Halton Arp
Encyclopedia
Halton Christian Arp is an American
astronomer
. He is known for his 1966 Atlas of Peculiar Galaxies
, which (it was later realized) catalogues many examples of interacting and merging galaxies. Arp is also known as a critic of the Big Bang theory
and for advocating a non-standard cosmology
incorporating intrinsic redshift.
Arp was born March 21, 1927, in New York City
. He has been married three times, has four daughters and four grandchildren. His bachelor's degree
was awarded by Harvard
(1949), and his Ph.D.
by Caltech
(1953). Afterward he became a Fellow of the Carnegie Institution of Washington in 1953, performing research at the Mount Wilson Observatory
and Palomar Observatory
. Arp became a Research Assistant at Indiana University
in 1955, and then in 1957 became a staff member at Palomar Observatory
, where he worked for 29 years. In 1983 he joined the staff of the Max Planck Institute for Astrophysics
in Germany
.
, which was first published in 1966. Arp realized that astronomers understood little about how galaxies change over time, which led him to work on this project. This atlas was intended to provide images that would give astronomers data from which they could study the evolution of galaxies. Arp later used the atlas as evidence in his debate on QSOs.
Based on its citation by other astronomers, Arp's atlas is recognized now as an excellent compilation of interacting and merging galaxies. Many objects in the atlas are primarily referred to by their Arp number. Many of these objects (particularly Arp 220
) are also used as spectral templates for studying high-redshift galaxies.
of the star was measured, it contained a number of unidentifiable spectral line
s that defied all attempts at explanation; John Gatenby Bolton
's suggestion that these were highly redshifted sources was not widely accepted.
In 1963 Maarten Schmidt
found a visible companion to 3C 273. Using the Hale telescope
, Schmidt found the same odd spectra, but was able to demonstrate that it could be explained as the spectrum of hydrogen, shifted by a very large 15.8.% If this was due to the physical motion of the "star", it would represent a speed of 47,000 km/s, far beyond the speed of any known star and defying an obvious explanation. Nor would this explain the huge radio emissions that had led to its original detection.
Schmidt noted that redshift is also associated with the expansion of the universe, as codified in Hubble's law
. If the measured redshift was due to expansion, then the object in question would have to be very far away. In that case, it would have to have an extraordinarily high luminosity
, equally beyond any object seen to date. However, this extreme luminosity would also explain the large radio signal. Schmidt concluded quasars are very distant, very luminous objects.
Schmidt's explanation for the high redshift was not universally accepted at the time. Another explanation that was offered was that it was gravitational redshift
that was being measured; this would require a massive object that would also explain the high luminosities. However, a star large enough to produce the measured redshift would be well beyond the Hayashi limit
. Several other mechanisms were proposed as well, each with their own problems.
One group of these, numbers 1 through 101, were otherwise conventional galaxies that appeared to have small companion objects of unknown origin. In 1967 Arp noted that several of these objects appeared on the list of quasars. In some photographs a quasar is in the foreground of known galaxies, and in others there appeared to be matter bridging the two objects, implying they are very close in space. If they are, and the redshifts were due to Hubble expansion, then both objects should have similar redshifts. However, the galaxies had much smaller redshifts than the quasars. Arp argued that the redshift was not due to Hubble expansion or physical movement of the objects, but must have a non-cosmological or "intrinsic" origin.
Arp also noted that quasars were not evenly spread over the sky, but tended to be more commonly found in positions of small angular separation from certain galaxies. This being the case, they might be in some way related to the galaxies. Arp's hypothesis
is that quasars are local objects ejected from the core of active galactic nuclei (AGN). Nearby galaxies with both strong radio
emission and peculiar morphologies, particularly M87
and Centaurus A
, appeared to support Arp's hypothesis.
In his books, Arp has provided his reasons for believing that the Big Bang
theory itself is wrong, citing his research into quasi-stellar objects
(QSOs). Instead, Arp supports the redshift quantization
theory as an explanation of the redshifts of galaxies.
s and astronomical instrumentation have advanced greatly since then: the Hubble Space Telescope
was launched, multiple 8-10 meter telescopes (such as those at Keck Observatory) have become operational, and detectors such as CCD
s are now more widely employed. These new telescopes and new instrumentation have been utilized to examine QSOs further. QSOs are now generally accepted to be very distant galaxies with high redshifts. Moreover, many imaging surveys, most notably the Hubble Deep Field
, have found many high-redshift objects that are not QSOs but that appear to be normal galaxies like those found nearby. Moreover, the spectra
of the high-redshift galaxies, as seen from X-ray
to radio
wavelengths, match the spectra of nearby galaxies (particularly galaxies with high levels of star formation
activity but also galaxies with normal or extinguished star formation activity) when corrected for redshift effects. As more recent experiments have expanded the amount of collected data by orders of magnitude, it has become increasingly simple to test Arp's postulates directly. A recent study stated that:
Nonetheless, Arp has not wavered from his stand against the Big Bang
and still publishes articles stating his contrary view in both popular and scientific literature, frequently collaborating with Geoffrey Burbidge
(until his death in 2010) and Margaret Burbidge
.
by the American Astronomical Society
, a prize "normally awarded annually for a significant contribution to observational or theoretical astronomy during the five years preceding the award."
In the same year, Arp was awarded the Newcomb Cleveland Prize
for his address, "The Stellar Content of Galaxies", read before a joint session of the American Astronomical Society and AAAS Section D.
In 1984, he was awarded the Alexander von Humboldt Senior Scientist Award
.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
astronomer
Astronomer
An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...
. He is known for his 1966 Atlas of Peculiar Galaxies
Atlas of Peculiar Galaxies
The Atlas of Peculiar Galaxies is a catalog of peculiar galaxies produced by Halton Arp. A total of 338 galaxies are presented in the atlas, which was originally published in 1966 by the California Institute of Technology....
, which (it was later realized) catalogues many examples of interacting and merging galaxies. Arp is also known as a critic of the Big Bang theory
Big Bang
The Big Bang theory is the prevailing cosmological model that explains the early development of the Universe. According to the Big Bang theory, the Universe was once in an extremely hot and dense state which expanded rapidly. This rapid expansion caused the young Universe to cool and resulted in...
and for advocating a non-standard cosmology
Non-standard cosmology
A non-standard cosmology is any physical cosmological model of the universe that has been, or still is, proposed as an alternative to the big bang model of standard physical cosmology...
incorporating intrinsic redshift.
Biography
New York City
New York is the most populous city in the United States and the center of the New York Metropolitan Area, one of the most populous metropolitan areas in the world. New York exerts a significant impact upon global commerce, finance, media, art, fashion, research, technology, education, and...
. He has been married three times, has four daughters and four grandchildren. His bachelor's degree
Bachelor's degree
A bachelor's degree is usually an academic degree awarded for an undergraduate course or major that generally lasts for three or four years, but can range anywhere from two to six years depending on the region of the world...
was awarded by Harvard
Harvard College
Harvard College, in Cambridge, Massachusetts, is one of two schools within Harvard University granting undergraduate degrees...
(1949), and his Ph.D.
Doctor of Philosophy
Doctor of Philosophy, abbreviated as Ph.D., PhD, D.Phil., or DPhil , in English-speaking countries, is a postgraduate academic degree awarded by universities...
by Caltech
California Institute of Technology
The California Institute of Technology is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering...
(1953). Afterward he became a Fellow of the Carnegie Institution of Washington in 1953, performing research at the Mount Wilson Observatory
Mount Wilson Observatory
The Mount Wilson Observatory is an astronomical observatory in Los Angeles County, California, United States. The MWO is located on Mount Wilson, a 5,715 foot peak in the San Gabriel Mountains near Pasadena, northeast of Los Angeles...
and Palomar Observatory
Palomar Observatory
Palomar Observatory is a privately owned observatory located in San Diego County, California, southeast of Pasadena's Mount Wilson Observatory, in the Palomar Mountain Range. At approximately elevation, it is owned and operated by the California Institute of Technology...
. Arp became a Research Assistant at Indiana University
Indiana University Bloomington
Indiana University Bloomington is a public research university located in Bloomington, Indiana, in the United States. IU Bloomington is the flagship campus of the Indiana University system. Being the flagship campus, IU Bloomington is often referred to simply as IU or Indiana...
in 1955, and then in 1957 became a staff member at Palomar Observatory
Palomar Observatory
Palomar Observatory is a privately owned observatory located in San Diego County, California, southeast of Pasadena's Mount Wilson Observatory, in the Palomar Mountain Range. At approximately elevation, it is owned and operated by the California Institute of Technology...
, where he worked for 29 years. In 1983 he joined the staff of the Max Planck Institute for Astrophysics
Max Planck Institute for Astrophysics
The Max Planck Institute for Astrophysics is a Max Planck Institute, located in Garching, near Munich, Bavaria, Germany. It was founded as Max Planck Institute for Physics and Astrophysics in 1958 and split up into the Max Planck Institute for Astrophysics and the Max Planck Institute for Physics...
in Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
.
The Atlas of Peculiar Galaxies
Arp compiled a catalog of unusual galaxies titled Atlas of Peculiar GalaxiesAtlas of Peculiar Galaxies
The Atlas of Peculiar Galaxies is a catalog of peculiar galaxies produced by Halton Arp. A total of 338 galaxies are presented in the atlas, which was originally published in 1966 by the California Institute of Technology....
, which was first published in 1966. Arp realized that astronomers understood little about how galaxies change over time, which led him to work on this project. This atlas was intended to provide images that would give astronomers data from which they could study the evolution of galaxies. Arp later used the atlas as evidence in his debate on QSOs.
Based on its citation by other astronomers, Arp's atlas is recognized now as an excellent compilation of interacting and merging galaxies. Many objects in the atlas are primarily referred to by their Arp number. Many of these objects (particularly Arp 220
Arp 220
Arp 220 is the result of a collision between two galaxies which are now in the process of merging. Located 250 million light-years away in the constellation Serpens, it is the 220th object in Halton Arp's Atlas of Peculiar Galaxies.-Features:...
) are also used as spectral templates for studying high-redshift galaxies.
Characterizing quasars
During the 1950s a number of bright radio sources had been discovered that did not appear to have an optical counterpart. In 1960 one of these sources, 3C 48, was found to be associated with what appeared to be a small blue star. However, when the spectrumSpectrum
A spectrum is a condition that is not limited to a specific set of values but can vary infinitely within a continuum. The word saw its first scientific use within the field of optics to describe the rainbow of colors in visible light when separated using a prism; it has since been applied by...
of the star was measured, it contained a number of unidentifiable spectral line
Spectral line
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from a deficiency or excess of photons in a narrow frequency range, compared with the nearby frequencies.- Types of line spectra :...
s that defied all attempts at explanation; John Gatenby Bolton
John Gatenby Bolton
This article is on the astronomer John Bolton. For other people named "John Bolton," see John Bolton .John Gatenby Bolton was a British-Australian astronomer from Sheffield, England. He attended King Edward VII School , followed by Trinity College, Cambridge from 1940 to 1942, during which time...
's suggestion that these were highly redshifted sources was not widely accepted.
In 1963 Maarten Schmidt
Maarten Schmidt
Maarten Schmidt is a Dutch astronomer who measured the distances of quasars.Born in Groningen, The Netherlands, Schmidt studied with Jan Hendrik Oort. He earned his Ph.D. degree from Leiden Observatory in 1956....
found a visible companion to 3C 273. Using the Hale telescope
Hale telescope
The Hale Telescope is a , 3.3 reflecting telescope at the Palomar Observatory in California, named after astronomer George Ellery Hale. With funding from the Rockefeller Foundation, he orchestrated the planning, design, and construction of the observatory, but did not live to see its commissioning...
, Schmidt found the same odd spectra, but was able to demonstrate that it could be explained as the spectrum of hydrogen, shifted by a very large 15.8.% If this was due to the physical motion of the "star", it would represent a speed of 47,000 km/s, far beyond the speed of any known star and defying an obvious explanation. Nor would this explain the huge radio emissions that had led to its original detection.
Schmidt noted that redshift is also associated with the expansion of the universe, as codified in Hubble's law
Hubble's law
Hubble's law is the name for the astronomical observation in physical cosmology that: all objects observed in deep space are found to have a doppler shift observable relative velocity to Earth, and to each other; and that this doppler-shift-measured velocity, of various galaxies receding from...
. If the measured redshift was due to expansion, then the object in question would have to be very far away. In that case, it would have to have an extraordinarily high luminosity
Luminosity
Luminosity is a measurement of brightness.-In photometry and color imaging:In photometry, luminosity is sometimes incorrectly used to refer to luminance, which is the density of luminous intensity in a given direction. The SI unit for luminance is candela per square metre.The luminosity function...
, equally beyond any object seen to date. However, this extreme luminosity would also explain the large radio signal. Schmidt concluded quasars are very distant, very luminous objects.
Schmidt's explanation for the high redshift was not universally accepted at the time. Another explanation that was offered was that it was gravitational redshift
Gravitational redshift
In astrophysics, gravitational redshift or Einstein shift describes light or other forms of electromagnetic radiation of certain wavelengths that originate from a source that is in a region of a stronger gravitational field that appear to be of longer wavelength, or redshifted, when seen or...
that was being measured; this would require a massive object that would also explain the high luminosities. However, a star large enough to produce the measured redshift would be well beyond the Hayashi limit
Hayashi limit
Hayashi limit is a constraint upon the maximum radius of a star for a given mass. When a star is fully within hydrostatic equilibrium—a condition where the inward force of gravity is matched by the outward pressure of the gas—then the star can not exceed the radius defined by the...
. Several other mechanisms were proposed as well, each with their own problems.
Arp's suggestion
In 1966, Arp published the Atlas of Peculiar Galaxies, which contained photographs of 338 nearby galaxies that didn't fall into any of the classic categories of galaxy shapes. His goal was to produce a selection that modellers could then use in order to test theories of galactic formation. By testing against the collection, one could quickly see how well a particular theory stood up.One group of these, numbers 1 through 101, were otherwise conventional galaxies that appeared to have small companion objects of unknown origin. In 1967 Arp noted that several of these objects appeared on the list of quasars. In some photographs a quasar is in the foreground of known galaxies, and in others there appeared to be matter bridging the two objects, implying they are very close in space. If they are, and the redshifts were due to Hubble expansion, then both objects should have similar redshifts. However, the galaxies had much smaller redshifts than the quasars. Arp argued that the redshift was not due to Hubble expansion or physical movement of the objects, but must have a non-cosmological or "intrinsic" origin.
Arp also noted that quasars were not evenly spread over the sky, but tended to be more commonly found in positions of small angular separation from certain galaxies. This being the case, they might be in some way related to the galaxies. Arp's hypothesis
Hypothesis
A hypothesis is a proposed explanation for a phenomenon. The term derives from the Greek, ὑποτιθέναι – hypotithenai meaning "to put under" or "to suppose". For a hypothesis to be put forward as a scientific hypothesis, the scientific method requires that one can test it...
is that quasars are local objects ejected from the core of active galactic nuclei (AGN). Nearby galaxies with both strong radio
Radio
Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...
emission and peculiar morphologies, particularly M87
Messier 87
Messier 87 is a supergiant elliptical galaxy. It was discovered in 1781 by the French astronomer Charles Messier, who cataloged it as a nebulous feature. The second brightest galaxy within the northern Virgo Cluster, it is located about 16.4 million parsecs from Earth...
and Centaurus A
Centaurus A
Centaurus A is a prominent galaxy in the constellation of Centaurus. There is considerable debate in the literature regarding the galaxy's fundamental properties such as its Hubble type and distance...
, appeared to support Arp's hypothesis.
In his books, Arp has provided his reasons for believing that the Big Bang
Big Bang
The Big Bang theory is the prevailing cosmological model that explains the early development of the Universe. According to the Big Bang theory, the Universe was once in an extremely hot and dense state which expanded rapidly. This rapid expansion caused the young Universe to cool and resulted in...
theory itself is wrong, citing his research into quasi-stellar objects
Quasar
A quasi-stellar radio source is a very energetic and distant active galactic nucleus. Quasars are extremely luminous and were first identified as being high redshift sources of electromagnetic energy, including radio waves and visible light, that were point-like, similar to stars, rather than...
(QSOs). Instead, Arp supports the redshift quantization
Redshift quantization
Redshift quantization is the hypothesis that the redshifts of cosmologically distant objects tend to cluster around multiples of some particular value...
theory as an explanation of the redshifts of galaxies.
Critics
Arp originally proposed his theories in the 1960s; however, telescopeTelescope
A telescope is an instrument that aids in the observation of remote objects by collecting electromagnetic radiation . The first known practical telescopes were invented in the Netherlands at the beginning of the 1600s , using glass lenses...
s and astronomical instrumentation have advanced greatly since then: the Hubble Space Telescope
Hubble Space Telescope
The Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...
was launched, multiple 8-10 meter telescopes (such as those at Keck Observatory) have become operational, and detectors such as CCD
Charge-coupled device
A charge-coupled device is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value. This is achieved by "shifting" the signals between stages within the device one at a time...
s are now more widely employed. These new telescopes and new instrumentation have been utilized to examine QSOs further. QSOs are now generally accepted to be very distant galaxies with high redshifts. Moreover, many imaging surveys, most notably the Hubble Deep Field
Hubble Deep Field
The Hubble Deep Field is an image of a small region in the constellation Ursa Major, constructed from a series of observations by the Hubble Space Telescope. It covers an area 2.5 arcminutes across, two parts in a million of the whole sky, which is equivalent in angular size to a 65 mm tennis...
, have found many high-redshift objects that are not QSOs but that appear to be normal galaxies like those found nearby. Moreover, the spectra
Spectrum
A spectrum is a condition that is not limited to a specific set of values but can vary infinitely within a continuum. The word saw its first scientific use within the field of optics to describe the rainbow of colors in visible light when separated using a prism; it has since been applied by...
of the high-redshift galaxies, as seen from X-ray
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
to radio
Radio
Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...
wavelengths, match the spectra of nearby galaxies (particularly galaxies with high levels of star formation
Star formation
Star formation is the process by which dense parts of molecular clouds collapse into a ball of plasma to form a star. As a branch of astronomy star formation includes the study of the interstellar medium and giant molecular clouds as precursors to the star formation process and the study of young...
activity but also galaxies with normal or extinguished star formation activity) when corrected for redshift effects. As more recent experiments have expanded the amount of collected data by orders of magnitude, it has become increasingly simple to test Arp's postulates directly. A recent study stated that:
- "... the publicly available data from the Sloan Digital Sky SurveySloan Digital Sky SurveyThe Sloan Digital Sky Survey or SDSS is a major multi-filter imaging and spectroscopic redshift survey using a dedicated 2.5-m wide-angle optical telescope at Apache Point Observatory in New Mexico, United States. The project was named after the Alfred P...
and 2dF QSO redshift survey to test the hypothesis that QSOs are ejected from active galaxies with periodic noncosmological redshifts. For two different intrinsic redshift models, [...] and find there is no evidence for a periodicity at the predicted frequency in log(1+z), or at any other frequency."
Nonetheless, Arp has not wavered from his stand against the Big Bang
Big Bang
The Big Bang theory is the prevailing cosmological model that explains the early development of the Universe. According to the Big Bang theory, the Universe was once in an extremely hot and dense state which expanded rapidly. This rapid expansion caused the young Universe to cool and resulted in...
and still publishes articles stating his contrary view in both popular and scientific literature, frequently collaborating with Geoffrey Burbidge
Geoffrey Burbidge
Geoffrey Ronald Burbidge FRS was an English astronomy professor, most recently at the University of California, San Diego. He was married to astrophysicist Dr. Margaret Burbidge.-Education:...
(until his death in 2010) and Margaret Burbidge
Margaret Burbidge
Eleanor Margaret Burbidge, née Peachey, FRS is a British-born American astrophysicist, noted for original research and holding many administrative posts, including director of the Royal Greenwich Observatory....
.
Notable honors and awards
In 1960, Arp was awarded the Helen B. Warner Prize for AstronomyHelen B. Warner Prize for Astronomy
The Helen B. Warner Prize for Astronomy is awarded annually by the American Astronomical Society to a young astronomer for a significant contribution to observational or theoretical astronomy....
by the American Astronomical Society
American Astronomical Society
The American Astronomical Society is an American society of professional astronomers and other interested individuals, headquartered in Washington, DC...
, a prize "normally awarded annually for a significant contribution to observational or theoretical astronomy during the five years preceding the award."
