Astronomy and Astrophysics – Astrophysics – Galaxy Astrophysics
Scientific paper
2011-02-12
Astronomy and Astrophysics
Astrophysics
Galaxy Astrophysics
13 pages, 13 figures with multiple parts, accepted for publication in Astrophysical Journal, Feb. 2011
Scientific paper
This paper presents spectra in the 2 to 20 micron range of quiescent cloud material located in the IC 5146 cloud complex. The spectra were obtained with NASA's Infrared Telescope Facility (IRTF) SpeX instrument and the Spitzer Space Telescope's Infrared Spectrometer. We use these spectra to investigate dust and ice absorption features in pristine regions of the cloud that are unaltered by embedded stars. We find that the H2O-ice threshold extinction is 4.03+/-0.05 mag. Once foreground extinction is taken into account, however, the threshold drops to 3.2 mag, equivalent to that found for the Taurus dark cloud, generally assumed to be the touchstone quiescent cloud against which all other dense cloud and embedded young stellar object observations are compared. Substructure in the trough of the silicate band for two sources is attributed to CH3OH and NH3 in the ices, present at the ~2% and ~5% levels, respectively, relative to H2O-ice. The correlation of the silicate feature with the E(J-K) color excess is found to follow a much shallower slope relative to lines of sight that probe diffuse clouds, supporting the previous results by Chiar et al. (2007).
Allamandola Louis J.
Boogert Adwin C. A.
Chiar Jean E.
Decin Leen
Ennico Kim
No associations
LandOfFree
Ices in the Quiescent IC 5146 Dense Cloud 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 Ices in the Quiescent IC 5146 Dense Cloud, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ices in the Quiescent IC 5146 Dense Cloud will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-84757