Thanks to ever more efficient instruments, astronomers continue to make astonishing discoveries. Today, a mysterious radio signal from the center of the Milky Way. The investigation to determine its origin is open.
You will also be interested
[EN VIDÉO] The first radio signal from an exoplanet Researchers at Cornell University (United States) recorded what looks like a radio signal from an exoplanet about 50 light years from Earth, Tau Bootis Ab. The signature, they tell us, of its magnetic field. The promise of now having a new tool to study planets located outside our Solar System. @ Ryan MacDonald, Carl Sagan Institute, Cornell University
L’Australian Square Kilometer Array Pathfinder (Askap) – understand the network of radiotélescopes Australian square kilometer – is one of the most sensitive radio telescopes in the world. It has already enabled astronomers from discover galaxies or to record the famous bursts radio fast – what English speakers call Fast Radio Bursts (FRB) and which we will talk about soon on Futura, in the company of Françoise Combes, astrophysicist and CNRS 2020 gold medalist.
This time, the Askap unveils a mysterious transient signal coming from the center of the Milky Way. The Sydney University astronomers (Australia) named it ASKAP J173608.2-321635. But they still do not know what object could be at the origin. The properties of this signal indeed appear to be the strangest. And it wouldn’t be the first time that a mysterious radio source has disclosed an unusual event. As recently as last week, the example of this star which exploded while swallowing a black hole !
Astronomers report that the ASKAP J173608.2-321635 signal is highly variable. It can emit for several weeks. Then disappear. Between April 2019 and August 2020, it appeared 13 times in the Askap data. In February 2021, it was detected for the very first time by the MeerKAT radio telescope (South Africa). Ditto in April 2021 for the detection reported by theAustralian Telescope Compact Array (Atca). As if to confirm the elusiveness of the signal radio which had hitherto gone unnoticed.
Already a few tracks eliminated
All the more unnoticed, perhaps, as no signal to another wave length does not accompany it. Nothing on the side of X-rays or near infrared. Nothing in the archives of radio observations either.
Astronomers also note that ASKAP J173608.2-321635 is strongly polarized. What to suggest a diffusion and magnetization. But are these the result of dust and magnetic fields encountered by the signal in its journey to us or from the source of the signal itself? The question remains open.
However, in their quest to identify the source of this mysterious signal, astronomers are already eliminating several leads. For example, it is not a star eruptive. Because the radio signal would then be accompanied by a emission in the field of X-rays. Neither is it a question of pulsar whose periodicity would be much more regular than that observed for ASKAP J173608.2-321635.
Perhaps while ASKAP J173608.2-321635 should be classified among those that English speakers call the Galactic Center Radio Transients (GCRT) – understand, the transient signals coming from the center of the Galaxy. In the 2000s, astronomers identified three of these signals. Others are awaiting confirmation. Researchers still do not know the source. But ASKAP J173608.2-321635 shares several characteristics with GCRTs. If confirmed to be this, it could be evidence that there are similar sources that have yet to be observed. Particularly because of their inconstancy.
Interested in what you just read?
.
