INTEGRAL detects re-brightening of the black hole candidate MAXI J1535-571

V. A. Lepingwell*, A. Bazzano, A. J. Bird, J. Chenevez, M. Fiocchi, V. Sguera

*Corresponding author for this work

Research output: Other contributionNet publication - Internet publicationResearch


During the recently recommenced Galactic Plane Scan program (PI: Dr A. Bazzano), the IBIS/ISGRI instruments onboard the INTEGRAL observatory observed a clear re-brightening of MAXI J1535-571, a bright black hole candidate in a low-mass X-ray binary (Y Xu et al. 2012 ApJ, 852, 2). MAXI J1535-571 was first detected by Swift and MAXI in outburst in early September 2017 (GCN #21792, ATel #10699) where it reached ~5 Crab in the MAXI/GSC band, making it one of the brightest black hole binary candidates observed.

The source was detected by IBIS/ISGRI during scans performed early in revolution 1979 (between 2018-07-22 00:28:13 and 2018-07-23 11:11:35) and was observed to be brightening strongly.

In the analysis of the stacked data from the revolution, IBIS/ISGRI data detected the source at RA = 233.851, Dec = -57.240, 3' error radius, and with an overall detection significance in the 22-60 keV band of 8.6 sigma. The flux was measured in the 22-60 keV as 1.72 +/- 0.2^-10 erg cm^-2 s^-1 (15.89 +/- 1.84 mCrab), with an effective exposure time of 5.2 ks.

Further Galactic Plane Scan observations are due in the coming days and we will continue to monitor this source. Other observations to observe the developing outburst in all wavelengths are strongly encouraged.
Original languageEnglish
Publication date24 Jul 2018
Publication statusPublished - 24 Jul 2018
SeriesThe Astronomer's telegram
NumberATel #11884

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