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Advertise with Googlier.com Chandra Blog | Fresh Chandra News http://chandra.harvard.edu/blog/ en NASA's Chandra Breaks Down 'Treble Clef's' Galaxy Cluster Collision http://chandra.harvard.edu/blog/node/976 <span>NASA's Chandra Breaks Down 'Treble Clef's' Galaxy Cluster Collision</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field-item"><div style="margin-bottom:20px;text-align:center;"><a href="http://chandra.harvard.edu/photo/2026/trebleclef/"><img src="http://chandra.harvard.edu/photo/2026/trebleclef/trebleclef_525.jpg" alt="A multiwavelength image of the Treble Clef Cluster." width="525" height="391" loading="lazy"></a><br><a href="http://chandra.harvard.edu/photo/2026/trebleclef/"><span style="color:dimgrey;">The Treble Clef Cluster / VLSS J0318.9+5755</span></a><br><a href="http://chandra.harvard.edu/photo/2026/trebleclef/"><span style="color:dimgrey;font-size:14px;text-decoration:underline;">More images, videos, and information</span></a><br><span style="color:dimgrey;font-size:12px;">Credit: X-ray: NASA/CXC/INAF-IRA/A. Botteon et al.; Infrared: UKIDSS-GPS ; Radio: ASTRON/LOFAR; Image Processing: NASA/CXC/SAO/N. Wolk</span></div> <p>Astronomers have used NASA’s Chandra X-ray Observatory to break down the cause of a remarkable formation of radio waves they have nicknamed the “Treble Clef” because its distinct shape strongly resembles the musical symbol.</p> <p>The researchers discovered the Treble Clef is likely caused by an outburst from a supermassive black hole, followed by a collision of two galaxy clusters. A paper describing the findings, led by Andrea Botteon of the National Institute for Astrophysics, or INAF, in Italy, published Wednesday in the Astronomy & Astrophysics journal.</p> <p>An explanation for the Treble Clef has been particularly difficult to find because the formation lies almost directly behind the plane of the Milky Way, meaning that stars, gas, and dust from our home galaxy largely block the view from Earth. However, by using telescopes that can peer through the intervening material, a team of researchers was able to identify what is responsible for this uncommon structure.</p> <p>NASA’s Chandra and the German Extended RÖntgen Survey with an Imaging Telescope Array (eROSITA) X-ray telescope found diffuse, hot gas at the location of the Treble Clef, showing that a galaxy cluster hosts the object. The researchers also determined the galaxy cluster is, in fact, two clusters in the process of merging. Galaxy clusters are some of the largest structures in the universe, containing hundreds of individual galaxies and huge reservoirs of superheated gas.</p> <p>This new composite image of the Treble Clef and its cluster shows the multimillion-degree gas detected in X-rays by Chandra and eROSITA in blue, with some of the Chandra data derived from a special technique the authors used to highlight important features in the Chandra data. Radio data shown in red from the LOw Frequency ARray (LOFAR), a large network of radio telescopes in Europe reveals the doppelganger of the musical notation. The final piece of the combined image comes from infrared data obtained by the United Kingdom Infrared Telescope, appearing mostly white.</p> <p>The authors concluded that the Treble Clef likely formed in a two-stage process. First, an earlier outburst from a supermassive black hole in the galaxy cluster’s center drove clouds of charged particles and magnetic fields away at close to the speed of light. This led to a type of cosmic crescendo and initially produced bright radio waves that later faded as the particles lost energy. Next, the collision between the two clusters compressed or reenergized the cloud, which became brighter again in radio waves. Shock waves — similar to the sonic booms from supersonic jets — from the collision may have played a role in this reenergizing process.</p> <p>To reveal evidence for the cluster collision in the Chandra data, the authors used a special technique that examined how much the cluster’s hot gas deviates from a symmetrical shape. Most of the hot gas is symmetrical and shaped approximately like an oval. The authors removed this symmetrical oval shape from the original X-ray image. The remaining X-ray emission in the residual image shows t is brightest on the left and right, and faintest in the center. The new composite image combines both the original X-ray and the residual X-ray images.</p> <p>The brighter X-rays in the residual image, toward the left and right of the cluster’s center, imply that the collision between the two clusters likely occurred along the left-right direction as seen in the image. The researchers think the direct collision between the two clusters occurred a few hundred million years ago, and the clusters are now moving away from each other.</p> <p>The resemblance to a treble clef is a case of pareidolia, the phenomenon when people see familiar shapes in random data, since there is no scientific connection to the musical notation. A second interpretation of pareidolia for this radio emission structure is a dragon that is being viewed from the side.</p> <div align="center"><video poster="http://chandra.harvard.edu/photo/2026/trebleclef/trebleclef_dragon_preview.jpg" controls width="525"><br> <source src="http://chandra.harvard.edu/photo/2026/trebleclef/trebleclef_dragon.mp4" type="video/mp4"><br> Your browser does not support the video tag.<br> </video><br> </div> <p>NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.</p> </div> <span><span>Chandra</span></span> <span><time datetime="2026-10-14T12:28:39-04:00" title="Wednesday, October 14, 2026 - 12:28">Wed, 10/14/2026 - 12:28</time> </span> <div class="node-taxonomy-container field--name-field-category field--type-entity-reference field--label-above"> <h3 class="term-title"><i class="icon-bookmark"></i> Category</h3> <ul class="taxonomy-terms"> <li class="taxonomy-term"><a href="http://chandra.harvard.edu/blog/taxonomy/term/2" hreflang="en">Groups & Clusters of Galaxies</a></li> </ul> </div> Wed, 14 Oct 2026 16:28:39 +0000 Chandra 976 at http://chandra.harvard.edu/blog Celebrating NASA's Chandra and Swift Exploring Space Together http://chandra.harvard.edu/blog/node/975 <span>Celebrating NASA's Chandra and Swift Exploring Space Together</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field-item"><p><meta charset="utf-8"></p> <div style="margin-bottom:20px;text-align:center;"><a href="http://chandra.harvard.edu/photo/2026/swift/"><img src="http://chandra.harvard.edu/photo/2026/swift/swift_525.jpg" alt="Four composite images of different galaxies presented in a 2 by 2 grid." width="525" height="403" loading="lazy"></a><br><a href="http://chandra.harvard.edu/photo/2026/swift/"><span style="color:dimgrey;">The Small Magellanic Cloud, NGC 1097, NGC 4151, and NGC 1365. </span></a><br><a href="http://chandra.harvard.edu/photo/2026/swift/"><span style="color:dimgrey;font-size:14px;text-decoration:underline;">More images and information</span></a><br><span style="color:dimgrey;font-size:10px;line-height:10px;width:500px;">Credit: NASA/CXC/SAO </span></div> <p>As NASA’s Neil Gehrels Swift Observatory nears its final days in orbit, it is an excellent opportunity to celebrate this telescope and its place in NASA’s fleet of eyes on the universe.</p> <p>NASA’s Chandra X-ray Observatory is one of the many telescopes that frequently teamed up with Swift to make important discoveries about the cosmos. Chandra and Swift have complementary abilities. While Swift can quickly capture rapidly-changing events in space in ultraviolet, X-ray, and gamma-ray light, Chandra is able to gather more detailed data with its sharp X-ray vision. When combined, these two telescopes helped provide a more complete picture of events and objects in space than either could alone.</p> <p>This new image collection is just a sample of the many cosmic objects that Chandra and Swift have both observed in the pursuit of learning more about the mysteries of space</p> <div align="center"><a href="http://chandra.harvard.edu/photo/2026/swift/more.html"><img src="http://chandra.harvard.edu/photo/2026/swift/swift_labeled_525.jpg" alt="A labeled version of the main image showing four images. Labeled are, top left, SMC, top right NGC 1097, bottom left, NGC 4151, and bottom right, NGC 1365." width="525" height="403" loading="lazy"></a><br> <div style="color:dimgrey;font-size:12px;line-height:12px;padding-top:10px;width:400px;"><strong>Chandra & Swift Galaxy Image Collection, Labeled.</strong> Credit: NASA/CXC/SAO<br><br> </div> </div> <p><strong>Top left:</strong> The Small Magellanic Cloud (SMC) is one of the Milky Way’s closest galactic neighbors, and orbits around our home galaxy, at a distance of about 200,000 light-years from Earth. This new view of the SMC contains a multitude of layers of light including ultraviolet data from Swift (magenta and cyan), X-rays from the Chandra X-ray Observatory and ESA’s XMM-Newton (red, green and navy), infrared data from NASA’s retired Spitzer Space Telescope and ESA’s Herschel Space Observatory (orange), and optical data the Cerro Tololo Inter-American Observatory in Chile (pink, peach and purple).</p> <p><strong>Top right:</strong> NGC 1097 is a spiral galaxy about 48 million light-years from Earth that contains a supermassive black hole about 140 million times more massive than our Sun. The region around the black hole glows brightly in X-rays as material nearing the black hole is heated to millions of degrees. In this combined view, X-rays from Chandra (yellow and orange) have been combined with ultraviolet data from Swift (blue) along with an optical light image from Hubble and a ground-based telescope (red, green, and blue).