Astronomy and astrophysics

Analysis of the pulse profile of a fast radio burst showed sub-second periodicity, providing evidence for a neutron-star origin of the event and favouring emission arising from the magnetosphere.

 Rare, converging cold flows gave birth to the massive black holes that were the seeds of the first quasars.

Lyman-α absorption observations from the Las Campanas Observatory are used to find a population of ultraviolet-dim protoclusters that contain few galaxies compared with their analogues in cosmological simulations.

The physics of dense matter extracted from neutron star collision data is demonstrated to be consistent with information obtained from heavy-ion collisions, and analyses incorporating both data sources as well as information from nuclear theory provide new constraints for neutron star matter.

A repeating fast radio burst co-located with a persistent radio source and associated with a dwarf host galaxy of a high star-formation rate has been detected.

The highlights of a wide range of studies using data from the Chandra X-ray Observatory and the X-ray Multi-Mirror Mission (XMM-Newton) are reviewed.

By evolving spatially resolved distributions of thermal and non-thermal electrons in a solar flare in a large coronal volume, it is shown that nearly all electrons experienced a prominent acceleration.

Binarity and multiplicity in general strongly affect the properties of emerging stars, as well as the physical and chemical structures of protoplanetary disks and therefore potentially any emerging planetary systems.

The dark-matter-free dwarf galaxies DF2 and DF4 in the NGC 1052 group probably formed together in the aftermath of a single bullet-dwarf collision around eight billion years ago.

Spectroscopy of a gravitationally lensed galaxy at a redshift of 2.7 with spatially resolved maps of two foreground damped Lyman α systems indicates a vast mass of neutral hydrogen gas, consistent with a star-forming region.

Novae are caused by runaway thermonuclear burning in the hydrogen-rich envelopes of accreting white dwarfs, which leads to a rapid expansion of the envelope and the ejection of most of its mass^1,2. Theory has predicted the existence of a ‘fireball’ phase following directly on from the runaway fusion, which should be observable as a short, bright and soft X-ray flash before the nova becomes visible in the optical^3–5. Here we report observations of a bright and soft X-ray flash associated with the classical Galactic nova YZ Reticuli 11 h before its 9 mag optical brightening. No X-ray source was detected 4 h before and after the event, constraining the duration of the flash to shorter than 8 h. In agreement with theoretical predictions^4,6–8, the source’s spectral shape is consistent with a black-body of 3.27^+0.11_−0.33 × 10⁵ K (28.2^+0.9_−2.8 eV), or a white dwarf atmosphere, radiating at the Eddington luminosity, with a photosphere that is only slightly larger than a typical white dwarf.

A study reporting optical and near-infrared observations of quasars at redshifts 5.8–6.6 shows that about half have strong winds, up to 17% the speed of light, suppressing black-hole growth.

ZTF J1406+1222 is a wide hierarchical triple system that hosts a low-metallicity subdwarf star and a ‘black widow’ millisecond pulsar that has a highly varying optical flux and a 62-minute period.

Dynamical simulations of the early Solar System show that the giant planets’ instability was triggered by the dispersal of the Sun’s gaseous disk, constrained by astronomical observations to be a few to ten million years after the birth of the Solar System.

The identification and characterization of rapid bursts in three accreting white dwarfs have shown that magnetically confined thermonuclear runaways resembling type-I X-ray bursts may occur in the surface layers of white dwarf atmospheres.

An unusual ultraviolet compact object associated with a dusty starburst has been observed at a redshift of about 7.2, with a luminosity that falls between that of quasars and galaxies, possibly in transition between the two. 

Analysis is presented that indicates that there is strong evidence that SiO or Mg, the major constituents of silicate condensates, must be present in gaseous form in the atmosphere of ultra-hot Jupiter WASP-178b.

A massive star at a redshift of 6.2, corresponding to 900 million years after the Big Bang, is magnified greatly by lensing of the foreground galaxy cluster WH0137–08.

A sample of approximately 250,000 subgiant stars enables an alternative view of the Milky Way’s assembly history, especially the early formation history of the old disk and halo.

The accretion disk environments surrounding active galactic nuclei are potential locations where there is an excess of eccentric mergers of large black holes, which have different spin–orbit tilts compared with circular mergers.

A persistent, blue-shifted absorption feature is reported in time-resolved UV spectroscopy of the neutron star binary Swift J1858.6-0814, revealing a warm, moderately ionized component in the accretion disk that is wind driven from this system.

