Tag: Chandra

Two giant clusters of galaxies on target for second collision

3:55 pm

Colliding galaxy clusters
Click for full image.

Using telescopes both on Earth and in space, astronomers now think two giant clusters of galaxies that had collided previously have now stopping flying from each other and are on target for second collision.

The annotated image to the right shows what we can see today. The two blue blobs near the center are the two galaxy clusters.

The galaxy cluster PSZ2 G181.06+48.47 (PSZ2 G181 for short) is about 2.8 billion light-years from Earth. Previously, radio observations from the LOw Frequency ARray (LOFAR), an antenna network in the Netherlands, spotted parentheses-shaped structures on the outside of the system. In this new composite image, X-rays from Chandra (represented in purple) and ESA’s XMM-Newton (blue) have been combined with LOFAR data (red) and an optical image from the Pan-STARRS telescope of the stars in the field of view.

These structures are probably shock fronts — similar to those created by jets that have broken the sound barrier — likely caused by disruption of gas from the initial collision about a billion years ago. Since the collision they have continued traveling outwards and are currently separated by about 11 million light-years, the largest separation of these kinds of structures that astronomers have ever seen.

Now, data from NASA’s Chandra and ESA’s XMM-Newton, a mission with NASA contributions, is providing evidence that PSZ2 G181 is poised for another collision. Having a first pass at ramming each other, the two clusters have slowed down and begun heading back toward a second crash.

When such giant object collide what really interacts the most is the gas and dust between the stars. The motions of the stars and galaxies of course get distorted by the pull of gravity, but there are almost never any crashes.

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Astronomers discover a star radiating in X-rays and radio in ways that fit no known explanation

10:14 am

ASKAP J1832 circled. Note the red arc denoting the supernovae remnant
ASKAP J1832 circled. Note the red arc denoting
the supernovae remnant. Click for original image.

Using both the Chandra X-Ray Observatory and the Square Kilometer Array in Australia, astronomers have discovered a star that pulses in both X-rays and and radio frequencies in a manner previously unseen and that fit no known theory.

ASKAP J1832 belongs to a class of objects called “long period radio transients,” discovered in 2022, that vary in radio wave intensity in a regular way over tens of minutes. This is thousands of times longer than the length of the repeated variations seen in pulsars, which are rapidly spinning neutron stars that have repeated variations multiple times a second. ASKAP J1832 cycles in radio wave intensity every 44 minutes, placing it into this category of long period radio transients.

Using Chandra, the team discovered that ASKAP J1832 is also regularly varying in X-rays every 44 minutes. This is the first time that such an X-ray signal has been found in a long period radio transient.

…However, that is not all ASKAP J1832 does. Using Chandra and the SKA Pathfinder, the team found that ASKAP J1832 also dropped off in X-rays and radio waves dramatically over the course of six months. This combination of the 44-minute cycle in X-rays and radio waves in addition to the months-long changes is unlike anything astronomers have seen in the Milky Way galaxy.

The false-color X-ray/radio image to the right shows the star (circled). Based on the data, it is unlikely that the star is a neutron star or a pulsar. Its properties also do not fit with a magnetar (a pulsar with a very strong magnetic field). Though located within a supernova remnant, the astronomers determined this to be a coincidence, the star unrelated to the remnant.

The best explanation so far is that this is a white dwarf with a companion and the strongest magnetic field ever conceived. The astronomers however do not appear enthused by that explanation either.

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Giant galactic magnetic filament disturbed by pulsar

12:18 pm

A giant galactic filament disturbed by a pulsar
Click for original image.

Cool image time! The false-color X-ray picture to the right, reduced and sharpened to post here, was released today by the science team for the Chandra X-ray Observatory, showing some interesting astronomical features about 26,000 light years away near the galactic center.

