Cyril Hazard

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Cyril Hazard
Born(1928-03-18)18 March 1928
NationalityBritish
Alma mater University of Manchester
Scientific career
FieldsAstrophysics
Doctoral advisor Robert Hanbury Brown


Cyril Hazard is a British astronomer. He is known for revolutionising quasar observation with John Bolton in 1962. His work allowed other astronomers to find redshifts from the emission lines from other radio sources. [1]

Contents

Early work

Cyril Hazard was born on 18th March 1928 in No.6, Flosh Cottages, Cleator, Cumberland. Cyril Hazard grew up in Cleator Moor, Cumberland.[ citation needed ]. He got his doctorate from the University of Manchester, studying under Sir Bernard Lovell and Robert Hanbury Brown. He worked first at Jodrell Bank. [2]

In 1950, radio emission from the Andromeda Galaxy were detected by Robert Hanbury Brown and Hazard at the Jodrell Bank Observatory. [3] [4]

The discovery of quasars

Two radio sources were involved 3C 48 and 3C 273 Measurements taken by Cyril Hazard and John Bolton during one of the occultations using the Parkes Radio Telescope allowed Maarten Schmidt to optically identify the object and obtain an optical spectrum using the 200-inch Hale Telescope on Mount Palomar. This spectrum revealed the same strange emission lines. Schmidt realized that these were actually spectral lines of hydrogen redshifted at the rate of 15.8 percent. This discovery showed that 3C 273 was receding at a rate of 47,000 km/s. [1]

The technique

As the source is occulting behind the moon ( viz. passing behind), Fresnel style diffraction patterns are produced which can be detected by very large radio telescopes and the exact locations calculated. [2]

Memory

The minor planet 9305 Hazard, discovered on 7 October 1986 by Edward "Ted" Bowell, was named after him. [5]

Related Research Articles

<span class="mw-page-title-main">Quasar</span> Active galactic nucleus containing a supermassive black hole

A quasar is an extremely luminous active galactic nucleus (AGN). It is sometimes known as a quasi-stellar object, abbreviated QSO. The emission from an AGN is powered by a supermassive black hole with a mass ranging from millions to tens of billions of solar masses, surrounded by a gaseous accretion disc. Gas in the disc falling towards the black hole heats up and releases energy in the form of electromagnetic radiation. The radiant energy of quasars is enormous; the most powerful quasars have luminosities thousands of times greater than that of a galaxy such as the Milky Way. Quasars are usually categorized as a subclass of the more general category of AGN. The redshifts of quasars are of cosmological origin.

<span class="mw-page-title-main">Timeline of knowledge about galaxies, clusters of galaxies, and large-scale structure</span>

The following is a timeline of galaxies, clusters of galaxies, and large-scale structure of the universe.

<span class="mw-page-title-main">Andromeda Galaxy</span> Barred spiral galaxy in the Local Group

The Andromeda Galaxy is a barred spiral galaxy and is the nearest major galaxy to the Milky Way. It was originally named the Andromeda Nebula and is cataloged as Messier 31, M31, and NGC 224. Andromeda has a D25 isophotal diameter of about 46.56 kiloparsecs (152,000 light-years) and is approximately 765 kpc (2.5 million light-years) from Earth. The galaxy's name stems from the area of Earth's sky in which it appears, the constellation of Andromeda, which itself is named after the princess who was the wife of Perseus in Greek mythology.

<span class="mw-page-title-main">Crab Nebula</span> Supernova remnant in the constellation Taurus

The Crab Nebula 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. The nebula was discovered by English astronomer John Bevis in 1731. It corresponds with a bright supernova recorded by Chinese astronomers in 1054 as a guest star. The nebula was the first astronomical object identified that corresponds with a historically-observed supernova explosion.

An active galactic nucleus (AGN) is a compact region at the center of a galaxy that emits a significant amount of energy across the electromagnetic spectrum, with characteristics indicating that this luminosity is not produced by the stars. Such excess, non-stellar emissions have been observed in the radio, microwave, infrared, optical, ultra-violet, X-ray and gamma ray wavebands. A galaxy hosting an AGN is called an active galaxy. The non-stellar radiation from an AGN is theorized to result from the accretion of matter by a supermassive black hole at the center of its host galaxy.

<span class="mw-page-title-main">3C 273</span> Brightest quasar from Earth located in the constellation Virgo

3C 273 is a quasar located at the center of a giant elliptical galaxy in the constellation of Virgo. It was the first quasar ever to be identified and is the visually brightest quasar in the sky as seen from Earth, with an apparent visual magnitude of 12.9. The derived distance to this object is 749 megaparsecs. The mass of its central supermassive black hole is approximately 886 million times the mass of the Sun.

<span class="mw-page-title-main">Blazar</span> Very compact quasi-stellar radio source

A blazar is an active galactic nucleus (AGN) with a relativistic jet directed very nearly towards an observer. Relativistic beaming of electromagnetic radiation from the jet makes blazars appear much brighter than they would be if the jet were pointed in a direction away from Earth. Blazars are powerful sources of emission across the electromagnetic spectrum and are observed to be sources of high-energy gamma ray photons. Blazars are highly variable sources, often undergoing rapid and dramatic fluctuations in brightness on short timescales. Some blazar jets appear to exhibit superluminal motion, another consequence of material in the jet traveling toward the observer at nearly the speed of light.

<span class="mw-page-title-main">MERLIN</span> Observatory

The Multi-Element Radio Linked Interferometer Network (MERLIN) is an interferometer array of radio telescopes spread across England. The array is run from Jodrell Bank Observatory in Cheshire by the University of Manchester on behalf of UK Research and Innovation.

Dennis Walsh was an English astronomer. He was an early radio astronomer, as well as an optical astronomer. He was best known for his discovery in 1979 of the first example of a gravitational lens, B0957+561, using an optical telescope.

