A Neutral Hydrogen Self-Absorption Cloud in the SGPS

Details A Neutral Hydrogen Self-Absorption Cloud in the SGPS A Neutral Hydrogen Self-Absorption Cloud in the SGPS

2003-08-26

arxiv.org/abs/astro-ph/0308466v1

Astrophys.J.598:1048-1060,2003

Astronomy and Astrophysics

Astrophysics

33 pages, 17 figures, 5 tables; Accepted for publication in ApJ. A version with higher quality images availabe at http://www

Scientific paper

10.1086/379114

Using data from the Southern Galactic Plane Survey (SGPS) we analyze an HI self-absorption cloud centered on l = 318.0 deg, b = -0.5 deg, and velocity, v = -1.1 km/s. The cloud was observed with the Australia Telescope Compact Array (ATCA) and the Parkes Radio Telescope, and is at a near kinematic distance of less than 400 pc with derived dimensions of less than 5 x 11 pc. We apply two different methods to find the optical depth and spin temperature. In both methods we find upper limit spin temperatures ranging from 20 K to 25 K and lower limit optical depths ~ 1. We look into the nature of the HI emission and find that 60-70% originates behind the cloud. We analyze a second cloud at the same velocity centered on l = 319 deg and b = 0.4 deg with an upper limit spin temperature of 20 K and a lower limit optical depth of 1.6. The similarities in spin temperature, optical depth, velocity, and spatial location are evidence the clouds are associated, possibly as one large cloud consisting of smaller clumps of gas. We compare HI emission data with 12CO emission and find a physical association of the HI self-absorption cloud with molecular gas.

Affiliated with

Also associated with

No associations

Rating

A Neutral Hydrogen Self-Absorption Cloud in the SGPS does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with A Neutral Hydrogen Self-Absorption Cloud in the SGPS, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A Neutral Hydrogen Self-Absorption Cloud in the SGPS will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-58699