Category Archives: Galaxies

Expelling A Black Hole

Think gravity waves are weak? Think again, wow almost hard to believe.

Credit: Hubblesite

from STSci:

Astronomers have uncovered a supermassive black hole that has been propelled out of the center of a distant galaxy by what could be the awesome power of gravitational waves.

Though there have been several other suspected, similarly booted black holes elsewhere, none has been confirmed so far. Astronomers think this object, detected by NASA’s Hubble Space Telescope, is a very strong case. Weighing more than 1 billion suns, the rogue black hole is the most massive black hole ever detected to have been kicked out of its central home.

Researchers estimate that it took the equivalent energy of 100 million supernovas exploding simultaneously to jettison the black hole. The most plausible explanation for this propulsive energy is that the monster object was given a kick by gravitational waves unleashed by the merger of two hefty black holes at the center of the host galaxy.
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NuStar Looks at Was 49

This is pretty amazing.  For scale the distance mentioned in the press release below of 26,000 light years  approximates the distance from out solar system to the center of our Milky Way.  See here.

A long way for solar system sure, but a galaxy?  Even a small one?  Amazing.

The press release:

A supermassive black hole inside a tiny galaxy is challenging scientists’ ideas about what happens when two galaxies become one.

Was 49 is the name of a system consisting of a large disk galaxy, referred to as Was 49a, merging with a much smaller “dwarf” galaxy called Was 49b. The dwarf galaxy rotates within the larger galaxy’s disk, about 26,000 light-years from its center. Thanks to NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) mission, scientists have discovered that the dwarf galaxy is so luminous in high-energy X-rays, it must host a supermassive black hole much larger and more powerful than expected.

“This is a completely unique system and runs contrary to what we understand of galaxy mergers,” said Nathan Secrest, lead author of the study and postdoctoral fellow at the U.S. Naval Research Laboratory in Washington.

Data from NuSTAR and the Sloan Digital Sky Survey suggest that the mass of the dwarf galaxy’s black hole is huge, compared to similarly sized galaxies, at more than 2 percent of the galaxy’s own mass.

“We didn’t think that dwarf galaxies hosted supermassive black holes this big,” Secrest said. “This black hole could be hundreds of times more massive than what we would expect for a galaxy of this size, depending on how the galaxy evolved in relation to other galaxies.”

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Frankenstein Galaxy


Galex data!

About the image<(Credits: NASA/JPL/Caltech/SDSS/NRAO/L. Hagen and M. Seibert):

About 250 million light-years away, there’s a neighborhood of our universe that astronomers had considered quiet and unremarkable. But now, scientists have uncovered an enormous, bizarre galaxy possibly formed from the parts of other galaxies.

A new study to be published in the Astrophysical Journal reveals the secret of UGC 1382, a galaxy that had originally been thought to be old, small and typical. Instead, scientists using data from NASA telescopes and other observatories have discovered that the galaxy is 10 times bigger than previously thought and, unlike most galaxies, its insides are younger than its outsides, almost as if it had been built using spare parts.

“This rare, ‘Frankenstein’ galaxy formed and is able to survive because it lies in a quiet little suburban neighborhood of the universe, where none of the hubbub of the more crowded parts can bother it,” said study co-author Mark Seibert of the Observatories of the Carnegie Institution for Science, Pasadena, California. “It is so delicate that a slight nudge from a neighbor would cause it to disintegrate.”

Seibert and Lea Hagen, a graduate student at Pennsylvania State University, University Park, came upon this galaxy by accident. They had been looking for stars forming in run-of-the-mill elliptical galaxies, which do not spin and are more three-dimensional and football-shaped than flat disks. Astronomers originally thought that UGC 1382 was one of those.

But while looking at images of galaxies in ultraviolet light through data from NASA’s Galaxy Evolution Explorer (GALEX), a behemoth began to emerge from the darkness.

“We saw spiral arms extending far outside this galaxy, which no one had noticed before, and which elliptical galaxies should not have,” said Hagen, who led the study. “That put us on an expedition to find out what this galaxy is and how it formed.”

