The mysterious radio signal in the center of the Milky Way that scientists want to understand

The center of the Milky Way galaxy, imaged by the Spitzer Space Telescope’s infrared cameras .. NASA, JPL-Caltech, Susan Stolovy (SSC/Caltech) et al.

It could be a rare and mysterious class of objects known as radio transients of the galactic center.

A strange radio signal. Repetitive From where? From the center of the Milky Way, our galaxy. Apparently, according to a new article published in the Astrophysical Journal, it does not belong to anything that we know of, that is, to any type of energetic signal ever recorded. The article, which can be found on arXiv, defines the power source as extremely distinguishable, appearing brilliantly in the radio spectrum for weeks and then suddenly disappearing within a day.

It is a type of attitude that does not conform to any type of celestial body, the researchers write in the article, and therefore could represent “a new class of objects discovered through radio images.” But what kind of objects? The signal, cataloged as ASKAP J173608.2-321635, was detected by the Australian Square Kilometer Array Pathfinder radio telescope, located in the heart of Australia. In the analyzed time frame, that is, between April 2019 and August 2020, the strange signal appeared 13 times, and never lasted more than a few weeks.

There does not appear to be a clear pattern to these appearances, and it does not appear to have been detected by other radio telescopes in the past.

When the researchers tried to match the energy source with observations from other telescopes, including the Chandra X-ray Observatory and the Neil Gehrels Swift Observatory, as well as the Visible and Infrared Survey Telescope for Astronomy in Chile, the signal disappeared completely. . With no apparent emissions anywhere else on the electromagnetic spectrum, “ASKAP J173608.2-321635 is a radio phantom that seems to defy explanation,”

Low-mass stars that periodically emit a signal? Maybe, but these bodies often have X-ray homologues, in this case undetectable. In short, a stellar origin – dying stars like pulsars or magnetars – seems unlikely.

In short, a stellar origin – dying stars like pulsars or magnetars – seems unlikely. For example, pulsars can transmit radio beams of light beyond Earth and rotate with predictable periodicity, on a time scale of hours, not weeks. Magnetars, on the other hand, always include a powerful X-ray counterpart with each of their explosions. ASKAP J173608.2-321635 looks very different.

One possible candidate could be the GCRT, a mysterious class of objects known as Galactic Center Radio Transients (GCRT), a rapidly illuminated radio source that lights up and decays near the center of the Milky Way, usually over the course of some hours. So far only three are known, but, again, they all appear and disappear faster than the enigmatic ASKAP, with which they share the absence of X-ray emission and the brightness of their luminosity.