Posted on by Tammy Plotner

Looking Into The Eye Of A Monster – Active Galaxy Markarian 509

Active galaxy Markarian 509 as seen by the Hubble Space Telescope's WFPC2. Credits: NASA, ESA, J. Kriss (STScI) and J. de Plaa (SRON)

[/caption]

“The world is a vampire, sent to drain… Secret destroyers, hold you up to the flames…” Ah, yes. It’s the biggest vampire of all – the supermassive black hole. In this instance, it’s not any average, garden-variety black hole, but one that’s 300 million times the mass of the Sun and growing. Bullet with butterfly wings? No. This is more a case of butterfly wings with bullets.

An international team of astronomers using five different telescopes set their sites on 460 million light-year distant Markarian 509 to check out the action surrounding its huge black hole. The imaging team included ESA’s XMM-Newton, Integral, NASA/ESA Hubble Space Telescope, NASA’s Chandra and Swift satellites, and the ground-based telescopes WHT and PARITEL. For a hundred days they monitored Markarian 509. Why? Because it is known to have brightness variations which could mean turbulent inflow. In turn, the inner radiation then drives an outflow of gas – faster than a speeding bullet.

“XMM-Newton really led these observations because it has such a wide X-ray coverage, as well as an optical monitoring camera,” says Jelle Kaastra, SRON Netherlands Institute for Space Research, who coordinated an international team of 26 astronomers from 21 institutes on four continents to make these observations.

And the vampire reared its ugly head. Instead of the previously documented 25% changes, it jumped to 60%. The hot corona surrounding the black hole was spattering out cold gas “bullets” at speeds in excess of one million miles per hour. These projectiles are torn away from the dusty torus, but the real surprise is that they are coming from an area just 15 light years away from the center. This is a lot further than most astronomers speculate could happen.

“There has been a debate in astronomy for some time about the origin of the outflowing gas,” says Kaastra.

But there’s more than just bullets here. These new observations at multiple wavelengths are showing the coolest gas in the line of sight toward Markarian 509 has 14 different velocity components – all from different locations at the galaxy’s heart. What’s more, there’s indications the black hole accretion disc may have a shield of gas harboring temperatures ranging in the millions of degrees – the motivating force behind x-rays and gamma rays.

An artist's impression of the central engine of an active galaxy. A black hole is surrounded by matter waiting to fall in. Fearsome radiation from near the black hole drives an outflow of gas. Credits: NASA and M. Weiss (Chandra X-ray Center)

“The only way to explain this is by having gas hotter than that in the disc, a so-called ‘corona’, hovering above the disc,” Jelle Kaastra says. “This corona absorbs and reprocesses the ultraviolet light from the disc, energising it and converting it into X-ray light. It must have a temperature of a few million degrees. Using five space telescopes, which enabled us to observe the area in unprecedented detail, we actually discovered a very hot ‘corona’ of gas hovering above the disc. This discovery allows us to make sense of some of the observations of active galaxies that have been hard to explain so far.”

To make things even more entertaining, the study has also found the signature of interstellar gas which may have been the result of a one-time galaxy collision. Although the evidence may be hundreds of thousands of light years away from Mrk 509, it may have initially triggered this activity.

“The results underline how important long-term observations and monitoring campaigns are to gain a deeper understanding of variable astrophysical objects. XMM-Newton made all the necessary organisational changes to enable such observations, and now the effort is paying off,” says Norbert Schartel, ESA XMM-Newton Project Scientist.

Ah, Markarian 509… “Despite all my rage… I am still just a rat in cage.”

Original Story Source: ESA News. For Further Reading: Multiwavelength Campaign on Mrk 509 VI. HST/COS Observations of the Far-ultraviolet Spectrum.

