Astronomers observe star formation in dwarf galaxies using Indian telescope
Have you ever wondered how stars are formed in distant dwarf galaxies? If you have, a group of astronomers from India, France, and the US led by Pune's Inter-University Centre for Astronomy and Astrophysics (IUCAA) have something for you. Using AstroSat, India's first dedicated multi-wavelength space telescope, the scientists observed new stars migrating toward the center of dwarf galaxies.
- Dwarf galaxies are thought to be important in our understanding of the evolution of galaxies. This is mainly because of their similarity to early galaxies in the universe.
- The new findings about how a dwarf galaxy takes birth will widen our knowledge about the evolution of the universe.
- If we can establish a common pattern, AstroSat's findings will be forever hailed as monumental.
The team of astronomers observed the formation of new stars in the outer regions of 11 Blue Compact Disk (BCD) galaxies or dwarf galaxies, and how they are migrating toward the center to form a dwarf galaxy. AstroSat was able to observe the galaxies in visible and ultraviolet (UV) light, marking the first time far-ultraviolet (FUV) disks have been observed in distant dwarf galaxies.
The findings of the IUCAA team are crucial as it provides scientists with information about how dwarf galaxies in the early universe acquire their stellar content. As observed by AstroSat, there was extended star formation in the outer region of these galaxies. The researchers also observed FUV disks accreting natural hydrogen gas from the surrounding intergalactic medium extending from the center of the galaxies.
Stars are formed in the low-density regions around FUV disks. The absence of these low-density gas reservoirs around present-day dwarf galaxies is either due to their evolved state or due to destruction caused by interaction with nearby galaxies. These gravitationally unstable regions get sucked toward the center due to the rotating galaxy's force and then form the galaxy.
Dwarf galaxies are little cousins of normal galaxies like the Milky Way or Andromeda. They are composed of a few billion stars and are found orbiting around larger galaxies. Milky Way has at least 14 satellite dwarf galaxies orbiting around it.
BCDs or Blue Compact Dwarfs got their name from the large number of young, hot, and massive stars they contain. These stars emit most of their energy in the UV wavelength and appear to be blue in color. As we move from inner to outer regions, these galaxies become increasingly faint. This decreases the chances of detecting them.
Unlike the James Webb Space Telescope, AstroSat observes at the other end of the electromagnetic spectrum. It can observe objects in UV, X-Ray, and visible light. Like James Webb, it also has the capability to look back into the past and observe light sources from millions of years ago. The telescope's 'lookback time' is 1.3 billion - 2.8 billion years.