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Astrosat and jellyfish galaxies

Date: 04 November 2019 Tags: IT, Mobile & Computers

Issue

Observations of a jelly fish galaxy, JW100, by Astrosat using its Ultraviolet Imaging Telescope (UVIT) have shown up star formation in hostile environments containing X-ray-emitting hot plasma.

 

Background

JW100 is located far away in the galaxy cluster Abell 2626. The measurements made by the UVIT have been crucial for this work.

 

Details

  • Astrosat joins this effort by contributing data from its Ultraviolet Imaging Telescope (UVIT) instrument.

  • The jellyfish galaxies are being observed by various telescopes each sensitive to different parts of the electromagnetic spectrum.

  • The jellyfish galaxies’ tentacles contain a very hostile environment as they interact with the galaxy clusters that are rich in X-ray emitting hot plasma. What triggers star formation in these environments is a puzzle.

  • Jellyfish galaxies experience several mechanisms at the same time. Many of these happen over various timescales. The paper attempts to throw light on some of these mechanisms in JW100, using data which trace various components.

 

Jellyfish galaxy

  • Jellyfish galaxies are called so because they are shaped like discs that have many tentacle-like arms streaming away from the disc.

  • They are formed when a disc-shaped galaxy rams into a galaxy cluster, which is a dense region containing many hundreds or thousands of galaxies packed into a small region.

  • This can happen when the galaxy is attracted by the gravitational attraction of the cluster. As the individual galaxy rams into the galaxy cluster, the cold gas in its disc interacts with the hot plasma in the cluster.

  • Acting like a strong wind, the plasma in the cluster strips away the cold molecular gas of the disc, causing it to stream behind like tentacles.

  • Unlike usual galaxies that have stars forming in the disc, the jellyfish galaxies have star formation in the tentacles also.

jellyfish galaxy.jpg