Jerome Kristian

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Jerome Kristian in 1952. Jerome Kristian 1952.jpg
Jerome Kristian in 1952.

Jerome "Jerry" Kristian (born June 5, 1933 in Milwaukee, [1] d. June 22, 1996 in Ventura County, California [2] ) was a theoretical and observational cosmologist, and the first to provide observational evidence of quasar host galaxies.

Contents

Kristian began his career in theoretical cosmology but transitioned into observation while working at the Mount Wilson Observatory in the 1960s and 1970s. He helped to pioneer the observational study of pulsars and quasars and participated in the development of the Hubble Space Telescope. He was the first to provide observational support for the now widely accepted theory that quasars are supermassive black holes at the center of distant galaxies. [3]

Education

At the undergraduate level, Kristian attended Shimer College, a small Great Books college then located in Mount Carroll, Illinois. Because of the school's early entrance program, which began in 1950, [4] he was able to enter college before completing high school. He served as editor-in-chief of the school yearbook and graduated with an AB degree in 1953, [5] while he was still 19. After graduating, he attended the University of Texas for specialized study in physics. [6]

On August 27, 1955, Kristian married Mary Jeanes, a fellow Shimer student who had also moved to the University of Texas, in her case to pursue advanced study in Spanish. [6] [7]

For his graduate studies, starting in the fall of 1955, [7] Kristian attended the University of Chicago, receiving his MS in 1956 and his Ph.D. in 1962. [5] His Ph.D. dissertation, entitled "Hydromagnetic Equilibrium of a Fluid Sphere" and supervised by Subrahmanyan Chandrasekhar, was split into three separate papers and published in The Astrophysical Journal in 1963 and 1964. [8]

Career

After graduation, Kristian returned to the University of Texas as an instructor, working there from 1962 to 1964. [8] In 1963, Kristian and his former teacher [9] Rainer K. Sachs coauthored a paper on Observations in Cosmology. In a special editorial note accompanying a reprint of the paper in 2010, George Ellis called it "one of the least appreciated fundamental papers in theoretical cosmology." [9] The paper "carries out the project of showing how to determine the spacetime structure directly from astronomical observations in the generic General Relativity case, i.e without assuming any preconceived geometry for the universe, using a power series in distance from the origin of observation." [10] 1963 also saw the publication of a key work by Boris Trakhtenbrot, Algorithms and Automatic Computing Machines, which Kristian had cotranslated with James McCawley and Samuel Schmitt. [11]

After leaving the University of Texas, Kristian taught briefly at the University of Wisconsin, but soon moved on to California where he worked at the Mount Wilson Observatory, first as a fellow from 1966 to 1968, and thereafter as a full member of the observatory. The move heralded a shift in his interests from theory to observation, and Kristian published approximately 40 papers in observational astronomy during the 1960s and 1970s. [8] His work, chiefly done in collaboration with Allan Sandage and James Westphal, focused on the optical identification of radio-wave sources such as pulsars and quasars. [8] Westphal recalled the partnership "I was the guy who ran the equipment. Allan was the guy who decided what was good to do. And Jerry was the guy who was supposed to be analyzing the data."

During this period, Westphal and Kristian conducted groundbreaking work on the use of silicon target (S-T) and silicon intensified target (SIT) detectors in cameras, as well as CCD detectors. [8] This work led to a number of key discoveries, and also laid the groundwork for the Hubble Space Telescope; Westphal and Kristian began working in the Planetary Camera Team of the Hubble program in 1974. [12] Kristian worked on the Hubble program while also continuing a steady program of ground-based observations, leading to publications on supermassive galactic nuclei and gravitational lensing. [12] He continued to work actively in these fields until his death.

