'Bullet Galaxy': Indian astronomers discover explosive world where stars are born using NASA's Telescope

Produced by: Tarun Mishra

Gamma-Ray Emitting Galaxy

[{"selector":"#anim-d944812b-3d67-41ba-ba6e-780b4fc239a8 [data-leaf-element=\"true\"]","keyframes":{"transform":["translate(-2.7718626390600853%, 0%) scale(1.5)","translate(0%, 0%) scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] Indian astronomers have identified a gamma-ray emitting collisional ring galaxy in the universe, named "Kathryn's Wheel," located just 30 million light-years away from the Milky Way. Credit: Gamma-ray burst illustration (Wikimedia Commons)

Formation Mechanism

[{"selector":"#anim-e6502f9f-ea32-4d2e-92f9-986a073a6347 [data-leaf-element=\"true\"]","keyframes":{"transform":["translate3d(32.52087626389477%, 0, 0)","translate3d(0%, 0, 0)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] Kathryn's Wheel forms when a smaller "bullet" galaxy penetrates a larger galaxy near its centre, generating a shockwave that collects interstellar gas, leaving behind a ring of star-forming regions and a gas-poor galaxy.

Research Findings

[{"selector":"#anim-10c2bce7-303a-47b4-a5da-f25bf3f226fd [data-leaf-element=\"true\"]","keyframes":{"transform":["translate(-1.1924679934334819%, 0%) scale(1.5)","translate(0%, 0%) scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] Published in the Astrophysical Journal Letters, the study by Prof. Vaidehi S. Paliya and Prof. Dhruba J. Saikia from IUCAA reveals intense star-forming activities in the vicinity of the central spiral galaxy, likely triggered by the collision.

Star Formation

[{"selector":"#anim-5278db55-ff30-45af-b043-5d79a167ad8c [data-leaf-element=\"true\"]","keyframes":{"transform":["translate3d(26.984141842879637%, 0, 0)","translate3d(0%, 0, 0)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] The "bullet" galaxy itself exhibits rapid star formation, with observations across radio, optical, and ultraviolet spectra revealing intense star-forming regions.

Gamma-Ray Detection

NASA's Fermi Gamma-ray Space Telescope confirmed the detection of gamma rays from Kathryn's Wheel, marking the first identification of a collisional ring galaxy system in the gamma-ray band. Credit: NASA

Significance

[{"selector":"#anim-5a2e71c6-fac7-4b25-9b14-065217dc1aae [data-leaf-element=\"true\"]","keyframes":{"transform":["translate(0%, 0%) scale(1.5)","translate(0%, 0%) scale(1)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"forwards"}] Prof. Saikia emphasizes the importance of high-resolution, multiwavelength observations in uncovering astrophysical phenomena like Kathryn's Wheel hidden within the cosmos .

Challenges

[{"selector":"#anim-e49fa553-6d02-4904-a6ea-49674927334e [data-leaf-element=\"true\"]","keyframes":{"transform":["translate3d(35.15624991466931%, 0, 0)","translate3d(0%, 0, 0)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] Despite its proximity to the Milky Way, Kathryn's Wheel has been under-studied due to nearby bright stars and its location in a crowded, low-latitude area near the Galactic plane, posing challenges for identifying astrophysical sources.

Testbed for Exploration

[{"selector":"#anim-6149006e-03ed-4b1d-a22d-6119c313a085 [data-leaf-element=\"true\"]","keyframes":{"transform":["translate3d(21.686195767977047%, 0, 0)","translate3d(0%, 0, 0)"]},"delay":0,"duration":2000,"easing":"cubic-bezier(.3,0,.55,1)","fill":"both"}] Prof. Paliya views Kathryn's Wheel as a testbed for exploring the origin and transport of cosmic rays and their connection with star-forming activities, given its proximity to the Milky Way.

Scientific Exploration

The discovery of Kathryn's Wheel offers valuable insights into the mechanisms driving star formation and cosmic ray production, highlighting the collaborative efforts of Indian astronomers in unravelling the mysteries of the universe. Credit: webbtelescope.org

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