Astronomers have discovered a strange new object that behaves differently from any of those observed before. It is hoped that this source will provide much-needed insight into the origin of the mysterious cosmic signals that have puzzled experts for the past few years.
A team of researchers led by astronomers from the International Center for Radio Astronomy Research (ICRAR) in Australia found the object, known as ASKAP J1832-0911, using the ASKAP radio telescope, which picked up radio wave pulses emanating from it.
This suggests that it belongs to a mysterious, recently discovered class of objects called long-period transients (LPTs), which emit radio pulses at unusually long and regular intervals – typically minutes or hours. Since LPT signals were first detected by ICRAR astronomers in 2022, only 10 such objects have been documented, the organization said in a statement.
Astronomers are still trying to figure out what exactly LPTs are and why they exhibit such strange behavior. In March, there was a new breakthrough in the case when a study linked LPT pulses to a double star system consisting of a white and a red dwarf, but J1832-0911 was particularly strange. While the ASKAP radio telescope was observing it, NASA’s Chandra X-ray Observatory happened to be looking at the same area of the sky. This revealed that the object, located in the Milky Way at a distance of about 15,000 light-years from Earth, was also emitting pulses of X-rays.
Detecting the X-rays from ASKAP J1832-0911 “was like finding a needle in a haystack,” said lead author Ziteng (Andy) Wang, an astronomer at Curtin University, part of ICRAR, in a statement. “The ASKAP radio telescope has a wide field of view of the night sky, while Chandra only observes a fraction of it. So, we were fortunate that Chandra was observing the same part of the night sky at the same time.”
This is the first time that X-ray emission has been observed with the LPT. J1832-0911 emits radio waves and X-rays simultaneously for two minutes at 44-minute intervals, exhibiting properties that are “unique among known galactic objects and require a new explanation,” the authors state in their paper published today in the journal Nature.
Uncovering the true nature of J1832-0911 will require further research, but Wang and his colleagues already have some initial ideas about what it might be.
“ASKAP [J1832-0911] could be a magnetar (a dead star core with strong magnetic fields),” he said. Simultaneous pulses of radio waves and X-rays have been observed from magnetars before.
In addition, “it could be a pair of stars in a double system where one of them is a strongly magnetized white dwarf (a low-mass star at the end of its evolution),” Wang added. In this scenario – which has also been documented before – the interaction between the rapidly rotating magnetized white dwarf and its companion causes the system to emit pulses that span the entire electromagnetic spectrum, from X-rays to radio waves.
But, according to Wang and his colleagues, none of these possibilities can fully explain what they observed with J1832-0911. Thus, this discovery may indicate that some new physics is at work, or that astronomers need to adjust existing models of stellar evolution.
The search for other such bizarre objects is ongoing. “The discovery of one such object hints at the existence of many others,” study co-author Nanda Rea, an astrophysicist at the Institute of Space Sciences (ICE-CSIC) and the Institute of Space Research of Catalonia (IEEC) in Spain, said in a statement. She said the discovery of J1832-0911’s transient X-ray emission “opens up new insights” into the mysterious nature of LPTs.
