2016MNRAS.459..595Y

We present late time, low-frequency observations of SN 2011dh made using the Giant Metrewave Radio Telescope (GMRT). Our observations at 325, 610 and 1280 MHz conducted between 93 and 421 d after the explosion supplement the millimeter and centimetre wave observations conducted between 4 and 15 d after explosion using the Combined Array for Research in Millimeter-wave Astronomy (CARMA) and extensive radio observations (1.0-36.5 GHz) conducted between 16 and 93 d after explosion using Jansky Very Large Array (JVLA). We fit a synchrotron self absorption model (SSA) to the 610 and 1280 MHz radio light curves. We use it to determine the radius (R_p) and magnetic field (B_p) at 173 and 323 d after the explosion. A comparison of the peak radio luminosity L_op with the product of the peak frequency ν_p and time to peak t_p shows that the supernova evolves between the epochs of CARMA, JVLA and GMRT observations. It shows a general slowing down of the expansion speed of the radio emitting region on a time-scale of several hundred days during which the shock is propagating through a circumstellar medium set up by a wind with a constant mass-loss parameter, . We derive the mass-loss parameter (A_*) based on 610 and 1280 MHz radio light curves, which are found to be consistent with each other within error limits.