The type IIn supernova 1995G: interaction with the circumstellar medium
Abstract
We present the photometric and spectroscopic evolution of the type IIn SN 1995G in NGC 1643, on the basis of 4 years of optical and infrared observations. This supernova shows very flat optical light curves similar to SN 1988Z, with a slow decline rate at all times. The spectra are characterized by strong Balmer lines with multiple components in emission and with a P Cygni absorption component blueshifted by only 700kms-1. This feature indicates the presence of a slowly expanding shell above the SN ejecta as in the case of SNe 1994aj and 1996L. As in other SNe IIn, the slow luminosity decline cannot be explained only with a radioactive energy input, and an additional source of energy is required, most likely that produced by the interaction between supernova ejecta and a pre-existent circumstellar medium (CSM). It was estimated that the shell material has a density nH>>108cm-3, consistent with the absence of forbidden lines in the spectra. About 2 years after the burst the low-velocity shell is largely overtaken by the SN ejecta and the luminosity drops at a faster rate.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- June 2002
- DOI:
- 10.1046/j.1365-8711.2002.05366.x
- arXiv:
- arXiv:astro-ph/0201483
- Bibcode:
- 2002MNRAS.333...27P
- Keywords:
-
- circumstellar matter;
- supernovae: general;
- supernovae: individual: SN 1995G;
- supernovae: individual: SN 1988Z;
- galaxies: individual: NGC 1643;
- Astrophysics
- E-Print:
- 14 pages, including 11 figures. Accepted by MNRAS