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A team of European astronomers has used two of the most powerful astronomical facilities available, NASA's Hubble Space Telescope and the European Southern Observatory's (ESO) Very Large Telescope (VLT) at Cerro Paranal, to find a bright quasar without a massive host galaxy. Quasars are powerful and typically very distant sources of prodigious amounts of radiation. They are commonly associated with galaxies containing an active central black hole. The team confidently concludes that the quasar on the left, HE0450-2958 (in the center, distance about 5 billion light-years) does not have a massive host galaxy. The quasar HE1239-2426 to the right (at a distance of 1.5 billion light-years), has a normal host galaxy which displays large spiral arms.

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    • By NASA
      An artist’s concept of a supermassive black hole, a surrounding disk of material falling towards the black hole and a jet containing particles moving away at close to the speed of light. This black hole represents a recently-discovered quasar powered by a black hole. New Chandra observations indicate that the black hole is growing at a rate that exceeds the usual limit for black holes, called the Eddington Limit. Credit: NASA/CXC/SAO/M. WeissX-ray: NASA/CXC/INAF-Brera/L. Ighina et al.; Illustration: NASA/CXC/SAO/M. Weiss; Image Processing: NASA/CXC/SAO/N. Wolk A black hole is growing at one of the fastest rates ever recorded, according to a team of astronomers. This discovery from NASA’s Chandra X-ray Observatory may help explain how some black holes can reach enormous masses relatively quickly after the big bang.
      The black hole weighs about a billion times the mass of the Sun and is located about 12.8 billion light-years from Earth, meaning that astronomers are seeing it only 920 million years after the universe began. It is producing more X-rays than any other black hole seen in the first billion years of the universe.
      The black hole is powering what scientists call a quasar, an extremely bright object that outshines entire galaxies. The power source of this glowing monster is large amounts of matter funneling around and entering the black hole.
      While the same team discovered it two years ago, it took observations from Chandra in 2023 to discover what sets this quasar, RACS J0320-35, apart. The X-ray data reveal that this black hole appears to be growing at a rate that exceeds the normal limit for these objects.
      “It was a bit shocking to see this black hole growing by leaps and bounds,” said Luca Ighina of the Center for Astrophysics | Harvard & Smithsonian in Cambridge, Massachusetts, who led the study.
      When matter is pulled toward a black hole it is heated and produces intense radiation over a broad spectrum, including X-rays and optical light. This radiation creates pressure on the infalling material. When the rate of infalling matter reaches a critical value, the radiation pressure balances the black hole’s gravity, and matter cannot normally fall inwards any more rapidly. That maximum is referred to as the Eddington limit.
      Scientists think that black holes growing more slowly than the Eddington limit need to be born with masses of about 10,000 Suns or more so they can reach a billion solar masses within a billion years after the big bang — as has been observed in RACS J0320-35. A black hole with such a high birth mass could directly result from an exotic process: the collapse of a huge cloud of dense gas containing unusually low amounts of elements heavier than helium, conditions that may be extremely rare.
      If RACS J0320-35 is indeed growing at a high rate — estimated at 2.4 times the Eddington limit — and has done so for a sustained amount of time, its black hole could have started out in a more conventional way, with a mass less than a hundred Suns, caused by the implosion of a massive star.
      “By knowing the mass of the black hole and working out how quickly it’s growing, we’re able to work backward to estimate how massive it could have been at birth,” said co-author Alberto Moretti of INAF-Osservatorio Astronomico di Brera in Italy. “With this calculation we can now test different ideas on how black holes are born.”
      To figure out how fast this black hole is growing (between 300 and 3,000 Suns per year), the researchers compared theoretical models with the X-ray signature, or spectrum, from Chandra, which gives the amounts of X-rays at different energies. They found the Chandra spectrum closely matched what they expected from models of a black hole growing faster than the Eddington limit. Data from optical and infrared light also supports the interpretation that this black hole is packing on weight faster than the Eddington limit allows.
      “How did the universe create the first generation of black holes?” said co-author Thomas of Connor, also of the Center for Astrophysics. “This remains one of the biggest questions in astrophysics and this one object is helping us chase down the answer.”