</p> <p><strong>Bottom left:</strong> NGC 4151 is also a spiral galaxy with an actively-growing supermassive black hole at its center. The X-ray emission detected by Chandra (orange) has been attributed to an outburst powered by the black hole. Ultraviolet data and X-ray light detected by Swift (magenta) has been combined with the Chandra data and added to an optical light image taken from the ground by an astrophotographer.</p> <p><strong>Bottom right:</strong> There is another growing giant hole at the center of the galaxy NGC 1365. Astronomers call these very bright cores “active galactic nuclei” (or AGN), which are fueled by a steady flow of material streaming onto the black hole. In this composite, there are X-rays from Chandra (purple) and Swift (magenta), ultraviolet data from Swift (teal), and an optical light image from a ground-based telescope.</p> <p>NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.</p> </div> <span><span>Chandra</span></span> <span><time datetime="2026-10-08T11:04:15-04:00" title="Thursday, October 8, 2026 - 11:04">Thu, 10/08/2026 - 11:04</time> </span> <div class="node-taxonomy-container field--name-field-category field--type-entity-reference field--label-above"> <h3 class="term-title"><i class="icon-bookmark"></i> Category</h3> <ul class="taxonomy-terms"> <li class="taxonomy-term"><a href="http://chandra.harvard.edu/blog/taxonomy/term/2" hreflang="en">Groups & Clusters of Galaxies</a></li> </ul> </div> Thu, 08 Oct 2026 15:04:15 +0000 Chandra 975 at http://chandra.harvard.edu/blog A Cleaner Look at Our Galactic Center's Hot Mess http://chandra.harvard.edu/blog/node/974 <span>A Cleaner Look at Our Galactic Center's Hot Mess</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field-item"><p><meta charset="utf-8"></p> <div style="margin-bottom:20px;text-align:center;"><a href="http://chandra.harvard.edu/photo/2026/sgrae/"><img src="http://chandra.harvard.edu/photo/2026/sgrae/sgrae_525.jpg" alt="An image of the center of our galaxy in different types of light." width="525" height="525" loading="lazy"></a><br><a href="http://chandra.harvard.edu/photo/2026/sgrae/"><span style="color:dimgrey;">Sagittarius A East in our Galactic Center </span></a><br><a href="http://chandra.harvard.edu/photo/2026/sgrae/"><span style="color:dimgrey;font-size:14px;text-decoration:underline;">More images and information</span></a><br><span style="color:dimgrey;font-size:10px;line-height:10px;width:500px;">Credit: X-ray: NASA/CXC/McGill Univ./M. Balakrishnan et al.; Radio: NSF/NRAO/VLA; Sub-mm: EAO/James Clerk Maxwell Telecope; </span><br><span style="color:dimgrey;font-size:10px;line-height:10px;width:500px;">Image Processing: NASA/CXC/SAO/P. Edmonds, N. Wolk</span></div> <p>The center of the Milky Way galaxy is a chaotic place. In addition to the 4-million-solar mass black hole, known as Sagittarius A* (Sgr A*), the region is full of gas, dust, strong magnetic fields, and stars in various stages of life — from birth to death.</p> <p>Now, astronomers have released the clearest view yet of the remains of an exploded star that sits amid this cluttered galactic environment. The supernova remnant is named Sagittarius A East, or Sgr A East, and it is the closest remnant to Sgr A* that astronomers know about.</p> <p>Sgr A East emits light in many wavelengths, including X-rays that NASA’s Chandra X-ray Observatory can see. Supernova remnants like Sgr A East give off X-rays because powerful shock waves rumble outward into space after the explosion and the stellar debris is superheated to millions of degrees.</p> <div align="center"><a href="http://chandra.harvard.edu/photo/2026/sgrae/more.html"><img src="http://chandra.harvard.edu/photo/2026/sgrae/sgrae_labeled_525.jpg" alt="A labeled version of the main image that points out the Sgr East Supernova Site to the left of our galaxy's supermassive black hole, Sgr A*" width="525" height="525" loading="lazy"></a><br> <div style="color:dimgrey;font-size:12px;line-height:12px;padding-top:10px;width:400px;"><strong>Sagittarius A East, labeled.</strong> Credit: X-ray: NASA/CXC/McGill Univ./M. Balakrishnan et al.; Radio: NSF/NRAO/VLA; Sub-mm: EAO/James Clerk Maxwell Telecope; Image Processing: NASA/CXC/SAO/P. Edmonds, N. Wolk<br><br> </div> </div> <p>In this packed galactic landscape, it is difficult to tease out what light is coming from the Sgr A East supernova remnant and what emanates from other objects. Astronomers previously have identified the primary contributors. The two main sources of X-rays in this image, besides the supernova remnant itself, are colliding winds from a cluster of hot, massive stars and a diffuse commingled glow from many fainter overlapping X-ray sources. (This latter category is composed mainly of double star systems including stars like our Sun orbiting white dwarf stars.)</p> <p>This new composite image of Sgr A East and the region around it contains X-rays from Chandra that are not — for the first time — contaminated by X-rays from other sources in this crowded field. A team of astronomers used a special technique to separate the three main sources of X-rays and create this new cleaner view of Sgr A East. This analysis also allowed the authors to make maps of the elements within the supernova remnant, including iron, sulfur, argon, and calcium.</p> <p>The new image of Sgr A East shows lower-energy X-rays detected by Chandra in green and high-energy ones in light blue, which appear purple in the middle of the supernova remnant. The researchers removed the point-like sources of X-rays so they could study the diffuse emission in more detail. The X-ray data have been combined with radio data from the NSF’s Very Large Array in red and submillimeter-wavelength data from the James Clerk Maxwell Telescope in dark blue to complete this new composite view.</p> <p>The bright radio emission surrounds X-rays from Sgr A East as well as the region around Sgr A*. The supermassive black hole is located at the center of the yellow spiral structure to the right of the purple X-rays from Sgr A East.</p> <p>This new image will also allow scientists to examine how the winds from the stars in the nearby cluster have shaped the supernova remnant’s evolution. This could help reveal the identity of the star that exploded to create Sgr A East and whether the supernova remnant has triggered outbursts from Sgr A* in the past.</p> <p>Because Sgr A East is so close to Sgr A*, astronomers have long wondered if they influence one another. The authors’ new work supports the idea that Sgr A East has played an active role in the black hole’s environment by injecting energy into the region and keeping the gas surrounding Sgr A* hot and turbulent over its lifetime of about 10,000 years, although its exact age remains uncertain. They have shown that Sgr A East has expanded into, compressed and heated the gas surrounding it, shaping its three-dimensional asymmetrical structure.</p> <p>A <a href="https://iopscience.iop.org/article/10.3847/1538-4357/ae5dbe/pdf">paper describing these results</a> with these authors appeared in The Astrophysical Journal, and was led by Mayura Balakrishnan from McGill University in Montreal, Canada.</p> <p>NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.</p> </div> <span><span>Chandra</span></span> <span><time datetime="2026-09-30T10:44:50-04:00" title="Wednesday, September 30, 2026 - 10:44">Wed, 09/30/2026 - 10:44</time> </span> <div class="node-taxonomy-container field--name-field-category field--type-entity-reference field--label-above"> <h3 class="term-title"><i class="icon-bookmark"></i> Category</h3> <ul class="taxonomy-terms"> <li class="taxonomy-term"><a href="http://chandra.harvard.edu/blog/taxonomy/term/5" hreflang="en">Supernovas & Supernova Remnants</a></li> <li class="taxonomy-term"><a href="http://chandra.harvard.edu/blog/taxonomy/term/8" hreflang="en">Milky Way Galaxy</a></li> </ul> </div> Wed, 30 Sep 2026 14:44:50 +0000 Chandra 974 at http://chandra.harvard.edu/blog Unearthing the Hidden Universe: How Scientists Use AI to Mine Chandra’s Archive http://chandra.harvard.edu/blog/node/973 <span>Unearthing the Hidden Universe: How Scientists Use AI to Mine Chandra’s Archive</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field-item"><div style="float:left;margin-bottom:5px;margin-right:1em;text-align:center;width:303px;"><a href="http://chandra.harvard.edu/blog/files/images/20years_300_1024_4x5.jpg"><img src="https://chandra.si.edu/blog/files/images/20years_300_303_4x5.jpg" alt="An Artist's illustration of the Chandra X-ray Observatory in space." width="303" height="379" loading="lazy"></a><br><em><span style="color:dimgrey;font-size:12px;">Artist's illustration of the Chandra X-ray Observatory in space. (Credit: NASA/CXC & J.Vaughan)</span></em></div> <p>Over 27 years of observations from NASA's Chandra X-ray Observatory, the agency’s flagship X-ray mission, have created one of astronomy's richest scientific archives. Today, scientists are using artificial intelligence (AI) to uncover discoveries hidden within those decades of collected X-ray data.</p> <p>The Chandra archive is a unique treasure — holding tens of thousands of separate pointings of the telescope and hundreds of millions of seconds of X-ray observations. Because the archive is openly available, scientists (and the public) can revisit decades of observations with new ideas and new tools. This enables new opportunities for discovery that were potentially not possible when the data were first collected.