Today marks the 18th anniversary of the launch of the Hubble Space Telescope, and to celebrate, NASA has released a collection of 59 new Hubble images (under the fantastic title “Galxies Gone Wild!”) that present galaxies in all of their volatile wonder.
We see them colliding, merging, spiraling away—all of the things that crazy galaxies do when they get drunk on spring break exist for billions of years in the universe. Thanks to the decision to keep Hubble aloft for another five years (a Shuttle mission planned for this summer will service the telescope for the final time), we can expect greatness from the world’s most famous space telescope well into the next decade.
Arp 148 is the staggering aftermath of an encounter between two galaxies, resulting in a ring-shaped galaxy and a long-tailed companion. The collision between the two parent galaxies produced a shockwave effect that first drew matter into the center and then caused it to propagate outwards in a ring. The elongated companion perpendicular to the ring suggests that Arp 148 is a unique snapshot of an ongoing collision. Infrared observations reveal a strong obscuration region that appears as a dark dust lane across the nucleus in optical light. Arp 148 is nicknamed Mayall s object and is located in the constellation of Ursa Major, the Great Bear, approximately 500 million light-years away. This interacting pair of galaxies is included in Arp’s catalog of peculiar galaxies as number 148.
UGC 9618, also known as VV 340 or Arp 302 consists of a pair of very gas-rich spiral galaxies in their early stages of interaction: VV 340A is seen edge-on to the left, and VV 340B face-on to the right. An enormous amount of infrared light is radiated by the gas from massive stars that are forming at a rate similar to the most vigorous giant star-forming regions in our own Milky Way. UGC 9618 is 450 million light-years away from Earth, and is the 302nd galaxy in Arp’s Atlas of Peculiar Galaxies.
Arp 256 is a stunning system of two spiral galaxies in an early stage of merging. The Hubble image displays two galaxies with strongly disrupted shapes and an astonishing number of blue knots of star formation that look like exploding fireworks. The galaxy to the left has two extended ribbon-like tails of gas, dust and stars. The system is a luminous infrared system radiating more than a hundred billion times the luminosity of our Sun. Arp 256 is located in the constellation of Cetus, the Whale, about 350 million light-years away. It is the 256th galaxy in Arp’s Atlas of Peculiar Galaxies.
NGC 6670 is a gorgeous pair of overlapping edge-on galaxies resembling a leaping dolphin. Scientists believe that NGC 6670 has already experienced at least one close encounter and is now in the early stages of a second. The nuclei of the two galaxies are approximately 50,000 light-years apart. NGC 6670 glows in the infrared with more than a hundred billion times the luminosity of our Sun and is thought to be entering a starburst phase. The pair is located some 400 million light-years away from Earth.
NGC 6240 is a peculiar, butterfly- or lobster-shaped galaxy consisting of two smaller merging galaxies. It lies in the constellation of Ophiuchus, the Serpent Holder, some 400 million light-years away. Observations with NASA s Chandra X-ray Observatory have disclosed two giant black holes, about 3,000 light-years apart, which will drift toward one another and eventually merge together into a larger black hole. The merging process, which began about 30 million years ago, triggered dramatic star formation and sparked numerous supernova explosions. The merger will be complete in some tens to hundreds of millions of years.
ESO 593-8 is an impressive pair of interacting galaxies with a feather-like galaxy crossing a companion galaxy. The two components will probably merge to form a single galaxy in the future. The pair is adorned with a number of bright blue star clusters. ESO 593-8 is located in the constellation of Sagittarius, the Archer, some 650 million light-years away from Earth.
NGC 454 is galaxy pair comprising a large red elliptical galaxy and an irregular gas-rich blue galaxy. The system is in the early stages of an interaction that has severely distorted both components. The three bright blue knots of very young stars to the left of the two main components are probably part of the irregular blue galaxy. Although the dust lanes that stretch all the way to the center of the elliptical galaxy suggest that gas has penetrated that far, no signs of star formation or nuclear activity are visible. The pair is approximately 164 million light-years away.
