An active galactic nucleus in the center of ESO 253-G003, an active galaxy over 570 million light-years away in Pictor’s southern constellation, will explode around every 114 days, according to a paper published in the Astrophysical Iris.
Supermassive black hole siphons gas off a large orbiting star. Image credit: NASA Goddard Space Flight Center / Chris Smith, USRA & GESTAR.
ASASSN-14ko was first detected on November 14, 2014, by the All-Sky Automated Survey for Supernovae (ASAS-SN).
At the time, astronomers thought the event in ESO 253-G003 was more like a supernova, a one-time star-destroying event.
“ASASSN-14ko is our current best example of occasional variability in an active galaxy, despite decades of other claims, as its flame time is fairly consistent across the six years of data, ”said Dr. Jeremy Schnittman, an NASA astronaut. Goddard Space Flight Center not involved in the investigation.
“The result of this is a real revolution of force of multi-wave observation astronomy.”
“We believe that a massive black hole at the center of the galaxy is creating the explosions as it partially eats a giant orbiting star,” said lead author Anna Payne, an astronaut at the University of Hawai’i in Mānoa.
Looking at the ESO 253-3 light loop, or the graph of brightness over time, Payne and colleagues noticed a series of 17 flames, all separated by about 114 days. Each flame reaches its maximum brightness in about five days, then goes down steadily.
The astronauts predicted that the galaxy would light up again on May 17, 2020, so they coordinated a joint observation with ground-based and space-based facilities, including dimensions. multi-wave with NASA’s Neil Gehrels Swift Observatory. ASASSN-14ko started right on schedule.
They have predicted and seen subsequent flames on September 7 and December 20, 2020.
They also used data from NASA’s Transiting Exoplanet Survey Satellite (TESS) to create a precise timeline of a flame that began on November 7, 2018, tracking its appearance, rising to maximum brightness, and ‘decline in detail.
Using measurements from ASAS-SN, TESS, Swift and other observatories, including NASA’s NuSTAR and ESA’s XMM-Newton observatories, the researchers came up with three possible explanations. for repeating the flames.
One scenario involved interactions between the discs of two ultra-thin black holes at the center of ESO 253-G003.
Recent measurements show that the galaxy actually hosts two such objects, but they do not move close enough to account for the frequency of the flames.
“There is evidence of a second supermassive black hole in that galaxy,” said co-author Dr. Chris Kochanek, an astronomer at Ohio State University.
“The star that hosts this object is something of a ‘shipwreck’ made up of two galaxies that are currently coming together as one.”
The second scenario that the experts considered was a star passing a tilted orbit through a black hole disk. In that case, they would expect flames to see an irregular shape when the star hits the disc twice, on either side of the black hole. But the flames from this galaxy have the same shape.
The third scenario, and the one the team most likely thinks of, is a part-time riot incident.
In this case, one of the galaxy’s massive black holes, one with about 78 million times the mass of the sun’s orbit, disturbs part of an orbiting giant.
The orbit of the star is not round, and every time it gets closer to the black hole, it goes out, peeling off beauty but without completely breaking it apart.
Each event removes a volume of gas equal to about three times the mass of Jupiter.
“We don’t know how long the flames will last,” said the authors.
“The star can never lose a mass, and although we can estimate how much it is losing in each orbit, they do not know how big it was before the orbit began. ”
_____
Anna V. Payne et al. 2020. ASASSN-14ko is a Periodic Nuclear Transient in ESO 253-G003. ApJ, in print; arXiv: 2009.03321