NGC 1275

NGC 1275 (also known as Perseus A or Caldwell 24) is a type 1.5 Seyfert galaxy[3] located around 237 million light-years away[2] in the direction of the constellation Perseus. NGC 1275 corresponds to the radio galaxy Perseus A and is situated near the center of the large Perseus Cluster of galaxies.

NGC 1275
NGC 1275 Hubble
Hubble Space Telescope image of NGC 1275
Observation data (J2000 epoch)
Right ascension 03h 19m 48.1s[1]
Declination+41° 30′ 42″[1]
Redshift5264 ± 11 km/s[1]
Distance222 million light-years
68.2 Mpc[2]
Group or clusterPerseus Cluster
Apparent magnitude (V)12.6[1]
Apparent size (V)2′.2 × 1′.7[1]
Other designations
Perseus A,[1] PGC 12429,[1] UGC 2669,[1] QSO B0316+413, Caldwell 24, 3C 84[1]


Hubble Space Telescope image of the center of NGC 1275

NGC 1275 consists of two galaxies, a central type-cD galaxy in the Perseus Cluster, and a so-called "high velocity system" (HVS) which lies in front of it. The HVS is moving at 3000 km/s[4] towards the dominant system, and is believed to be merging with the Perseus Cluster. The HVS is not affecting the cD galaxy as it lies at least 200 thousand light years from it.[5] however tidal interactions are disrupting it and ram-pressure stripping produced by its interaction with the intracluster medium of Perseus is stripping its gas as well as producing large amounts of star formation within it[6]

The central cluster galaxy contains a massive network of spectral line emitting filaments,[7] which apparently are being dragged out by rising bubbles of relativistic plasma generated by the central active galactic nucleus.[8] Long gaseous filaments made up of threads of gas stretch out beyond the galaxy, into the multimillion-degree, X-ray–emitting gas that fills the cluster. The amount of gas contained in a typical thread is approximately one million times the mass of the Sun. They are only 200 light-years wide, are often very straight, and extend for up to 20,000 light-years.[9]

The existence of the filaments poses a problem. As they are much cooler than the surrounding intergalactic cloud, it is unclear how they have existed for such a long time, or why they have not warmed, dissipated or collapsed to form stars.[10][11] One possibility is that weak magnetic fields (about one-ten-thousandth the strength of Earth's field) exert enough force on the ions within the threads to keep them together.[10][11]

NGC 1275 contains 13 billion solar masses of molecular hydrogen that seems to be infalling from Perseus' intracluster medium in a cooling flow, both feeding its active nucleus[12] and fueling significant amounts of star formation[13]

The presence of an active nucleus demonstrates that a supermassive black hole is present in NGC 1275's center. The black hole is surrounded by a rotating disk of molecular gas.[14] High-resolution observations of the rotation of this disk obtained using adaptive optics at the Gemini North telescope indicate a central mass of approximately 800 million Solar masses, including both the mass of the black hole and of the inner core of the gas disk.[15]


NGC 1275 multi-wavelength composite

NGC 1275 multi-wavelength composite

NGC 1275 Hubble WikiSky

Hubble Space Telescope 1.73′ view of NGC 1275

Dazzling Galaxy

Wide multi-wavelength composite view of NGC 1275 and the center of the Perseus Cluster (VLA-Radio, Chandra-X-ray, Hubble-Visible, SDSS-Infrared)


