Open AccessThe type IIn supernova 1995G: interaction with the circumstellar medium
Author(s) -
Pastorello A.,
Turatto M.,
Benetti S.,
Cappellaro E.,
Danziger I. J.,
Mazzali P. A.,
Patat F.,
Filippenko A. V.,
Schlegel D. J.,
Matheson T.
Publication year - 2002
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2002.05366.x
Subject(s) - physics , ejecta , supernova , astrophysics , balmer series , luminosity , spectral line , light curve , emission spectrum , astronomy , galaxy
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 700 km s −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 n H ≫10 8 cm ‐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.