      Another scientific mystery addressed by this result concerns the cause of jets of particles that move away from some black holes at close to the speed of light, as seen in RACS J0320-35. Jets like this are rare for quasars, which may mean that the rapid rate of growth of the black hole is somehow contributing to the creation of these jets.
      The quasar was previously discovered as part of a radio telescope survey using the Australian Square Kilometer Array Pathfinder, combined with optical data from the Dark Energy Camera, an instrument mounted on the Victor M. Blanco 4-meter Telescope at the Cerro Tololo Inter-American Observatory in Chile. The U.S. National Science Foundation National Optical-Infrared Astronomy Research Laboratory’s Gemini-South Telescope on Cerro Pachon, Chile was used to obtain the accurate distance of RACS J0320-35.
      A paper describing these results has been accepted for publication in The Astrophysical Journal and is available here.
      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, and flight operations from Burlington, Massachusetts.
      Read more from NASA’s Chandra X-ray Observatory Learn more about the Chandra X-ray Observatory and its mission here:
      https://www.nasa.gov/chandra
      https://chandra.si.edu
      Visual Description
      This release features a quasar located 12.8 billion light-years from Earth, presented as an artist’s illustration and an X-ray image from NASA’s Chandra X-ray Observatory.
      In the artist’s illustration, the quasar, RACS J0320-35, sits at our upper left, filling the left side of the image. It resembles a spiraling, motion-blurred disk of orange, red, and yellow streaks. At the center of the disk, surrounded by a glowing, sparking, brilliant yellow light, is a black egg shape. This is a black hole, one of the fastest-growing black holes ever detected. The black hole is also shown in a small Chandra X-ray image inset at our upper right. In that depiction, the black hole appears as a white dot with an outer ring of neon purple.
      The artist’s illustration also highlights a jet of particles blasting away from the black hole at the center of the quasar. The streaked silver beam starts at the core of the distant quasar, near our upper left, and shoots down toward our lower right. The blurry beam of energetic particles appears to widen as it draws closer and exits the image.
      News Media Contact
      Megan Watzke
      Chandra X-ray Center
      Cambridge, Mass.
      617-496-7998
      mwatzke@cfa.harvard.edu
      Corinne Beckinger
      Marshall Space Flight Center, Huntsville, Alabama
      256-544-0034
      corinne.m.beckinger@nasa.gov
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      Last Updated Sep 18, 2025 EditorLee MohonContactCorinne M. Beckingercorinne.m.beckinger@nasa.govLocationMarshall Space Flight Center Related Terms
      Chandra X-Ray Observatory Astrophysics Black Holes Galaxies, Stars, & Black Holes Galaxies, Stars, & Black Holes Research Marshall Astrophysics Marshall Space Flight Center Quasars Science & Research Supermassive Black Holes The Universe Explore More
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    • By NASA
      6 min read
      NASA’s IMAP Mission to Study Boundaries of Our Home in Space
      Summary
      NASA’s new Interstellar Mapping and Acceleration Probe, or IMAP, will launch no earlier than Tuesday, Sept. 23 to study the heliosphere, a giant shield created by the Sun. The mission will chart the heliosphere’s boundaries to help us better understand the protection it offers life on Earth and how it changes with the Sun’s activity. The IMAP mission will also provide near real-time measurements of the solar wind, data that can be used to improve models predicting the impacts of space weather ranging from power-line disruptions to loss of satellites, to the health of voyaging astronauts. Space is a dangerous place — one that NASA continues to explore for the benefit of all. It’s filled with radiation and high-energy particles that can damage DNA and circuit boards alike. Yet life endures in our solar system in part because of the heliosphere, a giant bubble created by the Sun that extends far beyond Neptune’s orbit.
      With NASA’s new Interstellar Mapping and Acceleration Probe, or IMAP, launching no earlier than Tuesday, Sept. 23, humanity is set to get a better look at the heliosphere than ever before. The mission will chart the boundaries of the heliosphere to help us better understand the protection it offers and how it changes with the Sun’s activity. The IMAP mission will also provide near real-time measurements of space weather conditions essential for the Artemis campaign and deep space travel. 