The press release attempts to catch the ignorant press’s interest by referring to the long white filament that crosses this image as “a bone”, implying that this is similar to a medical X-ray of a person’s bones. Hogwash. What we are looking at is a filament of energized particles forced into this long thin shape by the magnetic field lines that exist in the central regions of the Milky Way galaxy.

What makes this X-ray data of interest is shown in the inset. The pulsar appears to have disturbed that filament, pulling those energetic particles away to form a trailing cloud.

In the first composite image, the largely straight filament stretches from the top to the bottom of the vertical frame. At each end of the grey filament is a hazy grey cloud. The only color in the image is neon blue, found in a few specks which dot the blackness surrounding the structure. The blue represents X-rays seen by NASA’s Chandra X-ray Observatory.

In the annotated close-up, one such speck appears to be interacting with the structure itself. This is a fast-moving, rapidly spinning neutron star, otherwise known as a pulsar. Astronomers believe that this pulsar has struck the filament halfway down its length, distorting the magnetic field and radio signal.

As big and empty as space is, there is still enough stuff within it to cause these kinds of interactions. It just requires the luxury of endless eons, something that we as short-lived humans have trouble conceiving.

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Senate gives NASA cash to stop its tantrum

9:35 am

Surprise, surprise! As expected after NASA proposed major cuts in several missions, such as the Chandra Space Telescope and the OSAM demo robotic refueling mission, the subcommittee of the Senate Appropriations Committee has rejected those cuts and instead proposed that NASA not only get everything it asked for, it be forced to take more money than it requested.

I am certain that NASA is not going to complain, as this was its plan from day one. The cancellation of Chandra was intended as a toddler’s tantrum that our weak Congress was certain to bow to and come up with the cash. It has now done so.

The report directs NASA to spend at least $98.3 million on Hubble and up to $72.1 million on Chandra, similar to the budgets for those missions in recent years, emphasizing the ability of the telescopes to work in conjunction with the James Webb Space Telescope.

In this case the Senate action makes some sense, as these cuts would have been penny wise and pound foolish. But NASA knew that. If the Senate was really interested in controlling the budget (which it is not) it would have funded Chandra and Hubble as described, but demanded cuts from NASA elsewhere.

Instead the Senate committee not only demands that these telescopes be maintained, it doles out extra money the nation doesn’t have for other projects that NASA wanted to cut for entirely legitimate reasons. OSAM for example was conceived more than a decade ago as a mission designed to demonstrate robotic refueling in space. After spending a billion and a decade, it had still not flown, and during that time private companies had not only successfully demonstrated this capability several times for far less, they had done so in a far simpler and more profitable manner. The technical need for OSAM was gone. Why spend the additional billion we can’t afford for a project that will prove nothing?

Congress, especially the Senate, likes wasting money however, and so the appropriations committee in an entirely bi-partisan effort is pushing to revive OSAM, as well as several other projects that have either gone over budget or NASA had deemed correctly were unaffordable.

The dark age has already begun in many ways, but its official start will be marked by future historians by the date the United States undergoes a full financial collapse, due to its government’s unwillingness to rein in a national debt that is now in the many many trillions and growing uncontrollably each day.

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New collection of X-ray false-color Chandra images

9:30 am

Chandra image of galaxy
Click for original image.

Cool image time! As part of a PR campaign by NASA to convince Congress to give it more money to keep the Chandra X-ray Observatory funded, the agency this week released twenty-five new images, supposedly to celebrate the space telescope’s 25th anniversary since launch.

It must be emphasized that these photos are not solely produced by Chandra. They combine its X-ray data wth optical data from Hubble and infrared data from a number of other telescopes.

The picture to the right is of the galaxy NGC 6872 that is interacting with its nearby smaller neighbor. From the caption:

NGC 6872 is 522,000 light-years across, making it more than five times the size of the Milky Way galaxy; in 2013, astronomers from the United States, Chile, and Brazil found it to be the largest-known spiral galaxy, based on archival data from NASA’s Galaxy Evolution Explorer. This record was surpassed by NGC 262, a galaxy that measures 1.3 million light-years in diameter.