  1. ^ a b c d e f g h i j k "NASA/IPAC Extragalactic Database". Results for NGC 1275. Retrieved 2006-11-19.
  2. ^ a b "Distance Results for NGC 1275". NASA/IPAC Extragalactic Database. Retrieved 2010-03-31.
  3. ^ Ho, Luis C.; Filippenko, Alex V.; Sargent, Wallace L. W. (October 1997). "A Search for "Dwarf" Seyfert Nuclei. III. Spectroscopic Parameters and Properties of the Host Galaxies". Astrophysical Journal Supplement. 112 (2): 315–390. arXiv:astro-ph/9704107. Bibcode:1997ApJS..112..315H. doi:10.1086/313041.
  4. ^ Minkowski R., 1957, in IAU Symp 4, Radio astronomy, p107
  5. ^ Gillmon K., Sanders J.S., Fabian A.C., An X-ray absorption analysis of the high-velocity system in NGC 1275, 2004, MNRAS, 348, 159
  6. ^ Gallagher, John S., III; Lee, M.; Canning, R.; Fabian, A.; O'Connell, R. W.; Sanders, J.; Zweibel, E. (2010). "Dusty Gas and New Stars: Disruption of the High Velocity Intruder Galaxy Falling Towards NGC 1275". Bulletin of the American Astronomical Society. 42: 552. Bibcode:2010AAS...21536308G.
  7. ^ Lynds R., Improved Photographs of the NGC1275 Phenomenon, 1970, ApJ, 159, L151
  8. ^ Hatch N.A., Crawford C.S., Johnstone R.M., Fabian A.C.: On the origin and excitation of the extended nebula surrounding NGC1275, 2006, MNRAS, 367, 433
  9. ^ Hubble Sees Magnetic Monster in Erupting Galaxy Newswise, Retrieved on August 21, 2008.
  10. ^ a b A. C. Fabian; et al. (2008-08-21). "Magnetic support of the optical emission line filaments in NGC 1275". Nature. 454 (7207): 968–970. arXiv:0808.2712. Bibcode:2008Natur.454..968F. doi:10.1038/nature07169. PMID 18719583.
  11. ^ a b Chang, Kenneth (2008-08-21). "Hubble Images Solve Galactic Filament Mystery". The New York Times.
  12. ^ Lim, Jeremy; Ao, Yi Ping; Dinh‐v‐Trung, Dinh-V-Trung (2008). "Radially Inflowing Molecular Gas in NGC 1275 Deposited by an X-Ray Cooling Flow in the Perseus Cluster". The Astrophysical Journal. 672 (1): 252–265. arXiv:0712.2979. Bibcode:2008ApJ...672..252L. doi:10.1086/523664.
  13. ^ O'Connell, Robert (2007). "Star Formation in the Perseus Cluster Cooling Flow". HST Proposal ID #11207. Cycle 16: 11207. Bibcode:2007hst..prop11207O.
  14. ^ Wilman, R. J.; Edge, A. C.; Johnstone, R. M. (2005). "The nature of the molecular gas system in the core of NGC 1275". Monthly Notices of the Royal Astronomical Society. 359 (2): 755–764. arXiv:astro-ph/0502537. Bibcode:2005MNRAS.359..755W. doi:10.1111/j.1365-2966.2005.08956.x.
  15. ^ Scharwächter, J.; McGregor, P. J.; Dopita, M. A.; Beck, T. L. (2013). "Kinematics and excitation of the molecular hydrogen accretion disc in NGC 1275". Monthly Notices of the Royal Astronomical Society. 429 (3): 2315. arXiv:1211.6750. Bibcode:2013MNRAS.429.2315S. doi:10.1093/mnras/sts502.

External links

Coordinates: Sky map 03h 19m 48.1s, +41° 30′ 42″


C24 or C.24 may refer to :

HMS C24, a 1908 British C class submarine

HMS Sheffield (C24) one of the Southampton sub class of the Town class cruisers of the Royal Navy during the Second World War

Sauber C24, a 2005 Formula One car

IVL C.24, a 1924 aircraft, the first to be designed in Finland

Caldwell 24 (NGC 1275, Perseus A), a galaxy in the constellation Perseus

Classical 24, a syndicated classical music radio network

C24 Ltd, a Worldwide hosting and application delivery specialists.and also :

Lignoceric acid, a fatty acid with a C24 backbone

Malignant neoplasm of other and unspecified parts of biliary tract ICD-10 code

a military designation of Douglas DC-8 aircraft

the U.N. Special Committee of the 24 on Decolonization

Caldwell catalogue

The Caldwell catalogue is an astronomical catalogue of 109 star clusters, nebulae, and galaxies for observation by amateur astronomers. The list was compiled by Patrick Moore as a complement to the Messier catalogue.While the Messier catalogue is used by amateur astronomers as a list of deep-sky objects for observation, Moore noted that Messier's list was not compiled for that purpose and excluded many of the sky's brightest deep-sky objects, such as the Hyades, the Double Cluster (NGC 869 and NGC 884), and the Sculptor Galaxy (NGC 253). The Messier catalogue was actually compiled as a list of known objects that might be confused with comets. Moore also observed that since Messier compiled his list from observations in Paris, it did not include bright deep-sky objects visible in the Southern Hemisphere, such as Omega Centauri, Centaurus A, the Jewel Box, and 47 Tucanae. Moore compiled a list of 109 objects to match the commonly accepted number of Messier objects (he excluded M110), and the list was published in Sky & Telescope in December 1995.Moore used his other surname – Caldwell – to name the list, since the initial of "Moore" is already used for the Messier catalogue. Entries in the catalogue are designated with a "C" and the catalogue number (1 to 109).

Unlike objects in the Messier catalogue, which are listed roughly in the order of discovery by Messier and his colleagues, the Caldwell catalogue is ordered by declination, with C1 being the most northerly and C109 being the most southerly, although two objects (NGC 4244 and the Hyades) are listed out of sequence. Other errors in the original list have since been corrected: it incorrectly identified the S Norma Cluster (NGC 6087) as NGC 6067 and incorrectly labelled the Lambda Centauri Cluster (IC 2944) as the Gamma Centauri Cluster.

