chandra x ray observatory

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COSMIC ‘WINTER’ WONDERLAND

Although there are no seasons in space, this cosmic vista invokes thoughts of a frosty winter landscape. It is, in fact, a region called NGC 6357 where radiation from hot, young stars is energizing the cooler gas in the cloud that surrounds them.

This composite image contains X-ray data from NASA’s Chandra X-ray Observatory and the ROSAT telescope (purple), infrared data from NASA’s Spitzer Space Telescope (orange), and optical data from the SuperCosmos Sky Survey (blue) made by the United Kingdom Infrared Telescope.

Located in our galaxy about 5,500 light-years from Earth, NGC 6357 is actually a “cluster of clusters,” containing at least three clusters of young stars, including many hot, massive, luminous stars. The X-rays from Chandra and ROSAT reveal hundreds of point sources, which are the young stars in NGC 6357, as well as diffuse X-ray emission from hot gas. There are bubbles, or cavities, that have been created by radiation and material blowing away from the surfaces of massive stars, plus supernova explosions.

Astronomers call NGC 6357 and other objects like it “HII” (pronounced “H-two”) regions. An HII region is created when the radiation from hot, young stars strips away the electrons from neutral hydrogen atoms in the surrounding gas to form clouds of ionized hydrogen, which is denoted scientifically as “HII.”

Researchers use Chandra to study NGC 6357 and similar objects because young stars are bright in X-rays. Also, X-rays can penetrate the shrouds of gas and dust surrounding these infant stars, allowing astronomers to see details of star birth that would be otherwise missed.


TOP IMAGE…. NGC 6357 COMPOSITE

CENTRE IMAGE…. NGC 6357 X-RAY

LOWER IMAGE…. NGC 6357 OPTICAL

BOTTOM IMAGE…. NGC 6357 INFRARED

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Eileen Collins blazed a trail for women engineers to follow

On July 23, 1999, on the eve of the new millennium, Eileen Collins broke through a major glass ceiling on her way to breaking free of Earth’s atmosphere. Having already made history as the first female Space Shuttle pilot, in 1995, Col. Collins now led STS-93 Columbia  and its mission to deploy the Chandra X-Ray Observatory as the first female shuttle commander in the history of NASA.

Despite Collins’s inspirational example, women remain significantly underrepresented across STEM fields. Only one other woman, Pamela Melroy, has been a Shuttle Commander, and although women account for more than 50% of the U.S. population, they make up less than 25% of STEM workers.

Having a role model like Collins and a supportive network to encourage women to enter and stay in STEM careers is critical to increasing gender diversity across STEM industries. Here are a few badass women who are following Collins’s example.

In collaboration with USAF

Astronomers have discovered what happens when the eruption from a supermassive black hole is swept up by the collision and merger of two galaxy clusters. This composite image contains X-rays from Chandra (blue), radio emission from the GMRT (red), and optical data from Subaru (red, green, and blue) of the colliding galaxy clusters called Abell 3411 and Abell 3412. These and other telescopes were used to analyze how the combination of these two powerful phenomena can create an extraordinary cosmic particle accelerator.

Image credit: X-ray: NASA/CXC/SAO/R. van Weeren et al; Optical: NAOJ/Subaru; Radio: NCRA/TIFR/GMRT/ Chandra X-ray Observatory

Black hole feeding frenzy breaks records

A giant black hole ripped apart a nearby star and then continued to feed off its remains for close to a decade, according to research led by the University of New Hampshire. This black hole meal is more than 10 times longer than any other previous episode of a star’s death.

“We have witnessed a star’s spectacular and prolonged demise,” said Dacheng Lin, a research scientist at UNH’s Space Science Center and the study’s lead author. “Dozens of these so-called tidal disruption events have been detected since the 1990s, but none that remained bright for nearly as long as this one.”

