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

我们对银道面的远红外[CII]谱线进行了大尺度巡天观测，发现[CII]谱线向银道中心方向非常弱。我们把这个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TIFR对银河系中心的[CII]线发射进行高空间观测（印度塔塔基础研究所）1米气球载望远镜，并在1999年成功地进行了首次观测。我们在这次活动中无法观测到银河系中心，但我们现在计划根据这次活动中获得的经验观测银河系中心区域。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。虽然我们不能观测到整个区域，但我们可以用光谱覆盖整个远红外区，这一观测与球载观测是互补的，我们还对光解离区的远红外辐射进行了理论计算，以解释上述观测。

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.