Messier 77 or M77, also known as NGC 1068, is a barred spiral galaxy about 47 million light-years away in the constellation Cetus. Messier 77 was discovered by Pierre Méchain in 1780, who originally described it as a nebula. Méchain then communicated his discovery to Charles Messier, who subsequently listed the object in his catalog. Both Messier and William Herschel described this galaxy as a star cluster. Today, however, the object is known to be a galaxy.
The morphological classification of NGC 1068 in the De Vaucouleurs system is (R)SA(rs)b, where the '(R)' indicates an outer ring-like structure, 'SA' denotes a non-barred spiral, '(rs)' means a transitional inner ring/spiral structure, and 'b' says the spiral arms are moderately wound. Ann et al. (2015) gave it a class of SAa, suggesting a non-barred spiral galaxy with tightly wound arms. However, infrared images of the inner part of the galaxy reveal a prominent bar feature not seen in visual light, and for this reason it is now considered a barred spiral.
Messier 77 is an active galaxy with an Active Galactic Nucleus (AGN), which is obscured from view by astronomical dust at visible wavelengths. The diameter of the molecular disk and hot plasma associated with the obscuring material was first measured at radio wavelengths by the VLBA and VLA. The hot dust around the nucleus was subsequently measured in the mid-infrared by the MIDI instrument at the VLTI. It is the brightest and one of the closest and best-studied type 2 Seyfert galaxies, forming a prototype of this class.
X-ray source 1H 0244+001 in Cetus has been identified as Messier 77. Only one supernova has been detected in Messier 77. The supernova, named SN 2018 ivc, was discovered on 24 November 2018 by the DLT40 Survey. It is a type II supernova, and at discovery it was 15th magnitude and brightening.
Hubble Space Telescope image of M77 core
|Observation data (J2000 epoch)|
|Right ascension||02h 42m 40.771s|
|Declination||−00° 00′ 47.84″|
|Distance||47 Mly (14.4 Mpc)|
|Apparent magnitude (V)||9.6|
|Apparent size (V)||7′.1 × 6′.0|
|Notable features||One of the biggest galaxies|
of Messier's catalog.
Inclination estimated to be 40°.
|Cetus A, Arp 37, M77, NGC 1068, PGC 10266, UGC 2188|
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.Cetus
Cetus () is a constellation. Its name refers to Cetus, a sea monster in Greek mythology, although it is often called 'the whale' today. Cetus is located in the region of the sky that contains other water-related constellations such as Aquarius, Pisces, and Eridanus.Iota Ceti
Iota Ceti (ι Cet, ι Ceti) is the Bayer designation for a star system in the equatorial constellation of Cetus. It has the traditional name Deneb Kaitos Shemali. The name was from the Arabic word ذنب قيطس الشمالي - dhanab qayṭas al-shamālī, meaning the northern tail of the sea monster. it is visible to the naked eye with an apparent visual magnitude of 3.562. Based upon an annual parallax shift of 11.88 mas, it lies around 275 light years from the Sun.
In Chinese, 天倉 (Tiān Cāng), meaning Square Celestial Granary, refers to an asterism consisting of ι Ceti, η Ceti, θ Ceti, ζ Ceti, τ Ceti and 57 Ceti. Consequently, ι Ceti itself is known as 天倉一 (Tiān Cāng yī, English: the First Star of Square Celestial Granary.)This is an MK-standard star with a stellar classification of K1.5 III, indicating that it is an evolved K-type giant star. However, Houk and Swift (1999) list a classification of K1 II, which would indicate this is a bright giant. It is a suspected variable with a visual amplitude of around 0.05 magnitude. The star has about 2.8 times the mass of the Sun, 34 times the Sun's radius, and radiates 398 times the solar luminosity from its outer atmosphere at an effective temperature of 4,446 K.Iota Ceti forms a wide astrometric pair with a common proper motion companion, a magnitude 10.40 star at an angular separation of 106.4 arcseconds along a position angle of 191° (as of 2014). This companion may be a K-type star.Kappa2 Ceti
Kappa2 Ceti (κ2 Ceti), is a solitary, yellow-hued star located in the equatorial constellation of Cetus. It is faintly visible to the naked eye with an apparent visual magnitude of 5.66. Based upon an annual parallax shift of 10.11 mas as seen from Earth, it is located about 320 light years from the Sun.