Researchers then looked at data of the galaxy from other telescopes: the Sloan Digital Sky Survey, the Two Micron All-Sky Survey (2MASS), NASA’s Wide-field Infrared Survey Explorer (WISE), the National Radio Astronomy Observatory’s Very Large Array and Carnegie’s du Pont Telescope at Las Campanas Observatory. After GALEX revealed previously unseen structures to the astronomers, optical and infrared light observations from the other telescopes allowed the researchers to build a new model of this mysterious galaxy.

As it turns out, UGC 1382, at about 718,000 light-years across, is more than seven times wider than the Milky Way. It is also one of the three largest isolated disk galaxies ever discovered, according to the study. This galaxy is a rotating disk of low-density gas. Stars don’t form here very quickly because the gas is so spread out.

But the biggest surprise was how the relative ages of the galaxy’s components appear backwards. In most galaxies, the innermost portion forms first and contains the oldest stars. As the galaxy grows, its outer, newer regions have the youngest stars. Not so with UGC 1382. By combining observations from many different telescopes, astronomers were able to piece together the historical record of when stars formed in this galaxy — and the result was bizarre.

“The center of UGC 1382 is actually younger than the spiral disk surrounding it,” Seibert said. “It’s old on the outside and young on the inside. This is like finding a tree whose inner growth rings are younger than the outer rings.”

The unique galactic structure may have resulted from separate entities coming together, rather than a single entity that grew outward. In other words, two parts of the galaxy seem to have evolved independently before merging — each with its own history.

At first, there was likely a group of small galaxies dominated by gas and dark matter, which is an invisible substance that makes up about 27 percent of all matter and energy in the universe (our own matter is only 5 percent). Later, a lenticular galaxy, a rotating disk without spiral arms, would have formed nearby. At least 3 billion years ago, the smaller galaxies may have fallen into orbit around the lenticular galaxy, eventually settling into the wide disk seen today.

More galaxies like this may exist, but more research is needed to look for them.

“By understanding this galaxy, we can get clues to how galaxies form on a larger scale, and uncover more galactic neighborhood surprises,” Hagen said.

The GALEX mission, which ended in 2013 after more than a decade of scanning the skies in ultraviolet light, was led by scientists at Caltech in Pasadena, California. NASA’s Jet Propulsion Laboratory, also in Pasadena, managed the mission and built the science instrument. Data for the 2MASS and WISE missions are archived at the Infrared Processing and Analysis Center (IPAC) at Caltech. JPL is managed by Caltech for NASA.

Merging Galaxies


One day our Milky Way will be in the midst of a similar merger, ours with Andromeda.

The ESA description:
The subject of this NASA/ESA Hubble Space Telescope image is known as NGC 3597. It is the product of a collision between two good-sized galaxies, and is slowly evolving to become a giant elliptical galaxy. This type of galaxy has grown more and more common as the Universe has evolved, with initially small galaxies merging and progressively building up into larger galactic structures over time.

NGC 3597 is located approximately 150 million light-years away in the constellation of Crater (The Cup). Astronomers study NGC 3597 to learn more about how elliptical galaxies form — many ellipticals began their lives far earlier in the history of the Universe. Older ellipticals are nicknamed “red and dead” by astronomers because these bloated galaxies are not anymore producing new, bluer, stars in ages, and are thus packed full of old and redder stellar populations.

Before infirmity sets in, some freshly formed elliptical galaxies experience a final flush of youth, as is the case with NGC 3597. Galaxies smashing together pool their available gas and dust, triggering new rounds of star birth. Some of this material ends up in dense pockets initially called proto-globular clusters, dozens of which festoon NGC 3597. These pockets will go on to collapse and form fully-fledged globular clusters, large spheres that orbit the centres of galaxies like satellites, packed tightly full of millions of stars.

Image and caption: ESA/Hubble & NASA

IDCS 1426

A collaboration of three amazing telescopes: Chandra, Herschel and Spitzer.

