A TRIGONOMETRIC PARALLAX OF Sgr B2

By M. J. Reid, K. Menten, Xing-wu Zheng, A. Brunthaler, Ye Xu. 2009

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We have measured the positions of H2O masers in Sgr B2, a massive star-forming region in the Galactic center, relative to an extragalactic radio source with the Very Long Baseline Array. The positions measured at 12 epochs over a time span of one year yield the trigonometric parallax of Sgr B2 and hence a distance to the Galactic center of R0 = 7.9+0.8−0.7 kpc. The proper motion of Sgr B2 relative to Sgr A* suggests that Sgr B2 is ≈0.13 kpc nearer than the Galactic center, assuming a low-eccentricity Galactic orbit.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/67d83584ef6a2f4906407b732c04f23a0b70c85c

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Citations in the corpus

THE WISE CATALOG OF GALACTIC H ii REGIONS (2013, methodology): “…et al. 2007; (19) Moellenbrock et al. 2009; (20) Moscadelli et al. 2009; (21) Niinuma et al. 2011; (22) Oh et al. 2010; (23) Reid et al. 2009a; (24) Reid et al. 2009c; (25) Rygl et al. 2010; (26) Rygl et al. 2012; (27) Sanna et al. 2009; (28) Sanna et al. 2012; (29) Sato et al. 2008; (30) Sato…”
Fundamental Parameters of the Milky Way Galaxy Based on VLBI Astrometry (2012, methodology): “If Vˇ = 5.25 km s 1 is adopted to this relation, the star-forming regions lag behind the Galactic rotation by 14 km s 1, confirming the earlier suggestion by Reid et al. (2009b).”
Molecular gas kinematics within the central 250 pc of the Milky Way (2016, background): “So far, the only published maser proper motion values in the Galactic centre have been determined for the water masers in Sgr B2 (µl,µb = 2.3±1.0,−1.4±1.0 mas yr−1; Reid et al. 2009).”
Spectral imaging of the Central Molecular Zone in multiple 3-mm molecular lines (2011, methodology): “We use the distance to the Galactic Centre of 8.0 kpc (Reid et al. 2009), so 1 arcmin corresponds to 2.3 pc.”
The Australia Telescope Compact Array Broadband Backend (CABB): Description & First Results ⋆ (2011, methodology): “McGrath et al. (2004) show a similar spectrum at 0.66 kms−1 velocity resolution, while Reid et al. (2009) determined the trigonometric parallax of SgrB2 by measuring the H2O maser positions with the Very Large Baseline Array (VLBA) over one year.”
The observed spiral structure of the Milky Way (2014, methodology): “A flat rotation curve (Reid et al. 2009b, 2014; Brunthaler et al. 2011) and the rotation curve of Brand & Blitz (1993, hereafter BB93) are adopted in calculating the kinematic distances.”
What controls star formation in the central 500 pc of the Galaxy (2013, methodology): “5 kpc, which is consistent with Reid et al. 2009).”
Trigonometric Parallaxes of High-mass Star-forming Regions: Our View of the Milky Way (2019, background): “A trigonometric parallax measurement of water masers from Sgr B2, a massive star-forming region within »100 pc of the Galactic center, indicates = R 7.9 0.8 kpc0 (Reid et al. 2009c).”
Detection of the Schwarzschild precession in the orbit of the star S2 near the Galactic centre massive black hole (2020, methodology): “This supports the interpretation that the compact radio source is coincident with the mass (Reid & Brunthaler 2004; Reid et al. 2009; Reid & Brunthaler 2020).”
The Galaxy in Context: Structural, Kinematic, and Integrated Properties (2016, methodology): “VLBI astrometry has provided accurate parallaxes and PMs for over 100 OH, SiO, and methanol masers in high-mass star-formation regions (HMSFRs) in the Galactic disk (Honma et al. 2007, 2012; Reid et al. 2009a, 2014; Sato et al. 2010).”
DISCOVERY OF A SUPERLUMINAL Fe K ECHO AT THE GALACTIC CENTER: THE GLORIOUS PAST OF Sgr A* PRESERVED BY MOLECULAR CLOUDS (2010, background): “Its projected distance is about 100 pc East of Sgr A* and a recent parallax measurement places it about 130 pc in front of the plane of Sgr A* (Reid et al. 2009).”
Complex organic molecules in the interstellar medium: IRAM 30 m line survey of Sagittarius B2(N) and (M) (2013, background): “It is the most massive star-forming region in our Galaxy, at a projected distance of∼ 100 pc from the Galactic center, which is located at 7.9±0.8 kpc from the Sun (Reid et al. 2009).”
The dynamical evolution of molecular clouds near the Galactic Centre - I. Orbital structure and evolutionary timeline (2014, background): “Given that the proper motion of Sgr B2 could be measured using a∼ 1 yr baseline (Reid et al. 2009), the proper motion of the far-side clouds should be detectable with ease, provided that suitable masers can be identified.”
AN IMPROVED DISTANCE AND MASS ESTIMATE FOR SGR A* FROM A MULTISTAR ORBIT ANALYSIS (2016, background): “VLBI measurements of the trigonometric parallax of H2O masers in the star forming region Sgr B2 give a value of 7.9±0.8 kpc (Reid et al. 2009), while dynamical modelling of the nuclear star cluster gives a statistical parallax distance to the Galactic Center of 8.27±0.13 kpc (Chatzopoulos et al.…”
TRIGONOMETRIC PARALLAXES OF HIGH MASS STAR FORMING REGIONS: THE STRUCTURE AND KINEMATICS OF THE MILKY WAY (2014, methodology): “The Bovy et al. (2009) re-analysis of our preliminary data employed a different ap- proach than that of Reid et al. (2009b).”
The mass distribution and gravitational potential of the Milky Way (2016, methodology): “They have therefore been used by numerous authors to constrain the properties of the Milky Way (e.g.,Reid et al. 2009a; McMillan & Binney 2010; Bovy et al. 2009; Bobylev & Bajkova 2013; Reid et al. 2014, Paper I).”
The Bar and Spiral Structure Legacy (BeSSeL) Survey: Mapping the Milky Way with VLBI Astrometry† (2011, methodology): “A description that takes into account these two effects and gives (in general) more accurate kinematic distances, and a more realistic distance uncertainty estimate is also presented in Reid et al. (2009b).”