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Topic: Crab Pulsar

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	Crab Nebula - Wikipedia, the free encyclopedia
		The energy released as the pulsar slows down is enormous, and it powers the emission of the synchrotron radiation of the Crab Nebula, which has a total luminosity about 75,000 times greater than that of the Sun.
		A significant problem in studies of the Crab Nebula is that the combined mass of the nebula and the pulsar add up to considerably less than the predicted mass of the progenitor star, and the question of where the 'missing mass' is remains unresolved.
		The predominant theory to account for the missing mass of the Crab is that a substantial proportion of the mass of the progenitor was carried away before the supernova explosion in a fast stellar wind.
	en.wikipedia.org /wiki/Crab_Nebula (2378 words)

	Encyclopedia :: encyclopedia : Pulsar (Site not responding. Last check: 2007-10-29)
		Pulsars are rotating neutron stars that are observable as sources of electromagnetic radiation.
		For example, X-ray pulsars are probably old rotation-powered pulsars that have already lost most of their energy, and have only become visible again after their binary companions expanded and began transferring matter on to the neutron star.
		The first radio pulsar, CP 1919 (now known as PSR B1919+21), with a pulse period of 1.339 seconds and a pulse width of 0.04 second, was discovered in 1967 (Nature 217:709-713, 1968).
	www.hallencyclopedia.com /Pulsar (587 words)

	Crab Nebula
		At the centre of the nebula is the Crab Pulsar, a neutron star remnant of the supernova which is roughly 10 kilometers in diameter discovered in 1969.
		The Crab Pulsar rotates 33 times each second, and the beams of radiation it emits interact with the nebular gasses to produce complex patterns of wind and fluorescence.
		The Crab nebula is often used as a calibration source in X-ray astronomy.
	www.ebroadcast.com.au /lookup/encyclopedia/cr/Crab_nebula.html (322 words)

	The Sounds of Pulsars
		A pulsar is a highly magnetised neutron star, with a radius of 10-15 km, having somewhat greater mass than the Sun which has a radius of approximately 1 million km.
		This pulsar lies near the centre of the Vela supernova remnant, which is the debris of the explosion of a massive star about 10,000 years ago.
		This is the youngest known pulsar and lies at the centre of the Crab Nebula, the supernova remnant of its birth explosion, which was witnessed by Europeans and Chinese in the year 1054 A.D. as a day-time light in the sky.
	www.jb.man.ac.uk /~pulsar/Education/Sounds/sounds.html (356 words)

	Crab Pulsar - Wikipedia, the free encyclopedia
		The Crab Pulsar (PSR B0531+21) is a supernova remnant located in the Crab Nebula, discovered in 1969.
		The period of the pulsar's rotation is slowing by 38 nanoseconds per day due to the large amounts of energy being radiated.
		It is very bright in X-rays and the flux density and spectrum are known to be constant, with the exception of the pulsar itself.
	en.wikipedia.org /wiki/Crab_Pulsar (281 words)

	Pulsar Bursts Coming From Beachball-Sized Structures
		Pulsars are superdense neutron stars, the remnants of massive stars that exploded as supernovae.
		Although the mechanism that converts the plasma energy to radio waves in the Crab's "giant" pulses may be unique to the Crab pulsar, it is feasible that all radio pulsars may operate the same way.
		The Crab Nebula is a cloud of glowing debris from a star that was seen to explode on July 4, 1054.
	www.nrao.edu /pr/2003/pulsaremission (953 words)

	The Youngest Pulsar Yet (Site not responding. Last check: 2007-10-29)
		This pulsar, in the supernova remnant Kes 75, is about 300 years younger than the Crab pulsar, which used to be the youngest known.
		Yet, compared to the Crab, the Kes 75 pulsar spins ten times more slowly; it is slowing down at a rate ten times faster; and it has a magnetic field that is ten times greater - all unexpected findings that may cause scientists to rethink the birth properties and evolution of pulsars.
		The pulsar's age is 700 years, consistent with the age of the supernova remnant that houses it.
	www.firstscience.com /SITE/ARTICLES/pulsar.asp (862 words)