The fast radio burst FRB 20200120E is shown to originate from a globular cluster in the galaxy M81, and may be a collapsed white dwarf or a merged compact binary star system.

Mid-infrared observations of the dusty structures of the galaxy NGC 1068 support the unified model of active galactic nuclei.

An X-ray source is detected at the expected position of the white dwarf star G29–38, which enables the calculation of the accretion rate of planetary material without using stellar atmosphere models.

Measurement of the cosmic microwave background temperature using H₂O absorption at a redshift of 6.34 is reported, the results of which were consistent with those from standard ΛCDM cosmology.

Analysis of archival low-frequency radio data from the Murchison Widefield Array reveals a periodic transient with an unusual periodicity of 18.18 min, the source of which is localized to our Galaxy and could be an ultra-long-period magnetar.

Optical observations with a linear resolution of a few parsecs show that the outflow from the central black hole in the low-mass galaxy Henize 2-10 triggered a round of star formation.

Three-dimensional analysis of the solar neighbourhood shows that nearly all star-forming regions near the Sun lie on the surface of the Local Bubble, which was inflated by supernovae about 14 million years ago.

Observations of the supernova SN 2019hgp, identified about a day after its explosion, show that it occurred within a nebula of carbon, oxygen and neon, and was probably the explosion of a massive WC/WO star.

An analysis of Zeeman measurements reveals that the reduction of magnetic flux relative to mass, which is necessary for star formation, seems to have occurred earlier than previously thought.

Observations of a stellar stream below the metallicity floor for a disrupted globular cluster are described.

Two very-high-frequency quasi-periodic oscillations (at 2,132 Hz and 4,250 Hz) are detected within the initial hard spike of a magnetar giant flare originating from the galaxy NGC 253, and detailed temporal and spectral analyses are performed.

Using a gravitational-wave detector to  listen for dark matter signatures, a direct search for scalar field dark matter was conducted and new upper limits are set on the coupling constants.

A direct imaging study demonstrates the existence of a giant planet in a wide orbit around the high-mass b Centauri binary system, and uses measurements of the orbital properties to discuss its formation mechanism.

A carbon monoxide gas ring co-orbiting with dusty debris is observed in the outer terrestrial planet region of the star HD 172555, which indicates that a planetary-scale impact took place.

For FRB 121102, 1,652 burst events are detected over 47 days, with a peak burst rate of 122 per hour, a bimodal burst rate energy distribution, and no periodicity or quasi-periodicity.

The authors show not only that planetary bodies around white dwarfs can survive but also that more than half of white dwarfs might have Jovian planetary companions.

Two serendipitously detected dust-obscured galaxies are reported at z = 6.7 and 7.4, with estimates that such galaxies provide an additional 10–25% contribution to the total star formation rate density at z > 6.

The authors report 1.3 mm observations of dust emission from strongly lensed galaxies where star formation is quenched, demonstrating that gas depletion is responsible for the cessation of star formation in some high-redshift galaxies.

The diffuse, isotropic background of gamma rays comes mainly from star-forming galaxies, according to a physical model of gamma-ray emission.

The metallicity of the interstellar medium measured towards 25 stars relatively near the Sun shows large variations, suggesting that infalling pristine gas is not efficiently mixed in the interstellar medium.

An observed one-day difference between the peaks of emission of ultraviolet and optical light from the hot spot on GM Aurigae indicates that the hot spot has a radial density gradient.

The fast radio burst FRB 20180916B repeats with a periodicity of 16 days, and is now found to emit down to a frequency of 120 MHz, much lower than previously observed.

The results of site testing at a local summit near Lenghu Town in Qinghai Province on the Tibetan Plateau indicate that the site is suitable as an astronomical observing site.

One of the key predictions of general relativity, the bending of light around massive, compact objects, is observed for a supermassive black hole in the galaxy I Zwicky 1.

Observations of ¹³CO in the atmosphere of a young, accreting super-Jupiter indicate a ¹³C-rich atmosphere, which is attributed to the accretion of carbon from ices enriched in ¹³C through fractionation.

Observations of an extremely metal-poor star suggest that rapidly rotating massive stars with large magnetic fields were a source of r-process elements in the early Universe.

A binary star merger has produced a white dwarf with a spin period of under 7 minutes, a magnetic field of 600 to 900 million gauss and a radius only slightly larger than that of our Moon.

The Gaia database is used to identify stars from which astronomers on orbiting planets could see Earth transiting the Sun in the past, present and future.