We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
East Asian VLBI Network astrometry toward the extreme outer Galaxy: Kinematic distance with the proper motion of G034.84−00.95.
- Authors
Sakai, Nobuyuki; Zhang, Bo; Xu, Shuangjing; Sakai, Daisuke; Tamura, Yoshiaki; Jike, Takaaki; Jung, Taehyun; Oh, Chungsik; Kim, Jeong-Sook; Kawaguchi, Noriyuki; Imai, Hiroshi; Jiang, Wu; Cui, Lang; Kim, Soon-Wook; Jiang, Pengfei; Kurayama, Tomoharu; Lee, Jeong Ae; Hachisuka, Kazuya; Jung, Dong-Kyu; Xia, Bo
- Abstract
We aim to reveal the structure and kinematics of the Outer Scutum–Centaurus (OSC) arm located on the far side of the Milky Way through very long baseline interferometry (VLBI) astrometry using KaVA, which is composed of KVN (the Korean VLBI Network) and VERA (VLBI Exploration of Radio Astrometry). We report the proper motion of a 22 GHz H2O maser source, which is associated with the star-forming region G034.84−00.95, to be (μαcos δ, μδ) = (−1.61 ± 0.18, −4.29 ± 0.16) mas yr−1 in equatorial coordinates (J2000.0). We estimate the 2D kinematic distance to the source to be 18.6 ± 1.0 kpc, which is derived from the variance weighted average of kinematic distances with local standard of rest velocity and the galactic-longitude component of the measured proper motion. Our result places the source in the OSC arm and implies that G034.84−00.95 is moving away from the Galactic plane with a vertical velocity of −38 ± 16 km s−1. Since the H i supershell GS033+06−49 is located at a kinematic distance roughly equal to that of G034.84−00.95, it is expected that gas circulation occurs between the outer Galactic disk around G034.84−00.95 with a Galactocentric distance of |$12.8^{+1.0}_{-0.9}\:$| kpc and the halo. We evaluate possible origins of the fast vertical motion of G034.84−00.95, which are (1) supernova explosions and (2) cloud collisions with the Galactic disk. However, neither of these possibilities are matched with the results of VLBI astrometry or the spatial distributions of H ii regions and H i gas.
- Subjects
VERY long baseline interferometry; ASTROMETRY; VERTICAL motion; GALAXY mergers; MILKY Way
- Publication
Publications of the Astronomical Society of Japan, 2023, Vol 75, Issue 1, p208
- ISSN
0004-6264
- Publication type
Article
- DOI
10.1093/pasj/psac102