EXTREME TYPE IIP SUPERNOVAE AS YARDSTICKS FOR COSMOLOGY

摘要

Evolutionary effects with redshift of core collapse supernovae and their appli-cation to cosmology have been studied based on an extensive grid of stellar modelsbetween 13 and 25 M_N,and their light curves after the explosion. With decreasing metallicity Z, and increasing mass, progenitors tend to ex-plode as compact Blue Supergiants (BSG) and produce subluminous supernovaewhich are about 1.5~m dimmer compared to 'normal' SNeII with Red Supergiant(RSG) progenitors. Progenitors with small masses tend to explode as RSGs evenwith low Z. The consequences are obvious for probing the chemical evolution. We identify extreme SNe Hp supernovae as a rather homogeneous class whichmay allow their use as standard candles for distance determination accurate within30%. Due to their unique light curves, no spectra need to be taken for their identi-fication, and follow-up observations can be limited to a very small dynamical rangein brightness. This means that distance determination by 'extreme SNe IIp' arepossible up to redshifts of O3 using 8-meter class telescopes. SIRTIF may pushthe limit by another magnitude.