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The Subaru Seminar is usually held in Room 104 of the Hilo Base Facility, adjacent to the main lobby. Everyone is welcome to attend. If you are interested in giving a seminar, please contact Subaru seminar organizers (Tomonori Usuda, Kumiko S. Usuda, Masayuki Akiyama) by email : (please change"_at" to @).

April 25, Tuesday at 11:00am

" Multi-band light curve studies of SNe Ia "

Naohiro Takanashi

(University of Tokyo)

SNe Ia are very important for the cosmological studies, but they are not perfect "standard candle". They have considerable intrinsic dispersion in their light curves (c.f. Phillips et al.1993). In addition, host galaxy dust extinction and peculiarity of SNe Ia give uncertainty in apparent brightness. Recently, we can use many samples of nearby SNe Ia to find out how we should reduce the intrinsic dispersion and how we should make corrections of uncertainty (c.f. Takanashi, 2005, master thesis; Takanashi et al., 2006, in prep.; Altavilla et al., 2004; Reindl et al., 2005). It is also interesting why SNe Ia have intrinsic dispersion and why there are peculiar ones. Some ideas are proposed for the cause of dispersion (e.g. Umeda et al., 1999), but the question is still unsettled. We have developed a "multi-band Stretch method", and investigated about 122 nearby (z < 0.11) SNe Ia samples. I will report what we found with the method.

I also report about the SDSS-II Supernova Survey, which is a 3 years project started from 2005 to 2007. This survey will obtain over 200 high-quality type Ia supernova light curves in the redshift range 0.05 < z < 0.35. We observed SNe detected by SDSS-II SN Survey with UH88 and Subaru(Yasuda et al.) last year. I will present the tentative report of the observations.

Seminars are also held at JAC, CFHT, and IfA.

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