NGC 3982 | |
---|---|
Observation data (J2000 epoch) | |
Constellation | Ursa Major |
Right ascension | 11h 56m 28.1s [1] |
Declination | +55° 07′ 31″ [1] |
Redshift | 1109 ± 6 km/s [1] |
Distance | 67.8 ± 2.5 Mly (20.80 ± 0.77 Mpc) [2] 70.38 ± 0.23 Mly (21.58 ± 0.07 Mpc) [3] |
Group or cluster | M109 Group |
Apparent magnitude (V) | 12.0 [1] |
Characteristics | |
Type | SAB(r)b [1] |
Apparent size (V) | 1.7′ × 1.5′ [1] |
Other designations | |
UGC 6918, [1] PGC 37520 [1] |
NGC 3982(also known as UGC 6918) is an intermediate spiral galaxy approximately 68 million light-years away in the constellation Ursa Major. It was discovered by William Herschel on April 14, 1789, and misclassified as a planetary nebula. [4] NGC 3982 is a part of the M109 Group.
At an apparent magnitude of 12.0, NGC 3982 needs a telescope to be viewed. Using small telescopes, the galaxy appears as a very faint, diffuse patch of light, with its central region appearing as a slightly brighter diffuse ball.
NGC 3982 is a Seyfert 2 galaxy that spans about 30,000 light-years, about one-third of the size of our Milky Way galaxy. The galaxy is receding from us at about 1,109 km/s. The galaxy is a typical spiral galaxy, similar to our Milky Way. It harbors a supermassive black hole at its core and has massive regions of star formation in the bright blue knots in the spiral arms. [5] Supernovae are likely to be found within these regions.
NGC 3982 has a high rate of star birth within its arms, which are lined by pink star-forming regions of glowing hydrogen and newborn blue star clusters. Its bright nucleus is home to older populations of stars, which grow more densely packed toward the center. The galaxy also has active star formation in the circumnuclear region, estimated at 0.52 M☉/year. The HST image of NGC 3982 shows a mini-spiral between the circumnuclear star-forming region and the galaxy's nucleus, which could be the channel through which gas is transported to the supermassive black hole from the star-forming region.
NGC 3982 is a member of the M109 Group, a group of galaxies located in the constellation Ursa Major that may contain over 50 galaxies. The group was named after the brightest galaxy in the group, the spiral galaxy M109. [6] [7] [8]
Astronomers are interested in studying this galaxy as it can help in measuring extragalactic distances. It is helpful because it possesses two tools used to estimate astronomical distances: supernovae and Cepheid variable stars.
In 1998, the light from a supernova in NGC 3982 (later called SN 1998aq ) reached Earth and was discovered by British amateur astronomer Mark Armstrong. It was discovered when it had apparent magnitude 14.9, and had grown considerably brighter by two days after its initial sighting (it reached maximum magnitude 14.0).
The supernova explosion resulted from a binary system in which a white dwarf star was capturing mass from its companion star. When the white dwarf had gathered enough mass and was no longer able to support itself, the star detonated in a violent and extremely bright explosion.
Since a supernova occurs in a typical spiral galaxy (roughly) once every 100 years, astronomers have software continuously monitor high-resolution automatic survey camera images of galaxies like NGC 3982, for early detection of supernova explosions.
The Pinwheel Galaxy is a face-on, unbarred, and counterclockwise spiral galaxy located 21 million light-years from Earth in the constellation Ursa Major. It was discovered by Pierre Méchain in 1781 and was communicated that year to Charles Messier, who verified its position for inclusion in the Messier Catalogue as one of its final entries.
Messier 61 is an intermediate barred spiral galaxy in the Virgo Cluster of galaxies. It was first discovered by Barnaba Oriani on May 5, 1779, six days before Charles Messier discovered the same galaxy. Messier had observed it on the same night as Oriani but had mistaken it for a comet. Its distance has been estimated to be 45.61 million light years from the Milky Way Galaxy. It is a member of the M61 Group of galaxies, which is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster.
The cosmic distance ladder is the succession of methods by which astronomers determine the distances to celestial objects. A direct distance measurement of an astronomical object is possible only for those objects that are "close enough" to Earth. The techniques for determining distances to more distant objects are all based on various measured correlations between methods that work at close distances and methods that work at larger distances. Several methods rely on a standard candle, which is an astronomical object that has a known luminosity.
Centaurus A is a galaxy in the constellation of Centaurus. It was discovered in 1826 by Scottish astronomer James Dunlop from his home in Parramatta, in New South Wales, Australia. There is considerable debate in the literature regarding the galaxy's fundamental properties such as its Hubble type and distance. NGC 5128 is one of the closest radio galaxies to Earth, so its active galactic nucleus has been extensively studied by professional astronomers. The galaxy is also the fifth-brightest in the sky, making it an ideal amateur astronomy target. It is only visible from the southern hemisphere and low northern latitudes.
The Whirlpool Galaxy, also known as Messier 51a (M51a) or NGC 5194, is an interacting grand-design spiral galaxy with a Seyfert 2 active galactic nucleus. It lies in the constellation Canes Venatici, and was the first galaxy to be classified as a spiral galaxy. It is 7.22 megaparsecs away and 23.58 kiloparsecs (76,900 ly) in diameter.
