2021-11-02

Can black holes devour stars and produce neutrinos? The new study cast doubt on astronomers

By yqqlm yqqlm

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at2019dsg is called tidal destruction event (TDE), which occurred in the same sky area generated by neutrinos only a few months ago – April 2019. Astronomers say the deformed violence must be the source of this powerful particle. But new research questions this claim

Can black holes devour stars and produce neutrinos? The new study cast doubt on astronomers

in a study published in the Journal of astrophysics, researchers from the astrophysics center of Harvard University, the Smithsonian Institution and Northwestern University put forward a large number of new radio observations and data about at2019dsg, So that the research team can calculate the energy emitted by the event. The results show that the energy produced by at2019dsg is far less than that required by neutrinos; In fact, the energy it emits is quite “ordinary”, the research team concluded

black holes are “chaotic diners”

although this may seem counterintuitive, black holes do not always swallow everything. “Black holes are not like vacuum cleaners,” said Yvette zenders, a postdoctoral fellow at the center for Astrophysics who led the research. He explained that when a star is too close to a black hole, gravity begins to elongate or deform the star. Eventually, the elongated material rotates around the black hole and heats up, forming a flash in the sky that astronomers can find millions of light-years away

“however, when there is too much material, the black hole cannot eat it smoothly all at once,” said Kate Alexander, a postdoctoral fellow at Northwestern University and co-author of the research report. He called the black hole “chaotic food”. “In this process, some gas will be ejected again — just like when a baby eats, some food will eventually fall on the floor or wall.”

these “leftovers” are thrown back into space in the form of outflow or jet — if powerful enough, they can theoretically produce a subatomic particle called neutrino

using the super large array in New Mexico and the Atacama large millimeter / submillimeter array (ALMA) in Chile, the research team can observe at2019dsg about 750 million light-years away in more than 500 days after the black hole began to devour stars. Extensive radio observations made at2019dsg the most fully studied TDE so far, and it was found that the radio brightness peaked about 200 days after the event

according to these data, the total energy outflow is equivalent to the energy radiated by the sun in 30 million years. Although this sounds impressive, the powerful neutrinos discovered on October 1, 2019 need a source with 1000 times more energy

Cendes added: “if this neutrino comes from at2019dsg in some way, this raises a question. Why don’t we find neutrinos related to supernovae at this distance or closer? They are more common and have the same energy velocity.”

the team concluded that neutrinos are unlikely to come from this specific TDE. However, if it does, astronomers are far from understanding TDE and how they emit neutrinos