Dark matter

Dark matter is a hypothetical form of matter that is thought to account for approximately 85% of the matter in the universe and about a quarter of its total energy density. The majority of dark matter is thought to be non-baryonic in nature, possibly being composed of some as-yet undiscovered subatomic particles. Its presence is implied in a variety of astrophysical observations, including gravitational effects that cannot be explained by accepted theories of gravity unless more matter is present than can be seen. For this reason, most experts think dark matter to be ubiquitous in the universe and to have had a strong influence on its structure and evolution. Dark matter is called dark because it does not appear to interact with observable electromagnetic radiation, such as light, and is thus invisible to the entire electromagnetic spectrum, making it extremely difficult to detect using usual astronomical equipment.The primary evidence for dark matter is that calculations show that many galaxies would fly apart instead of rotating, or would not have formed or move as they do, if they did not contain a large amount of unseen matter. Other lines of evidence include observations in gravitational lensing, from the cosmic microwave background, from astronomical observations of the observable universe's current structure, from the formation and evolution of galaxies, from mass location during galactic collisions, and from the motion of galaxies within galaxy clusters. In the standard Lambda-CDM model of cosmology, the total mass–energy of the universe contains 5% ordinary matter and energy, 27% dark matter and 68% of an unknown form of energy known as dark energy. Thus, dark matter constitutes 85% of total mass, while dark energy plus dark matter constitute 95% of total mass–energy content.Because dark matter has not yet been observed directly, if it exists, it must barely interact with ordinary baryonic matter and radiation, except through gravity. The primary candidate for dark matter is some new kind of elementary particle that has not yet been discovered, in particular, weakly-interacting massive particles (WIMPs), or gravitationally-interacting massive particles (GIMPs). Many experiments to directly detect and study dark matter particles are being actively undertaken, but none have yet succeeded. Dark matter is classified as cold, warm, or hot according to its velocity (more precisely, its free streaming length). Current models favor a cold dark matter scenario, in which structures emerge by gradual accumulation of particles.

Although the existence of dark matter is generally accepted by the scientific community, some astrophysicists, intrigued by certain observations that do not fit the dark matter theory, argue for various modifications of the standard laws of general relativity, such as modified Newtonian dynamics, tensor–vector–scalar gravity, or entropic gravity. These models attempt to account for all observations without invoking supplemental non-baryonic matter.

Jan Oort

Jan Hendrik Oort ( or ; 28 April 1900 – 5 November 1992) was a Dutch astronomer who made significant contributions to the understanding of the Milky Way and who was a pioneer in the field of radio astronomy. His New York Times obituary called him "one of the century's foremost explorers of the universe"; the European Space Agency website describes him as "one of the greatest astronomers of the 20th century" and states that he "revolutionised astronomy through his ground-breaking discoveries." In 1955, Oort's name appeared in Life magazine's list of the 100 most famous living people. He has been described as "putting the Netherlands in the forefront of postwar astronomy."Oort determined that the Milky Way rotates and overturned the idea that the Sun was at its center. He also postulated the existence of the mysterious invisible dark matter in 1932, which is believed to make up roughly 84.5% of the total matter in the Universe and whose gravitational pull causes "the clustering of stars into galaxies and galaxies into connecting strings of galaxies". He discovered the galactic halo, a group of stars orbiting the Milky Way but outside the main disk. Additionally Oort is responsible for a number of important insights about comets, including the realization that their orbits "implied there was a lot more solar system than the region occupied by the planets."The Oort cloud, the Oort constants, and the Asteroid, 1691 Oort, were all named after Jan Oort.

List of most massive black holes

This is an ordered list of the most massive black holes so far discovered (and probable candidates), measured in units of solar masses (M☉), or the mass of the Sun (approx. 2×1030 kilograms).

Multiwavelength Atlas of Galaxies

The Multiwavelength Atlas of Galaxies is a textbook and atlas of 35 well studied galaxies (including our Galaxy) authored by Glen Mackie of the Centre for Astrophysics & Supercomputing, Swinburne University of Technology. It was originally published in 2011 by Cambridge University Press.

NGC 1222

NGC 1222 is an early-type lenticular galaxy located in the constellation of Eridanus. The galaxy was discovered on 5 December 1883 by the French astronomer Édouard Stephan. John Louis Emil Dreyer, the compiler of the New General Catalogue, described it as a "pretty faint, small, round nebula" and noted the presence of a "very faint star" superposed on the galaxy.NGC 1222's morphological type of S0− would suggest that it should have a mostly smooth profile and a very dull appearance. However, the galaxy was imaged by the Hubble Space Telescope in 2016, and the image showed that there were several bright blue star forming regions, as well as dark reddish areas of interstellar dust. NGC 1222 is currently interacting with and swallowing two dwarf galaxies that are supplying the gas and dust needed to become a starburst galaxy.

