Marshall Space Flight Center's Astrophysics Branch uses space and ground-based observatories to peer back to the earliest epochs of the universe, unravel its mysteries, and study the most violent explosions in our galaxy and beyond. Our goal is to help discover how the universe works, explore how it began and evolved, and search for life on planets around other stars.
Marshall scientist presents ground-breaking gamma-ray research at conference in Japan.
Dr. Daniel Kocevski gave an invited talk on the high-energy detection of GRB 190114C at a conference held in Yokohama, Japan. The talk focused on the Fermi and Swift contributions to a paper reporting the first very high-energy detection of a gamma-ray burst (GRB) by ground-based air Cherenkov telescopes. The detection gave high-energy astrophysicists a better understanding of accelerated mechanisms that generate the gamma-rays from these events. The paper has been accepted for publication in the journal Nature.
On January 14, 2019, just before 4:00 p.m. EST, both the Fermi Gamma-ray Space Telescope and the Neil Gehrels Swift Observatory detected a spike of gamma rays from the constellation Fornax. These distant explosions have produced the highest-energy light yet seen from these events, called gamma-ray bursts, or GRBs. The missions alerted the astronomical community to the location of the burst, dubbed GRB 190114C.
One facility receiving the alerts was the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) observatory located on La Palma in the Canary Islands, Spain. Both of its 17-meter telescopes automatically turned to the site of the facing burst. They began observing the GRB just 50 seconds after it was discovered and captured the most energetic gamma rays yet seen from these events. With GRB 190114C, MAGIC became the first facility to report unambiguous very high-energy (VHE) emission, with energies up to a trillion electron volts (1 TeV). That's 10 times the peak energy Fermi has seen to date.
Scientists suspect that most of the gamma rays from GRB afterglows originate in magnetic fields at the jet's leading edge. High-energy electrons spiraling in the fields directly emit gamma rays through a mechanism called synchotron emission. But other scientists, including the MAGIC team, interpret the VHE emission as a distinct afterglow component, which means some additional process must be at work, perhaps inverse Compton scattering. High-energy electrons in the jet crash into lower-energy gamma rays and boost them to much higher energies.
In the paper detailing the Fermi and Swift observations, the researchers conclude that an additional physical mechanism may be needed to produce the VHE emission. Within the lower energies observed by these missions, however, the flood of synchotron gamma rays makes uncovering a second process much more difficult.
Several papers have been published about GRB 190114C. Dr. Kocevski's invited talk presented information from the paper titled "Fermi and Swift Observations for GRB 190114c: Tracing the Evolution of High-Energy Emission from Prompt to Afterglow," for which he was one of the authors.
This paper on the Fermi and Swift contributions can be found at https://arxiv.org/abs/1909.10605.
Additional data and information about MAGIC and GRB 190114C can be found at: https://www.nature.com/articles/s41586-019-1750-x.
Read the Goddard press release here: https://www.nasa.gov/feature/goddard/2019/nasa-s-fermi-swift-missions-enable-a-new-era-in-gamma-ray-science/.
Time Domain Astronomy with the Fermi Gamma-Ray Burst Monitor in the Multimessenger Era presented at Yale University.
On Thursday, November 7, 2019, Dr. Colleen Wilson-Hodge presented an invited Yale Astronomy and Astrophysics Colloquium about the Fermi Gamma-ray Burst Monitor and its exciting science for transients ranging from gravitational wave counterparts to pulsars and magnetars to solar flares and terrestrial gamma-ray flashes. During an impromptu lunchtime talk, when she was asked to speak extemporaneously without slides, she described her experiences with current and future missions for NASA, including the path that led to her involvement in the Spectroscopic Time-Resolving Observatory for Broadband Energy X-rays (STROBE-X).
To find out more about STROBE-X, go to this site: https://gammaray.nsstc.nasa.gov/Strobe-X/index.html.
To view a link to the seminar, visit: https://astronomy.yale.edu/event/yale-astronomy-astrophysics-colloquium-colleen-wilson-hodge.
Lynx team presented to the ASTRO2020 Panel on the Electromagnetic Observations from Space 2
On November 6, 2018, the Lynx Team presented to the Astro2020 EOS2 panel on the science, technical, and cost of the Lynx mission. Lynx is one of four flagship mission concepts that would launch in the 2030s, after the James Webb Space Telescope and the Wide Field InfraRed Survey Telescope. if prioritized by the Astro2020 Decadal. The Decadal Survey on Astronomy and Astrophysics (Astro2020) is a partnership between the National Academies and the Astronomical community to identify key priorities in astronomy and astrophysics and develop a comprehensive strategy for agency investments in the upcoming decade. Participants from MSFC included Karen Gelmis (ST14), Jessica Gaskin (ST14), and Douglas Swartz (ST12/USRA).