Chandra will get its funding to continue operations. NASA is simply playing its old game of bluff with Congress to force it to give the agency a boost in funding. Like a toddler throwing a tantrum, it cancels a successful project, citing funding shortages (even though those shortages are almost always because of mismanagement elsewhere in the agency), and Congress eventually gives in like a weak parent, raising NASA’s budget.

The big image release this week is part of that game. Nonetheless, the images are spectacular, and loaded with new information not otherwise available without Chandra’s X-ray capabilities. If Congress had any spine, it would force NASA to fully fund such successful projects and simply delete the failed ones (such as SLS and Mars Sample Return). It has no spine, however, and thus we have a national debt in the trillions that is bankrupting us.

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Movies of two supernovae remnants produced from two decades of Chandra X-ray images

9:51 am

Using more than two decades of data from the Chandra X-ray Observatory, scientists have created two movies of the supernovae remnants the Crab nebula and Cassiopeia A.

I have embedded those movies below. From the press release:

Over 22 years, Chandra has taken many observations of the Crab Nebula. With this long runtime, astronomers see clear changes in both the ring and the jets in the new movie. Previous Chandra movies showed images taken from much shorter time periods — a 5-month period between 2000 and 2001 and over 7 months between 2010 and 2011 for another. The longer timeframe highlights mesmerizing fluctuations, including whip-like variations in the X-ray jet that are only seen in this much longer movie. A new set of Chandra observations will be conducted later this year to follow changes in the jet since the last Chandra data was obtained in early 2022.

…Cassiopeia A (Cas A for short) is the remains of a supernova that is estimated to have exploded about 340 years ago in Earth’s sky. While other Chandra movies of Cas A have previously been released, including one with data extending from 2000 to 2013, this new movie is substantially longer featuring data from 2000 through to 2019.

» Read more

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Chandra X-rays a giant hand in space

3:54 pm

A cosmic hand
Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken by the Chandra X-ray Observatory, with data from the orbiting IXPE producing the lines that indicate the orientation of the magnetic field lines.

The image was part of research studying what the scientists call Pulsar Wind Nebulae (PWNe).

[E]arly-on when the new-born pulsar is still deep in its parent supernova remnant, or at late times after it has escaped to the relatively uniform interstellar medium, the pulsar wind is often uniform around the pulsar spin or velocity axis. In projection on the sky such structures have bilateral symmetry, that is, the two halves mirror each other. This makes them look (vaguely) like animals. This has led to many PWNe collecting animal monikers (‘The Mouse’, ‘The Dragonfly’, ‘The Rabbit’ – we are guilty of some of these…).

In between these early and late phases, the story is often more complex and the PWN interaction with the supernova shock wave leads to complicated morphologies. One of the prime examples is the PWN in the supernova remnant RCW 89 (also known as MSH 15-5(2)). Here the complex interactions form the PWN into the `Cosmic Hand’. Wanting to map the magnetic fields which structure this hand, the IXPE team took a long hard stare at MSH 15-5(2) and its central pulsar.

The scientists admit that the match between IXPE’s data and the structure of the hand is not really a surprise, but confirming the match was necessary if they are ever going to figure out the fundamental laws that govern magnetic fields, laws that presently are not well understood, at all.

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New data better maps the supernova remnant SN1006

10:50 am

SN1006, as seen in X-rays
Click for original image.

Using data from both the Chandra X-ray Observatory and the Imaging X-ray Polarimetry Explorer (IXPE), scientists have now better mapped the magnetic field and the remnant from the supernova that occurred in 1006 AD.

The false color image to the right shows this data. From the caption:

The red, green, and blue elements reflect low, medium, and high energy X-rays, respectively, as detected by Chandra. The IXPE data, which measure the polarization of the X-ray light, is show in purple in the upper left corner, with the addition of lines representing the outward movement of the remnant’s magnetic field.