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boom-kaka-laka  asked:

Hey :) I don't want to be annoying or anything but I was wondering if you could recommend some books or websites were I could learn more about space.. I have huge interest in it but I don't really know much about anything from the astro field >_<

Since space always has a bunch of crazy shit going on in it, I’ll just take a bunch of random bookmarked links I have and throw them at you!

Books:Videos:Space Image Galleries: Cool Online Programs:Random Articles:

A new star, likely the brightest supernova in recorded human history, lit up planet Earth’s sky in the year 1006 AD. The expanding debris cloud from the stellar explosion, found in the southerly constellation of Lupus, still puts on a cosmic light show across the electromagnetic spectrum. In fact, this composite view includes X-ray data in blue from the Chandra Observatory, optical data in yellowish hues, and radio image data in red. Now known as the SN 1006 supernova remnant, the debris cloud appears to be about 60 light-years across and is understood to represent the remains of a white dwarf star. Part of a binary star system, the compact white dwarf gradually captured material from its companion star. The buildup in mass finally triggered a thermonuclear explosion that destroyed the dwarf star. Because the distance to the supernova remnant is about 7,000 light-years, that explosion actually happened 7,000 years before the light reached Earth in 1006. Shockwaves in the remnant accelerate particles to extreme energies and are thought to be a source of the mysterious cosmic rays.

Credit: NASA, ESA, Zolt Levay (STScl)

Time And Space

Infrared, X-ray & Optical Images of Centaurus A

Centaurus A is the fifth brightest galaxy in the sky – making it an ideal target for amateur astronomers – and is famous for the dust lane across its middle and a giant jet blasting away from the supermassive black hole at its center.  Cen A is an active galaxy about 12 million light years from Earth.

Credit: X-ray: NASA/CXC/SAO; Optical: Rolf Olsen; Infrared: NASA/JPL-Caltech

BLACK HOLE MEAL SETS RECORD FOR DURATION AND SIZE

A giant black hole ripped apart a star and then gorged on its remains for about a decade, according to astronomers. This is more than 10 times longer than any observed episode of a star’s death by black hole.

Researchers made this discovery using data from NASA’s Chandra X-ray Observatory and Swift satellite as well as ESA’s XMM-Newton.

The trio of orbiting X-ray telescopes found evidence for a “tidal disruption event” (TDE), wherein the tidal forces due to the intense gravity from a black hole can destroy an object – such as a star – that wanders too close. During a TDE, some of the stellar debris is flung outward at high speeds, while the rest falls toward the black hole. As it travels inwards to be ingested by the black hole, the material becomes heats up to millions of degrees and generates a distinct X-ray flare.

“We have witnessed a star’s spectacular and prolonged demise,” said Dacheng Lin from the University of New Hampshire in Durham, New Hampshire, who led the study. “Dozens of tidal disruption events have been detected since the 1990s, but none that remained bright for nearly as long as this one.”

The extraordinary long bright phase of this event spanning over 10 years means that among observed TDEs this was either the most massive star ever to be completely torn apart during one of these events, or the first where a smaller star was completely torn apart.

The X-ray source containing this force-fed black hole, known by its abbreviated name of XJ1500+0154, is located in a small galaxy about 1.8 billion light-years from Earth.

The source was not detected in a Chandra observation on April 2, 2005, but was detected in an XMM-Newton observation on July 23, 2005, and reached peak brightness in a Chandra observation on June 5, 2008. These observations show that the source became at least 100 times brighter in X-rays. Since then, Chandra, Swift, and XMM-Newton have observed it multiple times.

The sharp X-ray vision of Chandra data shows that XJ1500+0154 is located at the center of its host galaxy, the expected location for a supermassive black hole.

The X-ray data also indicate that radiation from material surrounding this black hole has consistently surpassed the so-called Eddington limit, defined by a balance between the outward pressure of radiation from the hot gas and the inward pull of the gravity of the black hole.

