INTEGRAL detection of the new transient MAXI J1631-479

ATel #12418; Onori F. (INAF-IAPS Roma, Italy), Fiocchi M. (INAF-IAPS Roma, Italy), Lepingwell V. A. (Univ. of Southampton, UK), Bird A. J. (Univ. of Southampton, UK), Chenevez J. (DTU Space, Denmark), Bazzano A. (INAF-IAPS Roma, Italy), Natalucci L. (INAF-IAPS Roma, Italy), Ubertini P. (INAF-IAPS Roma, Italy), Sguera V. (INAF-OAS Bologna, Italy), Malizia A. ( INAF-OAS, Bologna, Italy), Charles P. (Univ. of Southampton, UK) and Masetti N. (INAF-OAS Bologna, Italy)
on 24 Jan 2019; 16:09 UT
Credential Certification: Francesca Onori (francesca.onori@inaf.it)

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During a recent INTEGRAL observation of the Galactic Plane Scan (PI: Dr. A. Bazzano), the IBIS/ISGRI instrument detected a bright X-ray source at coordinates consistent with MAXI J1631-479. The source was first detected by MAXI/GSC at 04:33 UT on December 21, 2018 (K. Kobayashi et al., ATel #12320) and it was identified as a new X-ray black hole candidate by Hiromasa Miyasaka et al., (ATel #12340). A radio counterpart of the source was observed by the Australia Telescope Compact Array (ATCA) at 5.5 and 9 GHz (T.D. Russel et al., ATel #12396).
The source was detected by IBIS/ISGRI during scans performed in revolution 2048 (between 2019-01-21 13:31:40 UTC and 2019-01-23 16:21:58 UTC) in the 22-60 keV energy range at the position RA(J2000)=247.814 DEC(J2000)=-47.800, 0.5’ error radius for an effective exposure time of 1.4 ks. The 22-60 keV flux was measured at 265.2±3.7 mCrab.
We obtained a spectrum in the 30-110 keV range that is well modelled by a power-law model (with a reduced chi2 of 1.2 for 10 degrees of freedom) with Γ= 2.9±0.1 and a F_20-100keV = 4.41±0.15×10^-9 erg cm^-2s^-1 for a net exposure time of 16.5 ks.
MAXI J1631-479 was not within the field of view of JEM-X instruments.
All the data have been analyzed using the Offline Software Analysis version 11.0 (OSA11).
The source field will be observed again during the next days in the framework of the Galactic Plane Scan program (PI: Dr. A. Bazzano).
Results from the Galactic Plane Scanning are made publicly available at: http://gps.iaps.inaf.it