Discovery of an Apparent Nova in M81 and an Increase of H-alpha Emission from PNV J09553488+6910194

ATel #6009; K. Hornoch (Astronomical Institute, Ondrejov, Czech Republic), O. Vaduvescu, (ING, La Palma, Spain), H. Stoev (ING, La Palma and Centro de Astrobiologia INTA-CSIC, Madrid, Spain)
on 24 Mar 2014; 23:17 UT
Credential Certification: Allen W. Shafter (aws@nova.sdsu.edu)

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We report the discovery of an apparent nova in M81 on a co-added 2000-s narrow-band H-alpha CCD image taken with the 2.5-m Isaac Newton Telescope (INT) + WFC at La Palma under ~1.5" seeing on 2014 Mar. 18.966 UT. The new object is easily visible on the co-added image (see the finding chart linked below), but is not present on numerous narrow-band H-alpha archival images from the INT down to limiting magnitude as faint as H-alpha = 22.3. On Mar. 18.963 UT we also obtained Sloan r'-band images which helped us to classify the object.

The new object designated PNV J09561209+6902134 = M81N 2014-03a? is located at R.A. = 9h56m12s.09, Decl. = +69o02'13".4 (equinox 2000.0), which is 208.7" east and 101.7" south of the center of M81.

The photometry obtained with the INT + WFC for the PNV J09561209+6902134 and for the M81 nova candidate PNV J09553488+6910194 (see ATel #5918) is summarized in the following table:

 
                         2014 03 18.963    2014 03 18.966 
 
       Object             Sloan r' mag      H-alpha mag 
 
PNV J09561209+6902134     21.1 +/- 0.1     19.40 +/- 0.09 
PNV J09553488+6910194     22.5 +/- 0.25    20.5 +/- 0.15 

After the discovery of the PNV J09561209+6902134, we found prediscovery detections on images taken with the 0.65-m telescope at Ondrejov and the 2.5-m INT. The nova was first detected on Feb. 18.198 UT at unfiltered magnitude (using R-band magnitudes from comparison stars) of 22.6 ± 0.4. Its maximum unfiltered magnitude of 19.6 ± 0.15 reached on Feb. 23, strong H-alpha emission observed in the current INT data, and overall brightness evolution are fully consistent with the classification of the PNV J09561209+6902134 as nova in M81.

Strong H-alpha emission typical for evolved nova is now observed in the INT data also for the PNV J09553488+6910194, which is consistent with its previous classification (ATel #5918).

This work is based on observations made with the Isaac Newton Telescope operated on the island of La Palma by the ING in the Spanish Observatorio del Roque de los Muchachos.

Finding chart