Messier 81 (also known as NGC 3031 or Bode's Galaxy) is a grand design spiral galaxy about 12 million light-years away in the constellation Ursa Major. It has a D25 isophotal diameter of 29.44 kiloparsecs (96,000 light-years). Because of its relative proximity to the Milky Way galaxy, large size, and active galactic nucleus (which harbors a 70 million M☉ supermassive black hole), Messier 81 has been studied extensively by professional astronomers. The galaxy's large size and relatively high brightness also makes it a popular target for amateur astronomers. In late February 2022, astronomers reported that M81 may be the source of FRB 20200120E, a repeating fast radio burst.
Messier 108 is a barred spiral galaxy about 28 million light-years away from Earth in the northern constellation Ursa Major. It was discovered by Pierre Méchain in 1781 or 1782. From the Earth, this galaxy is seen almost edge-on.
NGC 3184, the Little Pinwheel Galaxy, is a spiral galaxy approximately 40 million light-years away in the constellation Ursa Major. Its name comes from its resemblance to the Pinwheel Galaxy. It has two HII regions named NGC 3180 and NGC 3181.
NGC 6946, sometimes referred to as the Fireworks Galaxy, is a face-on intermediate spiral galaxy with a small bright nucleus, whose location in the sky straddles the boundary between the northern constellations of Cepheus and Cygnus. Its distance from Earth is about 25.2 million light-years or 7.72 megaparsecs, similar to the distance of M101 in the constellation Ursa Major. Both were once considered to be part of the Local Group, but are now known to be among the dozen bright spiral galaxies near the Milky Way but beyond the confines of the Local Group. NGC 6946 lies within the Virgo Supercluster.
NGC 4725 is an intermediate barred spiral galaxy with a prominent ring structure, located in the northern constellation of Coma Berenices near the north galactic pole. It was discovered by German-born British astronomer William Herschel on April 6, 1785. The galaxy lies at a distance of approximately 40 megalight-years from the Milky Way. NGC 4725 is the brightest member of the Coma I Group of the Coma-Sculptor Cloud, although it is relatively isolated from the other members of this group. This galaxy is strongly disturbed and is interacting with neighboring spiral galaxy NGC 4747, with its spiral arms showing indications of warping. The pair have an angular separation of 24′, which corresponds to a projected linear separation of 370 kly. A tidal plume extends from NGC 4747 toward NGC 4725.
NGC 1309 is a spiral galaxy located approximately 120 million light-years away, appearing in the constellation Eridanus. It is about 75,000 light-years across, and is about 3/4s the width of the Milky Way. Its shape is classified as SA(s)bc, meaning that it has moderately wound spiral arms and no ring. Bright blue areas of star formation can be seen in the spiral arms, while the yellowish central nucleus contains older-population stars. NGC 1309 is one of over 200 members of the Eridanus Group of galaxies.
NGC 5253 is an irregular galaxy in the constellation Centaurus. It was discovered by William Herschel on 15 March 1787.
NGC 4261 is an elliptical galaxy located around 100 million light-years away in the constellation Virgo. It was discovered April 13, 1784, by the German-born astronomer William Herschel. The galaxy is a member of its own somewhat meager galaxy group known as the NGC 4261 group, which is part of the Virgo Cluster.
NGC 4639 is a barred spiral galaxy located in the equatorial constellation of Virgo. It was discovered by German-born astronomer William Herschel on April 12, 1784. John L. E. Dreyer described it as "pretty bright, small, extended, mottled but not resolved, 12th magnitude star 1 arcmin to southeast". This is a relatively nearby galaxy, lying approximately 72 million light-years away from the Milky Way. It is a companion to NGC 4654, and the two appear to have interacted roughly 500 million years ago. NGC 4639 is a member of the Virgo Cluster.
NGC 7424 is a barred spiral galaxy located 37.5 million light-years away in the southern constellation Grus. Its size makes it similar to our own galaxy, the Milky Way. It is called a "grand design" galaxy because of its well defined spiral arms. Two supernovae and two ultraluminous X-ray sources have been discovered in NGC 7424.
SN 1998aq is a nearby supernova located in the intermediate spiral galaxy NGC 3982, offset 18″ west and 7″ of the galactic nucleus. It was discovered April 13, 1998 by amateur astronomer Mark Armstrong and was confirmed by fellow British amateur Ron Arbour; both members of the U.K. Supernova/Nova Patrol. The event was not visible on a prior check by Armstrong made April 7. It reached peak brightness on April 27, and 15 days later had declined by 1.14 magnitudes in the B (blue) band.
NGC 3631 is a spiral galaxy located in the constellation Ursa Major. It is located at a distance of about 35 million light years from Earth, which, given its apparent dimensions, means that NGC 3631 is about 60,000 light years across. It was discovered by William Herschel on April 14, 1789. It is a grand design spiral galaxy seen face on.
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 6951 is a barred spiral galaxy located in the constellation Cepheus. It is located at a distance of about 75 million light-years from Earth, which, given its apparent dimensions, means that NGC 6951 is about 100,000 light-years across. It was discovered by Jérôme Eugène Coggia in 1877 and independently by Lewis Swift in 1878.
IC 4182 is a Magellanic spiral galaxy in the constellation Canes Venatici. The galaxy lies about 14 million light years away from Earth, which means, given its apparent dimensions, that IC 4182 is approximately 30,000 light years across. It was discovered by Max Wolf in 1904.