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 : sseminar_at_subaru.naoj.org (please change"_at_" to @).
August 03, Wednesday, at 11:00 am
" Near- to Mid-Infrared Spectroscopy of ULIRGs: Collaborative Observations with AKARI and Subaru "
We present the results of near- to mid-infrared spectroscopic
observations of heavily obscured ultra-luminous infrared
galaxies (ULIRGs). ULIRGs radiate most of their extremely large,
quasar-like luminosities (>10^12 L_sun) as infrared dust emission.
Since the energy source of the ULIRGs are thought to be buried
within the thick dust and thus not easy to observed from
UV to optical, the observations at longer wavelength,
i.e., infrared observations play an important role to study them.
We have carried out continuous and high-sensitivity
infrared spectroscopic observations at 2-13um toward
24 obscured ULIRGs with AKARI/IRC slit-less spectroscopy,
which is one of the unique capability of AKARI.
The 2-5um spectra are especially valuable, because Spitzer
does not have spectroscopic capability in this wavelength region.
The spectra show many absorption and emission features from dust,
molecules, atoms, and ions. In addition to the many PAH emission
features (tracers of starburst activity) and some dust absorption
features (tracers of obscured AGNs), we have successfully detected
absorption feature due to water ice (indicating the presence of
cold molecular gas) and absorption feature caused by
gaseous CO (evidence of the existence of warm molecular gas).
In order to reveal physical conditions of molecular clouds
in ULIRGs directly, we are now making high-resolution
spectroscopic observations of fundamental ro-vibration
absorption lines of gaseous CO in M-band using the IRCS+AO188
on the Subaru Telescope. This is a unique technique
which enable us to determine temperature and column densities
of molecular clouds very accurately.
We will show these observation results and discuss
the physical condition of the molecular clouds in ULIRGs,
Seminars are also held at JAC,