Mid- to Far-Infrared spectroscopy of Sharpless 171

Details Mid- to Far-Infrared spectroscopy of Sharpless 171 Mid- to Far-Infrared spectroscopy of Sharpless 171

2003-10-22

arxiv.org/abs/astro-ph/0310627v1

Astron.Astrophys. 412 (2003) 199-212

Astronomy and Astrophysics

Astrophysics

15 pages with 15 figures, accepted in Astronomy & Astrophysics

Scientific paper

10.1051/0004-6361:20031415

We have collected one-dimensional raster-scan observations of the active star-forming region Sharpless 171 (S171), a typical HII region-molecular cloud complex, with the three spectrometers (LWS, SWS, and PHT-S) on board ISO. We have detected 8 far-infrared fine-structure lines, [OIII] 52um, [NIII] 57um, [OI] 63um, [OIII] 88um, [NII] 122um, [OI] 146um, [CII] 158um, and [SiII] 35um together with the far-infrared continuum and the H2 pure rotation transition (J=5-3) line at 9.66um. The physical properties of each of the three phases detected, highly-ionized, lowly-ionized and neutral, are investigated through the far-infrared line and continuum emission. Toward the molecular region, strong [OI] 146um emission was observed and the [OI] 63um to 146um line ratio was found to be too small (about 5) compared to the values predicted by current photodissociation region (PDR) models. We examine possible mechanisms to account for the small line ratio and conclude that the absorption of the [OI] 63um and the [CII] 158um emission by overlapping PDRs along the line of sight can account for the observations and that the [OI] 146um emission is the best diagnostic line for PDRs. We propose a method to estimate the effect of overlapping clouds using the far-infrared continuum intensity and derive the physical properties of the PDR. The [SiII] 35um emission is quite strong at almost all the observed positions. The correlation with [NII] 122um suggests that the [SiII] emission originates mostly from the ionized gas. The [SiII] 35um to [NII] 122um ratio indicates that silicon of 30% of the solar abundance must be in the diffuse ionized gas, suggesting that efficient dust destruction is undergoing in the ionized region.

Affiliated with

Also associated with

No associations

Rating

Mid- to Far-Infrared spectroscopy of Sharpless 171 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 Mid- to Far-Infrared spectroscopy of Sharpless 171, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mid- to Far-Infrared spectroscopy of Sharpless 171 will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-664333