Lynx will provide unprecedented X-ray vision into the otherwise "Invisible" Universe with unique power to directly observe the dawn of supermassive black holes, reveal the drivers of galaxy formation, trace stellar activity including effects on planet habitability, and transform our knowledge of endpoints of stellar evolution.
The clumpy and lumpy death of a star.
A Chandra press release was issued on October 17, 2019 describing new data from Chandra and other telescopes providing a new image of the Tycho supernova remnant from Chandra. The pattern shows bright clumps and fainter holes in the X-ray data. Scientists are trying to determine if this "clumpiness" was caused by the supernova explosion itself or something in tis aftermath. By comparing Chandra data to computer simulations, researchers found evidence that the explosion was likely the source of this lumpy distribution. The original supernova was first seen by skywatchers in 1572, including the Danish astronomer Tycho Brahe for whom the object was eventually named.
For more information go to https://chandra.cfa.harvard.edu/photo/2019/tycho/.
Chandra spots a mega-cluster of galaxies in the making.
A Chandra press release was issued on October 24, 2019, describing a mega-merger of four galaxy clusters in Abell 1758 which was observed by Chandra and other telescopes. Abell 1758 contains two pairs of galaxy clusters, each with hundreds of galaxies embedded in large amounts of hot gas and unseen dark matter. Eventually these two pairs of clusters will collide to form one of the most massive objects in the Universe. The X-rays from Chandra helped astronomers estimate how fast one pair of clusters were moving toward each other.
For more information, go to https://chandra.cfa.harvard.edu/photo/2019/a1758/.
Fermi Gamma-ray Burst Monitor (GBM) continues to follow up unique gravitational wave detections.
September has been an exciting time for the gamma-ray follow up by the Fermi Gamma-ray Burst Monitor of gravitational wave detections. The past four weeks saw the detection of two binary neutron star merger candidates and three neutron star black hole merger candidates by the LIGO Scientific collaboration and the Virgo Collaboration. The merger of two neutron stars has long been thought to be the origin of short GRBs, a theory that was confirmed by the detection of GRB 170817 in both gamma-rays and gravitational waves. It is currently an open question as to whether neutron star black hole mergers could also produce short GRBs, and the past few months have seen the first of these kind of detections by LIGO and Virgo. the GBM did not detect coincident emission from any of the recent binary neutron star or neutron star black hole mergers, but additional observations of such events gives astronomers valuable insight into the ubiquity of electromagnetic emission from such mergers and may be used in the future to constrain theories that aim to explain how these systems work.
Fermi and Swift Observations of GRB 190114C: Tracing the evolution of high-energy emission from prompt to afterglow.
The Fermi Gamma-ray Burst Monitor (GBM) team in Huntsville, working with members of the Fermi Large Area Telescope (LAT) collaboration and the Neil Gehrels Swift Observatory, released a paper on the high-energy observations of gamma-ray burst (GRB) 190114C. GRB 190114C was a unique event in that it was the first GRB ever detected by a ground-based Cherenkov telescope at energies in excess of 1 TeV. Long GRBs result from the explosion of massive stars in distant galaxies and are among the most energetic supernovae ever detected. the Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescope, located in the Canary Islands, was able to observe the GRB within a minute of its detection by GBM and Swift. The MAGIC observations revealed gamma-ray emission over a million times higher in energy than the emission typically observed by GBM from these events. The combined Fermi and Swift observations placed these VHE observations in context, but providing comprehensive observations at lower energies and revealed how that emission evolved with time.
Using these observations, the Fermi and Swift teams were able to estimate the energy and speed of the relativistic blast wave that was created when the progenitor star went supernova. Being able to measure these properties allowed the Fermi and Swift teams to show that a theory used to explain the emission observed by the GBM and LAT instruments could not also explain the VHE emission observed by MAGIC and that an additional emission mechanism would be needed. The combined observations ultimately allows astronomers to obtain a better understanding of the physics behind the most energetic explosions in the Universe.
You can find the paper online at https://arxiv.org/abs/1909.10605.