      “With IMAP, we’ll push forward the boundaries of knowledge and understanding of our place not only in the solar system, but our place in the galaxy as a whole,” said Patrick Koehn, IMAP program scientist at NASA Headquarters in Washington. “As humanity expands and explores beyond Earth, missions like IMAP will add new pieces of the space weather puzzle that fills the space between Parker Solar Probe at the Sun and the Voyagers beyond the heliopause.”
      Download this video from NASA’s Scientific Visualization Studio.
      Domain of Sun
      The heliosphere is created by the constant outflow of material and magnetic fields from the Sun called the solar wind. As the solar system moves through the Milky Way, the solar wind’s interaction with interstellar material carves out the bubble of the heliosphere. Studying the heliosphere helps scientists understand our home in space and how it came to be habitable.
      As a modern-day celestial cartographer, IMAP will map the boundary of our heliosphere and study how the heliosphere interacts with the local galactic neighborhood beyond. It will chart the vast range of particles, dust, ultraviolet light, and magnetic fields in interplanetary space, to investigate the energization of charged particles from the Sun and their interaction with interstellar space.
      The IMAP mission builds on NASA’s Voyager and IBEX (Interstellar Boundary Explorer) missions. In 2012 and 2018, the twin Voyager spacecraft became the first human-made objects to cross the heliosphere’s boundary and send back measurements from interstellar space. It gave scientists a snapshot of what the boundary looked like and where it was in two specific locations. While IBEX has been mapping the heliosphere, it has left many questions unanswered. With 30 times higher resolution and faster imaging, IMAP will help fill in the unknowns about the heliosphere.
      Energetic neutral atoms: atomic messengers from our heliosphere’s edge
      Of IMAP’s 10 instruments, three will investigate the boundaries of the heliosphere by collecting energetic neutral atoms, or ENAs. Many ENAs originate as positively charged particles released by the Sun but after racing across the solar system, these particles run into particles in interstellar space. In this collision, some of those positively charged particles become neutral, and an energetic neutral atom is born. The interaction also redirects the new ENAs, and some ricochet back toward the Sun.
      Charged particles are forced to follow magnetic field lines, but ENAs travel in a straight line, unaffected by the twists, turns, and turbulences in the magnetic fields that permeate space and shape the boundary of the heliosphere. This means scientists can track where these atomic messengers came from and study distant regions of space from afar. The IMAP mission will use the ENAs it collects near Earth to trace back their origins and construct maps of the boundaries of the heliosphere, which would otherwise be invisible from such a distance.
      “With its comprehensive state-of-the-art suite of instruments, IMAP will advance our understanding of two fundamental questions of how particles are energized and transported throughout the heliosphere and how the heliosphere itself interacts with our galaxy,” said Shri Kanekal, IMAP mission scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
      The IMAP mission will study the heliosphere, our home in space. NASA/Princeton University/Patrick McPike Space weather: monitoring solar wind
      The IMAP mission will also support near real-time observations of the solar wind and energetic solar particles, which can produce hazardous conditions in the space environment near Earth. From its location at Lagrange Point 1, about 1 million miles from Earth toward the Sun, IMAP will provide around a half hour’s warning of dangerous particles headed toward our planet. The mission’s data will help with the development of models that can predict the impacts of space weather ranging from power-line disruptions to loss of satellites.
      “The IMAP mission will provide very important information for deep space travel, where astronauts will be directly exposed to the dangers of the solar wind,” said David McComas, IMAP principal investigator at Princeton University.
      Cosmic dust: hints of the galaxy beyond
      In addition to measuring ENAs and solar wind particles, IMAP will also make direct measurements of interstellar dust — clumps of particles originating outside of the solar system that are smaller than a grain of sand. This space dust is largely composed of rocky or carbon-rich grains leftover from the aftermath of supernova explosions. 
      The specific elemental composition of this space dust is a postmark for where it comes from in the galaxy. Studying cosmic dust can provide insight into the compositions of stars from far outside our solar system. It will also help scientists significantly advance what we know about these basic cosmic building materials and provide information on what the material between stars is made of.
