2018/10/15 by Xinwu Cao, Tinggui Wang, Cao, Xinwu +1
Physics and Astronomy · #Astrophysical Phenomena and Observations #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #High Energy Astrophysical Phenomena (astro-ph.HE) #Pulsars and Gravitational Waves Research
paper · pdf · doi:10.48550/arxiv.1810.06358
openalex publication_date 2018/10/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The temperature remains nearly constant while blackbody emission in UV/optical bands declines more than one order of magnitude in some tidal disruption events (TDEs). The physics behind it is still a mystery. A strong outflow can be driven by the radiation of the disc with super-Eddington luminosity. The disc emission drops rapidly to sub-Eddington luminosity, and the gas may fall back to the black hole. An optically thick shell is formed with gas temperature \la 5× 104K due to line absorption, which is irradiated by the disc, and is re-emitting UV/optical photons. As the shell moves inwards, the gas at the inner surface of the shell is completely ionized at a certain temperature ∼ 104-5× 104K, which makes the gas optically thin for line absorption, and it therefore falls from the shell. This line absorbing layer acts as temperature regulator, i.e., the gas in the inner shell surface is removed to reduce the shell mass while the temperature is rising, and the decrease of the shell mass (gravity) decelerates the shell till a new balance is achieved between the radiation force and the gravity. This failed-outflow model can naturally explain the declining UV/optical blackbody radiation with constant temperature.