[Scientific Research Progress] The scientific research team of Shanghai Observatory has made new progress in the nature of high -red shift galaxies and the field of universe recreation

Recently, the Shanghai Academy of Sciences SKA (square kilometers, Square Kilometre Array, abbreviated as SKA) radio cosmopolitics group using the Hubble Space Telescope (HST) Deep Gravity Mirror Starbone Group Observation Hubble Frontier FROELDS (HFF) project The measurement data of the Gallem Lighting Function of the Gahong Red Movement (Z ~ 6) reveals the contribution of the electrolael ion provided by the extremely small quality stars in the first generation of celestial bodies to the reunion of the universe, and further predicts these high -red shifts. The impact of dark galaxy on the neutral hydrogen signal during the removal period. Related research results were published on August 30, 2022 at the Royal Capital Monthly (MNRAS).

The early universe experienced the formation of the dark period and large -scale structure. Among them, the first -generation emitting celestial bodies surrounded by space medium (mainly consisting of neutral hydrogen) were gradually appeared. These space media. This process has formed an increased and diffusion area, which is called "the universe dawn and reconstruction". The 21CM signal generated by the transition of neutral hydrogen atoms is one of the most important means of the cosmic structure and galaxy formation of the "universe dawn and reconstruction" period, and one of the primary scientific goals of SKA.

Some studies believe that in the high -red shift universe, due to the equivalent effect of radiation feedback, the efficiency of galaxy star formation in small quality and dark halo may be suppressed, thereby reducing the number of dark galaxies in the early universe [1]. Some foreign teams analyzed the observation data of the HFF strong mirror galaxy group, and found that the optical function of the high -red -shift galaxy turned off at the extremely dark end, which proved the existence of the effect from observation [2].

The Shanghai Observatory's SKA radio cosmology group further studied the effects of the total orthoscope provided by the stars in the re -electrical period. By establishing a semi -analysis model in the stars in the galaxy, combined with the dark material halo quality function, the theoretical simulation can be simulated to obtain the evolution of the galaxy and light over time. Based on this, it can obtain different moments in the universe. Total amount of ion and ultraviolet photons. The use of these physical quantities can be quantitatively estimated at a certain at a time and the temperature of the intercourse media. These properties will determine the 21cm bright temperature of the early cosmic galaxy media that astronomers can observe today [3]. "In the early universe, the large -quality dark halo and galaxy have not grown fully. In fact, the photon that drives the reconstruction process mainly comes from small quality galaxies." Zhang Zekang, a graduate student of Shanghai Observatory, explained that "the nature of the study of these galaxies understands us. The process is very critical. " Researcher of Shaanxi Huanyuan from the Shanghai Observatory SKA radio cosmology group said: "The decrease in the purpose of the dark star coefficient will significantly reduce the total amount of orthoscope, and delay the occurrence of the entire recycling process and the growth of cosmic power structure." (Figure 1)

As the world's largest telescope mirror array, one of the primary goals is to detect 21cm signals from the reconstruction period. Different from the total signal of the whole day, SKA-LOW captures the space statistical information of the 21cm bright temperature at a red shift, thereby obtaining the scale distribution of the ionized hydrogen area. Scientific researchers at the same time estimate the effect of HFF optical function observation on the 21cm power spectrum with red movement of 6. The results show that the SKA-LOW low-frequency array column has sufficient sensitivity to identify the impact at a larger scale. The team's researchers look forward to the recent launch and use of James Weibu Space Space Telescope (JWST) to accurately measure the farther and darker galaxy light function, and provide further verification of the effect -SKA in the radio power band for the interstate media media Observations are complementary to the optical and infrared direct observations of James Wabo Space Telescope (JWST) and the upcoming China Space Station Telescope (CSSST). The veil.

Figure 1, 21cm total power signal simulation throughout the day. The black solid line is the benchmark model, and the gray solid line is the limit on the 21CM signal based on the HFF optical function. The figure shows the HFF -based optical function observation. The restrictions on the total power signal from the 21cm full -day power signal from the dawn of the universe and the removal period. Reduce about 30mk.

references:

[1] Yue B., Ferrara A., XU Y., 2016, Mnras, 463, 1968

[2] ATEK H., Richard J., KNEIB J.-P., SCHAERER D., 2018, Mnras, 479, 5184

[3] Mirocha J., Ferlanetto S. R., Sun G., 2017, Mnras, 464, 1365

Please see the original reading of the article link.

Scientific contact:

Shaanxi Huanyuan, Shanghai Academy of Sciences Shanghai Observatory, [email protected]

Zhang Zekang, Shanghai Academy of Sciences Shanghai Observatory, [email protected]

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