A Study of Interstellar Dust Grains based on the Diffuse Galactic Light

1995年3月18日，我们成功地完成了由HII-3火箭发射的IRTS（太空中的红色望远镜）的使命。利用IRTS上的中红外光谱仪（MIRS），IRTS观测到了大约7个分辨率的漫射银河光光谱，首次提供了黄道光和漫射银河光的中红外光谱。为了制定观测计划和确认MIRS的飞行性能，我们在发射前准备了几个软件，根据飞行后的数据分析，我们清楚地表明，银河平面周围的中红外漫射光由6.2，7.7，8.6，这表明星际空间中普遍存在UIR发射材料，这被认为是碳质材料，并为星际尘埃颗粒模型的研究提供了关键信息。结合MIRS数据处理，我们分析了COBE数据，发现中红外漫辐射与星际辐射场的强度成正比，这支持了温度波动的极小尘埃颗粒模型。在这项研究的同时，我们还表明，偏振的热发射可以提供的信息，分离成几个组件的漫发射。综上所述，我们明确建立了利用漫射背景辐射研究星际尘埃颗粒的新观测方法，实现了本项目的初步目标。我们正计划对MIRS数据进行进一步分析，并对星际尘埃颗粒进行调查。

We had a successful mission of the IRTS (InfraRed Telescope in Space), which was launched by the HII-3 rocket on March 18,1995. The IRTS observed about 7 resolution spectra of the diffuse Galactic light by the Mid-InfraRed Spectrometer (MIRS) aboard the IRTS.These provide the mid-IR spectra of the zodiacal light and the diffuse Galactic Light for the first time. We prepared several pieces of software prior to the launch in order to make the observation plan and confirm the flight performance of the MIRS.Based on the post-flight data analysis, we have clearly shown that the mid-infrared diffuse light around the Galactic plane consists of the so-called infrared unidentified bands (UIRs) of the 6.2,7.7,8.6, and 11.3 mm. This suggests the ubiquitous existence of the UIR emitting material in the interstellar space, which is thought to be carbonaceous material and provides key information for the investigation of the interstellar dust grain models. Together with the MIRS data reduction, we have analyzed the COBE data, finding that the mid-IR diffuse emission is proportional to the strength of the interstellar radiation field, which supports the temperature-fluctuating very small dust grain model for this emission. In parallel to this research, we have also shown that the polarization of the thermal emission could provide the information to separate the diffuse emission into several components. In summary, we have clearly established the new observational method for the research of interstellar dust grains by using the diffuse background emission and achieved the primary goal of this project. We are planning to make further analysis of the MIRS data and pursue the investigation of interstellar dust grains.