Independent Discovery of a Probable Nova in M31

ATel #17265; K. Hornoch (Ondrejov), H. Kucakova (Charles University), A. W. Shafter (SDSU)
on 3 Jul 2025; 19:15 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 a probable nova found during our survey of the central region of M31. The object was discovered on a co-added 420-s R-band CCD frame taken on 2025 Jul. 2.448 UT with the Danish 1.54-m telescope at La Silla and confirmed using the same instrumentation on Jul. 3.446 UT.

The object was independently discovered on Jul. 3.108 UT by R. Fidrich and T. Tordai and designated as PNV J00425628+4114512 = AT 2025qdc.

The object was designated by us as M31N 2025-07a and is located at R.A. = 0h42m56s.06, Decl. = +41o14'52".0 (equinox 2000.0), which is 132.3" east and 76.5" 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 at La Silla (DK154) and the 0.65-m telescope at Ondrejov (D65):

 
  Date [UT]    |  Mag   | Err  | Filter  | Telescope 
 
2025-06-30.951 | >19.7  |      | R       | D65 
2025-07-02.448 |  19.1  | 0.15 | R       | DK154 
2025-07-03.446 |  18.23 | 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.

Discovery image