5.0 GHz Continuum MERLIN Observations of the Type Ia SN 2013dy
ATel #5619; M. Perez-Torres (IAA-CSIC/CEFCA, Spain), M. Argo (JBCA, Manchester), P. Lundqvist (Stockholm Observatory), G. Anderson (Soton University), R. Beswick (JBCA), C. I. Bjornsson (Stockholm Observatory), R. Fender (Oxford University), A. Rushton (Oxford/Soton), S. Ryder (AAO, Sydney), T. Staley (Oxford)
on 2 Dec 2013; 13:24 UT
Credential Certification: Miguel A. Perez-Torres (torres@iaa.es)
Subjects: Radio, Supernovae
We report MERLIN radio observations of the Type Ia supernova 2013dy,
which was discovered on 10.45 July 2013, shortly after its explosion,
in the nearby (D=13.5 Mpc) galaxy NGC 7250 (cf. CBET #3588). Our
observations were carried out during 4 - 6 August 2013, one week after
the SN reached its B-band maximum (Zheng et al. 2013). The radio
telescopes that participated in the observations included five eMERLIN
antennas (Jodrell Mk2, Pickmere, Darnhall, Knockin, and Defford). The
array observed at a central frequency of 5.090 GHz and used a total
bandwidth of 512 MHz, which resulted in a synthesized Gaussian beam of
(0.13 x 0.11) sq. arcseconds. We centered our observations at the
position of the optical discovery (RA(J2000.0)=22:18:17.60 and
DEC(J2000.0)=40:34:09.6; CBET #3588) and imaged a (20 x 20)
sq. arcsecond region centered at this position, after having stacked all our data.
We found no evidence of radio emission above a 3-sigma limit of 300
microJy/beam in a circular region of 1 arcsecond in radius, centered
at the SN position. This value corresponds to an upper limit of the
monochromatic 5.0 GHz luminosity of 6.9e25 erg/s/Hz (3-sigma), and places a
stringent upper limit to the wind mass loss rate of the supernova progenitor of
2.7e-7 solar masses per year (3-sigma), for an assumed wind speed of 10
km/s, and if the radio emission in Type Ia SNe behaves as in Type Ibc
SNe (Weiler et al. 2002).
We thank the eMERLIN staff for supporting
our ToO program in search for radio emission from Type Ia supernovae,
aimed at unveiling their progenitor scenarios.
