| dc.creator |
Pety, Jérôme |
|
| dc.creator |
Teyssier, D. |
|
| dc.creator |
Fosse, David |
|
| dc.creator |
Gerin, M. |
|
| dc.creator |
Roueff, E. |
|
| dc.creator |
Abergel, A. |
|
| dc.creator |
Habart, E. |
|
| dc.creator |
Cernicharo, José |
|
| dc.date |
2007-12-28T11:19:17Z |
|
| dc.date |
2007-12-28T11:19:17Z |
|
| dc.date |
2005-01-17 |
|
| dc.date.accessioned |
2017-01-31T00:59:34Z |
|
| dc.date.available |
2017-01-31T00:59:34Z |
|
| dc.identifier |
arXiv:astro-ph/0501339v1 |
|
| dc.identifier |
Astronomy & Astrophysics 435, 885-899 (2005) |
|
| dc.identifier |
1432-0746 |
|
| dc.identifier |
http://hdl.handle.net/10261/2631 |
|
| dc.identifier |
10.1051/0004-6361:20041170 |
|
| dc.identifier.uri |
http://dspace.mediu.edu.my:8181/xmlui/handle/10261/2631 |
|
| dc.description |
In press in Astronomy & Astrophysics. Uses aa LaTeX macros. |
|
| dc.description |
We present maps at high spatial and spectral resolution in emission lines of C2H, c-C3H2, C4H, 12CO and C18O of the edge of the Horsehead nebula obtained with the Plateau de Bure Interferometer (PdBI). The edge of the Horsehead nebula is a one-dimensional Photo-Dissociation Region (PDR) viewed almost edge-on. All hydrocarbons are detected at high signal-to-noise ratio in the PDR where intense emission is seen both in the H2 ro-vibrational lines and in the PAH mid-infrared bands. C18O peaks farther away from the cloud edge. Our observations demonstrate that C2H, cC3H2 and C4H are present in UV-irradiated molecular gas, with abundances nearly as high as in dense, well shielded molecular cores. PDR models (i) need a large density gradient at the PDR edge to correctly reproduce the offset between the hydrocarbons and H2 peaks and (ii) fail to reproduce the hydrocarbon abundances. We propose that a new formation path of carbon chains, in addition to gas phase chemistry, should be considered in PDRs: because of intense UV-irradiation, large aromatic molecules and small carbon grains may fragment and feed the interstellar medium with small carbon clusters and molecules in significant amount. |
|
| dc.description |
We are grateful to the IRAM staff at
Plateau de Bure, Grenoble and Pico Veleta, Granada for competent help with the observations and data reduction. IRAM is supported by the INSU/CNRS (France), MPG (Germany) and IGN (Spain). We acknowledge funding by the French CNRS/PCMI program. |
|
| dc.description |
Peer reviewed |
|
| dc.format |
1049977 bytes |
|
| dc.format |
application/pdf |
|
| dc.language |
eng |
|
| dc.publisher |
EDP Sciences |
|
| dc.relation |
Preprint |
|
| dc.rights |
openAccess |
|
| dc.subject |
ISM clouds |
|
| dc.subject |
Molecules |
|
| dc.subject |
Individual object (Horsehead nebula) |
|
| dc.subject |
Radio lines: ISM |
|
| dc.title |
Are PAHs precursors of small hydrocarbons in Photo-Dissociation Regions? The Horsehead case |
|
| dc.type |
Pre-print |
|