Posted on by Tammy Plotner

Stellar X-Rays Strip Planet To Bare Bones

Credit: X-ray: NASA/CXC/Univ of Hamburg/S.Schröter et al; Optical: NASA/NSF/IPAC-Caltech/UMass/2MASS, UNC/CTIO/PROMPT; Illustration: NASA/CXC/M.Weiss

[/caption]

Some 880 light years away, a star named CoRoT-2a is busy decimating one of its planets – CoRoT-2b. Orbiting the parent star at a distance of over two million miles is dangerous business in this cosmic neighborhood. While the intrepid exoplanet might be about a thousand times the size of Earth right now, it’s getting about five million tons of matter stripped away from it every second. Thanks to new data from NASA’s Chandra X-ray Observatory and the European Southern Observatory’s Very Large Telescope, we’re able to take a closer look at this high-energy process for an even better understanding of how planets may – or may not – survive the process of forming a solar system.

“This planet is being absolutely fried by its star,” said Sebastian Schroeter of the University of Hamburg in Germany. “What may be even stranger is that this planet may be affecting the behavior of the star that is blasting it.”

Discovered by the French Space Agency’s Convection, Rotation and planetary Transits (CoRoT) satellite in 2008, this hot system is estimated to be between about 100 million and 300 million years old. The active parent star is assumed to be completely formed, yet its high magnetic activity is producing a bright x-ray signature comparable to that of a younger star. What could be causing the deviation that racks CoRoT-2b with a hundred thousand times more radiation than we receive from Sol?

“Because this planet is so close to the star, it may be speeding up the star’s rotation and that could be keeping its magnetic fields active,” said co-author Stefan Czesla, also from the University of Hamburg. “If it wasn’t for the planet, this star might have left behind the volatility of its youth millions of years ago.”

However, CoRoT-2a might not be alone. There’s a possibility that it’s a binary system with the companion positioned at roughly a thousand AU. If so, why can’t the x-ray instruments detect it? The answer is… it is not feeding on a planet to keep it active. CoRoT-2b’s huge size and proximity make for an intriguing combination. For as long as it lasts…

“We’re not exactly sure of all the effects this type of heavy X-ray storm would have on a planet, but it could be responsible for the bloating we see in CoRoT-2b,” said Schroeter. “We are just beginning to learn about what happens to exoplanets in these extreme environments.”

Original Story Source: Chandra News. For further reading: The corona and companion of CoRoT-2a. Insights from X-rays and optical spectroscopy.

Posted on by Tammy Plotner

Galaxy Bets On A Pair Of Black Holes

How X-rays Work
This main image is a composite of X-rays from Chandra (blue) and optical data from the Hubble Space Telescope (gold) of the spiral galaxy NGC 3393. Meanwhile, the inset box shows the central region of NGC 3993 as observed just by Chandra.

[/caption]

About 160 million light years away in the constellation of Hydra, spiral galaxy NGC 3393 has been keeping a billion year old secret. It might have a poker face, but it has a pair of black holes up its sleeve…

Using information obtained through NASA’s Chandra X-ray Observatory combined with Hubble Space Telescope imaging, scientists have uncovered first time evidence that NGC 3393 is harboring twin supermassive black holes. Residing only 490 light years apart, the duo may have been the product of a “minor merger” – where a small and large galaxy met. Although the hypothesis of two black holes within one galaxy isn’t new, it has been difficult to prove because the results of two galaxies combining material would result in a rather ordinary looking spiral.

“The current picture of galaxy evolution advocates co-evolution of galaxies and their nuclear massive black holes, through accretion and galactic merging.” says G. Fabbiano, lead author of a recent Nature paper. “Pairs of quasars, each with a massive black hole at the centre of its galaxy, have separations of 6,000 to 300,000 light years and exemplify the first stages of this gravitational interaction.”

If scientific calculations are correct, a smaller galaxy should have contained a smaller mass black hole. This leaves us with an odd situation. If both of these newly discovered black holes have similar mass, shouldn’t the merging pair also be of similar mass? If so, how could a minor merger be the answer?

