Prediscovery detection of AT2021afpi/MASTER OT J030227.28+191754.5, 8 hours before the IceCube-211125A neutrino event
ATel #15081; K. Sarneczky, J. Vinko, L. Kiss (Konkoly Observatory)
on 1 Dec 2021; 00:35 UT
Credential Certification: Jozsef Vinko (vinko@astro.as.utexas.edu)
Subjects: Optical, Cataclysmic Variable
Referred to by ATel #: 15115
We report prediscovery detection of AT2021afpi/MASTER OT J030227.28+191754.5 (ATel #15067, #15069, #15073, #15074, #15078, #15079) on stacked, unfiltered CCD frames taken with the 10560x10560 STA 1600LN CCD camera on the 0.6/0.9m Schmidt telescope at Piszkesteto Station of Konkoly Observatory
at 2021-11-24 21:53 UT, 8.5 hours before the IceCube-211125A neutrino event. The total exposure time was 24 sec.
Forced photometry at the transient position resulted in a clear detection at 19.13 +/- 0.22 mag tied to r-band SDSS DR16 photometry of nearby comparison stars. This is ~1 magnitude brighter than the combined r-band SDSS photometry of the transient and its close optical companion, which were unresolved on our CCD frames.
The detection of AT2021afpi already brightening at 8.5 hours before the IceCube-211125A trigger suggests that the transient is probably unrelated to the neutrino event. This is consistent with the classification of AT2021afpi as a WZ Sge-type dwarf nova (Isogai et al, ATel #15074), since neutrino emission from such objects is not likely.
