February 8, 2024
BEIJING – Using spectrum data collected by the Large-Sky Area Multi-Object Fiber Spectroscopic Telescope, along with other studies and observations, Chinese astronomers have constructed the most detailed rotation curve ever created of the Andromeda galaxy (M31), calculating the mass of the galaxy. approximately 1.14 billion times that of the Sun.
The study, carried out by researchers from Yunnan University and other institutions in the country, was recently published in the journal Monthly Notices of the Royal Astronomical Society.
At a distance of approximately 2.5 million light years from Earth, the Andromeda Galaxy is the closest large spiral galaxy to the Milky Way and serves as an ideal astrophysical laboratory for exploring the formation and evolution of galaxies.
“However, due to the galaxy’s considerable distance from Earth, it has been difficult for astronomers to identify the celestial bodies in it, and the lack of information about the motion of these celestial bodies made it extremely difficult to establish with certainty. precision the rotation curve of the galaxy. ”said Chen Bingqiu, professor at Yunnan University and corresponding co-author of the study paper, cited by Science and Technology Daily.
In this study, the research team collected radial velocity measurements from 13,679 celestial bodies in the Andromeda galaxy and determined the rotation curve within 407,600 light-years of its center, achieving an accuracy of 5 to 20 percent.
It showed that the rotation curve remains relatively constant at about 220 kilometers per second within its galactic disk, gradually decreasing outward to about 170 kilometers per second in its outer halo.
And based on the rotation curve, the research team built a mass model for the Andromeda galaxy that consists of three components and provides the mass distribution of the galaxy.
According to Chen, the study offers a new understanding of the mass distribution of the Andromeda galaxy and, by extension, of spiral galaxies in general, which has significant importance for further understanding of the dynamical structure, formation and formation. evolution of spiral galaxies.