INTEGRAL detects a new outburst from the NS LMXB SAX J1750.8-2900

E. Bozzo, E. Kuulkers, A. Paizis, A. Bazzano, R. Wijnands, P. Kretschmar, C. Sanchez-Fernandez, J. Chenevez, M. Del Santo, A. Bodaghee, L Ducci, V. Savchenko, C. Ferrigno

Research output: Other contributionNet publication - Internet publicationResearch


During the observations in the direction of the Galactic Bulge (ATel #438) carried out from 2018 September 18 at 11:55 to 15:36 (UTC), INTEGRAL detected renewed activity from the transient neutron star low mass X-ray binary (NS LMXB) SAX J1750.8-2900. The source is detected in the IBIS/ISGRI mosaic at a flux of 23+/-3 mCrab in the 20-40 keV energy band and 29+/-4 mCrab in the 40-80 keV energy band. The source is also detected by the JEM-X telescopes. The estimated fluxes from the JEM-X mosaics are 20+/-3 mCrab in the 3-10 keV energy band and 16.0+/-9.5 mCrab in the 10-25 keV energy band. A preliminary analysis of the IBIS/ISGRI spectrum revealed that the hard X-ray emission from the source could be characterized by a power-law model with a photon index of 3.5+/-1.2 (90% c.l.). The measured 20-100 keV flux from the spectral fit is 5E-10 erg/cm^2/s (no spectral analysis of the JEM-X data has been carried out due to the calibration uncertainties affecting the near-real time data). No type-I X-ray bursts were observed in the JEM-X lightcurves extracted with a time resolution of 2 s in the 3-20 keV energy band. The most recent hard X-ray outburst from this source was announced in 2015 (ATel #8058). Further INTEGRAL observations toward the direction of the source are already planned in the coming days. Multi-wavelength observations in other energy domains are also encouraged, as well as observations to characterize the source soft X-ray emission (< 3 keV).
Original languageEnglish
Publication date19 Sep 2018
Publication statusPublished - 19 Sep 2018
SeriesThe Astronomer's telegram
NumberATel #12048


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