UGC 8335 is a strongly interacting pair of spiral galaxies resembling two ice skaters. The interaction has united the galaxies via a bridge of material and has yanked two strongly curved tails of gas and stars from the outer parts of their bodies . Both galaxies show dust lanes in their centers. UGC 8335 is located in the constellation of Ursa Major, the Great Bear, about 400 million light-years from Earth. It is the 238th galaxy in Arp’s Atlas of Peculiar Galaxies.
This Hubble image displays a beautiful pair of interacting spiral galaxies with swirling arms. The smaller of the two, dubbed LEDA 62867 and positioned to the left of the frame, seems to be safe for now, but will probably be swallowed by the larger spiral galaxy, NGC 6786 (to the right) eventually. There is already some disturbance visible in both components. The pair is number 538 in Karachentsev’s Catalog of Pairs of Galaxies. A supernova was seen to explode in the large spiral in 2004. NGC 6786 is located in the constellation of Draco, the Dragon, about 350 million light-years away.
This galaxy features a single nucleus, a containing a blue central disk with delicate fine structure in the outer parts and tidal tails indicative of two former disk galaxies. At present these galaxies appear to have completed their merger. The remnant shows clear signs that the merger was gas-rich and accompanied by a starburst. NGC 17 is gas-rich and can sustain its strong central starburst and present mild central activity for some time to come. NGC 17 is located about 250 million light-years away in the constellation of Cetus, the Whale.
IC 4687 forms a triplet with two other galaxies: IC 4686 to the right and IC 4689 further to the right. IC 4687 has a chaotic body of stars, gas and dust and a large curly tail to the left. The two companions are partially obscured by dark bands of dust. The interacting triplet is about 250 million light-years away from Earth, in the constellation of Pavo, the Peacock.
This Hubble image of ESO 77-14 is a stunning snapshot of a celestial dance performed by a pair of similar sized galaxies. Two clear signatures of the gravitational tug of war between the galaxies are the bridge of material that connects them and the disruption of their main bodies. The galaxy on the right has a long, bluish arm while its companion has a shorter, redder arm. This interacting pair is in the constellation of Indus, the Indian, some 550 million light-years away from Earth. The dust lanes between the two galaxy centers show the extent of the distortion to the originally flat disks that have been pulled into three-dimensional shapes.
IC 5298 is a beautiful face-on spiral galaxy with two long arms extending from the central bulge and curving back amongst the scattered stars, gas and dust. A nearby smaller companion is linked by a bridge of matter to the principal galaxy in an interaction reminiscent of the famous Whirlpool Galaxy, M51. There is also a third faint, irregular galaxy, visible at the top of the image that is also linked by a bridge of matter and probably involved in the interaction.
II Zw 96
This is a system of merging galaxies with a bizarre shape. Powerful young starburst regions hang as long threadlike structures between the main galaxy cores. The system almost qualifies as an ultra-luminous system, but has not yet reached the late stage of coalescence that is the norm for most ultra-luminous systems. II Zw 96 is located in the constellation of Delphinus, the Dolphin, about 500 million light-years away from Earth.
2MASX J09133888-1019196 comprises two interacting galaxies that are both disturbed by gravitational interaction. The wide separation of the pair – approximately 130,000 light-years – suggests that the galaxies are just beginning to merge. Together the two galaxies form an ultra-luminous infrared system, which is unusual for the early stages of an interaction. One possible explanation is that the one or both of the components have already experienced a merger or interaction. Giant black holes lurk at the cores of both galaxies, which are found in the constellation of Hydra, the Sea Serpent, about 700 million light-years away from Earth.
This system consists of two interacting spiral galaxies. The galaxy to the left displays a dim plume of luminosity that extends to the right in the direction of the second spiral. Both galaxies are partly obscured by dust lanes. The galaxy at center is adorned with blue knots of stars. IRAS 18090+0130 is located in the constellation of Ophiuchus, the Serpent Holder, some 400 million light-years away from Earth.
IRAS 20351+2521 is a galaxy with a sprawling structure of gas, dust and numerous blue star knots. IRAS 20351+2521 is located in the constellation of Vulpecula, the Fox, 450 million light-years away from Earth.
