“Looking towards the center of the Galaxy, we discovered ASKAP J173608.2-321635, called after its collaborates,” said co-author Professor Tara Murphy. “This things was unique in that it started out unnoticeable, became brilliant, faded away, and then came back.
” The strangest residential or commercial property of this new signal is that it is has a very high polarisation. This implies its light oscillates in just one instructions, however that direction rotates with time,” said lead author Wang. “The brightness of the object likewise differs significantly, by an element of 100, and the signal turns on and off apparently at random. Weve never seen anything like it.”
What is it? There are great deals of various types of variable stars and objects in the sky. They produce variable light all throughout the spectrum.
Could it be a low-mass star or a substellar object? Could it be a pulsar or a short-term magnetar? According to the authors, none of those possibilities matches the observations.
” At initially we thought it might be a pulsar– a really dense kind of spinning dead star– otherwise a type of star that emits huge solar flares. But the signals from this brand-new source do not match what we anticipate from these types of celestial objects,” Mr. Wang said. The object is highly polarized, similar to a pulsar, however the group didnt identify any pulsations in their data.
They also thought about magnetars as the source, which are neutron stars with severe electromagnetic fields. However the information didnt match with what we understand about magnetars either. “All radio magnetars show extremely high degrees of polarization, but their flat radio spectra, in contrast to what we see for ASKAP J173608.2? 321635, makes a magnetar a not likely interpretation,” they compose in their paper.
This image from the research study reveals the location of the variable radio source and other items in the galactic center. The yellow contours show the ASKAP detection, while the cyan contours reveal the MeerKAT detection. The best-fit positions from ASKAP and MeerKAT are revealed as yellow + and cyan × symbols, respectively. Red inverted Y signs reveal the sources from the VVV catalogue, a study of variables in the infrared. The red Gemini star is a widely known source found with the Gemini Observatory. Credit: Wang et al, 2021
The group detected 6 radio signals from the object over the course of 9 months. When they looked for the item in noticeable light, they didnt discover anything. So they decided to try spotting the item with another radio telescope in Australia, the Parkes Observatory. They discovered absolutely nothing.
Undeterred, the team performed follow-up observations with the MeerKAT radio telescope in South Africa, which is a lot more delicate. They kept inspecting with the MeerKAT to see if the intermittent signal would appear again. “We then tried the more delicate MeerKAT radio telescope in South Africa. Due to the fact that the signal was intermittent, we observed it for 15 minutes every few weeks, hoping that we would see it again,” said Dr. Murphy.
This picture of the main part of the Milky Way shows an area of 1000 x 500 light years and was taken with the MeerKAT telescope stationed in South Africa, a system consisting of 64 radio antennas. © SARAO
They got fortunate. The signal returned. Not in a method that they anticipated.
” Luckily, the signal returned, however we found that the habits of the source was dramatically different– the source disappeared in a single day, despite the fact that it had actually lasted for weeks in our previous ASKAP observations,” said Murphy.
The team thought it might be a type of things called a Galactic Center Radio Transient (GCRT). The new item was detected just 4 degrees from the galactic.
” The details we do have has some parallels with another emerging class of mysterious items called Galactic Centre Radio Transients, consisting of one called the cosmic burper,” said Mr. Wangs co-supervisor, Professor David Kaplan from the University of Wisconsin-Milwaukee.
” While our new things, ASKAP J173608.2-321635, does share some homes with GCRTs there are likewise differences. And we dont actually comprehend those sources, anyway, so this includes to the secret.”
This is a composite infrared picture of the Milky Ways galactic center. It reveals brand-new details in complex structures in the hot ionized gas swirling around the central 300 light-years. Credit: Hubble: NASA, ESA, and Q.D. Wang (University of Massachusetts, Amherst); Spitzer: NASA, Jet Propulsion Laboratory, and S. Stolovy (Spitzer Science Center/Caltech).
For now, the brand-new item will remain a mystery. The Australian SKA itself is simply one piece of the eventual Square Kilometer Array, a global radio interferometer that will be made up of thousands of dishes around the world.
” Within the next decade, the transcontinental Square Kilometer Array ( SKA) radio telescope will come online. It will be able to make sensitive maps of the sky every day,” Professor Murphy stated. “We anticipate the power of this telescope will help us fix mysteries such as this latest discovery, however it will also open vast new swathes of the universes to exploration in the radio spectrum.”.
Future studies will discover more information on this brand-new item and others like it. Will it turn out to be a Galactic Center Radio Transient?
” ASKAP J173608.2? 321635 is additional noteworthy for its location towards the GC, although we do not yet understand whether that is a coincidence or if that place is related to its nature: comparable questions might be raised about the GCRT sources. Future detailed searches will measure the exact variety of such sources at different places in the sky,” the authors write.
Originally published on Universe Today.
For more on this discovery:.
Reference: “Discovery of ASKAP J173608.2-321635 as a Highly-Polarized Transient Point Source with the Australian SKA Pathfinder” by Ziteng Wang, David L. Kaplan, Tara Murphy, Emil Lenc, Shi Dai, Ewan Barr, Dougal Dobie, B. M. Gaensler, George Heald, James K. Leung, Andrew OBrien, Sergio Pintaldi, Joshua Pritchard, Nanda Rea, Gregory R. Sivakoff, B. W. Stappers, Adam Stewart, E. Tremou, Yuanming Wang, Patrick A. Woudt and Andrew Zic, 12 October 2021, The Astrophysical Journal.DOI: 10.3847/ 1538-4357/ ac2360.
Artists impression of the oscillating, variable radio signal ASKAP J173608.2-321635 coming to Earth from towards the center of the Milky Way. Credit: Sebastian Zentilomo/University of Sydney
The center of the Milky Way is a mysterious place. Astronomers think theres a supermassive great void there, though it could be dark matter instead. The region is densely packed with stars, controlled by red giants. And because of all the dust between Earth and the galactic center, we cant see anything with visible light, ultraviolet light, or low-energy x-rays.
But we can discover radio waves, and there are some inexplicable ones coming from the center of the galaxy, and including to the secret.
Astronomers have actually found a short-term source of radio waves at the Milky Ways. The lead author is Ziteng Wang, a Ph.D. trainee in the School of Physics at the University of Sydney.
Astronomers have actually found a short-term source of radio waves at the Milky Ways. “All radio magnetars reveal extremely high degrees of polarization, however their flat radio spectra, in contrast to what we see for ASKAP J173608.2? The group detected 6 radio signals from the things over the course of nine months. They decided to try finding the things with another radio telescope in Australia, the Parkes Observatory. The group thought it could be a type of object called a Galactic Center Radio Transient (GCRT).