NGC 1272

NGC 1272 is a massive elliptical galaxy located about 230 million light-years away in the constellation Perseus. It was discovered by astronomer Heinrich d'Arrest on February 14, 1863. NGC 1272 has an active nucleus and is the second brightest member of the Perseus Cluster after NGC 1275.

NGC 1278

NGC 1278 is an elliptical galaxy located about 230 million light-years away in the constellation Perseus. NGC 1278 was discovered by astronomer Heinrich d'Arrest on February 14, 1863. It was then rediscovered by astronomer Guillaume Bigourdan on October 22, 1884 and was later listed as IC 1907. NGC 1278 is a member of the Perseus Cluster and is a low-luminosity AGN (LLAGN).

NGC 4151

NGC 4151 is an intermediate spiral seyfert galaxy with weak inner ring structure located 19 megaparsecs (62 million light-years) from Earth in the constellation Canes Venatici. The galaxy was first mentioned by William Herschel on March 17, 1787; it was one of the two Seyfert galaxies described in the paper which defined the term. It is one of the nearest galaxies to Earth to contain an actively growing supermassive black hole; it was speculated that the nucleus may host a binary black hole, with about 40 million and about 10 million solar masses respectively, orbiting with a 15.8-year period. This is, however, still a matter of active debate.

Some astronomers nickname it the "Eye of Sauron" from its appearance.

NGC 708

NGC 708 is an elliptical galaxy located 240 million light-years away in the constellation Andromeda and was discovered by astronomer William Herschel on September 21, 1786. It is classified as a cD galaxy and is the brightest member of Abell 262. NGC 708 is a weak FR I radio galaxy and is also classfied as a type 2 seyfert galaxy.NGC 708 is surrounded by 4700 globular clusters.

Perseus (constellation)

Perseus is a constellation in the northern sky, being named after the Greek mythological hero Perseus. It is one of the 48 ancient constellations listed by the 2nd-century astronomer Ptolemy, and among the 88 modern constellations defined by the International Astronomical Union (IAU). It is located near several other constellations named after ancient Greek legends surrounding Perseus, including Andromeda to the west and Cassiopeia to the north. Perseus is also bordered by Aries and Taurus to the south, Auriga to the east, Camelopardalis to the north, and Triangulum to the west. Some star atlases during the early 19th century also depicted Perseus holding the disembodied head of Medusa, whose asterism was named together as Perseus et Caput Medusae; however, this never came into popular usage.

The galactic plane of the Milky Way passes through Perseus, whose brightest star is the yellow-white supergiant Alpha Persei (also called Mirfak), which shines at magnitude 1.79. It and many of the surrounding stars are members of an open cluster known as the Alpha Persei Cluster. The best-known star, however, is Algol (Beta Persei), linked with ominous legends because of its variability, which is noticeable to the naked eye. Rather than being an intrinsically variable star, it is an eclipsing binary. Other notable star systems in Perseus include X Persei, a binary system containing a neutron star, and GK Persei, a nova that peaked at magnitude 0.2 in 1901. The Double Cluster, comprising two open clusters quite near each other in the sky, was known to the ancient Chinese. The constellation gives its name to the Perseus cluster (Abell 426), a massive galaxy cluster located 250 million light-years from Earth. It hosts the radiant of the annual Perseids meteor shower—one of the most prominent meteor showers in the sky.

Perseus Cluster

The Perseus cluster (Abell 426) is a cluster of galaxies in the constellation Perseus. It has a recession speed of 5,366 km/s and a diameter of 863′. It is one of the most massive objects in the known universe, containing thousands of galaxies immersed in a vast cloud of multimillion-degree gas.

Phoenix Cluster

The Phoenix Cluster (SPT-CL J2344-4243) is a massive, type I galaxy cluster located at its namesake constellation, the southern constellation of Phoenix. It was initially detected in 2010 using the Sunyaev–Zel'dovich effect by the South Pole Telescope collaboration.It is one of the most massive galaxy clusters known, with the mass on the order of 2×1015 M☉. Most of the mass of the Phoenix Cluster is in the form of dark matter and its intracluster medium. The vast stellar halo of the Phoenix Cluster central galaxy extends to over 1.1 million light years from the center, making it one of the largest galaxies known. It is 22 times the diameter of our galaxy, and its starburst activity suggests that the galaxy is still growing larger.

The Phoenix Cluster is also producing more X-rays than any other known massive cluster.

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.

See also

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