Curious layman Posted August 15, 2019 Posted August 15, 2019 (edited) Milky way's black hole just flared, growing 75 times as bright for a few hours Abstract... Quote Even though the black hole at the center of the Milky Way is a monster, it's still rather quiet. Called Sagittarius A, it's about 4.6 million times more massive than the sun. Usually, it's a brooding behemoth. But scientists observing Sgr. A with the Keck Telescope just observed it's brightness blooming to over 75 times normal for a few hours. four images from the paper. Over about a 2 hour period. The flaring is not visible in optical light, it's all happening in the near-infrared...Astronomers have been watching Sgr. A for 20 years, and though the black hole does have some variability in its output, this flaring event is like nothing astronomers have observed before. This peak was over twice as bright as the previous peak flux level....The team saw Sgr. A flaring at 75 times normal for a two-hour period on May 13th. At first, astronomer Tuan Do thought that they were seeing a star called SO-2 rather than Sgr. A. SO-2 is one of a group of stars called S-stars that orbits the black hole closely.....The question is, what made Sgr. A flare like this?.....It's likely that something disrupted the black hole's usually quiet neighbourhood, and there are at least a couple of possibilities. The first is not actually a disruption, but an inaccuracy in the statistical models used to u understand the black hole... The second possibility is where things get interesting: Something has changed in the black hole's neighbourhood. The group of stars that orbit close to Sgr. A are called S stars. SO-2 made it's closest approach about a year ago. The previously mentioned star SO-2 is a prime candidate. It's one of two stars that approach very closely to Sgr. A in an elliptical orbit...Its possible that SO-2's close approach disrupted the way material flows into Sgr. A. But astronomers aren't certain, SO-2 is not a very large star and it see s unlikely to cause this type of disruption Another possibility is a gas cloud. Back in 2002 astronomers saw what they thought might be a hydrogen gas cloud approaching the center of Sgr. A. By 2012 astronomers were more certain..and it was named G2. They measured the temperature of the cloud at 10,000 degrees Kelvin...in 2013 it would travel close enough to the black hole that the tidal forces would rip it apart. In the final analysis, this flaring may just be the natural result of a variable flow of material into Sgr. A which is expected to be lumpy......more at link https://phys.org/news/2019-08-milky-black-hole-flared-bright.html Edited August 15, 2019 by Curious layman 1
Janus Posted August 16, 2019 Posted August 16, 2019 And while we are now just seeing this, it occurred 27,000 years ago; during the Upper Paleolithic, and while we were in the Last Glacial Period. Woolly mammoth still roamed the mainland. 1
J.C.MacSwell Posted August 17, 2019 Posted August 17, 2019 11 hours ago, Janus said: And while we are now just seeing this, it occurred 27,000 years ago; during the Upper Paleolithic, and while we were in the Last Glacial Period. Woolly mammoth still roamed the mainland. Light sure takes it's good ol' time!
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