Supernovae (SN) and supernova remnants (SNRs) play a major role in the life-cycle of interstellar dusts. Fast shock waves generated by SN explosions sweep out the interstellar space destroying dust grains and modifying their physical and chemical properties. The dense, cooling SN ejecta, on the other hand, provide an environment for dusts to condense. Recent space-infrared telescopes have revealed the hidden universe related to these fascinating microscopic processes. In this paper, I introduce the results on stardusts in young core-collapse supernova remnants obtained by AKARI. The AKARI results show diverse infrared characteristics of stardusts associated with SNRs, implying diverse physical/chemical stellar structures and circumstellar environments at the time of explosion.

We determined the precise three dimensional WGS84 Coordinates and the sea level height of Seoul Radio Astronomy Observatory (SRAO). In this study, we performed the simultaneous GPS observations at SRAO and Seoul GPS Reference Station(SGRS) of Korea Astronomy Observatory(KAO) for 3.5 hours from 17KST on October 27, 1999. We employed two different antennas, i.e., chokering antenna at SGRS of KAO and L1/L2 compact with groundplane antenna at SRAO. But we employed same type of receivers, i.e., Trimble 4000SSI at both observing places. The observed data were processed by GPSURVEY 2.30 software of Trimble with L1/L2 ION Free technique and broadcasting ephemeris of GPS Satellites because of very short baseline between SGRS of KAO and SRAO. We determined WGS84 latitude, longitude, height and the sea level height of SRAO with 37∘27′15.′6846N±0.′0004,126∘57′19.′0727E±0.′0002,204.89m±0.02m,181.38m±0.17m 37∘27′15.′6846N±0.′0004,126∘57′19.′0727E±0.′0002,204.89m±0.02m,181.38m±0.17m , respectively.

We have carried out measurements of 1.2-1.6GHz radio interferences around Seoul Radio Astronomy Observatory located in the campus of Seoul National University. We received interference signals using a pyramidal horn antenna and measured its power using a spectrum analyzer with 1MHz resolution after ~60dB amplification. In order to check the spatial characteristics, we made observations at every 30∘ 30∘ in azimuth at elevation of 30∘and60∘ 30∘and60∘ . Also, in order to check the temporal characteristics, we repeated the all-sky observations five times at every six hours. The results may be summarized as follows: (1) There are strong (≥−20dBm) (≥−20dBm) interferences between 1.2 and 1.4GHz. Particularly strong interferences are observed at 1.271 and 1.281GHz, which have maximum powers of -0.34dBm and -0.56dBm, respectively. (2) The characteristics of the interferences do not depend strongly on directions, although the interferences are in general weak at high elevation and in east-west direction. (3) The interferences appear for a very short (≤0.01s) (≤0.01s) period of time, so that the average power is much smaller than the maximum power. Strong interferences with large (≤−49.0dBm) (≤−49.0dBm) average power have been observed at 1.271, 1.281, 1.339, and 1.576GHz. At these frequencies, the interferences appear repeatedly with a period of ≤0.1s ≤0.1s By analyzing the observed power, we find that, for the strongest 1.271GHz interference, the average intensity is −171dBW/m2/Hz −171dBW/m2/Hz and that the maximum intensity is −122dBW/m2/Hz −122dBW/m2/Hz . If this interference is delivered to the detector without any shielding, then its power would be much greater than the rms noise of a typical line spectrum. Therefore, it is important to shield all the parts of receiver carefully from radio interferences. Also, without appropriate shielding, the sensitivity of a receiver could be limited by the interference.

We report the results of H I 21-cm and molecular line studies of the shocked interstellar gas in the W51 complex. We present convincing evidences suggesting that the shocked gas has been produced by the interaction of the W51C supernova remant (SNR) with a large molecular cloud, Our results show that W51C is the second SNR with direct evidences for the shocked cloud material.

We have decomposed the 11-cm radio continuum emission of the W51 complex into thermal and non-thermal components. The distribution of the thermal emission has been determined by analyzing HI, CO, and IRAS 60-μm data. We have found a good correlation between the 11-cm thermal continuum and the 60- 11m emissions, which is used to obtain the thermal and non-thermal 11-cm continuum maps of the W51 complex. Most of the thermal continuum is emanating from the compact H II regions and their low-density ionized envelopes in W51A and W51B. All the H II regions, except G49.1-0.4 in W51B, have associated molecular clumps. The thermal radio continuum fluxes of the compact H II regions are proportional to the CO fluxes of molecular clumps. This is consistent with the previous results that the total mass of stars in an H II region is proportional to the mass of the associated molecular clump. According to our result, there are three non-thermal continuum sources in W51: G49.4-0.4 in W51A, a weak source close to G49.2-0.3 in W51B, and the shell source W51C. The non-thermal flux of G49.5-0.4 at 11-cm is ~28 Jy, which is ~25% of its total 11-cm flux. The radio continuum spectrum between 0.15 and 300 GHz also suggests an excess emission over thermal free-free emission. We show that the excess emission can be described as a non-thermal emission with a spectral index α≃-1.0 (Sv∝Va) attenuated by thermal free-free absorptions at low-frequencies. The non-thermal source close to G49.2-0.3 is weak (~9 Jy). The nature of the source is not known and the reality of the non-thermal emission needs to be confirmed. The non~thermal shell source W51C has a 11-cm flux of ~130Jy and a spectral index α≃-0.26.