From the press release:

Researchers say the results demonstrate a connection between the magnetic fields and the remnant’s high-energy particle outflow. The magnetic fields in SN 1006’s shell are somewhat disorganized, per IXPE’s findings, yet still have a preferred orientation. As the shock wave from the original explosion passes through the surrounding gas, the magnetic fields become aligned with the shock wave’s motion. Charged particles are trapped by the magnetic fields around the original point of the blast, where they quickly receive bursts of acceleration. Those speeding high-energy particles, in turn, transfer energy to keep the magnetic fields strong and turbulent.

At present scientists really do not understand the behavior of stellar-sized magnetic fields. It is very complex, involving three dimensional movements that are hard to measure, as well as electromagnetic processes that are not well understood. While this new data doesn’t provide an explanation, it does tell us better what is actually happening. The theories will follow.

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Chandra: New X-ray composite images of galaxies and supernovae remnants

10:51 am

Chandra image
Click for original image.

The science team for the Chandra X-Ray observatory today released five new composite images of two galaxies, two supernovae remnants, and the center of the Milky Way, combining data from multiple telescopes looking in radio, infrared, optical, and X-ray wavelengths.

The image to the right, reduced and sharpened to post here, is one of those pictures. From the press release:

As the galaxy moves through space at 1.5 million miles per hour, it leaves not one — but two — tails behind it. These tails trailing after ESO 137-001 are made of superheated gas that Chandra detects in X-rays (blue). ESO’s Very Large Telescope shows light from hydrogen atoms (red), which have been added to the image along with optical and infrared data from Hubble (orange and cyan).

The inset shows just the Hubble optical image, reduced by about 50%, to get a clearer sense of the galaxy itself. It appears to be a jelly-fish galaxy, flying through space at right angles to its plane and with tendrils of stars trailing off below.

The other four images are as interesting. The full set, including separate images in the individual wavelengths prior to combination, can be found here.

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Webb and Chandra take composite X-ray/infrared images of four famous objects

5:56 pm

Composite Chandra/Webb image of M16
Click for original image.

Astronomers have now used the Chandra X-ray Observatory and Webb Space Telescope (working in the infrared) to produce spectacular composite false-color X-ray/infrared images of four famous heavenly objects.

To the right is the composite taken of the Eagle Nebula, also known as Messier 16. It was also dubbed the Pillars of Creation when it was one of the first Hubble images taken after the telescope’s mirror focus was fixed in 1993. From the caption:

The Webb image shows the dark columns of gas and dust shrouding the few remaining fledgling stars just being formed. The Chandra sources, which look like dots, are young stars that give off copious amounts of X-rays. (X-ray: red, blue; infrared: red, green, blue)

The other images include star cluster NGC 346 in a nearby galaxy, the spiral galaxy NGC 1672, and the face-on spiral galaxy Messier 74.

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Chandra takes an X-ray look at early Webb infrared observations

9:54 am

Chandra's X-ray vision of the Cartwheel Galaxy
Chandra’s X-ray view of the Cartwheel Galaxy

Webb's view of the Cartwheel Galaxy
Webb’s infrared view of the Cartwheel Galaxy
Click for full image.

Hubble's optical view of the Cartwheel Galaxy
Hubble’s optical view of the Cartwheel Galaxy. Click for original image.

Astronomers have now taken X-ray images using the orbital Chandra X-ray Observatory of four of the first Webb Space Telescope observations. The four targets were the Cartwheel Galaxy, Stephan’s Quintet, galaxy cluster SMACS 0723.3–7327, and the Carina Nebula.

The three images to the right illustrate the importance of studying astronomy across the entire electromagnetic spectrum. Each shows the Cartwheel Galaxy as seen by three of the world’s most important space-based telescopes, each looking at the galaxy in a different wavelength.

