Space images thread

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This image, taken by the NASA/ESA Hubble Space Telescope, shows a peculiar galaxy known as NGC 1487, lying ~ 30 million ly away in the southern constellation of Eridanus.

Rather than viewing a celestial object, it is actually better to think of this as an event. Here, we are witnessing two or more galaxies in the act of merging together to form a single new galaxy. Each progenitor has lost almost all traces of its original appearance, as stars and gas have been thrown hither and thither by gravity in an elaborate cosmic whirl.

Unless one is very much bigger than the other, galaxies are always disrupted by the violence of the merging process. As a result, it is very difficult to determine precisely what the original galaxies looked like and, indeed, how many of them there were. In this case, it is possible that we are seeing the merger of several dwarf galaxies that were previously clumped together in a small group.

Although older yellow and red stars can be seen in the outer regions of the new galaxy, its appearance is dominated by large areas of bright blue stars, illuminating the patches of gas that gave them life. This burst of star formation may well have been triggered by the merger.

 

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Emission nebula IC 4628 [aka Prawn Nebula and Gum 56] lies ~ 6000 ly away in the constellation of Scorpius. These types of nebulae arise when a sun-like star at the end of its life spews forth an enormous amount of gas. The remaining star, a white dwarf, emits intense ultra-violet light that causes the gas to glow, with different elements of the gas displaying different colors. Red indicates ionized hydrogen, and near the central star, doubly ionized oxygen glows in green.

This stunning short sequence zooms in on the open young cluster of stars Trumpler 14

 

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Located ~ 1 billion ly away in the constellation of Eridanus, galaxy LO95 0313-192 has a spiral shape similar to that of the Milky Way. It has a large central bulge, and arms speckled with brightly glowing gas mottled by thick lanes of dark dust. Its companion, sitting in the right of the frame, is known rather unpoetically as [LOY2001] J031549.8-190623.

Jets, outbursts of superheated gas moving at close to the speed of light, have long been associated with the cores of giant elliptical galaxies, and galaxies in the process of merging. However, in an unexpected discovery, astronomers found LO95 0313-192, even though it is a spiral galaxy, to have intense radio jets spewing out from its center.

 

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A binary star pair within the Trapezium Cluster

Dwarf Galaxy IC 1613 (image is on the previous page)

 

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I once posted a picture of Flame Nebula. Here are some new and unseen pictures of Flame Nebula:

While Orion is known for its belt of three bright stars, the constellation is actually part of the Orion Molecular Cloud Complex which is much more involved, and beautiful, than meets the eye, as seen in the above image. This deep exposure shows many invisible details from the Flame Nebula glowing excitedly in the lower left and the dark Horsehead Nebula just to its right; to the star-birthing Orion Nebula in the upper right corner neighboring the Running Man with its blue stars.

Two other images of Flame Nebula taken by WISE:

Flame Nebula sits on the eastern hip of Orion.

This image shows a vast cloud of gas and dust where new stars are being born. Three familiar nebulae are visible in the central region: the Flame Nebula, the Horsehead Nebula and NGC 2023. The Flame Nebula is the brightest and largest in the image. It is lit by a star inside it that is 20 times the mass of the sun and would be as bright to our eyes as the other stars in Orion's belt if it weren't for all the surrounding dust, which makes it appear 4 billion times dimmer than it actually is.

 

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Artist's impression of W2246-0526, a galaxy shining in infrared with the luminosity of 350 trillion suns.

If anyone is curious to read about it

http://arstechnica.com/science/2016/02/alma-peers-inside-the-brightest-known-quasar/

 

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An old image of:

an intergalactic "pipeline" of material flowing between two battered galaxies that bumped into each other ~ 100 million years ago.

The pipeline [the dark string of matter] begins in NGC 1410 [the galaxy at left], crosses over 20000 ly of intergalactic space, and wraps around NGC 1409 [the companion galaxy at right] like a ribbon around a package.

NGC 1409 is seemingly unaware that it is gobbling up a steady flow of material. A stream of matter funneling into the galaxy should have fueled a spate of star birth. But astronomers don't see it. They speculate that the gas flowing into NGC 1409 is too hot to gravitationally collapse and form stars.

Astronomers also believe that the pipeline itself may contribute to the star-forming draught. The pipeline, a pencil-thin, 500 ly-wide string of material, is moving a mere 0.02 solar masses of matter a year.

Astronomers estimate that NGC 1409 has consumed only ~ a million solar masses of gas and dust, which is not enough material to spawn some of the star-forming regions seen in our Milky Way.