This is an evolved G-type giant star with a stellar classification of G8 III. It is a red clump star on the horizontal branch, which indicates it is generating energy through helium fusion at its core. The star has 2.46 times the mass of the Sun and has expanded to 8.2 times the Sun's radius. It is radiating 42 times the solar luminosity from its photosphere at an effective temperature of 5,007 K.List of black holes
This is a list of black holes (and stars considered probable candidates) organized by size (including black holes of undetermined mass); some items in this list are galaxies or star clusters that are believed to be organized around a black hole. Messier and New General Catalogue designations are given where possible.M77
M77 or M-77 may refer to:
M-77 (Michigan highway), a state highway in Michigan
M77 motorway, a motorway in Scotland
M-77 pistol, a semi-automatic pistol
Miles M.77 Sparrowjet, a 1950 twin-engined jet-powered racing aeroplane
Zastava M77, a Serbian assault rifle
Ruger M77, a bolt-action rifle
Messier 77, a spiral galaxy in the constellation Cetus
M-77 Oganj, a Serbian multiple rocket launcherMessier object
The Messier objects are a set of 110 astronomical objects cataloged by the French astronomer Charles Messier in his Catalogue des Nébuleuses et des Amas d'Étoiles ("Catalogue of Nebulae and Star Clusters").
Because Messier was interested in finding only comets, he created a list of non-comet objects that frustrated his hunt for them. The compilation of this list, in collaboration with his assistant Pierre Méchain, is known as the Messier catalogue. This catalogue of objects is one of the most famous lists of astronomical objects, and many Messier objects are still referenced by their Messier number.
The catalogue includes some astronomical objects that can be observed from Earth's Northern Hemisphere such as deep-sky objects, a characteristic which makes the Messier objects extremely popular targets for amateur astronomers.A preliminary version first appeared in the Memoirs of the French Academy of Sciences in 1771,
and the last item was added in 1966 by Kenneth Glyn Jones, based on Messier's observations.
The first version of Messier's catalogue contained 45 objects and was published in 1774 in the journal of the French Academy of Sciences in Paris. In addition to his own discoveries, this version included objects previously observed by other astronomers, with only 17 of the 45 objects being Messier's.
By 1780 the catalogue had increased to 80 objects. The final version of the catalogue containing 103 objects was published in 1781 in the Connaissance des Temps for the year 1784.
However, due to what was thought for a long time to be the incorrect addition of Messier 102, the total number remained 102. Other astronomers, using side notes in Messier's texts, eventually filled out the list up to 110 objects.The catalogue consists of a diverse range of astronomical objects, ranging from star clusters and nebulae to galaxies. For example, Messier 1 is a supernova remnant, known as the Crab Nebula, and the great spiral Andromeda Galaxy is M31. Many further inclusions followed in the next century when the first addition came from Nicolas Camille Flammarion in 1921, who added Messier 104 after finding Messier's side note in his 1781 edition exemplar of the catalogue. M105 to M107 were added by Helen Sawyer Hogg in 1947, M108 and M109 by Owen Gingerich in 1960, and M110 by Kenneth Glyn Jones in 1967.NGC 1084
NGC 1084 is an unbarred spiral galaxy in constellation Eridanus. It is at a distance of about 65 million light-years away from Earth. It was discovered by William Herschel on 10 January 1785. The galaxy has multiple spiral arms, which are not well defined. It belongs in the same group with NGC 988, NGC 991, NGC 1022, NGC 1035, NGC 1042, NGC 1047, NGC 1052 and NGC 1110. The group is associated with Messier 77 group.NGC 1084 has been home of 5 supernovae in the last 50 years, 1963P (mag. 14), 1996an (type II, mag. 14), 1998dl (type II, mag. 16), 2009H (type II, mag. 17), and 2012ec (type IIP, mag. 14,5). Star formation in the galaxy is chaotic and not confined at the spiral arms of the galaxy, however, not as high as to classify the galaxy as a starburst galaxy. Star formation has taken place in small bursts in the last 40 million years. The reason of this activity has been proposed to be a merger with a gas-rich dwarf galaxy. A radio source has been detacted 3,5' south-west of the galaxy, connected to it by a bridge.NGC 3810
