Issue |
A&A
Volume 494, Number 2, February I 2009
|
|
---|---|---|
Page(s) | 637 - 646 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361:200810930 | |
Published online | 20 November 2008 |
Online Material
Appendix A: RADEX - construction of a dust model
In order to relate the molecular column densities, N(x) of species x, to fractional abundances, X(x) =
,
a uniform, homogeneous sphere of diameter L =
is assumed here. The adopted physical diameter of the PDR corresponding to an angular diameter of 120
(Sect. 3) at a distance of 910 pc is 0.53 pc. This is assumed to be equal to the line-of-sight depth.
The observed intensity of the continuum is used to estimate the internal radiation field sensed by
the molecules. We construct a simple model of the broad-band spectrum at submm and far-infrared wavelengths in order both to characterise the internal radiation and to estimate the total
column densities of dust and hydrogen. Thronson et al. (1983) measured the far-infrared emission of S140 and found a peak flux density of the order of 104 Jy slightly shortward of 100
m in a 49
beam. Minchin et al. (1995) presented total broad-band fluxes in a
box. We represent the latter results with a
two-component model of thermal emission by dust over a solid angle of
10-7 sr. The main component has a dust temperature
= 40 K and a long-wavelength (
m) form of the opacity law

where






where






For the adopted interstellar extinction law and a standard gas/extinction ratio,

the adopted dust model implies






Appendix B: Figures and tables
![]() |
Figure B.1: Odin observations of H218O in the central position. |
Open with DEXTER |
![]() |
Figure B.2:
Rotation diagram of the broad component of 13CO(1-0) with the Onsala 20-m telescope, J = 2-1 and J = 3-2 from Minchin et al. (1993), and J = 5-4 with Odin, producing
|
Open with DEXTER |
![]() |
Figure B.3:
Rotation diagram of the narrow component of 13CO(2-1) and J = 3-2 from Minchin et al. (1993), J = 5-4
with Odin, and J = 6-5 from Graf et al. (1993), producing
|
Open with DEXTER |
![]() |
Figure B.4: Gaussian fits to 13CO(5-4) at the central position. The widths, amplitudes and centre velocities are 3.2 km s-1 and 8.2 km s-1; 6.610 K and 0.612 K; -7.3 km s-1 and -6.8 km s-1, respectively. |
Open with DEXTER |
![]() |
Figure B.5:
Gaussian fits to the convolved (to the Odin 126
|
Open with DEXTER |
![]() |
Figure B.6: Gaussian fits to H2O at the central position. The widths, amplitudes and centre velocities are 3.1 km s-1 and 8.8 km s-1; 416 mK and 213 mK; -7.1 km s-1 and -6.1 km s-1, respectively. |
Open with DEXTER |
![]() |
Figure B.7: Gaussian fits to NH3 at the central position. The widths, amplitudes and centre velocities are 3.3 km s-1 and 8.5 km s-1; 487 mK and 100 mK; -7.6 km s-1 and -6.4 km s-1, respectively. |
Open with DEXTER |
Table B.1: Observed transitions and their parametersa in S140 with the Odin satellite in a five point NE-SW strip.
Table B.2:
13CO Gaussian fitsa.
uses a source size for the PDR (narrow component) of 120
= 2, and a source size for the broad outflow component of 85
= 3.
Table B.3:
H2O Gaussian fitsa. (PDR) uses a source size of 120
= 2, while
(outflow) uses a source size of 85
= 3.
Table B.4:
NH3 Gaussian fitsa. (PDR) uses a source size of 120
= 2, while
(outflow) uses a source size of 85
= 3.
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