Tight constraints on the mass-loss rate of the Type Ia SN 2016coj with e-MERLIN
ATel #10168; M. Perez-Torres (IAA-CSIC), P. Lundqvist, E. Kundu (Stockholm), J. Moldon (JBCA), C.-I. Bjornsson, C. Fransson (Stockholm), S. Ryder (AAO)
on 14 Mar 2017; 12:47 UT
Credential Certification: Miguel A. Perez-Torres (email@example.com)
Subjects: Supernovae, Transient
We report e-MERLIN radio observations of the Type Ia supernova 2016coj,
which was discovered on 28.18 May 2016 (MJD 57536.18) in the nearby (D=20.1 Mpc)
galaxy NGC 4125 (cf. ATel #9095). Our observations were carried out on
3-4 June 2016 (MJD 57542.92) with a duration of 12 hr,
one week after the SN discovery and about one week before reaching its V-band maximum.
The radio telescopes that participated in the observations included five
e-MERLIN antennas (Cambridge, Pickmere, Darnhall, Knockin, and Defford). The array observed
at a central frequency of 1.51 GHz and used a total bandwidth of 512 MHz,
which resulted in a synthesized Gaussian beam of (0.13 x 0.12) sq. arcseconds.
We centered our observations at the position of the optical discovery
( (J2000.0) coordinates RA = 12:08:06.80, Dec = +65:10:37.9, ATel #9095)
and imaged a (16x16) sq. arcsecond region centered at this position.
We found no evidence of radio emission in the region surrounding SN2016coj
down to a 3-sigma limit of 126 microJy/beam, which
corresponds to an upper limit of the monochromatic 5.0 GHz luminosity of 6.1e25 erg/s/Hz (3-sigma).
Assuming the models in Kundu et al. (submitted to The Astrophysical Journal)
and Perez-Torres et al. (2014, ApJ, 792, 38) for the radio emission of Type Ia
SNe, our observations place a very stringent upper limit to the wind mass loss rate of the supernova progenitor
of 2.3e-8 solar masses per year (3-sigma) for an assumed wind speed of 100 km/s.
For typical parameters used in this model, our data are more constraining than the JVLA data in ATel #9193.
We thank the e-MERLIN staff for supporting our ToO program in search for
radio emission from Type Ia supernovae, aimed at unveiling their progenitor scenarios.