10 BILLION light-years distant!

Astronomers have made the most detailed study yet of an extremely massive young galaxy cluster using three of NASA’s Great Observatories. This multi-wavelength image shows this galaxy cluster, called IDCS J1426.5+3508 (IDCS 1426 for short), in X-rays recorded by the Chandra X-ray Observatory in blue, visible light observed by the Hubble Space Telescope in green, and infrared light detected by the Spitzer Space Telescope in red.

This rare galaxy cluster, which is located 10 billion light-years from Earth, is almost as massive as 500 trillion suns. This object has important implications for understanding how such megastructures formed and evolved early in the universe. The light astronomers observed from IDCS 1426 began its journey to Earth when the universe was less than a third of its current age. It is the most massive galaxy cluster detected at such an early time.

First discovered by the Spitzer Space Telescope in 2012, IDCS 1426 was then observed using the Hubble Space Telescope and the Keck Observatory to determine its distance. Observations from the Combined Array for Millimeter-wave Astronomy indicated it was extremely massive. New data from the Chandra X-ray Observatory confirm the galaxy cluster’s mass and show that about 90 percent of this mass is in the form of dark matter — the mysterious substance that has so far been detected only through its gravitational pull on normal matter composed of atoms.

There is a region of bright X-ray emission (seen as blue-white) near the middle of the cluster, but not exactly at the center. The location of this “core” of gas suggests that the cluster may have had a collision or interaction with another massive system of galaxies relatively recently, perhaps within about the last 500 million years. This would cause the core to slosh around like wine in a moving glass and become offset, as it appears to be in the Chandra data. Such a merger would not be surprising, given that astronomers are observing IDCS 1426 when the universe was only 3.8 billion years old. Scientists think that, in order for such an enormous structure to form so rapidly, mergers with smaller clusters would likely play a role in the large cluster’s growth.

In addition, while still extremely hot, the bright core contains cooler gas than its surroundings. This is the most distant galaxy cluster where such a “cool core” of gas has been observed. Astronomers think these cool cores are important in understanding how quickly hot gas cools off in clusters, influencing the rate at which stars are born. This cooling rate could be slowed down by outbursts from a supermassive black hole in the center of the cluster. Apart from the cool core, the hot gas in the cluster is remarkably symmetrical and smooth. This is another piece of evidence that IDCS 1426 formed very rapidly in the early universe.

Astronomers note that, despite the high mass and rapid evolution of this cluster, its existence does not pose a threat to the standard model of cosmology.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.

NGC 5195


Some of the information coming out of the American Astronomical Society being held this week in Florida.

BTW: the Whirlpool is a very nice telescope target in the northern skies even for smaller scopes.  The galaxy is also known as M-51.  Get coordinates here at SEDS.

Here is the AAS release from NASA:

Astronomers have used NASA’s Chandra X-ray Observatory to discover one of the nearest supermassive black holes to Earth that is currently undergoing powerful outbursts, as described in our latest press release. This galactic burping was found in the Messier 51 galaxy, which is located about 26 million light years from Earth and contains a large spiral galaxy NGC 5194 (also known by its nickname of the “Whirlpool”), merging with a smaller companion galaxy NGC 5195.
 The main panel of this graphic shows M51 in visible light data from the Hubble Space Telescope (red, green, and blue). The box at the top of the image outlines the field of view by Chandra in the latest study, which focuses on the smaller component of M51, NGC 5195.  

The inset to the right shows the details of the Chandra data (blue) of this region. Researchers found a pair of arcs in X-ray emission close to the center of the galaxy, which they interpret as two outbursts from the galaxy’s supermassive black hole (see annotated image for additional information). The authors estimate that it took about one to three million years for the inner arc to reach its current position, and three to six million years for the outer arc. 