AM 0500-620 consists of a highly symmetric spiral galaxy seen nearly face-on and partially backlit by a background galaxy. The foreground spiral galaxy has a number of dust lanes between its arms. The background galaxy was earlier classified as an elliptical galaxy, but Hubble has now revealed a galaxy with dusty spiral arms and bright knots of stars. AM0500-620 is 350 million light-years away from Earth in the constellation of Dorado, the Swordfish.
AM 0702 consists of a couple of detached galaxies, far apart and probably only just beginning to interact. The first signs of the interaction are visible in the galaxy on the left, where the outer structure of the spiral arms is starting to expand, extending a tidal tail of matter out into space.
AM 1316-241 is made up of two interacting galaxies – a spiral galaxy (on the left of the frame) in front of an elliptical galaxy (on the right of the frame). The starlight from the background galaxy is partially obscured by the bands and filaments of dust associated with the foreground spiral galaxy. The Hubble image unravels the fine detail in the patchy clumps of dust confined to the spiral arms of the spiral galaxy. This dust reddens the light from the background just as the intervening dust in the Earth’s atmosphere reddens sunsets here. AM1316-241 is located some 400 million light-years away toward the constellation of Hydra, the Water Snake.
Arp 220 appears to be a single, odd-looking galaxy, but is in fact a nearby example of the aftermath of a collision between two spiral galaxies. It is the brightest of the three galactic mergers closest to Earth, about 250 million light-years away in the constellation of Serpens, the Serpent. The collision, which began about 700 million years ago, has sparked a cracking burst of star formation, resulting in about 200 huge star clusters in a packed, dusty region about 5,000 light-years across (about 5 percent of the Milky Way’s diameter). The amount of gas in this tiny region equals the amount of gas in the entire Milky Way Galaxy. The star clusters are the bluish-white bright knots visible in the Hubble image. Arp 220 glows brightest in infrared light and is an ultra-luminous infrared galaxy. Previous Hubble observations, taken in the infrared at a wavelength that looks through the dust, have uncovered the cores of the parent galaxies 1,200 light-years apart. Observations with NASA s Chandra X-ray Observatory have also revealed X-rays coming from both cores, indicating the presence of two supermassive black holes. Arp 220 is the 220th galaxy in Arp’s Atlas of Peculiar Galaxies.
This system is an interacting galaxy pair. The interaction has disturbed both galaxies: the lower galaxy has a bizarre structure and a tidal tail emerges from the main body of the upper galaxy. The galaxy pair lies in a crowded field of Milky Way stars. IRAS 21101+5810 is located in the constellation of Cepheus, the King, about 550 million light-years away from Earth.
CGCG 436-030, the eye-catching spiral galaxy in the image, shows a very pronounced curling tail. The companion galaxy, located to the bottom-right of the image, displays an intricate structure, including a number of trails that extend quite far out from its core. The bright star that appears between the two galaxies does not belong to the interacting system and is located within the Milky Way. CGCG 436-030 is located in the constellation of Pisces, the Fish, about 400 million light-years away.
MCG+08-11-002 is an odd-looking galaxy with a spectacular dark band of absorbing dust in front of the galaxy’s center, making it resemble a “Black Eye”. Scientists believe that it is the remnant of an earlier collision of two separate galaxies. This peculiar galaxy is at the center of a rich field of foreground stars, close to the plane of our own Milky Way galaxy. MCG+08-11-002 is about 250 million light-years away in the constellation of Auriga, the Charioteer.
MCG+12-02-001 consists of a pair of galaxies visibly affected by gravitational interaction as material is flung out in opposite directions. A large galaxy can be seen at the top of the frame and a smaller galaxy resembling an erupting volcano is at the bottom. The bright core of this galaxy emerges from the tip of the volcano . MCG+12-02-001 is a luminous infrared system that radiates with more than a hundred billion times the luminosity of our Sun. It is located some 200 million light-years away from Earth toward the constellation of Cassiopeia, the Seated Queen.