	Crab Nebula (M1, NGC 1952)
		In 1948, the Crab was identified as a strong source of radio waves, and catalogued as Taurus A and, later, as 3C 144.
		The Crab Nebula was discovered in 1731 by the British physician and amateur astronomer John Bevis (1695-1771) according to Charles Messier, who independently found it on Aug. 28, 1758, and first thought it was a comet, when looking for Halley’s Comet on its first predicted return.
		The pulsar associated with the Crab Nebula has a period of 33.085 milliseconds, corresponding to a spin rate of 30 revolutions per second, and is one of the few pulsars detected at optical wavelengths.
	www.daviddarling.info /encyclopedia/C/Crab.html (703 words)

	Hubble views the Crab Nebula M1 (Site not responding. Last check: 2007-10-29)
		The pulsar itself is visible as the left of the pair of stars near the center of the frame.
		The tiny pulsar and its wind are the powerhouse for the entire Crab Nebula, which is 10 light-years across -- a feat comparable to an object the size of a hydrogen atom illuminating a volume of space a kilometer across.
		As the observer pulls away from the pulsar, first the "inner knot" appears from the upper left, then followed by the "sprite", and finally, the jets which appear on opposing sides of the pulsar.
	www.seds.org /messier/more/m001_h2.html (902 words)

	NASA - Chandra X-ray Observatory Quick Facts: Crab Nebula
		The Crab Nebula is the remnant of a star that was observed to explode in 1054 A.D. It is located 6,000 light years away in the constellation of Taurus, and is a strong source of wavelengths from radio waves through gamma ray waves.
		The pulsed emission from the Crab Nebula, observed at all wavelengths from radio through gamma rays, is thought to be caused by this process.
		The Crab Nebula's bell-shaped appearance in the X-ray image is due to synchrotron radiation from a huge magnetized bubble of high-energy electrons that is several light years in diameter.
	www.nasa.gov /centers/marshall/news/background/facts/CrabNebulaFactSheet.html (566 words)

	The Crab Nebula
		The supernova which produced the Crab Nebula was observed by the Chinese in 1054 AD.
		The Crab pulsar is slowing at the rate of about 10^-8 sec per day, and the corresponding energy loss agrees well with the energy needed to keep the nebula luminous.
		Almost coincident with the observation of the supernova, a burst of neutrinos were observed on the Earth, providing further information for modeling supernovae and providing another test for the mass of the neutrino.
	hyperphysics.phy-astr.gsu.edu /hbase/astro/crab.html (441 words)

	Pulsars
		The Crab Nebula (adjacent image) is a strong source of electromagnetic radiation across the spectrum, and most of the power for this emission is being derived from the spinning neutron star and its strong fields lying at the center of the nebula.
		Although the Crab Pulsar emits visible light (and X-rays and gamma-rays), most pulsars are detectable only by their RF radiation.
		The movie imagines that you are close to the Crab Pulsar and slowly pull away, allowing you to see more and more of what is going on to power the inner part of the nebula and to account for the detailed activity seen in the preceding animation (more info).
	csep10.phys.utk.edu /astr162/lect/pulsars/pulsars.html (1153 words)

	Crab Nebula and Pulsar
		About 10 light-years (ly) across, the Crab Nebula (M1 or NGC 1952) is the remnant of a supernova explosion that was seen on Earth beginning on July 4th, 1054 CE.
		The progenitor star of the Crab Nebula was once a main sequence dwarf of spectral type O or B (Mdzinarishvili and Dzigvashvili, 2001).
		The Crab Nebula emits radiation from the motion of high-speed electrons being accelerated or decelerated in its magnetic field by its the pulsar.
	www.solstation.com /x-objects/crab-neb.htm (1322 words)

	The Pulsar Sky Above 10 GeV
		The cross denotes the position of the Crab pulsar and the solid circle the 95% acceptance area for photons above 10 GeV relative to the Crab.
		Thus, Crab and PSR B1951+32 may have a similar pulsed brightness above 10 GeV, whereas PSR B1951+32 is much weaker compared to the Crab near 100 MeV, which is a result of the harder spectrum of PSR B1951+32.
		Crab and PSR B1951+32 will be prime candidates for MAGIC (pulsar mode) given their optimal declinations relative to the latitude of La Palma.
	www.gae.ucm.es /~marcos/tesina/html/node67.html (860 words)

	Pulsar Tutorial
		The Crab Nebula (at right), is the remnant of a supernova which exploded in the year 1054.
		In fact, the key to a pulsar is the combination of the extraordinary magnetic field and the rotation of a neutron star.
		The center image portrays the pulsar "flash" as it would be seen from Earth given the pulsar's head-on orientation.
	science.nasa.gov /newhome/help/tutorials/pulsar.htm (710 words)

