Indian scientists find new way to measure distances in deep space, PgII

Key Highlights:

• Indian astronomers, including those from IIT-Kanpur, have discovered a new method to measure distances in the universe using pulsars.
• The technique involves studying the distortion of radio emissions from pulsars as they travel through space.
• The method combines the effects of dispersion measure (DM) and scatter broadening of pulsar signals.
• The study refines distance estimates by locating turbulent plasma between the Earth and the pulsar.
• Researchers analyzed 10 pulsars in the region of the Gum Nebula to refine their model.

Detailed Insights:

• Pulsars, rapidly spinning cores of dead stars, emit radio waves used as cosmic clocks due to their fixed spinning rate.
• Pulsar timing experiments utilize millisecond pulsars to detect astrophysical events like gravitational waves by observing differences in pulse arrival times.
• Radio waves passing through the galaxy encounter ionised gas (plasma), which contains free electrons that alter the radio signal.
• Dispersion measure (DM) estimates the number of electrons between Earth and the pulsar by measuring the delay of radio waves.
• The interstellar medium affects pulsar signals through scattering, causing scintillation and scatter broadening.
• The new method combines DM with scatter broadening to more accurately determine the location of turbulent plasma.
• The team developed a refined model of the Gum Nebula's electron distribution, showing that the Vela Pulsar lies behind the nebula's front shell.
• Unlike parallax techniques, this new method has no specific distance limitation and could potentially measure distances to objects outside the Milky Way.

Scientific/Technical Concepts Involved:

• Pulsars: Dense, rapidly spinning remnant cores of dead stars that emit beams of radio waves.
• Dispersion Measure (DM): A measure of the delay in radio waves caused by free electrons in the interstellar medium.
• Scatter Broadening: The stretching or smearing of pulsar signals due to scattering in the interstellar medium.
• Interstellar Medium: The matter and radiation that exists in the space between star systems in a galaxy.