Brightening of 3C 279 observed by INTEGRAL at hard X-rays

ATel #7648; E. Bottacini (Stanford University), C. Ferrigno, S. Fotopoulou (ISDC, University of Geneva), W. Collmar (Max-Planck-Institut fuer extraterrestrische Physik), E. Pian (INAF Bologna, SNS Pisa)
on 17 Jun 2015; 08:44 UT
Credential Certification: Carlo Ferrigno (Carlo.Ferrigno@unige.ch)

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The flat spectrum radio quasar 3C 279 at z=0.536 is flaring in the gamma-ray band, as announced by AGILE and FERMI (ATels #7631 and #7633); a Swift/XRT follow-up showed a significant brightening in the X-ray band as well (ATel #7639). Here, we report that 3C 279 is detected also by INTEGRAL during the current deep Coma region monitoring.

The source is observed by IBIS/ISGRI telescope at large off-axis angle during the satellite revolution 1553 (from 2015-06-15 04:38 to 2015-06-16 05:13 UTC) with a statistical detection significance of 6.4σ in the 20-40 keV energy band, for an equivalent on-axis exposure of 5 ks. The flux is 10±2 mCrab corresponding to 8×10^-11 erg/cm²/s. At higher energy, in the 40-80 keV band, the 5σ upper limit on the source flux is 9×10^-11 erg/cm²/s. The source is not observed by JEM-X and by OMC because outside their field of view.

During the previous INTEGRAL observation (2015-06-12 15:05 - 2015-06-14 17:37 UTC), the 5σ upper limit in the 20-40 keV energy band was 9mCrab. INTEGRAL will be monitoring the Coma sky region during the following days according to the available on-line schedule.