“The final stages of the black-hole merging process, through binary black holes and final collapse into a single black hole with gravitational wave emission, are consistent with the sub-light-year separation inferred from the optical spectra and light-variability of two such quasars. The double active nuclei of a few nearby galaxies with disrupted morphology and intense star formation demonstrate the importance of major mergers of equal-mass spiral galaxies in this evolution.” says Fabbiano. “Minor mergers of a spiral galaxy with a smaller companion should be a more common occurrence, evolving into spiral galaxies with active massive black-hole pairs, but have hitherto not been seen. The regular spiral morphology and predominantly old circum-nuclear stellar population of this galaxy, and the closeness of the black holes embedded in the bulge, provide a hitherto missing observational point to the study of galaxy/black hole evolution.”

Lay down your bets, gentlemen… It seems the game changes each time it is played!

Original Story Source: Chandra News. For Further Reading: A close nuclear black-hole pair in the spiral galaxy NGC 3393.

Posted on by Tammy Plotner

Chandra Captures Enticing Evidence Of Black Hole’s Bondi Radius

The galaxy NGC 3115 is shown here in a composite image of data from NASA's Chandra X-ray Observatory and the European Southern Observatory's Very Large Telescope (VLT). Credit: X-ray: NASA/CXC/Univ. of Alabama/K.Wong et al, Optical: ESO/VLT

[/caption]

Those who are interested in black holes are familiar with the event horizon, but the Chandra X-Ray Observatory is giving us an even more detailed look into the structure surrounding these enigmas by imaging the inflowing hot gases. Galaxy NGC 3115 contains a supermassive black hole at its heart and for the first time astronomers have evidence of a critical threshold known as the “Bondi radius”.

Located approximately 32 million light years from the Solar System in the constellation of Sextans, NGC 3115 is a prime candidate for study. Contained in its nucleus is a billion-solar-mass black hole which is stripping away hot gases from nearby stars which can be imaged in X-ray. “The Chandra data are shown in blue and the optical data from the VLT are colored gold. The point sources in the X-ray image are mostly binary stars containing gas that is being pulled from a star to a stellar-mass black hole or a neutron star. The inset features the central portion of the Chandra image, with the black hole located in the middle.” says the team. “No point source is seen at the position of the black hole, but instead a plateau of X-ray emission coming from both hot gas and the combined X-ray emission from unresolved binary stars is found.”

In order to see the machination of the black hole at work, the Chandra team eradicated the signal given off by the binary stars, separating it from the super-heated gas flow. By observing the gas at varying distances the team could then pinpoint a threshold where the gas first becomes impacted by the supermassive black hole’s gravity and begins moving towards the center. This point is known as the Bondi radius.

“As gas flows toward a black hole it becomes squeezed, making it hotter and brighter, a signature now confirmed by the X-ray observations. The researchers found the rise in gas temperature begins at about 700 light years from the black hole, giving the location of the Bondi radius.” says the Chandra team. “This suggests that the black hole in the center of NGC 3115 has a mass of about two billion times that of the Sun, supporting previous results from optical observations. This would make NGC 3115 the nearest billion-solar-mass black hole to Earth.”

Original Story Source: Chandra News Further Reading: Resolving the Bondi Accretion Flow toward the Supermassive Black Hole of NGC 3115 with Chandra.

Posted on by Tammy Plotner

Catch A Pulsar By The Tail

A pulsar located about 1,600 light years from Earth.

Originally discovered by the Fermi Gamma Ray Space Telescope in 2009, Pulsar PSR J0357 had a bit of a surprise for astronomers when NASA’s Chandra X-ray Observatory turned an eye its way. Even though it might be 1,600 light years from Earth and half a million years old, it would appear this object has a cosmic sense of humor. Stretching across 4.2 light years is an enormous tail…

Viewable only at X-ray wavelengths, this incredible cosmic contrail is the longest ever associated with a so-called “rotation- powered” pulsar. Unlike other pulsars, J0357 gets its power from energy depletion as the spin rate decreases. But where did the plumage come from? According to the Chandra data, it may be an emission from energetic particles in the pulsar wind produced while turning around magnetic field lines. While artifacts of this type have been noted before, they’re classed as bow-shocks generated by the supersonic motion of pulsars through space. From there, the wind pulls the particles along behind it as the pulsar passes through interstellar gas.

