The carbon-rich type Ic SN 2007gr: the photospheric phase

TL;DR

This paper presents early spectroscopic and photometric observations of the nearby type Ic supernova SN 2007gr, revealing unique spectral features and velocity profiles that contribute to understanding the diversity of core-collapse supernovae.

Contribution

It provides detailed early-phase data on SN 2007gr, highlighting unusual spectral line widths and prominent carbon features, advancing knowledge of supernova composition and behavior.

Findings

SN 2007gr has narrow spectral lines and flat velocity profile.

Detection of prominent carbon features indicates variable carbon abundance.

SN 2007gr may help explain diversity in core-collapse supernovae.

Abstract

The first two months of spectroscopic and photometric monitoring of the nearby type Ic SN 2007gr are presented. The very early discovery (less than 5 days after the explosion) and the relatively short distance of the host galaxy motivated an extensive observational campaign. SN 2007gr shows an average peak luminosity but unusually narrow spectral lines and an almost flat photospheric velocity profile. The detection of prominent carbon features in the spectra is shown and suggest a wide range in carbon abundance in stripped-envelope supernovae. SN 2007gr may be an important piece in the puzzle of the observed diversity of CC SNe.