NGC 3810 is a spiral galaxy located in the constellation Leo. It is located at a distance of circa 50 million light years from Earth, which, given its apparent dimensions, means that NGC 3810 is about 60,000 light years across. It was discovered by William Herschel οn March 15, 1784.The bright galaxy NGC 3810 demonstrates spiral structure similar to that of Messier 77. The central part of the galaxy disk is of high surface brightness and features tightly wound spirals. Outside this disk lie more open arms with lower surface brightness. The bright central region is thought to be forming many new stars and is outshining the outer areas of the galaxy by some margin. Further out the galaxy displays strikingly rich dust clouds along its spiral arms. Hot young blue stars show up in giant clusters far from the centre and the arms are also littered with bright red giant stars. Two supernovae have been observed in NGC 3810, SN 1997dq (type Ib, mag: 15), and SN 2000ew (type Ic, mag: 14.9).NGC 3810 forms a small group of galaxies with NGC 3773, the NGC 3810 group, which is part of the Virgo Supercluster.NGC 936
NGC 936 is a barred lenticular galaxy in the constellation Cetus. It is at a distance of about 60 million light-years away from Earth. Its nucleus and prominent bar have high surface brightness. Because of the shape of the prominent bar, the nucleus and the ring of stars at the end of the barrel, the galaxy has been compared with the shape of a TIE fighter, from the Star Wars universe, and thus NGC 936 has been named Darth Vader’s Galaxy or Darth Vader’s Starfighter. By measuring the radial velocity of the disc, Kormendy found in 1986 that the disc is stable, which is the reason why it is so smooth.It was discovered by William Herschel on 6 January 1785, who classified it as a planetary nebula, because of its round shape. One supernova (SN 2003gs) has been observed in NGC 936 and was typed as a peculiar Type Ia supernova, characterized by its fast evolution. SN 2003gs peaked at magnitude 14.NGC 936 forms a pair with the spiral galaxy NGC 941, at 12.6' separation, however, the two galaxies do not interact. This galaxy group (the NGC 936 group) also includes the galaxies NGC 955, UGC 01945 and IC 225. The group is associated with Messier 77 group.NGC 988
NGC 988 is a spiral galaxy located in the constellation Cetus. It lies at a distance of 50 million light years from Earth, which, given its apparent dimensions, means that NGC 988 is about 75,000 light years across. Magnitude 7.1 HD 16152 is superposed 52" northwest of the center of NGC 988. The galaxy was discovered by Édouard Jean-Marie Stephan in 1879. One ultraluminous X-ray source has been detected in NGC 988.NGC 988 is the brightest galaxy in NGC 1052 group (which is also known as NGC 988 group),which also includes the elliptical galaxy NGC 1052, NGC 991, NGC 1022, NGC 1035, NGC 1042, NGC 1047, NGC 1051, NGC 1084, NGC 1110. It belongs in the same galaxy cloud as Messier 77.One supernova has been discovered in NGC 988, SN 2017gmr, a Type II supernova discovered on 4 September 2017.Phi1 Ceti
Phi1 Ceti is a star located in the equatorial constellation Cetus. It is visible to the naked eye with an apparent visual magnitude of +4.78. Based upon an annual parallax shift of 13.96 mas, it is located about 234 light years from the Sun.
At an age of about 2.21 billion years, this is an evolved red clump giant star with a stellar classification of K0 III. It is presently on the horizontal branch and is generating energy through the nuclear fusion of helium at its core. The star is suspected of variability; it has been measured to vary between magnitudes 4.75 and 4.78.Based upon the motion of this star through space, Phi1 Ceti is a probable member of the proposed Wolf 630 moving group. This is a set of stars centered on Wolf 630 that are moving nearly in parallel and have an age of around 2.7±0.5 billion years. They may be former members of a dissolved open cluster.Phi3 Ceti
Phi3 Ceti is a solitary, orange-hued star in the equatorial constellation of Cetus. It is faintly visible to the naked eye with an apparent visual magnitude of 5.31. Based upon an annual parallax shift of 5.92 mas as seen from Earth, it is located roughly 550 light years from the Sun, give or take 30 light years.