      David McComas leads the mission with an international team of 27 partner institutions. APL is managing the development phase and building the spacecraft, and it will operate the mission. IMAP is the fifth mission in NASA’s Solar Terrestrial Probes Program portfolio. The Explorers and Heliophysics Projects Division at NASA Goddard manages the STP Program for the agency’s Heliophysics Division of NASA’s Science Mission Directorate. NASA’s Launch Services Program, based at NASA’s Kennedy Space Center in Florida, manages the launch service for the mission.
      By Mara Johnson-Groh
      NASA’s Goddard Space Flight Center, Greenbelt, Md.
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    • By NASA
      NASA’s Nancy Grace Roman Space Telescope will help scientists better understand our Milky Way galaxy’s less sparkly components — gas and dust strewn between stars, known as the interstellar medium.
      One of Roman’s major observing programs, called the Galactic Plane Survey, will peer through our galaxy to its most distant edge, mapping roughly 20 billion stars—about four times more than have currently been mapped. Scientists will use data from these stars to study and map the dust their light travels through, contributing to the most complete picture yet of the Milky Way’s structure, star formation, and the origins of our solar system.
      Our Milky Way galaxy is home to more than 100 billion stars that are often separated by trillions of miles. The spaces in between, called the interstellar medium, aren’t empty — they’re sprinkled with gas and dust that are both the seeds of new stars and the leftover crumbs from stars long dead. Studying the interstellar medium with observatories like NASA’s upcoming Nancy Grace Roman Space Telescope will reveal new insight into the galactic dust recycling system.
      Credit: NASA/Laine Havens; Music credit: Building Heroes by Enrico Cacace [BMI], Universal Production Music “With Roman, we’ll be able to turn existing artist’s conceptions of the Milky Way into more data-driven models using new constraints on the 3D distribution of interstellar dust,” said Catherine Zucker, an astrophysicist at the Center for Astrophysics | Harvard & Smithsonian in Cambridge, Massachusetts.
      Solving Milky Way mystery
      Scientists know how our galaxy likely looks by combining observations of the Milky Way and other spiral galaxies. But dust clouds make it hard to work out the details on the opposite side of our galaxy. Imagine trying to map a neighborhood while looking through the windows of a house surrounded by a dense fog.
      Roman will see through the “fog” of dust using a specialized camera and filters that observe infrared light — light with longer wavelengths than our eyes can detect. Infrared light is more likely to pass through dust clouds without scattering.
      This artist’s concept visualizes different types of light moving through a cloud of particles. Since infrared light has a longer wavelength, it can pass more easily through the dust. That means astronomers observing in infrared light can peer deeper into dusty regions.Credit: NASA’s Goddard Space Flight Center Light with shorter wavelengths, including blue light produced by stars, more easily scatters. That means stars shining through dust appear dimmer and redder than they actually are.
      By comparing the observations with information on the source star’s characteristics, astronomers can disentangle the star’s distance from how much its colors have been reddened. Studying those effects reveals clues about the dust’s properties.
      “I can ask, ‘how much redder and dimmer is the starlight that Roman detects at different wavelengths?’ Then, I can take that information and relate it back to the properties of the dust grains themselves, and in particular their size,” said Brandon Hensley, a scientist who studies interstellar dust at NASA’s Jet Propulsion Laboratory in Southern California.
      Scientists will also learn about the dust’s composition and probe clouds to investigate the physical processes behind changing dust properties.
      Clues in dust-influenced starlight hint at the amount of dust between us and a star. Piecing together results from many stars allows astronomers to construct detailed 3D dust maps. That would enable scientists like Zucker to create a model of the Milky Way, which will show us how it looks from the outside. Then scientists can better compare the Milky Way with other galaxies that we only observe from the outside, slotting it into a cosmological perspective of galaxy evolution.
      “Roman will add a whole new dimension to our understanding of the galaxy because we’ll see billions and billions more stars,” Zucker said. “Once we observe the stars, we’ll have the dust data as well because its effects are encoded in every star Roman detects.”
      Galactic life cycles
      The interstellar medium does more than mill about the Milky Way — it fuels star and planet formation. Dense blobs of interstellar medium form molecular clouds, which can gravitationally collapse and kick off the first stages of star development. Young stars eject hot winds that can cause surrounding dust to clump into planetary building blocks.
