Astronomers have made a groundbreaking discovery by directly detecting how turbulent clouds of ionized gas between stars bend and distort radio signals from distant quasars for the first time.
The radio signal from quasar TXS 2005+403 travels approximately 10 billion light-years to Earth, passing through the Cygnus region, one of the Milky Way’s most tumultuous environments. The left image depicts a quasar with a vibrant accretion disk and jets emanating into space, resembling lighthouses in the dark. The right image illustrates how turbulent gas distorts our view of the quasars, similar to how fire haze obscures objects behind it. Image credit: Melissa Weiss / CfA.
The interstellar medium, the space between stars in our Milky Way, is filled with clouds of ionized gas and electrons, creating a turbulent environment.
As radio light waves from distant quasars navigate this chaotic material, they become bent and distorted, akin to how haze from a fire blurs our vision of objects behind it.
While this distortion has allowed astronomers to infer turbulence’s presence over the years, fully understanding its intricate structure has proven challenging—until now.
Astronomer Alexander Pravin from Harvard University, alongside colleagues from the Smithsonian Center for Astrophysics, focused on the quasar TXS 2005+403 for this groundbreaking study.
This bright radio source, driven by a supermassive black hole, lies approximately 10 billion light-years away in the constellation Cygnus.
As its radio light travels toward Earth, it is refracted and altered while traversing the Cygnus region, recognized as one of the Milky Way’s most turbulent and scattering settings.
“Most of the information we gather from the radio data does not originate from the quasars themselves but rather from the scattering effects caused by turbulence in this region of the Milky Way,” stated Dr. Pravin.
“This scattering, along with the resultant distortions, enables us to investigate turbulence and improve our understanding of its structure.”
To delve deeper into the influence of turbulence on the light from TXS 2005+403, researchers analyzed nearly a decade’s worth of archival data from NSF’s Very Long Baseline Array (VLBA).
Initially, they anticipated that as the radio light passed through the Milky Way, it would gradually blur and fade.
Contrary to their expectations, they discovered distinct, consistent patterns that created structured, mottled distortions in the light—evidence of turbulence’s influence.
“The farthest pair of telescopes would typically be unable to observe the quasar image, but surprisingly, they clearly detected its faint glow,” noted Dr. Pravin.
“This phenomenon cannot be explained by simple blurring or characteristics of the quasars themselves; the effects of interstellar turbulence are evident as it behaves as theorized.”
“The scattering properties along this line of sight through the galaxy have shown persistence over time.”
For more details regarding the survey findings, check out this paper published in the Astrophysical Journal Letter.
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AV Pravin et al. 2026. Direct detection of interstellar turbulence signatures on quasars by very long baseline interferometry: TXS 2005+403. APJL 1003, L4; doi: 10.3847/2041-8213/ae60f4
Source: www.sci.news
