|
| | | | |
| | | |
| Stat |
Members: 3645
Articles: 2'501'711
Articles rated: 2609
20 April 2024 |
|
| | | | |
|
Article overview
| |
|
|
Parsec-scale SiO Emission in an Infrared Dark Cloud | | I. Jimenez-Serra
; P. Caselli
; J. C. Tan
; A. K. Hernandez
; F. Fontani
; M. J. Butler
; S. van Loo
; | | Date: |
17 Mar 2010 | | Abstract: | We present high-sensitivity 2’x4’ maps of the J=2-1 rotational lines of SiO,
CO, 13CO and C18O, observed toward the filamentary Infrared Dark Cloud (IRDC)
G035.39-00.33. Single-pointing spectra of the SiO J=2-1 and J=3-2 lines toward
several regions in the filament, are also reported. The SiO images reveal that
SiO is widespread along the IRDC (size >2 pc), showing two different
components: one bright and compact arising from three condensations (N, E and
S), and the other weak and extended along the filament. While the first
component shows broad lines (linewidths of ~4-7 kms-1) in both SiO J=2-1 and
SiO J=3-2, the second one is only detected in SiO J=2-1 and has narrow lines
(~0.8 kms-1). The maps of CO and its isotopologues show that low-density
filaments are intersecting the IRDC and appear to merge toward the densest
portion of the cloud. This resembles the molecular structures predicted by
flow-driven, shock-induced and magnetically-regulated cloud formation models.
As in outflows associated with low-mass star formation, the excitation
temperatures and fractional abundances of SiO toward N, E and S, increase with
velocity from ~6 to 40 K, and from ~1E-10 to >1E-8 respectively, over a
velocity range of ~7 kms-1. Since 8 micron sources, 24 micron sources and/or
extended 4.5 micron emission are detected in N, E and S, broad SiO is likely
produced in outflows associated with high-mass protostars. The excitation
temperatures and fractional abundances of the narrow SiO lines, however, are
very low (~9 K and ~1E-11, respectively), and consistent with the processing of
interstellar grains by the passage of a shock with vs~12 kms-1. This emission
could be generated i) by a large-scale shock, perhaps remnant of the IRDC
formation process; ii) by decelerated or recently processed gas in large-scale
outflows driven by 8 micron and 24 micron sources; or iii) by an undetected and
widespread population of lower mass protostars. High-angular resolution
observations are needed to disentangle between these three scenarios. | | Source: | arXiv, 1003.3463 | | Services: | Forum | Review | PDF | Favorites | |
|
|
No review found.
Did you like this article?
Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.
browser Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)
|
| |
|
|
|
|
News, job offers and information for researchers and scientists:
| |
REGISTER