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Colliding Galaxies

Hubble captures two galaxies colliding.  Image: Credit: NASA and ESA Acknowledgment: A. Gal-Yam (Weizmann Institute of Science)
Hubble captures two galaxies colliding. Image: Credit: NASA and ESA Acknowledgment: A. Gal-Yam (Weizmann Institute of Science)

This is an amazing image. Hubblesite has a “zoomable” version of this and I’ve been trying to count the smaller more distant galaxies – I’m at 22 other than the two subjects of the image.

This NASA Hubble Space Telescope photo of NGC 7714 presents an especially striking view of the galaxy’s smoke-ring-like structure. The golden loop is made of sun-like stars that have been pulled deep into space, far from the galaxy’s center. The galaxy is located approximately 100 million light-years from Earth in the direction of the constellation Pisces.
The universe is full of such galaxies that are gravitationally stretched and pulled and otherwise distorted in gravitational tug-o’-wars with bypassing galaxies.

The companion galaxy doing the “taffy pulling” in this case, NGC 7715, lies just out of the field of view in this image. A very faint bridge of stars extends to the unseen companion. The close encounter has compressed interstellar gas to trigger bursts of star formation seen in bright blue arcs extending around NGC 7714’s center.

The gravitational disruption of NGC 7714 began between 100 million and 200 million years ago, at the epoch when dinosaurs ruled the Earth.

The image was taken with the Wide Field Camera 3 and the Advanced Camera for Surveys in October 2011.
The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

A Lenticular Galaxy

The lenticular galaxy NGC  6861 Credit: ESA/Hubble & NASA; acknowledgement: J. Barrington
The lenticular galaxy NGC 6861 Credit: ESA/Hubble & NASA; acknowledgement: J. Barrington

Hubble gives us this spectacular view of NGC 6861. I always thought this was an elliptical galaxy. Not so, it’s a hybrid of sorts between an elliptical and a spiral called a lenticular.

Not viewable here at 45 deg North, it is a southern object.  Too bad, it’s a beauty.  I believe this galaxy is in the order of 31 Mpc distant or a little over 101 million light-years and still it is a magnitude 11 to 12.  Distances are very tough to determine so there is some room for error.

Note: My computer is failing. Should I disappear for a short time you will know why. I think I can keep it going long enough to get a replacement – still one never knows.

From ESA via the NASA site:

The subject of this image is NGC 6861, a galaxy discovered in 1826 by the Scottish astronomer James Dunlop. Almost two centuries later we now know that NGC 6861 is the second brightest member of a group of at least a dozen galaxies called the Telescopium Group — otherwise known as the NGC 6868 Group — in the small constellation of Telescopium (The Telescope).

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DDO 68 An Odd Little Galaxy

A dwarf galaxy DDO68 might not be as young as it seems.  Copyright: NASA, ESA. Acknowledgement: A. Aloisi (Space Telescope Science Institute)
A dwarf galaxy DDO68 might not be as young as it seems. Copyright: NASA, ESA. Acknowledgement: A. Aloisi (Space Telescope Science Institute)

From the ESA’s Hubble page:

Astronomers have studied galactic evolution for decades, gradually improving our knowledge of how galaxies have changed over cosmic history. The NASA/ESA Hubble Space Telescope has played a big part in this, allowing astronomers to see further into the distance, and hence further back in time, than any telescope before it – capturing light that has taken billions of years to reach us.

Looking further into the very distant past to observe younger and younger galaxies is very valuable, but it is not without its problems for astronomers. All newly-born galaxies lie very far away from us and appear very small and faint in the images. On the contrary, all the galaxies near to us appear to be old ones.

DDO 68, captured here by the NASA/ESA Hubble Space Telescope, was one of the best candidates so far discovered for a newly-formed galaxy in our cosmic neighbourhood. The galaxy lies around 39 million light-years away from us; although this distance may seem huge, it is in fact roughly 50 times closer than the usual distances to such galaxies, which are on the order of several billions of light years.

Read the rest at ESA’s Hubble page.

A side note: I thought this dwarf galaxy was actually two galaxies in the process of merging, apparently not?