Universität zu Köln

Leurini, S., Wyrowski, F., Wiesemeyer, H., Gusdorf, A., Guesten, R., Menten, K. M., Gerin, M., Levrier, F., Huebers, H. W., Jacobs, K., Ricken, O. and Richter, H. (2015). Spectroscopically resolved far-IR observations of the massive star-forming region G5.89-0.39. Astron. Astrophys., 584. LES ULIS CEDEX A: EDP SCIENCES S A. ISSN 1432-0746

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Abstract

Context. The fine-structure line of atomic oxygen at 63 mu m ([OI](63) (mu m)) is an important diagnostic tool in different fields of astrophysics: it is for example predicted to be the main coolant in several environments of star-forming regions (SFRs). However, our knowledge of this line relies on observations with low spectral resolution, and the real contribution of each component (photon-dominated region, jet) in the complex environment of SFRs to its total flux is poorly understood. Aims. We investigate the contribution of jet and photon-dominated region emission, and of absorption to the [OI](63 mu m) line towards the hot gas around the ultra-compact HII region G5.89-0.39 and study the far-IR line luminosity of the source in different velocity regimes through spectroscopically resolved spectra of atomic oxygen, [CII], CO, OH, and H2O. Methods. We mapped G5.89-0.39 in [OI](63 mu m) and in CO(16-15) with the GREAT receiver onboard SOFIA. We also observed the central position of the source in the ground-state OH (2)Pi(3/2), J = 5/2 -> J = 3/2 triplet and in the excited OH (2)Pi(1/2), J = 3/2 -> J = 1/2 triplets with SOFIA. These data were complemented with APEX CO(6-5) and CO(7-6) maps and with Herschel/HIFI maps and single-pointing observations in lines of [CII], H2O, and HF. Results. The [OI] spectra in G5.89-0.39 are severely contaminated by absorptions from the source envelope and from different clouds along the line of sight. Emission is detected only at high velocities, and it is clearly associated with the compact north-south outflows traced by extremely high-velocity emission in low-J CO lines. The mass-loss rate and the energetics of the jet system derived from the [OI](63 mu m) line agree well with previous estimates from CO, thus suggesting that the molecular outflows in G5.89-0.39 are driven by the jet system seen in [OI]. The far-IR line luminosity of G5.89-0.39 is dominated by [OI] at high-velocities; the second coolant in this velocity regime is CO, while [CII], OH and H2O are minor contributors to the total cooling in the outflowing gas. Finally, we derive abundances of different molecules in the outflow: water has low abundances relative to H-2 of 10(-8) - 10(-6), and OH of 10(-8). Interestingly, we find an abundance of HF to H-2 of 10(-8), comparable with measurements in diffuse gas. Conclusions. Our study shows the importance of spectroscopically resolved observations of the [OI](63 mu m) line for using this transition as diagnostic of star-forming regions. While this was not possible until now, the GREAT receiver onboard SOFIA has recently opened the possibility of detailed studies of the [OI](63 mu m) line to investigate the potential of the transition for probing different environments.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Leurini, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Wyrowski, F. UNSPECIFIED UNSPECIFIED UNSPECIFIED Wiesemeyer, H. UNSPECIFIED UNSPECIFIED UNSPECIFIED Gusdorf, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Guesten, R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Menten, K. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Gerin, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Levrier, F. UNSPECIFIED UNSPECIFIED UNSPECIFIED Huebers, H. W. UNSPECIFIED UNSPECIFIED UNSPECIFIED Jacobs, K. UNSPECIFIED UNSPECIFIED UNSPECIFIED Ricken, O. UNSPECIFIED UNSPECIFIED UNSPECIFIED Richter, H. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-384976
DOI:	10.1051/0004-6361/201526466
Journal or Publication Title:	Astron. Astrophys.
Volume:	584
Date:	2015
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:	Keywords Language FINE-STRUCTURE LINES; 63 MU-M; YOUNG STELLAR OBJECTS; HYDROGEN-FLUORIDE; MOLECULAR CLOUDS; HERSCHEL/HIFI OBSERVATIONS; INFRARED SPECTROSCOPY; HETERODYNE INSTRUMENT; INTERSTELLAR-MEDIUM; COLOGNE DATABASE Multiple languages Astronomy & Astrophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/38497