Category Archives: Space Telescope

Hubble Update to NGC 6240


Here is an updated Hubble image of the galactic merger NGC 6240 (image description below) from an image in 2008. The image was taken with the Wide Field Camera 3 and Advanced Camera for Surveys which gives us a more detailed look at the center of the galaxies than in 2008. Click the image above to see the difference.

When I say galactic merger I don’t want to imply this merger is complete – far from it. What isn’t seen here are two black holes at the center of the merger only 3000 light-years apart and that is close enough for their fate to be set. The two black holes are feeling their mutual gravitational attraction and are slowly spiraling towards each other and will eventually merge into a single black hole.

We do have X-ray evidence of the two black holes in this image from the Chandra X-ray Observatory taken in 2002.

NGC 6240 is located 400 million light-years away in the constellation Ophiuchus, that is so far away, who knows perhaps the merger has already taken place, the cosmic look back time in action.

A side note: You would think there would be stars colliding in such mergers, but this is not the case. The distances between stars is so large such collisions are unlikely at least in any widespread way.

From Hubble (and you can get desktop versions of the image at the link):
Not all galaxies are neatly shaped, as this new NASA/ESA Hubble Space Telescope image of NGC 6240 clearly demonstrates. Hubble previously released an image of this galaxy back in 2008, but the knotted region, shown here in a pinky-red hue at the centre of the galaxies, was only revealed in these new observations from Hubble’s Wide Field Camera 3 and Advanced Camera for Surveys.

NGC 6240 lies 400 million light-years away in the constellation of Ophiuchus (The Serpent Holder). This galaxy has an elongated shape with branching wisps, loops and tails. This mess of gas, dust and stars bears more than a passing resemblance to a butterfly and, though perhaps less conventionally beautiful, a lobster.

This bizarrely-shaped galaxy did not begin its life looking like this; its distorted appearance is a result of a galactic merger that occurred when two galaxies drifted too close to one another. This merger sparked bursts of new star formation and triggered many hot young stars to explode as supernovae. A new supernova was discovered in this galaxy in 2013, named SN 2013dc. It is not visible in this image, but its location is indicated here.

At the centre of NGC 6240 an even more interesting phenomenon is taking place. When the two galaxies came together, their central black holes did so too. There are two supermassive black holes within this jumble, spiralling closer and closer to one another. They are currently only some 3000 light-years apart, incredibly close given that the galaxy itself spans 300 000 light-years. This proximity secures their fate as they are now too close to escape each other and will soon form a single immense black hole.

25 Years of Hubble

NASA Unveils Celestial Fireworks as Official Hubble 25th Anniversary Image

Happy Anniversary Hubble! Hubble was launched 25 years ago today on 24 April 1990 aboard the Shuttle Discovery on mission STS-31.

The Hubble was deployed on 25 April 1990 and immediately a problem with the optics was noticed and it would take a couple of years to get a correction in place. Once the corrective optics, kind of like “eye-glasses” for the telescope were flown up in December 1993 aboard the Shuttle Endeavour along with a few other upgrades and the repairs were made, the images were stunning.

Hubble has be serviced a few times since and continues to advance our knowledge and will for many more years with any luck at all.

About the image from Hubblesite:

NASA and ESA are celebrating the Hubble Space Telescope’s silver anniversary of 25 years in space by unveiling some of nature’s own fireworks — a giant cluster of about 3,000 stars called Westerlund 2. The cluster resides inside a vibrant stellar breeding ground known as Gum 29, located 20,000 light-years away in the constellation Carina. The comparatively young, 2-million-year-old star cluster contains some of our galaxy’s hottest, brightest, and most massive stars. The largest stars are unleashing a torrent of ultraviolet light and hurricane-force winds that etch away the enveloping hydrogen gas cloud. This creates a fantasy celestial landscape of pillars, ridges, and valleys.

Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA), A. Nota (ESA/STScI), and the Westerlund 2 Science Team

Hubble and NGC 2865


Yes the galaxy NGC 2865 is a bit different, an elliptical with lots of young stars is not what we would first think of in an elliptical galaxy. I’ll let ESA/NASA explain, but be sure to click the image and get the larger version. The number of galaxies much further away is amazing and one of the hallmarks of Hubble images.

This NASA/ESA Hubble Space Telescope image shows an elliptical galaxy called NGC 2865. It lies just over 100 million light-years away from us in the constellation of Hydra — The Sea Serpent — and was discovered in 1835 by astronomer John Herschel.

Elliptical galaxies are usually filled with old, dying stars. NGC 2865, however, is relatively youthful and dynamic, with a rapidly rotating disk full of young stars and metal-rich gas. For an elliptical galaxy it contains an unusually high number of young stars — suggesting that a galaxy-wide starburst took place about one billion years ago.

The starburst itself was induced by a merger between a spiral galaxy, similar to our galaxy, the Milky Way, and an elliptical galaxy some three times more massive — the progenitor galaxy of NGC 2865. The new gas from the spiral galaxy revitalized the dying population of old stars in the elliptical galaxy, and several new generations of stars were born.

The faint halo surrounding the galaxy, visible in this image, is also a result of this merger. It consists of cold gas that was ripped away from the spiral galaxy during the merging process. The gas now forms an almost closed shell around its host galaxy.

