Members Can Post Anonymously On This Site
Tyler Parsotan Takes a Long Look at the Transient Universe with NASA’s Swift
-
Similar Topics
-
By NASA
4 min read
NASA’s Swift Studies Gas-Churning Monster Black Holes
A pair of monster black holes swirl in a cloud of gas in this artist’s concept of AT 2021hdr, a recurring outburst studied by NASA’s Neil Gehrels Swift Observatory and the Zwicky Transient Facility at Palomar Observatory in California. NASA/Aurore Simonnet (Sonoma State University) Scientists using observations from NASA’s Neil Gehrels Swift Observatory have discovered, for the first time, the signal from a pair of monster black holes disrupting a cloud of gas in the center of a galaxy.
“It’s a very weird event, called AT 2021hdr, that keeps recurring every few months,” said Lorena Hernández-García, an astrophysicist at the Millennium Institute of Astrophysics, the Millennium Nucleus on Transversal Research and Technology to Explore Supermassive Black Holes, and University of Valparaíso in Chile. “We think that a gas cloud engulfed the black holes. As they orbit each other, the black holes interact with the cloud, perturbing and consuming its gas. This produces an oscillating pattern in the light from the system.”
A paper about AT 2021hdr, led by Hernández-García, was published Nov. 13 in the journal Astronomy and Astrophysics.
The dual black holes are in the center of a galaxy called 2MASX J21240027+3409114, located 1 billion light-years away in the northern constellation Cygnus. The pair are about 16 billion miles (26 billion kilometers) apart, close enough that light only takes a day to travel between them. Together they contain 40 million times the Sun’s mass.
Scientists estimate the black holes complete an orbit every 130 days and will collide and merge in approximately 70,000 years.
AT 2021hdr was first spotted in March 2021 by the Caltech-led ZTF (Zwicky Transient Facility) at the Palomar Observatory in California. It was flagged as a potentially interesting source by ALeRCE (Automatic Learning for the Rapid Classification of Events). This multidisciplinary team combines artificial intelligence tools with human expertise to report events in the night sky to the astronomical community using the mountains of data collected by survey programs like ZTF.
“Although this flare was originally thought to be a supernova, outbursts in 2022 made us think of other explanations,” said co-author Alejandra Muñoz-Arancibia, an ALeRCE team member and astrophysicist at the Millennium Institute of Astrophysics and the Center for Mathematical Modeling at the University of Chile. “Each subsequent event has helped us refine our model of what’s going on in the system.”
Since the first flare, ZTF has detected outbursts from AT 2021hdr every 60 to 90 days.
Hernández-García and her team have been observing the source with Swift since November 2022. Swift helped them determine that the binary produces oscillations in ultraviolet and X-ray light on the same time scales as ZTF sees them in the visible range.
The researchers conducted a Goldilocks-type elimination of different models to explain what they saw in the data.
Initially, they thought the signal could be the byproduct of normal activity in the galactic center. Then they considered whether a tidal disruption event — the destruction of a star that wandered too close to one of the black holes — could be the cause.
Finally, they settled on another possibility, the tidal disruption of a gas cloud, one that was bigger than the binary itself. When the cloud encountered the black holes, gravity ripped it apart, forming filaments around the pair, and friction started to heat it. The gas got particularly dense and hot close to the black holes. As the binary orbits, the complex interplay of forces ejects some of the gas from the system on each rotation. These interactions produce the fluctuating light Swift and ZTF observe.
To view this video please enable JavaScript, and consider upgrading to a web browser that
supports HTML5 video
Watch as a gas cloud encounters two supermassive black holes in this simulation. The complex interplay of gravitational and frictional forces causes the cloud to condense and heat. Some of the gas is ejected from the system with each orbit of the black holes. F. Goicovic et al. 2016 Hernández-García and her team plan to continue observations of AT 2021hdr to better understand the system and improve their models. They’re also interested in studying its home galaxy, which is currently merging with another one nearby — an event first reported in their paper.
“As Swift approaches its 20th anniversary, it’s incredible to see all the new science it’s still helping the community accomplish,” said S. Bradley Cenko, Swift’s principal investigator at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “There’s still so much it has left to teach us about our ever-changing cosmos.”
NASA’s missions are part of a growing, worldwide network watching for changes in the sky to solve mysteries of how the universe works.
Goddard manages the Swift mission in collaboration with Penn State, the Los Alamos National Laboratory in New Mexico, and Northrop Grumman Space Systems in Dulles, Virginia. Other partners include the University of Leicester and Mullard Space Science Laboratory in the United Kingdom, Brera Observatory in Italy, and the Italian Space Agency.