</p> <p>While scientists consistently comb through the Chandra archive and make important and exciting discoveries, modern computational tools allow researchers to analyze this vast reservoir of data at unprecedented scale. This is where AI becomes a powerful scientific tool, serving as an extension of human ingenuity to uncover subtle patterns and produce new cosmic discoveries from invaluable open archives of data.</p> <p>Acting like a microphone to a singer, AI can boost the capabilities of scientists and help them analyze more data and do so more quickly than without it. But just as there would be no song without the singer, there would be no science without the scientists. AI enhances, amplifies, and expands capabilities, but it does not replace what humans do in the scientific process.</p> <p>Researchers decide what questions to ask, they train and evaluate the algorithms, and carefully verify and interpret every result before it becomes part of the scientific record. Whatever an AI system generates still needs to be rigorously checked and interpreted by researchers before those insights can be shared with the wider scientific community.</p> <p>Three recent results show what is possible when Chandra’s vast stores of data, talented astrophysicists, and specialized AI models work together.</p> <ul style="margin-bottom:20px;margin-left:40px;"> <li>In 2024 astronomers reported the discovery of eruptions from supermassive black holes in the centers of seven galaxies.</li> <li>Another team in 2025 reported that a rare type of black hole may have been discovered tearing apart a star.</li> <li>Then, later in 2025 scientists reported discovering many growing supermassive black holes buried beneath thick clouds of gas in a deep X-ray image.</li> </ul> <p>AI can assist Chandra’s X-ray superpowers and enable these discoveries and dramatically accelerate the search for rare objects hidden within decades of observations.</p> <p>Below there are more details on these examples of AI-assisted results using Chandra data. With new telescopes like the Vera Rubin Observatory in Chile and the recently-launched Nancy Grace Roman Telescope, astronomers will have access to more datasets than ever before. When coupled with deep archives from Chandra, Hubble, and other NASA missions, these tools open exciting new pathways for astronomers to use AI to learn more about our universe.</p> <p style="font-size:22px;"><strong>Under the Hood: How AI Unlocked Three Chandra Discoveries</strong></p> <p><strong>1) Finding Hidden Black Hole Outbursts (2024)</strong></p> <div style="float:right;margin-bottom:5px;margin-left:1em;text-align:center;width:303px;"><a href="http://chandra.harvard.edu/photo/2019/phoenix/phoenix.jpg"><img src="http://chandra.harvard.edu/photo/2019/phoenix/phoenix.jpg" alt="This is an X-ray, optical and radio data image of the Phoenix Cluster, a galaxy cluster with a supermassive black hole. The cluster is dominated by purple hues with small pops of red and light blue near the center and dotted with fuzzy pale gold sources throughout. The overall shape resembles a partial distorted spiral shell, with the dots looking like lit up fireflies around it." width="303" height="303" loading="lazy"></a><br><em><span style="color:dimgrey;font-size:12px;line-height:12px;">The Phoenix Cluster</span></em><br><em><span style="color:dimgrey;font-size:12px;line-height:12px;">(Credit: X-ray: NASA/CXC/MIT/M.McDonald et al.; Radio: NRAO/VLA; Optical: NASA/STScI)</span></em></div> <p>Astronomers discovered seven previously unknown eruptions from supermassive black holes by <a href="https://academic.oup.com/mnras/article/527/2/3315/7339785?login=false">using AI to search through years of Chandra observations</a>. Outbursts from material surrounding a black hole can generate jets of energetic particles that displace the hot, X-ray emitting gas surrounding them, creating enormous pairs of cavities. By measuring the size of the cavities, the total amount of energy produced in the outbursts can be calculated, making these studies crucial for understanding the impact of black holes on their galactic neighborhoods. For example, energy released by the expansion of cavities can prevent the hot gas from cooling down and forming huge numbers of new stars. The AI program developed for this task was trained on computer simulations of Chandra data and when applied to real Chandra data, successfully recovered 93 of 97 cavities previously identified in galaxies, and all 14 cavities in clusters of galaxies. The program found seven new pairs of cavities in galaxies, and several other candidates, representing the discovery of powerful outbursts from supermassive black holes.</p> <p><strong>2) Catching a Rare Black Hole Devouring a Star (2025)</strong></p> <div style="float:right;margin-bottom:5px;margin-left:1em;text-align:center;width:303px;"><a href="http://chandra.harvard.edu/photo/2025/ngc6099/ngc6099_unlabeled.jpg"><img src="http://chandra.harvard.edu/photo/2025/ngc6099/ngc6099_303.jpg" alt="An X-ray and optical image of NGC 6099 HLX-1." width="303" height="272" loading="lazy"></a><br><em><span style="color:dimgrey;font-size:12px;line-height:12px;">NGC 6099 HLX-1</span></em><br><em><span style="color:dimgrey;font-size:12px;line-height:12px;">(Credit: X-ray: NASA/CXC/Inst. of Astronomy, Taiwan/Y-C Chang; Optical/UV: NASA/ESA/STScI/HST; Image Processing: NASA/STScI/J. DePasquale)</span></em></div> <p>This <a href="https://iopscience.iop.org/article/10.3847/1538-4357/adc256">paper</a> centered on a black hole that scientists think may have been discovered to be tearing a star apart, a process called a “tidal disruption event”. The search looked for extremely bright galactic sources in other galaxies that are primarily at lower energies than other bright galactic X-ray sources, a possible X-ray calling card for tidal disruptions. The study of such sources offers a unique and powerful opportunity to study matter falling onto supermassive black holes in extreme conditions. These types of sources are rare and difficult to find, so the authors used a double-pronged technique to efficiently search for them in the Chandra archive, using a manually-applied algorithm and a machine learning technique. This search uncovered a new candidate for a tidal disruption. The researchers found indications that the black hole is an elusive type called an “intermediate mass black hole” with a mass in between those of stellar-mass black holes formed from the collapse of massive stars and the supermassive variety found in the centers of galaxies. The event occurred between 2001 and 2002, making it one of the earliest tidal disruption events seen with Chandra.</p> <p><strong>3) Uncovering Buried Giants in the Deep Universe (2025)</strong></p> <div style="float:right;margin-bottom:5px;margin-left:1em;text-align:center;width:303px;"><a href="http://chandra.harvard.edu/photo/2011/cdfs/cdfs_hst_cxo.jpg"><img src="http://chandra.harvard.edu/photo/2011/cdfs/cdfs_hst_cxo.jpg" alt="A multiwavelength image of Chandra Deep Field South (CDFS)." width="303" height="271" loading="lazy"></a><br><em><span style="color:dimgrey;font-size:12px;line-height:12px;">Chandra Deep Field South (CDFS)</span></em><br><em><span style="color:dimgrey;font-size:12px;line-height:12px;">(Credit: 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.)</span></em></div> <p>Scientists have developed theories that predict how many supermassive black holes are hidden under thick clouds of gas. A <a href="https://iopscience.iop.org/article/10.3847/1538-4357/addaab">recent paper using AI</a> helped look for these growing black holes (known as active galactic nuclei, or AGN) in the Chandra Deep Field-South (CDF-S), the most sensitive X-ray image ever obtained. Astronomers have predicted that these deeply buried AGN should make up a significant fraction of the total number of AGN, likely around 30% or more. However, in the CDF-S, only about 11% of the AGN have been identified as deeply buried. An AI technique was applied to the CDF-S to see if more buried AGN could be found. The AI was trained and tested using a set of 210 previously known AGN. The algorithm achieved a success rate of about 90%. The team then applied the AI to an additional group of likely AGN and detected 67 that are deeply buried. This work significantly increased the fraction of buried AGN in the CDF-S, making it closer to theoretical predictions.</p> <p><strong>Conclusion: AI + X-ray = Discovery</strong></p> <p>Ultimately AI is playing a role in expanding how much of the universe we can understand. Modern telescopes like Chandra are amassing giant datasets in their archives — holding undiscovered pieces to the cosmic puzzle. By giving scientists better tools to sift through the wealth of information, we can help ensure that every second of telescope time contributes to yielding new insights about how our universe works. Using AI with the data treasure troves like Chandra’s archive opens up new possibilities for discovery and exploration today and for future generations.