An international team of researchers has identified the most promising candidate to date for a microblazar, a rare cosmic phenomenon predicted but never before confirmed. The discovery offers astronomers a closer look at how black holes emit powerful jets of energy and could shed light on extreme astrophysical behaviors.
Blazars are among the most energetic objects in the universe. They belong to a class of quasars fueled by supermassive black holes consuming matter from their host galaxies and ejecting particles and radiation in opposing jets traveling near the speed of light. For an object to be classified as a blazar, one of these jets must be directed straight toward Earth.
While astronomers had previously discovered smaller counterparts known as microquasars, the existence of microblazars remained purely theoretical. Now, a study led by scientists from Spain, the Netherlands, and Argentina describes a specific object that fits the profile. The findings have been accepted for publication in the journal Astronomy and Astrophysics.
“It is the first time that we have a serious candidate,” said Josep Martí, an astronomer at the University of Jaén in Spain and the study’s lead author. “Because of stellar evolution, you need to catch the system at the right time. The microquasar phase of evolution is very short, and so it is difficult to find one in that phase,” he added.
The candidate, designated IRAS 18293-0941, resides approximately 12,000 light-years from Earth within our own galaxy, obscured by interstellar dust. It is part of a binary system where a black hole orbits a massive, hot star every 11 days. As matter is pulled from the star into the black hole, some of it is expelled outward in two opposing jets, with one jet flaring directly toward our planet.
Theoretical models suggest microblazars should exhibit specific traits, including intense emissions across the electromagnetic spectrum, rapid brightness fluctuations due to Doppler boosting, and a hotspot formed where the opposing jet collides with the surrounding interstellar medium.
To investigate IRAS 18293-0941, the team utilized instruments such as the Calar Alto Astronomical Observatory in Spain, the European VLBI Network, the MeerKAT radio telescope array in South Africa, and archival data from the Very Large Array in New Mexico.
The observations confirmed most expected characteristics, with the exception of rapid variability. However, Martí suggested that a dense cloud of gas surrounding the object could be smoothing out quick fluctuations in brightness, accounting for this discrepancy.
Co-author Pedro Luque-Escamilla, also from the University of Jaén, noted that researchers are currently analyzing whether the observed region behind the microblazar constitutes the predicted hotspot.
Despite the missing variability, the scientific community has responded positively to the findings. Kinwah Wu, a theoretical astrophysicist at University College London who was not involved in the research, described the claims as sensible and free of questionable assumptions. He highlighted that the source showed clear signs of interaction between jets and ambient material.
Svetlana Jorstad, a senior research scientist at Boston University, called the study “very interesting, important and comprehensive.” Meanwhile, Itumeleng Monageng of the University of Cape Town emphasized that the observations reveal a previously overlooked mechanism for generating some of the highest-energy emissions observed in the cosmos.
“Microblazars may power some of the universe’s most energetic processes,” Monageng said.
Twelve thousand light-years away yet it still powers such energetic processes. The universe never ceases to amaze.
No rapid variability though? I wonder if they missed some data points or if the gas cloud really is that dense.
Wait, so one jet points at us? That explains the intense emissions. Fascinating!
Finally, evidence for something purely theoretical! This feels like a major milestone for astrophysics.