Far-Infrared Spectroscopic Study of Interstellar Medium and Star-formation Rate in the Galactic Center

我们从银面对远红外光谱线进行了大规模的巡天观测，发现[CII]线对银河系中心异常微弱。我们将这一弱点归因于银河系中心区域的软星际辐射场。如果是这样的话，我们的观测表明，目前银河系中心区域的恒星形成率相对较低。为了验证上述建议，我们计划使用印度塔塔基础研究所（TATA Institute of Fundamental Research, India）的1米气球载望远镜对银河系中心的[CII]线发射进行高空间观测，并在1999年的活动中成功进行了首次观测。在这次活动中，我们无法观测到银河系中心，但我们现在正计划根据这次活动中获得的经验来观测这个区域。我们还用星载望远镜ISO（红外空间天文台）观测了银河系中心区域。虽然我们无法对整个区域进行观测，但我们可以对整个远红外区域进行光谱覆盖，这是对气球观测的补充。我们还对光解区域的远红外辐射进行了理论计算，以解释上述观测结果。

We made large-scale survey observations of the far-infrared [CII] spectral line from the Galactic plane, and found that the [CII] line is anomalously weak toward the Galactic center. We attribute this weakness to the soft interstellar radiation field in the Galactic center region. If it is the case, our observations suggest that the current star-formation rate in the Galactic center region is relatively low.In order to check the above suggestion, we planned high spatial observations of the [CII] line emission from the Galactic center using the TIFR (TATA Institute of Fundamental Research, India) 1m balloon-borne telescope, and made the first observation with this system successfully during the campaign in 1999. We could not observe the Galactic center in this campaign, but we are now planning to observe the region on the basis of the experience gained during this campaign.We also observed the Galactic center region with the space-borne telescope ISO (infrared Space Observatory). Although we could not observe the whole region, we could cover the whole far-infrared region spectroscopically, and this observation is complement with balloon-borne observations.We also made theoretical calculations of far-infrared emission from photo-dissociation regions to interpret the above observations.