Observations of SN2011fe with INTEGRAL

TL;DR

This paper reports INTEGRAL observations of the bright Type Ia supernova SN2011fe, providing upper limits on gamma-ray emission, constraining explosion models, and suggesting a delayed detonation of a CO white dwarf as the likely scenario.

Contribution

It presents the first INTEGRAL gamma-ray observations of SN2011fe, constrains explosion models, and supports the delayed detonation scenario over the sub-Chandrasekhar model.

Findings

INTEGRAL set upper limits on gamma-ray emission from SN2011fe.

Data favor a delayed detonation of a CO white dwarf.

Detection would be possible if the supernova occurred within 2-3 Mpc.

Abstract

SN2011fe was detected by the Palomar Transient Factory on August 24th 2011 in M101 few hours after the explosion. From the early spectra it was immediately realized that it was a Type Ia supernova thus making this event the brightest one discovered in the last twenty years. In this paper the observations performed with the instruments on board of INTEGRAL (SPI, IBIS/ISGRI, JEM-X and OMC) before and after the maximum of the optical light as well as the interpretation in terms of the existing models of $\gamma$--ray emission from such kind of supernovae are reported. All INTEGRAL high-energy have only been able to provide upper limits to the expected emission due to the decay of $^{56}$Ni. These bounds allow to reject explosions involving a massive white dwarf in the sub--Chandrasekhar scenario. On the other hand, the optical light curve obtained with the OMC camera suggests that the event was produced by a delayed detonation of a CO white dwarf that produced $\sim 0.5$ M$\odot$ of $^{56}$Ni. In this particular case, INTEGRAL would have only been able to detect the early $\gamma$--ray emission if the supernova had occurred at a distance of 2 -3 Mpc, although the brightest event could be visible up to distances larger by a factor two.