	GSFC Press Release 00-98
		The pulsar possesses unusual properties that may force scientists to reconsider how pulsars are created and evolve.
		This pulsar, in the supernova remnant Kes 75, is about 300 years younger than the second-youngest pulsar, the Crab, which scientists have long considered to be the archetypal young pulsar.
		Yet, compared to the Crab, the Kes 75 pulsar spins ten times more slowly; it is slowing down at a rate ten times faster; and it has a magnetic field that is ten times greater -- all unexpected findings that may cause scientists to rethink the birth properties and evolution of pulsars.
	www.gsfc.nasa.gov /news-release/releases/2000/00-98.htm (883 words)

	Pulsars
		The "pulses" of high-energy radiation we see from a pulsar are due to a misalignment of the neutron star's rotation axis and its magnetic axis.
		Pulsars accelerate particles to tremendous energies in their "magnetospheres", the name for the region which is dominated by the neutron star's incredibly strong magnetic field.
		Pulsars seen this way, whether in the radio, optical, X-ray, or gamma-ray, are often referred to as "spin-powered pulsars," because the ultimate source of energy comes from the gradual slowing down of the neutron star rotation.
	imagine.gsfc.nasa.gov /docs/science/know_l2/pulsars.html (1039 words)

	Enhanced Optical Emission From Crab Pulsar
		A correlation between optical and giant radio pulse emission from the Crab pulsar was detected.
		A broad consensus does exist: that the luminosity is powered by the rotation of the pulsar, that the pulsed radio signal comes from a coherent process, and that the optical–to–x-ray emission is incoherent synchrotron radiation, whereas the γ-ray emission is curvature radiation.
		One suggestion is that the precursor represents emission from the pulsar polar cap region near the neutron star surface, similar to the radio emission from most pulsars, and that the other features come from higher in the magnetosphere.
	www.ing.iac.es:8080 /PR/SH/SH2003/triffid.html (869 words)

	The Pulsar Powered Crab
		The core of the star collapsed to form a rotating neutron star or pulsar, one of the most exotic objects known to 20th century astronomy.
		Like a cosmic lighthouse, the rotating Crab pulsar generates beams of radio, visible, x-ray and gamma-ray energy which, as the name suggests, produce pulses as they sweep across our view.
		Highlights of this HST Crab "movie" show wisps of material moving away from the pulsar at half the speed of light, a scintillating halo, and an intense knot of emission dancing, sprite-like, above the pulsar's pole.
	www.astronet.ru /db/xware/msg/1161696 (225 words)

	HubbleSite - Hubble Astronomers Unveil "Crab Nebula - The Movie" - 5/30/1996
		Probing the mysterious heart of the Crab Nebula, the tattered remains of an exploding star, astronomers have found this object to be even more dynamic than previously understood.
		The sequence of pictures is giving astronomers a remarkable look at the dynamic relationship between the tiny Crab pulsar — the collapsed core of the exploding star — and the vast nebula of dust and gas that it powers.
		The Crab pulsar is the star on the left [white dot] near the center of the frame.
	hubblesite.org /newscenter/newsdesk/archive/releases/1996/22 (159 words)

	M1 The Crab Nebula
		The Crab Nebula is the aftermath of a star that exploded almost 1,000 years ago.
		The Crab Nebula was discovered in 1731 by the English physician and amateur astronomer John Bevis.
		Thus, the Crab Nebula is notable in that it is the object that prompted Messier to produce his famous list of Messier objects.
	members.cox.net /sidleach/m1.htm (740 words)

	Messier Object 1
		The Crab Nebula is the most famous and conspicuous known supernova remnant, the expanding cloud of gas created in the explosion of a star as supernova which was observed in the year 1054 AD.
		These striking properties of the Crab Nebula in the visible light are equally conspicuous in the Palomar images post-processed by David Malin of the Anglo Australian Observatory, and in Paul Scowen's image obtained on Mt. Palomar.
		Measurements during lunar occultations of the Crab Nebula on July 5, 1964, and repeated in 1974 and 1975, demonstrated that the X-rays come from a region at least 2 arc minutes in size, and the energy emitted in X-rays by the Crab nebula is about 100 times more than that emitted in the visual light.
	www.obspm.fr /messier/m/m001.html (2040 words)