<span class="mw-page-title-main">John Gatenby Bolton</span> British-Australian astronomer

John Gatenby Bolton was a British-Australian astronomer who was fundamental to the development of radio astronomy. In particular, Bolton was integral in establishing that discrete radio sources were either galaxies or the remnants of supernovae, rather than stars. He also played a significant role in the discovery of quasars and the centre of the Milky Way. Bolton served as the inaugural director of the Parkes radio telescope in Australia and established the Owens Valley Radio Observatory in California. Bolton's students held directorships at most of the radio observatories in the world and one was a Nobel Prize winner. Bolton is considered a key figure in the development of astronomy in Australia.

<span class="mw-page-title-main">Lovell Telescope</span> Radio telescope at Jodrell Bank Observatory, Cheshire, England

The Lovell Telescope is a radio telescope at Jodrell Bank Observatory, near Goostrey, Cheshire, in the north-west of England. When construction was finished in 1957, the telescope was the largest steerable dish radio telescope in the world at 76.2 m (250 ft) in diameter; it is now the third-largest, after the Green Bank telescope in West Virginia, United States, and the Effelsberg telescope in Germany. It was originally known as the "250 ft telescope" or the Radio Telescope at Jodrell Bank, before becoming the Mark I telescope around 1961 when future telescopes were being discussed. It was renamed to the Lovell Telescope in 1987 after Sir Bernard Lovell, and became a Grade I listed building in 1988. The telescope forms part of the MERLIN and European VLBI Network arrays of radio telescopes.

<span class="mw-page-title-main">Robert Hanbury Brown</span> British astronomer and physicist

Robert Hanbury Brown, AC FRS was a British astronomer and physicist born in Aruvankadu, India. He made notable contributions to the development of radar and later conducted pioneering work in the field of radio astronomy.

The Narrabri Stellar Intensity Interferometer (NSII) was the first astronomical instrument to measure the diameters of a large number of stars at visible wavelengths. It was designed by Robert Hanbury Brown, who received the Hughes Medal in 1971 for this work. It was built by University of Sydney School of Physics and was located near the town of Narrabri in north-central New South Wales, Australia. Many of the components were constructed in the UK. The design was based on an earlier optical intensity interferometer built by Hanbury Brown and Richard Q. Twiss at Jodrell Bank in the UK. Whilst the original device had a maximum baseline of 10m, the NSII device consisted of a large circular track that allowed the detectors to be separated from 10 to 188m. The NSII operated from 1963 until 1974, and was used to measure the angular diameters of 32 stars.

<span class="mw-page-title-main">SN 1572</span> Supernova in the constellation Cassiopeia

SN 1572, or B Cassiopeiae, was a supernova of Type Ia in the constellation Cassiopeia, one of eight supernovae visible to the naked eye in historical records. It appeared in early November 1572 and was independently discovered by many individuals.

Roger Clifton Jennison worked as a radio astronomer at Jodrell Bank under the guidance of Robert Hanbury Brown. Jennison made a number of discoveries in the field of radio astronomy, including the discovery of the double nature of radio source Cygnus A with M K Das Gupta and the mapping of Cassiopeia A with V Latham.

This is a timeline of Jodrell Bank Observatory.

<span class="mw-page-title-main">NGC 7662</span> Planetary nebula in the constellation Andromeda

NGC 7662 is a planetary nebula located in the northern constellation Andromeda. It is known as the Blue Snowball Nebula, Snowball Nebula, and Caldwell 22. This nebula was discovered October 6, 1784 by the German-born English astronomer William Herschel. In the New General Catalogue it is described as a "magnificent planetary or annular nebula, very bright, pretty small in angular size, round, blue, variable nucleus". The object has an apparent visual magnitude of 8.3 and spans an angular size of 32″ × 28″. Parallax measurements give a distance estimate of 5,730 ± 340 ly (1,757 ± 103 pc).

<span class="mw-page-title-main">CK Vulpeculae</span> 1678 Nova seen in the constellation Vulpecula

CK Vulpeculae is an object whose exact nature is unknown. It was once considered to be the oldest reliably-documented nova. It consists of a compact central object surrounded by a bipolar nebula.

Inventions, innovations and firsts made in the county of Cheshire, in North West England.

<span class="mw-page-title-main">40-foot radio telescope</span> Radio telescope in Green Bank, West Virginia, US

The 40-foot radio telescope at Green Bank Observatory in the U.S. state of West Virginia was constructed in 1961, and started observing a selection of variable radio sources in the same year, completing its observations in 1968. It became the first automated telescope in 1962. It was subsequently used during summer schools, and in 1987 it was repurposed as an educational telescope, as well as continuing to observe radio sources. In 2021 the telescope celebrated its sixtieth anniversary, having been in continuous use since its 1987 restoration, and used by more than 1,500 students.

References

  1. 1 2 "Cyril Hazard | Physics & Astronomy | University of Pittsburgh". www.physicsandastronomy.pitt.edu. Retrieved 26 July 2020.
  2. 1 2 "Parkes and 3C273". www.parkes.atnf.csiro.au. Retrieved 26 July 2020.
  3. Brown, Robert Hanbury; Hazard, Cyril (1950). "Radio-frequency Radiation from the Great Nebula in Andromeda (M.31)". Nature . 166 (4230): 901–902. Bibcode:1950Natur.166..901B. doi:10.1038/166901a0. S2CID   4170236.
  4. Brown, Robert Hanbury; Hazard, Cyril (1951). "Radio emission from the Andromeda nebula". MNRAS . 111 (4): 357–367. Bibcode:1951MNRAS.111..357B. doi: 10.1093/mnras/111.4.357 .
  5. 9305 Hazard

Bibliography