But Pulsar PSR J0357 isn’t exactly fitting into a neat a tidy category…

According to data taken from Fermi, J0357 is only losing a small amount of energy as its spin rate slows. This means it shouldn’t be producing a particle wind of such proportions. Another anachronism is the placement of the bright portions of the tail – not anywhere near where bow-shocks are associated with pulsars.

“Further observations with Chandra could help test this bow-shock interpretation.” says the Chandra team. “If the pulsar is seen moving in the opposite direction from that of the tail, this would support the bow-shock idea.”

Original News Source: Chandra News.

Posted on by Jason Major

A Four Cluster Pile-Up

Abell 2744, a.k.a. "Pandora's Cluster"

[/caption]

Abell 2744, shown above in a composite of images from the Hubble Space Telescope, the ESO’s Very Large Telescope and NASA’s Chandra X-ray  Observatory, is one of the most complex and dramatic collisions ever seen between galaxy clusters.

X-ray image of Abell 2744

Dubbed “Pandora’s Cluster”, this is a region 5.9 million light-years across located 3.5 billion light-years away. Many different kinds of structures are found here, shown in the image as different colors. Data from Chandra are colored red, showing gas with temperatures in the millions of degrees. Dark matter is shown in blue based on data from Hubble, the European Southern Observatory’s VLT array and Japan’s Subaru telescope. Finally the optical images showing the individual galaxies have been added.

Even though there are many bright galaxies visible in the image, most of the mass in Pandora’s Cluster comes from the vast areas of dark matter and extremely hot gas. Researchers made the normally invisible dark matter “visible” by identifying its gravitational effects on light from distant galaxies. By carefully measuring the distortions in the light a map of the dark matter’s mass could be created.

Galaxy clusters are the largest known gravitationally-bound structures in the Universe, and Abell 2744 is where at least four clusters have collided together. The vast collision seems to have separated the gas from the dark matter and the galaxies themselves, creating strange effects which have never been seen together before. By studying the history of events like this astronomers hope to learn more about how dark matter behaves and how the different structures that make up the Universe interact with each other.

Check out this HD video tour of Pandora’s Cluster from the team at Chandra:

Read more on the Chandra web site or in the NASA news release.

Image credit: X-ray: NASA/CXC/ITA/INAF/J.Merten et al, Lensing: NASA/STScI; NAOJ/Subaru; ESO/VLT, Optical: NASA/STScI/R.Dupke.

___________________

Jason Major is a graphic designer, photo enthusiast and space blogger. Visit his website Lights in the Dark and follow him on Twitter @JPMajor or on Facebook for the most up-to-date astronomy awesomeness!

 

Posted on by Tammy Plotner

Black Hole Devours Star and Hurls Energy Across 3.8 Billion Light Years

What University of Warwick researchers think the star may have looked like at the start of its disruption by a black hole at the center of a galaxy 3.8 billion light years distant resulting in the outburst known as Sw 1644+57. Credit: University of Warwick / Mark A. Garlick

[/caption]

Engaging the Hubble Space Telescope, Swift satellite and the Chandra X-ray Observatory, astronomers at the University of Warwick were quick to pick up a signal from Swift’s Burst Alert Telescope on March 28, 2011. In a classic line from Easy Rider, Jack Nicholson says: “It’s a UFO beaming back at you.” But this time it isn’t a UFO… it’s the death scream of a star being consumed by a black hole. The alert was just the beginning of a series of x-ray blasts that turned out to be the largest and most luminous event so far recorded in a distant galaxy.

