A Search for H2 Outflow Signatures from Massive Star Formation Regions Containing Linearly Distributed Methanol Masers

Abstract

I present here the summary of results from a survey by De Buizer (2003) searching for outflows using near-infrared imaging. Targets were massive young stellar objects associated with methanol masers in linear distributions. Presently, it is a widely held belief that these methanol masers are found in (and delineate) circumstellar accretion disks around massive stars. A way to test the disk hypothesis is to search for outflow signatures perpendicular to the methanol maser distributions. The main objective of the survey was to obtain wide-field near-infrared images of the sites of linearly distributed methanol masers using a narrow-band 2.12 micron filter which is centered on the H2 v=1-0 S(1) line. This line is a shock diagnostic that has been shown to successfully trace CO outflows from young stellar objects. Twenty-eight sources in total were imaged with eighteen sources displaying H2 emission. Of these, only TWO sources showed emission found to be dominantly perpendicular to the methanol maser distribution. These results seriously question the hypothesis that methanol masers exist in circumstellar disks.