ACP Seminar (Astronomy - Cosmology - Particle Physics)

Speaker: Joseph Anderson (U. Chile)
Title: Core-collapse supernovae as tracers of massive star formation within nearby galaxies
Date (JST): Thu, Mar 22, 2012, 14:00 - 15:00
Place: Seminar Room A
Related File: 644.pdf
Abstract: Firstly we present results on constraints on core-collapse (CC) supernovae (SNe) progenitors through observations of their immdeiate environments within host galaxies. Using host galaxy H-alpha imaging we constrain differences in SN progenitor masses, finding a progenitor mass sequence starting with the type Ia SN (SNIa) arising from the lowest, through the SNII, SNIb, and the SNIc arising from the highest mass progenitors; SNIa-II-Ib-Ic. Using host HII region spectroscopy we derive environment metallicities for CC SNe and find little difference between progenitor metallicities of SNII and SNIbc. We then turn these arguments around, and using knowledge gained on the properties of CC SNe use them as tracers of star formation (SF) within nearby galaxies. We investigate the radial distribution of CC SNe within disturbed and non-disturbed host galaxies finding that within the disturbed sample the central regions of galaxies are dominated by the occurance of `stripped envelope' SNe. We argue that this cannot be explained by any metallicity bias or selection effect of very young starbursts. Therefore we conclude that we are seeing evidence of an IMF biased towards the production of high mass stars, within the central regions of interacting/disturbed galaxies. Finally we show a test case of the multiple SN population of Arp 299, where we believe we are seeing all the above processes at play within one host galaxy.