Independent Discovery of an Apparent Nova in M31, AT 2025agwf

ATel #17543; K. Hornoch (Ondrejov), H. Kucakova (Charles University), A. W. Shafter (SDSU), R. Fidrich (HAA/VSS)
on 15 Dec 2025; 19:16 UT
Distributed as an Instant Email Notice Novae
Credential Certification: Allen W. Shafter (ashafter@sdsu.edu)

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We report the independent discovery of an apparent nova found during our survey of the central region of M31. The object was discovered on a co-added 360-s R-band CCD frame taken on 2025 Dec. 15.023 UT with the Danish 1.54-m telescope at La Silla Observatory.

The object was independently discovered on Dec. 14.746 UT by F. Castellani et al. and designated as AT 2025agwf = PNV J00431764+4114201 = Vend79.

The object was designated by us as M31N 2025-12c and is located at R.A. = 0h43m17s.64, Decl. = +41o14'19".8 (equinox 2000.0), which is 375.7" east and 108.7" south of the center of M31 (see link to discovery image below).

The following R-band magnitudes were obtained using the Danish 1.54-m telescope (DK154):

 
  Date [UT]    |  Mag   | Err  | Filter  | Telescope 
 
2025-12-13.025 | >19.8  |      | R       | DK154 
2025-12-15.023 |  16.34 | 0.03 | R       | DK154 
 

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. This work is based on data collected with the Danish 1.54-m telescope at the ESO La Silla Observatory.

Discovery image