Discovery of an Apparent Nova in M81 and H-alpha Confirmation of Four M81 Nova Candidates

ATel #6678; K. Hornoch (Astronomical Institute, Ondrejov, Czech Republic), T. Mocnik, O. Vaduvescu, M. Diaz-Alfaro, F. Lopez (ING, La Palma, Spain), I. Ordonez-Etxeberria (ING, La Palma and Universidad del Pais Vasco, Bilbao, Spain)
on 9 Nov 2014; 18:03 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 1200-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 Nov. 4.205 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 = 21.0. On Nov. 4.209 UT we also obtained Sloan r'-band images which helped us to classify the object.

The new object designated PNV J09553144+6903574 = M81N 2014-11a? is located at R.A. = 9h55m31s.44, Decl. = +69o03'57".4 (equinox 2000.0), which is only 9.3" west and 2.3" north of the center of M81.

The photometry obtained with the INT + WFC for the PNV J09553144+6903574 and for M81 nova candidates PNV J09554328+6902033 (ATel #6599), PNV J09554415+6902557 (ATel #6597), PNV J09555775+6902126 (ATel #6552), and PNV J09552058+6902587 (ATel #6496) is summarized in the following table:

 
                         2014 11 04.205     2014 11 04.209 
 
       Object             H-alpha mag        Sloan r' mag 
 
PNV J09553144+6903574    19.0 +/- 0.2       20.7 +/- 0.4 
PNV J09554328+6902033    19.3 +/- 0.1       21.4 +/- 0.15 
PNV J09554415+6902557    20.1 +/- 0.15      21.4 +/- 0.15 
PNV J09555775+6902126    20.9 +/- 0.15      21.9 +/- 0.2 
PNV J09552058+6902587    20.6 +/- 0.2          > 22.0 

Strong H-alpha emission together with relative faintness in Sloan r'-band (both observed in the INT data) of all the objects (except the PNV J09555775+6902126 which has a bit weaker H-alpha emission, but still consistent with a nova) supports their classification as novae.

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