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The period of 33 milliseconds and location of the Crab Nebula pulsar NP 0532 was discovered by Richard V. E. Lovelace and collaborators on 10 November 1968, at the Arecibo Radio Observatory. [ 18 ] [ 19 ] The discovery of the pulsar with such a short period proved that pulsars are rotating neutron stars (not pulsating white dwarfs, as many ...
The Crab Nebula (catalogue designations M1, NGC 1952, Taurus A) is a supernova remnant and pulsar wind nebula in the constellation of Taurus. The common name comes from a drawing that somewhat resembled a crab with arms produced by William Parsons, 3rd Earl of Rosse , in 1842 or 1843 using a 36-inch (91 cm) telescope . [ 6 ]
The Crab pulsar 33-millisecond pulse period was too short to be consistent with other proposed models for pulsar emission. Moreover, the Crab pulsar is so named because it is located at the center of the Crab Nebula, consistent with the 1933 prediction of Baade and Zwicky. [23]
It spins at a rate of 30 times per second, spewing energy beams and taking on a decidedly pulsating appearance.
Pulsed emission gamma-ray radiation from the Crab has recently been observed up to ≥25 GeV, [21] probably due to synchrotron emission by electrons trapped in the strong magnetic field around the pulsar. Polarization in the Crab nebula [22] at energies from 0.1 to 1.0 MeV, illustrates this typical property of synchrotron radiation.
Pulsar wind nebulae evolve through various phases. [2] [5] New pulsar wind nebulae appear soon after a pulsar's creation, and typically sit inside a supernova remnant, for example the Crab Nebula, [6] or the nebula within the large Vela Supernova Remnant. [7]
The Crab Nebula, and the Crab Pulsar within it, is an intense space X-ray source. It is used as a standard candle in the calibration procedure of X-ray instruments in space. However, because of the Crab Nebula's variable intensity at different X-ray energies, conversion of the Crab to another units depends on the X-ray energy range of interest.
In astronomy, a period-luminosity relation is a relationship linking the luminosity of pulsating variable stars with their pulsation period. The best-known relation is the direct proportionality law holding for Classical Cepheid variables , sometimes called the Leavitt Law .