The top picture is Chandra’s new X-ray observations. As the press release notes,

Chandra data generally show higher-energy phenomena (like superheated gas and the remnants of exploded stars) than Webb’s infrared view. … X-rays seen by Chandra (blue and purple) come from superheated gas, individual exploded stars, and neutron stars and black holes pulling material from companion stars.

The middle picture was produced by Webb, shortly after the start of its science operations. It looks at the galaxy in the infrared.

In this near- and mid-infrared composite image, MIRI data are colored red while NIRCam data are colored blue, orange, and yellow. Amidst the red swirls of dust, there are many individual blue dots, which represent individual stars or pockets of star formation. NIRCam also defines the difference between the older star populations and dense dust in the core and the younger star populations outside of it.

The bottom picture was taken by the Hubble Space Telescope in 1995. I have rotated the image to match the others. It looks at the galaxy in optical wavelengths, the wavelengths that our eyes perceive.

Note how bright the central galactic region is in the infrared and optical, but is invisible in X-rays. Chandra is telling us that all the most active regions in the Cartwheel are located in that outer ring, not in its center.

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Astronomers: A supermassive black hole rotates far slower than expected

9:53 am

Quasar as seen across multiple wavelengths
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The uncertainty of science: Using Chandra astronomers have measured the rotation of a supermassive black hole in a distant quasar about 3.4 billion light years away and found that it spins at about half the speed of other less massive black holes.

Because a spinning black hole drags space around with it and allows matter to orbit closer to it than is possible for a non-spinning one, the X-ray data can show how fast the black hole is spinning. The spectrum — that is, the amount of energy as a function wavelength — of H1821+643 indicates that the black hole is rotating at a modest rate compared to other, less massive ones that spin close to the speed of light. This is the most accurate spin measurement for such a massive black hole.

The black hole, thought to weigh between 3 to 30 billion times more than the Sun and is the heaviest such object measured in this way, rotates at about half the speed of light. Why that rotation is less than other smaller black holes remains a question not yet answered, though astronomers suspect it is related to its formation history.

The image above is a composite showing this quasar across multiply wavelengths. X-rays are shown in blue, radio in red, and optical in white.

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Chandra’s camera remains in safe mode

12:12 pm

Though engineers have improvised a work-around that has allowed most of instruments on the Chandra X-Ray observatory to resume science operations, the power supply problem in the telescope’s high resolution camera (HRC) that occurred on February 9th remains unresolved, leaving that camera in safe mode.

The Chandra science instrument and engineering teams continue to analyze the cause of the HRC power supply issue, as well as potential approaches to enable the HRC again. The spacecraft is otherwise healthy and operating normally.

Chandra has been flying now for more than two decades, well past its original mission. For it to begin to have these problems is not surprising, though it will be a great tragedy if it fails just as the James Webb Space Telescope is about to go operational. Ideally astronomers want data from both, as well as Hubble, to cover a wide swath of the electromagnetic spectrum, from the optical to the infrared to X-rays.

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Chandra in safe mode

9:11 am

The Chandra X-ray Observatory last week experienced a loss of power that caused engineers to put the science instruments on the space telescope into safe mode while they investigate the problem.

No further information is presently available.

Chandra has been in orbit since 1999, and is now on an extended mission through 2025. It would be a great tragedy if it failed now, just as the infrared Webb telescope is about to begin operations. The two space telescopes are complementary.

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New Chandra mosaic of galactic center reveals spider-web of magnetism

10:19 am

Magnetic field line at the galactic center
Click for full image.

Scientists today released a spectacular panorama of the center of the Milky Way using X-ray data from the Chandra X-ray Observatory and radio data from the MeerKAT radio telescope in South Africa. The panorama reveals a complex web of magnetic field lines emanating out from the supermassive black hole at the center, Sagittarius A* (pronounced A-star).