Originating 3.8 billion light years from Earth in the direction of the constellation of Draco, the beam consisting of high energy X-rays and gamma-rays remained brilliant for a period of weeks after the initial event. As more and more material from the doomed star crossed over the event horizon, bright flares erupted signaling its demise. Says Dr. Andrew Levan, lead researcher on the paper from the University of Warwick; “Despite the power of this the cataclysmic event we still only happen to see this event because our solar system happened to be looking right down the barrel of this jet of energy”.

Dr Andrew Levan is a researcher at the University of Warwick.
Dr. Levan’s findings were published today in the Journal Science in a paper entitled “An Extremely Luminous Panchromatic Outburst from the Nucleus of a Distant Galaxy”. His findings leave no doubt as to the origin of the event and it has been cataloged as Sw 1644+57.

“The only explanation that so far fits the size, intensity, time scale, and level of fluctuation of the observed event, is that a massive black at the very centre of that galaxy has pulled in a large star and ripped it apart by tidal disruption.” says Levan. “The spinning black hole then created the two jets one of which pointed straight to Earth.”

And straight into our eager eyes…

Original Story Source: Eurekalert.

Posted on by Tammy Plotner

Baby Black Holes Grew Up Fast

This composite image from NASA's Chandra X-ray Observatory and Hubble Space Telescope (HST) combines the deepest X-ray, optical and infrared views of the sky. X-ray: NASA/CXC/U.Hawaii/E.Treister et al; Infrared: NASA/STScI/UC Santa Cruz/G.Illingworth et al; Optical: NASA/STScI/S.Beckwith et al

[/caption]

For more than six weeks, the watchful eye of NASA’s Chandra X-ray Observatory kept track of a small portion of sky dubbed the Chandra Deep Field South (CDFS). Its object was to research 200 distant galaxies dating back to about 800 million to 950 million years old. What Chandra was looking for was evidence of massive black holes. The deepest evidence yet…

When combined with very deep optical and infrared images from NASA’s Hubble Space Telescope, the new Chandra data leads astronomers to speculate that young black holes may have evolved in unison with their young galaxies. “Until now, we had no idea what the black holes in these early galaxies were doing, or if they even existed,” said Ezequiel Treister of the University of Hawaii, lead author of the study appearing in the June 16 issue of the journal Nature. “Now we know they are there, and they are growing like gangbusters.”

What does this new information mean? The massive growth of the black holes in the CDFS are just shy of being a quasar – the super-luminous by-product of material slipping over the event horizon. “However, the sources in the CDFS are about a hundred times fainter and the black holes are about a thousand times less massive than the ones in quasars.” How often did it occur in the new data? Try between 30 and 100% of the case studies, resulting in a estimated 30 million supermassive black holes in the early Universe.

“It appears we’ve found a whole new population of baby black holes,” said co-author Kevin Schawinski of Yale University. “We think these babies will grow by a factor of about a hundred or a thousand, eventually becoming like the giant black holes we see today almost 13 billion years later.”

While the existence of these early black holes had been predicted, no observation had been made until now. Due to their natural “cloaking devices” of gas and dust, optical observation had been prohibited, but x-ray signatures don’t lie. The concept of tandem black hole / galaxy growth has been studied closer to home, but taking a look further back into time and space has revealed growth a hundred times more than estimated. These new Chandra results are teaching us that this connection begins at the beginning.

“Most astronomers think in the present-day universe, black holes and galaxies are somehow symbiotic in how they grow,” said Priya Natarajan, a co-author from Yale University. “We have shown that this codependent relationship has existed from very early times.”

Theories also abound which imply neophyte black holes may have played “an important role in clearing away the cosmic “fog” of neutral, or uncharged, hydrogen that pervaded the early universe when temperatures cooled down after the Big Bang”. But to the contrary, the new Chandra findings point towards the pervasive materials stopping ultraviolet radiation before the re-ionization process can occur. Resultant stars and dormant black holes are the most likely culprit to have cleared space for the cosmic dawn.

