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Discovery of four new hard X-ray sources in the Circinus and Carina region by INTEGRAL

ATel #684; L. Kuiper (SRON), S. Keek (SRON), W. Hermsen (SRON/Amsterdam), P. G. Jonker (SRON/CfA), D. Steeghs (CfA)
on 4 Jan 2006; 09:14 UT
Credential Certification: Lucien Kuiper (L.M.Kuiper@sron.nl)

Subjects: Optical, X-ray, Gamma Ray, >GeV, AGN, Binary, Neutron Star, Quasar

Referred to by ATel #: 783

We report the discovery with IBIS ISGRI of three new hard X-ray (>20 keV) sources in the Circinus region during INTEGRAL observations of PSR B1509-58. These observations have been performed between 2004, July 24 and 2005, March 3, totalling an exposure time of about 900 ks. Positional and flux information is given in the table presented below along with the names of potential (low-energy) counterparts found within the error circles. Two of the new sources, IGR J14536-5522 and IGR J14515-5542, are located within one square degree together with IGR J14493-5534 (see Revnivtsev et al. 2005; astro-ph/0508155). The latter source was also detected significantly up to about 65 keV (7.8 sigma in 20-65 keV band, 1.65 +/- 0.21 mCrab) during our observations. We further report the discovery of a new source in the Carina region, IGR J10101-5654, during a deep 2 Ms INTEGRAL observation of the Carina region performed between 2004, May 9 and June 14. This new source, located in the galactic plane and near INTEGRAL source IGR J10109-5746 (Revnivtsev et al. 2005, see astro-ph/0508155; also known as SWIFT J1010.1-5747, see ATEL#669), is positioned within the 2-sigma location contour of high-energy gamma-ray source 3EG J1014-5705. No evident low-energy counterpart could be found in the SIMBAD and HEASARC databases. IGR J10109-5746 is also detected significantly (9.9 sigma in 20-40 keV band, 1.3 +/- 0.13 mCrab) in this 2 Ms Carina region exposure. We also confirm the SWIFT BAT detection of SWIFT J0917.2-6221 identified by J. Tueller et al. (ATEL#669) with a Sy 1 galaxy. The measured IBIS ISGRI 20-60 keV flux is 1.40 +/- 0.18 mCrab (7.9 sigma)

INTEGRAL Name    Alpha(2000)  Decl.(2000)   Pos.  20-65 keV flux   Potential Counterpart(s)  
Error mCrab

IGR J14536-5522 14 53 37.5 -55 22 22.7 2.3' 2.27 +/- 0.21 1RXS J145341.1-552146/
1RXS J145349.4-552144
IGR J14515-5542 14 51 32.9 -55 42 16.3 3.2' 1.67 +/- 0.21 1RXS J145132.4-554041/
LEDA 3079667
IGR J16351-5806 16 35 10.4 -58 06 4.4 3.2' 3.10 +/- 0.36 LEDA 58547/ESO 137-34 (Sy 2)
IGR J10101-5654 10 10 07.8 -56 54 46.4 2.2' 1.40 +/- 0.12 ......
Optical observations of IGR J14536-5522, IGR J14515-5542, IGR J14493-5534 and IGR J10101-5654 are planned on 2006 Jan 4/5 with the Magellan Baade telescope at Las Campanas.