European Space Agency
Credit: ESA/Hubble & NASA
Acknowledgement: Judy Schmidt

GK Persied

A colloboration of Chandra, Hubble, and VLA showing GK Persei.  Image Credit: NASA/CXC/RIKEN/D.Takei et al
A colloboration of Chandra, Hubble, and VLA showing GK Persei. Image Credit: NASA/CXC/RIKEN/D.Takei et al

Astronomers studied the famous 1901 nova with the Chandra X-ray Observatory (blue color) in February 2000 and again November 2013 with additional data from Hubble (yellow color), and the Very Large Array (pink). The 13-span provided some interesting data and new questions.

First a little backgound. In 1901 GK Persei suddenly became one of the brightest objects in the sky. It was a classic nova, one where material was collected by a white dwarf star from a companion star builds up to a point when nuclear fusion reactions can occur and the outer layers of the white dwarf are blown away by the explosion. The results of the explosion can be seen for weeks and sometimes years especially if we use world class observatories. Think of these explosions as mini-supernovae. Supernova are responsible for making the heavy elements that make planets, moons and even us. Studying these smaller explosions gives us clues to dynamics of larger one.

The debris from the nova has expanded of a speed around 1,126,510 kmh / 700,000 mph. That means in the 13 years between observations the blast wave moved over 144 billion km / 90 billion miles.

The luminosity of the Persei remnant has decreased by about 40 percent, that’s pretty reasonable but the temperature of the explosion has remained constant at about a million degrees Celsius. The temperature should have dropped, suggesting the blast wave is expanding into a region of lower density.

The optical data show clumps of material ejected in the explosion as expected, there is a point souce in the lower left of the image, the nature of which is unknown.

A more indepth explanation of the image can be found here.

Hubble’s View of NGC 4424

Hubble's image of NGC 4424 in the Virgo Cluster. Copyright ESA/Hubble & NASA
Hubble’s image of NGC 4424 in the Virgo Cluster. Copyright ESA/Hubble & NASA

The Virgo Cluster of galaxies, home to NGC 4424 is about 15.6 million parsecs (54 million light-years) away.

ESA’s caption:

The galaxy pictured here is NGC 4424, located in the constellation of Virgo. It is not visible with the naked eye but has been captured here with the NASA/ESA Hubble Space Telescope.

Although it may not be obvious from this image, NGC 4424 is in fact a spiral galaxy. In this image it is seen more or less edge on, but from above you would be able to see the arms of the galaxy wrapping around its centre to give the characteristic spiral form .

In 2012 astronomers observed a supernova in NGC 4424 — a violent explosion marking the end of a star’s life. During a supernova explosion, a single star can often outshine an entire galaxy. However, the supernova in NGC 4424, dubbed SN 2012cg, cannot be seen here as the image was taken ten years prior to the explosion. Along the central region of the galaxy, clouds of dust block the light from distant stars and create dark patches.

To the left of NGC 4424 there are two bright objects in the frame. The brightest is another, smaller galaxy known as LEDA 213994 and the object closer to NGC 4424 is an anonymous star in our Milky Way.

Hubble Puts On a Happy Face

Hubble shows that happiness is a gravitational lens. Image Credit: NASA/ESA
Hubble shows that happiness is a gravitational lens. Image Credit: NASA/ESA

Hubble sees a happy face created by a beautiful gravitation lens. I saw this at NASA’s Image of the Day yesterday. Oddly enough I was just thinking about faces we precieve like the famous Face on Mars and now there is the face on Ceres. The face on Ceres will be short lived as Dawn will be there shortly, just as well the Ceres face looks scary. :)

The caption from the NASA Image of the Day site (credit: ESA):

In the center of this image, taken with the NASA/ESA Hubble Space Telescope, is the galaxy cluster SDSS J1038+4849 — and it seems to be smiling.

You can make out its two orange eyes and white button nose. In the case of this “happy face”, the two eyes are very bright galaxies and the misleading smile lines are actually arcs caused by an effect known as strong gravitational lensing.
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Eta Carinae at Periastron

Periastron observations from NASA’s Rossi X-ray Timing Explorer, the X-Ray Telescope aboard NASA’s Swift, the Hubble Space Telescope’s STIS instrument, were put together produce models and computer simulations to determine how the two stars in the nebula to interact.


Eagle Nebula in 2014

The Pillar of Creation imaged by Hubble in 2014.  Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)
The Pillar of Creation imaged by Hubble in 2014. Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

Wow! Look at that! Click the image for the larger version and take it in.

You can see the zoomable version at Hubblesite.

From Hubblesite:

NASA’s Hubble Space Telescope has revisited the famous Pillars of Creation, revealing a sharper and wider view of the structures in this visible-light image.

Astronomers combined several Hubble exposures to assemble the wider view. The towering pillars are about 5 light-years tall. The dark, finger-like feature at bottom right may be a smaller version of the giant pillars. The new image was taken with Hubble’s versatile and sharp-eyed Wide Field Camera 3.

The pillars are bathed in the blistering ultraviolet light from a grouping of young, massive stars located off the top of the image. Streamers of gas can be seen bleeding off the pillars as the intense radiation heats and evaporates it into space. Denser regions of the pillars are shadowing material beneath them from the powerful radiation. Stars are being born deep inside the pillars, which are made of cold hydrogen gas laced with dust. The pillars are part of a small region of the Eagle Nebula, a vast star-forming region 6,500 light-years from Earth.

The colors in the image highlight emission from several chemical elements. Oxygen emission is blue, sulfur is orange, and hydrogen and nitrogen are green.