NuSTAR observations of IGR J21347+4737 reveal that the source does not appear to be entering outburst
ATel #14291; Sean N. Pike, Fiona A. Harrison (SRL/Caltech)
on 25 Dec 2020; 07:16 UT
Credential Certification: Sean Pike (spike@caltech.edu)
Subjects: X-ray, Binary, Neutron Star, Transient, Pulsar
On December 6, 2020, the BeXRB IGR J21347+4737 was reported to have increased in flux to 7x10^-11 erg/cm2/s in the 4-12 keV band, compared to 1.3x10^-11 erg/cm2/s on June 2, 2020, based on ART-XC observations (ATel #14247). We performed a follow-up observation of the source with NuSTAR which took place between UTC 13:20 December 17, 2020 and 04:30 December 18, 2020. We report a decreased 4-12 keV source flux of 1.49(2)x10^-11 erg/cm2/s. This indicates that the source may not in fact be entering a period of outburst as was previously inferred based on the elevated flux measured by ART-XC.
Additionally, we report the detection of coherent pulsations with period 322.7(6) seconds at reference time MJD 59200.57. Reig and Zezas (2014) reported a pulse period of 320.35(6) at approximately MJD 56620.78, giving a secular spin-down of Pdot = 1.1(3)x10^-8 s/s. We find a pulse fraction of PF = 27 +/- 2 % for the energy range 3-78 keV.
Further monitoring of the source in the X-ray band is encouraged in order to understand its long-term flux variability.
