19th of January 2015 |
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2014 Science Highlights |
Detection of 36 GHz Class I methanol maser emission toward NGC 253 |
Ellingsen et al. (2014) have used the
Australia Telescope Compact Array (ATCA) to search for emission from the 36.2
GHz transition of methanol toward the center of the nearby starburst galaxy
NGC 253. Two regions of emission (red contours in the right panel) were
detected, offset from the nucleus along the same position angle as the inner
spiral arms. This was the first detection of a class I methanol maser beyond
the Mily Way. Image caption. - Left: Spitzer 24 micron image of NGC 253 (Dale et al. 2009). The blue box marks the region shown in the right-hand panel. Right: 36 GHz continuum emission (green contours at 20, 40, 60 and 80% of 95 mJy/beam) and 36.2 GHz methanol emission (red contours at 20, 40, 60 and 80% of 310 mJy/beam km/s). The dashed blue ellipse marks the half-maximum intensity of the central molecular zone of NGC 253 (Sakamoto et al. 2011). The background image is from Spitzer IRAC observations with blue, green and red from the 3.6, 4.5 and 8.0 micron bands respectively (Dale et al. 2009). The blue crosses mark the location of water masers detected by Henkel et al. (2004), the black stars mark supershells identified by Sakamoto et al. (2006) and Bolatto et al. (2013) and the black circles NH3 cores (Lebron et al. 2011). The cyan dashed line shows the size of the primary beam of the ATCA observations. |