      “Dust carries a lot of information about our origins and how everything came to be,” said Josh Peek, an associate astronomer and head of the data science mission office at the Space Telescope Science Institute in Baltimore, Maryland. “Right now, we’re basically standing on a really large dust grain — Earth was built out of lots and lots of really tiny grains that grew together into a giant ball.”
      Roman will identify young clusters of stars in new, distant star-forming regions as well as contribute data on “star factories” previously identified by missions like NASA’s retired Spitzer Space Telescope.
      “If you want to understand star formation in different environments, you have to understand the interstellar landscape that seeds it,” Zucker said. “Roman will allow us to link the 3D structure of the interstellar medium with the 3D distribution of young stars across the galaxy’s disk.”
      Roman’s new 3D dust maps will refine our understanding of the Milky Way’s spiral structure, the pinwheel-like pattern where stars, gas, and dust bunch up like galactic traffic jams. By combining velocity data with dust maps, scientists will compare observations with predictions from models to help identify the cause of spiral structure—currently unclear.
      The role that this spiral pattern plays in star formation remains similarly uncertain. Some theories suggest that galactic congestion triggers star formation, while others contend that these traffic jams gather material but do not stimulate star birth.
      Roman will help to solve mysteries like these by providing more data on dusty regions across the entire Milky Way. That will enable scientists to compare many galactic environments and study star birth in specific structures, like the galaxy’s winding spiral arms or its central stellar bar.
      NASA’s Nancy Grace Roman Space Telescope will conduct a Galactic Plane Survey to explore our home galaxy, the Milky Way. The survey will map around 20 billion stars, each encoding information about intervening dust and gas called the interstellar medium. Studying the interstellar medium could offer clues about our galaxy’s spiral arms, galactic recycling, and much more.
      Credit: NASA, STScI, Caltech/IPAC The astronomy community is currently in the final stages of planning for Roman’s Galactic Plane Survey.
      “With Roman’s massive survey of the galactic plane, we’ll be able to have this deep technical understanding of our galaxy,” Peek said.
      After processing, Roman’s data will be available to the public online via the Roman Research Nexus and the Barbara A. Mikulski Archive for Space Telescopes, which will each provide open access to the data for years to come.
      “People who aren’t born yet are going to be able to do really cool analyses of this data,” Peek said. “We have a really beautiful piece of our heritage to hand down to future generations and to celebrate.”
      Roman is slated to launch no later than May 2027, with the team working toward a potential early launch as soon as fall 2026.
      The Nancy Grace Roman Space Telescope is managed at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, with participation by NASA’s Jet Propulsion Laboratory and Caltech/IPAC in Southern California, the Space Telescope Science Institute in Baltimore, and a science team comprising scientists from various research institutions. The primary industrial partners are BAE Systems Inc. in Boulder, Colorado; L3Harris Technologies in Rochester, New York; and Teledyne Scientific & Imaging in Thousand Oaks, California.
      Download additional images and video from NASA’s Scientific Visualization Studio.
      For more information about the Roman Space Telescope, visit:
      https://www.nasa.gov/roman
      By Laine Havens
      NASA’s Goddard Space Flight Center, Greenbelt, Md.
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      Last Updated Sep 16, 2025 EditorAshley BalzerContactAshley Balzerashley.m.balzer@nasa.govLocationGoddard Space Flight Center Related Terms
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    • By NASA
      Advancing Single-Photon Sensing Image Sensors to Enable the Search for Life Beyond Earth
      A NASA-sponsored team is advancing single-photon sensing Complementary Metal-Oxide-Semiconductor (CMOS) detector technology that will enable future NASA astrophysics space missions to search for life on other planets. As part of their detector maturation program, the team is characterizing sensors before, during, and after high-energy radiation exposure; developing novel readout modes to mitigate radiation-induced damage; and simulating a near-infrared CMOS pixel prototype capable of detecting individual photons.
