@article {2014ApJ...792...38P,
	title = {{Constraints on the Progenitor System and the Environs of SN 2014J from Deep Radio Observations}},
	journal = {The Astrophysical Journal},
	volume = {792},
	year = {2014},
	pages = {38},
	abstract = {We report deep EVN and eMERLIN observations of the Type Ia SN 2014J in the nearby galaxy M82. Our observations represent, together with JVLA observations of SNe 2011fe and 2014J, the most sensitive radio studies of Type Ia SNe ever. By combining data and a proper modeling of the radio emission, we constrain the mass-loss rate from the progenitor system of SN 2014J to $\backslash$dot$\{$M$\}$ $\backslash$lesssim 7.0$\backslash$times 10\^{}$\{$-10$\}$ $\{$$\backslash$,$\{$M\_$\{$$\backslash$odot $\}$ $\backslash$,yr\^{}$\{$-1$\}$$\}$$\}$ (for a wind speed of 100 km s$^{-1}$). If the medium around the supernova is uniform, then n $_{ISM}$ {\l}t}\~{} 1.3 cm$^{-3}$, which is the most stringent limit for the (uniform) density around a Type Ia SN. Our deep upper limits favor a double-degenerate (DD) scenario{\mdash}involving two WD stars{\mdash}for the progenitor system of SN 2014J, as such systems have less circumstellar gas than our upper limits. By contrast, most single-degenerate (SD) scenarios, i.e., the wide family of progenitor systems where a red giant, main-sequence, or sub-giant star donates mass to an exploding WD, are ruled out by our observations. (While completing our work, we noticed that a paper by Margutti et al. was submitted to The Astrophysical Journal. From a non-detection of X-ray emission from SN 2014J, the authors obtain limits of $\backslash$dot$\{$M$\}$ $\backslash$lesssim 1.2 $\backslash$times 10\^{}$\{$-9$\}$ M $_{\&sun;}$ yr$^{-1}$ (for a wind speed of 100 km s$^{-1}$) and n $_{ISM}$ {\l}t}\~{} 3.5 cm$^{-3}$, for the {$\rho$}vpropr $^{-2}$ wind and constant density cases, respectively. As these limits are less constraining than ours, the findings by Margutti et al. do not alter our conclusions. The X-ray results are, however, important to rule out free-free and synchrotron self-absorption as a reason for the radio non-detections.) Our estimates on the limits on the gas density surrounding SN2011fe, using the flux density limits from Chomiuk et al., agree well with their results. Although we discuss the possibilities of an SD scenario passing observational tests, as well as uncertainties in the modeling of the radio emission, the evidence from SNe 2011fe and 2014J points in the direction of a DD scenario for both.},
	keywords = {stars: mass-loss, supernovae: individual: SN2011fe SN2014J},
	doi = {10.1088/0004-637X/792/1/38},
	url = {http://adsabs.harvard.edu/abs/2014ApJ...792...38P},
	author = {M. A. P{\'e}rez-Torres and Lundqvist, P. and Beswick, R.~J. and Bj{\"o}rnsson, C.~I. and Muxlow, T.~W.~B. and Paragi, Z. and Ryder, S. and Alberdi, A. and Fransson, C. and Marcaide, J.~M. and Mart{\'\i}-Vidal, I. and Ros, E. and Argo, M.~K. and Guirado, J.~C.}
}
@article {2011MNRAS.415.2688R,
	title = {{The core-collapse supernova rate in Arp 299 revisited}},
	journal = {Monthly Notices of the Royal Astronomical Society},
	volume = {415},
	year = {2011},
	pages = {2688-2698},
	abstract = {We present a study of the core-collapse supernova (CCSN) rate in nuclei A and B1, of the luminous infrared galaxy (LIRG) Arp 299, based on {\tilde}11 yr of Very Large Array (VLA) monitoring of their radio emission at 8.4 GHz. Significant variations in the nuclear radio flux density can be used to identify the CCSN activity in the absence of high-resolution very long baseline interferometry (VLBI) observations. In the case of the B1-nucleus, the small variations in its measured diffuse (synchrotron plus free-free) radio emission are below the fluxes expected from radio supernovae (RSNe), thus making it well-suited to detect RSNe through flux density variability. In fact, we find strong evidence for at least three RSNe this way, which results in a lower limit for the CCSN rate ({$ν$}$_{SN}$) of {\gt}0.28$^{+0.27}$$_{-0.15}$ yr$^{-1}$. This value agrees within the uncertainties with the infrared (IR) luminosity based SN rate estimate, and with previously reported radio estimates. In the A-nucleus, we did not detect any significant variability and found a SN detection threshold luminosity of {\ap}3.1 {\times} 10$^{28}$ erg s$^{-1}$ Hz$^{-1}$, allowing only the detection of the most luminous RSNe known. Our method is basically blind to normal CCSN explosions occurring within the A-nucleus, which result in too small variations in the nuclear flux density, remaining diluted by the strong diffuse emission of the nucleus itself. Additionally, we have attempted to find near-IR (NIR) counterparts for the earlier reported RSNe in the Arp 299 nucleus A, by comparing NIR adaptive optics images from the Gemini-N Telescope with contemporaneous observations from the European VLBI Network (EVN). However, we were not able to detect NIR counterparts for the reported radio SNe within the innermost regions of nucleus A. While our NIR observations were sensitive to typical CCSNe at {\tilde}300 mas (or 70 pc projected distance) from the centre of the nucleus A, suffering from extinction up to A$_{V}${\tilde} 15 mag, they were not sensitive to such highly obscured SNe within the innermost nuclear regions where most of the EVN sources were detected.},
	keywords = {galaxies: individual: NGC 3690:IC 694, galaxies: starburst, supernovae: general},
	doi = {10.1111/j.1365-2966.2011.18886.x},
	url = {http://adsabs.harvard.edu/abs/2011MNRAS.415.2688R},
	author = {Romero-Ca{\~n}izales, C. and Mattila, S. and Alberdi, A. and M. A. P{\'e}rez-Torres and Kankare, E. and Ryder, S.~D.}
}
