Key facts
- Supermassive black hole jets can both suppress star formation by heating or disrupting gas and trigger star formation by energizing gas‑rich regions.
- The circumgalactic medium (CGM) extends roughly 10‑20 times the size of the visible galaxy and serves as a baryon reservoir that supplies gas for star formation.
- Researchers looked for H‑α emission (ionized hydrogen) as a tracer of jet impact on the CGM gas.
- When the signal was averaged over all directions around galaxies the H‑α emission was weak, but along the jet axes it became strong—about 100 times brighter than the normal halo.
Universe Today reported on Oct. 7, 2026 that a team led by Sanchayeeta Borthakur of Arizona State University and Namrata Roy of the Raman Research Institute published findings in The Astrophysical Journal Letters showing that supermassive black hole jets can both suppress star formation by heating or disrupting gas and trigger star formation by energizing gas‑rich regions.
Universe Today noted on Oct. 7, 2026 that the circumgalactic medium extends roughly 10‑20 times the size of the visible galaxy and serves as a baryon reservoir that supplies gas for star formation. Universe Today added on Oct. 7, 2026 that the influence of the jets can extend hundreds of thousands of light‑years into the galaxy’s outer halo.
ScienceDaily wrote on Oct. 11, 2026 that the study combined optical spectra from the Dark Energy Spectroscopic Instrument (DESI) survey with radio jet measurements from the LOFAR Two‑meter Sky Survey (LoTSS).
These results show that black‑hole jets can both heat and stir the circumgalactic medium, suppressing inflow of star‑forming gas, while also compressing and energizing gas‑rich clouds along their path, thereby triggering new star formation. Because the CGM extends ten to twenty times the visible galaxy and the jet influence reaches hundreds of thousands of light‑years, this feedback can regulate the baryon cycle across large galactic halos.
Eurasia Review reported on Sep. 26, 2026 that researchers looked for H‑α emission, a line from ionized hydrogen, to trace where jet energy interacts with the circumgalactic medium gas. Universe Today stated on Oct. 7, 2026 that when researchers averaged the H‑α signal over all directions around galaxies, the emission was weak, but along the jet axes it became strong—about 100 times brighter than the normal halo.
ScienceDaily noted on Oct. 11, 2026 that the strongest H‑α emission appears in two locations: near where the jet first meets the circumgalactic medium and at the outer edge of the circumgalactic medium where the jet deposits most of its energy. Note reported on Oct. 4, 2026 that jets heat, stir, and ionize gas along their path, preventing the gas from cooling and flowing inward, thereby acting as a brake on star formation.
Understanding how jets toggle between quenching and igniting star formation raises key questions about the life cycles of galaxies and the mechanisms that sustain them over cosmic time.
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