eMERLIN radio detection of SN2013df at 5.0 GHz
ATel #8452; M. Perez-Torres (IAA-CSIC, Spain), M. Argo (JBCA, Manchester), I. MartÃ-Vidal (OSO, Sweden), A. Alberdi (IAA-CSIC, Spain), R. Herrero-Illana (IAA-CSIC), R. Beswick (JBCA, Manchester), E. Ros (MPIfR, Bonn), J. Marcaide (Univ. Valencia, Spain), J. C. Guirado (Univ. Valencia, Spain), T. Muxlow (JBCA, Manchester), C. Stockdale (Marquette Univ., USA), V. Tudose (ISS, Bucharest), Z. Paragi (JIVE, Dwingeloo)
on 23 Dec 2015; 08:18 UT
Credential Certification: Miguel A. Perez-Torres (firstname.lastname@example.org)
Subjects: Radio, Supernovae
We report the first radio detection of the type IIb SN 2013df at 5.0 GHz, using the electronic Multi-Element Radio Linked Interferometer Network (eMERLIN). SN 2013df was discovered on 7.9 June 2013 (Ciabattari et al. CBET #3557) in the nearby (D=13.6 Mpc) galaxy NGC 4414, and was detected early at X-rays (Li et al. ATel #5150). SN2013df was expected to have significant radio emission, based on its level of X-ray emission, alike the cases of the Type IIb supernovae SN1993J, SN 2001gd, or the more recent SN 2011dh, and recently Kamble et al. (2015, arXiv) presented multi-wavelength VLA observations of SN2013df, which confirm SN2013df as a 93J-like object.
We observed SN 2013df at a frequency of 5.07 GHz on 2013 July 23 with eMERLIN, using a total bandwidth of 512 MHz. The resulting synthesized Gaussian beam was of (54 x 35) sq. milliarcseconds. We centered our observations at the position of the X-ray discovery (RA(J2000.0)=12:26:29.52 and DEC(J2000.0)=31:13:37.5 with an uncertainty of 3.8 arcsec) and imaged a large, 30x30 sq. arcsecond region around that position. We clearly detected SN 2013df for the first time at 5 GHz, with a peak flux density of 1.352 mJy/b at the following position: RA(J2000.0)=12:26:29.3410; DEC(J2000.0)=31:13:38.134 (the estimated uncertainty is 5 mas in each coordinate). The off-source r.m.s. of the image was of 0.068 mJy/b. The above radio brightness corresponds to a monochromatic 5.07 GHz luminosity of (3.0 +/- 0.3)*1e26 erg/s/Hz at an age of the SN of about 49 days. At this same age, SN1993J showed a 4.9 GHz flux density of (3.5 +/- 0.1)*1e26 erg/s/Hz, and was still in its optically thick phase, as has been the case for SN2013df, which also confirms their expected similarities.
We thank the eMERLIN staff for supporting our observations.