X-ray and UV observations of Nova Mon 2012

ATel #4321; Thomas Nelson (Minnesota), Koji Mukai (UMBC and NASA/GSFC), Laura Chomiuk (Michigan State/NRAO), Jennifer Sokoloski (Columbia), Jennifer Weston (Columbia), Michael Rupen (NRAO), Amy Mioduszewski (NRAO), Nirupam Roy (NRAO)
on 20 Aug 2012; 21:47 UT
Credential Certification: Thomas Nelson (tnelson@physics.umn.edu)

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Recently, Cheung et al. (ATel #4310) suggested that the transient gamma-ray source discovered with the Fermi Large Area Telescope (LAT) on 2012 June 22 (Fermi J0639+0548, ATel #4224) was associated with Nova Mon 2012 (PNV J06393874+0553520), which was discovered in the optical on 2012 Aug 9 (CBET #3202). Nova Mon 2012 (see also ATel #4320) is the third nova to be associated with a transient LAT source.

The Swift/XRT observed Nova Mon for 5733 s on 2012 August 19, 10 days after the optical discovery and 58 days after the LAT transient detection, and detected a strong hard X-ray source. Extracting source events from a 30 pixel radius circle centered on the position of the nova, we found a 0.3-10 keV background-subtracted count rate of 0.14 c/s. The X-ray spectrum was hard and highly absorbed, with the majority of counts having energies above 2 keV. Modeling the spectrum as an absorbed thermal plasma with the APEC model in XSpec, we find a best fit N(H) of (3.1 +/- 0.4) x 10^22 cm^-2, and a plasma temperature of 4.0 (+1.4,-0.8) x 10^7 K (kT = 3.2 (-0.5,+0.8) keV). The 0.3-10 keV flux was 1.11 (+0.06,-0.12) x 10^-11 erg/s/cm^2.

The UVOT instrument also obtained ultraviolet images in the UVM2 band, with a total exposure time of 5703 s. The nova was detected with an average UVM2 magnitude of 11.52 +/- 0.08.

These observations were obtained as part of the E-Nova project, an effort to obtain high quality radio light curves and complimentary multiwavelength observations of novae visible to the Karl G. Jansky Very Large Array. Further observations of this nova with Swift are planned.

E-Nova Project Website