Discovery of an Apparent Nova in M81
ATel #6968; K. Hornoch (Astronomical Institute, Ondrejov, Czech Republic), M. Diaz Alfaro (ING, La Palma, IAC and Universidad de La Laguna, Tenerife, Spain), I. Ordonez-Etxeberria (ING, La Palma and Universidad del Pais Vasco, Bilbao, Spain), O. Vaduvescu (ING, La Palma, Spain)
on 20 Jan 2015; 19:58 UT
Credential Certification: Allen W. Shafter (aws@nova.sdsu.edu)
Subjects: Optical, Nova, Transient
Referred to by ATel #: 7019
We report the discovery of an apparent nova in M81 on a co-added 1600-s narrow-band H-alpha CCD image taken with the 2.5-m Isaac Newton Telescope (INT) + WFC at La Palma under ~2.4" seeing on 2015 Jan. 15.126 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 = 22.2. On Jan. 15.121 UT we also obtained Sloan r'-band images which helped us to classify the object. Subsequently, we found a prediscovery detection on a co-added image taken on 2014 Dec. 21.090 UT with the 0.65-m telescope at Ondrejov.
The new object designated PNV J09550693+6902588 = M81N 2015-01a (tentative designation) is located at R.A. = 9h55m06s.93, Decl. = +69o02'58".8 (equinox 2000.0), which is 140.7" west and 56.3" south of the center of M81.
The following magnitudes were obtained with the INT + WFC and the 0.65-m telescope:
2014 Nov. 26.111 UT, [22.6 (unfiltered, R-band magnitudes used from comparison stars, 0.65-m telescope); Dec. 21.090, 21.7 ± 0.3 (unfiltered, R-band magnitudes used from comparison stars, 0.65-m telescope); 2015 Jan. 15.121, Sloan r' = 22.8 ± 0.3 (INT); 15.126, H-alpha = 20.7 ± 0.15 (INT).
Strong H-alpha emission together with relative faintness in Sloan r'-band (both observed in the INT data) is consistent with classification of the object as nova.
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. We thank H. Kucakova for getting M81 images at Ondrejov on 2014 Dec. 21.090 UT.
Finding Chart
