Astrometry and spatio-kinematics of H{sub 2}O masers in the massive star-forming region NGC 6334I(North) with VERA

Journal Article · Tue Apr 01 04:00:00 EDT 2014 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/784/2/114· OSTI ID:22357270

Chibueze, James O. ^[1]; Omodaka, Toshihiro; Handa, Toshihiro; Imai, Hiroshi ^[2]; Kurayama, Tomoharu ^[3]; Nagayama, Takumi; Sunada, Kazuyoshi; Hirota, Tomoya; Honma, Mareki ^[4]; Nakano, Makoto ^[5]

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1. East Asian ALMA Regional Center, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)
2. Department of Physics and Astronomy, Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065 (Japan)
3. Center for Fundamental Education, Teikyo University of Science, 2525 Yatsusawa, Uenohara, Yamanashi 409-0193 (Japan)
4. Mizusawa VLBI Observatory, National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)
5. Faculty of Education and Welfare Science, Oita University, Oita 870-1192 (Japan)

We measured the trigonometric parallax of an H{sub 2}O maser source associated with the massive star-forming region NGC 6334I(North), hereafter as NGC 6334I(N), with the VLBI Exploration of Radio Astrometry. The derived annual parallax is 0.789 ± 0.161 mas, corresponding to a distance of 1.26{sub −0.21}{sup +0.33} kpc. Using the new distance, we recalculated the physical parameters (masses and luminosities) of the dust continuum cores in the region, and the revised parameters are only ∼50% of their originally reported values. We also traced 23 relative proper motions of the H{sub 2}O masers associated with SMA1 (central millimeter source in the region) between epochs, which exhibit an average amplitude of maser proper motion of ∼2.03 mas yr{sup –1} (∼12.22 km s{sup –1}), tracing a bipolar outflow. The bipolar outflow structure extends through ∼600 mas (∼720 AU), with a dynamical timescale of ∼295 yr. Using an expanding flow model, we derived the most plausible dynamical center of the outflow, pointing to SMA1b (1.3 cm and 7 mm continuum source) as the outflow driving source. Based on our results and other existing parallax results, we derive the pitch angles of the Sagittarius arm as 6.°2 ± 5.°4 along the Galactic longitude range of ∼0.°7 – ∼40.°1 assuming a perfect logarithmic spiral. We derived the peculiar motion of NGC 6334I(N) to be –4 ± 1 km s{sup –1} toward the Galactic center, 8 ± 2 km s{sup –1} in the direction of the Galactic rotation, and 25 ± 2 km s{sup –1} toward the Galactic north pole.

• OSTI ID: 22357270
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 784; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
AMPLITUDES
DISTANCE
DUSTS
EXPLORATION
FLOW MODELS
GALACTIC EVOLUTION
GALAXY NUCLEI
INCLINATION
LUMINOSITY
MASERS
MASS
PROPER MOTION
ROTATION
STARS
WATER