      Single-photon sensing and photon-number resolving CMOS image sensors: a 9.4 Mpixel sensor (left) and a 16.7 Mpixel sensor (right). Credit: CfD, RIT Are we alone in the universe? This age-old question has inspired scientific exploration for centuries. If life on other planets evolves similarly to life on Earth, it can imprint its presence in atmospheric spectral features known asbiosignatures. They include absorption and emission lines in the spectrum produced by oxygen, carbon dioxide, methane, and other molecules that could indicate conditions which can support life. A future NASA astrophysics mission, the Habitable Worlds Observatory (HWO), will seek to find biosignatures in the ultraviolet, optical, and near-infrared (NIR) spectra of exoplanet atmospheres to look for evidence that life may exist elsewhere in the universe.
      HWO will need highly sensitive detector technology to detect these faint biosignatures on distant exoplanets. The Single-Photon Sensing Complementary Metal-Oxide-Semiconductor (SPSCMOS) image sensor is a promising technology for this application. These silicon-based sensors can detect and resolve individual optical-wavelength photons using a low-capacitance, high-gain floating diffusion sense node. They operate effectively over a broad temperature range, including at room temperature. They have near-zero read noise, are tolerant to radiation, and generate very little unwanted signal—such as dark current. When cooled to 250 K, the dark current drops to just one electron every half-hour. If either the read noise or dark current is too high, the sensor will fail to detect the faint signals that biosignatures produce.
      A research team at the Rochester Institute of Technology (RIT) Center for Detectors (CfD) is accelerating the readiness of these SPSCMOS sensors for use in space missions through detector technology maturation programs funded by NASA’s Strategic Astrophysics Technology and Early Stage Innovations solicitations. These development programs include several key goals:
      Characterize critical detector performance metrics like dark current, quantum efficiency, and read noise before, during, and after exposure to high-energy radiation Develop new readout modes for these sensors to mitigate effects from short-term and long-term radiation damage Design a new NIR version of the sensor using Technology Computer-Aided Design (TCAD) software SPSCMOS sensors operate similarly to traditional CMOS image sensors but are optimized to detect individual photons—an essential capability for ultra-sensitive space-based observations, such as measuring the gases in the atmospheres of exoplanets. Incoming photons enter the sensor and generate free charges (electrons) in the sensor material. These charges collect in a pixel’s storage well and eventually transfer to a low-capacitance component called the floating diffusion (FD) sense node where each free charge causes a large and resolved voltage shift. This voltage shift is then digitized to read the signal.
      Experiments that measure sensor performance in a space relevant environment use a vacuum Dewar and a thermally-controlled mount to allow precise tuning of the sensors temperature. The Dewar enables testing at conditions that match the expected thermal environment of the HWO instrument, and can even cool the sensor and its on-chip circuits to temperatures colder than any prior testing reported for this detector family. These tests are critical for revealing performance limitations with respect to detector metrics like dark current, quantum efficiency, and read noise. As temperatures change, the electrical properties of on-chip circuits can also change, which affects the read out of charge in a pixel.
      The two figures show results for SPSCMOS devices. The figure on the left shows a photon counting histogram with peaks that correspond to photon number. The figure on the right shows the dark current for a SPSCMOS device before and after exposure to 50 krad of 60 MeV protons. Credit: CfD, RIT The radiation-rich environment for HWO will cause temporary and permanent effects in the sensor. These effects can corrupt the signal measured in a pixel, interrupt sensor clocking and digital logic, and can cause cumulative damage that gradually degrades sensor performance. To mitigate the loss of detector sensitivity throughout a mission lifetime, the RIT team is developing new readout modes that are not available in commercial CMOS sensors. These custom modes sample the signal over time (a “ramp” acquisition) to enable the detection and removal of cosmic ray artifacts. In one mode, when the system identifies an artifact, it segments the signal ramp and selectively averages the segments to reconstruct the original signal—preserving scientific data that would otherwise be lost. In addition, a real-time data acquisition system monitors the detector’s power consumption, which may change from the accumulation of damage throughout a mission. The acquisition system records these shifts and communicates with the detector electronics to adjust voltages and maintain nominal operation. These radiation damage mitigation strategies will be evaluated during a number of test programs at ground-based radiation facilities. The tests will help identify unique failure mechanisms that impact SPSCMOS technology when it is exposed to radiation equivalent to the dose expected for HWO.