</p> <p>— K. Arcand, P. Edmonds, M. Watzke, CXC</p> </div> <span><span>Chandra</span></span> <span><time datetime="2026-09-23T11:39:26-04:00" title="Wednesday, September 23, 2026 - 11:39">Wed, 09/23/2026 - 11:39</time> </span> <div class="node-taxonomy-container field--name-field-category field--type-entity-reference field--label-above"> <h3 class="term-title"><i class="icon-bookmark"></i> Category</h3> <ul class="taxonomy-terms"> <li class="taxonomy-term"><a href="http://chandra.harvard.edu/blog/taxonomy/term/14" hreflang="en">General</a></li> </ul> </div> Wed, 23 Sep 2026 15:39:26 +0000 Chandra 973 at http://chandra.harvard.edu/blog A Hidden Population of Cosmic Beacons: Discovering Hypersoft X-ray Sources with Chandra http://chandra.harvard.edu/blog/node/972 <span>A Hidden Population of Cosmic Beacons: Discovering Hypersoft X-ray Sources with Chandra</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field-item"><div style="float:left;margin-bottom:5px;margin-right:1em;text-align:center;width:303px;"><a href="http://chandra.harvard.edu/blog/files/images/muhibullah_1_864.jpg"><img src="https://chandra.si.edu/blog/files/images/muhibullah_1_303.jpg" alt="Mustafa Muhibullah sitting on a giant boulder in a body of water. He is wearing sunglasses and a red puffer coat. A beautiful snowy mountainscape dotted with evergreen trees is in the background" width="303" height="372" loading="lazy"></a><br><em><span style="color:dimgrey;font-size:12px;">Mustafa Muhibullah (Credit: Mustafa Muhibullah)</span></em></div> <p><em>We welcome Mustafa Muhibullah as a guest blogger. He is the first author of a Nature Astronomy paper that is the subject of </em><a href="http://chandra.harvard.edu/press/26_releases/press_090926.html"><em>our latest press release</em></a><em>. Mustafa is a Ph.D. candidate in Physics & Astronomy at the University of Alabama, working with Prof. Jimmy Irwin since Fall 2021. His research focuses on high-energy astrophysics, particularly faint and compact X-ray sources and galaxy clusters, using NASA’s Chandra X-ray Observatory. He earned his M.S. in Physics from the University of Missouri–Kansas City in 2021 and his B.S. in Mechanical Engineering from Rajshahi University of Engineering & Technology, Bangladesh.</em></p> <p><br> </p> <p><strong>The “Unobserved” Window of the Universe</strong></p> <p>Modern astronomy explores the Universe across nearly the entire electromagnetic spectrum, from radio waves to X-rays. Yet one important window remains largely hidden: the extreme-ultraviolet (EUV), a narrow but energetic region between ultraviolet light and low-energy X-rays. For observers in the Milky Way, EUV radiation from distant sources is almost completely blocked by the cool, neutral hydrogen and helium that fill our Galaxy and readily absorbs these photons before they can reach our telescopes.</p> <p>We know that powerful EUV emitters exist. For example, astronomers know that hot, massive stars, the solar corona, and active galaxies can all produce substantial EUV emission. Fortunately, they also radiate at other wavelengths, allowing astronomers to detect and study them even when their EUV light is absorbed.</p> <p><strong>The Discovery of Hypersoft X-ray Sources</strong></p> <p>Could other EUV-bright objects be hiding in the Universe, producing little detectable emission at other wavelengths? To find them, we took an indirect approach: searching archival observations from NASA’s Chandra X-ray Observatory for faint X-ray signatures from sources whose emission may peak in the EUV.</p> <p>This search revealed a previously unrecognized class of cosmic sources in nearby galaxies, which we dubbed hypersoft X-ray sources (HSSs). They emit almost exclusively at the lowest X-ray energies accessible to Chandra, with little or no emission at higher energies (see Figure 1)—suggesting that much of their radiation may lie in the poorly explored EUV regime that abuts the low-energy X-rays on the electromagnetic spectrum. Their extreme X-ray “softness”, corresponding to the lowest energy X-rays, combined with absorption by intervening material, Chandra’s declining low-energy sensitivity, and their large apparent changes in brightness, likely explains why they remained largely hidden. Despite these challenges, we have been able to identify 84 HSSs in six nearby galaxies, spanning both spiral and elliptical systems, and have just announced the results in a paper in Nature Astronomy.</p> <p><strong>Extremely Bright Yet Exceptionally Cool</strong></p> <p>Although difficult to detect, HSSs can be extraordinarily luminous—in some cases radiating hundreds of thousands to millions of times more energy than the Sun. Their luminosities rival those of ultraluminous X-ray sources (ULXs), some of the brightest known X-ray sources that are not located in the centers of galaxies, where growing supermassive black holes, known as active galactic nuclei, can generate copious amounts of X-rays. Yet while ULXs are relatively rare, we find dozens of HSSs per galaxy in some of the systems we studied, suggesting that HSSs could be one of the most numerous populations of highly luminous, non-nuclear X-ray sources in nearby galaxies.</p> <p>At the same time, their extremely soft emission indicates that HSSs are exceptionally cool for X-ray sources. They may be far hotter than ordinary stars but considerably cooler than most known X-ray-emitting compact objects—a combination that may hold the key to their true nature.</p> <div align="center"><img src="http://chandra.harvard.edu/blog/files/images/muhibullah_2_624.jpg" alt="Two illustrations on top of a data image, presented side-by-side." width="624" height="315" loading="lazy"><br> <div style="color:dimgrey;font-size:13px;line-height:14px;width:400px;"><strong>Figure 1.</strong> Hypersoft X-ray sources (HSSs) in the central region of the elliptical galaxy NGC 3379. The sources are detected almost exclusively at the lowest X-ray energies accessible to Chandra (0.15–0.3 keV; left), with little or no radiation at higher energies (0.3–1.0 keV; right), as indicated by the white ellipses in the insets.<br><strong>Credit:</strong> NASA/SAO/CXC/Mustafa Muhibullah (University of Alabama)<br><br> </div> </div> <p><strong>So, What Are They?</strong></p> <p>Their high luminosities and relatively cool temperatures suggest that HSSs could have large emitting regions, potentially associated with matter falling onto white dwarfs and, for the most luminous sources, perhaps even more massive compact objects such as black holes.</p> <p>Our observations of the nearby galaxy Andromeda (M31) provide an important clue. Several of the least luminous HSSs are associated with novae—explosive events in close binary systems where a white dwarf accumulates hydrogen-rich material from its companion until it ignites in a thermonuclear runaway explosion.</p> <p>More luminous HSSs could instead be tied to white dwarfs undergoing sustained nuclear burning. If the white dwarf’s photosphere expands, its effective temperature can decrease, shifting its emission toward longer wavelengths, potentially into the EUV, while leaving only a very soft X-ray signature detectable by Chandra.</p> <p>This possibility has profound implications for Type Ia supernovae. If a growing white dwarf grows toward the Chandrasekhar mass, it could eventually explode as a Type Ia supernova. Although these explosions are among the most important tools astronomers use to measure the expansion rate of the Universe, their progenitor systems remain an enduring mystery. HSSs could represent an important, previously overlooked stage in the evolution of some Type Ia supernova progenitors.</p> <p>HSSs may also help solve another long-standing mystery: what powers the ionization of gas between stars? Ionization occurs when energetic photons — particles of light — strip electrons from atoms. Hot, massive stars produce enough UV radiation to ionize hydrogen, but removing additional electrons from helium and heavier elements requires more energetic EUV photons—particularly difficult to explain in galaxies without an active galactic nucleus.</p> <p>A <a href="https://iopscience.iop.org/article/10.3847/1538-4357/ae057d">recent paper by Triani et al. (2025)</a> proposed that cool, highly luminous sources such as HSSs, emitting strongly in the EUV and very soft X-rays, could provide some of these missing ionizing photons. If so, HSSs may influence how the interstellar medium heats, cools, and forms stars.</p> <p>Regardless of their nature, HSSs offer a new glimpse into the unexplored EUV Universe, with potential implications for galactic gas ionization and the mystery of Type Ia supernova progenitors. For now, they remain a cosmic mystery—and an invitation to keep looking.</p> </div> <span><span>Chandra</span></span> <span><time datetime="2026-09-08T11:58:45-04:00" title="Tuesday, September 8, 2026 - 11:58">Tue, 09/08/2026 - 11:58</time> </span> <div class="node-taxonomy-container field--name-field-tags field--type-entity-reference field--label-above"> <h3 class="term-title"><i class="icon-bookmark"></i> Tags</h3> <ul class="taxonomy-terms"> <li class="taxonomy-term"><a href="http://chandra.harvard.edu/blog/taxonomy/term/25" hreflang="en">Unexpected</a></li> </ul> </div> <div class="node-taxonomy-container field--name-field-category field--type-entity-reference field--label-above"> <h3 class="term-title"><i class="icon-bookmark"></i> Category</h3> <ul class="taxonomy-terms"> <li class="taxonomy-term"><a href="http://chandra.harvard.edu/blog/taxonomy/term/9" hreflang="en">Normal Galaxies & Starburst Galaxies</a></li> </ul> </div> Tue, 08 Sep 2026 15:58:45 +0000 Chandra 972 at http://chandra.harvard.edu/blog Zombie Disks May Solve a Cosmic Mystery http://chandra.harvard.edu/blog/node/971 <span>Zombie Disks May Solve a Cosmic Mystery</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field-item"><p><meta charset="utf-8"></p> <p>The cosmos is full of surprises. When new classes of objects are discovered they can turn out to have more than one explanation. Some supernova explosions, for example, are triggered by the dramatic collapse of massive stars, while others involve the thermonuclear explosions of white dwarf stars. These two types of stars are remarkably different in size, mass, composition and density, but both can produce explosions that outshine entire galaxies. Another example is gamma ray bursts, which involve either the collapse of massive stars or the merger of two neutron stars.