Although the Chandra X-ray Observatory is up to the task of picking up on uber-faint objects at incredible distances, these baby black holes are so veiled that only a few photons can slip through, making individual detection impossible. To gather this new data, the team employed Chandra’s directional abilities and tallied the hits near the positions of distant galaxies and found a statistically significant signal.

Original Story Source: Chandra News.

Posted on by Nancy Atkinson

Nearby Galaxy Has Two Monster Black Holes

Viewed in visible light, Markarian 739 resembles a smiling face. Inside are two supermassive black holes, separated by about 11,000 light-years. The galaxy is 425 million light-years away from Earth. Credit: Sloan Digital Sky Survey

[/caption]

Why does this galaxy appear to be smiling? The answer might be because it has been holding a secret that astrophysicists have only now just uncovered: there are two — count ‘em – two gigantic black holes inside this nearby galaxy, named Markarian 739 (or NGC 3758), and both are very active. While massive black holes are common, only about one percent of them are considered as active and powerful – called active galactic nuclei (AGN). Binary AGN are rarer still: Markarian 739 is only the second identified within half a billion light-years from Earth.

Markarian 739 is actually a pair of merging galaxies. For decades, astronomers have known that the eastern nucleus of Markarian 739 contains a black hole that is actively accreting matter and generating an exceptional amount of energy. Now, data from the Swift satellite along with the Chandra X-ray Observatory Swift has revealed an AGN in the western half as well. This makes the galaxy one of the nearest and clearest cases of a binary AGN.

The galaxy is 425 million light-years away from Earth.

How did the second AGN remain hidden for so long? “Markarian 739 West shows no evidence of being an AGN in visible, ultraviolet and radio observations,” said Sylvain Veilleux, a professor of astronomy at University of Maryland in College Park , and a coauthor of a new paper published in Astrophysical Journal Letters. “This highlights the critical importance of high-resolution observations at high X-ray energies in locating binary AGN.”

Since 2004, the Burst Alert Telescope (BAT) aboard Swift has been mapping high-energy X-ray sources all around the sky. The survey is sensitive to AGN up to 650 million light-years away and has uncovered dozens of previously unrecognized systems.

Michael Koss, the lead author of this study, from NASA’s Goddard Space Flight Center and UMCP, did follow-up studies of the BAT mapping and he and his colleagues published a paper in 2010 that revealed that about a quarter of the Swift BAT AGN were either interacting or in close pairs, with perhaps 60 percent of them poised to merge in another billion years.

“If two galaxies collide and each possesses a supermassive black hole, there should be times when both black holes switch on as AGN,” said coauthor Richard Mushotzky, professor of astronomy at UMCP. “We weren’t seeing many double AGN, so we turned to Chandra for help.”

Swift’s BAT instrument is scanning one-tenth of the sky at any given moment, its X-ray survey growing more sensitive every year as its exposure increases. Where Swift’s BAT provided a wide-angle view, the X-ray telescope aboard the Chandra X-ray Observatory acted like a zoom lens and resolved details a hundred times smaller.

The distance separating the two black holes is about 11,000 light-years , or about a third of the distance separating the solar system from the center of our own galaxy. The dual AGN of Markarian 739 is the second-closest known, both in terms of distance from one another and distance from Earth. However, another galaxy known as NGC 6240 holds both records.

Source: Swift Telescope webpage

You can follow Universe Today senior editor Nancy Atkinson on Twitter: @Nancy_A. Follow Universe Today for the latest space and astronomy news on Twitter @universetoday and on Facebook.

Posted on by Nancy Atkinson

What Triggers a Type Ia Supernova? Chandra Finds New Evidence

This Chandra image of the Tycho supernova remnant contains new evidence for what triggered the original supernova explosion. Credit: NASA/CXC/Chinese Academy of Sciences/F. Lu et al.

