AstroSat
Context:
AstroSat, India’s premier multi-wavelength space-based observatory, has recently identified a millisecond burst emanating from a novel neutron star with an exceptionally high magnetic field, known as a magnetar. This discovery holds the potential to deepen our comprehension of these celestial bodies and the extreme astrophysical conditions they embody.
Relevance:
GS-03 (Science and Technology)
Highlights:
- AstroSat, designed for multi-wavelength astronomical observations, captured intense sub-second X-ray bursts originating from a distinctive neutron star with an ultra-high magnetic field, identified as a magnetar.
- This finding promises valuable insights into the intricate astrophysical environments characterizing magnetars.
Magnetars:
- Magnetars are young and highly magnetized neutron stars that display a wide array of X-ray activity including short bursts, large outbursts, giant flares, and quasi-periodic oscillations, often coupled with interesting timing behavior including enhanced spin-down, glitches, and antiglitches.
- Magnetars, a subclass of neutron stars, exhibit magnetic fields significantly surpassing those found on Earth.
- To illustrate, the magnetic field of a magnetar exceeds one quadrillion times the strength of Earth’s magnetic field.
- The emission of high-energy electromagnetic radiation from magnetars is attributed to the decay of their magnetic fields.
- These celestial objects showcase notable temporal variations, including slow rotation, rapid spin-down, and brief yet luminous bursts lasting from milliseconds to months.
- An illustrative example is SGR J1830-0645, pinpointed by NASA’s Swift spacecraft in October 2020.
Research Details:
- A collaborative effort between researchers from the Raman Research Institute and Delhi University delved into the characteristics of the magnetar SGR J1830-0645 using AstroSat’s instruments—the Large Area X-Ray Proportional Counter (LAXPC) and Soft X-Ray telescope (SXT).
- The study uncovered 67 concise sub-second X-ray bursts, averaging a duration of 33 milliseconds. The most luminous burst observed endured for approximately 90 milliseconds.
- The study concluded that SGR J1830–0645 represents a distinctive magnetar, featuring an emission line in its spectra.
- The pulsed component of the overall X-ray emission exhibited notable fluctuations across different energy levels. This research contributes valuable data to our evolving understanding of magnetars and their dynamic behavior.
