H-alpha Confirmation, Astrometry and Photometry of Two Novae in M31

ATel #5172; K. Hornoch (Astronomical Institute, Ondrejov, Czech Republic), O. Vaduvescu (ING, La Palma, Spain), A. Gonzalez (ING, La Palma and University of La Laguna, Tenerife, Spain)
on 27 Jun 2013; 22:48 UT
Credential Certification: Allen W. Shafter (aws@nova.sdsu.edu)

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We obtained five 120-s narrow-band H-alpha and three 90-s R-band CCD frames of the central region of M31 on 2013 June 27.189 and 27.193 UT, respectively, with the 2.5-m Isaac Newton Telescope + WFC at La Palma under ~2.0" seeing. The single frames were co-added and the co-added images were used for photometry and astrometry of the two recently discovered and spectroscopically unconfirmed M31 nova candidates, namely the PNV J00424894+4115163 (ATel #5133) and PNV J00425987+4120379 (ATel #5157).

Precise astrometry obtained from the co-added 600-s H-alpha image gave R.A. = 0h42m48s.91, Decl. = +41o15'16".9 (equinox 2000.0), which is 51.7" east and 51.6" south of the center of M31 for the PNV J00424894+4115163 and R.A. = 0h42m59s.88, Decl. = +41o20'37".9, which is 175.3" east and 269.4" north of the center of M31 for the PNV J00425987+4120379.

The following magnitudes were obtained:

 
 
  TOCP designation     CBAT designation   H-alpha mag         R mag 
 
PNV J00424894+4115163   M31N 2013-06a?   16.49 +/- 0.08   19.3 +/- 0.25 
PNV J00425987+4120379   M31N 2013-06b?   16.57 +/- 0.05   17.09 +/- 0.05 
 

Strong H-alpha emission together with the relative faintness of the PNV J00424894+4115163 in the R-band confirms nova nature of the object, while relative weaker excess in H-alpha emission observed in the PNV J00425987+4120379 is typical for young nova, which is consistent with its time of outburst (ATel #5157).

This work is based on observations made with the Isaac Newton Telescope (INT) operated on the island of La Palma by the Isaac Newton Group (ING) in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias (IAC).