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Sergei Kopeikin is a USSR-born theoretical physicist and astronomer presently living and working in the United States, where he holds the position of Professor of Physics at the University of Missouri in Columbia, Missouri. He specializes in the theoretical and experimental study of gravity and general relativity. He is also an expert in the field of the astronomical reference frames and time metrology. His general relativistic theory of the Post-Newtonian reference frames which he had worked out along with Victor A. Brumberg, was adopted in 2000 by the resolutions of the International Astronomical Union as a standard for reduction of ground-based astronomical observation. A computer program Tempo2 used to analyze radio observations of pulsars, includes several effects predicted by S. Kopeikin that are important for measuring parameters of the binary pulsars, for testing general relativity, and for detection of gravitational waves of ultra-low frequency. Sergei Kopeikin has worked out a complete post-Newtonian theory of equations of motion of N extended bodies in scalar-tensor theory of gravity with all mass and spin multipole moments of arbitrary order and derived the Lagrangian of the relativistic N-body problem.
Messier 62 or M62, also known as NGC 6266, is a globular cluster of stars in the south of the equatorial constellation of Ophiuchus. It was discovered in 1771 by Charles Messier, then added to his catalogue eight years later.
47 Tucanae, or 47 Tuc is a globular cluster located in the constellation Tucana. It is about 4.45 ± 0.01 kpc (15,000 ± 33 ly) away from Earth, and 120 light years in diameter. 47 Tuc can be seen with the naked eye, with an apparent magnitude of 4.1. It appears about 44 arcminutes across including its far outreaches. Due to its far southern location, 18° from the south celestial pole, it was not catalogued by European astronomers until the 1750s, when the cluster was first identified by Nicolas-Louis de Lacaille from South Africa.
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 Italian radio astronomer Marta Burgay during a high-latitude pulsar survey.
The Hulse–Taylor binary is a binary star system composed of a neutron star and a pulsar which orbit around their common center of mass. It is the first binary pulsar ever discovered.
PSR B0329+54 is a pulsar approximately 3,460 light-years away in the constellation of Camelopardalis. It completes one rotation every 0.71452 seconds and is approximately 5 million years old.
PSR B1828-11 is a pulsar approximately 10,000 light-years away in the constellation of Scutum. The star exhibits variations in the timing and shape of its pulses: this was at one stage interpreted as due to a possible planetary system in orbit around the pulsar, though the model required an anomalously large second period derivative of the pulse times. The planetary model was later discarded in favour of precession effects as the planets could not cause the observed shape variations of the pulses. While the generally accepted model is that the pulsar is a neutron star undergoing free precession, a model has been proposed that interprets the pulsar as a quark star undergoing forced precession due to an orbiting "quark planet". The entry for the pulsar on SIMBAD lists this hypothesis as being controversial.
PSR J0855-4644 is a pulsar in the constellation Vela, and could be associated with supernova remnant RX J0852.0-4622 which may have exploded about 1200 years ago.
PSR J1302−6350 is a pulsar and member of an eclipsing binary star system with the blue O9.5Ve-class star LS 2883. The pair has an eccentric orbit that is inclined to the line of sight from Earth by about 36°, leading to a 40-day-long eclipse each time the pulsar passes behind the star. The pulsar has a period of about 48 ms and a luminosity of 8.3 × 1035 erg/s. It emits very high energy gamma rays that vary on a time scale of several days.
PSR J1903+0327 is a millisecond pulsar in a highly eccentric binary orbit.
NGC 1553 is a prototypical lenticular galaxy in the constellation Dorado. It is the second brightest member of the Dorado Group of galaxies. British astronomer John Herschel discovered NGC 1553 on December 5, 1834 using an 18.7 inch reflector.
NGC 7424 is a barred spiral galaxy located 37.5 million light-years away in the southern constellation Grus. Its size makes it similar to our own galaxy, the Milky Way. It is called a "grand design" galaxy because of its well defined spiral arms. One supernova and two ultraluminous X-ray sources have been discovered in NGC 7424.