“For most of the time we’ve been looking at this object, it has been growing rapidly,” said co-author James Guillochon of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. “This tells us something unusual – like a star twice as heavy as our Sun – is being fed into the black hole.”

The conclusion that supermassive black holes can grow, from TDEs and perhaps other means, at rates above those corresponding to the Eddington limit has important implications. Such rapid growth may help explain how supermassive black holes were able to reach masses about a billion times higher than the Sun when the universe was only about a billion years old.

“This event shows that black holes really can grow at extraordinarily high rates,” said co-author Stefanie Komossa of QianNan Normal University for Nationalities in Duyun City, China. “This may help understand how precocious black holes came to be.”

Based on the modeling by the researchers the black hole’s feeding supply should be significantly reduced in the next decade. This would result in XJ1500+0154 fading in X-ray brightness over the next several years.

What is a black hole?

When a star runs out of nuclear fuel, it will collapse. If the core, or central region, of the star has a mass that is greater than three Suns, no known nuclear forces can prevent the core from forming a deep gravitational warp in space called a black hole.

A black hole does not have a surface in the usual sense of the word. There is simply a region, or boundary, in space around a black hole beyond which we cannot see.

This boundary is called the event horizon. Anything that passes beyond the event horizon is doomed to be crushed as it descends ever deeper into the gravitational well of the black hole. No visible light, nor X-rays, nor any other form of electromagnetic radiation, nor any particle, no matter how energetic, can escape. The radius of the event horizon (proportional to the mass) is very small, only 30 kilometers for a non-spinning black hole with the mass of 10 Suns.

Can astronomers see a black hole? Not directly. The only way to find one is to use circumstantial evidence. Observations must imply that a sufficiently large amount of matter is compressed into a sufficiently small region of space so that no other explanation is possible. For stellar black holes, this means observing the orbital acceleration of a star as it orbits its unseen companion in a double or binary star system.

Searching for black holes is tricky business. One way to locate them has been to study X-ray binary systems. These systems consist of a visible star in close orbit around an invisible companion star which may be a neutron star or black hole. The companion star pulls gas away from the visible star.

As this gas forms a flattened disk, it swirls toward the companion. Friction caused by collisions between the particles in the gas heats them to extreme temperatures and they produce X-rays that flicker or vary in intensity within a second.

Many bright X-ray binary sources have been discovered in our galaxy and nearby galaxies. In about ten of these systems, the rapid orbital velocity of the visible star indicates that the unseen companion is a black hole. The X-rays in these objects are produced by particles very close to the event horizon. In less than a second after they give off their X-rays, they disappear beyond the event horizon.

However, not all the matter in the disk around a black hole is doomed to fall into the black hole. In many black hole systems, some of the gas escapes as a hot wind that is blown away from the disk at high speeds. Even more dramatic are the high-energy jets that radio and X-ray observations show exploding away from some stellar black holes. These jets can move at nearly the speed of light in tight beams and travel several light years before slowing down and fading away.

Do black holes grow when matter falls into them? Yes, the mass of the black hole increases by an amount equal to the amount of mass it captures. The radius of the event horizon also increases by about 3 kilometers for every solar mass that it swallows. A black hole in the center of a galaxy, where stars are densely packed, may grow to the mass of a billion Suns and become what is known as a supermassive black hole.

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The above images are spectacular representations of what Chandra X-Ray Telescope has brought to the astronomy table. The earth’s atmosphere filters out a great majority of x-rays, therefore, by having a telescope in orbit outside of the atmosphere, it gives astronomers a new perspective on the makeup of various celestial bodies. As seen in these images, high energy particles often emit high levels of x-rays which are typically invisible to us if we simply take a picture in the visible spectrum. Having an x-ray observatory like Chandra opens a brand new (beautiful) window to the universe.

