Discovery of three nova candidates in M81

ATel #11026; S. C. Williams (Lancaster), K. Hornoch (Ondrejov), H. Kucakova (Ondrejov), M. Henze (SDSU), G. Sala, J. Jose, J. Figueira, P. Sin (UPC-IEEC), H. Meusinger (TLS), M. J. Darnley (LJMU), A. Kaur, D. H. Hartmann (Clemson), A. W. Shafter (SDSU)
on 30 Nov 2017; 13:45 UT
Credential Certification: Steven Williams (scw@astro.ljmu.ac.uk)

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The M81 nova monitoring collaboration reports the discovery of three M81 nova candidates in Hα imaging from the 2-m Liverpool Telescope (LT). The first, M81N 2017-10a, was discovered on 2017-10-30.14 UT at RA = 9h55m31.13s, Dec. = +69°05'22.3" (J2000, 1σ error 0.2"). The second, M81N 2017-10b, was discovered on 2017-11-01.13 UT at RA = 9h55m25.97s, Dec. = +69°01'05.1" (J2000, 1σ error 0.2"). The third, M81N 2017-11a, was discovered on 2017-11-18.12 UT at RA = 9h55m40.38s, Dec. = +69°01'20.8" (J2000, 1σ error 0.2"). The photometry of the three candidates from the LT and the 0.65-m telescope at Ondrejov (OND) are presented below.

Photometry of M81N 2017-10a:

 
  Date [UT]   |  Mag  | Err | Filter | Telescope 
2017-10-10.21 | <20.8 |     | Hα     | LT 
2017-10-30.14 |  20.9 | 0.3 | Hα     | LT 
2017-11-01.13 |  20.8 | 0.2 | Hα     | LT 
2017-11-04.19 |  21.8 | 0.4 | C      | OND 
2017-11-11.16 | <21.7 |     | C      | OND 
2017-11-18.12 |  20.4 | 0.2 | Hα     | LT 

Photometry of M81N 2017-10b (Note this was discovered in images taken 2017-11-01.13, but already present in data taken 2017-10-30.14 UT):

 
  Date [UT]   |  Mag  | Err | Filter | Telescope 
2017-10-10.21 | <21   |     | Hα     | LT 
2017-10-30.14 |  21.2 | 0.3 | Hα     | LT 
2017-11-01.13 |  20.3 | 0.2 | Hα     | LT 
2017-11-04.19 |  21.2 | 0.3 | C      | OND 
2017-11-11.16 | <21.4 |     | C      | OND 
2017-11-18.12 |  20.6 | 0.2 | Hα     | LT 

Photometry of M81N 2017-11a:

 
  Date [UT]   |  Mag  | Err | Filter | Telescope 
2017-11-01.13 | <20.8 |     | Hα     | LT 
2017-11-04.19 | <21.9 |     | C      | OND 
2017-11-11.16 | <21.7 |     | C      | OND 
2017-11-18.12 |  20.7 | 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 LT 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. 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.