Video Credit: Deep Sky Videos
Double Quasars
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Tag Archives: Galactic Mergers
Mergers and Acquisitions
NGC 1512 is a barred spiral galaxy with an unusual double ring structure, one ring around the galactic nucleus and another further out in the main disk. It’s about 38 million light-years away in the constellation Horologium. It’s on a collision course to merge with its smaller neighbor NGC 1510 (on the far right in the picture).
Image Credit: ESA / NASA
Mergers and Acquisitions
As the two spiral galaxies in Apr 220 collide, they’re glowing in infrared with the light of more than a trillion suns. The merger of the galaxies has ignited a tremendous burst of star birth, and each galactic core is surrounded by a star-forming ring JWST has captured in infrared.
Image Credits: NASA / ESA / CSA / STScI / Alyssa Pagan (STScI)
A Runaway Black Hole
Video Credit: NASA
Mergers and Acquisitions
The three galaxies just right of center—known to astronomers as SDSSCGB 10189—are on collision courses and will eventually merge into a single larger galaxy, distorting each other’s spiral structure through gravitational interaction. They are a relatively rare combination of three large star-forming galaxies lying within only 50,000 light-years of one another. Taht makes them extremely close neighbors. Our own large galactic neighbors are much further away; Andromeda is more than 2.5 million light-years away from the Milky Way.
An unrelated foreground galaxy appears to the left, and the smudged shapes of much more distant galaxies are visible in the background.
Image Credit: NASA / ESA
A Pair of Mice
NGC 4676, or the Mice Galaxies, are a pair of spiral galaxies in the constellation Coma Berenices, about 290 million light-years away. They are in the process of colliding and merging. Their name refers to the long tails produced by their tidal action on each other.
The colors of the galaxies are unusual. The dark core of NGC 4676A a is surrounded by a bluish white remnant of spiral arms. It tail starts out blue and ends in a more yellowish color. In most galaxies the spiral arms are yellow near the core yellow and become more blue at their ends. NGC 4676B has a yellowish core blue remnants of a pair of spiral arms.
Image Credit: NASA
A Prospective Merger
This pair of galaxies, called MRK 1034, lies in the constellation of Triangulum (The Triangle) in the northern sky. The two similar galaxies, PGC 9074 and PGC 9071, are close enough to one another to be tied together by gravity, but because we are seeing them as they are just beginning to interact gravitationally, there aren’t any large distortions noticeable. Yet. Wait a few hundred million years.
We see both spiral galaxies top down from our point of view. At the bottom PGC 9074 shows a bright bulge and two spiral arms tightly wound around its nucleus, features which classify it as a type Sa galaxy. PGC 9071 isa type Sb galaxy with a fainter bulge and the spiral arms further apart. The spiral arms of both show dark patches of dust mixed with blue clusters of recently-formed stars. Older, cooler stars can be found in the glowing, compact yellowish bulge towards the galactic centers, and each galaxy is surrounded by a much fainter round halo of old stars.
So what would we likely see after waiting a few hundred million years? As these two neighbors attract each other, the process of star formation will be increased, and tidal forces will throw out long tails of stars and gas. Eventually, the interacting galaxies should merge together into a new, larger galaxy.
Image Credit: NASA
Mergers and Acquisitions
Over next couple of billion years, these two spiral galaxies will end up in a complete galactic merger—the two galaxies will become a single, larger one. They’re about 150 million light-years away in the constellation of Canis Major (the Great Dog). The gravitational attraction of NGC 2207, the larger of the pair, is already stirring things up throughout its smaller partner, distorting IC 2163’s shape and throwing stars and gas into long streamers that extend over 100,000 light-years. However, most of the space between stars in a galaxy is empty. When these galaxies collide, almost none of the stars in them will crash into another star.
Image Credit: ESO
Mergers and Acquisitions
This is a collision between two galaxies—a spiral galaxy and a lenticular galaxy. There’s an almost 3D appearance to the picture as the spiral arms embrace the lenticular galaxy’s bulge.
There’s more evidence of the collision in the image. Look at the stream of stars coming out from the merging galaxies toward the top of the image. The bright spot in the middle of the plume is the unique feature of this collision. That spot is believed to be the former nucleus of the spiral galaxy ejected from the system during the collision. It’s now being disassembled by tidal forces producing the stream of stars.
Image Credit: NASA
Coming Together and Coming Apart
This composite image of the Whirlpool Galaxy and it’s nearby companion galaxy overlays radio astronomy data from the Very Large Array with optical data. The image in white shows how the galaxies appear to optical telescopes: one giant spiral galaxy with a smaller one hanging off an arm. The VLA sees a much bigger picture. The blue overlay reveals the the cast-off gases that were once in the outer spiral arms of these galaxies which have been pulled apart as the smaller galaxy has moved passed the larger one.
Image Credit: NRAO
Mergers and Acquisitions
This is an odd galaxy known as NGC 1487. It’s not a single galaxy but two or more galaxies in the act of merging. Each of the old galaxies has lost almost all traces of its original appearance as the stars and gas have been thrown about by gravitational interactions. Unless one of the merging galaxies is very much bigger than the other(s), galaxies are always disrupted by the violence of the merging process, so it’s essentially impossible to determine exactly what the original galaxies looked like or how many of them there were. In this case, it may be that this NGC 1487 is the merger of several dwarf galaxies that were previously part of a small group.
Although older yellow and red stars can be seen in the outer regions of the new galaxy, its general appearance is dominated by bright blue stars that probably formed in a burst of star formation triggered by the merger.
Image Credit: ESA / NASA
Mergers and Acquisitions
ESA published this montage of galactic mergers as seen by Hubble.
Video Credit: ESA
Mergers and Acquisitions
In this image, galaxy NGC 2799 appears to being pulled into the center of its neighbor NGC 2798. Interacting galaxies such as these may eventually merger or form a unique pairing. For now, stars from NGC 2799 seem to be falling into NGC 2798 almost like droplets of water.
Galactic mergers usually take place over time scales of several hundred million to a billion or more years. While one or both of the galaxies may cease to exist as an independent entity, the vast space between stars means that stellar collisions are unlikely, so the individual stars typically drift past each other. Our Milky Way is on track to merge with the Andromeda galaxy in four billion years or so.
Image Credit: NASA / ESA
A 3D View of a Galactic Merger
This animation shows a #D rendering of a gas halo observed by ESO’s Very Large Telescope superimposed over an older image of a galaxy merger obtained with ESO’s Atacama Large Millimeter Array. The halo of hydrogen gas is shown in blue, and the ALMA data is shown in orange. The halo is bound to the galaxy, which contains a quasar at its center. The gas in the halo provides the perfect food source for the supermassive black hole at the centre of the quasar.
The redshift on these objects is 6.2, meaning we see them as they were 12.8 billion years ago.
Video Credit: ESO
Mergers and Acquisitions
Video Credit: ESO