On the Structure of the Sagittarius Spiral Arm in the Inner Milky Way

Fuente: arXiv
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Auteurs principaux: Bian, S. B., Wu, Y. W., Xu, Y., Reid, M. J., Li, J. J., Zhang, B., Menten, K. M., Moscadelli, L., Brunthaler, A.
Format: Preprint
Publié: 2024
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author Bian, S. B.
Wu, Y. W.
Xu, Y.
Reid, M. J.
Li, J. J.
Zhang, B.
Menten, K. M.
Moscadelli, L.
Brunthaler, A.
author_facet Bian, S. B.
Wu, Y. W.
Xu, Y.
Reid, M. J.
Li, J. J.
Zhang, B.
Menten, K. M.
Moscadelli, L.
Brunthaler, A.
contents We report measurements of trigonometric parallax and proper motion for two 6.7 GHz methanol and two 22 GHz water masers located in the far portion of the Sagittarius spiral arm as part of the BeSSeL Survey. Distances for these sources are estimated from parallax measurements combined with 3-dimensional kinematic distances. The distances of G033.64$-$00.22, G035.57$-$00.03, G041.15$-$00.20, and G043.89$-$00.78 are $9.9\pm0.5$, $10.2\pm0.6$, $7.6\pm0.5$, and $7.5\pm0.3$ kpc, respectively. Based on these measurements, we suggest that the Sagittarius arm segment beyond about 8 kpc from the Sun in the first Galactic quadrant should be adjusted radially outward relative to previous models. This supports the suggestion of Xu et al. (2023) that the Sagittarius and Perseus spiral arms might merge in the first quadrant before spiraling inward to the far end of the Galactic bar.
format Preprint
id arxiv_https___arxiv_org_abs_2405_11439
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On the Structure of the Sagittarius Spiral Arm in the Inner Milky Way
Bian, S. B.
Wu, Y. W.
Xu, Y.
Reid, M. J.
Li, J. J.
Zhang, B.
Menten, K. M.
Moscadelli, L.
Brunthaler, A.
Astrophysics of Galaxies
We report measurements of trigonometric parallax and proper motion for two 6.7 GHz methanol and two 22 GHz water masers located in the far portion of the Sagittarius spiral arm as part of the BeSSeL Survey. Distances for these sources are estimated from parallax measurements combined with 3-dimensional kinematic distances. The distances of G033.64$-$00.22, G035.57$-$00.03, G041.15$-$00.20, and G043.89$-$00.78 are $9.9\pm0.5$, $10.2\pm0.6$, $7.6\pm0.5$, and $7.5\pm0.3$ kpc, respectively. Based on these measurements, we suggest that the Sagittarius arm segment beyond about 8 kpc from the Sun in the first Galactic quadrant should be adjusted radially outward relative to previous models. This supports the suggestion of Xu et al. (2023) that the Sagittarius and Perseus spiral arms might merge in the first quadrant before spiraling inward to the far end of the Galactic bar.
title On the Structure of the Sagittarius Spiral Arm in the Inner Milky Way
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2405.11439