PSR J0437−4715 is a pulsar. Discovered in the Parkes 70 cm survey, it remains the closest and brightest millisecond pulsar (MSP) known. The pulsar rotates about its axis 173.7 times per second and therefore completes a rotation every 5.75 milliseconds. It emits a searchlight-like radio beam that sweeps past the Earth each time it rotates. Currently the most precisely located object outside of the Solar System, PSR J0437-4715 is 156.3 parsecs or 509.8 light-years distant.
A pulsar timing array (PTA) is a set of pulsars which is analysed to search for correlated signatures in the pulse arrival times. There are many applications for pulsar timing arrays. The best known is the use of an array of millisecond pulsars to detect and analyse gravitational waves. Such a detection would result from a detailed investigation of the correlation between arrival times of pulses emitted by the millisecond pulsars as a function of the pulsars' angular separations.
PSR J0108−1431 is a solitary pulsar located at a distance of about 130 parsecs (424 light-years) in the constellation Cetus. This pulsar was discovered in 1994 during the Parkes Southern Pulsar Survey. It is considered a very old pulsar with an estimated age of 166 million years and a rotation period of 0.8 seconds. The rotational energy being generated by the spin-down of this pulsar is 5.8 × 1023 W and the surface magnetic field is 2.5 × 107 T. As of 2008, it is the second faintest known pulsar.
RRAT J1819-1458 is a Milky Way neutron star and the best studied of the class of rotating radio transients (RRATs) first discovered in 2006.
The International Pulsar Timing Array (IPTA) is a multi-institutional, multi-telescope collaboration comprising the European Pulsar Timing Array (EPTA), the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), the Parkes Pulsar Timing Array (PPTA) in Australia, and the Indian Pulsar Timing Array Project (InPTA). The goal of the IPTA is to detect ultra-low-frequency gravitational waves, such as from mergers of supermassive black holes, using an array of approximately 30 pulsars. This goal is shared by each of the participating institutions, but they have all recognized that their goal will be achieved more quickly by combining their respective efforts and resources.
ν Octantis, Latinised as Nu Octantis, is a spectroscopic binary star in the constellation Octans with a period around 2.9 years. Its apparent magnitude is 3.73. Located around 21.20 parsecs (69.1 ly) distant, the primary is an orange giant of spectral type K1III, a star that has used up its core hydrogen and has expanded. The secondary star is likely either a red dwarf or a white dwarf, from its relatively low mass.
Ingrid Stairs is a Canadian astronomer currently based at the University of British Columbia. She studies pulsars and their companions as a way to study binary pulsar evolution, pulsar instrumentation and polarimetry, and Fast Radio Bursts (FRBs). She was awarded the 2017 Rutherford Memorial Medal for physics of the Royal Society of Canada, and was elected as a Fellow of the American Physical Society in 2018.
PSR J1141−6545 is a pulsar in the constellation of Musca. Located at 11h 41m 07.02s −65° 45′ 19.1″, it is a binary pair composed of a white dwarf star orbiting a pulsar. Because of this unusual configuration and the close proximity of the two stars it has been used to test several of Einstein's theories.
References
- ↑ "Tempo".
- ↑ "Tempo Reference Manual".
- ↑ G. Hobbs; R. Edwards; R. Manchester (2006). "TEMPO2, a new pulsar timing package. I: Overview". Monthly Notices of the Royal Astronomical Society. 369 (2): 655–672. arXiv: astro-ph/0603381 . Bibcode:2006MNRAS.369..655H. doi:10.1111/j.1365-2966.2006.10302.x. S2CID 9100723.
- ↑ R. T. Edwards; G. B. Hobbs; R. N. Manchester (2006). "Tempo2, a new pulsar timing package. II: The timing model and precision estimates". Monthly Notices of the Royal Astronomical Society. 372 (4): 1549–1574. arXiv: astro-ph/0607664 . Bibcode:2006MNRAS.372.1549E. doi:10.1111/j.1365-2966.2006.10870.x. S2CID 15470313.