In 1973, Kristian photographed 26 low-redshift quasars and confirmed for the first time the presence of optical "fuzz" around them, indicating galaxies which were too faint to be identified directly. [13] Kristian's observations provided the first observational support for the theory, first advanced by quasar co-discoverer Maarten Schmidt, that quasars were located at the center of extremely distant galaxies. His work on quasar host galaxies laid the groundwork for what later became a very active field of study. [14]

In discussing Cygnus X1 with the press in the early 1970s, Kristian had described himself as an "ultra-conservative" on the question of black holes. [15] However, with the publications of his team's findings together with those of another team at Caltech in 1978, Kristian publicly affirmed that black holes were the most plausible explanation: "If there wasn't much mass there, then we would be seeing some evidence of the structure coming apart. But there is no evidence of that. So something has to be there, holding it all together." [16]

Death and legacy

On June 22, 1996, Kristian drowned when his ultralight aircraft crashed into the Santa Clara River after clipping a nearby power line. [2] Nearby farmworkers raced to the scene, but Kristian died before they could extract him. [2]

Kristian's death left many projects unfinished, [12] and as a result, he continued to be listed as an author on scientific papers through the year 2000. [17]

Kristian's 1966 paper coauthored with Rainer K. Sachs on Observations in Cosmology was republished in 2010 by General Relativity and Gravitation. [18]

Kristian's explanation of a CCD in terms of regularly-spaced buckets being used to measure rainfall remains widely cited. [19]

Writings

Books

Works cited

Related Research Articles

<span class="mw-page-title-main">Physical cosmology</span> Branch of cosmology which studies mathematical models of the universe

Physical cosmology is a branch of cosmology concerned with the study of cosmological models. A cosmological model, or simply cosmology, provides a description of the largest-scale structures and dynamics of the universe and allows study of fundamental questions about its origin, structure, evolution, and ultimate fate. Cosmology as a science originated with the Copernican principle, which implies that celestial bodies obey identical physical laws to those on Earth, and Newtonian mechanics, which first allowed those physical laws to be understood.

<span class="mw-page-title-main">General relativity</span> Theory of gravitation as curved spacetime

General relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics. General relativity generalises special relativity and refines Newton's law of universal gravitation, providing a unified description of gravity as a geometric property of space and time or four-dimensional spacetime. In particular, the curvature of spacetime is directly related to the energy and momentum of whatever matter and radiation are present. The relation is specified by the Einstein field equations, a system of second order partial differential equations.

<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">Redshift</span> Change of wavelength in photons during travel

In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation. The opposite change, a decrease in wavelength and simultaneous increase in frequency and energy, is known as a blueshift, or negative redshift. The terms derive from the colours red and blue which form the extremes of the visible light spectrum. The main causes of electromagnetic redshift in astronomy and cosmology are the relative motions of radiation sources, which give rise to the relativistic Doppler effect, and gravitational potentials, which gravitationally redshift escaping radiation. All sufficiently distant light sources show cosmological redshift corresponding to recession speeds proportional to their distances from Earth, a fact known as Hubble's law that implies the universe is expanding.

<span class="mw-page-title-main">Extragalactic astronomy</span> Study of astronomical objects outside the Milky Way Galaxy

Extragalactic astronomy is the branch of astronomy concerned with objects outside the Milky Way galaxy. In other words, it is the study of all astronomical objects which are not covered by galactic astronomy.

<span class="mw-page-title-main">Gravitational lens</span> Light bending by mass between source and observer

A gravitational lens is matter, such as a cluster of galaxies or a point particle, that bends light from a distant source as it travels toward an observer. The amount of gravitational lensing is described by Albert Einstein's general theory of relativity with much greater accuracy than Newtonian physics, which treats light as corpuscles travelling at the speed of light.

The following is a timeline of gravitational physics and general relativity.

A non-standard cosmology is any physical cosmological model of the universe that was, or still is, proposed as an alternative to the then-current standard model of cosmology. The term non-standard is applied to any theory that does not conform to the scientific consensus. Because the term depends on the prevailing consensus, the meaning of the term changes over time. For example, hot dark matter would not have been considered non-standard in 1990, but would be in 2010. Conversely, a non-zero cosmological constant resulting in an accelerating universe would have been considered non-standard in 1990, but is part of the standard cosmology in 2010.

