Related Research Articles
A neutron star is the collapsed core of a massive supergiant star, which had a total mass of between 10 and 25 solar masses, possibly more if the star was especially metal-rich. Except for black holes, and some hypothetical objects, neutron stars are the smallest and densest currently known class of stellar objects. Neutron stars have a radius on the order of 10 kilometres (6.2 mi) and a mass of about 1.4 solar masses. They result from the supernova explosion of a massive star, combined with gravitational collapse, that compresses the core past white dwarf star density to that of atomic nuclei.
Astronomy is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, galaxies, and comets. Relevant phenomena include supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation. More generally, astronomy studies everything that originates outside Earth's atmosphere. Cosmology is a branch of astronomy that studies the universe as a whole.
Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The first detection of radio waves from an astronomical object was in 1932, when Karl Jansky at Bell Telephone Laboratories observed radiation coming from the Milky Way. Subsequent observations have identified a number of different sources of radio emission. These include stars and galaxies, as well as entirely new classes of objects, such as radio galaxies, quasars, pulsars, and masers. The discovery of the cosmic microwave background radiation, regarded as evidence for the Big Bang theory, was made through radio astronomy.
A magnetar is a type of neutron star believed to have an extremely powerful magnetic field (∼109 to 1011 T, ∼1013 to 1015 G). The magnetic-field decay powers the emission of high-energy electromagnetic radiation, particularly X-rays and gamma rays. The theory regarding these objects was proposed in 1992 by Robert Duncan and Christopher Thompson. The theory was subsequently developed by Bohdan Paczyński and by its proposers. This theory explained a burst of gamma rays from the Large Magellanic Cloud that had been detected on March 5, 1979, and other less bright bursts from within our galaxy. During the following decade, the magnetar hypothesis became widely accepted as a likely explanation for soft gamma repeaters (SGRs) and anomalous X-ray pulsars (AXPs). In 2020, a fast radio burst (FRB) was detected from a magnetar.
Astrophysics is a science that employs the methods and principles of physics in the study of astronomical objects and phenomena. Among the subjects studied are the Sun, other stars, galaxies, extrasolar planets, the interstellar medium and the cosmic microwave background. Emissions from these objects are examined across all parts of the electromagnetic spectrum, and the properties examined include luminosity, density, temperature, and chemical composition. Because astrophysics is a very broad subject, astrophysicists apply concepts and methods from many disciplines of physics, including classical mechanics, electromagnetism, statistical mechanics, thermodynamics, quantum mechanics, relativity, nuclear and particle physics, and atomic and molecular physics.
A pulsar is a highly magnetized rotating compact star that emits beams of electromagnetic radiation out of its magnetic poles. This radiation can be observed only when a beam of emission is pointing toward Earth, and is responsible for the pulsed appearance of emission. Neutron stars are very dense and have short, regular rotational periods. This produces a very precise interval between pulses that ranges from milliseconds to seconds for an individual pulsar. Pulsars are one of the candidates for the source of ultra-high-energy cosmic rays.
The Crab Pulsar is a relatively young neutron star. The star is the central star in the Crab Nebula, a remnant of the supernova SN 1054, which was widely observed on Earth in the year 1054. Discovered in 1968, the pulsar was the first to be connected with a supernova remnant.
PSR J0737−3039 is the only known double pulsar. It consists of two neutron stars emitting electromagnetic waves in the radio wavelength in a relativistic binary system. The two pulsars are known as PSR J0737−3039A and PSR J0737−3039B. It was discovered in 2003 at Australia's Parkes Observatory by an international team led by the radio astronomer Marta Burgay during a high-latitude pulsar survey.
Bryan Malcolm Gaensler is an Australian astronomer based at the University of Toronto. He studies magnetars, supernova remnants, and magnetic fields. In 2014, he was appointed as Director of the Dunlap Institute for Astronomy & Astrophysics at the University of Toronto, after James R. Graham's departure. He is currently the co-chair of the Canadian 2020 Long Range Plan Committee with Pauline Barmby.
The following outline is provided as an overview of and topical guide to astronomy:
Cornelis A. "Neil" Gehrels was an American astrophysicist specializing in the field of gamma-ray astronomy. He was Chief of the Astroparticle Physics Laboratory at NASA's Goddard Space Flight Center from 1995 until his death, and was best known for his work developing the field from early balloon instruments to today's space observatories such as the NASA Swift mission, for which he was the Principal Investigator. He was leading the WFIRST wide-field infrared telescope forward toward a launch in the mid-2020s. He was a member of the National Academy of Sciences and the American Academy of Arts and Sciences.