The glancing blow between the galaxies was enough, however, to toss stars deep into space and ignite a rash of star birth in NGC 1410. The arms of NGC 1410, an active, gas-rich spiral galaxy classified as a Seyfert, are awash in blue, the signature color of star-forming regions. The bar of material bisecting the center of NGC 1409 also is a typical byproduct of galaxy collisions.

Astronomers expect more fireworks to come. The galaxies are doomed to continue their game of "bumper cars," hitting each other and moving apart several times until finally merging in another 200 million years. The galaxies' centers are only 23000 ly apart, which is slightly less than Earth's distance from the center of the Milky Way. They are bound together by gravity, orbiting each other at 1 million km/h. The galaxies reside about 300 million ly from Earth in the constellation Taurus.

 

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Scientists measured the temperature of large dust grains around the young star 2MASS J16281370-2431391 in the Rho Ophiuchi star formation region, ~ 400 ly from us.

The astronomers used ALMA to observe the glow coming from carbon monoxide molecules in the 2MASS J16281370-2431391 protoplanetary disc.
They derived a disc dust grain temperature of only -266 degrees Celsius (only 7 K) at a distance of ~ 15 billion km (100 AU) from the central star. This is the first direct measurement of the temperature of large grains (with sizes of ~ 1 mm) in such objects.

 

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Astronomers succeeded in revealing the detailed structure of a massive ionized gas outflow streaming from the starburst galaxy NGC 6240 (located 350 million ly from us). The ionized gas the astronomers observed extends across 300000 ly and is carried out of the galaxy by a powerful superwind. That wind is driven by intense star-forming activity at the galactic center. The star formation rate of NGC 6240 is 25-80 times that of our galaxy.

NGC 6240 has a peculiar, disturbed morphology which indicates that two spiral galaxies are merging. Due to the giant starburst at its heart as a result of the merger, NGC 6240 is very bright in infrared light being emitted from heated dust. The total infrared luminosity is almost a trillion times that of the Sun.

NGC 6240 has experienced violent starbursts at least three times in the past and each starburst drove an energetic superwind. The oldest starburst started ~ 80 million years ago. Astronomers think that the galaxy merger process of NGC 6240 began ~ a billion years ago.

 

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NGC 6193 & 6231: Open Star Clusters

NGC 6193 is a large open star cluster in the constellation of Ara. It's located ~ 3800 ly away from us and it's unusually rich in close binary stars.
Intense UV light streams from the hottest stars in the cluster HD 150135 & HD 150136 - heating up and illuminating their gaseous surroundings, and thus making it shine brightly.

The other open star cluster in this image, NGC 6231, is located at the south-western bend of the Scorpion's tail. This young cluster, only ~ 6.5 million years old, is approaching us at the speed of 100 000 km/h. Its hottest star, Zeta1 Scorpii, is one of the most massive stars in the Milky Way galaxy.

Scientists discovered the brightest ultra metal-poor star ever, 2MASS J18082002–5104378

 

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Galaxy NGC 3675

This image highlights the hidden spiral arms (blue) that were discovered around the nearby galaxy NGC 4625.

The image is composed of UV and visible-light data, from the Galaxy Evolution Explorer and the California Institute of Technology's Digitized Sky Survey, respectively. Near-ultraviolet light is colored green; far-ultraviolet light is colored blue; and optical light is colored red.

As the image demonstrates, the lengthy spiral arms are nearly invisible when viewed in optical light while bright in ultraviolet. This is because they are bustling with hot, newborn stars that radiate primarily UV light.

The youthful arms are also very long, stretching out to a distance four times the size of the galaxy's core. They are part of the largest ultraviolet galactic disk discovered so far.

Located 31 million ly away in the constellation Canes Venatici, NGC 4625 is the closest galaxy ever seen with such a young halo of arms. It's slightly smaller than our Milky Way, both in size and mass. However, the fact that this galaxy's disk is forming stars very actively suggests that it might evolve into a more massive and mature galaxy resembling our own.

The armless companion galaxy seen below NGC 4625 is called NGC 4618. Astronomers don't know why it lacks arms but speculate that it may have triggered the development of arms in NGC 4625.

 

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The nearby spiral galaxy NGC 4450

The picture reveals nothing unusual in the galaxy center. Yet, astronomers have measured wildly rotating gas in a disk around the center of the galaxy. There the gas is moving 30 times faster than anywhere else in the galaxy. This gas rotation centered on the supermassive black hole is illustrated with colors. Red is receding gas and blue is approaching gas. These colors correspond to the physical effect of Doppler shift also known as redshift in astronomy.

