Astronomy and astrophysics

  • Article
    | Open Access

    The photodissociation dynamics of small molecules in the vacuum ultraviolet range can have key implications for astrochemical modelling, but revealing such dynamical details is a challenging task. Here the authors, combining high resolution experimental techniques, provide a detailed description of the fragmentation dynamics of selected rotational levels of a predissociated Rydberg state of H2S.

    • Yarui Zhao
    • , Zijie Luo
    •  & Xueming Yang
  • Article
    | Open Access

    Photon bubble turbulence is an astrophysical phenomenon involving radiation transport. Here, the authors report analogous behavior in ultracold gas by observing signatures of photon bubble instabilities in Rb atoms trapped in a MOT.

    • R. Giampaoli
    • , João D. Rodrigues
    •  & J. T. Mendonça
  • Article
    | Open Access

    Three-body dissociation of water, producing one oxygen and two hydrogen atoms, has been difficult to investigate due to the lack of intense vacuum ultraviolet sources. Here, using a tunable free-electron laser, the authors obtain quantum yields for this channel showing that it is a possible route to prebiotic oxygen formation in interstellar environments.

    • Yao Chang
    • , Yong Yu
    •  & Xueming Yang
  • Article
    | Open Access

    Evolution of accretion disk and corona during outbursts in black hole binary systems is still unclear. Here, the authors show spectral analysis of MAXI J1820+070 and propose a scenario of a dynamical corona to explain the evolution of the reflection fraction observed by Insight-HXMT.

    • Bei You
    • , Yuoli Tuo
    •  & Yue Zhu
  • Article
    | Open Access

    Imaging of low-mass exoplanets can be achieved once the thermal background in the mid-infrared (MIR) wavelengths can be mitigated. Here, the authors present a ground-based MIR observing approach enabling imaging low-mass temperate exoplanets around nearby stars.

    • K. Wagner
    • , A. Boehle
    •  & T. de Zeeuw
  • Article
    | Open Access

    Magnetic reconnection and plasma turbulence occur in atmospheric and magnetized laboratory plasmas. Here the authors report evolution of magnetic islands and plasma turbulence in tokamak plasmas using high resolution 2D electron cyclotron emission diagnostics.

    • Minjun J. Choi
    • , Lāszlo Bardōczi
    •  & George McKee
  • Article
    | Open Access

    The discrepancy between the optical and X-ray properties of tidal disruption events (TDE) is an unresolved issue. Here, the authors show delayed X-ray brightening after the optical flare in TDE OGLE16aaa followed by several flux dips during the decay phase that could be explained by the presence of supermassive black hole binary or patchy obscuration.

    • Xinwen Shu
    • , Wenjie Zhang
    •  & Tinggui Wang
  • Article
    | Open Access

    The location of energy dissipation in powerful extragalactic jets is currently unknown. Here, the authors show that the more distant molecular torus is the dominant location for powerful jets using a diagnostic called the seed factor which is dependent only on observable quantities.

    • Adam Leah W. Harvey
    • , Markos Georganopoulos
    •  & Eileen T. Meyer
  • Article
    | Open Access

    Adaptive optics wavefront sensors need to be in a pupil plane and are insensitive to certain wavefront-error modes. The authors present a wavefront sensor based on a photonic lantern fibre-mode-converter and deep learning, which can be placed at the same focal plane accessing nondegenerate wavefront information and reconstructing the wavefront.

    • Barnaby R. M. Norris
    • , Jin Wei
    •  & Sergio G. Leon-Saval
  • Article
    | Open Access

    Blazars show variable non-thermal emission across the electromagnetic spectrum from radio waves to gamma rays. Here, the authors show blazar 3C 279 reveals a characteristic peak-in-peak variability pattern on time scales of minutes if particle acceleration is due to relativistic magnetic reconnection.

    • A. Shukla
    •  & K. Mannheim
  • Article
    | Open Access

    Kilonovae observations can be used to out constraints on the Hubble constant (H0). Here, the authors show H0 measurements by combining light curves of four short gamma-ray burts with GW170817 are about a factor of 2-3 more precise than the standard-siren measurements using only gravitational-waves.

    • Michael W. Coughlin
    • , Sarah Antier
    •  & Nandita Khetan
  • Article
    | Open Access

    Current models of Galactic chemical evolution under predict the phosphorus we observe in our Solar System. Here, the authors show the discovery of 15 phosphorus-rich stars with a peculiar abundance pattern that challenges the present stellar nucleosynthesis theoretical predictions, but which could explain the missing source of phosphorus in the Galaxy.