</p> <p>The origin of the <a href="http://chandra.harvard.edu/press/26_releases/press_090926.html">newly-discovered class of hypersoft X-ray sources</a> is unknown, but similar diversity may apply. One leading idea is that many of them involve matter falling onto the surfaces of white dwarfs. Once the white dwarfs reach a sufficient mass they may explode as Type Ia supernovas, addressing the mystery of what triggers these spectacular explosions. In other words, some of these hypersoft X-ray sources may represent the build up to Type Ias — a very important category of supernovas that lets astronomers measure the accelerating expansion of the Universe. However, this explanation struggles to explain the brightest of the hypersoft X-ray sources.</p> <p>Matter pulled away from companion stars by stellar-mass black holes, which typically have masses more than about ten times that of the Sun, offers a different explanation for these bright sources. As with white dwarfs, material pulled towards a black hole should be heated by friction to produce ultraviolet radiation. Because stellar-mass black holes, however, are much more massive and compact than white dwarfs, this process produces a larger amount of radiation.</p> <p>There is a major problem, however, with this simple interpretation of the hypersoft X-ray sources. When material in such systems approaches very close to a black hole, it should get so hot that it produces a lot of energetic X-rays — and astronomers are not seeing this with the hypersoft X-ray sources.</p> <div align="center"><a href="http://chandra.harvard.edu/blog/files/images/hypersoft_1080.jpg"><img src="http://chandra.harvard.edu/blog/files/images/hypersoft.jpg" alt="Artist's concept of a triple system containing a pair of black holes pulling material away from a Sun-like star." width="512" height="278" loading="lazy"></a><br> <div style="color:dimgrey;font-size:14px;line-height:14px;padding-top:5px;width:450px;"><strong>Artist's Concept:</strong> A triple system containing a pair of black holes pulling material away from a Sun-like star. Because little or no material falls onto the black holes, the disk is called a “zombie” disk. <br><span style="font-size:12px;line-height:14px;">Credit: Generated with Google Gemini (prompt by Galina Lipunova).</span><br><br> </div> </div> <p>An ingenious idea published earlier this year by Sergei Popov of the Sternberg Astronomical Institute in Russia, and Galina Lipunova of the Max Planck Institute for Radio Astronomy in Germany, may solve this problem. (The Research Note of the American Astronomical Society paper is <a href="https://iopscience.iop.org/article/10.3847/2515-5172/ae4d34/ampdf">here</a>, an expanded version is <a href="https://arxiv.org/abs/2603.08294">here</a> and a video from the AAS Author Journal Series is <a href="https://www.youtube.com/watch?v=qNX_uJvxiKs">here</a>.) They consider what happens in a triple system if a pair of closely orbiting black holes, rather than a single black hole, is pulling material away from a more distant companion star. The orbit of the two black holes should clear out a hole in the middle of the disk, as shown in their beautiful artist’s impression.</p> <p>Some people call these “dead” or “zombie” disks because hardly any material ends up falling into the black hole. Importantly for understanding the brightest hypersoft X-ray sources, the lack of a disk near the black holes prevents gas from getting hot enough to produce large amounts of energetic X-rays.</p> <p>Scientists will need more theoretical studies to determine how viable this idea is, including whether enough of these triple systems and zombie disks could form and survive to explain the brightest hypersoft X-ray sources. This work has the potential to not only explain some of the hypersoft X-ray sources, but also provide insight into the evolution of systems containing supermassive black holes orbiting each other and understanding the gravitational waves they can produce.</p> <p><strong>-Peter Edmonds, CXC</strong></p> </div> <span><span>Chandra</span></span> <span><time datetime="2026-09-08T10:54:57-04:00" title="Tuesday, September 8, 2026 - 10:54">Tue, 09/08/2026 - 10:54</time> </span> <div class="node-taxonomy-container field--name-field-tags field--type-entity-reference field--label-above"> <h3 class="term-title"><i class="icon-bookmark"></i> Tags</h3> <ul class="taxonomy-terms"> <li class="taxonomy-term"><a href="http://chandra.harvard.edu/blog/taxonomy/term/25" hreflang="en">Unexpected</a></li> </ul> </div> <div class="node-taxonomy-container field--name-field-category field--type-entity-reference field--label-above"> <h3 class="term-title"><i class="icon-bookmark"></i> Category</h3> <ul class="taxonomy-terms"> <li class="taxonomy-term"><a href="http://chandra.harvard.edu/blog/taxonomy/term/9" hreflang="en">Normal Galaxies & Starburst Galaxies</a></li> </ul> </div> Tue, 08 Sep 2026 14:54:57 +0000 Chandra 971 at http://chandra.harvard.edu/blog Time-lapse Photon Imaging: A New Way to Visualize Deep Chandra X-ray Observations http://chandra.harvard.edu/blog/node/970 <span>Time-lapse Photon Imaging: A New Way to Visualize Deep Chandra X-ray Observations</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field-item"><div style="float:left;margin-bottom:5px;margin-right:1em;text-align:center;width:303px;"><a href="http://chandra.harvard.edu/blog/files/images/jkastner_864.jpg"><img src="https://chandra.si.edu/blog/files/images/jkastner_303.jpg" alt="Head shot of Joel Kastner. He wearing a dark, collared shirt and smiling for the photo." width="303" height="259" loading="lazy"></a><br><em><span style="color:dimgrey;font-size:12px;">Joel Kastner</span></em><br><em><span style="color:dimgrey;font-size:12px;">(Credit: Joel Kastner, Rochester Institute of Technology)</span></em></div> <p><em>We welcome Joel Kastner, a professor at the Center for Imaging Science and School of Physics & Astronomy at the Rochester Institute of Technology, as our guest blogger. In this post, he describes how the final project of an RIT student, Tristan Liberace, for Kastner’s course in astronomical imaging resulted in a novel method to visualize long-duration Chandra observations — and a new view of the many (X-ray) faces of the active galaxy Centaurus A.</em></p> <p>This past May, I once again sat down to grade more than 50 final projects for the course ‘Fundamentals of Astronomical Imaging’ at Rochester Institute of Technology (RIT). Astro Imaging Fun, as our imaging science department staff and faculty prefer to call it, is a General Education course of my own design. Each spring I get to guide 50-60 RIT students, with majors ranging from graphic arts to business to computer science to engineering, through the wonderful world of imaging in astronomy across the electromagnetic spectrum, from radio to X-rays.</p> <p>Though (like many professors) I abhor assigning grades to student work, the final project images and image descriptions for Astro Imaging Fun are always, well, fun to see and read. It’s rewarding to see what the students have learned during the semester and how they’ve made use of that new knowledge, and there are always gems and pleasant surprises among the students’ image submissions.</p> <div style="float:right;margin-bottom:5px;margin-left:1em;text-align:center;width:303px;"><a href="http://chandra.harvard.edu/blog/files/images/liberace_864.jpg"><img src="https://chandra.si.edu/blog/files/images/liberace_303.jpg" alt="A head shot of Tristan Liberace. He is wearing a dark gray jakcet. Behind him, a sign on the wall reads, R I T, Rochester Institute of Technology." width="303" height="369" loading="lazy"></a><br><em><span style="color:dimgrey;font-size:12px;">Tristan Liberace (Credit: Tristan Liberace, RIT) </span></em></div> <p>This spring, one Astro Imaging Fun final project — from Tristan Liberace, a second-year electrical engineering major — really grabbed my attention. Tristan had generated a time-lapse video rendering of a set of deep Chandra X-ray Observatory exposures of the nearby, famous active galaxy Centaurus A (NGC 5128).</p> <p>As I watched his video, my jaw hit the floor: in all my years teaching this class, I’d never seen anything remotely like it. Indeed, I’d never seen anything remotely like Tristan’s time-lapse view of a Chandra observation in the entire, 25-plus-year lifetime of that storied NASA Great Observatory.