NGC 6240, also known as the Starfish Galaxy, is a nearby ultraluminous infrared galaxy (ULIRG) in the constellation Ophiuchus. The galaxy is the remnant of a merger between three smaller galaxies. The collision between the three progenitor galaxies has resulted in a single, larger galaxy with three distinct nuclei and a highly disturbed structure, including faint extensions and loops.
A megamaser is a type of astrophysical maser, which is a naturally occurring source of stimulated spectral line emission. Megamasers are distinguished from other astrophysical masers by their large isotropic luminosity. Megamasers have typical luminosities of 103 solar luminosities (L☉), which is 100 million times brighter than masers in the Milky Way, hence the prefix mega. Likewise, the term kilomaser is used to describe masers outside the Milky Way that have luminosities of order L☉, or thousands of times stronger than the average maser in the Milky Way, gigamaser is used to describe masers billions of times stronger than the average maser in the Milky Way, and extragalactic maser encompasses all masers found outside the Milky Way. Most known extragalactic masers are megamasers, and the majority of megamasers are hydroxyl (OH) megamasers, meaning the spectral line being amplified is one due to a transition in the hydroxyl molecule. There are known megamasers for three other molecules: water (H2O), formaldehyde (H2CO), and methine (CH).
Luminous infrared galaxies or LIRGs are galaxies with luminosities, the measurement of brightness, above 1011 L☉. They are also referred to as submillimeter galaxies (SMGs) through their normal method of detection. LIRGs are more abundant than starburst galaxies, Seyfert galaxies and quasi-stellar objects at comparable luminosity. Infrared galaxies emit more energy in the infrared than at all other wavelengths combined. A LIRG's luminosity is 100 billion times that of the Sun.
NGC 4194, the Medusa merger, is a galaxy merger in the constellation Ursa Major about 128 million light-years (39.1 Mpc) away. It was discovered on April 2, 1791 by German-British astronomer William Herschel. Due to its disturbed appearance, it is object 160 in Halton Arp's 1966 Atlas of Peculiar Galaxies.
FSC15307+3253 is an ultraluminous infrared galaxy (ULIRG), with a luminosity between 8 and 1000 μm of approximately 2×1013L⊙, possibly the highest currently known. The "FSC" refers to Faint Source Catalogue, one of the source catalogs produced by the IRAS infrared survey mission. The emission is believed due to some combination of starburst activity and accretion onto a super-massive black hole, producing primary radiation at shorter wavelengths which is mostly blocked by obscuring dust, which is in turn heated and re-radiates in the infrared. The redshift of the source is z = 0.93, indicating a distance of the order of 7 billion light years.
Markarian 1034 is a pair of spiral galaxies comprising PGC 9074 and PGC 9071, located in the constellation Triangulum. They are located at a distance of 465 million light-years from Earth and are classified as luminous infrared galaxies.
NGC 877 is an intermediate spiral galaxy located in the constellation Aries. It is located at a distance of circa 160 million light years from Earth, which, given its apparent dimensions, means that NGC 877 is about 115,000 light years across. It was discovered by William Herschel on October 14, 1784. It interacts with NGC 876.
NGC 5910 is an elliptical galaxy located about 540 million light-years away in the constellation Serpens. It was discovered by astronomer William Hershel on April 13, 1785. NGC 5910 is also a strong radio source with a conspicuous nuclear jet.
Markarian 273 is a galaxy merger located in the constellation Ursa Major. It is located at a distance of about 500 million light years from Earth, which, given its apparent dimensions, means that Markarian 273 is about 130,000 light years across. It is an ultraluminous infrared galaxy and a Seyfert galaxy.
UGC 5101 is a galaxy merger located in the constellation Ursa Major. It is located at a distance of about 530 million light years from Earth. It is an ultraluminous infrared galaxy. The total infrared luminosity of the galaxy is estimated to be 1011.95 L☉ and the galaxy has a total star formation rate of 105 M☉ per year.
MCG -03-04-014 or PGC 4167, is a spiral galaxy located 450 million light-years in the constellation of Cetus. MCG -03-04-014 is classified as a luminous infrared galaxy, meaning it has high star-formation regions. MCG -03-04-014 has a galactic center that is obscured by dust lanes and presents an abundant supply of molecular gas. The reasons behind the luminosity of this galaxy are debated among astronomers. Some attribute it to recent starbursts, while others point to activity in the galaxies' supermassive black holes. It is also considered that both factors may contribute. The exact cause remains uncertain.
SDSSCGB 10189 is a trio of interacting galaxies that is located in the constellation of Boötes. They are located 1.04 billion light-years away from the Solar System and are gravitationally interacting.
IRAS 05189-2524 is a galaxy merger located in the constellation Lepus. It is located 603 million light-years away from the Solar System and has an approximate diameter of 75,000 light-years.
IRAS F11119+3257 or simply as F11119+3257, is a galaxy located in constellation Ursa Major. With a redshift of 0.187580, it has a light travel time distance of 2.5 billion light-years and is considered an ultraluminous infrared galaxy (ULIRG).
IRAS 09104+4109 is a galaxy located in the constellation Lynx. With a redshift of 0.440797, the light travel time for this galaxy, corresponds to 4.8 billion light-years from Earth. It is the brightest cluster galaxy in CDGS 25, also known as WHL J091345.5+405628 and a notable, unique ultraluminous infrared galaxy.
IRAS 13218+0552 known as SFRS 263, is a galaxy merger located in the Virgo constellation. Its redshift is 0.202806, putting the object at 2.6 billion light-years away from Earth. It is a Seyfert galaxy and a luminous infrared galaxy.
PKS 1345+125 known as PKS 1345+12 and 4C +12.50, is an ultraluminous infrared galaxy (ULIG) with an active galactic nucleus, located in the constellation Boötes. With a redshift of 0.121740, the galaxy is located 1.7 billion light-years from Earth.
2MASX J17201001+2637317 also known as PGC 1782937, is a massive type-cD elliptical galaxy located in the constellation of Hercules. With redshift of 0.16, the galaxy is located 2.4 billion light-years from Earth and the brightest cluster galaxy in the galaxy cluster, RX J1720.1+2638.
2MASX J09175344+5143379 also known as PGC 2399018, is a massive elliptical galaxy located in the constellation of Ursa Major. At the redshift of 0.216, the galaxy is located 2.9 billion light-years from Earth and considered the brightest cluster galaxy (BCG) in the galaxy cluster, Abell 773.
The South America Galaxy, also known as LEDA 69877 and IRAS 22491-1808, is a merging pair of ultraluminous infrared galaxies located in the constellation Aquarius. It is estimated to be 1.045 million light-years from the Milky Way and about 90,000 light-years in diameter. The object is moving away from the Solar System with a calculated radial velocity of approximately 23.300 kilometers per second.
