SRG/ART-XC detects an increased activity from IGR J17379-3747 - 468 Hz AMXP/burster

ATel #14051; Mereminskiy I., Lutovinov A., Semena A., Molkov S., Filippova E., Tkachenko A., Lapshov I. on behalf of ART-XC team (IKI RAS, Moscow, Russia)
on 29 Sep 2020; 18:06 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Ilya Mereminskiy (i.a.mereminskiy@gmail.com)

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During the second consecutive all-sky survey the ART-XC telescope onboard the SRG observatory scanned over the position of a known Galactic X-ray binary IGR J17379-3747 (==IGR J17380-3749==XTE J1737-376) on Sep. 29. This source demonstrates type-I bursts (Chelovekov, Grebenev 2010) and hosts a very rapidly spinning neutron star (ATel#11507). Last source outburst happened in 2018, the source was observed by different X-ray observatories (see Sanna et al., 2018, Bult et al, 2019 for details) and also was detected in radio (ATel#11487).

ART-XC found a bright source at RA,Dec=264.4994, -37.7699 (J2000, 90% uncertainty radius is 30"), which is 18" off the position of IGR J17379-3747. Given the positional coincidence and lack of other historical X-ray transients at this position we identified the ART-XC source with IGR J17379-3747. The observed flux is about (6.0±1.2)x10^-11 erg/cm²/s in the 4-12 keV band, that corresponds to the luminosity of 5x10³⁵ erg/s at the tentative distance of 8.5 kpc to IGR J17379-3747. No strong variability was seen during three transits over the ART-XC field of view over eight hours. We, therefore, conclude that the source now undergoes a new outburst.

Observations in all wavelengths are strongly encouraged.

ART-XC is an X-ray telescope on board the SRG observatory. The telescope is designed and built by IKI (Russian Academy of Sciences) and RFNC, with the participation from MSFC/NASA. The SRG observatory was launched from the Baikonur cosmodrome on 13 July 2019 by a Proton rocket, now ART-XC performing its second all-sky survey.