He proposed that BAL variation might be an effective tool in penetrating outflows. In this work, he advanced this approach by thinking about both the amplitude and the phase of the function which explains the response of ionized gas under radiation. They acquired the kinetic details regarding quasar outflows, and found the velocity at a scale of tens of parsecs for the very first time, which far exceeded that forecasted by the standard accretion disk wind design.
Quasar illustration. Credit: NOIRLab/NSF/AURA/ J. da Silva
Dr. HE Zhicheng and his coworkers from the University of Science and Technology of China (USTC) of the Chinese Academy of Sciences developed a new way to determine the physical properties of stellar ionized gas, and found the velocity of quasar outflows at the scale of 10s of parsecs for the very first time. Their paper was released on Science Advances.
According to contemporary theories on galactic development and development, the system of Active Galactic Nuclei (AGN) feedback suggests that the gigantic black hole at a galactic center modulates its advancement by blowing ionized gas, namely the quasar outflow, avoiding a prospective oversized growth of great void. The outflow, which transfers matter and energy to host galaxies, works as one of the primary ways of AGN feedback.
Little was understood about the outflow of active galaxies, for a crucial element, the scale of outflows was generally deduced from spectroscopic blueshifted adsorption lines (BAL). The acquired outcomes were not reliable enough due to their heavy reliance on designs.
Dr. HE developed a new technique based upon his previous research studies. He proposed that BAL variation could be a powerful tool in probing outflows. In this work, he advanced this method by thinking about both the amplitude and the stage of the function which describes the action of ionized gas under radiation. They obtained the kinetic information regarding quasar outflows, and discovered the velocity at a scale of tens of parsecs for the first time, which far went beyond that forecasted by the conventional accretion disk wind design.
Interstellar dust could be a significant factor for the velocity, as proposed by Dr. HE and other fellow scholars, because the cross area in between dust and accretion disk ultraviolet radiation far surpasses that of Thomson scattering of free electrons. Their computations showed this hypothesis, and the speculated scale of outflow origin matched that of the dust ring, securely supporting their theory.
The findings showed that dust did play an essential role in the linkage between accretion disk radiation and interstellar media, and the considerable impact of outflows on host galaxies was shown. The findings were likewise consistent with the evidence of outflows suppression on star formations, which was discovered recently by Dr. HE and his partners.
Reference: “Evidence for quasar quick outflows being accelerated at the scale of tens of parsecs” by Zhicheng He, Guilin Liu, Tinggui Wang, Guobin Mou, Richard Green, Weihao Bian, Huiyuan Wang, Luis C. Ho, Mouyuan Sun, Lu Shen, Nahum Arav, Chen Chen, Qingwen Wu, Hengxiao Guo, Zesen Lin, Junyao Li and Weimin Yi, 11 February 2022, Science Advances.DOI: 10.1126/ sciadv.abk3291.