Astron. Astrophys. 359, 1139-1146 (2000)

Multiwavelength observations of N 66 in the SMC: unveiling photodissociation interfaces and star formation ^*

M. Rubio ¹, A. Contursi ^2,3,4, J. Lequeux ⁴, R. Probst ⁵, R. Barbá ⁶, F. Boulanger ⁷, D. Cesarsky ^7,9 and R. Maoli <sup>8,4

1</sup> Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile
² IPAC, Caltech, MS 100-22, Pasadena, CA 91125, USA
³ SAp/DAPNIA/DSM, CEA-Saclay, 91191 Gif sur Yvette CEDEX, France
⁴ DEMIRM, Observatoire de Paris, 61 Avenue de l'Observatoire, 75014 Paris, France
⁵ Cerro Tololo Inter-American Observatory, NOAO, Casilla 603, La Serena, Chile
⁶ Facultad de Ciencias Astronómicas y Geofisícas, Universidad Nacional de La Plata, Paseo del Bosque s/n, 1900 La Plata, Argentina
⁷ Institut d'Astrophysique Spatiale, Bat. 121, Université Paris XI, 91450 Orsay CEDEX, France
⁸ Institut d'Astrophysique, 98 bis Boulevard Arago, 75014 Paris, France
⁹ Max-Planck-Institut für Extraterrestrische Physik, P.O. Box 1603, 85740 Garching, Germany

Received 31 January 2000 / Accepted 26 April 2000

Abstract

We present new observations of the major star-forming region N 66 in the Small Magellanic Cloud and of its surroundings, which add to those presented in Contursi et al. (2000, Paper I). High-sensitivity CO observations allowed the detection of molecular gas associated with the H II  region, for which a high-resolution image in [O III ] 5007 is presented. We also present images in the v(1-0) S(1) line of H₂ at 2.12 µm and in the adjacent continuum. This material reveals an interesting photodissociation region. We show that the molecular gas that has not yet been photodissociated by the UV radiation of the stars is in hot, dense clumps with a very small surface filling factor. We discovered several embedded stars or stellar associations, and suggest that three successive stellar generations have already taken place in less than 3 million years.

Key words: ISM: individual objects: N 66(SMC) ISM: H ii regions ISM: dust, extinction galaxies: Magellanic Clouds infrared: ISM: continuum infrared: ISM: lines and bands

* Based on observations with the Swedish-ESO Submillimeter Telescope (SEST) at the European Southern Observatory (ESO), La Silla, Chile, at the Cerro Tololo Interamerican Observatory, National Optical Observatories, operated by AURA under contract with the National Science Foundation, at the Las Campanas Observatory and with ISO, an ESA project with instruments funded by ESA member states (especially the PI countries: France, Germany, the Netherlands and the United Kingdom) and with the participation of ISAS and NASA.

Send offprint requests to: M. Rubio (mrubio@das.uchile.cl)

SIMBAD Objects

Contents

• 1. Introduction
• 2. CO observations and data reduction
• 3. Near-infrared observations and data reduction
• 4. Molecular gas and photodissociation regions
• 5. Conclusions
• Acknowledgements
• References

© European Southern Observatory (ESO) 2000

Online publication: July 13, 2000
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