Discovery of Three Probable Novae in M31

ATel #16605; K. Hornoch (Astronomical Institute, Ondrejov, Czech Republic), M. Myslivec (HVBO, Czech Republic), H. Kucakova (Astronomical Institute, Charles U., Prague, Czech Republic), A. W. Shafter (SDSU)
on 29 Apr 2024; 19:09 UT
Distributed as an Instant Email Notice Novae
Credential Certification: Allen W. Shafter (ashafter@sdsu.edu)

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We report the discovery of three probable novae in M31 on a co-added 6600-s H_alpha CMOS frame taken on 2024 Apr. 28.047 UT with the 0.4-m telescope at Belec nad Orlici. M31 was observed at very low elevation under bad seeing conditions. All the three new objects are visible also on a confirmation 6600-s H_alpha CMOS frame taken on 2024 Apr. 29.047 UT with the same instrumentation. There is nothing visible at the positions of the three objects down to H_alpha = 19.6 mag on a high-quality image taken on 2021 Dec. 22.772 UT with the same instrumentation. On Apr. 29.096 UT we also took a co-added 960-s R-band CCD image of the PNV J00430814+4110243 = M31N 2024-04c using the 0.65-m telescope at Ondrejov.

Designations, positions, and offsets of the new objects from the M31 center are summarized in the following table:

 
  TOCP designation    CBAT designation  R.A. (J2000)  Dec. (J2000)  Offset R.A.  Offset Dec. 
 
PNV J00432199+4132450  M31N 2024-04b    00 43 21.99   +41 32 45.0    423.8" E     996.5" N 
PNV J00430814+4110243  M31N 2024-04c    00 43 08.14   +41 10 24.3    268.7" E     344.2" S 
PNV J00411379+4105499  M31N 2024-04d    00 41 13.79   +41 05 49.9   1022.1" W     618.6" S 
 

The photometry is summarized here:

 
 
                        2024 04 28.047    2024 04 29.047    2024 04 29.096 
 
       Object             H_alpha mag      H_alpha mag           R mag 
 
PNV J00432199+4132450     16.0 +/- 0.1     16.2 +/- 0.1 
PNV J00430814+4110243     17.3 +/- 0.2     16.8 +/- 0.15     17.1 +/- 0.15          
PNV J00411379+4105499     17.2 +/- 0.2     17.4 +/- 0.25          
 

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