Download high-resolution images and videos.
By Jeanette Kazmierczak
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Media Contact:
Claire Andreoli
301-286-1940
claire.andreoli@nasa.gov
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Facebook logo @NASAUniverse @NASAUniverse Instagram logo @NASAUniverse Share
Details
Last Updated Nov 13, 2024 Editor Jeanette Kazmierczak Related Terms
Astrophysics Black Holes Galaxies, Stars, & Black Holes Galaxies, Stars, & Black Holes Research Goddard Space Flight Center Neil Gehrels Swift Observatory Science & Research Supermassive Black Holes The Universe View the full article
-
By NASA
NASA NASA pilot Joe Walker sits in the pilot’s platform of the Lunar Landing Research Vehicle (LLRV) number 1 on Oct. 30, 1964. The LLRV and its successor the Lunar Landing Training Vehicle (LLTV) provided the training tool to simulate the final 200 feet of the descent to the Moon’s surface.
The LLRVs, humorously referred to as flying bedsteads, were used by NASA’s Flight Research Center, now NASA’s Armstrong Flight Research Center in California, to study and analyze piloting techniques needed to fly and land the Apollo lunar module in the moon’s airless environment.
Learn more about the LLRV’s first flight.
Image credit: NASA
View the full article
-
By European Space Agency
Image: The construction phase of ESA’s Ariel mission has started at Airbus Defence and Space in Toulouse (France) with the assembly of the spacecraft’s structural model. This marks a significant step forward for this mission designed to meticulously inspect the atmospheres of a thousand exoplanets and uncover their nature.
In the image we see Ariel’s structural model coming together at the Airbus facilities. This model replicates the mechanical framework of the spacecraft and the mass of its various units for a first round of tough testing.
The Ariel’s structural model consists of two main components: a flight-like replica of the service module (bottom right) and a simplified mechanical mock-up of the payload module (top right). This assembly mimics the structure of the flight spacecraft, where the science instruments make up the payload while the service module houses the essential components for the functioning of the spacecraft, such as the propulsion, and the power and communication systems.
The goal for the end of the year is to complete the mechanical test campaign of the spacecraft’s structural model. This will ensure that Ariel’s design is up-to-spec and can withstand the mechanical strains expected during launch.
The testing phase will include vibration and acoustic test campaigns. During vibration tests the model will be progressively shaken at different strengths on a vibrating table, or 'the shaker'. During acoustic tests, it will be placed in a reverberating chamber and ‘bombarded’ with very intense noise, like it will encounter during launch.
This model will also be used to assess how the loads are distributed and to perform a first ‘separation and shock’ test using the same mounting system as will be used to mount the spacecraft on the Ariane 6.
When ready, Ariel will be launched by an Ariane 6.2 rocket and journey to the second Lagrangian Point from where it will carry out its uniquely detailed studies of remote worlds.
Image description: A collage of three photographs that show the assembly of the model of a spacecraft in a large white hall. The first image on the left shows the entire model, with a person next to it who is nearly equal in height. The second image on the upper right zooms in on the top part of the mock science instrument: a circular fan-like structure with a big rectangular silver box on top. The third image on the lower right focuses on the bottom of the model, which looks like a large round silver box.
View the full article
-
By NASA
4 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
The Skydweller Aero solar-powered, autonomous aircraft flies above the Thad Cochran Test Stand (B-1/B-2) at NASA’s Stennis Space Center during a September 2024 test operation. Skydweller Aero has an ongoing airspace agreement with NASA Stennis to conduct test flights of its aircraft in the area.Skydweller Aero NASA’s Stennis Space Center near Bay St. Louis, Mississippi, has entered into an agreement with Skydweller Aero Inc. for the company to operate its solar-powered autonomous aircraft in the site’s restricted airspace, a key step towards achieving a strategic center goal.
The Reimbursable Space Act agreement marks the first between NASA Stennis and a commercial company to utilize the south Mississippi center’s unique capabilities to support testing and operation of uncrewed systems.
“There are few locations like NASA Stennis that offer a secure location, restricted airspace and the infrastructure to support testing and operation of various uncrewed systems,” said NASA Stennis Director John Bailey. “Range operations is a critical area of focus as we adapt to the changing aerospace and technology landscape to grow into the future.”