</p> <p><br> </p> <p><strong>Timelapse of Centaurus A Chandra Data:</strong><br></p>  <div align="center"><video poster="http://chandra.harvard.edu/blog/files/images/tristan_liberace_chandra_cena_photon_timelapse_preview.jpg" controls width="525"><br> <source src="http://chandra.harvard.edu/blog/files/video/tristan_liberace_chandra_cena_photon_timelapse.mp4" type="video/mp4"> Your browser does not support the video tag. </video><br><span style="color:dimgrey;font-size:12px;">Credit: Tristan Liberace, Rochester Institute of Technology</span></div> <p></p><p>Over the semester, Tristan and the rest of the students taking Astro Imaging Fun had learned how astronomical sources — from stars to nebulae to phenomena in the early Universe — generate radiation across the electromagnetic spectrum, and how our quest to understand the natures of these sources and their emergent radiation drives the designs of astronomical imaging systems ranging from small telescopes and their cameras to state-of-the-art facilities like Hubble, Webb, Chandra, Gemini, the Very Large Telescope, and the Atacama Millimeter-submillimeter Array.</p> <p>Through lectures and lab exercises, we broke down the detailed anatomies of these imaging systems, and we explored the myriad ways astronomers (professional and amateur alike) render and scientifically interpret the resulting multiwavelength images. The course is capped by a final project intended to tie things together. Each student selects an astronomical object (typically, a nebula or galaxy) that has captured their interest and then combs the public image archives of major space- and ground-based astronomical observing facilities for images of the object. The student uses these archival image data to generate an original view of their chosen object, and they describe how they generated their image and what it reveals about the object.</p> <p>Tristan’s work went way above and beyond. As he himself described it, in his final project report (here lightly edited):</p> <p><em>This video was produced by compiling six different observing sessions (exposures) from the Chandra X-ray Observatory from 2007, all targeting Cen A, and overlaying them on top of each other, with the precise time of each event detected by its Advanced CCD Imaging Spectrometer (ACIS) instrument taken into account. This effectively results in a time-lapse rendering of the X-rays that were detected by ACIS over the nearly 2-day timespan of the six Cen A observations. Each photon hitting the sensor during an individual 3-second CCD exposure is visualized in the video with a ‘splash’ effect, briefly turning the surrounding pixels white, so as to emphasize for the viewer that a photon has struck the CCD. The accumulating image is then rendered as a heat map of pixel photon counts: as more photons land in a given pixel, that pixel becomes ‘hotter’, with the number of accumulated photons represented by a gradient from red to yellow in the image.</em></p> <p>“The result of this process is a composite of over 150 hours of imaging data from Chandra compressed into 90 seconds, producing a majestic representation of X-rays from Centaurus A,” Tristan concludes. Indeed, in viewing the short video, one certainly sees that “majestic representation” — and much more.</p> <p>As the video begins, only the Cen A core and the brightest surrounding X-ray point sources are apparent. Because the galaxy’s growing supermassive black hole (also known as an active galactic nucleus) emits such an intense stream of X-rays, the pixels in the center of the detector accumulate photon counts much faster than the rest of the field. This causes the central region to “heat up” and become visible much sooner as these high-rate regions accumulate photons far more rapidly than the fainter surrounding space. Then, Cen A’s beadlike jet, protruding out to the upper left, starts to emerge from the blackness. The tremendously bright Cen A core — the galaxy’s active nucleus — grows slowly and continuously, as photons that are scattered into the wings of Chandra’s point spread function, or PSF, splash down into ACIS. (The PSF describes how much a point-like source of light, in this case X-rays, is enlarged by the various elements of an imaging system, thus spreading the source out in the resulting image.)</p> <p>As the video proceeds, increasingly faint point sources appear, and the Cen A jet begins to take on a searchlight appearance. X-ray background photons also steadily arrive, but — because these photons are spread uniformly over the entire CCD sensor area — this background remains subdued relative to the Cen A core/jet system and its surrounding flotilla of point sources.</p> <p>About halfway through the video, a horizontal streak begins to appear. This is an ACIS “readout streak”, the result of X-rays from Cen A’s intense core striking pixels even as photon-generated charge is sped down the rows of the CCD during its few thousandths of a second readout period. This streak is soon joined by a diagonal readout streak from an exposure obtained at a different orientation angle (rotation) of Chandra’s view of the sky, and then by several more streaks, each at a slightly different angle. By the end of the video, the PSF of the Cen A core has reached its full bloat, the jet is seen to stretch halfway across the image, and X-ray point sources from exotic binary systems in NGC 5128 are sprinkled all across the otherwise X-ray-invisible host galaxy. As Tristan put it:</p> <p>In the final image, a jet of matter can be seen spewing out from the energy-dense center of the galaxy. This jet is caused by the supermassive black hole in the center of the galaxy, which is estimated to have a mass of 55 million solar masses. The highly energetic environment surrounding the black hole flings particles at relativistic velocities, which then collide with surrounding gases and produce the X-ray emission detected by Chandra.</p> <p>Each time I watch Tristan’s video, I find myself rewinding and watching it again. And his video makes me want to see other deep Chandra X-ray exposures rendered in the same, time-lapse fashion that Tristan has so creatively and ingeniously engineered for Cen A. By animating individual photon events, Tristan has given us a more intuitive sense of how a telescope like Chandra collects data over time and then passes along this information to us. Ultimately, this visualization approach reminds us that astronomical data isn't static—it’s a living record of time, energy, and light. That’s why seeing a 2-day Chandra X-ray observation materializing in front of your eyes, photon by photon — over the span of just 90 seconds — is so profoundly moving.</p> </div> <span><span>Chandra</span></span> <span><time datetime="2026-09-02T15:00:09-04:00" title="Wednesday, September 2, 2026 - 15:00">Wed, 09/02/2026 - 15:00</time> </span> <div class="node-taxonomy-container field--name-field-category field--type-entity-reference field--label-above"> <h3 class="term-title"><i class="icon-bookmark"></i> Category</h3> <ul class="taxonomy-terms"> <li class="taxonomy-term"><a href="http://chandra.harvard.edu/blog/taxonomy/term/11" hreflang="en">Cosmology/Deep Field</a></li> </ul> </div> Wed, 02 Sep 2026 19:00:09 +0000 Chandra 970 at http://chandra.harvard.edu/blog Galactic Gems Glisten in New Gallery From NASA's Chandra http://chandra.harvard.edu/blog/node/969 <span>Galactic Gems Glisten in New Gallery From NASA's Chandra</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field-item"><p><meta charset="utf-8"></p> <div style="margin-bottom:20px;text-align:center;"><a href="http://chandra.harvard.edu/photo/2026/galaxies/"><img src="http://chandra.harvard.edu/photo/2026/galaxies/galaxies_525.jpg" alt="Images of sixteen galaxies presented in four rows and four columns. First row labels are: NGC 1672, II Zw 096, M33, and NGC 4258. Second row labels are: NGC 1569, M90, Centaurus A, and M104. Third row labels are: Arp 143, NGC 4725, NGC 1385, and NGC 660. Fourth row labels are: M82, NGC 3256, NGC 3938, and NGC 4631." width="525" height="382" loading="lazy"></a><br><a href="http://chandra.harvard.edu/photo/2026/galaxies/"><span style="color:dimgrey;">Galaxy Gallery</span></a><br><a href="http://chandra.harvard.edu/photo/2026/galaxies/"><span style="color:dimgrey;font-size:14px;text-decoration:underline;">More images and information</span></a><br><span style="color:dimgrey;font-size:10px;line-height:10px;">Credit: NASA/CXC/SAO</span></div> <p style="margin-bottom:8.0pt;"><span style="font-size:12.0pt;line-height:115%;" lang="EN">Galaxies are like cosmic gems, each with characteristics including size and shape that make them distinct. A new gallery released today from NASA’s Chandra X-ray Observatory and other telescopes displays a collection of galactic images that showcase this variety.</span></p> <p style="margin-bottom:8.0pt;"><span style="font-size:12.0pt;line-height:115%;" lang="EN">Astronomers put galaxies into three main categories: spirals like our own Milky Way with arms emanating from their cores, ellipticals that are older and likely the results of mergers, and irregulars that can encompass a wide range of galactic phenomena.</span></p> <p><span style="font-family:"Arial",sans-serif;font-size:12.0pt;line-height:115%;" lang="EN">Just as gems reveal the history of Earth through how they were forged over billions of years, these galactic gems are a way to study Earth’s place in our home galaxy of the Milky Way. By looking outward to other galaxies, we learn more about our own – including clues to its past and future</span>.</p> <div align="center"><a href="http://chandra.harvard.edu/photo/2026/galaxies/more.html"><img src="http://chandra.harvard.edu/photo/2026/galaxies/galaxies_labeled_525.jpg" alt="A labeled version of the main image showing sixteen images, presented in four rows and four columns. First row labels are: NGC 1672, II Zw 096, M33, and NGC 4258. Second row labels are: NGC 1569, M90, Centaurus A, and M104. Third row labels are: Arp 143, NGC 4725, NGC 1385, and NGC 660. Fourth row labels are: M82, NGC 3256, NGC 3938, and NGC 4631." width="525" height="382" loading="lazy"></a><br> <div style="color:dimgrey;font-size:12px;line-height:12px;padding-top:10px;width:400px;"><strong>Galaxy Gallery, labeled.