NICER observations of new outburst from the black hole candidate XTE J2012+381

ATel #15829; W. Iwakiri (Chiba U.), M. Shidatsu (Ehime. U), K. C. Gendreau, Z. Arzoumanian (NASA/GSFC), A. Sanna (Univ. of Cagliari), T. Mihara (RIKEN)
on 27 Dec 2022; 15:15 UT
Credential Certification: Wataru Iwakiri (wataru.iwakiri@riken.jp)

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We report on initial NICER observations of new outburst from the black hole candidate XTE J2012+381 discovered by MAXI at Dec 25 21:27 UT (ATel #15826) and confirmed by Swift (ATel #15827).
The observation began at 2022 Dec 26 19:01 UT, and ended at 2022 Dec 26 23:39 UT, with about 6000 sec of exposure. During this observation, the X-ray flux increased by about 15%. The average X-ray flux in the 1 - 10 keV band is about 1.2 x 10^-9 erg/s/cm². The average power spectrum shows that there is no significant periodic feature. The energy spectrum is reproduced by an absorbed multi-color disk blackbody plus power-law model. The best-fit hydrogen column density is 1.33 +/- 0.02 x 10²² cm^-2. The power-law component is dominant in most of the NICER energy band and has a photon index of 2.57 +/- 0.04, which is larger than the typical values in the low/hard state. The inner disc temperature is estimated to be relatively small, 0.44 +/- 0.01 keV. These results suggest that the source is in the intermediate state.
NICER will continue to monitor this source. Multi-wavelength followup observations are strongly encouraged.

NICER is a 0.2-12 keV X-ray telescope operating on the International Space Station. The NICER mission and portions of the NICER science team activities are funded by NASA.