Discovery of Two Apparent Novae in M81 and H-alpha Confirmation of PNV J09554276+6904230
ATel #5918; K. Hornoch (Astronomical Institute, Ondrejov, Czech Republic), V. Tudor, O. Vaduvescu, (ING, La Palma, Spain)
on 25 Feb 2014; 00:06 UT
Credential Certification: Allen W. Shafter (aws@nova.sdsu.edu)
Subjects: Optical, Nova, Transient
We report the discovery of two apparent 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 ~1.3" seeing on 2014 Feb. 21.018 UT.
The new objects are well visible on the co-added image (see the finding charts
linked below), 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.
On Feb. 21.016 UT we obtained also Sloan r'-band images which helped us to classify
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 J09553112+6906154 M81N 2014-02b? 09 55 31.12 +69 06 15.4 11.0" W 140.3" N
PNV J09553488+6910194 M81N 2014-02c? 09 55 34.88 +69 10 19.4 9.1" E 384.3" N
The photometry obtained with the INT + WFC for the two new objects and for the M81 nova
candidate PNV J09554276+6904230 discovered by C. Hergenrother and announced
here
is summarized in the next table:
2014 02 21.016 2014 02 21.018
Object Sloan r' mag H-alpha mag
PNV J09553112+6906154 21.6 +/- 0.15 19.6 +/- 0.1
PNV J09553488+6910194 19.93 +/- 0.04 20.03 +/- 0.07
PNV J09554276+6904230 21.00 +/- 0.09 19.8 +/- 0.15
The similarity in brightness of the PNV J09553488+6910194 in narrow-band H-alpha
and Sloan r'-band together with a non-detection of the object down to a limiting
magnitude I = 21.9 on Feb. 14.038 UT (on image obtained by S. Perez and J. Gorosabel
using the 1.23-m telescope at Calar Alto), is consistent with a very young nova
discovered shortly after eruption. For this object, we also obtained a follow-up
unfiltered magnitude (using R-band magnitudes from comparison stars) of 19.7 ± 0.15
with the 0.65-m telescope at Ondrejov on Feb. 22.785 UT.
After the discovery of the PNV J09553112+6906154, we found prediscovery detections
on unfiltered images taken with the 0.65-m telescope at Ondrejov and on the I-band
image from the 1.23-m telescope at Calar Alto. We obtained following magnitudes
(unfiltered using R-band magnitudes from comparison stars, unless otherwise noted):
2014 Jan. 4.082 UT, H-alpha > 22.0 (2.5-m INT); 16.027, 21.1 ± 0.3 (0.65-m);
Feb. 4.139, 21.7 ± 0.3 (0.65-m); 10.210, 21.7 ± 0.3 (0.65-m); 14.038,
I = 20.9 ± 0.25 (1.23-m).
Strong H-alpha emission together with relative faintness in Sloan r'-band (both observed
in the INT data) supports the classification of the PNV J09553112+6906154 as nova.
Relatively strong H-alpha emission observed in the INT data for the PNV J09554276+6904230
also supports its classification 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 S. Perez and J. Gorosabel for getting M81 images at Calar Alto
and H. Kucakova and J. Vrastil at Ondrejov.
Finding chart for the PNV J09553112+6906154
Finding chart for the PNV J09553488+6910194
