Subaru Seminars



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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 (Tadayuki Kodama, Kumiko S. Usuda, Naoyuki Tamura, Tomonori Usuda) by email : (please change"_at_" to @).

June 27, Monday, at 1:30 pm

" Star Formation of Galaxies with the Most Extreme Conditions "

Ji Hoon Kim

(Seoul National University, Korea)

Star formation is one of the most important physical processes in terms of galaxy formation and evolution. While there have been tremendous theoretical progress regarding formation of stars and galaxies to provide information on how star formation drive galaxy evolution along the Hubble time, it still remains a big puzzle how galaxies gather gas and turn it into stars and what physical properties regulate the process. In fact, the Kennicutt-Schmidt law was the rule of thumb until various surveys such as THINGS enable us to study star forming galaxies in kpc scale very recently. Studies based on these surveys including Bigiel et al. (2008) based on THINGS survey show that there is a strong correlation between star formation surface density and the sum of neutral and molecular gas surface density while starburst galaxies do not follow the correlation with much higher star formation efficiencies. Yet, it is not only energetic starburst galaxies which deviate from the trend. Galaxies at the low end of gas surface density also form stars with much lower star formation efficiencies even at lower gas surface density than apparent star formation threshold. Combined with their possible low metallicities, these galaxies are testbeds for star formation law and, furthermore, can provide crucial informations on star formation within primordial galaxies in the early Universe. These galaxies also show that there is a systematic trend between H-alpha/UV ratio and optical or/and NIR surface brightness, which suggests non-universal stellar initial mass functions. I will present recent progresses regarding this puzzling low surface brightness regime.

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

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