FRB Source Located – Fast radio bursts (FRBs) are powerful flashes of radio energy that last only milliseconds, and what causes them is not understood. Some of them repeat from the same source, but many do not. A research team led by scientists at Chalmers University of Technology and the University of Amsterdam linked up twelve radiotelescope antennas around the world to obtain extreme location precision on one FRB repeater. They found it originates from a globular star cluster orbiting around the nearby galaxy M81, only 12 million light-years away. There are hints that FRBs are produced by magnetars, neutron stars with powerful magnetic fields, which are almost always found in clusters of young massive stars. Finding an FRB in a globular cluster of old, less massive stars was a surprise. If the radio source is a magnetar, it likely formed by the rare process of an old white dwarf star accreting mass and collapsing to a neutron star, rather than the more common collapse of a young massive star. Another surprise from the new observations is that the radio bursts flicker in brightness extremely quickly (tiny fractions of a microsecond), so by the limitations of the speed of light, the flickers must be produced in a region smaller than a sports field.
Pulsar Particle Beam – Scientists at Stanford University found that a pulsar designated PSR J2030+4415 emits a beam of matter and antimatter particles about seven light-years long. The pulsar is a spinning neutron star about ten miles across with a strong magnetic field. It’s located about 1,600 light-years away and is spinning about three times per second. Objects like this pulsar may help solve a mystery astronomers have long been puzzled by. Instruments like the International Space Station’s Alpha-Magnetic Spectrometer have long registered that Earth encounters an excess of positrons, the antimatter version of the electron. Astronomers believe that the magnetic field in the stellar wind of this pulsar has connected with the interstellar magnetic field, allowing its electrons and positrons to escape out into the galaxy. The beam of particles is this leakage, and it was imaged in X-rays that were given off by the fast-moving particles.
Exoplanet Atmosphere – Astronomers at MIT made the first extensive study of the atmosphere on the night side of an exoplanet. Their observations were made using a spectrograph on the Hubble Space Telescope over two full revolutions of the planet. Designated WASP-121b, the planet is tidally locked, meaning one side permanently faces the star. The gas giant orbits so close to its star that its year is only 30 hours long, and everywhere is extremely hot, between about 4,000 to 5,800 degrees Fahrenheit on the day side, while the night side stays between about 2,200 to 2,800 degrees Fahrenheit. Curiously, the temperature rises with increasing altitude on the day side, but the temperature drops with increasing altitude on the night side. The study tracked water in the atmosphere through a cycle that differs vastly from the Earth’s water cycle. WASP-121b’s water vapor on the day side is broken into hydrogen and oxygen by the high temperature, and those gases are transported by high winds to the night side, where they recombine to form water vapor, which is then transported back to the day side. These high winds likely reach up to 11,000 miles per hour. Iron, titanium, and corundum likely go through a cycle of liquid and vapor between day and night sides, so it might rain molten iron or liquid rubies (a form of corundum) on the night side. However, neither titanium nor aluminum were detected spectrographically and likely means that those two elements occur too deep in the atmosphere to be detected by these observations. The astronomers in this study plan to use the James Webb Space Telescope to repeat these observations, but with much greater spectrographic sensitivity to gases in the atmosphere.
Misaligned Black Hole – The binary star system known as MAXI J1820+070 consists of a black hole and an ordinary star orbiting each other. A new study of the system by researchers at the University of Turku found that the black hole’s axis of rotation is misaligned with the axis of the binary orbit by more than 40 degrees. The misalignment was surprising because many theories of black hole formation and binary star evolution have these axes aligned.
Giant Shock Waves – When clusters of galaxies collide, they form giant shock waves. Using the MeerKAT radiotelescope array in South Africa, a team of astronomers at the University of Hamburg made the most detailed image of the largest pair of known shock waves, which lie in the merged cluster of galaxies known as Abell 3667. The shocks were found to be more complex than previously thought. They contain filaments that follow the shock’s magnetic field lines and regions where electrons are accelerated to near-light speed. The shocks are moving through the cluster at more than 900 miles per second. The main shock is 6.5 million light-years long.
Galaxy Collision – The European Space Agency’s GAIA space telescope measures the properties of more than a billion stars, including their three-dimensional positions and motions. A team of astronomers at the Max Planck Institute for Astronomy searched the latest GAIA data release for evidence of small galaxies that were absorbed by our Milky Way, encoded in groups of stars with similar properties and motions. They observed five known galaxy mergers, but found a new one as well. The team is calling this merged galaxy Pontus, a mythological child of Gaia. The Pontus collision is estimated to have occurred between eight and ten billion years ago.