Below the fold are reduced versions of the full panorama, unlabeled on the left and labeled on the right. The image to the right, reduced to post here, shows just one single example of those magnetic field lines, dubbed G0.17-0.41 and about 20 light years long. This particular filament is the subject of a paper just published in connection with the release of this panorama. From the press release.

A new study of the X-ray and radio properties of this thread by Q. Daniel Wang of the University of Massachusetts at Amherst suggests these features are bound together by thin strips of magnetic fields. This is similar to what was observed in a previously studied thread. (Both threads are labeled with red rectangles in the [full labeled panorama]. The newly studied one in the lower left, G0.17-0.41, is much farther away from the plane of the Galaxy.) Such strips may have formed when magnetic fields aligned in different directions, collided, and became twisted around each other in a process called magnetic reconnection. This is similar to the phenomenon that drives energetic particles away from the Sun and is responsible for the space weather that sometimes affects Earth.

The image below is fascinating to study because of the wealth of detail it includes, not only of magnetic filaments but of other nearby gas clouds and Sagittarius A* itself.
» Read more

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X-rays from Uranus detected for the 1st time

10:02 am

Composite Uranus image of X-ray and optical data

Astronomers using the Chandra X-ray Observatory in orbit have for the first time detected X-rays coming from the planet Uranus.

In the new study, researchers used Chandra observations taken in Uranus in 2002 and then again in 2017. They saw a clear detection of X-rays from the first observation, just analyzed recently, and a possible flare of X-rays in those obtained fifteen years later. The main graphic [posted to the right] shows a Chandra X-ray image of Uranus from 2002 (in pink) superimposed on an optical image from the Keck-I Telescope obtained in a separate study in 2004. The latter shows the planet at approximately the same orientation as it was during the 2002 Chandra observations.

What could cause Uranus to emit X-rays? The answer: mainly the Sun. Astronomers have observed that both Jupiter and Saturn scatter X-ray light given off by the Sun, similar to how Earth’s atmosphere scatters the Sun’s light. While the authors of the new Uranus study initially expected that most of the X-rays detected would also be from scattering, there are tantalizing hints that at least one other source of X-rays is present.

One explanation could be that the X-rays could be coming from Uranus’s rings, as such X-rays do from Saturn. This is not confirmed as yet however. More data will be needed.

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NASA extends Chandra telescope operation to 2024

8:02 am

NASA has extended its contract with the Smithsonian Astrophysical Observatory in Massachusetts to run the Chandra X-ray Observatory through 2024.

In many ways the longevity of both Hubble and Chandra as well as other space telescopes has demonstrated the robustness of much in-space engineering these days. It suggests that when we finally begin building manned interplanetary spaceships we should have confidence they will operate reliably for long periods.

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An X-ray deep field over six weeks by Chandra finds massive black holes common in early universe

1:29 pm

An X-ray deep field image taken over a six week period by Chandra had found that massive black holes are common in early universe.

These results imply that between 30% and 100% of the distant galaxies contain growing supermassive black holes. Extrapolating these results from the relatively small field of view that was observed to the full sky, there are at least 30 million supermassive black holes in the early Universe. This is a factor of 10,000 larger than the estimated number of quasars in the early Universe.

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The Crab Nebula erupts with flares six days

10:37 pm

In mid-April the Crab Nebula erupted for six days, repeatedly emitting the most powerful flares ever recorded from the supernova remnant.

Scientists think the flares occur as the intense magnetic field near the pulsar undergoes sudden restructuring. Such changes can accelerate particles like electrons to velocities near the speed of light. As these high-speed electrons interact with the magnetic field, they emit gamma rays.

To account for the observed emission, scientists say the electrons must have energies 100 times greater than can be achieved in any particle accelerator on Earth. This makes them the highest-energy electrons known to be associated with any galactic source. Based on the rise and fall of gamma rays during the April outbursts, scientists estimate that the size of the emitting region must be comparable in size to the solar system.

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