Probing the origin of peculiar dust with high far-infrared emissivity

探究高远红外发射率的奇特尘埃的来源

基本信息

批准号：
17540214
负责人：
DOBASHI Kazuhito
金额：
$ 2.11万
依托单位：
Tokyo Gakugei University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

项目摘要

Comparing the visual extinction map of Av measured directly in the optical wavelengths using the data base Digitized Sky Survey I and that derived from the far-infrared dust emission, we found that the dark clouds in the Galaxy are surrounded by dust whose emissivity in the far-infrared wavelengths (>100 micron) is a few times higher than normal dust grains. Such unusual dust seems to be very abundant in the Galaxy, being ubiquitous all over the galactic plain. Purpose of the present study is to probe into the origin such peculiar dust by measuring their reddening curves in the optical and near-infrared wavelengths as well as by probing into the density and temperature of molecular gas in the clouds which may influence on the dust property inside of the clouds.During the first year of the research period (2005), we concentrated on the development of the 60cm-diameter telescope with other radio astronomical groups in Japan in order to carry out radio observations toward several dark clouds including L1251, IC5146, and rho-0ph. In the second year (2006), we actually performed the ^<12>CO and ^<13>CO (J=2-1) observations with a moderate angular resolution of 10'. In order to probe into the dust distribution and the possible change in the dust properties in the clouds, we also produced maps of color excess E(J-H) and E(H-K) using the database 2 Micron All Sky Survey (2MASS). Comparing all of these dataset, we conclude that the peculiar dust observed inside of the clouds is probably big grain growing inside of the dense cores. On the other hands, dust with high far-infrared emissivity observed in the diffuse boundary of the clouds is likely to be fluffy aggregates, although their definite origin still remains as an open question.

比较使用数据库数字化的天空调查I和源自远红外灰尘发射的数据库直接在光学波长中测量的AV的视觉消光图，我们发现银河系中的乌云被尘埃包围 - 红外波长（> 100微米）比正常尘埃晶粒高几倍。这种不寻常的尘埃似乎在银河系中非常丰富，在银河平原上无处不在。本研究的目的是通过测量其在光学和近红外波长中的发红曲线，以及通过探测云中分子气的密度和温度，从在研究期的第一年（2005年）中，我们专注于日本其他射电天文学群体的直径望远镜的开发，以便对包括L1251，IC5146在内的几个乌云进行无线电观察。和Rho-0ph。在第二年（2006年）中，我们实际上进行了 ^<12> CO和 ^<13> CO（j = 2-1）的观测值，中等角度分辨率为10'。为了探测灰尘分布和云中灰尘特性的可能变化，我们还使用数据库2微米所有Sky Survey（2 Mass）制作了颜色多余的E（J-H）和E（H-K）的地图。比较所有这些数据集，我们得出的结论是，在云层内观察到的奇特灰尘可能是在密集岩心内生长的大谷物。另一方面，在云层的扩散边界中观察到的具有高远红外发射率的灰尘可能是蓬松的聚集体，尽管它们的确定起源仍然是一个悬而未决的问题。