Letter to the Editor

Millimeter dust emission from an SMC cold molecular cloud

¹ Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago e-mail: mrubio@das.uchile.cl
² Institut d'Astrophysique Spatiale, Université Paris-Sud, Bât. 121, 91405 Orsay Cedex, France
³ European Southern Observatory, Casilla 19001, Santiago 19, Chile
⁴ Max-Planck-Institute fur Extraterrestische Physik (MPE), Posfach 1312, 85741 Garching, Germany

Received: 13 April 2004
Accepted: 25 July 2004

Abstract

We presented SIMBA 1.2 mm continuum observations of SMCB1-1 an SMC molecular cloud known to be distant from massive ionizing stars. The gas mass derived from the SIMBA flux is a factor of ~10 higher than the virial mass previously reported from CO observations. We propose an interpretation where the virial mass underestimates the total mass because the CO emission comes from dense clumps which do not trace the full cloud area and velocity distribution. This work sets an important question for the understanding of star formation in low metallicity gas. Do CO observations grossly underestimate the amount of dense self gravitating clouds where stars can form?