NASA Stennis and Skydweller Aero finalized the agreement in late August, paving the way for the company to begin area test flights of its autonomous, uncrewed solar-powered aircraft, which features a wingspan greater than a 747 jetliner and is designed for long-duration flights. The company announced Oct. 1 it had completed an initial test flight campaign of the aircraft, including two test excursions totaling 16 and 22.5 hours.
NASA Stennis and Skydweller Aero began talks in the summer of 2023 when the company expressed interest in utilizing NASA Stennis airspace for its all-carbon fiber aircraft. The NASA Stennis area fits the company’s needs well since it provides ready access from Stennis International Airport to the Gulf of Mexico area. NASA Stennis airspace also provides a level of privacy for aircraft testing and operation.
“Access to the restricted airspace above NASA Stennis has been tremendously helpful to our uncrewed, autonomous flight operations,” said Barry Matsumori, president and chief operating officer of Skydweller Aero. “The opportunity to use the controlled environment above Stennis helps accelerate our efforts, allowing us to transition the aircraft in and out of civil airspace, while demonstrating its reliability and unblemished safety record to the FAA.”
Companies must be conducting public aircraft operations to use any restricted airspace. In this instance, Skydweller Aero is flying its aircraft in association with the U.S. Department of Defense, allowing for the Reimbursable Space Act agreement with NASA Stennis.
The agreement provides the company Federal Aviation Administration (FAA) authorization for future test flights in designated areas of the NASA Stennis buffer zone. It also represents a key step in the center’s effort to grow its range operations presence.
“This really opens the door for others to come here,” said Jason Peterson, NASA Stennis range officer. “There are requirements that must be met, but for those who meet them, NASA Stennis is an ideal location for test and flight operations.”
The FAA established restricted airspace at NASA Stennis in 1966 and approved its expansion in 2016. The expansion was necessary to conduct propulsion testing safely, accommodate U.S. Department of Defense missions, and support unmanned aerial systems activities.
Restricted airspace at NASA Stennis allows qualifying organizations to conduct various uncrewed flight activities. NASA Stennis personnel provide scheduling and range operation support, including reviews and evaluations to ensure safe flight operations. Processes are in place to ensure communication between aircraft operators, FAA air traffic controllers, and range safety personnel.
Peterson said he hopes the agreement with Skydweller Aero will clear the way for future collaborations as NASA Stennis continues to expand its customer-based operations. For instance, although Skydweller Aero is not located onsite, NASA Stennis is able to support ground operations for a variety of unmanned aircraft system takeoffs and landings.
Beyond that, the center also hopes to expand its operational capabilities to include marine and ground activities. In addition to a large geographic footprint, the center features a secure 7.5-mile waterway canal system for testing unmanned underwater or surface vehicles.
For information about range operations at NASA’s Stennis Space Center, visit:
Range and Airspace Operations – NASA
Share
Details
Last Updated Oct 23, 2024 EditorNASA Stennis CommunicationsContactC. Lacy Thompsoncalvin.l.thompson@nasa.gov / (228) 688-3333LocationStennis Space Center Related Terms
Stennis Space Center Keep Exploring Discover More Topics From NASA Stennis
Range and Airspace Operations
Propulsion Test Engineering
NASA Stennis Front Door
Doing Business with NASA Stennis
View the full article
-
By NASA
The study of X-ray emission from astronomical objects reveals secrets about the Universe at the largest and smallest spatial scales. Celestial X-rays are produced by black holes consuming nearby stars, emitted by the million-degree gas that traces the structure between galaxies, and can be used to predict whether stars may be able to host planets hospitable to life. X-ray observations have shown that most of the visible matter in the universe exists as hot gas between galaxies and have conclusively demonstrated that the presence of “dark matter” is needed to explain galaxy cluster dynamics, that dark matter dominates the mass of galaxy clusters, and that it governs the expansion of the cosmos.
X-ray observations also enable us to probe mysteries of the Universe on the smallest scales. X-ray observations of compact objects such as white dwarfs, neutron stars, and black holes allow us to use the Universe as a physics laboratory to study conditions that are orders of magnitude more extreme in terms of density, pressure, temperature, and magnetic field strength than anything that can be produced on Earth. In this astrophysical laboratory, researchers expect to reveal new physics at the subatomic scale by conducting investigations such as probing the neutron star equation of state and testing quantum electrodynamics with observations of neutron star atmospheres. At NASA’s Marshall Space Flight Center, a team of scientists and engineers is building, testing, and flying innovative optics that bring the Universe’s X-ray mysteries into sharper focus.
