Letter to the Editor

APEX CO(3–2) observations of NGC 6822

¹ Astronomical Observatory, Ghent University, Krijgslaan 289 – S9, 9000 Ghent, Belgium e-mail: [Sven.DeRijcke;Pieter.Buyle]@UGent.be
² Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
³ ESO, Casilla 19001, Santiago 19, Chile
⁴ University of Nottingham, University Park, Nottingham NG7 2RD, UK

Received: 11 April 2006
Accepted: 1 June 2006

Abstract

We observed the ¹²CO() emission of the emission-line regions Hubble I, Hubble V, Hubble X, Holmberg 18, and the stellar emission-line object S28 in NGC 6822 with the ESO Atacama Pathfinder Experiment (APEX) 12 m telescope as part of its science verification. The very low system temperature of  K enabled us to achieve detections in 4 single pointings and in a high spatial resolution map of Hubble  V. We compare the spectra with Hi observations, obtained with the Australia Telescope Compact Array, of the same regions. In combination with previous multi-line CO observations, we perform a preliminary investigation of the physical conditions in Hubble  V using a simple LTE model. We estimate the mass of the Hubble V region and the H conversion factor. Also, we show that Hubble V is located very near the line-width versus size relation traced by the Milky Way and LMC molecular clouds.