This is an evolved K-type giant star with a stellar classification of K5 III. The measured angular diameter of Phi3 Ceti is 2.42±0.13 mas. At the estimated distance of the star, this yields a physical size of about 44 times the Sun's radius. It has about 1.4 times the mass of the Sun and radiates 429 times the solar luminosity from its photosphere at an effective temperature of 3,940 K.Phi4 Ceti
Phi4 Ceti is a solitary, orange-hued star in the equatorial constellation Cetus. It is faintly visible to the naked eye with an apparent visual magnitude of 5.61. Based upon an annual parallax shift of 10.20 mas as seen from Earth, it is located roughly 320 light years from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.10 due to interstellar dust.This is an evolved G-type giant star with a stellar classification of G8 III. It is a red clump star on the horizontal branch, which indicates it is generating energy through helium fusion at its core. The star has about 1.76 times the mass of the Sun and has expanded to ten times the Sun's radius. It is radiating 60 times the solar luminosity from its photosphere at an effective temperature of 4,903 K.Pi Ceti
Pi Ceti, Latinized from π Ceti, is the Bayer designation for a star system in the equatorial constellation of Cetus. It is visible to the naked eye with an apparent visual magnitude of 4.238. Based upon an annual parallax shift of 8.30 mas, it is located around 393 light years from the Sun.
This is a single-lined spectroscopic binary system with a nearly circular orbit and a period of 7.45 years. The fact that the system has a negligible eccentricity is surprising for such a long period, and may suggest that the secondary is a white dwarf that had its orbit circularized during a mass-transfer event.The primary, component A, is a normal B-type star that has been given stellar classifications of B7 V and B7 IV. It appears very young – less than half a million years in age – and may still be on a pre-main sequence track. The star shows no magnetic field but it does emit an infrared excess.Rho Ceti
Rho Ceti , Latinized from ρ Ceti, is the Bayer designation for a star in the equatorial constellation of Cetus. It is faintly visible to the naked eye with an apparent visual magnitude of 4.885. The distance to this star, based upon an annual parallax shift of 7.15 mas, is around 460 light years.
This is an A-type main sequence star with a stellar classification of A0 V. It is spinning rapidly with a projected rotational velocity of 219 km/s, giving the star an oblate shape with an equatorial bulge that is 10% larger than the polar radius. The star has an estimated size 3.1 times the radius of the Sun and is radiating 178 times the solar luminosity from its outer atmosphere at an effective temperature of 8,905 K.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.Sigma Ceti
Sigma Ceti (σ Ceti) is the Bayer designation for a star in the equatorial constellation of Cetus. With an apparent visual magnitude of 4.78, it can be seen with the naked eye on a dark night. Based upon an annual parallax shift of 37.46 mas, it lies at an estimated distance of 87.1 light years from the Sun. It is a probable astrometric binary star system.The primary, component A, appears to be a normal F-type main sequence star with a stellar classification of F5 V. However, Malaroda (1975) assigned it a classification of F4 IV, which would suggest it is a more evolved subgiant star. It is estimated to have 121% of the Sun's mass and around 150% of the radius of the Sun. With an age of about 2.1 billion years, it is radiating 7.6 times the solar luminosity from its outer atmosphere at an effective temperature of 6,527 K.Zeta Ceti
Zeta Ceti (ζ Ceti, abbreviated Zeta Cet, ζ Cet) is a binary star in the equatorial constellation of Cetus. It has a combined apparent visual magnitude of 3.74, which is bright enough to be seen with the naked eye. Based upon parallax measurements taken during the Hipparcos mission, it is approximately 235 light-years from the Sun.Zeta Ceti is the primary or 'A' component of a double star system designated WDS J01515-1020 (the secondary or 'B' component is HD 11366). Zeta Ceti's two components are therefore designated WDS J01515-1020 Aa and Ab. Aa is also named Baten Kaitos.
New General Catalogue 1000 to 1499
List of notable Seyfert galaxies