A composite X-ray/Optical/Infrared image of the Crab Pulsar. The X-ray image from the Chandra X-ray Observatory (blue and white), reveals exquisite details in the central ring structures and gas flowing out of the polar jets. Optical light from the Hubble Space Telescope (purple) shows foreground and background stars as pinpoints of light. Infrared light from the Spitzer Space Telescope (pink) traces cooler gas in the nebula. Finally, magnetic field direction derived from X-ray polarization observed by the Imaging X-ray Polarimetry Explorer is shown as orange lines. Magnetic field lines: NASA/Bucciantini et al; X-ray: NASA/CXC/SAO; Optical: NASA/STScI; Infrared: NASA-JPL-Caltech Unlike optical telescopes that create images by reflecting or refracting light at near-90-degree angles (normal incidence), focusing X-ray optics must be designed to reflect light at very small angles (grazing incidence). At normal incidence, X-rays are either absorbed by the surface of a mirror or penetrate it entirely. However, at grazing angles of incidence, X-rays reflect very efficiently due to an effect called total external reflection. In grazing incidence, X-rays reflect off the surface of a mirror like rocks skipping on the surface of a pond.
A classic design for astronomical grazing incidence optics is the Wolter-I prescription, which consists of two reflecting surfaces, a parabola and hyperbola (see figure below). This optical prescription is revolved around the optical axis to produce a full-shell mirror (i.e., the mirror spans the full circumference) that resembles a gently tapered cone. To increase the light collecting area, multiple mirror shells with incrementally larger diameters and a common focus are fabricated and nested concentrically to comprise a mirror module assembly (MMA).
Focusing optics are critical to studying the X-ray universe because, in contrast to other optical systems like collimators or coded masks, they produce high signal-to-noise images with low background noise. Two key metrics that characterize the performance of X-ray optics are angular resolution, which is the ability of an optical system to discriminate between closely spaced objects, and effective area, which is the light collecting area of the telescope, typically quoted in units of cm2. Angular resolution is typically measured as the half-power diameter (HPD) of a focused spot in units of arcseconds. The HPD encircles half of the incident photons in a focused spot and measures the sharpness of the final image; a smaller number is better.
Schematic of a full-shell Wolter-I X-ray optic mirror module assembly with five concentrically nested mirror shells. Parallel rays of light enter from the left, reflect twice off the reflective inside surface of the shell (first off the parabolic segment and then off the hyperbolic segment), and converge at the focal plane. NASA MSFC NASA Marshall Space Flight Center (MSFC) has been building and flying lightweight, full-shell, focusing X-ray optics for over three decades, always meeting or exceeding angular resolution and effective area requirements. MSFC utilizes an electroformed nickel replication (ENR) technique to make these thin full-shell X-ray optics from nickel alloy.
X-ray optics development at MSFC began in the early 1990s with the fabrication of optics to support NASA’s Advanced X-ray Astrophysics Facility (AXAF-S) and then continued via the Constellation-X technology development programs. In 2001, MSFC launched a balloon payload that included two modules each with three mirrors, which produced the first focused hard X-ray (>10 keV) images of an astrophysical source by imaging Cygnus X-1, GRS 1915, and the Crab Nebula. This initial effort resulted in several follow-up missions over the next 12 years, and became known as the High Energy Replicated Optics (HERO) balloon program.
In 2012, the first of four sounding rocket flights of the Focusing Optics X-ray Solar Imager (FOXSI) flew with MSFC optics onboard, producing the first focused images of the Sun at energies greater than 5 keV. In 2019 the Astronomical Roentgen Telescope X-ray Concentrator (ART-XC) instrument on the Spectr-Roentgen-Gamma Mission launched with seven MSFC-fabricated X-ray MMAs, each containing 28 mirror shells. ART-XC is currently mapping the sky in the 4-30 keV hard X-ray energy range, studying exotic objects like neutron stars in our own galaxy as well as active galactic nuclei, which are spread across the visible universe. In 2021, the Imaging X-ray Polarimetry Explorer (IXPE), flew and is now performing extraordinary science with an MSFC-led team using three, 24-shell MMAs that were fabricated and calibrated in-house.