(NASA)  Young Magnetar Likely the Slowest Pulsar Ever Detected

Image credit: X-ray: NASA/CXC/University of Amsterdam/N.Rea et al; Optical: DSS

Using NASA’s Chandra X-ray Observatory and other X-ray observatories, astronomers have found evidence for what is likely one of the most extreme pulsars or rotating neutron stars, ever detected. The source exhibits properties of a highly magnetized neutron star or magnetar, yet its deduced spin period is thousands of times longer than any pulsar ever observed.

For decades, astronomers have known there is a dense, compact source at the center of RCW 103, the remains of a supernova explosion located about 9,000 light years from Earth.  This composite image shows RCW 103 and its central source, known officially as 1E 161348-5055 (1E 1613, for short), in three bands of X-ray light detected by Chandra. In this image, the lowest energy X-rays from Chandra are red, the medium band is green, and the highest-energy X-rays are blue. The bright blue X-ray source in the middle of RCW 103 is 1E 1613. The X-ray data have been combined with an optical image from the Digitized Sky Survey.

Observers had previously agreed that 1E 1613 is a neutron star, an extremely dense star created by the supernova that produced RCW 103. However, the regular variation in the X-ray brightness of the source, with a period of about six and a half hours, presented a puzzle.  All proposed models had problems explaining this slow periodicity, but the main ideas were of either a spinning neutron star that is rotating extremely slowly because of an unexplained slow-down mechanism or a faster-spinning neutron star that is in orbit with a normal star in a binary system.

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What Is Dark Matter?

There is as yet no answer to this question, but it is becoming increasingly clear what it is not. Detailed observations of the cosmic microwave background with the WMAP satellite show that the dark matter cannot be in the form of normal, baryonic matter, that is, protons and neutrons that compose stars, planets, and interstellar matter. That rules out hot gas, cold gas, brown dwarfs, red dwarfs, white dwarfs, neutron stars and black holes.

Black holes would seem to be the ideal dark matter candidate, and they are indeed very dark. However stellar mass black holes are produced by the collapse of massive stars which are much scarcer than normal stars, which contain at most one-fifth of the mass of dark matter. Also, the processes that would produce enough black holes to explain the dark matter would release a lot of energy and heavy elements; there is no evidence of such a release.

The non-baryonic candidates can be grouped into three broad categories: hot, warm and cold. Hot dark matter refers to particles, such as the known types of neutrinos, which are moving at near the speed of light when the clumps that would form galaxies and clusters of galaxies first began to grow. Cold dark matter refers to particles that were moving slowly when the pre-galactic clumps began to form, and warm dark matter refers to particles with speeds intermediate between hot and cold dark matter.

This classification has observational consequences for the size of clumps that can collapse in the expanding universe. Hot dark matter particles are moving so rapidly that clumps with the mass of a galaxy will quickly disperse. Only clouds with the mass of thousands of galaxies, that is, the size of galaxy clusters, can form. Individual galaxies would form later as the large cluster-sized clouds fragmented, in a top-down process.

In contrast, cold dark matter can form into clumps of galaxy-sized mass or less. Galaxies would form first, and clusters would form as galaxies merge into groups, and groups into clusters in a bottom-up process.

The observations with Chandra show many examples of clusters being constructed by the merger of groups and sub-clusters of galaxies. This and other lines of evidence that galaxies are older than groups and clusters of galaxies strongly support the cold dark matter alternative. The leading candidates for cold dark matter are particles called WIMPs, for Weakly Interacting Massive Particles. WIMPs are not predicted by the so-called Standard Model for elementary particles, but attempts to construct a unified theory of all elementary particles suggest that WIMPs might have been produced in great numbers when the universe was a fraction of a second old.

A typical WIMP is predicted to be at least 100 times as massive as a hydrogen atom. Possible creatures in the zoo of hypothetical WIMPs are neutralinos, gravitinos, and axinos. Other possibilities that have been discussed include sterile neutrinos and Kaluza-Klein excitations related to extra dimensions in the universe.