Bipolar nebula Hen 2-437 is located within the faint northern constellation of Vulpecula. The material ejected by the dying star has streamed out into space to create the two spectacularly symmetrical icy blue lobes.

 

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The image shown here is a compact group of galaxies HCG 40 at a distance of 300 million ly in the constellation of Hydra. From top to bottom, the 5 galaxies in the group are a spiral, an elliptical, two more spirals, and a lenticular (S0). They clearly appear to be touching each other.

Interactions often occur in compact groups where galaxies are located so close to each other. Evidence of tidal interaction as a result of mutual gravitational attraction is actually seen in all 3 spiral galaxies in this group. The S0 galaxy at the bottom also shows evidence of interaction at its nucleus. Two blueish white dots in the image are stars in our own Galaxy. Small reddish objects are galaxies located billions of light years away. They appear redder than the members of HCG 40 because of the Doppler effect caused by the expansion of the Universe.

Zooming in on the star cluster NGC 3572

 

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Spiral Galaxy M98

An international team led by researchers from the Laboratoire d'Astrophysique de Marseille has observed NGC 4569, the most massive spiral galaxy in the Virgo cluster (at 45 million ly, the massive cluster of galaxies closest to the Milky Way). NGC 4569 is moving through the cluster at a staggering 1200 km/s. The H-alpha image shows for the first time spectacular tails of ionized gas that extend for > 300000 ly, 5 times larger than NGC 4569 itself ! This observation confirms that ram pressure stripping due to the intracluster medium is depriving NGC 4569 of its gas reservoir. An estimate of the mass of gas in these tails shows that 95% of the interstellar medium has already been removed from the disk of the galaxy, greatly limiting its ability to form new stars.

 

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Barred spiral galaxy Dwingeloo 1. Probably one of the largest and nearest galaxies (10 million ly away), but undiscovered until 1994. This is because it's hidden behind the disk of our galaxy - as a result > 99% of its light is absorbed by dust in our galaxy before it reaches us.

 

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New image!

The glowing region in this new image is a reflection nebula known as IC 2631. IC 2631 is the brightest nebula in the Chamaeleon Complex. The complex lies ~ 500 ly away in the southern constellation of Chamaeleon.

IC 2631 is illuminated by the star HD 97300, one of the youngest - as well as most massive and brightest - stars in its neighborhood. This region is full of star-making material, which is made evident by the presence of dark nebulae noticeable above and below IC 2631 in this picture. Dark nebulae are so dense with gas and dust that they prevent the passage of background starlight.

Reflection nebula, like the one spawned by HD 97300, merely scatter starlight back out into space. Starlight that is more energetic, such as the ultraviolet radiation pouring forth from very hot new stars, can ionize nearby gas, making it emit light of its own. These emission nebulae indicate the presence of hotter and more powerful stars, which in their maturity can be observed across thousands of light-years. HD 97300 is not so powerful, and its moment in the spotlight is destined not to last.

Download original image (248 MB)

 

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NGC 6530 is a cluster of 50-100 stars which formed ~ 2 million years ago from the gas clouds of the Lagoon Nebula, a part of which can be seen in the background. The hottest and most massive cluster member is ~ 40-50 times as massive as our sun, and is hundreds of thousands of times brighter.

NGC 6744 is a large face-on barred spiral galaxy in the star-rich southern constellation of Pavo. It lies at a distance of ~ 30 million ly, and is almost 150 000 ly across. Its overall appearance, shape and size are very much like our own Milky Way galaxy. Like our galaxy, it contains > 100 billion stars. Stars like our own sun are far too insignificant to show up individually in this picture – they can only contribute to the general glow.

The bright nucleus of NGC 6744, as other spiral galaxies, is dominated by older reddish and yellowish stars, while the widely and thinly spreading spiral arms are home to bluer and younger stars. Hot star-forming regions, called HII regions for the ionized hydrogen gas they contain, are evident as fuzzy blue spots along the spiral arms. Dark lanes and patches show dust which is obscuring the light of the stars.


