Discovery of two nova candidates in M81

ATel #9792; S. C. Williams (Lancaster), K. Hornoch (Ondrejov), M. Henze (CSIC-IEEC), M. J. Darnley (LJMU), H. Kucakova (Charles University), A. Kaur, D. H. Hartmann (Clemson), G. Sala, J. Jose, J. Figueira, P. Sin (UPC-IEEC), M. Hernanz (CSIC-IEEC), A. W. Shafter (SDSU), H. Meusinger (TLS)
on 25 Nov 2016; 16:14 UT
Credential Certification: Steven Williams (scw@astro.ljmu.ac.uk)

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The M81 nova monitoring collaboration reports the discovery of two nova candidates in M81. The first, M81N 2016-11b, was discovered at an unfiltered magnitude of 21.5±0.3 on 2016-11-14.171 UT, with the 0.65-m telescope at Ondrejov (OND). We measure the position of M81N 2016-11b to be RA = 9h55m24.06s, Dec. = +69°05'06.0" (J2000, 1σ error 0.3"). The second candidate, M81N 2016-11c, was discovered at a Hα magnitude of 19.8±0.2 on narrow-band images taken with the 2-m Liverpool Telescope (LT) on 2016-11-21.080 UT. We measure the position of M81N 2016-11c to be RA = 9h55m42.034s, Dec. = +69°03'53.16" (J2000; 1σ error 0.3"). We report our photometry for the two nova candidates in the tables below.

M81N 2016-11b:

  Date [UT]    |  Mag  | Err  | Filter   | Telescope  
2016-11-08.183 | <22.0 |      | C        | OND  
2016-11-14.171 |  21.5 | 0.3  | C        | OND  
2016-11-15.016 |  20.6 | 0.3  | C        | OND 
2016-11-21.080 |  19.1 | 0.1  | Hα       | LT 

M81N 2016-11c:

  Date [UT]    |  Mag  | Err  | Filter   | Telescope  
2016-11-14.171 | <22.0 |      | C        | OND  
2016-11-15.016 | <21.5 |      | C        | OND  
2016-11-17.987 | <20.5 |      | R        | TJO 
2016-11-21.080 |  19.8 | 0.2  | Hα       | LT 

The LT (Steele et al. 2004) is a fully robotic 2-m telescope operated on the island of La Palma by Liverpool John Moores University in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias with financial support from the UK Science and Technology Facilities Council. Our observations use the IO:O optical CCD camera of the LT. The Telescopi Joan Oro (TJO) is a 80-cm Ritchey-Chretien F/9.6 telescope at the Observatori Astronomic del Montsec, owned by the Catalan Government and operated by the Institut d'Estudis Espacials de Catalunya, Spain. It uses a Finger Lakes PL4240-1-BI CCD Camera with a Class 1 Basic Broadband coated 2k x 2k chip with 13.5 microns square pixels. 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 unfiltered OND photometry was calibrated against R-band comparison stars from Perelmuter & Racine (1995). The LT and TJO photometry is based on the SDSS DR7 photometry catalogue. The Hα magnitude is defined on the AB system where m_Hα = 0 for f_λ = 2.53 × 10^-9 erg/cm²/s/Å. Through a 90 Å wide filter, this corresponds to a zero point flux of ~2.3 × 10^-7 erg/cm²/s/Å.