Radio Non-Detection of ASASSN-15lh = SN2015L
ATel #8388; E. C. Kool (Macquarie University/AAO), S. D. Ryder (AAO), C. J. Stockdale (Marquette), C. Romero-Canizales (PUC, MAS), J. L. Prieto (Diego Portales; MAS), R. Kotak (QUB)
on 9 Dec 2015; 00:53 UT
Credential Certification: Stuart Ryder (firstname.lastname@example.org)
Subjects: Radio, Supernovae, Transient
ASASSN-15lh (=SN 2015L; CBET #4120) appears to be the most luminous SN yet found (ATel #7642, #7774; Dong et al. 2015, arXiv:1507.03010). We observed SN 2015L with the Australia Telescope Compact Array (ATCA) at 5.5 and 9 GHz, on 2015 November 21.1 UT.
No radio emission was detected at the supernova location, to a 3-sigma upper limit of 23 microJy at 5.5 GHz and 21 microJy at 9 GHz. Based on a luminosity distance of 1171 Mpc (Dong et al. 2015) these correspond to luminosity upper limits of 3.8E28 and 3.4E28 erg/s/Hz, respectively. Only the most luminous Type Ibc and Type IIn objects exceed this threshold at a similar stage of their evolution (Perez-Torres et al. 2014, http://adsabs.harvard.edu/abs/2015aska.confE..60P ). These results are in
keeping with Milisavljevic et al. (ATel #8216) finding no clear evidence from optical spectroscopy of interaction with an H-rich circumstellar environment.
We would like to extend our thanks to the ATCA staff for enabling these observations. The Australia Telescope Compact Array is part of the Australia Telescope which is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO.