Carl Keenan Seyfert

Carl Keenan Seyfert (February 11, 1911 – June 13, 1960) was an American astronomer. He is best known for his 1943 research paper on high-excitation line emission from the centers of some spiral galaxies, which are named Seyfert galaxies after him. Seyfert's Sextet, a group of galaxies, is also named after him.

Carl Keenan Seyfert
BornFebruary 11, 1911
DiedJune 13, 1960 (aged 49)
Cause of deathAutomobile accident
EducationHarvard University (Ph.D. 1936)
Scientific career
InstitutionsMcDonald Observatory
Mount Wilson Observatory
Case Institute
Dyer Observatory
ThesisStudies of the External Galaxies (1936)
Doctoral advisorHarlow Shapley


Seyfert was born and raised in Cleveland, Ohio, then attended Harvard University, starting in 1929. He earned his B.S. and M.S. degrees in 1933, and his Ph.D. in astronomy in 1936. His thesis was "Studies of the External Galaxies", supervised by Harlow Shapley. The thesis dealt with colors and magnitudes of galaxies.

In 1935 Seyfert married astronomer Muriel Elizabeth Mussels, notable for her contributions to the study of ring nebulae. They had two children, daughter Gail Carol and son Carl Keenan Seyfert, Jr.[1]

In 1936 Seyfert joined the staff of the new McDonald Observatory in Texas, where he helped get the observatory started. He stayed until 1940, working with Daniel M. Popper on the properties of faint B stars and continuing his work on colors in spiral galaxies.

In 1940 Seyfert went to Mount Wilson Observatory as a fellow with the National Research Council. He stayed until 1942, studying a class of active galaxies now called Seyfert galaxies. In 1942 he returned to Cleveland, at Case Institute of Technology, where he taught navigation to military personnel and participated in secret military research. He also carried out some astronomical research at the Warner and Swasey Observatory of the Case Institute.

In 1946 Seyfert joined the faculty of Vanderbilt University in Nashville, Tennessee. The astronomy program at Vanderbilt was very small at the time. The university had only a small observatory, equipped with a 6-inch (150 mm) refractor, and only a modest teaching program. Seyfert worked diligently to improve the teaching program and to raise funds to build a new observatory. Within a few years, he had obtained significant public support from the Nashville community. As the result, the Arthur J. Dyer Observatory with its 24-inch (610 mm) reflector was completed in December 1953. Seyfert became director of the new observatory, a position he held until his death. Seyfert was also the local weatherman for WSM-TV, Nashville's NBC affiliate, during the 1950s.

Seyfert died in an automobile accident in Nashville on June 13, 1960; a residential street near the Dyer Observatory was subsequently renamed "Carl Seyfert Memorial Drive" in his honor.

Contributions to astronomy

Carl Seyfert published many papers in the astronomical literature, on a wide variety of topics in stellar and galactic astronomy, as well as on observing methods and instrumentation.

In 1943 he published a paper on galaxies with bright nuclei that emit light with emission line spectra with characteristically broadened emission lines. The prototype example is Messier 77 (NGC 1068). It is this class of galaxies that is now known as Seyfert galaxies, in his honor.

During his time at the Case Institute, he and Jason John Nassau obtained the first good color images of nebulae and stellar spectra. In 1951 he observed and described a group of galaxies around NGC 6027, now known as Seyfert's Sextet. He was an active innovator in instrumentation, being involved in new techniques such as the astronomical use of photomultiplier tubes and television techniques, and electronically controlled telescope drives.

The lunar crater Seyfert is named in his honor (29.1N, 114.6E, 110 km diameter). The 24-inch (610 mm) telescope at Dyer Observatory was renamed for him.


  • Seyfert, Carl K. (January 1943). "Nuclear Emission in Spiral Nebulae". Astrophysical Journal. 97: 28–40. Bibcode:1943ApJ....97...28S. doi:10.1086/144488.


  1. ^ Frommert, Hartmut (2007). "Seyfert, Carl Keenan". In Hockey, Thomas. The Biographical Encyclopedia of Astronomers. New York: Springer. pp. 1045–1046. doi:10.1007/978-0-387-30400-7_1261. ISBN 978-0-387-31022-0.

External links

Dyer Observatory

The Dyer Observatory, also known as the Arthur J. Dyer Observatory, is an astronomical observatory owned and operated by Vanderbilt University. Built in 1953, it is located in Brentwood, Tennessee, and is the only university facility not located on the main campus in Nashville. The observatory is named after Arthur J. Dyer, who paid for the observatory's 24-foot (7.3 m)-wide dome, and houses a 24-inch (610 mm) reflecting telescope named for astronomer Carl Seyfert. Today, the observatory primarily serves as a teaching tool; its mission is to interest children in the fields of science and engineering. The observatory was listed on the National Register of Historic Places on March 6, 2009.

List of Vanderbilt University people

This is a list of notable current and former faculty members, alumni, and non-graduating attendees of Vanderbilt University in Nashville, Tennessee.

Unless otherwise noted, attendees listed graduated with bachelor's degrees. Names with an asterisk (*) graduated from Peabody College prior to its merger with Vanderbilt.

List of people with craters of the Moon named after them

The following is a list of people whose names were given to craters of the Moon. The list of approved names in the Gazetteer of Planetary Nomenclature maintained by the International Astronomical Union includes the person the crater is named for.

Muriel Mussells Seyfert

Muriel E. Mussells Seyfert (born Muriel Elizabeth Mussells, 3 February 1909 – 9 November 1997) was an American astronomer best known for discovery of "ring nebulae" (planetary nebulae) in the Milky Way while working at the Harvard College Observatory in 1936.

NGC 5548

NGC 5548 is a Type I Seyfert galaxy with a bright, active nucleus. This activity is caused by matter flowing onto a 65 million solar mass (M☉) supermassive black hole at the core. Morphologically, this is an unbarred lenticular galaxy with tightly-wound spiral arms, while shell and tidal tail features suggest that it has undergone a cosmologically-recent merger or interaction event. NGC 5548 is approximately 245 million light years away and appears in the constellation Boötes. The apparent visual magnitude of NGC 5548 is approximately 13.3 in the V band.In 1943, this galaxy was one of twelve nebulae listed by American astronomer Carl Keenan Seyfert that showed broad emission lines in their nuclei. Members of this class of objects became known as Seyfert galaxies, and they were noted to have a higher than normal surface brightness in their nuclei. Observation of NGC 5548 during the 1960s with radio telescopes showed an enhanced level of radio emission. Spectrograms of the nucleus made in 1966 showed that the energized region was confined to a volume a few parsecs across, where temperature were around 14000 K and the plasma had a dispersion velocity of ±450 km/s.Among astronomers, the accepted explanation for the active nucleus in NGC 5548 is the accretion of matter onto a supermassive black hole (SMBH) at the core. This object is surrounded by an orbiting disk of accreted matter drawn in from the surroundings. As material is drawn into the outer parts of this disk, it becomes photoionized, producing broad emission lines in the optical and ultraviolet bands of the electromagnetic spectrum. A wind of ionized matter, organized in filamentary structures at distances of 1–14 light days from the center, is flowing outward in the direction perpendicular to the accretion disk plane.The mass of the central black hole can be estimated based on the properties of the emission lines in the core region. Combined measurements yield an estimated mass of 6.54+0.26−0.25×107 M☉. In other words, it is some 65 million times the mass of the Sun. This result is consistent with other methods of estimating the mass of the SMBH in the nucleus of NGC 5548. Matter is falling onto this black hole at the estimated rate of 0.03 M☉ per year, whereas mass is flowing outward from the core at or above the rate of 0.92 M☉ each year. The inner part of the accretion disk surrounding the SMBH forms a thick, hot corona spanning several light hours that is emitting X-rays. When this radiation reaches the optically thick part of the accretion disk at a radius of around 1–2 light days, the X-rays are converted into heat.

NGC 7469

NGC 7469 is an intermediate spiral galaxy in the constellation of Pegasus. NGC 7469 is located about 200 million light years away from Earth, which means, given its apparent dimensions, that NGC 7469 is approximately 90,000 light years across. It was discovered by William Herschel on November 12, 1784.NGC 7469 is a type I Seyfert galaxy, characterised by its bright nucleus. It is also a luminous infrared source with a powerful starburst embedded into its circumnuclear region. The coexistence of a circumnuclear starburst ring and an active galactic nucleus have turned NGC 7469 into a key target for studying their relation. NGC 7469 interacts with its smaller companion IC 5283, forming a pair collectively known in the Atlas of Peculiar Galaxies as Arp 298.

Scientific phenomena named after people

This is a list of scientific phenomena and concepts named after people (eponymous phenomena). For other lists of eponyms, see eponym.


Seyfert is a surname, and may refer to:

Carl Keenan Seyfert (1911–1960), United States astronomer

Gabriele Seyfert (born 1948), German athlete in figure skating

J. Michael Seyfert (born 1959), German Mexican documentary filmmaker, photographer

Johann Caspar Seyfert (1697–1767), German music composer

Johann Gottfried Seyfert (1731–1772), German music composer, son of Johann Caspar Seyfert

R. Tracy Seyfert (born 1941), United States political figure from Pennsylvania

Seyfert's Sextet

Seyfert's Sextet is a group of galaxies about 190 million light-years away in the constellation Serpens. The group appears to contain six members, but one of the galaxies is a background object and another "galaxy" is actually a separated part of one of the other galaxies. The gravitational interaction among these galaxies should continue for hundreds of millions of years. Ultimately, the galaxies will merge to form a single giant elliptical galaxy.

Seyfert (crater)

Seyfert is a prominent lunar impact crater that is located on the far side of the Moon. It was named after American astronomer Carl Keenan Seyfert. It lies behind the eastern limb of the Moon, to the east of the crater Espin. Just to the north of Seyfert is the crater Harriot and equally close to the south is Polzunov.

The outer rim of this crater is slightly elongated to the north, and the northeastern rim is overlain by the satellite crater Seyfert A. This overlapping impact crater has a central ridge on its interior floor. There is a low ridge near the midpoint of Seyfert, but it is less prominent. The inner wall of Seyfert is wider along the northern edge, west of Seyfert A.

Several small craters lie along the rim and interior of Seyfert, including a merged group of small craters along the eastern inner wall, a small crater intruding into the southeastern rim, and a pair of small craters along the southern rim of Seyfert A. The interior floor of Seyfert is relatively level, and is marked by a number of tiny craterlets. Traces of the ray system from Giordano Bruno to the northwest lie along the rim and interior floor of Seyfert.

Seyfert galaxy

Seyfert galaxies are one of the two largest groups of active galaxies, along with quasars. They have quasar-like nuclei (very luminous, distant and bright sources of electromagnetic radiation) with very high surface brightnesses whose spectra reveal strong, high-ionisation emission lines, but unlike quasars, their host galaxies are clearly detectable.Seyfert galaxies account for about 10% of all galaxies and are some of the most intensely studied objects in astronomy, as they are thought to be powered by the same phenomena that occur in quasars, although they are closer and less luminous than quasars. These galaxies have supermassive black holes at their centers which are surrounded by accretion discs of in-falling material. The accretion discs are believed to be the source of the observed ultraviolet radiation. Ultraviolet emission and absorption lines provide the best diagnostics for the composition of the surrounding material.Seen in visible light, most Seyfert galaxies look like normal spiral galaxies, but when studied under other wavelengths, it becomes clear that the luminosity of their cores is of comparable intensity to the luminosity of whole galaxies the size of the Milky Way.Seyfert galaxies are named after Carl Seyfert, who first described this class in 1943.

Timeline of United States discoveries

Timeline of United States discoveries encompasses the breakthroughs of human thought and knowledge of new scientific findings, phenomena, places, things, and what was previously unknown to exist. From a historical stand point, the timeline below of United States discoveries dates from the 18th century to the current 21st century, which have been achieved by discoverers who are either native-born or naturalized citizens of the United States.

With an emphasis of discoveries in the fields of astronomy, physics, chemistry, medicine, biology, geology, paleontology, and archaeology, United States citizens acclaimed in their professions have contributed much. For example, the "Bone Wars," beginning in 1877 and ending in 1892, was an intense period of rivalry between two American paleontologists, Edward Drinker Cope and Othniel Charles Marsh, who initiated several expeditions throughout North America in the pursuit of discovering, identifying, and finding new species of dinosaur fossils. In total, their large efforts resulted in when 142 species of dinosaurs being discovered. With the founding of the National Aeronautics and Space Administration (NASA) in 1958, a vision and continued commitment by the United States of finding extraterrestrial and astronomical discoveries has helped the world to better understand our solar system and universe. As one example, in 2008, the Phoenix lander discovered the presence of frozen water on the planet Mars of which scientists such as Peter H. Smith of the University of Arizona Lunar and Planetary Laboratory (LPL) had suspected before the mission confirmed its existence.

Timeline of knowledge about galaxies, clusters of galaxies, and large-scale structure

Timeline of galaxies, clusters of galaxies, and large-scale structure of the universe

Vanderbilt University

Vanderbilt University (informally Vandy) is a private research university in Nashville, Tennessee. Founded in 1873, it was named in honor of New York shipping and rail magnate Cornelius Vanderbilt, who provided the school its initial $1-million endowment despite having never been to the South. Vanderbilt hoped that his gift and the greater work of the university would help to heal the sectional wounds inflicted by the Civil War.Vanderbilt enrolls approximately 12,800 students from all 50 U.S. states and over 100 foreign countries in four undergraduate and six graduate and professional schools. The university is in the process of converting its residence halls into an academic residential college system. Several research centers and institutes are affiliated with the university, including the Robert Penn Warren Center for the Humanities, the Freedom Forum First Amendment Center, and Dyer Observatory. Vanderbilt University Medical Center, formerly part of the university, became a separate institution in 2016. With the exception of the off-campus observatory, all of the university's facilities are situated on its 330-acre (1.3 km2) campus in the heart of Nashville, 1.5 miles (2.4 km) from downtown. Despite its urban surroundings, the campus itself is a national arboretum and features over 300 different species of trees and shrubs.

The Fugitives and Southern Agrarians were based at the university in the first half of the 20th century and helped revive Southern literature among others. The Jean and Alexander Heard Library, the campus library system, contains over 8 million items across ten libraries and stands as one of the nation's top research libraries. Vanderbilt Television News Archive holds the most extensive collection of television news coverage in the world, with over 40,000 hours of content. BioVU, Vanderbilt's DNA databank, is one of the largest of its kind in the world, running over 200 ongoing projects and holding over 225,000 samples. Additionally, Vanderbilt's Institute for Space and Defense Electronics, the largest of its type in the world, provides integral support to several companies, agencies, and governmental units, including Boeing, NASA, and the United States Department of Defense.Vanderbilt has many distinguished alumni and affiliates, including 45 current and former members of the United States Congress, 17 U.S. Ambassadors, 13 governors, nine billionaires, seven Nobel Prize laureates, two Vice Presidents of the United States, and two U.S. Supreme Court Justices. Other notable alumni include Rhodes Scholars, Pulitzer Prize winners, Academy Award winners, Grammy Award winners, MacArthur Fellows, CEOs of Fortune 500 companies, heads of state and other leaders in foreign government, academics, musicians, professional athletes, and Olympians. Vanderbilt has more than 139,000 alumni, with 40 alumni clubs established worldwide.Vanderbilt is a founding member of the Southeastern Conference and has been the conference's only private school for a half-century.

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