Astronomers have detected an odd, repeating radio sign close to the middle of the Milky Way, and it is in contrast to some other vitality signature ever studied.
According to a brand new paper accepted for publication in The Astrophysical Journal and posted on the preprint server arXiv, the vitality supply is extraordinarily finicky, showing brilliant within the radio spectrum for weeks at a time after which utterly vanishing inside a day. This habits does not fairly match the profile of any recognized sort of celestial physique, the researchers wrote of their research, and thus could signify “a new class of objects being discovered through radio imaging.”
The radio supply — generally known as ASKAP J173608.2−321635 — was detected with the Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope, located within the distant Australian outback. In an ASKAP survey taken between April 2019 and August 2020, the unusual sign appeared 13 instances, by no means lasting within the sky for various weeks, the researchers wrote. This radio supply is very variable, showing and disappearing with no predictable schedule, and does not appear to seem in some other radio telescope information previous to the ASKAP survey.
When the researchers tried to match the vitality supply with observations from different telescopes — together with the Chandra X-ray Observatory and the Neil Gehrels Swift Observatory, in addition to the Visible and Infrared Survey Telescope for Astronomy in Chile, which might decide up near-infrared wavelengths — the sign disappeared completely. With no obvious emissions in some other a part of the electromagnetic spectrum, ASKAP J173608.2−321635 is a radio ghost that appears to defy clarification.
Prior surveys have detected low-mass stars that periodically flare up with radio vitality, however these flaring stars sometimes have X-ray counterparts, the researchers wrote. That makes a stellar supply unlikely right here.
Dead stars, like pulsars and magnetars (two forms of ultradense, collapsed stars), are additionally unlikely explanations, the staff wrote. While pulsars can stream brilliant beams of radio mild previous Earth, they spin with predictable periodicity, often sweeping their lights previous our telescopes on a timescale of hours, not weeks. Magnetars, in the meantime, at all times embody a robust X-ray counterpart with every of their outbursts — once more, in contrast to ASKAP J173608.2−321635’s habits.
The closest match is a mysterious class of object generally known as a galactic middle radio transient (GCRT), a quickly glowing radio supply that brightens and decays close to the Milky Way’s middle, often over the course of some hours. So far, solely three GCRTs have been confirmed, and all of them seem and disappear rather more shortly than this new ASKAP object does. However, the few recognized GCRTs do shine with an analogous brightness because the mysterious sign, and their radio flare-ups are by no means accompanied by X-rays.
If this new radio object is a GCRT, its properties push the boundaries of what astronomers thought GCRTs had been able to, the researchers concluded. Future radio surveys of the galactic middle ought to assist clear up the thriller.
Originally revealed on Live Science.