Evaluation of Automated Fermi GBM Localizations of Gamma-ray Bursts
The Fermi Gamma-ray Burst Monitor (GBM) detects onboard roughly 240 gamma-ray bursts (GRBs) a year, and the localization of these events and other transients observed by GBM are of prime importance in the era of multi-messenger and time-domain astronomy. To this end, an accurate estimate of the GBM localization uncertainty is a requirement to prevent reporting over-confident localizations that may result in false counterpart associations or lead to ruling out real associations. Therefore, it is important for GBM localizations to be as precise as possible and to account for systematic uncertainty to ensure the overall reported accuracy is reliable.
The GBM team implemented improvements to its automated localization algorithm of GRBs, called RoboBA, and compared the operation of the original and updated version of RoboBA to an alternative, independently-developed localization algorithm, BALROG. Through a systematic study utilizing over 500 GRBs with known locations from instruments like Swift and the Fermi LAT, the GBM team directly compare the effectiveness of, and accurately estimate the systematic uncertainty for, both algorithms.
The GBM team showed that simple adjustments to RoboBA, in operation since early 2016, yields significant improvement in the systematic uncertainty, removing the long tail previously identified in the systematic, and improved the overall accuracy. The systematic uncertainty for the updated RoboBA localizations is 1.8 deg. for 52% of GRBs and 4.1 deg. for the remaining 48%. Both from public reporting by BALROG and the GBM team's systematic study, the systematic uncertainty of 1-2 deg. quoted by the BALROG team for bright GRBs is an underestimate of the true magnitude of the systematic, which is found to be 2.7 deg. for 74% of GRBs and 33 deg. for the remaining 26%. The GBM team showed that, once the systematic uncertainty is considered, the RoboBA 90% localization confidence regions can be more than an order of magnitude smaller in area than those produced by BALROG.
Read the paper online at https://arxiv.org/abs/1909.03006.
The Fermi Gamma-ray Burst Monitor receives positive senior review results.
The Fermi 2019 Senior Review (SR) results have been released and the Fermi mission, including operations of the Gamma-Ray Burst Monitor (GBM), have been extended into 2022. Led by a team at NASA's Marshall Space Flight Center and the University of Alabama in Huntsville, GBM is currently the most prolific detector of transient astrophysical gamma-rays in the sky. The unique, full-sky observational capability of GBM was lauded and Fermi's scientific merit expectations were directly tied to GBM's multi-messenger observations with the Laser Interferometer Gravity Wave Observatory (LIGO) and other gravitational wave observatories. The Fermi Mission was also invited to submit another extended mission proposal for the 2022 SR cycle.
The full astrophysics Senior Review report can be found at: https://science.nasa.gov/astrophysics/2019-senior-review-operating-missions
Chandra's 20th Anniversary!
In 2019, NASA's Chandra X-ray Observatory celebrates its 20th year in space exploring the extreme universe.
Listen to a Public Radio Hour special on Chandra featuring Marshall scientists, Dr. Martin Weisskopf and Dr. Jessica Gaskin, as they join historian Brian Odom to talk about Chandra's discoveries. Just click on the link below.
Marshall X-ray optics will map the X-ray universe.
Scientists and technicians at the Marshall Space Flight Center (MSFC) have designed and fabricated eight Astronomical Roentgen Telescope - X-ray Concentrator (ART-XC) X-ray optics modules that have been launched into space as part of the Spectrum-Roentgen-Gamma (SRG or Spectr-RG observatory) mission. The purpose of this mission is to study the Universe's X-ray range of electromagnetic radiation and create a map of the X-ray Universe including large clusters of galaxies and active galactic nuclei. The SRG mission successfully launched from the Baikonur Cosmodrome on July 13, 2019.
The SRG mission is a Russian-led X-ray astrophysical observatory that carries two, co-aligned, X-ray telescope systems. The extended Roentgen Survey with an Imaging Telescope Array (eROSITA) is the German-led primary instrument for the mission and is a 7-module X-ray telescope system that operates in the 0.2 - 10 KeV band. The complementary instrument is the Astronomical Roentgen Telescope – X-ray Concentrator (ART-XC). This instrument is a seven module X-ray telescope system that operates in the 4-30 KeV energy range.
Marshall Space Flight Center designed and fabricated the seven (and one spare) co-aligned X-ray mirror modules making up the ART-XC telescope. Each module is composed of 28 concentric grazing-incidence mirror shells made using the same electroform-nickel replication process developed at MSFC for numerous space astrophysics and ground-based research applications.
You can learn more about the SRG mission by clicking on the following sites:
LISA Pathfinder sheds new light on interplanetary dust.
Researchers examining LISA Pathfinder data have been able to detect tiny impacts from cosmic dust, identify where the dust came from, and reveal clues to their origin. Read the full article from physicsworld to find out about cosmic dust and the search for gravitational waves.