Tracing major structures of the inner Galaxy with 6.7-GHz methanol masers

¹ CSIRO Astronomy and Space Science, Australia Telescope National Facility, Australia
² Jodrell Bank Centre for Astrophysics, University of Manchester, UK
³ School of Physics, University of New South Wales, Australia
⁴ School of Mathematics and Physics, University of Tasmania, Australia
⁵ INAF/IFSI, Roma, Italy
⁶ Centre for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, UK

^a e-mail: james.green@csiro.au

Abstract

Through analysis of correlations within the longitude-velocity distribution of 6.7-GHz methanol masers, we identify density enhancements indicative of large-scale regions of enhanced star formation. In the context of the inner structure of our Galaxy these are interpreted as the starting points of the spiral arms and the interaction of the long Galactic bar with the 3–kpc arms. Signatures of a continuous 3–kpc arm structure are seen including a prominent tangent at –22° Galactic longitude.