[ad_1]
The distance between our Solar System and Sagittarius A *, the 4-million-solar-mass black hole at the center of our Milky Way, is about 25,800 light-years, about 1,900 light-years closer than the previous estimate, according to a data analysis. of the Japanese VLBI (Very Long Baseline Interferometer) VERA (VLBI Exploration of Radio Astrometry) project.
Map of the position and speed of the Milky Way; arrows show position and velocity data for 224 objects used to model the Galaxy; the solid black lines show the positions of the spiral arms of the Galaxy; the colors indicate groups of objects belonging to the same arm. Image credit: NAOJ.
“Since the Earth is inside the Milky Way, we can’t step back and see what our Galaxy looks like from the outside,” said Dr. Tomoya Hirota, an astronomer with the Mizusawa VLBI Observatory at the Astronomical Observatory. Japan National and Department of Astronomical Sciences at SOKENDAI and his colleagues from the VERA Collaboration.
“Astrometry, accurate measurement of the positions and movements of objects, is a fundamental tool for understanding the overall structure of the galaxy and our place in it.”
“VERA was started by the National Astronomical Observatory of Japan in the 2000s,” they added.
“The project was designed to focus on VLBI astrometric observations to reveal 3D velocity and spatial structures in the Milky Way.”
“It involved four 20m radio telescopes in Japan: at Mizusawa, Iriki, Ogasawara and Ishigaki-jima stations.”
Using data from the first VERA astrometric catalog, astronomers modeled the structure of the Milky Way to estimate fundamental parameters such as the distance to the galactic center and the speed of the Sun around it.
“Our results suggest that the center of the Galaxy, and the supermassive black hole that resides there, is 25,800 light-years from Earth,” they said.
“This is closer than the official value of 27,700 light years adopted by the International Astronomical Union in 1985”.
“The velocity component of the map indicates that the Sun is traveling at 227 km / s as it orbits the galactic center. This is faster than the official value of 220 km / s. “
VERA researchers now plan to observe more objects, especially those close to Sagittarius A *, to better characterize the structure and movement of the Milky Way.
“As part of these efforts, VERA will participate in the East Asian VLBI Network (EAVN) consisting of radio telescopes located in Japan, South Korea and China,” they said.
“By increasing the number of telescopes and the maximum distance between telescopes, EAVN can achieve even greater accuracy.”
The VERA catalog was recently published in Publications of the Astronomical Society of Japan.
_____
Tomoya Hirota et al. (VERA collaboration). 2020. The first catalog of VERA astrometry. Publications of the Astronomical Society of Japan 72 (4): 50; doi: 10.1093 / pasj / psaa018
Source link
