Photometry of M31 Nova AT 2025agmm
ATel #17542; C. Gobat, K. J. Casciotti, J. C. Horst, R. M. Quimby, A. W. Shafter (SDSU), K. Hornoch (Ondrejov), H. Kucakova (Charles University), R. Fidrich, T. Tordai (HAA/VSS)
on 14 Dec 2025; 21:25 UT
Distributed as an Instant Email Notice Novae
Credential Certification: Allen W. Shafter (ashafter@sdsu.edu)
Subjects: Optical, Nova, Transient
We report multi-color photometry of the M31 nova AT 2025agmm (= PNV J00421476+4117284, Vend78) discovered by R. Fidrich on 2025 Dec 11.776 UT. Our follow-up observations of the nova, which is designated by us as M31N 2025-12b, were taken with the Mount Laguna Observatory 40-in reflector and the Danish 1.54-m telescope at La Silla, and are given below.
Date [UT] | Exposure | Mag | Err | Filter | Telescope
2025 Dec. 13.025 | 6x60s | 16.83 | 0.03 | R | 1.54-m
2025 Dec. 13.299 | 3x180s | 16.97 | 0.13 | B | 40-in
2025 Dec. 13.307 | 4x180s | 16.90 | 0.17 | V | 40-in
2025 Dec. 13.298 | 4x180s | 16.65 | 0.04 | R | 40-in
As with all extragalactic novae, follow-up spectroscopic and photometric observations to confirm the nova's nature and determine its spectroscopic class and rate of decline (speed class) are encouraged.
