IGR J18284-0345: a new hard X-ray transient detected by INTEGRAL

T. Blanchard, V. Beckmann, J. Chenevez, S. Corbel, M. Del Santo, C. Ferrigno, N. Gehrels, D. Gotz, J. A. Kennea, F. Mattana, S. Mereghetti, A. Paizis, L. Sidoli, K. Watanabe, G. Weidenspointner, J. A. Zurita

Research output: Other contributionNet publication - Internet publicationResearch

Abstract

The IBIS/ISGRI and the JEM-X1 instrument aboard INTEGRAL discovered a new X-ray source during an observation of the inner Galactic disk conducted from 2009 March 18 at 18:37 UT to March 19, 6:22 UT. The new source, IGR J18284-0345 was detected at RA=277.114, DEC=-3.764 (J2000) in the 20-40 keV energy band by ISGRI with 6.3 sigma detection significance for 27 ksec on-source exposure time and about 3 sigma in JEM-X1 (3-10 keV; 8 ksec). The flux of the source was about 10 mCrab at 3-10 keV and 6 mCrab in the 10-25 keV and in the 20-40 keV energy band, respectively. No source had been reported in the X-rays at this position previous to this finding within the error circle of 4 arcmin. Analysis of 4.8 Msec of IBIS/ISGRI data on the source position gives a marginal detection of 3.9 sigma, indicating strong source variability. Swift has performed a follow-up observation of the source, starting at 2009 March 20 at 15:58 UT for an effective on source time of 1.9 ksec. Swift/XRT detected one source within the INTEGRAL error circle at RA=277.125, DEC=-3.762 with an uncertainty of 4 arcsec. The spectrum can be fit together with the INTEGRAL data by a black body model with kT = 4.0±0.2 keV. The intrinsic absorption is not well constrained and has been fixed to the Galactic value of NH = 5.6e21 1/cm**2. The model flux of IGR J18284-0345 is 3.5e-11 erg/cm**2/sec and 1.4e-10 erg/cm**2/sec in the 2-10 keV and 2-30 keV band, respectively. No source has been reported within the Swift/XRT error circle and no source is visible in the Swift U, V, and B filter image or on plates of the Second Palomar Observatory Sky Survey (POSS-II).
Original languageEnglish
Publication date21 Mar 2009
Publication statusPublished - 21 Mar 2009
SeriesThe Astronomer´s Telegram
NumberATel #1981

Keywords

  • Transients
  • X-ray
  • Request for Observations

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