In the same year, Arp was awarded the Newcomb Cleveland Prize
Newcomb Cleveland Prize
The Newcomb Cleveland Prize of the American Association for the Advancement of Science is annually awarded to author of outstanding scientific paper published in the Research Articles or Reports sections of Science...
for his address, "The Stellar Content of Galaxies", read before a joint session of the American Astronomical Society and AAAS Section D.
In 1984, he was awarded the Alexander von Humboldt Senior Scientist Award
The Humboldt Prize
The Humboldt Prize, also known as the Humboldt Research Award, is an award given by the Alexander von Humboldt Foundation to internationally renowned scientists and scholars, and is currently valued at € 60,000 with the possibility of further support during the prize winner's life. Up to one...
.
See also
- Main : Quasars, Redshifts and ControversiesQuasars, Redshifts and ControversiesQuasars, Redshifts and Controversies is a 1987 book by Halton Arp, an astronomer famous for his Atlas of Peculiar Galaxies . Arp argued that many quasars with otherwise high redshift are somehow linked to close objects such as nearby galaxies...
(ISBN 0-521-36314-4) - List of astronomical topics : QuasarQuasarA quasi-stellar radio source is a very energetic and distant active galactic nucleus. Quasars are extremely luminous and were first identified as being high redshift sources of electromagnetic energy, including radio waves and visible light, that were point-like, similar to stars, rather than...
- CosmologyPhysical cosmologyPhysical cosmology, as a branch of astronomy, is the study of the largest-scale structures and dynamics of the universe and is concerned with fundamental questions about its formation and evolution. For most of human history, it was a branch of metaphysics and religion...
: Non-standard cosmologyNon-standard cosmologyA non-standard cosmology is any physical cosmological model of the universe that has been, or still is, proposed as an alternative to the big bang model of standard physical cosmology...
, Intrinsic redshifts, Redshift quantizationRedshift quantizationRedshift quantization is the hypothesis that the redshifts of cosmologically distant objects tend to cluster around multiples of some particular value...
, Le Sage's theory of gravitationLe Sage's theory of gravitationLe Sage's theory of gravitation is a kinetic theory of gravity originally proposed by Nicolas Fatio de Duillier in 1690 and later by Georges-Louis Le Sage in 1748. The theory proposed a mechanical explanation for Newton's gravitational force in terms of streams of tiny unseen particles impacting...
, Big BangBig BangThe Big Bang theory is the prevailing cosmological model that explains the early development of the Universe. According to the Big Bang theory, the Universe was once in an extremely hot and dense state which expanded rapidly. This rapid expansion caused the young Universe to cool and resulted in... - Other : Helen B. Warner Prize for AstronomyHelen B. Warner Prize for AstronomyThe Helen B. Warner Prize for Astronomy is awarded annually by the American Astronomical Society to a young astronomer for a significant contribution to observational or theoretical astronomy....
Further reading
- Halton Arp, Seeing Red, Aperion (August, 1998) ISBN 0-9683689-0-5
- Halton Arp, Catalogue of Discordant Redshift Associations, Aperion (September 1, 2003) ISBN 0-9683689-9-9
- G. Burbidge, E.M. Burbidge, H.C. Arp, W.M. Napier: Ultraluminous X-ray Sources, High Redshift QSOs and Active Galaxies. Preprint
- Dewey B. Larson, The Universe of Motion, North Pacific Publishers (1984) ISBN 0-913138-11-8
- J. Kanipe, D. Webb The Arp Atlas of Peculiar Galaxies, A Chronicle and Observer's Guide, Willmann-Bell Inc. (2006) ISBN 978-0-943396-76-7
External links
- Halton Arp's Website
- Apeiron, journal web site. (Arp is editorial board member)
- Publications by Halton C. Arp at the Scientific Commons repository
- Atlas of Peculiar Galaxies
- Arp's Catalog of Peculiar Galaxies website
- Detailed review of Seeing Red by Tom Van Flandern
- Electric Politics interview with Halton C. Arp (podcast)
- Astraea Magazine interview with Halton C. Arp (podcast)
- Preface to "The Arp Atlas of Peculiar Galaxies"
- Author's Notes to "The Arp Atlas of Peculiar Galaxies"
- Halton Arp directory page at the IAU
- Oral History interview transcript with Halton Arp 29 July 1975, American Institute of Physics, Niels Bohr Library and Archives