http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
LIFECYCLE OF THE INTERSTELLAR DUST GRAINS IN OUR GALAXY VIEWED WITH AKARI/MIR ALL-SKY SURVEY
Ishihara, D.,Kaneda, H.,Mouri, A.,Kondo, T.,Suzuki, S.,Oyabu, S.,Onaka, T.,Ita, Y.,Matsuura, M.,Matsunaga, N. The Korean Astronomical Society 2012 天文學論叢 Vol.27 No.4
The interstellar dust grains are formed and supplied to interstellar space from asymptotic giant branch (AGB) stars or supernova remnants, and become constituents of the star- and planet-formation processes that lead to the next generation of stars. Both a qualitative, and a compositional study of this cycle are essential to understanding the origin of the pre-solar grains, the missing sources of the interstellar material, and the chemical evolution of our Galaxy. The AKARI/MIR all-sky survey was performed with two mid-infrared photometric bands centered at 9 and $18{\mu}m$. These data have advantages in detecting carbonaceous and silicate circumstellar dust of AGB stars, and the interstellar polycyclic aromatic hydrocarbons separately from large grains of amorphous silicate. By using the AKARI/MIR All-Sky point source catalogue, we surveyed C-rich and O-rich AGB stars in our Galaxy, which are the dominant suppliers of carbonaceous and silicate grains, respectively. The C-rich stars are uniformly distributed across the Galactic disk, whereas O-rich stars are concentrated toward the Galactic center, following the metallicity gradient of the interstellar medium, and are presumably affected by the environment of their birth place. We will compare the distributions of the dust suppliers with the distributions of the interstellar grains themselves by using the AKARI/MIR All-Sky diffuse maps. To enable discussions on the faint diffuse interstellar radiation, we are developing an accurate AKARI/MIR All-Sky diffuse map by correcting artifacts such as the ionising radiation effects, scattered light from the moon, and stray light from bright sources.
THE CENTRAL REGION OF THE BARRED SPIRAL GALAXY NGC 1097 PROBED BY AKARI NEAR-INFRARED SPECTROSCOPY
Kondo, T.,Kaneda, H.,Oyabu, S.,Ishihara, D.,Mori, T.,Yamagishi, M.,Onaka, T.,Sakon, I.,Suzuki, T. The Korean Astronomical Society 2012 天文學論叢 Vol.27 No.4
With AKARI, we carried out near-infrared spectroscopy of the nearby barred spiral galaxy, NGC 1097, categorized as Seyfert 1 with a circumnuclear starburst ring. Our observations mapped the galactic center region. As a result, we obtain the spatial distributions of the polycyclic aromatic hydrocarbon $3.3{\mu}m$ and the aliphatic hydrocarbon $3.4-3.6{\mu}m$ emission. The former is detected from all the observed regions and the latter is enhanced near the bar connecting the ring with the nucleus. In addition, we detect absorption features due to $H_2O$ ice and CO/SiO at the ring and the galactic center, while we detect the hydrogen recombination line $Br{\alpha}$ only from the ring. Hence the observed spectra change dramatically within the central 1 kpc region.
PROCESSING OF INTERSTELLAR DUST GRAINS IN GALAXIES
Kaneda, H.,Ishihara, D.,Onaka, T.,Sakon, I.,Suzuki, T.,Kobata, K.,Kondo, T.,Yamagishi, M.,Yasuda, A. The Korean Astronomical Society 2012 天文學論叢 Vol.27 No.4
We have performed a systematic study of interstellar dust grains in various environments of galaxies. AKARI has revealed the detailed properties of dust grains not only in star-forming regions but also in regions not relevant to star formation, some of which are found not to follow our old empirical knowledge. Because of its unique capabilities, AKARI has provided new knowledge on the processing of large grains and polycyclic aromatic hydrocarbons (PAHs). For example, we detect PAHs from elliptical galaxies, which show unusual spectral features and spatial distributions, demonstrating importance of material processing in the interstellar space. We find that copious amounts of large grains and PAHs are flowing out of starburst galaxies by galactic superwinds, which are being shattered and destroyed in galactic haloes. We discover evidence for graphitization of carbonaceous grains near the center of our Galaxy, providing a clue to understanding the activity of the Galactic center. We review the results obtained from our AKARI program, focusing on the processing of carbonaceous grains in various environments of galaxies.
Measurement of Unbound Excited States of ^(24)O
추경호,사토,T. Nakamura,N. Aoi,방형찬,S. CHOI,S. Deguchi,F. Delaunay,J. Gibelin,T. Honda,M. Ishihara,Y. Kawada,Y. Kondo,T. Kobayashi,N. Kobayashi,F. M. Marques,M. Matsushita,Y. Miyashita,T. Motobayashi,Y. Nak 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.23
The unbound excited states of the most neutron-rich oxygen isotope, ^(24)O (Z = 8, N = 16), have been investigated using the ^(24)O(p,p') ^(24)O^* → ^(23)O+n reaction at RIKEN, where a 63 MeV/neuclon secondary beam of ^(24)O was produced in a Be production target by the projectile-like fragmentation of a 95 MeV/u ^(40)Ar primary beam. The first excited 2^* state was observed in the invariant mass spectrum. This experiment will give us a deeper understanding of the new magic number at N=16 in the neutron-rich oxygen isotopes.
SYSTEMATIC STUDY OF INTERSTELLAR ICES IN NEARBY GALAXIES
Yamagishi, M.,Kaneda, H.,Oyabu, S.,Ishihara, D.,Onaka, T.,Shimonishi, T.,Suzuki, T. The Korean Astronomical Society 2012 天文學論叢 Vol.27 No.4
The absorption features due to interstellar ices, especially $H_2O$ and $CO_2$ ices, provide us with crucial information on present and past interstellar environments, and thus the evolutionary histories of galaxies. Before AKARI, however, few detections of ices were reported for nearby galaxies. The AKARI's unique capability of near-infrared spectroscopy with high sensitivity enables us to systematically study ices in nearby galaxies. Thus we have explored many near-infrared spectra ($2.5-5{\mu}m$) of the 211 pointed observations, searching for the absorption features of ices. As a result, out of 122 nearby galaxies, we have significantly detected $H_2O$ ice from 36 galaxies and $CO_2$ ice from 9 galaxies. It is notable that the ices are detected not only in late-type galaxies but also in early-type galaxies. We find that $CO_2$ ice is more compactly distributed near the galactic center than $H_2O$ ice. Finally, we suggest that the gas density of a molecular cloud and UV radiation may be important factors to determine the abundance of ices.