- A global team led by scientists of the Inter University Centre for Astronomy and Astrophysics (IUCAA) has discovered one of the earliest galaxies in extreme ultraviolet light.
- The team comprises scientists from India, Switzerland, France, USA, Japan and Netherlands.
- The study was and was published on August 24 in Nature Astronomy.
About: AstroSat Mission
- AstroSat is the first dedicated Indian astronomy mission aimed at studying celestial sources in X-ray, optical and UV spectral bands simultaneously.
- It was launched in 2015 into a 650 km orbit.
- AstroSat is also India’s first multi-wavelength satellite which has five unique X-ray and ultraviolet telescopes working in tandem.
Features of AstroSat:
- AstroSat has a lift-off mass of 1515 kg.
- The minimum useful life of the AstroSat mission is expected to be 5 years.
- One of the unique features of AstroSat mission is that it enables the simultaneous multi-wavelength observations of various astronomical objects with a single satellite.
- The payloads of AstroSat cover the energy bands of-
- Ultraviolet (Near and Far)
- Limited optical
- X-ray regime (0.3 keV to 100keV)
Management of AstroSat
- The spacecraft control centre at Mission Operations Complex (MOX) of ISRO Telemetry, Tracking and Command Network (ISTRAC), Bengaluru manages the satellite during its entire mission life.
- The science data gathered by five payloads of AstroSat are telemetered to the ground station at MOX.
- The data is then processed, archived and distributed by Indian Space Science Data Centre (ISSDC) located at Bylalu, near Bengaluru.
- The scientific objectives of AstroSat mission are-
- To understand high energy processes in binary star systems containing neutron stars and black holes;
- Estimate magnetic fields of neutron stars;
- Study star birth regions and high energy processes in star systems lying beyond our galaxy;
- Detect new briefly bright X-ray sources in the sky;
- Perform a limited deep field survey of the Universe in the Ultraviolet region.
Payloads of AstroSat
- Ultra Violet Imaging Telescope (UVIT)
- Its purpose is to image the sky simultaneously in three wavelengths, one covering the far UV band (130 – 180 nm) and the second sensitive in near UV (200 – 300nm) and Visible (320 – 550 nm) bands.
- The detector in each channel is a photon counting device.
- Soft X-ray Telescope (SXT)
- It is a focusing X-ray telescope with an X-ray CCD imaging camera.
- This will work primarily in photon counting mode, recording the position, time and energy of every detected photon in the energy range 0.3-8 keV.
- Large Area X-ray Proportional Counters (LAXPC)
- Its main purpose is to record variation of total intensity of sources within its 1-degree field of view, with high time resolution and moderate spectral resolution over a large spectral band from 3 to 80 keV.
- This payload is non-imaging.
- Cadmium-Zinc-Telluride Imager (CZTI)
- It is a hard X-ray coded mask camera working in the band 10-100 keV.
- It has better spectral resolution than the LAXPC and a coarse imaging capability by the coded mask.
- Scanning Sky Monitor (SSM):
- It is for detection of new X-ray transients and monitoring of known X-ray sources in 2.5 – 10 keV region.
- AstroSat has detected extreme UV light from a galaxy called AUDFs01 which is 9.3 billion light-years away from Earth.
- The galaxy is located in the Extreme Deep field.
- Deep Field is the deepest view of the universe revealed with deep space imaging of NASA’s Hubble telescope.
How AstroSat was able to detect UV Radiation from distant galaxy?
- Since UV radiation is absorbed by Earth’s atmosphere, it has to be observed from space.
- Earlier, NASA’s Hubble Space Telescope (HST) did not detect any UV emission (with energy greater than 13.6 eV) from this galaxy because it is too faint.
- NASA’s Hubble Space Telescope (HST) is significantly larger than the Ultra Violet Imaging Telescope (UVIT) on Astrosat.
- AstroSat/UVIT was able to achieve this unique feat because the background noise in the UVIT detector is much less than the ones on HST.