	Crab Nebula Info
		This is because the Geminga pulsar is located at a distance 500 ly from Earth while the Crab is 6300 ly from Earth.
		The Crab was the first x-ray source outside of our solar system to be identified with an optical object (Mitton, S. This photo shows the rings of the Crab which are made of highly energized particles that have been thrown from the spinning pulsar.
		Though it is not apparent from the size of this image, the Crab is nearly 50% larger in the radio portion of the spectrum then the optical portion.
	home.cc.umanitoba.ca /~umhoepp3/Crab_Nebula_Info.html (2734 words)

	ScienceDaily: Young Pulsar Reveals Clues To Supernova
		The properties of this pulsar, a neutron star rotating 15 times a second, will enable scientists to better understand how neutron stars are formed in the seconds just before a supernova explosion, and how they pump energy into the space around them for thousands of years after the explosion.
		Murray explained that the 3C 58 pulsar, which is now rotating at about half the rate of the Crab pulsar, is rotating almost as fast as it was when it was formed.
		Astronomers Discover "Bulls-Eye" Pulsar In Supernova Remnant (June 26, 2002) -- Astronomers from the University of Massachusetts and Columbia University have found the "bulls-eye" pulsar in a bright ring of high-energy particles in a distant supernova remnant.
	www.sciencedaily.com /releases/2001/09/010907081012.htm (1834 words)

	[No title]
		Lord Rosse named the nebula the "Crab" in 1844 because its tentacle-like structure resembled the legs of the crustacean.
		Called the Crab Pulsar, it is among the first pulsars discovered, and is the fastest and most energetic pulsar formed from a supernova explosion.
		The Crab Pulsar acts as a celestial power station, generating enough energy to keep the entire nebula radiating over almost the whole electromagnetic spectrum.
	www2.inow.com /~crabneb/crabhis.htm (966 words)

	APOD: 2002 September 20 - The Crab Nebula Pulsar Shrugs (Site not responding. Last check: 2007-10-29)
		APOD: 2002 September 20 - The Crab Nebula Pulsar Shrugs
		The expulsion of wisps of hot gas at high speeds appears to be at least part of the answer.
		The dot at the very center is the hot pulsar spinning 30 times per second.
	antwrp.gsfc.nasa.gov /apod/ap020920.html (150 words)

	Neutron Stars and Pulsars - Introduction
		Pulsars were first discovered in late 1967 by graduate student Jocelyn Bell Burnell as radio sources that blink on and off at a constant frequency.
		Pulsars are spinning neutron stars that have jets of particles moving almost at the speed of light streaming out above their magnetic poles.
		Neutron stars for which we see such pulses are called "pulsars", or sometimes "spin-powered pulsars," indicating that the source of energy is the rotation of the neutron star.
	imagine.gsfc.nasa.gov /docs/science/know_l1/pulsars.html (747 words)

	SPACE.com -- Smallest Deep Space Structures Detected, Study Claims
		It is known as the Crab Pulsar because it anchors a cloudy batch of gas in space called the
		The pulsar, an aged corpse of a star that exploded centuries ago, Earth time, is about 6,000 light-years away.
		The Crab Nebula is the result of a star that exploded on July 4, 1054 and was recorded by Chinese astronomers.
	www.space.com /scienceastronomy/pulsar_beachball_030312.html (601 words)

	Young pulsar reveals clues to supernova
		The 3C58 pulsar is rotating almost as fast as it was when it was formed.
		In contrast, the Crab pulsar was formed spinning much more rapidly and has slowed to about half its initial speed.
		Conventional theory has assumed that all pulsars were like the Crab, but the observations of 3C58 have cast doubt on that assumption.
	www.researchmatters.harvard.edu /story.php?article_id=302 (281 words)

	Crab pulsar Comparison Table (Site not responding. Last check: 2007-10-29)
		An object discovered at Cambridge University in 1967 which has the mass of a star and a radius no larger than that of Earth and which emits radio pulses with a very high degree of regularity (periods range from 0.03 s for the youngest to more than 3 s for the oldest).
		All pulsars are characterized by the general properties of dispersion, periodicity, and short duty cycle.
		Pulsars are believed to be rotating, magnetic (surface magnetic fields of 10
	www.site.uottawa.ca:4321 /astronomy/Crabpulsar_table.html (156 words)

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