Discovery of Eleven Optical Nova Candidates in M81
ATel #3871; K. Hornoch (Astronomical Institute, Ondrejov, Czech Republic) and B. Sipocz (Centre for Astrophysics Research, U. of Hertfordshire, UK)
on 20 Jan 2012; 17:36 UT
Credential Certification: Allen W. Shafter (aws@nova.sdsu.edu)
Subjects: Optical, Nova, Transient
Referred to by ATel #: 3888
We report the discovery of five nova candidates in M81 found on a co-added 1100-s
narrow-band H-alpha CCD image taken on 2012 Jan. 9.102 UT with the 2.54-m Isaac
Newton Telescope (INT) at La Palma.
The new objects are visible on the single frames used for the co-added image, 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.
Designations, positions, offsets from the galaxy center, and narrow-band H-alpha
magnitudes are summarized in the following table:
| TOCP designation | CBAT designation | R.A. | Decl. |
Offset R.A. | Offset Decl. | H-alpha mag |
|---|
| PNV J09553278+6902139 | 2012-01a? |
09 55 32.78 | +69 02 13.9 | 2.1" W |
101.2" S | 19.31 +/- 0.05 |
| PNV J09555380+6903383 | 2012-01b? |
09 55 53.80 | +69 03 38.3 | 110.6" E |
16.8" S | 19.26 +/- 0.05 |
| PNV J09555778+6902041 | 2012-01c? |
09 55 57.78 | +69 02 04.1 | 132.0" E |
111.0" S | 20.50 +/- 0.09 |
| PNV J09553792+6902498 | 2012-01d? |
09 55 37.92 | +69 02 49.8 | 25.5" E |
65.3" S | 20.49 +/- 0.09 |
| PNV J09553560+6904154 | 2012-01e? |
09 55 35.60 | +69 04 15.4 | 13.0" E |
20.3" N | 20.10 +/- 0.10 |
As comparison, we newly used images from the ING data archive which were taken with the INT
on 2009 May 5.000 UT. Using six individual frames with exposure time of 600-s each,
we got a deep, high-quality co-added image. By thorough visual comparison of this archival image
and our recent image from Jan. 9.102 UT, we find six new nova candidates on the archival image.
None of those have any records in any searches of papers or WWW pages devoted to extragalactic
novae neither on SIMBAD. The new objects are visible on single frames used for the co-added image,
but none of them is present on any other archival H-alpha INT image down to limiting magnitude
as faint as H-alpha = 22.3.
In addition, we measured following magnitude of the PNV J09553266+6906072 (ATEL #3735),
a bright nova in M81 (ATEL #3770): 2012 Jan. 9.102 UT, H-alpha = 19.41 +/- 0.05.
Supplementary material containing table with their designations, positions, offsets from the galaxy
center, and narrow-band H-alpha magnitudes as well as their identification chart and a finding chart
of the five M81 nova candidates from 2012 Jan. 9.102 UT is available through the link below.
Supplemental Material
