J/A+A/653/A108 Globules and pillars in Cygnus X (Schneider+, 2021)
Globules and pillars in Cygnus X.
III. Herschel and upGREAT/SOFIA far-infrared spectroscopy of the globule
IRAS 20319+3958 in Cygnus X.
Schneider N., Roellig M., Polehampton E.,, Comeron F., Djupvik A.A.,
Makai Z., Buchbender C., Simon R., Bontemps S., Guesten R., White G.,
Okada Y., Parikka A., Rothbart N.
<Astron. Astrophys. 653, A108 (2021)>
=2021A&A...653A.108S 2021A&A...653A.108S (SIMBAD/NED BibCode)
ADC_Keywords: Globules ; H II regions ; Interstellar medium ; Line Profiles ;
Spectra, millimetric/submm
Keywords: ISM: atoms - ISM: clouds - HII regions - photon-dominated region -
ISM: molecules - ISM: kinematics and dynamics
Abstract:
IRAS 20319+3958 in Cygnus X South is a rare example of a free-floating
globule (mass ∼240M☉, length ∼1.5pc) with an internal HII region
created by the stellar feedback of embedded intermediate-mass stars,
in particular, one Herbig Be star. In Schneider et al.
(2012A&A...542L..18S 2012A&A...542L..18S) and Djupvik et al. (2017A&A...599A..37D 2017A&A...599A..37D, Cat.
J/A+A/599/A37), we proposed that the emission of the far-infrared
(FIR) lines of [CII] at 158um and [OI] at 145um in the globule head
are mostly due to an internal photodissociation region (PDR). Here, we
present a Herschel/HIFI [CII] 158um map of the whole globule and a
large set of other FIR lines (mid-to high-J CO lines observed with
Herschel/PACS and SPIRE, the [OI] 63um line and the 12CO 16->15 line
observed with upGREAT on SOFIA), covering the globule head and partly
a position in the tail. The [CII] map revealed that the whole globule
is probably rotating. Highly collimated, high-velocity [CII] emission
is detected close to the Herbig Be star. We performed a PDR analysis
using the KOSMA-τPDR code for one position in the head and one in
the tail. The observed FIR lines in the head can be reproduced with a
two-component model: an extended, non-clumpy outer PDR shell and a
clumpy, dense, and thin inner PDR layer, representing the interface
between the HII region cavity and the external PDR. The modelled
internal UV field of ∼2500Go is similar to what we obtained from the
Herschel FIR fluxes, but lower than what we estimated from the census
of the embedded stars. External illumination from the ∼30pc distant
Cyg OB2 cluster, producing an UV field of ∼150-600Go as an upper
limit, is responsible for most of the [CII] emission. For the tail, we
modelled the emission with a non-clumpy component, exposed to a
UV-field of around 140Go.
Description:
We present submm-FIR observations with Herschel and SOFIA of the
globule IRAS 20319+3958 in Cygnus X South. It contains an internal HII
region created by the stellar feedback of embedded intermediate-mass
stars, in particular one Herbig Be star. The CII map revealed that the
whole globule is probably rotating. Highly collimated, high-velocity
CII emission is detected close to the Herbig Be star. We performed a
PDR analysis using the KOSMA-tau PDR code for one position in the head
and one in the tail. The observed FIR lines in the head can be
reproduced with a two-component model: an extended, non-clumpy outer
PDR shell and a clumpy, dense and thin inner PDR layer, representing
the interface between the HII region cavity and the external PDR.
External illumination from the 30pc distant Cyg OB2 cluster is
responsible for most of the CII emission.
Data cube of CII 158 micron emission observed with HIFI on Herschel.
File with line integrated intensities of CII 158 micron emission
observed with HIFI on Herschel. All data are fully calibrated and on a
main beam brightness temperature scale (K).
Objects:
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RA (2000) DE Designation(s)
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20 33 49.25 +40 08 44.2 IRAS 20319+3958 = WISE J203349.24+400844.1
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 119 2 List of fits files
fits/* . 2 Individual fits files
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 21 I2 --- Nx Number of pixels along X-axis
23- 24 I2 --- Ny Number of pixels along Y-axis
26- 28 I3 --- Nz ? Number of slices for the datacube
30- 37 F8.1 m/s bVRAD VRAD or lower value of VRAD interval
39- 45 F7.1 m/s BVRAD ? Upper value of VRAD interval
47- 52 F6.2 m/s dVRAD ? VRAD resolution
54- 57 I4 Kibyte size Size of FITS file
59- 70 A12 --- FileName Name of FITS file, in subdirectory fits
72-119 A48 --- Title Title of the FITS file
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Acknowledgements:
Nicola Schneider, nschneid(at)ph1.uni-koeln.de
I. Physik. Institut, Cologne, Germany
(End) N. Schneider [Physik. Inst., Cologne] P. Vannier [CDS] 25-Aug-2021