EDP Sciences
Free access
Volume 496, Number 3, March IV 2009
Page(s) 677 - 682
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361/200810365
Published online 18 February 2009
A&A 496, 677-682 (2009)
DOI: 10.1051/0004-6361/200810365

The molecular gas content of blue dwarf galaxies

A collapsing detached molecular system in He 2–10?
L. Vanzi1, 2, F. Combes3, M. Rubio4, and D. Kunth5

1  Departamento de Ingeniera Electrica, Pontificia Universidad Catolica de Chile, Av. Vicuña Mackenna 4860, Santiago, Chile
    e-mail: lvanzi@ing.puc.cl
2  European Southern Observatory, Alonso de Cordoba 3107, Vitacura, Santiago, Chile
3  Observatoire de Paris, 61 Av. de l'Observatoire, 75014 Paris, France
4  Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago, Chile
5  Institut dAstrophysique de Paris, 98bis Bd Arago, 75014 Paris, France

Received 10 June 2008 / Accepted 20 January 2009

We present new observations of a sample of blue dwarf galaxies in the lines of CO(3–2) and HCN(4–3). The observations were obtained with the 12 m APEX telescope located at an altitude of 5100 m in Chajnantor (ALMA site). We detected CO(3–2) emission in seven of nine observed galaxies in our sample. In two galaxies, NGC 5253 and He 2–10, we mapped the central $20\arcsec\times20\arcsec$ in the CO(3–2) emission line. In He 2–10, we detected an extended component of molecular gas to the north-east of the main body of the galaxy. Comparing our data with previous HI and CO observations, we speculate that the presence of this detached cloud of molecular gas is produced by the merger already known in He 2–10, and could lead to the formation of a small tidal dwarf galaxy. The HCN(4–3) line was observed in NGC 5253 and He 2–10 only, but not detected.

Key words: galaxies: dwarf -- galaxies: ISM -- galaxies: starburst

© ESO 2009