Absolute positions of 6.7-GHz methanol masers

¹ Max-Planck-Institute fr Radioastronomie, Auf dem Hägel 69, 53121 Bonn, Germany
² Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, PR China e-mail: xuye@pmo.ac.cn
³ Australia Telescope National Facility CSIRO, PO Box 76, Epping, NSW 1710, Australia
⁴ Astro Space Centre, Profsouznaya st. 84/32, 117997 Moscow, Russia
⁵ Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai, 20030, PR China
⁶ Ural State University, Ekaterinburg, 620083, Russia

Received: 23 March 2009
Accepted: 24 July 2009

Abstract

The ATCA, MERLIN and VLA interferometers were used to measure the absolute positions of 35 6.7-GHz methanol masers to subarcsecond or higher accuracy. Our measurements represent essential preparatory data for Very Long Baseline Interferometry, which can provide accurate parallax and proper motion determinations of the star-forming regions harboring the masers. Our data also allow associations to be established with infrared sources at different wavelengths. Our findings support the view that the 6.7 GHz masers are associated with the earliest phases of high-mass star formation.