Subaru Seminars



This Month






Site Map

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 @).

October 09, Monday at 10:30am

" Polycyclic Aromatic Hydrocarbons in various astrophysical environment "

Itsuki Sakon (University of Tokyo)

Polycyclic aromatic hydrocarbons(PAHs) are thought to be the carriers of the unidentified infrared (UIR) bands, which have been observed in various astrophysical environments including HII regions, Reflection Nebulae, Planetary Nebulae, diffuse ISM, and external galaxies even at the distance of z=2.8. Their ubiquitous presence suggests that the diagnostic use of the UIR features is quite useful to probe the interstellar environment even in a distant galaxy. In the first half of my talk, I am planing to show you our recent result on the mid-infrared spectroscopy of non-isolated Herbig Ae/Be object MWC1080 using Subaru/COMICS and discuss the ionization of PAHs around the central B0 star traced by the UIR 11.0um/11.2um ratio. In the last half, I would like to introduce our recent results on the mid-infrared observation of super star clusters in two blue compact dwarf galaxies, Henize 2-10 and IIZw40 using Subaru/COMICS. I especially focus on the properties of PAHs to understand their evolution in such an active and young starburst environment. Through these attempts, we aim to demonstrate the formation, evolution, and destruction process of PAHs andto make the uqbiquitous PAH features as the valid measure of the physical quantities such as the interstellar radiation strength, the electron density, etc.

" Detection of PAH emission features in nearby dusty elliptical galaxies "

Hidehiro Kaneda (ISAS / JAXA)

According to the current understanding, the presence of a considerable amount of dust in elliptical galaxies is quite common. Studies with ISO and Spitzer suggest even the presence of PAHs emission features in the SED of several elliptical galaxies. Hot ionized gas filling the interstellar space of elliptical galaxies, however, is expected to easily destroy such very small particles through sputtering by plasma ions. In this talk, I present the results of mid-IR spectroscopic observations of X-ray-emitting nearby dusty elliptical galaxies with the Spitzer Infrared Spectrograph (IRS). We have succeeded in detection of the PAH emission from the elliptical galaxies. The observed spectra seem to be quite unusual; the PAH features at 6.2, 7.7, and 8.6 um are very faint in contrast to prominent emission features at 11.3 and/or 12.7 um, which may reflect peculiar physical conditions of the ISM. The detection of the PAHs provides strong constraints on the evolution scenarios of the ISM of elliptical galaxies.

" Spatial Evolution of UIR bands in Red Rectangle "

In-Ok Song (Kyung Hee University)

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

Copyright (c) 1999-2000 Subaru Telescope, NAOJ. All rights reserved.