Detection of Atomic Hydrogen in Distant Galaxies Using GMRT
1. What is the Giant Metrewave Radio Telescope (GMRT)?
The GMRT, located in Pune, India, is a low-frequency radio telescope designed to investigate a wide range of astrophysical phenomena. It extends from local solar systems to the edge of the observable universe.
2. What was the recent discovery made by GMRT?
GMRT detected a radio signal from atomic hydrogen in a galaxy at a redshift of z=1.29, which corresponds to when the universe was approximately 4.9 billion years old. This is the largest astronomical distance over which such a signal has been detected using the 21 cm emission line.
3. Why is atomic hydrogen important in astronomy?
Atomic hydrogen is crucial as it is the primary fuel for star formation in galaxies. It forms when hot ionized gas cools and condenses in the galactic medium, eventually leading to star formation.
4. What does the 21 cm wavelength indicate in astronomy?
The 21 cm line is the radio wavelength emitted by neutral atomic hydrogen. This line is used as a direct tracer of the atomic gas content in both nearby and distant galaxies, providing crucial data on their composition and evolution.
5. What does the term 'redshift' imply in this context?
Redshift is a measure of how much the wavelength of the light (or radio signal in this case) has been stretched due to the expansion of the universe. A higher redshift indicates that the object is farther away and that the signal comes from a more distant past.
6. What are the implications of this discovery?
The detection of atomic hydrogen in a distant galaxy using GMRT highlights the capability of current low-frequency radio telescopes to explore and understand the cosmic evolution of neutral gas across different cosmological periods. This opens new avenues for future research with existing and upcoming radio telescopes.
7. What challenges are associated with detecting 21 cm emissions from distant galaxies?
Detecting 21 cm emissions from distant galaxies is challenging due to the feeble nature of the signal and the limited sensitivity of current telescopes. This makes it nearly impossible to detect such emissions without advanced technology and significant observational time.
8. What does the detection at a redshift of z=1.29 signify about the universe's age?
The signal detected at redshift z=1.29 was emitted when the universe was only about 4.9 billion years old, providing a look-back time of approximately 8.8 billion years. This offers valuable insights into the conditions and processes occurring in the early universe.
These FAQs provide a foundational understanding of the significant discovery made by the GMRT and its implications for astronomy and our comprehension of the universe's evolutionary history.
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