[/caption]

What makes a star go boom? A new look at Tycho’s supernova remnant by the Chandra X-ray telescope has supplied astronomers with previously unseen evidence for what could trigger specific type of supernova, a Type Ia supernova explosion. Astronomers have spotted what appears to be material that was blasted off a companion star to a white dwarf when it exploded, creating the supernova seen by Danish astronomer Tycho Brahe in 1572. There is also evidence that this material blocked the explosion debris, creating an “arc” and a “shadow” in the supernova remnant.

There are two main types of supernovae. One is where a massive star – much bigger than our sun — burns all its nuclear fuel and collapses in on itself, which ignites a supernova explosion. Type Ia supernovae, however, are different. Smaller stars eventually turn into white dwarfs at the end of their lives, becoming an ultra-dense ball of carbon and oxygen about the size of the Earth, with the mass of our Sun. In some instances, though, a white dwarf somehow ignites, creating an explosion so bright that it can be seen billions of light years away, across much of the Universe. But astronomers really haven’t understood what causes these explosions to start.

There are a couple of popular theories: one scenario for Type Ia supernovas involves the merger of two white dwarfs. In this case, no companion star or evidence for material blasted off a companion should exist. In the other theory, a white dwarf pulls material from a “normal,” or Sun-like, companion star until a thermonuclear explosion occurs.

Both scenarios may actually occur under different conditions, but the latest Chandra result from Tycho supports the latter one.

This is an artist's impression showing an explanation from scientists for the origin of an X-ray arc in Tycho's supernova remnant. Credit: NASA/CXC/M.Weiss

The new Chandra images show the famous leftovers of Tycho’s supernova, and reveal for the first time an arc of X-ray emission within the supernova remnant. The shape of the arc is different from any other feature seen in the remnant. This supports the conclusion that a shock wave created the arc when a white dwarf exploded and blew material off the surface of a nearby companion star.

In addition, this new study seems to show how resilient some stars can be, as the supernova explosion appears to have blasted very little material off the companion star. Previously, studies with optical telescopes have revealed a star within the remnant that is moving much more quickly than its neighbors, hinting that it could be the missing companion.

“It looks like this companion star was right next to an extremely powerful explosion and it survived relatively unscathed,” said Q. Daniel Wang of the University of Massachusetts in Amherst, a member of the research team whose paper will appear in the May 1st issue of The Astrophysical Journal. “Presumably it was also given a kick when the explosion occurred. Together with the orbital velocity, this kick makes the companion now travel rapidly across space.”

This image shows iron debris in Tycho's supernova remnant. The site of the supernova explosion is shown, as inferred from the motion of the possible companion to the exploded white dwarf. The position of material stripped off the companion star by the explosion, and forming an X-ray arc, is shown by the white dotted line. This structure is most easily seen in an image showing X-rays from the arc's shock wave. Finally, the arc has blocked debris from the explosion creating a "shadow" in the debris between the red dotted lines, extending from the arc to the edge of the remnant. Credit: NASA/CXC/Chinese Academy of Sciences/F. Lu et al.

Using the properties of the X-ray arc and the candidate stellar companion, the team determined the orbital period and separation between the two stars in the binary system before the explosion. The period was estimated to be about 5 days, and the separation was only about a millionth of a light-year, or less than a tenth the distance between the Sun and the Earth. In comparison, the remnant itself is about 20 light-years across.

Other details of the arc support the idea that it was blasted away from the companion star. For example, the X-ray emission of the remnant shows an apparent “shadow” next to the arc, consistent with the blocking of debris from the explosion by the expanding cone of material stripped from the companion.

“This stripped stellar material was the missing piece of the puzzle for arguing that Tycho’s supernova was triggered in a binary with a normal stellar companion,” said Fangjun Lu of the Institute of High Energy Physics, Chinese Academy of Sciences in Beijing. “We now seem to have found this piece.”

Because Type Ia supernova are all of similar brightness, they are used as a standard candle to measure the expansion of the Universe, and this new observation by Chandra has helped to answer at least part of the long-standing – and critical — question of what triggers these bright explosions.

Source: Chandra