New Radio Image – A team of astronomers at the Netherlands Institute for Radio Astronomy created a detailed radio image of more than a quarter of the northern sky, using the LOFAR radiotelescope array, which extends across Europe. The image contains about a million objects never pictured before by any telescope, and nearly four million objects not seen before in radio wavelengths. A large number of the objects in the image are very distant galaxies. A small number are flaring stars in our own galaxy.
AGN Structure Confirmed – Astronomers believe that all varieties of active galactic nuclei (AGNs) have essentially the same supermassive black hole structure at their core. They can appear different based on the amount of material falling into their central black hole, or if parts are obscured by dust from the angle they’re viewed. AGNs have a central supermassive black hole, surrounded by an accretion disk, followed by a ring of hot gas, a fast-moving gas region, a dust ring and finally a region of slower-moving gas. To confirm this model, astronomers at Leiden University used infrared interferometry to observe the AGN in galaxy M77, which is thought to have its inner parts obscured by the dust ring. Observations using interferometry obtain high resolution of their subject, while infrared light penetrates dust. Data from the four Very Large Telescopes in Chile were combined for the interferometry, while data from the Atacama Large Millimeter/submillimeter Array and the Very Long Baseline Array were also used to penetrate the dust. The study confirmed what was expected to be hidden by the dust. The astronomers plan to use the same techniques to confirm the structure of other AGNs.
Galaxy Center Strands – Using MeerKAT radiotelescope array, scientists at Northwestern University and Oxford created the most detailed mosaic radio image of the Milky Way’s center. It showed almost 1,000 apparent strands covering an area about 150 light-years across. About 100 such strands have been known for over 40 years, but the new higher resolution image showed far more. The strands are believed to be cosmic ray electrons moving along magnetic lines at near the speed of light. Properties of the strands, such as magnetism and distribution of lengths, will be forthcoming in another paper based on this mosaic.
Magnetic Lines Imaged – Astronomers at Stanford imaged the magnetic field lines that interstellar gas follows as it flows toward a supermassive black hole at the center of a nearby galaxy. The team used infrared and radio images of the barred spiral galaxy NGC 1097, located about 45 million light-years away in Fornax. They were able to discern the field lines by carefully observing the light’s polarization in these images. Strong magnetic fields tend to align dust grains, which polarizes the light they encounter.
Large Molecule Found – Using the ALMA radiotelescope array in Chile, astronomers at Leiden Observatory found for the first time dimethyl ether in a planet-forming disk. At nine constituent atoms, it is the largest molecule yet found in such a disk. This disk surrounds the young star known as IRS 48, which is located 444 light-years away in Ophiuchus. This disk is unusual in that it contains a “dust-trap” where millimeter-sized grains seem to collect and grow. Heating from the young star probably freed the dimethyl ether from ice coatings on the dust. Dimethyl ether is considered a building block to form even larger organic molecules.
Binary Star Disks – A team led by scientists at the University of Manchester observed disks of gas and dust around a young binary star. There is a disk surrounding each component star and a third around the pair as a whole. All the disks could form planets. The disk about the pair has a spiral structure and is dropping material into the individual disks. The binary is known as SVS 13 and is located about 980 light-years away in the Perseus molecular cloud. Observations from two radiotelescope arrays were used, including decades of archived data. Almost 30 different molecules were identified in the system. The two stars are so close that they appear as one in optical observations.
Lunar Glass Globules – The Chinese Yutu-2 lunar rover discovered several centimeter-plus-sized translucent glass globules on the lunar surface of the Moon’s far side, where the rover continues to explore. Another possible pair was seen poorly at a distance. Smaller or opaque glass globules have been found on the Moon previously, but these new ones are unique. They are believed to have formed from molten iron-poor surface material splashed out of a long-ago meteor impact on the Moon.
Lunar Sample Being Opened – NASA kept some of the lunar rocks and soil retrieved by the Apollo astronauts untouched for more than 50 years, presuming that progress in instrumentation would allow more advanced science on these specimens when finally opened. One of the last of these preserved samples is being unsealed in hopes of learning more about what to expect when the Artemis missions bring more material back from the Moon over the next few years. The sample, known as ANGSA 73001, was brought back by Apollo 17 in 1972. It was collected by driving a tube into the lunar surface and has been tightly sealed and temperature controlled since. It should contain volatiles, material that evaporates when warmed, which will be captured and analyzed when the sample is opened.