</strong> Credit: NASA/CXC/SAO<br><br> </div> </div> <p style="margin-bottom:8.0pt;"><span style="font-size:12.0pt;line-height:115%;" lang="EN">There are 16 new images in this galactic gallery. Each one contains X-ray data from Chandra that has been collected across Chandra’s decades in space. This high-energy data has been combined with data from telescopes such as NASA’s James Webb and Hubble Space Telescopes, IXPE (Imaging X-ray Polarimetry Explorer), Neil Gehrels Swift Observatory, NuSTAR (Nuclear Spectroscopic Telescope Array), and others both on the ground and in space. </span></p> <p><span style="font-family:"Arial",sans-serif;font-size:12.0pt;line-height:115%;" lang="EN">X-rays are critical for the study of galaxies, revealing unique and important information about these cosmic building blocks. For example, Chandra exposes gas that has been superheated to millions of degrees by winds from massive stars, the outflows from supermassive black holes, and the debris from exploded stars. These are key sources of elements in our bodies, in the air we breathe, and the planet we live on. Chandra also sees some of the hottest and most energetic galactic phenomena in the universe, forming a more complete picture of how galaxies live, interact, and evolve when combined with data from other types of light and telescopes</span>.</p> <p><strong>Spiral and star-forming engines</strong><br><span style="background-color:white;font-family:"Arial",sans-serif;font-size:12.0pt;line-height:115%;" lang="EN">Face-on spiral galaxies like Messier 33 and NGC 3938 offer unobstructed views of places where energetic pairs of stars and cosmic explosions live along spiral arms. Barred spirals like NGC 1672 and NGC 1385 show how central bar-shaped collections of stars, gas, and dust funnel fuel inward to ignite bursts of star formation. NGC 4725 reveals how star formation can be triggered by a previous collision with another galaxy. Meanwhile, edge-on views of NGC 4631 (the Whale Galaxy) and the starburst Messier 82 (the Cigar Galaxy) showcase giant halos and superwinds of million-degree gas driven thousands of light-years into space by intense explosions of stars, enriching surrounding intergalactic space with vital elements</span>.</p> <p><strong>Active galactic nuclei, black hole outflows</strong><br><span style="background-color:white;font-family:"Arial",sans-serif;font-size:12.0pt;line-height:115%;" lang="EN">Powerful, growing black holes in the cores of their host galaxies, known as active galactic nuclei, send energy outward in outbursts and jets that impact entire galaxies. In Centaurus A, Chandra and IXPE data expose a high-energy particle jet blasting tens of thousands of light-years into space from its central engine. In Messier 106, jets from the supermassive black hole heat surrounding gas to create spiral arms that are different from those typically found in spiral galaxies. </span><span style="font-family:"Arial",sans-serif;font-size:12.0pt;line-height:115%;" lang="EN">Meanwhile, the iconic Sombrero Galaxy (Messier 104) highlights a supermassive black hole embedded in a colossal stellar bulge, where Chandra’s X-rays map a diffuse halo of million-degree gas and hot stellar remnants surrounding its sweeping dust lanes</span>.</p> <p><strong>Collisions, mergers, cosmic disruptions</strong><br><span style="background-color:white;font-family:"Arial",sans-serif;font-size:12.0pt;line-height:115%;" lang="EN">The gallery also showcases galaxies undergoing extreme gravitational transformations. A direct impact in Arp 143 acts like a cosmic bullseye, creating an expanding ring galaxy and triggering waves of star birth. Violent mergers, such as NGC 3256 and the dust-shrouded starburst II Zw 096, reveal the kind of chaotic galaxy collisions that dominated the early universe and offer a preview of the Milky Way’s distant future merger with nearby galaxy Andromeda. NGC 1569 acts as a local laboratory for studying early universe starbursts, NGC 660 showcases a rare "polar ring" galaxy where a ring of stars orbits over its poles, and Messier 90 shows a spiral galaxy plowing through the Virgo Cluster, having its star-forming gas violently stripped away</span>.</p> <p>NASA's Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.</p> </div> <span><span>Chandra</span></span> <span><time datetime="2026-08-20T15:50:23-04:00" title="Thursday, August 20, 2026 - 15:50">Thu, 08/20/2026 - 15:50</time> </span> <div class="node-taxonomy-container field--name-field-category field--type-entity-reference field--label-above"> <h3 class="term-title"><i class="icon-bookmark"></i> Category</h3> <ul class="taxonomy-terms"> <li class="taxonomy-term"><a href="http://chandra.harvard.edu/blog/taxonomy/term/9" hreflang="en">Normal Galaxies & Starburst Galaxies</a></li> </ul> </div> Thu, 20 Aug 2026 19:50:23 +0000 Chandra 969 at http://chandra.harvard.edu/blog NASA Telescopes Create Colorful 'Craft' From Nearby Nebula http://chandra.harvard.edu/blog/node/968 <span>NASA Telescopes Create Colorful 'Craft' From Nearby Nebula</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field-item"><div style="margin-bottom:20px;text-align:center;"><a href="http://chandra.harvard.edu/photo/2026/30dor/"><img src="http://chandra.harvard.edu/photo/2026/30dor/30dor_525.jpg" alt="A layered image of the Tarantula Nebula." width="525" height="523" loading="lazy"></a><br><a href="http://chandra.harvard.edu/photo/2026/30dor/"><span style="color:dimgrey;">Tarantula Nebula / 30 Doradus</span></a><br><a href="http://chandra.harvard.edu/photo/2026/30dor/"><span style="color:dimgrey;font-size:14px;text-decoration:underline;">More images, videos, and information</span></a><br><span style="color:dimgrey;font-size:12px;">Credit: X-ray: NASA/CXC/Ohio State Univ./J. Rodriguez et al; Infrared: NASA/ESA/CSA/STScI; Optical: NASA/ESA/STScI; Image Processing: NASA/CXC/SAO/P. Edmonds</span></div> <p>Like a collage made of layered sheets of colored cellophane, a vibrant new image layers observations of a famous star-forming nebula from NASA space telescopes. The resulting cosmic “craft” reveals new details about the star formation region known as 30 Doradus, or the Tarantula Nebula.</p> <p>Located in the Large Magellanic Cloud, a small neighbor galaxy to the Milky Way about 160,000 light-years from Earth, the Tarantula has thousands of young stars embedded in a vibrant honeycomb-like structure of gas and dust.</p> <p>The new composite image contains X-rays from NASA’s Chandra X-ray Observatory, which has repeatedly observed the Tarantula Nebula over the course of its mission, in the layer that appears in blue. The X-ray data reveals gas blown away by winds from the surfaces of young, massive stars and heated to millions of degrees by shock waves, like sonic booms from supersonic jets.</p> <p>The red represents infrared data from NASA’s James Webb Space Telescope showing thousands of young stars, plus swaths of cool dust that will provide the ingredients to form new stars and planets. Optical data in the green layer from NASA’s Hubble Space Telescope uncovers hydrogen gas that is warmer than seen with Webb, as well as some individual stars through the nebula.</p> <p>The composite image shows the full Hubble and Webb images of this region, as well as a large section of the Chandra image, all recently published in a <a href="https://iopscience.iop.org/article/10.3847/1538-4357/ae3c7a">research paper in the Astrophysical Journal</a>. In some regions the blue Chandra layer stands alone, and in others it combines with either the red Webb data or the green Hubble data. In the middle region all three images overlap to provide a holistic view in red, orange, yellow, green, and blue.</p> <p><strong>How the Telescope Data is Combined:</strong><br></p>  <div align="center"><video poster="http://chandra.harvard.edu/photo/2026/30dor/30dor_wavelengths_preview.jpg" controls width="525"><br> <source src="http://chandra.harvard.edu/photo/2026/30dor/30dor_wavelengths.mp4" type="video/mp4"><br> Your browser does not support the video tag.<br> </video><br> </div> <p>Previously, astronomers had studied the amount and the impact of energy produced by winds from young, massive stars in the Tarantula Nebula. Scientists expect that much of this energy should heat gas so that it produces X-rays. However, the research paper shows that there is much less X-ray-emitting gas in the nebula than expected. This led researchers to ask: Where has this energy gone and what tamed the Tarantula Nebula?</p> <p>By studying the data from Chandra, Hubble, and Webb, combined with data from NASA’s retired Spitzer Space Telescope, the team concluded the Tarantula may be losing energy from several sources.</p> <p>First, up to half of the hot gas is leaking through the shell walls of the gas and dust structures and escaping the nebula. Next, there is stirring and mixing between the cold gas near the shell walls and some of the hot gas, lowering the overall temperature of the gas. Finally, comparisons with computer simulations suggest the Tarantula may be losing energy through conduction. This involves direct physical contact between hot and cooler material, like with a frying pan on a burner, causing the hot and cooler material to equalize in temperature. In the case of the Tarantula Nebula, the hot gas would be conducting heat by being in direct contact with the cooler gas in the shells, especially in the densest regions. This scenario does not necessarily involve mixing the hot and cooler gas.