H2CO and CH3OH maps of the Orion Bar photodissociation region

Leurini, S., Parise, Berengere, Schilke, P., Pety, J. and Rolffs, R. 2010. H2CO and CH3OH maps of the Orion Bar photodissociation region. Astronomy and Astrophysics 511 , A82. 10.1051/0004-6361/200912484

Preview

PDF - Published Version Download (1MB) | Preview

Abstract

Context. A previous analysis of methanol and formaldehyde towards the Orion Bar concludes that the two molecular species may trace different physical components, methanol the clumpy material, and formaldehyde the interclump medium. Aims. To verify this hypothesis, we performed multi-line mapping observations of the two molecules to study their spatial distributions. Methods. The observations were performed with the IRAM-30 m telescope at 218 and 241 GHz, with an angular resolution of . Additional data for H2CO from the Plateau de Bure array are also discussed. The data were analysed using an LVG approach. Results. Both molecules are detected in our single-dish data. Our data show that CH3OH peaks towards the clumps of the Bar, but its intensity decreases below the detection threshold in the interclump material. When averaging over a large region of the interclump medium, the strongest CH3OH line is detected with a peak intensity of ~0.06 K. Formaldehyde also peaks on the clumps, but it is also detected in the interclump gas. Conclusions. We verified that the weak intensity of CH3OH in the interclump medium is not caused by the different excitation conditions of the interclump material, but reflects a decrease in the column density of methanol. The abundance of CH3OH relative to H2CO decreases by at least one order of magnitude from the dense clumps to the interclump medium.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Physics and Astronomy
Subjects:	Q Science > QB Astronomy
Uncontrolled Keywords:	ISM: individual objects: Orion Bar; ISM: abundances; ISM: molecules; ISM: structure
Additional Information:	Pdf uploaded in accordance with publisher's policy at http://www.sherpa.ac.uk/romeo/issn/0004-6361/ (accessed 17/04/2014)
Publisher:	EDP Sciences
ISSN:	0004-6361
Date of First Compliant Deposit:	30 March 2016
Last Modified:	10 May 2023 04:51
URI:	https://orca.cardiff.ac.uk/id/eprint/52811

Citation Data

Cited 22 times in Scopus. View in Scopus. Powered By Scopus® Data

Actions (repository staff only)

Edit Item