The galaxies of this beautiful interacting pair bear some resemblance to musical notes on a stave. Long tidal tails sweep out from the two galaxies: gas and stars were stripped out and torn away from the outer regions of the galaxies. The presence of these tails is the unique signature of an interaction. ESO 69-6 is located in the constellation of Triangulum Australe, the Southern Triangle, about 650 million light-years away from Earth.
ESO 99-4 is a galaxy with a highly peculiar shape that is probably the remnant of an earlier merger process that has deformed it beyond visual recognition, leaving the main body largely obscured by dark bands of dust. ESO 99-4 lies in a rich field of foreground stars, in the constellation of Triangulum Australe, the Southern Triangle, about 400 million light-years away.
Markarian 273 is a galaxy with a bizarre structure that somewhat resembles a toothbrush. The Hubble image shows an intricate central region and a striking tail that extends diagonally towards the bottom-right of the image. The tail is about 130 thousand light-years long and is strongly indicative of a merger between two galaxies. Markarian 273 has an intense region of starburst, where 60 solar masses of new stars are born each year. Near-infrared observations reveal a nucleus with two components. Markarian 273 is one of the most luminous galaxies when observed in the infrared, and is located 500 million light-years away from Earth.
NGC 695 is a peculiar galaxy which looks like a revolving tornado. It is a disturbed spiral galaxy, seen face-on, with loosely wound spiral arms. Knotty star-forming regions are tangled in a mesh of dust and gas. NGC 695 is in an interaction with a small companion located just outside the image to the left. Scientists believe that this is a recent but relatively weak interaction. NGC 695 is located in the constellation of Aries, the Ram, about 450 million light-years away from Earth.
The galaxy system NGC 1614 has a bright optical center and two clear inner spiral arms that are fairly symmetrical. It also has a spectacular outer structure that consists principally of a large one-sided curved extension of one of these arms to the lower right, and a long, almost straight tail that emerges from the nucleus and crosses the extended arm to the upper right. The galaxy appears to be the result of a tidal interaction and the resulting merger of two predecessor systems. The system has a nuclear region of quasar-like luminosity, but shows no direct evidence for an active nucleus. It is heavily and unevenly reddened across its nucleus, while infrared imaging also shows a ridge of dust. The linear tail to the upper right and extended arms to the lower right are likely the remains of an interacting companion and the tidal plume(s) caused by the collision. NGC 1614 is located about 200 million light-years away from Earth in the constellation of Eridanus, the River.
ESO 148-2 is a beautiful object that resembles an owl in flight. It consists of a pair of former disk galaxies undergoing a collision. The cores of the two individual galaxies – seen at the center of the image – are embedded in hot dust and contain a large number of stars. Two huge wings sweep out from the center and curve in opposite directions. These are tidal tails of stars and gas that have been pulled from the easily distorted disks of the galaxies. This cosmic owl is one of the most luminous infrared galaxies known and is located some 600 million light-years away from Earth.
NGC 3256 is an impressive example of a peculiar galaxy that is actually the relict of a collision of two separate galaxies that took place in a distant past. The telltale signs of the collision are two extended luminous tails swirling out from the galaxy. NGC 3256 belongs to the Hydra-Centaurus supercluster complex and provides a nearby template for studying the properties of young star clusters in tidal tails. The system hides a double nucleus and a tangle of dust lanes in the central region. The tails are studded with a particularly high density of star clusters.
IC 694 and NGC 3690
This system consists of a pair of galaxies, dubbed IC 694 and NGC 3690, which made a close pass some 700 million years ago. As a result of this interaction, the system underwent a fierce burst of star formation. In the last fifteen years or so six supernovae have popped off in the outer reaches of the galaxy, making this system a distinguished supernova factory. Arp 299 belongs to the family of ultra-luminous infrared galaxies and is located in the constellation of Ursa Major, the Great Bear, approximately 150 million light-years away. It is the 299th galaxy in Arp’s Atlas of Peculiar Galaxies. Despite its enormous amount of absorbing dust, enough violet and near-ultraviolet light leaks out for it to be number 171 in B.E. Markarian’s catalog of galaxies with excess ultraviolet emission.