Tired light is a class of hypothetical redshift mechanisms that was proposed as an alternative explanation for the redshift-distance relationship. These models have been proposed as alternatives to the models that involve the expansion of the universe. The concept was first proposed in 1929 by Fritz Zwicky, who suggested that if photons lost energy over time through collisions with other particles in a regular way, the more distant objects would appear redder than more nearby ones. Zwicky himself acknowledged that any sort of scattering of light would blur the images of distant objects more than what is seen. Additionally, the surface brightness of galaxies evolving with time, time dilation of cosmological sources, and a thermal spectrum of the cosmic microwave background have been observed—these effects should not be present if the cosmological redshift was due to any tired light scattering mechanism. Despite periodic re-examination of the concept, tired light has not been supported by observational tests and remains a fringe topic in astrophysics.

<span class="mw-page-title-main">Twin Quasar</span> Gravitationally lensed quasar

The Twin Quasar, was discovered in 1979 and was the first identified gravitationally lensed object, not to be confused with the first detection of light deflection in 1919. It is a quasar that appears as two images, a result from gravitational lensing caused by the galaxy YGKOW G1 that is located directly between Earth and the quasar.

<span class="mw-page-title-main">Astrophysical jet</span> Beam of ionized matter flowing along the axis of a rotating astronomical object

An astrophysical jet is an astronomical phenomenon where outflows of ionised matter are emitted as extended beams along the axis of rotation. When this greatly accelerated matter in the beam approaches the speed of light, astrophysical jets become relativistic jets as they show effects from special relativity.

Tests of general relativity serve to establish observational evidence for the theory of general relativity. The first three tests, proposed by Albert Einstein in 1915, concerned the "anomalous" precession of the perihelion of Mercury, the bending of light in gravitational fields, and the gravitational redshift. The precession of Mercury was already known; experiments showing light bending in accordance with the predictions of general relativity were performed in 1919, with increasingly precise measurements made in subsequent tests; and scientists claimed to have measured the gravitational redshift in 1925, although measurements sensitive enough to actually confirm the theory were not made until 1954. A more accurate program starting in 1959 tested general relativity in the weak gravitational field limit, severely limiting possible deviations from the theory.

The expansion of the universe is the increase in distance between gravitationally unbound parts of the observable universe with time. It is an intrinsic expansion; the universe does not expand "into" anything and does not require space to exist "outside" it. To any observer in the universe, it appears that all but the nearest galaxies recede at speeds that are proportional to their distance from the observer, on average. While objects cannot move faster than light, this limitation only applies with respect to local reference frames and does not limit the recession rates of cosmologically distant objects.

<span class="mw-page-title-main">APM 08279+5255</span> Quasar

APM 08279+5255 is a very distant, broad absorption line quasar located in the constellation Lynx. It is magnified and split into multiple images by the gravitational lensing effect of a foreground galaxy through which its light passes. It appears to be a giant elliptical galaxy with a supermassive black hole and associated accretion disk. It possesses large regions of hot dust and molecular gas, as well as regions with starburst activity.

<span class="mw-page-title-main">Gravitational wave</span> Propagating spacetime ripple

Gravitational waves are waves of the intensity of gravity that are generated by the accelerated masses of binary stars and other motions of gravitating masses, and propagate as waves outward from their source at the speed of light. They were first proposed by Oliver Heaviside in 1893 and then later by Henri Poincaré in 1905 as the gravitational equivalent of electromagnetic waves.