Both images by SALT (Southern African Large Telescope)

 

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The Seyfert Galaxy M77 (image by University of Arizona)

Located ~ 300 million ly away in the Coma Cluster, the giant elliptical galaxy NGC 4889, the brightest and largest galaxy in this image, is home to a record-breaking supermassive black hole. 21 billion times the mass of the Sun, this black hole has an event horizon with a diameter of ~ 130 billion km (~ 15 times the diameter of Neptune's orbit from the Sun). By comparison, the supermassive black hole at the center of our galaxy is believed to have a mass about 4 million times that of the Sun and an event horizon just 1/5 the orbit of Mercury.

During its active period, astronomers would have classified NGC 4889 as a quasar and the disc around the supermassive black hole would have emitted up to 1000 times the energy output of the Milky Way.

 

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NGC 4874 is a giant elliptical galaxy, ~ 10 times larger than the Milky Way, at the center of the Coma Galaxy Cluster. With its strong gravitational pull, it is able to hold onto > 30 000 globular clusters, more than any other galaxy that we know of, and even has a few dwarf galaxies in its grasp.

NGC 4874 is the brightest object, located to the right of the frame and seen as a bright star-like core surrounded by a hazy halo. A few of the other galaxies of the cluster are also visible, looking like flying saucers dancing around NGC 4874. But the really remarkable feature of this image is the point-like objects around NGC 4874, revealed on a closer look: almost all of them are clusters of stars that belong to the galaxy. Each of these globular star clusters contains many hundreds of thousands of stars.

NGC 488 Galaxy

 

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Region NGC 2264 (aka Sh2-273) includes the sparkling blue baubles of the Christmas Tree star cluster and the Cone Nebula.

NGC 2264 is an open cluster of stars embedded in a diffuse nebula. It is located in the constellation of Monoceros. The image also contains two famous nebulae. At the bottom center of the image is the Cone Nebula, and to the upper left is the Fox Fur Nebula. The bright star just above the center of the image is known as S Mon. The gentle arcs in orange and blue near the center of the image are Herbig Haro objects, jets of gas from protostars embedded in the nebula.

 

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UW astronomers find a rare supernova ‘impostor’ - SN 2010da - in a spiral galaxy NGC 300 which lies > 6 million ly away.

SN 2010da is 20-25 times the mass of our sun and has a companion (a neutron star).

The supernova impostor SN 2010da circled in green and the X-ray emission indicated by a white cross.
There was just this massive amount of X-rays coming from SN 2010da, which you should not see coming from a supernova impostor. The X-rays are likely produced when material from the impostor star is transferred to the neutron star companion. The X-rays represent the neutron star “turning on” for the first time after its formation.


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A young pre-main-sequence star HBC 1 surrounded by an envelope of dust. In this view, HBC 1 illuminates a wispy reflection nebula IRAS 00044+6521.

 

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Silver Dollar Galaxy: NGC 253

In this edge-on view from NASA's Galaxy Evolution Explorer, the wisps of blue represent relatively dustless areas of the galaxy that are actively forming stars. Areas of the galaxy with a soft golden glow indicate regions where the far-ultraviolet is heavily obscured by dust particles.

 

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The giant spiral galaxy NGC 253 (aka Silver Dollar galaxy) (shown in color) is accompanied by a newly discovered dwarf galaxy, NGC 253-dw2 (at upper left). The peculiar, elongated shape of the dwarf implies it is being torn apart by the gravity of the bigger galaxy – which in turn shows irregularities on its periphery that may be caused by the mutual interaction. They are located in the Southern constellation of Sculptor at a distance of 11 million ly from us, and are separated from each other by ~ 160 000 ly.

The dwarf has been trapped by its giant host and will not survive intact for much longer. The next time it plunges closer to its host, it could be shredded into oblivion. However, the host may suffer some damage too, if the dwarf is heavy enough. This looks like a case of galactic stealth attack. The dwarf galaxy has dived in from the depths of space and barraged the giant, while remaining undetected by virtue of its extreme faintness.

Close-up view of the dwarf galaxy NGC 253-dw2. The closely packed red dots show that it is composed of individual stars.

 

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The open cluster Trumpler 16. This cluster is embedded within the Carina Nebula. At the top of the image, a peculiar nebula with the shape of a "defiant" finger points towards WR25 and Tr16-244.

 

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Ground-based image of Herbig-Haro objects in the Orion Molecular Cloud Complex [a giant region of gas and dust undergoing active star formation]

Adam Block obtained this image of V1025 Tauri. V1025 Tauri is seen in the earliest stage of stellar evolution as it collapses to become a mature star. The nuclear fusion at the center of the star has begun, but does not yet have enough energy to blow away the dust clouds surrounding it.