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arXiv · 1611.00930

Parallaxes of 6.7-GHz Methanol Masers towards the G305.2 High-Mass Star Formation Region

V Krishnan·S P Ellingsen·M J Reid·H E Bignall·J McCallum·C J Phillips·C Reynolds·J Stevens
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Abstract

We have made measurements to determine the parallax and proper motion of the three 6.7-GHz methanol masers G305.200$+$0.019, G305.202$+$0.208 and G305.208$+$0.206. The combined parallax is found to be 0.25$\pm $0.05 mas, corresponding to a distance of 4.1$^{+1.2}_{-0.7}$ kpc. This places the G305.2 star formation region in the Carina-Sagittarius spiral arm. The inclusion of G305.2 increases the Galactic azimuth range of the sources in this arm by 40$^\circ $ from Sato et al., allowing us to determine the pitch angle of this spiral with greater confidence to be $ψ= 19.0 \pm 2.6^\circ $. The first VLBI spot maps of the 6.7-GHz methanol masers towards these sources show that they have simple linear and ring-like structures, consistent with emission expected from classII methanol masers in general.

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V Krishnan, S P Ellingsen, M J Reid, H E Bignall, J McCallum, C J Phillips, C Reynolds, J Stevens. 2016-11-03. Parallaxes of 6.7-GHz Methanol Masers towards the G305.2 High-Mass Star Formation Region. https://doi.org/10.1093/mnras%2Fstw2850

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