The Five College Radio Astronomy Observatory CO Survey of the Outer Galaxy

被引:274
作者
Heyer, MH
Brunt, C
Snell, RL
Howe, JE
Schloerb, FP
Carpenter, JM
机构
[1] Univ Massachusetts, Five Coll Radio Astron Observ, Amherst, MA 01003 USA
[2] Univ Massachusetts, Dept Phys & Astron, Amherst, MA 01003 USA
[3] Univ Hawaii, Inst Astron, Honolulu, HI USA
关键词
Galaxy; structure; ISM; clouds; general; kinematics and dynamics; molecules; surveys;
D O I
10.1086/313086
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Images from the FCRAO CO Survey of the Outer Galaxy and a description of the calibration and processing of the data are presented. The survey is comprised of 1,696,800 (CO)-C-12 J = 1-0 spectra sampled every 50 " between Galactic longitudes 102 degrees.49 and 141 degrees.54 and latitudes -3 degrees.03 and 5 degrees.41. The V-LSR ranges from -153 to +40 km s(-1) sampled every 0.81 km s(-1) with a velocity resolution of 0.98 km s(-1). The survey provides the highest spatial dynamic range imaging of the molecular interstellar medium ever obtained. We describe the observing procedure and characterize the random and systematic noise of the survey. The images reveal a wide diversity of spatial structure within the molecular interstellar medium. We identify several voids with angular extents of 2 degrees-5 degrees in diameter that may result from the cumulative interactions of ultraviolet radiation fields and stellar winds from newborn massive stars with ambient interstellar gas. It is demonstrated that a significant fraction of the integrated intensity summed over the survey field originates from regions with low peak antenna temperature and low column density assuming a conversion between integrated CO emission and molecular hydrogen column density. Assuming kinematic distances to the observed emission, wie derive the radial profile of mass surface density and the variations of the z midplane and scale height of the molecular gas distribution with galactocentric radius.
引用
收藏
页码:241 / +
页数:35
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