      Custom acquisition electronics (left) that will control the sensors during radiation tests, and an image captured using this system (right). Credit: CfD, RIT While existing SPSCMOS sensors are limited to detecting visible light due to their silicon-based design, the RIT team is developing the world’s first NIR single-photon photodiode based on the architecture used in the optical sensors. The photodiode design starts as a simulation in TCAD software to model the optical and electrical properties of the low-capacitance CMOS architecture. The model simulates light-sensitive circuits using both silicon and Mercury Cadmium Telluride (HgCdTe or MCT) material to determine how well the pixel would measure photo-generated charge if a semiconductor foundry physically fabricated it. It has 2D and 3D device structures that convert light into electrical charge, and circuits to control charge transfer and signal readout with virtual probes that can measure current flow and electric potential. These simulations help to evaluate the key mechanisms like the conversion of light into electrons, storing and transferring the electrons, and the output voltage of the photodiode sampling circuit.
      In addition to laboratory testing, the project includes performance evaluations at a ground-based telescope. These tests allow the sensor to observe astronomical targets that cannot be fully replicated in lab. Star fields and diffuse nebulae challenge the detector’s full signal chain under real sky backgrounds with faint flux levels, field-dependent aberrations, and varying seeing conditions. These observations help identify performance limitations that may not be apparent in controlled laboratory measurements.
      In January 2025, a team of researchers led by PhD student Edwin Alexani used an SPSCMOS-based camera at the C.E.K. Mees Observatory in Ontario County, New York. They observed star cluster M36 to evaluate the sensor’s photometric precision, and the Bubble Nebula in a narrow-band H-alpha filter. The measured dark current and read noise were consistent with laboratory results.
      The team observed photometric reference stars to estimate the quantum efficiency (QE) or the ability for the detector to convert photons into signal. The calculated QE agreed with laboratory measurements, despite differences in calibration methods.
      The team also observed the satellite STARLINK-32727 as it passed through the telescope’s field of view and measured negligible persistent charge—residual signal that can remain in detector pixels after exposure to a bright source. Although the satellite briefly produced a bright streak across several pixels due to reflected sunlight, the average latent charge in affected pixels was only 0.03 e–/pix – well below both the sky-background and sensor’s read noise.
      Images captured at the C.E.K. Mees Observatory. Left: The color image shows M36 in the Johnson color filters B (blue), V (green), and R (red) bands (left). Right: Edwin Alexani and the SPSCMOS camera (right). Credit: : CfD, RIT As NASA advances and matures the HWO mission, SPSCMOS technology promises to be a game-changer for exoplanet and general astrophysics research. These sensors will enhance our ability to detect and analyze distant worlds, bringing us one step closer to answering one of humanity’s most profound questions: are we alone?
      For additional details, see the entry for this project on NASA TechPort.
      Project Lead(s): Dr. Donald F. Figer, Future Photon Initiative and Center for Detectors, Rochester Institute of Technology (RIT), supported by engineer Justin Gallagher and a team of students.
      Sponsoring Organization(s): NASA Astrophysics Division, Strategic Astrophysics Technology (SAT) Program and NASA Space Technology Mission Directorate (STMD), Early Stage Innovations (ESI) Program
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      Last Updated Sep 02, 2025 Related Terms
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      Preparations for Next Moonwalk Simulations Underway (and Underwater)
      Written by Michael Allen
      An international team of astronomers using NASA’s IXPE (Imaging X-ray Polarimetry Explorer), has challenged our understanding of what happens to matter in the direct vicinity of a black hole.
      With IXPE, astronomers can study incoming X-rays and measure the polarization, a property of light that describes the direction of its electric field.
      The polarization degree is a measurement of how aligned those vibrations are to each other. Scientists can use a black hole’s polarization degree to determine the location of the corona – a region of extremely hot, magnetized plasma that surrounds a black hole – and how it generates X-rays.
