On the 7th, it was learned from the University of Science and Technology of China that Professor Wang Tinggui's research team in the Department of Astronomy has recently conducted multi band high-frequency monitoring of the black hole tidal tearing star event AT2023lli. They found that the most significant "bulge" feature appeared before the peak of the optical ultraviolet light change curve, and found that X-rays exhibited "intermittent" radiation characteristics. These new evolutionary features provide important clues for revealing the physical processes of such events. The relevant research results were recently published online in the international astronomical journal Astrophysical Journal Letters. When a star accidentally moves near a massive black hole at the center of a galaxy, it is torn apart and accreted by the powerful tidal force of the black hole. This process will generate multi band electromagnetic flares, lasting for several months to several years. This phenomenon is called black hole tidal tearing stellar events (TDE). After the discovery of TDE, researchers need to use ground and space telescopes to observe it in a timely manner, obtain photometric and spectral evolution information, and then infer the main physical processes and black hole parameters that occur. Previously discovered TDE exhibits a relatively smooth trend of rapid increase and slow decrease in its optical curves, but AT2023lli is an outlier. The optical monitoring results show that there is a strong "bulge" in the early stage of light change rise. The "bulge" lasted for nearly a month, with a time interval of up to two months between it and the main peak - this is currently the most obvious and longest time interval "bulge" in TDE. The research team speculated through the analysis of multi band optical variation curves that such a peculiar optical "bulge" is likely caused by the impact of fragmented stars torn apart under the general relativity effect. In addition, it is also possible for binary systems to be torn apart by black holes, with two tearing processes producing "bulges" and main peaks, respectively. The researchers provided an explanation for the phenomenon of X-rays being delayed by ultraviolet optical radiation and exhibiting "intermittent" radiation in the first image. The research team believes that in addition to producing bulges, debris flow impacts also generate outflow projectiles. These substances obscure the inner region of the accretion disk and absorb soft X-ray photons, which are then converted into ultraviolet optical radiation through reprocessing. Due to the uneven distribution of shielding material, X-rays "leak out", and at the same time, due to the motion of material around the black hole, it leads to "intermittent" characteristics. (Lai Xin She)
Edit： Responsible editor：
Source：
Special statement: if the pictures and texts reproduced or quoted on this site infringe your legitimate rights and interests, please contact this site, and this site will correct and delete them in time. For copyright issues and website cooperation, please contact through outlook new era email：lwxsd@liaowanghn.com
Sci-Tech
Recommended Reading Change it 
Home
