An international team of astronomers used the Sardinia Radio Telescope (Sardinia Radio Telescope), Italy, to create a detailed image of the Andromeda radio wave at a microwave frequency of 6.6 GHz. The Andromeda Galaxy (M31) is about 2.5 million light-years away from the Earth. It is the largest galaxy in the local galaxy group, including the Milky Way, the Triangulum Galaxy (M33), M32, M110 and several other smaller galaxies. The redshift is z=-0.001, and a negative value indicates that it is positively approaching the Milky Way.
The Andromeda Galaxy is a very good laboratory for us. Because of its size and distance, we can further study and confirm the physical mechanisms and characteristics that have only been studied in the Milky Way. The new image of the Sardinia Radio Telescope can study the structure of the Andromeda galaxy in more detail, know yourself and the enemy, and have a clearer understanding of what is happening in the Milky Way, just like looking at yourself from the outside.
Never before has such a large sky map of the Andromeda galaxy been drawn in the 1~22GHz microwave band. The galaxy radiation in the range is very weak, so it is difficult to see the structure. However, the characteristics of this frequency band are crucial for further understanding of the physical processes occurring inside Andromeda. Astronomers confirmed about 100 point source catalogs, including Andromeda background stars, galaxies and other objects, and confirmed low-emission sources that have never been detected at a frequency of 6.6GHz, and calculated the total star formation rate within a radius of 49,000 light-years It is 0.19 solar masses per year, which is consistent with the literature results. The researchers stated that they can determine the radiation caused by the thermal process related to the early formation of new stars, as well as the radio signals attributed to the non-thermal mechanism of cosmic rays. The research results were published in the journal Astronomy & Astrophysics.
▲ The Andromeda Galaxy taken by the Sardinia Radio Telescope. This is an image after averaging the 6.6GHz bandwidth. (Source: Fatigoni et al.)
(This article is reprinted with permission from the Taipei Planetarium; the source of the first image: Flickr/Sergio.Poppi CC BY 2.0)