      This illustration of material swirling around a black hole highlights a particular feature, called the “corona,” that shines brightly in X-ray light. In this depiction, the corona can be seen as a purple haze floating above the underlying accretion disk, and extending slightly inside of its inner edge. The material within the inner accretion disk is incredibly hot and would glow with a blinding blue-white light, but here has been reduced in brightness to make the corona stand out with better contrast. Its purple color is purely illustrative, standing in for the X-ray glow that would not be obvious in visible light. The warp in the disk is a realistic representation of how the black hole’s immense gravity acts like an optical lens, distorting our view of the flat disk that encircles it. NASA/Caltech-IPAC/Robert Hurt In April, astronomers used IXPE to measure a 9.1% polarization degree for black hole IGR J17091-3624, much higher than they expected based on theoretical models.
      “The black hole IGR J17091-3624 is an extraordinary source which dims and brightens with the likeness of a heartbeat, and NASA’s IXPE allowed us to measure this unique source in a brand-new way.” said Melissa Ewing, the lead of the study based at Newcastle University in Newcastle upon Tyne, England.
      In X-ray binary systems, an extremely dense object, like a black hole, pulls matter from a nearby source, most often a neighboring star. This matter can begin to swirl around, flattening into a rotating structure known as an accretion disc.
      The corona, which lies in the inner region of this accretion disc, can reach extreme temperatures up to 1.8 billion degrees Fahrenheit and radiate very luminous X-rays. These ultra-hot coronas are responsible for some of the brightest X-ray sources in the sky.
      Despite how bright the corona is in IGRJ17091-364, at some 28,000 light-years from Earth, it remains far too small and distant for astronomers to capture an image of it.
      “Typically, a high polarization degree corresponds with a very edge-on view of the corona. The corona would have to be perfectly shaped and viewed at just the right angle to achieve such a measurement,” said Giorgio Matt, professor at the University of Roma Tre in Italy and a co-author on this paper. “The dimming pattern has yet to be explained by scientists and could hold the keys to understanding this category of black holes.”
      The stellar companion of this black hole isn’t bright enough for astronomers to directly estimate the system’s viewing angle, but the unusual changes in brightness observed by IXPE suggest that the edge of the accretion disk was directly facing Earth.
      The researchers explored different avenues to explain the high polarization degree.
      In one model, astronomers included a “wind” of matter lifted from the accretion disc and launched away from the system, a rarely seen phenomenon. If X-rays from the corona were to meet this matter on their way to IXPE, Compton scattering would occur, leading to these measurements.
      Fast Facts
      Polarization measurements from IXPE carry information about the orientation and alignment of emitted X-ray light waves. The high the degree of polarization, the more the X-ray waves are traveling in sync. Most polarization in the corona come from a process known as Compton scattering, where light from the accretion disc bounces off the hot plasma of the corona, gaining energy and aligning to vibrate in the same direction. “These winds are one of the most critical missing pieces to understand the growth of all types of black holes,” said Maxime Parra, who led the observation and works on this topic at Ehime University in Matsuyama, Japan. “Astronomers could expect future observations to yield even more surprising polarization degree measurements.”
      Another model assumed the plasma in the corona could exhibit a very fast outflow. If the plasma were to be streaming outwards at speeds as high as 20% the speed of light, or roughly 124 million miles per hour, relativistic effects could boost the observed polarization.
      In both cases, the simulations could recreate the observed polarization without a very specific edge-on view. Researchers will continue to model and test their predictions to better understand the high polarization degree for future research efforts.
      More about IXPE
      IXPE, which continues to provide unprecedented data enabling groundbreaking discoveries about celestial objects across the universe, is a joint NASA and Italian Space Agency mission with partners and science collaborators in 12 countries. IXPE is led by NASA’s Marshall Space Flight Center in Huntsville, Alabama. BAE Systems, Inc., headquartered in Falls Church, Virginia, manages spacecraft operations together with the University of Colorado’s Laboratory for Atmospheric and Space Physics in Boulder.
      Learn more about IXPE’s ongoing mission here:
      https://www.nasa.gov/ixpe
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      Last Updated Aug 12, 2025 EditorBeth RidgewayContactCorinne Edmistoncorinne.m.edmiston@nasa.govLocationMarshall Space Flight Center Related Terms
      IXPE (Imaging X-ray Polarimetry Explorer) Marshall Astrophysics Marshall Science Research & Projects Marshall Space Flight Center Explore More
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