Astronomers have discovered the Milky Way’s first confirmed microblazar, identifying a stellar-mass black hole in the binary system IRAS 18293−0941 that fires a near-light-speed particle jet directly toward Earth. Found after decades of hiding behind interstellar dust, the system acts as a miniature particle accelerator.
For roughly three decades, astronomers suspected that stellar-mass microblazars should exist within our galaxy. Finding one proved difficult. The binary system known as IRAS 18293−0941 sat behind a dense wall of interstellar gas and dust, making it essentially invisible in ordinary optical images according to researcher leader Josep Martí of the University of Jaén, Spain. Although the Infrared Astronomical Satellite originally detected the object in 1983, it attracted little attention for decades.
The breakthrough began when astronomers noticed the light of the system’s star flickering. That flicker revealed an 11-day orbital period for a companion black hole, which scientists realized they were observing almost face-on.
Radio Imaging and the European VLBI Network Confirmation
Further clues emerged through radio observations, which exposed a bright central source paired with a narrow, elongated structure extending from only one side. Because black holes pull material from their surroundings to launch two opposing jets, scientists knew a second jet should exist.
To confirm that the jet genuinely belonged to the stellar binary rather than an unrelated background galaxy, an international team launched an extensive observation campaign. High-resolution radio imaging using the European VLBI Network (EVN) provided exceptionally sharp pictures of the system. Researchers then compared those radio coordinates with positional data from the European Space Agency’s Gaia spacecraft.
Benito Marcote from the Joint Institute for VLBI ERIC, JIVE, explained that the EVN position combined with the known position from Gaia verified that the jet belonged directly to the stellar system.
Particle Acceleration and Interstellar Impact
The mechanics inside IRAS 18293−0941 mirror supermassive blazars found at the centers of distant galaxies, but on a much smaller scale. This matter forms an accretion disk that propels twin jets outward.
While one jet points toward Earth at roughly 0.75 times the speed of light, the opposite jet slams into an enormous cloud of interstellar gas and dust. Astronomers detected the effects of this hidden second jet using the MeerKAT radio observatory in South Africa, uncovering a 100-light-year-wide bubble. At the edge of that bubble, a hotspot glows as the collision accelerates particles and warms dust.
Broader Implications for Galactic Physics
The discovery of a local microblazar provides scientists with an accessible laboratory to examine phenomena typically locked inside distant active galaxies. Having a close analog within the Milky Way allows researchers to study how feeding black holes pour energy into surrounding galaxies.
The findings have been accepted for publication in the journal Astronomy & Astrophysics following a coordinated, multi-waveband observational campaign.