Discovery of Two Probable Novae in M81
ATel #4462; K. Hornoch (Astronomical Institute, Ondrejov, Czech Republic), L. Patrick (ING, La Palma, Spain & University of Sheffield, UK), D. Arnold, L. Dominguez, A. Gonzalez Fernandez, L. Hardy, M. Hrudkova, P. van Oers, Y. Ramanjooloo, R. Karjalainen (ING, La Palma, Spain), O. Vaduvescu (ING, La Palma & IAC, Tenerife, Spain)
on 8 Oct 2012; 01:29 UT
Credential Certification: Allen W. Shafter (aws@nova.sdsu.edu)
Subjects: Optical, Nova, Transient
We report the discovery of two probable novae in the M81 galaxy 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 on Sep. 28.233 UT. The new objects are well visible on the co-added image (see the finding chart linked below) and faintly visible on individual 400-s frames, but are not present on numerous narrow-band H-alpha archival images from the INT down to limiting magnitude as faint as H-alpha = 22.3.
We also obtained Sloan r'-band images that helped us to classify the objects. Strong H-alpha emission together with relative faintness in the Sloan r' band supports the classification of the objects as novae.
Designations, positions, and offsets of the new objects from the center of M81 are summarized in the following table:
TOCP designation CBAT designation R.A. (J2000) Dec. (J2000) Offset R.A. Offset Dec.
PNV J09551009+6903254 M81N 2012-09a? 09 55 10.09 +69 03 25.4 123.7" W 29.7" S
PNV J09553556+6904271 M81N 2012-09b? 09 55 35.56 +69 04 27.1 12.8" E 32.0" N
The photometry obtained with the INT + WFC is summarized here:
PNV J09551009+6903254 PNV J09553556+6904271
Date UT H-alpha mag Sloan r' mag H-alpha mag Sloan r' mag
2012 05 22.901 > 22.0 > 21.9
2012 05 22.919 > 22.5 > 22.4
2012 09 28.233 19.0 +/- 0.15 20.1 +/- 0.3
2012 09 29.233 18.9 +/- 0.1 20.0 +/- 0.15
2012 09 29.249 20.8 +/- 0.3 > 21.2
2012 09 30.241 19.0 +/- 0.1 20.0 +/- 0.2
2012 09 30.254 20.9 +/- 0.25 > 21.3
2012 10 02.230 19.1 +/- 0.15 20.2 +/- 0.3
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.
Finding chart