2021-11-30

The fast telescope found the gas Accretion Flow over a very long distance in the nearby galaxy

By yqqlm yqqlm

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these cold gases can be observed through the 21cm spectral line of neutral hydrogen. However, the content of neutral hydrogen in the fiber structure is very low (about 0.1%), with a column density of 1016 cm-2, while the gas column density near the galaxy gradually increases, and it suddenly transits to the galaxy itself after reaching several times 1018 cm-2. Therefore, neutral hydrogen observation at column density sensitivity of 1018 cm-2 or lower is an important means to reveal cosmological accretion process. Astronomers try to detect rarefied gas accretion with lower surface density in the appearance of milky way type galaxies, but it is difficult to detect the dynamic evidence of accretion flow

recently, the National Observatory of the Chinese Academy of Sciences and its collaborators used the ultra-high sensitivity of fast telescope (500m aperture spherical radio telescope) to carry out in-depth imaging observation on the sky area of galaxy M106, the nearby galaxy Messier object, and obtained a high-sensitivity image with 5×1016 cm-2 column density for the first time. An ultra long-distance gas accretion stream is found outside M106 galaxy. The gas stream is 130 KPC (about 423000 light-years) and connects M106 and its satellite galaxy ngc4288. It shows that M106 galaxy can snatch gas from dwarf galaxies hundreds of thousands of light-years away to maintain its growth. This phenomenon is similar to the Magellanic flow from the Magellanic Nebula more than 200000 light-years away from the Milky way to the Milky way, but the accretion flow of M106 is longer, wider and more difficult to capture, which provides a typical case for exploring Galaxy gas accretion. There is no obvious trace of interaction around ngc4288 galaxy, the source of the accretion flow. Therefore, the reason for the formation of the accretion flow needs to be explained by more observation data and theoretical models

relevant research results were published on the Astrophysical Journal Letters. The research work was supported by the national key R & D plan and the National Natural Science Foundation of China

The fast telescope found the gas Accretion Flow over a very long distance in the nearby galaxy

contour map of integrated intensity of 21 cm spectral line of M106 accretion flow observed by fast (blue), with the background of integrated flow intensity distribution map of fast, The green contour shows the structure of M106 neutral hydrogen gas disk observed by WSRT interference array

385c4afa1f63507 - The fast telescope found the gas Accretion Flow over a very long distance in the nearby galaxy

sub channel intensity diagram of 21 cm spectral line of M106 accretion flow observed by fast