The Stellar Population Analysis Of Supernova Host Galaxies

The explosion of supernova is one of the most drastic astronomical phenomenon inuniverse. It is the termination of some kinds of massive stars, releasing enormous materialsand tremendous energy. According to the H line in its spectrum, it can be devided into twocatalogs: SN II and SN I. Then SN I without H line can be separated into Ia, Ib and Ic. Thehost galaxy of SN play an important role in the evolution and explosion of SN. There havebeen many researches about the type of SN in host galaxies with different ages andmetallicity.Prantzos&Boissier (2003) and Boissier&Prantzos (2009) found that the ratio ofnumbers of SN Ibc and SN II increased with the increasing metallicity.Preito et al.(2008)found the host galaxies of SN Ibc had higher metallicity than SN Ia and SN II, using the directmeasurement of metallicity of the whole host galaxies. Hammuy et al.(1996) found the fainterSN Ia exploded in the early-type galaxies, while the brighter ones exploded in the late-typegalaxies. Gallagher et al.(2008) reckoned that the peak-magnitude of SN in old galaxies wasabout one magnitude fainter than those in young galaxies, namely the faint SN Ia exploded inold galaxies. Sullivan et al.(2006)&Aubourg et al.(2008) found the evidence of short-lifeprogenitor of SN Ia in their host galaxies, constricting the mass-range of SN Ia. Theseresearchers made enormous strides in this area, but the samples they used are small. They didnot compare the stellar-population with different types of SN host galaxies, althoughstellar-population is a very good parameter in describing the SN exploding environment. Sowe matched the SDSS main-galaxy catalog and Asiago supernova catalogue and studied thestellar-population of different types of SN host galaxies.We matched SDSS and Asiago Catalogue with30arcsecond and got1201samples. Forthe ones whose light-fraction were bigger than0.15, we checked their images and spectrumand finally got234samples. The we separated this sample into137emission-line galaxies and97absorbtion-line galaxies. We used STARLIGHT fitting the continuous spectrum and absorbtion lines of oursamples, getting the stellar-population of different ages and metallicities of their host galaxies.We also got other parameters, such as Dn (4000)，H A，stellar mass and SFR, from MPA/JHU.From the fitting results, we found that:For emission-line galaxies,1) the contribution of young stellar population of SN II hostgalaxies is the largest, suggesting they are younger than both SN Ia host galaxies and SN Ib/chost galaxies.2) The contribution of metal-rich stellar population of SN II host galaxies is theleast and that of SN Ib/c host galaxies is the largest, which may be a proof that SN Ib/c isprone to explode in more metal-rich evironments than SN II.3) The age of young stellarpopulation of host galaxies calculating from Hαand Hβemission-line give us the low limitof age of supernova host galaxies.4) SN Ia is prone to explode in massive galaxies, while SNII is prone to explode in both massive galaxies and dwalf galaxies.For absorption-line galaxies,1) the contribution of young stellar population of SN Ia hostgalaxies is the least, suggesting they are older than both SN II host galaxies and SN Ib/c hostgalaxies.2) The contribution of metal-rich stellar population of SN Ia host galaxies is thelargest, which may suggest that SN Ia is prone to explode in metal-rich evironments.Compared the emission-line galaxies and the absorption-line galaxies,1) for the samekind of supernova, the emission-line host galaxies are younger and more metal-poor than theabsorption-line ones.2) The stellar mass of absorption-line host galaxies is relative larger andthe SFR is lower than emission-line ones.