WR 104 is a triple star system located about 2,580 parsecs (8,400 ly) from Earth. The primary star is a Wolf–Rayet star, abbreviated as WR, with a B0.5 main sequence star in close orbit and another more distant fainter companion.
A stellar collision is the coming together of two stars caused by stellar dynamics within a star cluster, or by the orbital decay of a binary star due to stellar mass loss or gravitational radiation, or by other mechanisms not yet well understood.
The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) is a consortium of astronomers who share a common goal of detecting gravitational waves via regular observations of an ensemble of millisecond pulsars using the Green Bank and Arecibo radio telescopes. This project is being carried out in collaboration with international partners in the Parkes Pulsar Timing Array in Australia and the European Pulsar Timing Array as part of the International Pulsar Timing Array.
Multi-messenger astronomy is astronomy based on the coordinated observation and interpretation of disparate "messenger" signals. Interplanetary probes can visit objects within the Solar System, but beyond that, information must rely on "extrasolar messengers". The four extrasolar messengers are electromagnetic radiation, gravitational waves, neutrinos, and cosmic rays. They are created by different astrophysical processes, and thus reveal different information about their sources.
GW 170817 was a gravitational wave (GW) signal observed by the LIGO and Virgo detectors on 17 August 2017, originating from the shell elliptical galaxy NGC 4993. The GW was produced by the last minutes of two neutron stars spiralling closer to each other and finally merging, and is the first GW observation which has been confirmed by non-gravitational means. Unlike the five previous GW detections, which were of merging black holes not expected to produce a detectable electromagnetic signal, the aftermath of this merger was also seen by 70 observatories on 7 continents and in space, across the electromagnetic spectrum, marking a significant breakthrough for multi-messenger astronomy. The discovery and subsequent observations of GW 170817 were given the Breakthrough of the Year award for 2017 by the journal Science.
The Dunlap Institute for Astronomy and Astrophysics at the University of Toronto is an astronomical research centre.
Samaya Michiko Nissanke is an astrophysicist, associate professor in gravitational wave and multi-messenger astrophysics, and the spokesperson for the GRAPPA Centre for Excellence in Gravitation and Astroparticle Physics at the University of Amsterdam. She works on gravitational-wave astrophysics and has played a founding role in the emerging field of multi-messenger astronomy. She played a leading role in the discovery paper of the first binary neutron star merger, GW170817, seen in gravitational waves and electromagnetic radiation.
Eleonora Troja is an Italian astrophysicist. In 2017 she led the discovery of X-ray emission from the gravitational wave source GW170817. She is an associate research scientist at University of Maryland, College Park and Goddard Space Flight Center.
In astronomy, an Odd radio circle (ORC) is a very large unexplained astronomical object that, at radio wavelengths, is highly circular and brighter along its edges. As of 27 April 2021, there have been five such objects observed. The observed ORCs are bright at radio wavelengths, but are not visible at visible, infrared or X-ray wavelengths. Three of the ORCs contain optical galaxies in their centers, suggesting that the galaxies might have formed these objects.
References
- ↑ Slezak, Michael (2017-10-16). "Neutron stars collision: Australian science reacts – as it happened". The Guardian. ISSN 0261-3077 . Retrieved 2020-07-02.
- ↑ "2014 Australian Frontiers of Science - participants | Australian Academy of Science". www.science.org.au. Retrieved 2020-07-02.
- 1 2 "Gravitational waves: Australian scientists first to confirm radio signals from two colliding stars". SBS News. Retrieved 2020-07-02.
- 1 2 3 "Women in Astronomy: The Contemporary Women in Astronomy". Observations. Retrieved 2020-07-02.
- ↑ correspondent, Hannah Devlin Science (2017-10-16). "New frontier for science as astronomers witness neutron stars colliding". The Guardian. ISSN 0261-3077 . Retrieved 2020-07-02.
- ↑ October 2017, Steve Spaleta 16. "When Neutron Stars Collide! What the Hubble Telescope and Others Saw (Videos)". Space.com. Retrieved 2020-07-02.
- ↑ "Astronomers may have seen the birth of a black hole for the first time". www.abc.net.au. 2019-01-10. Retrieved 2020-07-02.
- ↑ "Tara Murphy". The Conversation. Retrieved 2020-07-02.
| General | |
|---|---|
| Other | |