<span class="mw-page-title-main">Jürgen Ehlers</span> German physicist

Jürgen Ehlers was a German physicist who contributed to the understanding of Albert Einstein's theory of general relativity. From graduate and postgraduate work in Pascual Jordan's relativity research group at Hamburg University, he held various posts as a lecturer and, later, as a professor before joining the Max Planck Institute for Astrophysics in Munich as a director. In 1995, he became the founding director of the newly created Max Planck Institute for Gravitational Physics in Potsdam, Germany.

In physical cosmology and astronomy, dark energy is an unknown form of energy that affects the universe on the largest scales. Its primary effect is to drive the accelerating expansion of the universe. Assuming that the lambda-CDM model of cosmology is correct, dark energy is the dominant component of the universe, contributing 68% of the total energy in the present-day observable universe while dark matter and ordinary (baryonic) matter contribute 26% and 5%, respectively, and other components such as neutrinos and photons are nearly negligible. Dark energy's density is very low: 6×10−10 J/m3, much less than the density of ordinary matter or dark matter within galaxies. However, it dominates the universe's mass–energy content because it is uniform across space.

<span class="mw-page-title-main">Peter J. Young</span> British astrophysicist

Peter John Young was a British astrophysicist, who made major contributions in theory and observation to extragalactic astronomy and cosmology. During five years at the California Institute of Technology in 1976-1981 he carried out foundational research, including the discovery of the intergalactic medium; the detection of a supermassive black hole in the galaxy M87; detecting the optical counterpart to the first gravitational lens; developing the theory of gravitational microlensing.

References

  1. Who's Who in Frontier Science and Technology. 1st ed. 1984-1985, Chicago 1984, p. 409.
  2. 1 2 3 David R. Baker (1996-06-24). "Pilot Drowned in River After Ultralight Crash". Los Angeles Times. p. B3.
  3. "Quasars may be galactic heart seizures". New Scientist . 1973-01-11. p. 62.
  4. Shimer College. "Shimer College early entrance program". Archived from the original on 2013-06-02. Retrieved 2012-09-30.
  5. 1 2 "Information for Students September 1979" (PDF). p. 77.
  6. 1 2 "Scattered Family". Shimer College Record. Vol. 45, no. 4. October 1953. p. 13.
  7. 1 2 "Mary Alice Jeanes Marries Jerome Kristian at Church". Dallas Morning News . 1955-08-28. p. E-7.
  8. 1 2 3 4 5 Munch 1996, p. 1476.
  9. 1 2 Ellis 2011, p. 331.
  10. Ellis 2011, p. 332.
  11. Trakhtenbrot, Boris A. (1963). Algorithms and Automatic Computing Machines. Gerard Arthus.
  12. 1 2 3 Munch 1996, p. 1477.
  13. J.L. Sérsic (1982). Extragalactic Astronomy: Lecture Notes from Córdoba. Springer. p. 111. ISBN   9789027713216.
  14. Ho 2004, p. xv.
  15. George Alexander (1973-11-21). "Astronomers Report Finding Proof of Space 'Black Hole'". Los Angeles Times [paywalled]. Archived from the original on June 30, 2013. Retrieved 2012-09-30.
  16. George Alexander (1978-05-03). "Galaxy 'Black Hole' Believed Identified". Los Angeles Times [paywalled]. Archived from the original on June 30, 2013.
  17. John Middleditch; Jerome Kristian; et al. (2000). "Rapid photometry of supernova 1987A: a 2.14 ms pulsar?". New Astronomy. 5 (5): 243–283. Bibcode:2000NewA....5..243M. doi:10.1016/s1384-1076(00)00024-5.
  18. Kristian, Jerome; Sachs, Rainer K. (2011). "Golden Oldie: Republication of: Observations in cosmology". General Relativity and Gravitation. 43 (1): 337–358. Bibcode:2011GReGr..43..337K. doi: 10.1007/s10714-010-1114-1 .
  19. Laboratoire Pierre Aigrain. "How a CCD Works". Archived from the original on 2013-07-01. Retrieved 2012-10-01.