Context: ISRO (India) is set to launch its first X-Ray Polarimeter Satellite. 

X-Ray Polarimeter Satellite (XPoSat): Key Highlights

• X-Ray Polarimeter Satellite (XPoSat) will be launched by the Polar Satellite Launch Vehicle (PSLV) from the Satish Dhawan Space Center in Sriharikota. 
•  Aim: It is India’s pioneering polarimetry mission aimed at studying various dynamics of astronomical sources in extreme conditions.
• It is only the world’s second polarimetry mission using X-ray after NASA’s Imaging X-ray Polarimetry Explorer (IXPE) that was launched in 2021.

About XPoSat

• XPoSat, India’s pioneering X-ray Polarimeter Satellite, marks the country’s first dedicated mission to delve into the dynamics of astronomical X-ray sources. 
• XPoSat Objective: To explore various dynamics of bright astronomical X-ray sources in extreme conditions.
• It carries two main scientific payloads in low Earth orbit:
• POLIX (Polarimeter Instrument in X-rays): 
  • Measures polarization parameters in the medium X-ray energy range (8-30 keV) from astronomical sources. 
  • Developed by Raman Research Institute (RRI) in collaboration with U R Rao Satellite Centre (URSC).
  • Functionality: Polarimeter for astronomical observations in the 8-30 keV energy band.
  • Components: Includes a collimator, scatterer, and four X-ray proportional counter detectors.
  • Objective: Intends to observe nearly 40 bright astronomical sources over XPoSat’s planned 5-year mission lifespan, providing significant polarimetry insights.
• XSPECT (X-ray Spectroscopy and Timing)
  • It provides spectroscopic information in the energy range of 0.8-15 keV for various X-ray sources, enhancing timing accuracy and resolution.
  • Features: Provides high-resolution spectroscopic information and timing capabilities in the 0.8-15 keV X-ray energy range.
  • Instrumentation: Employs Swept Charge Devices (SCDs) with superior energy resolution and passive collimators for background reduction.
  • Scope: Targets various sources, including X-ray pulsars, black hole binaries, and active galactic nuclei, enabling long-term monitoring and spectral state observations.
• Significance of XPoSat in comprehending astronomical sources
  • Diagnostic method: Utilizing polarimetry measurements serves as a crucial diagnostic method for deciphering the emission processes from diverse astronomical sources.
  • Understanding the complexity of Astronomical Emission Mechanisms:  By amalgamating polarimetric observations with spectroscopic and timing measurements, scientists envisage surpassing the constraints of the current comprehension regarding astronomical emission processes.

Source: The Hindu