**Executive Summary**
On May 6, 2026, the Ministry of Science & Technology reported that an international team of astrophysicists has uncovered how plasma composition and "kink instability" determine the appearance of extragalactic jets from supermassive black holes. The research, published in *The Astrophysical Journal*, utilizes advanced 3D simulations to explain the structural differences between FR I and FR II jet classifications. These findings provide a new framework for understanding the evolution and matter content of relativistic jets.
**Key Points / Main Content**
**Jet Classifications and Historical Context**
* **FR I Jets:** Categorized as "core-brightened," these jets are brightest near the core and fade into diffuse structures as they move outward.
* **FR II Jets:** Categorized as "edge-brightened," these stay tightly focused over long distances until they create "hot spots" upon hitting surrounding gas.
* **The Debate:** Since 1974, scientists have debated whether these differences stem from the black hole itself, the surrounding environment, or intrinsic properties like speed and magnetic strength.
**Research Methodology**
* **Simulations:** Researchers performed large 3D magnetohydrodynamic (MHD) simulations at kiloparsec scales.
* **Technical Tools:** The team used a numerical simulation code developed by the Numerical and Theoretical Astrophysics Group at ARIES, which incorporates a relativistic equation of state to handle wide temperature ranges.
**Scientific Findings**
* **Kink Instability:** This phenomenon causes "wiggles" or small bends in the jet; if the wiggle grows faster than the jet flows forward, the beam disrupts into a diffuse FR I-like cloud.
* **Plasma Composition:** Jets composed of "Leptonic/Mixed plasma" (rich in positrons) are hotter and more prone to expanding, slowing down, and twisting due to kink instability.
* **Evolutionary Nature:** Jets composed of electrons and protons (Hadronic plasma) are more likely to transition between morphologies, suggesting that observed jet types may be snapshots of a long, evolving cosmic process.
**Impact Analysis**
**Astrophysicists and Astronomers**
**Impact**
The research provides a solution to a decades-old mystery regarding why extragalactic jets appear differently in radio images. It clarifies how matter content (plasma composition) affects the physical shape and fate of these jets.
**Action Required**
Researchers should reference the findings in *The Astrophysical Journal* (DOI: 10.3847/1538-4357/ae38e2) to update observational models and theories regarding jet evolution.
**Research Institutions (ARIES, Nicolaus Copernicus Astronomical Center, etc.)**
**Impact**
The study validates the effectiveness of the specialized 3D MHD simulation codes and the relativistic equation of state developed by these institutions.
**Action Required**
These institutions may continue to refine these numerical codes to investigate other regions of extragalactic environments and jet temperatures.
Key Entities Referenced
Aryabhatta Research Institute of Observational Sciences (ARIES): The lead research institution that developed the 3D magnetohydrodynamic simulation code to investigate the behavior of extragalactic jets.
Ministry of Science & Technology: The Indian government ministry responsible for the oversight of the research and the official announcement of the findings.
Fanaroff & Riley classification: The scientific framework used to classify extragalactic radio jets into two categories (FR I and FR II), which the research aims to explain.
The Astrophysical Journal: The peer-reviewed scientific publication where the research findings on jet plasma composition and kink instability were documented.
Ministry of Science & Technology
SCIENTISTS INVESTIGATE SPECTACULARLY
DIFFERENT APPEARANCES OF
EXTRAGALACTIC JETS FROM ENVIRONMENTS
AROUND BLACK HOLES
Posted On: 06 MAY 2026 4:53PM by PIB Delhi
A team of international astrophysicists have uncovered new insights into the mystery behind the
differences in the appearances of extragalactic jets emerging from the environments of supermassive
blackholes. They showed that the plasma composition can affect the appearances of these jets. This may
help to unravel the mystery of matter content of relativistic jets.
At the centers of many distant galaxies reside supermassive black holes with masses millions to billions of
times that of our Sun. These black holes don’t just eat everything, but can also act like powerful engines,
launching narrow beams of plasma and energy known as “jets” that shoot into space at nearly the speed of
light. These extragalactic jets can travel for thousands of light-years and emit radiation ranging from low-
energy radio waves to high-energy gamma rays.
For a long time, astronomers have been wondering about a noticeable difference in radio images of
extragalactic jets, first identified by Fanaroff & Riley in 1974. They broadly classified radio jets into two
main categories: FR I & FR II. The FR I jets are "core-brightened," meaning they are brightest near the
core and gradually fade into diffuse structures as they move outward. The FR II jets, on the other hand, are
"edge-brightened," meaning they are fainter near the core but stay tightly focused over long distances until
they hit the surrounding gas, creating giant "hot spots" at their tips.
Scientists have for long continued to debate whether this difference is due to the black hole itself, the
environment around it, or the intrinsic properties of the jet, such as its speed, temperature, and magnetic
strength, etc.
A new research published in The Astrophysical Journal by Mr. Priyesh Kumar Tripathi, Dr. Indranil
Chattopadhyay, and Mr. Sanjit Debnath from Aryabhatta Research Institute of Observational Sciences
(ARIES), Dr. Raj Kishore Joshi from the Nicolaus Copernicus Astronomical Center, Poland, Dr. Ritaban
Chatterjee from Presidency University, Kolkata, and Dr. M. Saleem Khan from MJPRU Barelly, used
advanced computer simulations to reveal that the secret to these differences may be due to the jet’s
composition and the environment it travels through. The research team performed large 3D
magnetohydrodynamic (MHD) simulations of these jets at kiloparsec scales using a numerical simulation
code developed by the Numerical and Theoretical Astrophysics Group at ARIES. Notably, this code
incorporates a relativistic equation of state, which can accurately handle a very large range of temperatures
encountered at different regions of the jet.
The team discovered that a phenomenon called the "kink instability" is a major player in shaping these
powerful, narrow jets, causing wiggles (small bend). In space, if this wiggle grows faster than the jet can
flow forward, the jet beam disrupts, spreading its energy into a faint, diffuse cloud - the classic look of an
FR I jet. Astrophysical jets aren’t made of ordinary matter. Instead, they are composed of plasma, a soupof charged particles including electrons, positrons (the antimatter twin of electrons), and sometimes
heavier particles like protons. One of the study's most significant findings is that the composition of jet
plasma can determine its fate.
Jets can be made of mostly electrons and protons (Hadronic plasma), a mixture that includes positrons (the
antimatter twin of the electron-- Leptonic/Mixed plasma).
Fig: 3D Volume rendering of the jet tracer for electron-proton and mixed plasma jet
The simulations showed that jets rich in positrons (lepton-rich) are relatively hotter, causing them to
expand and slow down. They often can’t stay straight and get twisted by the kink instability. As a result,
they form a diffuse, FR I–like structure, where the jet gradually fades instead of ending in a bright hotspot.
In contrast, jets composed primarily of electrons and protons were more likely to transition between
morphologies, thereby changing their identity. This suggests that what we see through our telescopes
might just be a snapshot of a long, evolving cosmic process.
Publication: https://doi.org/10.3847/1538-4357/ae38e2
******
NKR/FT/NM
(Release ID: 2258408) Visitor Counter : 206
Read this release in: Urdu , ही