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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 @).
March 10, Tuesday, 11:00 am in 104
" Physical conditions of the interstellar medium in star-forming galaxies at z~1.5 "
Masao Hayashi
(NAOJ)
We present results from Subaru/FMOS NIR spectroscopy
for 118 [OII] emission line galaxies at z=1.47 and 1.62
in the Subaru Deep Field. We use six nebular emission
lines in the individual and composite spectra in the
rest-frame optical to investigate physical conditions
of the ISM in the star-forming galaxies at z~1.5.
We have found that the [OII] emitters have strong
[OIII] emission lines, showing the [OIII]/[OII] ratios
larger than normal star-forming galaxies in the local
Universe. There is a dependence of the line ratio on
stellar mass in the sense that less massive galaxies have
larger [OIII]/[OII] ratios. With evidence that the electron
density estimated from the flux ratio of [SII] doublet
is consistent with the local galaxies, the high ionization
parameter of galaxies at high redshifts is likely to be
attributed to harder radiation field by young stellar
populations and/or the increasing number of ionizing photon
from massive stars. Moreover, we have found that there is
a tight correlation between Halpha and [OII], which suggests
that [OII] can be a good indicator of star formation rate
for galaxies at z~1.5. The line ratios of Halpha/[OII] are
consistent with those of the local galaxies.