NGC 5256, also known as Markarian 266, is a striking example of two disk galaxies that are about to merge. Spectacular streamers of gas surround the two nuclei and eye-catching blue spiral trails indicate recent star formation. The shape of the object is highly disturbed and observations in various wavelength regimes — infrared, millimeter-wave and radio — provide additional evidence for a starburst in this system. NGC 5256 is located in the constellation of Ursa Major, the Great Bear, some 350 million light-years from Earth. Each galaxy also contains an active galactic nucleus, evidence that the chaos is allowing gas to fall into the regions around central black holes as well as feeding starbursts. Recent observations from the Chandra X-ray Observatory show that both nuclei, as well as a region of hot gas in between them, have been heated by the shock waves driven as gas clouds at high velocities collide.
ESO 239-2 is most likely the result of a cosmic collision or a lengthy merger process that will eventually result in an elliptical galaxy. The messy intermediate stage, captured here, is a galaxy with long, tangled tidal tails that envelope the galaxy’s core.
ESO 255-7 consists of a quartet of interacting galaxies. Three or four galaxies are embedded in a common structure with an arc-like shape. The upper part of this structure appears almost like one single galaxy but has in fact two component galaxies. The lowest galaxy is substantially obscured by dust. The interacting group is about 550 million light-years away from Earth, in the constellation of Puppis, the Stern.
ESO 286-19 is a peculiar galaxy that consists of what were originally two disk galaxies that are now in the midst of an ongoing collision. It has undergone a burst of star formation that ended about eight million years ago. ESO 286-19 has a long tail to the right of the main body, and a shorter tail curving to the left. The presence of the tails is a unique signature of the merger process: gas and stars were stripped out by rippling gravitational pulls as the galaxies collided and the outer regions of the parent galaxies were torn off. These tidal tails can persist long after the galaxies have finally merged. ESO 286-19 is located 600 million light-years away from Earth and is an exceptionally luminous source of infrared radiation.
ESO 507-70 is an odd-looking galaxy that is probably the remnant of an earlier merger process. It is a chaotic swirl of gas, dust and stars with no sign of the conjectured original spiral or elliptical structure, now lost and distorted beyond recognition in a gravitational encounter with another galaxy. ESO 507-70 is some 300 million light-years away from Earth toward the constellation of Hydra, the Water Snake.
NGC 5257/8 (Arp 240) is an astonishing galaxy pair, composed of spiral galaxies of similar mass and size, NGC 5257 and NGC 5258. The galaxies are visibly interacting with each other via a bridge of dim stars connecting the two galaxies, almost like two dancers holding hands while performing a pirouette. Both galaxies harbor supermassive black holes in their centers and are actively forming new stars in their disks. Arp 240 is located in the constellation Virgo, approximately 300 million light-years away, and is the 240th galaxy in Arp’s Atlas of Peculiar Galaxies. With the exception of a few foreground stars from our own Milky Way all the objects in this image are galaxies.
ESO 550-2 shows a pair of spiral galaxies, the larger nearly face-on and accompanied by a smaller, highly tilted partner. Tidal interaction from the smaller companion has clearly deformed one arm of the larger galaxy. Strong star formation continues both in the deformed arm and in a ring structure around the galaxy’s core. The pair is surrounded by the glow of faintly shining stars and interstellar matter that has been smeared through space by the gravitational effects of the collision and the pull of a third nearby galaxy.
NGC 5754 and NGC 5752
This beautiful pair of interacting galaxies consists of NGC 5754, the large spiral on the right, and NGC 5752, the smaller companion in the bottom left corner of the image. NGC 5754’s internal structure has hardly been disturbed by the interaction. The outer structure does exhibit tidal features, as does the symmetry of the inner spiral pattern and the kinked arms just beyond its inner ring. In contrast, NGC 5752 has undergone a starburst episode, with a rich population of massive and luminous star clusters clumping around the core and intertwined with intricate dust lanes. The contrasting reactions of the two galaxies to their interaction are due to their differing masses and sizes. NGC 5754 is located in the constellation Bootes, the Herdsman, some 200 million light-years away.
