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| Formato: | Preprint |
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2024
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| Acceso en línea: | https://arxiv.org/abs/2401.02312 |
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| author | Oyama, Tomoaki Nagayama, Takumi Yamauchi, Aya Sakai, Daisuke Imai, Hiroshi Honma, Mareki Asakura, Yu Hada, Kazuhiro Hagiwara, Yoshiaki Hirota, Tomoya Jike, Takaaki Kono, Yusuke Suzuki, Syunsaku Kobayashi, Hideyuki Kawaguchi, Noriyuki |
| author_facet | Oyama, Tomoaki Nagayama, Takumi Yamauchi, Aya Sakai, Daisuke Imai, Hiroshi Honma, Mareki Asakura, Yu Hada, Kazuhiro Hagiwara, Yoshiaki Hirota, Tomoya Jike, Takaaki Kono, Yusuke Suzuki, Syunsaku Kobayashi, Hideyuki Kawaguchi, Noriyuki |
| contents | We successfully measured the trigonometric parallax of Sagittarius A* (Sgr A*) to be $117\pm17$ micro-arcseconds ($μ$as) using the VLBI Exploration of Radio Astrometry (VERA) with the newly developed broad-band signal-processing system named OCTAVE-DAS. The measured parallax corresponds to a Galactocentric distance at the Sun of $R_0 = 8.5^{+1.5}_{-1.1}$ kpc. By combining the astrometric results with VERA and the Very Long Baseline Array (VLBA) over a monitoring period of 25 years, the proper motion of Sgr A* is obtained to be $(μ_α, μ_δ) = (-3.133\pm0.003, -5.575\pm0.005)$ mas yr$^{-1}$ in equatorial coordinates, corresponding to $(μ_l, μ_b) = (-6.391\pm0.005, -0.230\pm0.004)$ mas yr$^{-1}$ in Galactic coordinates. This gives an angular orbital velocity of the Sun of $Ω_\odot = 30.30 \pm 0.02$ km s$^{-1}$ kpc$^{-1}$. We find upper limits to the core wander, $Δθ< 0.20$ mas (1.6 AU), peculiar motion, $Δμ< 0.10$ mas yr$^{-1}$ (3.7 km s$^{-1}$), and acceleration, $a < 2.6$ $μ$as yr$^{-2}$ (0.10 km s$^{-1}$ yr$^{-1}$) for Sgr A*. Thus, we obtained upper mass limits of $\approx$ 3 $\times$ 10$^{4}$$M_{\odot}$ and $\approx$ 3 $\times$ 10$^{3}$$M_{\odot}$ for the supposed intermediate-mass black holes at 0.1 and 0.01 pc from the Galactic center, respectively. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2401_02312 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Trigonometric parallax and proper motion of Sagittarius A* measured by VERA using the new broad-band back-end system OCTAVE-DAS Oyama, Tomoaki Nagayama, Takumi Yamauchi, Aya Sakai, Daisuke Imai, Hiroshi Honma, Mareki Asakura, Yu Hada, Kazuhiro Hagiwara, Yoshiaki Hirota, Tomoya Jike, Takaaki Kono, Yusuke Suzuki, Syunsaku Kobayashi, Hideyuki Kawaguchi, Noriyuki Astrophysics of Galaxies Instrumentation and Methods for Astrophysics We successfully measured the trigonometric parallax of Sagittarius A* (Sgr A*) to be $117\pm17$ micro-arcseconds ($μ$as) using the VLBI Exploration of Radio Astrometry (VERA) with the newly developed broad-band signal-processing system named OCTAVE-DAS. The measured parallax corresponds to a Galactocentric distance at the Sun of $R_0 = 8.5^{+1.5}_{-1.1}$ kpc. By combining the astrometric results with VERA and the Very Long Baseline Array (VLBA) over a monitoring period of 25 years, the proper motion of Sgr A* is obtained to be $(μ_α, μ_δ) = (-3.133\pm0.003, -5.575\pm0.005)$ mas yr$^{-1}$ in equatorial coordinates, corresponding to $(μ_l, μ_b) = (-6.391\pm0.005, -0.230\pm0.004)$ mas yr$^{-1}$ in Galactic coordinates. This gives an angular orbital velocity of the Sun of $Ω_\odot = 30.30 \pm 0.02$ km s$^{-1}$ kpc$^{-1}$. We find upper limits to the core wander, $Δθ< 0.20$ mas (1.6 AU), peculiar motion, $Δμ< 0.10$ mas yr$^{-1}$ (3.7 km s$^{-1}$), and acceleration, $a < 2.6$ $μ$as yr$^{-2}$ (0.10 km s$^{-1}$ yr$^{-1}$) for Sgr A*. Thus, we obtained upper mass limits of $\approx$ 3 $\times$ 10$^{4}$$M_{\odot}$ and $\approx$ 3 $\times$ 10$^{3}$$M_{\odot}$ for the supposed intermediate-mass black holes at 0.1 and 0.01 pc from the Galactic center, respectively. |
| title | Trigonometric parallax and proper motion of Sagittarius A* measured by VERA using the new broad-band back-end system OCTAVE-DAS |
| topic | Astrophysics of Galaxies Instrumentation and Methods for Astrophysics |
| url | https://arxiv.org/abs/2401.02312 |