Discovery of a Probable Nova in M81

ATel #10134; K. Hornoch (Ondrejov), M. Henze (CSIC-IEEC), J. Vrastil, H. Kucakova (Charles University), H. Meusinger, C. Pohl (TLS), S. C. Williams (Lancaster), M. J. Darnley (LJMU), A. Kaur, D. H. Hartmann (Clemson), G. Sala, J. Jose, J. Figueira, P. Sin (UPC-IEEC), M. Hernanz (CSIC-IEEC), A. W. Shafter (SDSU)
on 27 Feb 2017; 14:26 UT
Credential Certification: Martin Henze (henze@ice.cat)

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The M81 nova monitoring collaboration reports the discovery of a probable nova in M81 on a co-added 1800-s unfiltered CCD frame taken on 2017 Feb. 26.928 UT with the 0.65-m telescope at Ondrejov (OND). The candidate was also independently found in 2x120s R filter and 2x600s Hα filter prediscovery images taken with the 2-m Alfred-Jensch-Telescope of the Tautenburg observatory (TLS) on Feb. 24th and was detected on a co-added 3510-s OND unfiltered CCD frame obtained on Feb. 24.119 UT.

The object designated PNV J09555331+6858162 is located at R.A. = 9h55m53s.31, Decl. = +68o58'16".2 (equinox 2000.0), which is 108.2" east and 338.9" south of the center of M81 (see link to discovery image below).

Here we list the observing dates and corresponding photometry:

 
  Date [UT]    |  Mag  | Err  | Filter  | Telescope 
2017-02-19.962 | <21.5 |      | C       | OND 
2017-02-24.119 |  20.8 | 0.3  | C       | OND 
2017-02-24.864 |  21.1 | 0.3  | H-alpha | TLS  
2017-02-24.875 |  21.0 | 0.3  | R       | TLS  
2017-02-26.928 |  20.4 | 0.15 | C       | OND 
 

The OND 0.65-m is a reflecting telescope at the Ondrejov observatory operated jointly by the Astronomical Institute of ASCR and the Astronomical Institute of the Charles University of Prague, Czech Republic. It uses a Moravian Instruments G2-3200 CCD camera (with a Kodak KAF-3200ME sensor and standard BVRI photometric filters) mounted at the prime focus. The 2-m TLS of the Tautenburg observatory, Germany, was operated in Schmidt camera mode using a 2k x 2k CCD with a 0.7 x 0.7 deg field of view. The unfiltered photometry was calibrated against R-band comparison stars from Perelmuter & Racine (1995). The TLS R and Hα magnitudes were both calibrated using the SDSS DR7 photometry catalogue.

Discovery image