Central Bureau for Astronomical Telegrams

CBAT "Transient Object Followup Reports"

PNV J00435642+4113559

PNV J00435642+4113559   2023 10 26.6192*  00 43 56.42 +41 13 55.9  21.2 V  813E 132S  M31       9 2

2023 10 26.6192

Jingyuan Zhao and Weihao Wang, report the discovery of a possible nova. Discovery image using Johnson V filter, exposured 600-s, obtained by 0.5-m f/6.8 Lulin-ASIAA Telescope for Transients and Education (LATTE) at Lulin Observatory (D35) around 2023 Oct. 26.61924 UT, mag = 21.2 V. The transient is also visible on another Johnson R filter image taken by LATTE in the same night (2023 Oct. 26.62627, exposured 600-s, mag = 20.4 R), and it is significantly brighter in the image taken by LATTE on October 30th (2023 Oct. 30.60508, exposured 600-s, mag = 20.1 V; 2023 Oct. 30.61675, exposured 600-s, mag = 19.2 R). The transient is faintly visible on images taken by LATTE a few days earlier. No object can be seen at this location on the PanSTARRS DR1 image. We also reported the transient to TNS, and it was named AT 2023wck (see https://www.wis-tns.org/object/2023wck ). Images can be found at https://www.wis-tns.org/system/files/uploaded/general/tns_2023wck_atrep_192127.jpg

2023 11 06.23624

Based on the ALeRCE ZTF photometry (see https://alerce.online/object/ZTF23abnpynv ) show symmetry demonstrated, we suggest that AT 2023wck may be a gravitational microlensing event in M31. Considering that the candidate has become very faint, deep photometry and spectroscopic observations are encouraged.