Brian's Einstein@Home Stuff

  
     
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Green Bank telescope:

The Robert C. Byrd Green Bank Telescope (GBT) in Green Bank, West Virginia, US is the world's largest fully steerable radio telescope.

With a 100-meter-class collecting dish, GBT is one of the largest fully steerable single-dish radio telescopes in the world. Its sensitivity and wide frequency coverage make it ideal for detecting faint radio signals from pulsars and other astrophysical sources.

In Einstein@Home, the GBT provides data for pulsar searches, particularly for binary pulsars. The volunteer computers analyze GBT data to identify the characteristic periodic radio pulses of neutron stars, including those in tight orbits where the signals are Doppler-shifted by orbital motion. Alongside Arecibo and MeerKAT data, the GBT has contributed to discovering hundreds of pulsars, helping to expand our understanding of neutron star populations, millisecond pulsars, and exotic binary systems.

  • Neutron stars are the incredibly dense remnants of massive stars that exploded as supernovae. They typically have a mass about 1.4 times that of the Sun, compressed into a sphere roughly 20 kilometers (12 miles) across. This extreme density means a neutron star’s matter is packed so tightly that a sugar-cube-sized piece would weigh billions of tons on Earth. Neutron stars often have very strong magnetic fields and can spin rapidly, emitting beams of radiation from their magnetic poles — these are observed as pulsars when the beam sweeps past Earth.

  • Pulsars in Tight Orbits & Doppler Shifts; Some pulsars are in binary systems with another star, sometimes in tight orbits, meaning the two stars orbit each other very quickly. Because the pulsar is moving toward or away from Earth during its orbit, the pulses we detect are Doppler-shifted (when the pulsar moves toward us, the pulse frequency appears slightly higher, and when it moves away, the frequency appears lower.) This effect makes the timing of the pulses appear to vary slightly, which complicates the search but also provides crucial information about the pulsar’s orbital period, velocity, and companion mass. Einstein@Home’s computing power is used to analyze these shifts and identify pulsars in such dynamic binary systems.