NICER follow-up of rapidly variable and rising nuclear transient AT2019pev
ATel #13132; Erin Kara (MIT), Dheeraj Pasham (MIT), Keith Gendreau (NASA/GSFC), Zaven Arzoumanian (NASA/GSFC)
on 26 Sep 2019; 12:46 UT
Credential Certification: Dheeraj Pasham (drreddy@mit.edu)
Subjects: X-ray, AGN, Transient
We report NICER follow-up observations of the bright, nuclear transient AT2019pev/ZTF19abvgxrq/Gaia19eby (ATel #13127), which shows a strong blue continuum and Bowen fluorescent lines, similar to the new class of transients identified in Trakhtenbrot et al., 2019. NICER observed the source on 2019 September 25 (just 14 hours after ATel#13127 was posted) and found a 0.3-2 keV X-ray flux of ~1e-11 erg/cm2/s. This is nearly 10x brighter than the X-ray flux measured by Swift/XRT just one day earlier (ATel #13127), and ~100x brighter than the archival ROSAT detection.
NICER observed AT2019pev for roughly 2 ks and detects the source above the background in the 0.3-2.5 keV range. The spectrum is well described with a 150 eV blackbody and a powerlaw with photon index fixed at 2 with no additional intrinsic absorption. Accounting for Galactic absorption, we find an unabsorbed flux of 2e-11 erg/cm2/s or a luminosity of 4e44 erg/s in the 0.3-2.5 keV band (assuming a redshift of 0.096).
The observations were made over a ~3 hour time-frame, during which time the source flux varied at the ~20% level (between 14 and 11 counts/sec). NICER continues to monitor this quickly evolving source.
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.
