Discovery of Two Novae in M81
ATel #4129; K. Hornoch (Astronomical Institute, Ondrejov, Czech Republic), O. Vaduvescu (ING & IAC, La Palma, Spain), C. Zurita (IAC, La Palma, Spain), L. Patrick (ING, La Palma, Spain & University of Sheffield, UK), H. Ledo (ING, La Palma, Spain & CAR, U. of Hertfordshire, UK), R. Karjalainen (ING, La Palma, Spain)
on 25 May 2012; 23:57 UT
Credential Certification: Allen W. Shafter (firstname.lastname@example.org)
Subjects: Optical, Nova, Transient
We report the discovery of two novae 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 ~0.8" seeing on May 22.901 UT.
The new objects are well visible on the co-added image (see the finding chart linked below) as well as 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 obtained also Sloan r' and Sloan i'-band images which helped us to classify
the objects. Strong H-alpha emission together with relative faintness in
Sloan r' and Sloan i' bands supports the classification of the objects as novae.
Significantly stronger H-alpha emission of PNV J09552271+6903162 when compared to
PNV J09553273+6902173 agrees with the different stages of the outburst in each
of the objects.
Designations, positions, and offsets of the new objects from the M81 center are
summarized in the following table:
TOCP designation CBAT designation R.A. (J2000) Dec. (J2000) Offset R.A. Offset Dec.
PNV J09552271+6903162 M81N 2012-05a? 09 55 22.71 +69 03 16.2 56.1" W 38.9" S
PNV J09553273+6902173 M81N 2012-05b? 09 55 32.73 +69 02 17.3 2.4" W 97.8" S
The photometry obtained with the INT + WFC is summarized here:
PNV J09552271+6903162 PNV J09553273+6902173
Date UT H-alpha mag Sloan r' mag H-alpha mag Sloan r' mag
2012 04 29.000 > 21.2 > 21.2
2012 05 16.944 19.5 +/- 0.2 > 20.2
2012 05 22.901 19.56 +/- 0.10 19.66 +/- 0.10
2012 05 22.919 21.6 +/- 0.15 20.60 +/- 0.08
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.