Mookerjea, B., Sandell, G., Veena, V. S., Gusten, R., Riquelme, D., Wiesemeyer, H., Wyrowski, F. and Mertens, M. (2021). Distribution of ionized, atomic, and PDR gas around S 1 in rho Ophiuchus. Astron. Astrophys., 648. LES ULIS CEDEX A: EDP SCIENCES S A. ISSN 1432-0746

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Abstract

The early B star S 1 in the rho Ophiuchus cloud excites an H II region and illuminates a large egg-shaped photon-dominated (PDR) cavity. The PDR is restricted to the west and southwest by the dense molecular rho Oph A ridge, expanding more freely into the diffuse low-density cloud to the northeast. We analyzed new SOFIA GREAT, GMRT, and APEX data together with archival data from Herschel/PACS and JCMT/HARP to study the properties of the photo-irradiated ionized and neutral gas in this region. The tracers include [C II] at 158 mu m, [O I] at 63 and 145 mu m, the J = 6-5 transitions of CO and (CO)-C-13, HCO+ (4-3), the radio continuum at 610 and 1420 MHz, and H I at 21 cm. The PDR emission is strongly redshifted to the southeast of the nebula, and primarily blueshifted on the northwestern side. The [C II] and [O I]63 spectra are strongly self-absorbed over most of the PDR. By using the optically thin counterparts, [C-13 II] and [O I]145 respectively, we conclude that the self-absorption is dominated by the warm (>80 K) foreground PDR gas and not by the surrounding cold molecular cloud. We estimate the column densities of C+ and O-0 of the PDR to be similar to 3 x 10(18) and similar to 2 x 10(19) cm(-2), respectively. Comparison of stellar far-ultraviolet flux and reprocessed infrared radiation suggest enhanced clumpiness of the gas to the northwest. Analysis of the emission from the PDR gas suggests the presence of at least three density components consisting of high-density (10(6) cm(-3)) clumps, medium-density (10(4) cm(-3)) and diffuse (10(3) cm(-3)) interclump medium. The medium-density component primarily contributes to the thermal pressure of the PDR gas, which is in pressure equilibrium with the molecular cloud to the west. Emission velocities in the region suggest that the PDR is tilted and somewhat warped, with the southeastern side of the cavity being denser at the front and the northwestern side being denser at the rear.

Item Type: Journal Article
Creators:
CreatorsEmailORCIDORCID Put Code
Mookerjea, B.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Sandell, G.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Veena, V. S.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Gusten, R.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Riquelme, D.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Wiesemeyer, H.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Wyrowski, F.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Mertens, M.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
URN: urn:nbn:de:hbz:38-588807
DOI: 10.1051/0004-6361/202040217
Journal or Publication Title: Astron. Astrophys.
Volume: 648
Date: 2021
Publisher: EDP SCIENCES S A
Place of Publication: LES ULIS CEDEX A
ISSN: 1432-0746
Language: English
Faculty: Unspecified
Divisions: Unspecified
Subjects: no entry
Uncontrolled Keywords:
KeywordsLanguage
STRUCTURE LINE EMISSION; MOLECULAR CLOUD; PHOTODISSOCIATION REGIONS; COLLISIONAL EXCITATION; C II; SUBMILLIMETER; PROTOSTARS; CLUSTERS; CORES; DUSTMultiple languages
Astronomy & AstrophysicsMultiple languages
URI: http://kups.ub.uni-koeln.de/id/eprint/58880

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