NGC 6090 is a beautiful pair of spiral galaxies with an overlapping central region and two long tidal tails formed from material ripped out of the galaxies by gravitational interaction. The two visible cores are approximately 10,000 light-years apart, suggesting that the two galaxies are at an intermediate stage in the merging process. The Hubble image reveals bright knots of newborn stars in the region where the two galaxies overlap. The right hand component has a clear spiral structure if viewed face-on, while the other is seen edge-on with no spiral arms visible. NGC 6090 is located in the constellation of Draco, the Dragon, about 400 million light-years away from Earth. A number of fainter, and more distant, background galaxies is seen in the image. This system has much in common with the famous Antennae galaxies both in terms of how far the merger has progressed and in our viewing angle.
IC 883 displays a very disturbed, complex central region with two tidal tails of approximately the same length emerging at nearly right angles: one diagonally to the top right of the frame and the other to the bottom right. The twin tidal tails suggest that IC 883 is the remnant of the merger of two gas-rich disk galaxies. The collision appears to have triggered a burst of star formation, indicated by a number of bright star clusters in the central region. IC 883 is 300 million light-years away toward the constellation of Canes Venatici, the Hunting Dogs. It is Number 193 in Arp’s Atlas of Peculiar Galaxies.
NGC 6621/2 (VV 247, Arp 81) is a strongly interacting pair of galaxies, seen about 100 million years after their closest approach. It consists of NGC 6621 (to the left) and NGC 6622 (to the right). NGC 6621 is the larger of the two, and is a very disturbed spiral galaxy. The encounter has pulled a long tail out of NGC 6621 that has now wrapped behind its body. The collision has also triggered extensive star formation between the two galaxies. Scientists believe that Arp 81 has a richer collection of young massive star clusters than the notable Antennae galaxies (which are much closer than Arp 81). The pair is located in the constellation of Draco, approximately 300 million light-years away from Earth. Arp 81 is the 81st galaxy in Arp’s Atlas of Peculiar Galaxies.
IC 1623 is an interacting galaxy system that is very bright when observed in the infrared. One of the two galaxies, the infrared-bright, but optically obscured galaxy VV 114E, has a substantial amount of warm and dense gas. Warm and dense gas is also found in the overlap region connecting the two nuclei. Observations further support the notion that IC 1623 is approaching the final stage of its merger, when a violent central inflow of gas will trigger intense starburst activity that could boost the infrared luminosity above the ultra-luminous threshold. The system will likely evolve into a compact starburst system similar to Arp 220. IC 1623 is located about 300 million light-years away from Earth.
IC 2545 is a beautiful, but deceptive object that appears to be a single S-shaped galaxy, but is actually a pair of merging galaxies. The two cores of the parent galaxies are still visible in the central region. Other telltale markers for the collision include two pronounced tidal arms of gas and stars flung out from the central region. The tidal arm curving upwards and clockwise in the image contains a number of blue star clusters. IC 2545 glows strongly in the infrared part of the spectrum – another sign that it is a pair of merging galaxies. It lies in the constellation of Antlia, the Air Pump, some 450 million light-years away from Earth.
NGC 7674 (seen just above the center), also known as Markarian 533, is the brightest and largest member of the so-called Hickson 96 compact group of galaxies, consisting of four galaxies. This stunning Hubble image shows a spiral galaxy nearly face-on. The central bar-shaped structure is made up of stars. The shape of NGC 7674, including the long narrow streamers seen to the left of and below the galaxy can be accounted for by tidal interactions with its companions. NGC 7674 has a powerful active nucleus of the kind known as a type 2 Seyfert that is perhaps fed by gas drawn into the center through the interactions with the companions. NGC 7674 falls into the family of luminous infrared galaxies and is featured in Arp’s Atlas of Peculiar Galaxies as number 182. It is located in the constellation of Pegasus, the Winged Horse, about 400 million light-years away from Earth.
