Early-type host galaxies of type II and Ib supernovae

Abstract

Recent studies find that some early-type galaxies host Type II or Ibc supernovae (SNeII, Ibc). This may imply recent star formation activities in these SNehost galaxies, but a massive star origin of the SNeIb so far observed in early-type galaxies has been questioned because of their intrinsic faintness and unusually strong Ca lines shown in the nebular phase. To address the issue, we investigate the properties of early-type SNe host galaxies using the data with Galaxy Evolution Explorer (GALEX) ultraviolet photometry and the Sloan Digital Sky Survey optical data. Our sample includes eight SNeII and one peculiar SNIb (SN2000ds) host galaxies as well as 32 SNIa host galaxies. The host galaxy of SN2005cz, another peculiar SNIb, is also analyzed using the GALEX data and the NASA/IPAC Extragalactic Database optical data. We find that the NUV-optical colors of SNII/Ib host galaxies are systematically bluer than those of SNIa host galaxies, and some SNII/Ib host galaxies with NUV - r colors markedly bluer than the others exhibit strong radio emission. We perform a stellar population synthesis analysis and find a clear signature of recent star formation activities in most of the SNII/Ib host galaxies. Our results generally support the association of the SNeII/Ib hosted in early-type galaxies with core collapse of massive stars. We briefly discuss implications for the progenitors of the peculiar SNeIb 2000ds and 2005cz. © 2011. The American Astronomical Society. All rights reserved.