@misc{oai:ir.soken.ac.jp:00000388,
 author = {有川, 裕司 and アリカワ, ユウジ and ARIKAWA, Yuji},
 month = {2016-02-17, 2016-02-17},
 note = {Supernova remnants (SNRs), which are very energetic objects, are thought to have great influence on the interstellar medium. The expanding shock waves of SNRs compress, heat, and accelerate the interstellar gas. Because the interaction of SNR with the molecular cloud may play an important role in the next-generation star for- mation, it is of considerable interest to study the physical and chemical processes of 
the interaction.
In order to search for the interaction between SNR and the molecular cloud, we observed two SNRs, W28 and γ Cygni SNR, which are supposed to be EGRET gamma- ray sources, in submillimeter-wave CO ( J = 3 - 2 ) line (345 GHz; 0.9 mm) by using the 15 m James Clerk Maxwell Telescope (JCMT). In W28, we detected a broad emission (maximum linewidth reaches ΔV ～70kms-1), which suggests an interaction between SNR and the molecular cloud (“shocked gas”), as well as a narrow emission from the “unshocked gas”. However, the broad emission was not observed toward γCygni SNR.
For W28, the distribution of the CO gas is similar to that of the 327 MHz radio- continuum emission, and tends to be stronger along the radio-continuum ridge. This suggest that the compression of magnetic fields in the SNR by the cloud results in enhanced synchrotron radiation. In addition, all of the OH (1720 MHz) maser spots, which trace the interaction between SNR and the molecular cloud, are located along the 
filament of the shocked gas. These facts convincingly indicate that SNR W28 interacts with the molecular cloud. Our observations are consistent with a hypothesis that the interaction of the SNR with the molecular cloud can be the origin of gamma-rays. Moreover, the distribution of the unshocked and shocked gas is clearly resolved. The shocked gas is filamentary, and surrounds the center of the supernova, explosion. The unshocked gas is displaced by 0.4 - 1.0 pc outward with respect to the shocked gas. The spatial relationship between shocked and unshocked gas has been clarified for the first time for the interaction between SNRs and molecular clouds.
In order to obtain the distribution of the cold gas and the physical properties of the molecular gas associated with W28, we observed the millimeter-wave CO (J=1 - 0 ) line (115 GHz ; 2.6 mm) by using the 45 m telescope of the Nobeyama Radio Observatory (NRO). It is found that the line intensity of CO (J=1 - 0 ) emission is stronger than that of CO (J=3 - 2) emission in the narrow component, and while the CO (J=3 - 2) emission is stronger than CO (J =1 - 0) emission in the broad component. The distribution of CO (J =1 - 0) globally resembles that of CO (J = 3 - 2 ). The unshocked gas has a gas kinetic temperature of Tkin ～20 K and a density of n(H2) ～ 10 3 cm-3, and a total mass of Munshocked = 4 × 103 M〓. On the other hand, the shocked gas has Tkin > 60 K, n(H2) > 104 cm-3, and Mshocked = 2 × 103 M〓. The total kinetic energy deposited in the shocked molecular gas is 3 × 1048 erg, which corresponds to 0.3 % of the energy of the supernova explosion.<br />To understand the chemistry related to carbon in the interaction region between SNR and the molecular cloud, we observed in CO(J=3-2) at 345 GHz(0.9 mm) and CI(3P1 - 3P0) at 492 GHz (0.6 mm) toward the four SNRs, W28, IC443, W44, and W51C by using the Mt. Fuji submillimeter-wave telescope, which we developed. This telescope is the first submillimeter-wave telescope in Japan. With this telescope, we can observe CI(3P1 - 3P0) and CO(J=3 - 2) simultaneously. The spatial resolution is suitable for the observation of the molecular cloud scale.  Except for IC 443, the CI(3P1 - 3P0) emission was detected. We found that the distribution of the CI(3P1 - 3P0) emission is similar to that of the CO(J=3 - 2) emission. It is clear that the known OH[(1720 MHz) maser spots are located at the edge of clumps in all 4 SNRs. In the interaction region between SNR and the molecular cloud, the CI(3P1 - 3P0)/CO(J=3 - 2) peak intensity ratio and the N(CI)/N(CO) column density ratio tend to be high. On the other hand, in molecular clouds unrelated with SNR, the ratios are lower. This result might imply that the interaction of SNR with the molecular cloud enhances the CI abundance.
At present, though 220 SNRs are cataloged in our Galaxy, the observational examples of the interaction between SNR and molecular clouds are small in number. The shock region in W28 has rather simple structure and “edge-on”. In the future, W28 can be one of the best regions for detailed studies of the interaction between SNR and the molecular cloud. By increasing the number of the observational examples, we can obtain better understanding of the molecular cloud associated with SNR., application/pdf, 総研大甲第454号},
 title = {Submillimeter-wave Observations of the ShockedMolecular Gas Associated with Supernova Remnants},
 year = {}
}