Title: No X-rays from the very nearby Type Ia SN2014J: constraints on its environment Author: R. Margutti, J. Parrent, A. Kamble, A.M. Soderberg, R.J. Foley, D. Milisavljevic, M.R. Drout, R. Kirshner
Deep X-ray observations of the post-explosion environment around the very nearby Type Ia SN\,2014J (Dl=3.5 Mpc) reveal no X-ray emission down to a luminosity L<7x10^{36} erg/s (0.3-10 keV) at t~20 days after the explosion. We interpret this limit in the context of Inverse Compton emission from upscattered optical photons by the supernova shock and constrain the pre-explosion mass-loss rate of the stellar progenitor system to be <10^{-9} M_sun yr-1 (for wind velocity v_w=100 km/s). Alternatively, the SN shock might be expanding into a uniform medium with density n_CSM<3 cm-3. These results rule out single-degenerate (SD) systems with steady mass-loss until the terminal explosion and constrain the fraction of transferred material lost at the outer Lagrangian point to be <1%. The allowed progenitors are (i) WD-WD progenitors, (ii) SD systems with unstable hydrogen burning experiencing recurrent nova eruptions with recurrence time t<300 yrs and (iii) stars where the mass loss ceases before the explosion.
Title: The peculiar extinction law of SN2014J measured with The Hubble Space Telescope Author: R. Amanullah, A. Goobar, J. Johansson, D. P. K. Banerjee, V. Venkataraman, V. Joshi, N. M. Ashok, Y. Cao, M. M. Kasliwal, S. R. Kulkarni, P. E. Nugent, T. Petrushevska, V. Stanishev
The wavelength-dependence of the extinction of Type Ia SN2014J in the nearby galaxy M82 has been measured using UV to near-IR photometry obtained with the Hubble Space Telescope, the Nordic Optical Telescope, and the Mount Abu Infrared Telescope. This is the first time that the reddening of a SN Ia is characterized over the full wavelength range of 0.2-2 microns. A total-to-selective extinction, R_V\geq3.1, is ruled out with high significance. The best fit at maximum using a Galactic type extinction law yields RV=1.4±0.1. The observed reddening of SN2014J is also compatible with a power-law extinction, A_{\lambda}/A_V = \left( {\lambda}/ {\lambda_V} ight)^{p} as expected from multiple scattering of light, with p=-2.1±0.1. After correction for differences in reddening, SN2014J appears to be very similar to SN2011fe over the 14 broad-band filter light curves used in our study.
Title: Supernova 2014J at maximum light Author: D.Yu.Tsvetkov, V.G. Metlov, S.Yu. Shugarov, T.N. Tarasova, N.N. Pavlyuk
We present UBVRI photometry of the supernova 2014J in M82, obtained in the period from January 24 until March 3, 2014, as well as two spectra, taken on February 4 and March 5. We derive dates and magnitudes of maximum light in the UBVRI bands, the light curve parameters Delta m(15) and expansion velocities of the prominent absorption lines. We discuss colour evolution, extinction and maximum luminosity of SN 2014J.