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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 (Tae-Soo Pyo, Sherry Yeh, Nagayoshi Ohashi) by email : sseminar_at_subaru.naoj.org (please change"_at" to @).

November 14, Thursday, at 11:00 am

" Nature of Halpha-selected galaxies at z>2 "

Kenichi Tadaki

(NAOJ)


Star-forming galaxies become increasingly irregular at z > 2 with clumpy structures as well as enhancements of star formation activities. How do such distant clumpy galaxies evolve? In numerical simulations, the clumps can migrate toward the galaxy center as a result of their mutual interactions and of dynamical friction against the host disk, and coalesce into a young bulge. On the other hand, strong stellar feedback, parameterized by momentum-driven galactic winds, can disrupt clumps before migrating towards the galaxy centers. To give observational constraints on the fate of the clumps, we have identified a lot of clumpy galaxies from a narrow-band imaging survey of H-alpha emitters (HAEs) at z > 2 with MOIRCS on Subaru Telescope in the SXDF-CANDELS field, where the high-resolution near-infrared and optical images by WFC3/ACS on HST are both publicly available. Interestingly, the colors of clumps are often significantly different: we find the trends of having redder colors in the galactic nuclei compared to the off-center clumps. Moreover, some clumpy HAEs are detected with MIPS 24 um image, which strongly suggests that dusty starburst is occurring within these galaxies. Therefore, our result implies that the intense star formation is on-going in the red clump near the galaxy center. Dusty starburst activity in a nuclear clump supports the scenario that the clumps migrate to galactic center or merge with other clumps, and then such events induce an intense star-formation like a gas-rich merger process.


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



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