IC 2810 is a disk galaxy viewed nearly edge-on. It is slightly disturbed by gravitational interaction with a smaller, dusty companion (located to the bottom of the image). The larger galaxy shows blue knots of star formation. Although the pair has no overlapping region at present, it is possible that the two will eventually collide in the future. IC 2810 is located in the constellation of Leo, the Lion, about 450 million light-years away.
UGC 4881, known as the “The Grasshopper,” is a stunning system consisting of two colliding galaxies. It has a bright curly tail containing a remarkable number of star clusters. The galaxies are thought to be halfway through a merger the cores of the parent galaxies are still clearly separated, but their disks are overlapping. A supernova exploded in this system in 1999 and astronomers believe that a vigorous burst of star formation may have just started. This notable object is located in the constellation of Lynx, some 500 million light-years away from Earth. UGC 4881 is the 55th galaxy in Arp’s Atlas of Peculiar Galaxies.
UGC 5101 is a peculiar galaxy with a single nucleus contained within an unstructured main body that suggests a recent interaction and merger. UGC 5101 is thought to contain an active galactic nucleus an extremely bright, compact core – buried deep in the gas and dust. A pronounced tail extends diagonally to the top-right of the frame. A fainter halo of stars surrounds the galaxy and is visible in the image, due to Hubble s ability to collect and detect faint light. This halo is probably a result of the earlier collision. UGC 5101 is about 550 million light-years away from Earth.
The extraordinary galaxy UGC 8058, also known as Markarian 231, was discovered in 1969 as part of a survey searching for galaxies with strong ultraviolet radiation. It has long tidal tails and a disturbed shape. Results from the first spectrum showed clear signs of the presence of a powerful quasar in the center that made Markarian 231 unique in the Markarian sample. Markarian 231 has maintained its reputation as an exceptional object since those early observations and continues to be a favorite target in all wavelength regimes. Its infrared luminosity is similar to that of quasars, making it one of the most luminous and powerful known ultra-luminous infrared galaxies. Although the emission of many ultra-luminous infrared galaxies appears to be dominated by energetic starbursts, Markarian 231 has been repeatedly identified as an exception and many pieces of evidence point toward an accreting black hole as the major power source behind the enormous infrared luminosity. Although the primary power source behind the incredible far-infrared luminosity of Markarian 231 is almost certainly an active nucleus, the galaxy is also undergoing an energetic starburst. Most dramatically a nuclear ring of active star formation with a rate estimated to be greater than 100 solar masses per year has been found in the center. UGC 8058 is located about 600 million light-years away from Earth.
UGC 12812, also known as Markarian 331, is a spiral galaxy with no obvious tidal tails. It is located in the lower part of the Hubble image. Two neighboring blue galaxies are seen at the top of the frame. The galaxy at the very top is embellished by a remarkable number of blue star knots. Observations point to the presence of a giant black hole anchored at the center of the bright core of UGC 12812. The galaxy produces 80 solar masses of new stars on average every year. It is an open question whether Markarian 331 is actually a merging system or whether its infrared brightness stems from another process. UGC 12812 is located in the constellation of Pegasus, the Winged Horse, about 250 million light-years away from Earth.
VV 283 looks like a single peculiar galaxy, but is in fact a pair of merging galaxies. A tidal tail swirls out from a messy central region and splits into two branches. The upward twisting branch is brightened by luminous blue star knots. Like many merging systems, VV 283 is a very luminous infrared system, radiating nearly one thousand billion times energy more than our Sun. VV 283 is located in the constellation of Virgo, the Maiden, some 500 million light-years away.
VV 705, or Markarian 848, consists of two galaxies that seem to be embracing each other. Two long, highly curved arms of gas and stars emerge from a central region with two cores. One arm, curving clockwise, stretches to the top of the image where it makes a U-turn and interlocks with the other arm that curves up counter-clockwise from below. The two cores are 16,000 light-years apart. The pair is thought to be midway through a merger. Markarian 848 is located in the constellation of Bootes, the Bear Watcher, and is approximately 550 million light-years away from Earth.