What is Cygnus X-1?

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What is Cygnus X-1? Blog Image

Overview:

Astro Sat, India’s first, dedicated multi-wavelength astronomy mission, accomplished the difficult task of measuring the X-ray polarisation of the Cygnus X-1 black hole system

About Cygnus X-1:

  • It was discovered over four decades ago.
  • It is one of the first confirmed black hole systems in our galaxy.
  • The black hole in Cygnus X-1 is 20 times heavier than the Sun, and has a companion - a heavy supergiant star (40 times more massive than the Sun) in a binary system.
  • It is located at a distance that is about 400 times more than the distance between Earth and Sun.
  • Due to the gravitational pull of the black hole, material from the supergiant falls and spirals in towards the black hole.
  • This process leads to the formation of a thin accretion disk which is responsible for soft X-rays.

Significance of X-ray Polarisation

  • Normal X-ray measurements only reveal the energy or intensity of the radiations.
  • Polarisation characteristics of X-rays, which tells about the orientation of the oscillating electric field, holds clues on the geometry and other properties of the black hole.
  • This measurement of high polarization in this source in the 100-380 keV implies that radiation emitted from the source at energies above 100 keV, is likely to have originated at the black hole jet
  • Polarization is one of the properties that a photon carries from the celestial objects in the sky. 

Q1: What are X-rays?

X-rays are a form of electromagnetic radiation, similar to visible light. Unlike light, however, x-rays have higher energy and can pass through most objects, including the body. Medical x-rays are used to generate images of tissues and structures inside the body.