New slow-evolving variable or optical nova candidate in the M 31 disk

ATel #8267; G. Sala (UPC-IEEC), M. Henze (CSIC-IEEC), J. Jose, J. Figueira (UPC-IEEC), M. Hernanz (CSIC-IEEC)
on 10 Nov 2015; 15:13 UT
Credential Certification: Gloria Sala (gloria.sala@upc.edu)

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We report the discovery of a possible slow-evolving nova or variable in the disk of M31. The new candidate was first significantly detected on 2015 November 06.99 with an R magnitude of 19.0±0.2 and remained at a similar magnitude in the following nights. Upon inspecting previous observations we found that the object slowly emerged during October 2015 until it crossed our detection threshold in early November. The last non-detection in deep images of our monitoring is on September 21, with an upper limit of R > 20.9.

The position of the new object is RA = 00h44m28.4s, Dec = +41o32'32.9" (J2000, accuracy 0.2"), which is 1173" east and 985" north of the core of M31. Nothing is visible at this position on the images of the Local Group Galaxies Survey (LGGS, Massey et al. 2006, AJ, 131, 2478) and no object is present in the VizieR/CDS data base. Spectroscopic follow-up observations are encouraged.

The candidate was detected in sets of 4x200s stacked R filter CCD images, obtained with the 80 cm Ritchey-Chretien F/9.6 Joan Oro telescope at Observatori Astronomic del Montsec, owned by the Catalan Government and operated by the Institut d'Estudis Espacials de Catalunya, Spain, using a Finger Lakes PL4240-1-BI CCD Camera (with a Class 1 Basic Broadband coated 2k x 2k chip with 13.5 microns sq. pixels). All magnitudes were obtained from a photometric solution using R magnitudes of the LGGS (Massey et al. 2006).