SPIRE spectroscopy of the prototypical Orion Bar photodissociation region

E. Habart (1) , E. Dartois (1) , A. Abergel (1) , J.-P. Baluteau , D. Naylor , E. Polehampton , C. Joblin (2) , P. Ade , L. D. Anderson (3) , P. André (4) , H. Arab , J.-P. Bernard (1, 2) , K. Blagrave , Sylvain Bontemps (5, 6, 7, 8) , F. Boulanger (1) , M. Cohen , M. Compiegne , P. Cox , G. Davis (9) , R. Emery , T. Fulton , C. Gry (3) , M. Huang (10) , S. C. Jones , J. Kirk (11) , Guilaine Lagache (1) , T. Lim , S. Madden (12) , G. Makiwa , P. Martin (13) , M.-A. Miville-Deschênes (1) , S. Molinari (14) , H. Moseley , F. Motte (15, 16) , K. Okumura , D. Pinheiro Gonçalves , J. Rodon , D. Russeil (3) , P. Saraceno (14) , S. Sidher , L. Spencer , B. Swinyard , D. Ward-Thompson (11) , G. J. White (17) , Annie Zavagno (3, 18)

1 IAS - Institut d'astrophysique spatiale
2 CESR - Centre d'étude spatiale des rayonnements
3 LAM - Laboratoire d'Astrophysique de Marseille
4 LINA - Laboratoire d'Informatique de Nantes Atlantique
5 LAB - Laboratoire d'Astrophysique de Bordeaux [Pessac]
6 OASU - Observatoire aquitain des sciences de l'univers
7 UB - Université Sciences et Technologies - Bordeaux 1
8 L3AB - Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux
9 Department of Ecology and Evolutionary Biology [Princeton]
10 NAOC - National Astronomical Observatories [Beijing]
11 School of Physics and Astronomy [Cardiff]
12 DAPNIA - Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée
13 CITA
14 IFSI - Istituto di Fisica dello Spazio Interplanetario
15 AIM (UMR7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation
16 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers
17 Engineering Department
18 OAMP - Observatoire Astronomique de Marseille Provence

Aims: We present observations of the Orion Bar photodissociation region (PDR) obtained with the SPIRE instrument on-board Herschel. Methods: We obtained SPIRE Fourier-transform spectrometer (FTS) sparse sampled maps of the Orion bar. Results: The FTS wavelength coverage and sensitivity allow us to detect a wealth of rotational lines of CO (and its isotopologues), fine structure lines of C and N+, and emission lines from radicals and molecules such as CH+, CH, H2O or H2S. For species detected from the ground, our estimates of the column densities agree with previously published values. The comparison between 12CO and 13CO maps shows particularly the effects of optical depth and excitation in the molecular cloud. The distribution of the 12CO and 13CO lines with upper energy levels indicates the presence of warm (~100-150 K) CO. This warm CO component is a significant fraction of the total molecular gas, confirming previous ground based studies. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

Mots clés: infrared: ISM; ISM: lines and bands; ISM: molecules; evolution; submillimeter: ISM; ISM: general

Domaines: Astrophysique stellaire et solaire [astro-ph.SR]; Astrophysique stellaire et solaire [astro-ph.SR]

E. Habart, E. Dartois, A. Abergel, J.-P. Baluteau, D. Naylor, et al.. SPIRE spectroscopy of the prototypical Orion Bar photodissociation region. Astronomy and Astrophysics - A&A, 2010, 518, pp.L116. ⟨10.1051/0004-6361/201014654⟩. ⟨hal-00523010⟩