National Radio Astronomy Observatory | 2017 May 23
[c][imghover=https://public.nrao.edu/wp-content/uplo ... 7df01d.jpg]https://public.nrao.edu/wp-content/uplo ... 7df01b.jpg[/imghover]2015/1989 VLA radio image (orange) of Cygnus A, overlaid on Hubble image.Pointing the Very Large Array (VLA) at a famous galaxy for the first time in two decades, a team of astronomers got a big surprise, finding that a bright new object had appeared near the galaxy’s core. The object, the scientists concluded, is either a very rare type of supernova explosion or, more likely, an outburst from a second supermassive black hole closely orbiting the galaxy’s primary, central supermassive black hole.
Credit: Perley, et al., NRAO/AUI/NSF, NASA[/c][hr][/hr]
The astronomers observed Cygnus A, a well-known and often-studied galaxy discovered by radio-astronomy pioneer Grote Reber in 1939. The radio discovery was matched to a visible-light image in 1951, and the galaxy, some 800 million light-years from Earth, was an early target of the VLA after its completion in the early 1980s. Detailed images from the VLA published in 1984 produced major advances in scientists’ understanding of the superfast “jets” of subatomic particles propelled into intergalactic space by the gravitational energy of supermassive black holes at the cores of galaxies. ...
The scientists then observed Cygnus A with the Very Long Baseline Array (VLBA) in November of 2016, clearly detecting the new object. A faint infrared object also is seen at the same location in Hubble Space Telescope and Keck observations, originally made between 1994 and 2002. The infrared astronomers, from Lawrence Livermore National Laboratory, had attributed the object to a dense group of stars, but the dramatic radio brightening is forcing a new analysis. ...
While the new object definitely is separate from Cygnus A’s central supermassive black hole, by about 1500 light-years, it has many of the characteristics of a supermassive black hole that is rapidly feeding on surrounding material. ...
Discovery of a Luminous Radio Transient 460 pc from the Central Supermassive Black Hole in Cygnus A - Daniel A. Perley et al
- arXiv.org > astro-ph > arXiv:1705.07901 > 22 May 2017