The Second IBIS/ISGRI Soft Gamma‐Ray Survey Catalog

Abstract

In this paper we report the second soft gamma-ray source catalog obtained with the IBIS/ ISGRI gamma-ray imager on board the INTEGRAL satellite. The scientific data set is based on more than 10 Ms of high-quality observations performed during the first 2 years of Core Program and public IBIS/ISGRI observations, and covers $50% of the whole sky. The main aim of the first survey was to scan systematically, for the first time at energies above 20 keV, the whole Galactic plane to achieve a limiting sensitivity of $1 mcrab in the central radian. The target of the second year of the INTEGRAL mission lifetime was to expand as much as possible our knowledge of the soft gamma-ray sky, with the same limiting sensitivity, to at least 50% of the whole sky, mainly by including a substantial coverage of extragalactic fields. This catalog comprises more than 200 high-energy sources detected in the energy range 20-100 keV, including new transients not active during the first year of operation, faint persistent objects revealed with longer exposure time, and several Galactic and extragalactic sources in sky regions not observed in the first survey. The mean position error for all the sources detected with significance above 10 is $40 00 , enough to identify most of them with a known X-ray counterpart and to unveil the nature of most of the strongly absorbed ones, even though they are very difficult to detect in X-rays.

TheBeppoSAX WFC X-ray source catalogue

“…Moreover large fractions of sources have significant (SNR ≥ 7) detections in the 2-5.5, 2-19 and 8-19 keV bands (219, 197 and 133 sources respectively), which have slightly lower percentages (71%, 70% and 64% respectively) of counterparts in the RASS. On the other hand the correlation with the harder INTEGRAL/IBIS Soft γ-ray catalogues (Bird et al 2004(Bird et al , 2006(Bird et al and 2007 give increasing percentages proportionally to the increasing INTEGRAL total exposure and sky coverage (29% with the first, 40% with the second and 53% with the most recent one, using the same 3 radius). If we consider a sample of harder WFC sources (35%), detected (SNR ≥ 10) in the 11-26 keV band, 78% resulted to have a counterpart in the last IBIS catalogue.…”

“…2.3) were automatically identified by the IROS algorithm and then double-checked visually. Sources not identified or misidentified in the reference catalogue were cross checked with literature regarding sources discovered by ASCA, RXTE, BeppoSAX, INTEGRAL, Swift-BAT, XMM (for example see Sugizaki et al 2001;Giommi et al 2000;Bird et al 2006Bird et al , 2007Markwardt et al 2005, XMM-SSC 2003, 2006). Moreover we checked and updated, when necessary, source classifications.…”

“…It contains more information on variability over long time scale in the hard X-ray band than for example the ROSAT all-sky survey catalogues, the ASCA 0.7-10 keV (Sugizaki et al 2001) and the first three INTEGRAL-IBIS low galactic latitude surveys (Bird et al 2004;Bird et al 2006;Revnivtsev et al 2004) and the high galactic latitude survey of the Swift-BAT (Markwardt et al 2005), and comparable with the last INTEGRAL-IBIS survey (Bird et al 2007). …”

INTEGRAL observations of TeV plerions

“…No indication for an extended emission in hard X-rays from the Vela X region is apparent (see also Horns et al, [14]. The X-ray luminosities -except for PSR J1420-6048 -are based on the power law values given in the latest INTEGRAL Reference Catalogue Version 26 [17]. ( * ) Only a estimation for the X-ray flux and thus for the X-ray luminosity is possible due to the faint detection.…”

INTEGRAL/IBIS 7-year All-Sky Hard X-Ray Survey

“…The high sensitivity and relatively good angular resolution of its instruments, in particular the coded-mask telescope IBIS (Ubertini et al 2003), makes surveying the sky in hard X-rays one of the primary goals of INTEGRAL. The main scientific results and source catalogs have been reported in many relevant papers: Revnivtsev et al (2003dRevnivtsev et al ( , 2006, , Krivonos et al (2005b, Bird et al (2004Bird et al ( , 2006Bird et al ( , 2007Bird et al ( , 2010, Bassani et al (2006), Bazzano et al (2006), Sazonov et al (2007), Beckmann et al (2009).…”