Most recently, in 2024, the fourth FOXSI sounding rocket campaign launched with a high-resolution MSFC MMA. The optics achieved 9.5 arcsecond HPD angular resolution during pre-flight test with an expected 7 arcsecond HPD in gravity-free flight, making this the highest angular resolution flight observation made with a nickel-replicated X-ray optic. Currently MSFC is fabricating an MMA for the Rocket Experiment Demonstration of a Soft X-ray (REDSoX) polarimeter, a sounding rocket mission that will fly a novel soft X-ray polarimeter instrument to observe active galactic nuclei. The REDSoX MMA optic will be 444 mm in diameter, which will make it the largest MMA ever produced by MSFC and the second largest replicated nickel X-ray optic in the world.
Scientists Wayne Baumgartner (left, crouched) and Nick Thomas (left, standing) calibrate an IXPE MMA in the MSFC 100 m Beamline. Scientist Stephen Bongiorno (right) applies epoxy to an IXPE shell during MMA assembly. NASA MSFC The ultimate performance of an X-ray optic is determined by errors in the shape, position, and roughness of the optical surface. To push the performance of X-ray optics toward even higher angular resolution and achieve more ambitious science goals, MSFC is currently engaged in a fundamental research and development effort to improve all aspects of full-shell optics fabrication.
Given that these optics are made with the Electroformed Nickel Replication technique, the fabrication process begins with creation of a replication master, called the mandrel, which is a negative of the desired optical surface. First, the mandrel is figured and polished to specification, then a thin layer of nickel alloy is electroformed onto the mandrel surface. Next, the nickel alloy layer is removed to produce a replicated optical shell, and finally the thin shell is attached to a stiff holding structure for use.
Each step in this process imparts some degree of error into the final replicated shell. Research and development efforts at MSFC are currently concentrating on reducing distortion induced during the electroforming metal deposition and release steps. Electroforming-induced distortion is caused by material stress built into the electroformed material as it deposits onto the mandrel. Decreasing release-induced distortion is a matter of reducing adhesion strength between the shell and mandrel, increasing strength of the shell material to prevent yielding, and reducing point defects in the release layer.
Additionally, verifying the performance of these advanced optics requires world-class test facilities. The basic premise of testing an optic designed for X-ray astrophysics is to place a small, bright X-ray source far away from the optic. If the angular size of the source, as viewed from the optic, is smaller than the angular resolution of the optic, the source is effectively simulating X-ray starlight. Due to the absorption of X-rays by air, the entire test facility light path must be placed inside a vacuum chamber.
At MSFC, a group of scientists and engineers operate the Marshall 100-meter X-ray beamline, a world-class end-to-end test facility for flight and laboratory X-ray optics, instruments, and telescopes. As per the name, it consists of a 100-meter-long vacuum tube with an 8-meter-long, 3-meter-diameter instrument chamber and a variety of X-ray sources ranging from 0.25 – 114 keV. Across the street sits the X-Ray and Cryogenic Facility (XRCF), a 527-meter-long beamline with an 18-meter-long, 6-meter-diameter instrument chamber. These facilities are available for the scientific community to use and highlight the comprehensive optics development and test capability that Marshall is known for.
Within the X-ray astrophysics community there exist a variety of angular resolution and effective area needs for focusing optics. Given its storied history in X-ray optics, MSFC is uniquely poised to fulfill requirements for large or small, medium- or high-angular-resolution X-ray optics. To help guide technology development, the astrophysics community convenes once per decade to produce a decadal survey. The need for high-angular-resolution and high-throughput X-ray optics is strongly endorsed by the National Academies of Sciences, Engineering, and Medicine report, Pathways to Discovery in Astronomy and Astrophysics for the 2020s.In pursuit of this goal, MSFC is continuing to advance the state of the art in full-shell optics. This work will enable the extraordinary mysteries of the X-ray universe to be revealed.
Project Leads
Dr. Jessica Gaskin and Dr. Stephen Bongiorno, NASA Marshall Space Flight Center (MSFC)
Sponsoring Organizations
The NASA Astrophysics Division supports this work primarily through the Internal Scientist Funding Model Direct Work Package and competed solicitations. This work is also supported by the Heliophysics Division through competed solicitations, as well as by directed work from other government entities.
Share
Details
Last Updated Oct 15, 2024 Related Terms
Astrophysics Astrophysics Division Marshall Astrophysics Marshall Space Flight Center Science-enabling Technology Technology Highlights Explore More
2 min read Hubble Spots a Grand Spiral of Starbursts
Article
4 days ago
6 min read NASA’s Hubble, New Horizons Team Up for a Simultaneous Look at Uranus
Article
6 days ago
4 min read NASA’s Hubble Watches Jupiter’s Great Red Spot Behave Like a Stress Ball
Article
6 days ago
View the full article
-
-
Check out these Videos
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.