</p> <p>The combination of these three channels for losing large amounts of energy leads to this colorful and complex display revealed by NASA's telescopes working together.</p> <div align="center"><a href="http://chandra.harvard.edu/photo/2026/30dor/oconnor_decam_864.jpg"><img src="http://chandra.harvard.edu/photo/2026/30dor/30dor_crop_525.jpg" alt="Dark Energy Camera image of supernova SN 2026gzf" width="525" height="463" loading="lazy"></a><br> <div style="color:dimgrey;font-size:13px;line-height:14px;padding-top:10px;width:400px;"><strong>Tarantula Nebula / 30 Doradus, cropped version.</strong><br>Credit: X-ray: NASA/CXC/Ohio State Univ./J. Rodriguez et al; Infrared: NASA/ESA/CSA/STScI; Optical: NASA/ESA/STScI; Image Processing: NASA/CXC/SAO/P. Edmonds<br><br> </div> </div> <p>The <a href="https://iopscience.iop.org/article/10.3847/1538-4357/ae3c7a">paper describing these results</a> was led by Jennifer Rodriguez of The Ohio State University in Columbus. Additional authors on the paper include Laura Lopez, Ohio State; Lachlan Lancaster, Columbia University in New York City; Anna Rosen, San Diego State University; Omnaraynai Nayak, Space Telescope Science Institute in Baltimore; Sebastian Lopez, Ohio State; Tyler Holland-Ashford, NASA’s Goddard Space Flight Center in Greenbelt, Maryland; and Trinity Webb, Ohio State.</p> <p>NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.</p> </div> <span><span>Chandra</span></span> <span><time datetime="2026-08-11T11:50:25-04:00" title="Tuesday, August 11, 2026 - 11:50">Tue, 08/11/2026 - 11:50</time> </span> <div class="node-taxonomy-container field--name-field-category field--type-entity-reference field--label-above"> <h3 class="term-title"><i class="icon-bookmark"></i> Category</h3> <ul class="taxonomy-terms"> <li class="taxonomy-term"><a href="http://chandra.harvard.edu/blog/index.html/taxonomy/term/3" hreflang="en">Normal Stars & Star Clusters</a></li> </ul> </div> Tue, 11 Aug 2026 15:50:25 +0000 Chandra 968 at http://chandra.harvard.edu/blog Rare Stellar Explosion Gives Astronomers a Front-Row Seat to a Massive Star's Death http://chandra.harvard.edu/blog/node/967 <span>Rare Stellar Explosion Gives Astronomers a Front-Row Seat to a Massive Star's Death</span> <div class="field field--name-body field--type-text-with-summary field--label-hidden field-item"><p>Today astronomers have announced that they caught a massive star’s death from the first explosive moment. The supernova may represent a new way for stars to end their lives. Press releases based on two papers just published in The Astrophysical Journal Letters describe the extensive set of observatories they used to study the supernova, including NOIRLab telescopes, NASA’s Chandra X-ray Observatory and the National Radio Astronomy Observatory’s Very Large Array. In particular, a <a href="http://chandra.harvard.edu/press/26_releases/press_080526.html">press release</a> from Carnegie Mellon University (CMU) highlights work by Brendan O’Connor who led <a href="https://iopscience.iop.org/article/10.3847/2041-8213/ae84ba">one of these papers</a>. We are delighted to welcome Brendan as a guest blogger to describe Chandra’s important role in this work.</p> <div style="float:left;margin-bottom:5px;margin-right:1em;text-align:center;width:303px;"><a href="http://chandra.harvard.edu/blog/files/images/oconnor_540.jpg"><img src="https://chandra.si.edu/blog/files/images/oconnor_303.jpg" alt="Brendan O'Connor is posed for this photo, leaning against a wall on his left side while wearing a red and gray plaid, flannel shirt." width="303" height="420" loading="lazy"></a><br><em><span style="color:dimgrey;font-size:12px;">Brendan O'Connor (Credit: Brendan O'Connor)</span></em></div> <p><em>O’Connor is a McWilliams Fellow in the McWilliams Center for Cosmology and Astrophysics at CMU, where he studies cosmic explosions. His research concentrates on time-domain and transient astrophysics with a focus on the formation and evolution of high-energy transients and their progenitors. He uses a range of optical, infrared, and X-ray observatories to investigate these phenomena across the electromagnetic spectrum and is an avid user of NASA’s Chandra X-ray Observatory. He received his PhD from The George Washington University in 2023 under the supervision of Dr. Chryssa Kouveliotou, Dr. Eleonora Troja, and Dr. Brad Cenko. He will soon move to the Joint Space-Science Institute at the University of Maryland, College Park and NASA Goddard Space Flight Center as a Neil Gehrels Prize Postdoctoral Fellow.</em></p> <p> </p> <p><strong>Chandra Probes the Aftermath of a Rare X-ray Flash</strong><br><em>Brendan O’Connor</em></p> <p>On March 21, 2026, China’s Einstein Probe X-ray satellite detected a brief flash of X-rays from a galaxy about 500 million light-years away. Multiple groups of astronomers, including one that I was privileged to lead, have interpreted the flash, designated EP260321a, as a “shock breakout”. This type of flash is produced by the moment when the shock wave — similar to a supersonic plane’s sonic boom — from an exploding star reaches the star’s surface, and releases the supernova’s first observable burst of light. Astronomers kept observing this supernova (now called SN 2026gzf) and watched as it continued to get brighter., They now think SN 2026gzf belongs to the “broad-lined Type Ic” class of supernovas (“broad lined” references the width in the light spectrum and indicates material is moving very fast, at almost 10% of the speed of light) . These energetic explosions arise from massive stars that have lost their outer hydrogen and helium layers, and they are the same class of supernova seen accompanying many gamma-ray bursts (GRBs) that last longer than two seconds.</p> <div align="center"><a href="http://chandra.harvard.edu/blog/files/images/oconnor_decam_864.jpg"><img src="http://chandra.harvard.edu/blog/files/images/oconnor_decam_525.jpg" alt="Dark Energy Camera image of supernova SN 2026gzf" width="525" height="525" loading="lazy"></a><br> <div style="color:dimgrey;font-size:13px;line-height:14px;width:400px;"><strong>DECam Image of Supernova SN 2026gzf.</strong><br><strong>Caption:</strong> An image taken on March 25th, 2026 of supernova SN 2026gzf, which appears as a bright blue point source in the upper right corner of the host galaxy. The image was taken with the Dark Energy Camera (DECam), mounted on the NSF Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory in Chile.<br><strong>Credit:</strong> CTIO/NOIRLab/DOE/NSF/AURA; Image Processing: D. de Martin & M. Zamani (NSF NOIRLab)<br><br> </div> </div> <p>The resemblance raised a crucial question: had the stellar explosion producing SN 2026gzf launched a powerful jet even though astronomers didn’t detect a GRB ? A GRB occurs when a narrow jet of material moving at relativistic speeds — that is, close to the speed of light — successfully escapes the collapsing star. Astronomers may miss the very first gamma rays if the burst is faint or if the jet is not pointed toward Earth, but the jet should continue to reveal itself through a longer-lived afterglow. This afterglow is produced as the jet collides with particles surrounding the star, generating radiation that can remain visible in X-rays for days, weeks or even months depending on the density of the environment and the total energy of the jet.</p> <p>NASA’s Chandra X-ray Observatory provided the critical test of whether such a jet had escaped. I initiated Chandra observations of SN 2026gzf to search for the predicted fading X-ray afterglow that is expected from a successful jet. Chandra’s exceptional sensitivity and sharp imaging allowed the team to search for very faint X-ray emission precisely at the location of the supernova. Although we did not detect an X-ray source, as reported in the newly published paper I led, we learned valuable information about the explosion. Due to the relatively close proximity of the explosion to Earth, the observations were sensitive enough that they would have detected nearly every known GRB X-ray afterglow.</p> <p>The Chandra data therefore ruled out the typical bright X-ray afterglow produced by a successful GRB jet. The data also placed strong constraints on jets that might have been weaker or directed away from Earth, essentially ruling out those options. Instead, our results show that SN 2026gzf did not produce a normal, powerful relativistic jet. Rather, the star may have launched a weaker outflow that stalled inside the star before it could break free. EP260321a/SN 2026gzf is the first high-energy flash associated with a broad-lined Type Ic supernova that did not have a relativistic outflow, showing that stripped stars can explode in more ways than previously thought.</p> </div> <span><span>Chandra</span></span> <span><time datetime="2026-08-03T11:05:25-04:00" title="Monday, August 3, 2026 - 11:05">Mon, 08/03/2026 - 11:05</time> </span> <div class="node-taxonomy-container field--name-field-category field--type-entity-reference field--label-above"> <h3 class="term-title"><i class="icon-bookmark"></i> Category</h3> <ul class="taxonomy-terms"> <li class="taxonomy-term"><a href="http://chandra.harvard.edu/blog/taxonomy/term/5" hreflang="en">Supernovas & Supernova Remnants</a></li> </ul> </div> Mon, 03 Aug 2026 15:05:25 +0000 Chandra 967 at http://chandra.harvard.edu/blog