Radio Detection and X-ray Limits for Nova Cep 2013
ATel #4950; L. Chomiuk (MSU/NRAO), T. Nelson (Minnesota), M. Rupen (NRAO), K. Mukai (UMBC/GSFC), J. Sokoloski, J. Weston, Y. Zheng (Columbia), A. Mioduszewski (NRAO), U. Munari (INAF Asiago
on 4 Apr 2013; 17:36 UT
Credential Certification: Laura Chomiuk (chomiuk@pa.msu.edu)
Subjects: Radio, Ultra-Violet, X-ray, Nova
We report radio continuum observations from the Karl G. Jansky Very Large Array (VLA) and X-ray observations from Swift for Nova Cep 2013 (discovered on 2013 Feb 2.4; CBET #3397). Nova Cep 2013 had an expansion velocity of 1,200 km/s and optical decline time of t_2 = 12 days (CBET #3397; ATel #4893); its optical light curve faded dramatically on March 13, perhaps signifying dust formation (ATel #4893).
We have acquired two epochs of VLA observations to date. The first, on 2013 Feb 14.0 UT, yielded non-detections: 8 +/- 10 microJy at 7.4 GHz and -51 +/- 39 microJy at 36.5 GHz. The nova was detected in our second epoch, on 2013 Mar 22.5, with flux densities: 189 +/- 20 microJy at 7.4 GHz and 718 +/- 51 microJy at 36.5 GHz.
We also obtained two observations of Nova Cep 2013 with the XRT and UVOT instruments onboard the Swift satellite. The first Swift observation was carried out on 2013 Feb 8.3 (5.9 days after discovery.) The total XRT exposure time was 3688 s. The source was not formally detected, although 2 photons were present within a 10 pixel radius circle centered on the source position. The resulting 99% confidence level upper-limit on the 0.3-10.0 keV count rate, determined using the Bayesian method of Kraft, Burrows and Nousek (1991) is 3.2 e-3 cts/s. A faint UV source is detected at the position of the nova in the 2629 s UVOT exposure, with a magnitude in the UVM2 filter (central wavelength = 2246 Angstroms) of 19.96 +/- 0.14 (stat) +/- 0.03 (sys).
The second Swift observation was obtained on 2013 Feb 22.1 (19.7 days after discovery.) Nova Cep was not detected in the 5809 s XRT exposure, with a 99% confidence level upper limit on the 0.3-10 keV count rate of 8.0e-4 cts/s. The UVM2 magnitude measured during the 5727 s UVOT exposure was 19.54 +/- 0.08 (stat) +/- 0.03 (sys), about 0.4 mags brighter than in the first observation.
Radio observations are ongoing, and we encourage observations at other wavelengths.
Kraft, R. P., Burrows, D. N. & Nousek, J. A., 1991, ApJ 374, 334
E-Nova Project