@article{6009addb717945538570bffb24a70ef0,
title = "Inverse MultiView. II. Microarcsecond Trigonometric Parallaxes for Southern Hemisphere 6.7GHz Methanol Masers G232.62+00.99 and G323.74–00.26",
abstract = "We present the first results from the Southern Hemisphere Parallax Interferometric Radio Astrometry Legacy Survey: 10 μas accurate parallaxes and proper motions for two Southern Hemisphere 6.7 GHz methanol masers obtained using the inverse MultiView calibration method. Using an array of radio telescopes in Australia and New Zealand, we measured trigonometric parallaxes and proper motions for the masers associated with the star formation region G232.62+00.99 of π = 0.610 ± 0.011 mas, μx = −2.266 ± 0.021 mas yr−1, and μy = 2.249 ± 0.049 mas yr−1, which implies its distance to be d = 1.637 ± 0.029 kpc. These measurements represent an improvement in accuracy by more than a factor of 3 over the previous measurements obtained through Very Long Baseline Array observations of the 12 GHz methanol masers associated with this region. We also measure the trigonometric parallax and proper motion for G323.74–00.26 as π = 0.364 ± 0.009 mas, μx = −3.239 ± 0.025 mas yr−1, and μy = − 3.976 ± 0.039 mas yr−1, which implies a distance of d = 2.747 ± 0.068 kpc. These are the most accurate measurements of trigonometric parallax obtained for 6.7 GHz class II methanol masers to date. We confirm that G232.62+00.99 is in the Local Arm and find that G323.74–00.26 is in the Scutum–Centaurus arm. We also investigate the structure and internal dynamics of both masers.",
keywords = "Radio astrometry (1337), Unified Astronomy Thesaurus concepts: Astrophysical masers (103), Very long baseline interferometry (1769)",
author = "Hyland, {L. J.} and Reid, {M. J.} and G. Orosz and Ellingsen, {S. P.} and Weston, {S. D.} and J. Kumar and R. Dodson and Rioja, {M. J.} and Hankey, {W. J.} and Yates-Jones, {P. M.} and T. Natusch and S. Gulyaev and Menten, {K. M.} and A. Brunthaler",
note = "Funding Information: This research was supported by the Australian Research Council (ARC) Discovery grant No. DP180101061. We want to thank Mr. Brett Reid and Mrs. Bev Benson for maintaining and organizing the University of Tasmania radio telescopes. We acknowledge the Jawoyn, Paredarerme, and Wiriangu peoples as the traditional owners of the land situating the Katherine, Hobart, and Ceduna telescopes, respectively. The Warkworth 30 m radio telescope is funded and operated by the Auckland University of Technology; we would like to thank Mr. Lewis Woodburn for the maintenance and management of this facility to enable its involvement in this project. This research has made use of NASA{\textquoteright}s Astrophysics Data System Abstract Service. This research made use of MaserDB.net, an online database of astrophysical masers (Ladeyschikov et al. ). This research made use of Astropy, a community-developed core Python package for astronomy (Astropy Collaboration et al. , ). Publisher Copyright: {\textcopyright} 2023 Institute of Physics Publishing. All rights reserved.",
year = "2023",
month = aug,
day = "1",
doi = "10.3847/1538-4357/acdbc5",
language = "English",
volume = "953",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing",
number = "1",
}