected sources. Here we continue our program of identification of these objects by (i) selecting probable optical candidates by means of positional cross-correlation of the INTEGRAL detections with soft X-ra…
Radioactive 26Al from the Scorpius-Centaurus association
Wang, W.; Diehl, R.; Jean, P. +7 more
Context. The Scorpius-Centaurus association is the most-nearby group of massive and young stars. As nuclear-fusion products are ejected by massive stars and supernovae into the surrounding interstellar medium, the search for characteristic γ-rays from radioactivity is one way to probe the history of activity of such nearby massive stars on a My ti…