by A bright quasar, powered by a supermassive black hole, is blasting radiation that pushes the gas clouds around it to generate winds that reach speeds of around 36 million miles per hour (58 million kilometers per hour). Oh, and the quasar is almost as old as the universe itself.
The discovery, made by a team of scientists led by University of Wisconsin-Madison astronomers, shows the role that supermassive black holes feeding at the core of “active galactic nuclei,” or “AGNs,” can play in a broader sculpture. galaxies around them.
The researchers arrived at their findings using eight years of data on the quasar SBS 1408+544, located 13 billion light-years away in the Bootes constellation. These data were collected by the Sloan Digital Sky Survey (SDSS) Black Hole Echo Mapping Project. The light from SBS 1408+544 has been traveling to Earth for 13 billion years; that’s almost as long as the 13.8 billion year old universe.
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Although supermassive black holes with masses equal to millions, or sometimes billions of suns, are thought to be at the core of most galaxies, not all of these quasars are powering up. Quasar black holes are surrounded by matter in a cloud of spreading vortices called “accretion disks” that gradually feed them matter.
The massive gravitational influence of the central supermassive black hole of a quasar causes frictional and tidal forces to stir the material of the accretion disk, causing it to burn intensely. In addition, material that does not enter the supermassive black hole is sent to the cosmic titan’s poles by powerful magnetic fields, where it is accelerated to near-light speeds and blasted out as high-impact jets. These two jets are accompanied by electromagnetic radiation emissions from each black hole pole.
Not only does this radiation make some quasars brighter than the combined light of all the stars in the galaxies around them, but this light also shapes those galaxies and gives astronomers a useful measure of how black holes affect galaxies in general. measurement.
“That matter [accretion] the disc is always falling into the black hole, and the friction of that drag and pull pushes the disc up and makes it very, very hot and very bright,” said team leader and University of Wisconsin astronomy professor -Madison Catherine Grier in her statement, “The quasars are really luminous, and because there is a wide range of temperatures from the interior to the far parts of the disk, their emission covers almost the entire electromagnetic spectrum.”
The bright light from this particular quasar allowed Grier and colleagues to trace winds of gaseous carbon. This was done by measuring gaps in the broad spectrum of electromagnetic radiation emitted by the quasar, which indicated that light was being absorbed by carbon atoms.
The team found that every time they measured this absorption spectrum over 130 observations of SBS 1408+544, there was a shift from the correct position of the carbon absorption “shadow”. This increased over time as radiation from the quasar pushed away material around it. This matter created the massive black hole winds that reached speeds of up to 36 million miles per hour (58 million kilometers per hour), which is about 45,000 times higher than the speed of sound.
“That change tells us that the gas is moving fast, and faster all the time,” said team co-leader and University of Wisconsin-Madison astronomy graduate Robert Wheatley. “The wind is accelerating because it is being pushed by radiation blasted out of the accretion disk.”
Scientists suspect they’ve seen accelerating supermassive black hole winds before, but this is the first time the observation has been backed up by hard evidence. Such cosmic winds are of interest to astronomers because the gas they move around is the building blocks of stars. That means, if black hole winds are powerful enough, they can cut off star formation, thereby “killing” their host galaxies. They can also strip supermassive central black holes of fuel, ending their days as quasar machines.
That could turn an active galaxy into a quiescent one like the Milky Way, which has a “sleeping giant” black hole at its heart as well as forming stars at a very slow rate. Sagittarius A* (Sgr A*), our black hole, is surrounded by so little matter that its diet of gas and dust is equivalent to a person eating a grain of rice every million years. Alternatively, the winds from supermassive black holes could compress gas rather than push it away, triggering new rounds of star formation in their host galaxies.
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Black hole winds like the kind the teams see could travel beyond the edges of their galaxies, affecting neighboring galaxies and, eventually, the supermassive black holes at the core of those galaxies.
“Supermassive black holes are big, but they are really tiny compared to their galaxies,” Grier said. “That doesn’t mean they can’t ‘talk’ to each other, and this is a way of talking to the other that we’ll have to account for when we model the effects of these black holes.”
The team’s research was published in June in the Astrophysical Journal.
