Astronomers have discovered a number of interesting physical phenomena around Sagittarius A, believed to be a supermassive black hole at the center of the Milky Way, according tomedia CNET. Astronomers observed the star “dancing” around it, catalogating its infrared radiation, and discovering a strange unknown object orbiting the “cosmic monster.” And now they think this huge black hole is “blinking” at us.
In a new study published in the Astrophysical Journal in April, a team of Japanese researchers used the Atacama Large Millimeter Wave/Submillimeter Wave Array (ALMA) in Chile to study Sgr A. ALMA is a 66-disc antenna array capable of observing the universe with millimeter and submillimeter wave light. Researchers have previously detected Sgr A, and found a black hole about 4 million times larger than our sun flashing in this wavelength of light. The astronomy team at Keio University tracked the study and focused ALMA on the black hole for a week and a half, trying to detect much smaller changes in the black hole’s flicker.
“This time, with ALMA, we obtained high-quality data on the changes in radio wave intensity of Sgr A, lasting 10 days for 70 minutes a day,” Yuhei Iwata, an astrophysicist at Keio University and the study’s first author, said in a press release. The observations were made in 2017, and when the team sifted through the data, they saw Sgr A spinbes flashing regularly.
“This emission may be related to some strange phenomena that occur near supermassive black holes,” said Tomoharu Oka, co-author of the study. They suspect that this activity may be related to the black hole’s accretion disk.
Black holes are basically invisible to telescopes. Black holes do not emit any detectable light because their gravity is very special. Astronomers, however, can detect hot gas around a black hole, which is trapped by its gravitational pull. The team believes that the flashing signal is related to the innermost edge of the Sgr A-s accretion disk. This edge is very close to the black hole, which is rotating gas and debris at a near-light rate. In this process, hot spots appear, emitting millimeter and submillimeter light, which is the signal they detect. As hot spots move toward us in space, flickers are amplified.
This activity may tell us more about how black holes behave and how the gas around the center of the black hole accumulates. But if astronomers try to image Sgr A, as they did last year, it could be problematic. “The faster you move, the harder it is to photograph the object,” Oka said. “