No bright optical counterpart to the X-ray transient SRGt J071522.1-191609
ATel #13662; Kirill Sokolovsky (MSU/SAI MSU/ASC Lebedev), Stanislav Korotkiy (Ka-Dar Obs./Astrovert), Aleksandr Beloushkin (Voronezh)
on 24 Apr 2020; 11:18 UT
Credential Certification: Kirill Sokolovsky (kirx@scan.sai.msu.ru)
The X-ray transient SRGt J071522.1-191609 was discovered by
SRG/eROSITA on 2020-04-19. The transient was observed during four
passes through the eROSITA field of view between 01:28 and
17:30 UTC, maintaining a constant brightness in the 0.2-10 keV
band (ATel #13657). SRGt J071522.1-191609 was detected by Swift
on 2020-04-24 with no UV/optical counterpart down to v > 18.31
(Vega magnitudes; ATel #13661).
We imaged the field of SRGt J071522.1-191609 with a wide-field
camera of the NMW survey ( http://scan.sai.msu.ru/nmw/ ) on
2020-04-19 17:37:22 UT, seven minutes after the final SRG/eROSITA
pass. No optical counterpart brighter than magnitude 14.0
(unfiltered with V zero-point) is visible at the X-ray transient
position. The images (3x20sec frames) were obtained with an
ST-8300M CCD camera attached to a Canon 135mm f/2.0 telephoto lens
installed on a computer-controlled mount.
WCS-calibrated FITS images of the field containing SRGt J071522.1-191609