    • Thomas Masseron
    • , D. A. García-Hernández
    •  & Carlos Dafonte
  • Article
    | Open Access

    In this study, the authors investigate in the influence of atmospheric dust on the habitability of exoplanets. They find that atmospheric dust may postpone planetary water loss; for tidally locked planets in particular, dust can significantly widen the habitable zone by cooling the day side and warming the night side.

    • Ian A. Boutle
    • , Manoj Joshi
    •  & Krisztian Kohary
  • Article
    | Open Access

    Independently measuring the tidal deformability and the fundamental oscillation mode (fmode) frequency enables tests of gravity and the nature of compact binaries. Here, the authors constrain the f-mode frequencies of the companions of GW170817 from direct measurements, demonstrating gravitational wave asteroseismology with binary inspiral signals alone.

    • Geraint Pratten
    • , Patricia Schmidt
    •  & Tanja Hinderer
  • Article
    | Open Access

    Sulfur is abundant in the Universe, but the observed abundance ratio of SH to H2S doesn’t agree with astrochemical models. The authors measure product state-resolved translational energy spectra of photoproducts in a jet-cooled H2S beam as a function of wavelength, showing that SH yield is lower than assumed in the models.

    • Jiami Zhou
    • , Yarui Zhao
    •  & Xueming Yang
  • Article
    | Open Access

    Polycyclic aromatic hydrocarbons (PAHs) are present in the interstellar medium but their origin is unclear. Here the authors investigate large PAH formation from smaller PAHs in a plasma jet by mass-selective IR and UV laser spectroscopy, uncovering diacetylene radical addition as formation mechanism.

    • Alexander K. Lemmens
    • , Daniël B. Rap
    •  & Anouk M. Rijs
  • Article
    | Open Access

    High redshift blazars are efficient probes of supermassive black holes and their environment in the early Universe. Here the authors show measurements of polarised emission and proper motion in the blazar J0906+6930 (redshift of 5.47) characterised by a nascent jet embedded in and interacting with a dense medium.

    • Tao An
    • , Prashanth Mohan
    •  & Zhenya Zheng
  • Article
    | Open Access

    The formation of nucleobases can take place in extraterrestrial environments. Here the authors show the simultaneous synthesis of three purine nucleobases and three pyrimidine from interstellar ice analogues that suggest the evolution from molecular clouds to stars and planets provide suitable environment for nucleobase synthesis in space.

    • Yasuhiro Oba
    • , Yoshinori Takano
    •  & Akira Kouchi
  • Article
    | Open Access

    The ionisation fraction of protostellar jets is key to establish their true energetics. Here, the authors determine it in a jet from a high-mass young stellar object, using multi-wavelengths observations, confirming that the ionising mechanism giving rise to the radio emission originates from shocks.

    • R. Fedriani
    • , A. Caratti o Garatti
    •  & M. Hoare
  • Article
    | Open Access

    Interstellar magnetic fields determined from pulsar polarimetry in the GHz-band may be biased by mechanical-optical rotation in pulsars’ magnetospheres. Here the authors show how observations at sub-GHz frequencies can be used to resolve such a bias and determine pulsar rotation directions.

    • Renaud Gueroult
    • , Yuan Shi
    •  & Nathaniel J. Fisch
  • Article
    | Open Access

    Galaxy clusters contain vast amount of dark matter and baryonic matter. Here the authors show the observational detection of the anti-correlation of gas mass and stellar mass observables in the most massive galaxy clusters, indicating such clusters retain close to the cosmic mix of baryons and dark matter.

    • Arya Farahi
    • , Sarah L. Mulroy
    •  & Nobuhiro Okabe
  • Article
    | Open Access

    Yonetoku relation provides a diagnostic for the radiation mechanism in the prompt phase of gamma-ray burst (GRB) emission. Here, Ito et al. show the reproduction of this relation in 3D hydrodynamical simulations followed by radiative transfer calculations, which suggest the photospheric emission is the dominant component in the prompt phase of GRBs.

    • Hirotaka Ito
    • , Jin Matsumoto
    •  & Daisuke Yonetoku
  • Article
    | Open Access

    Sugars are known to form from the UV photoprocessing of ices under astrophysical conditions. Here, the authors report the detection of deoxyribose, the sugar of DNA, and other deoxysugars from the UV photoprocessing of H2O:CH3OH ice mixtures, which are compared with materials from carbonaceous meteorites.

    • Michel Nuevo
    • , George Cooper
    •  & Scott A. Sandford
  • Article
    | Open Access

    H2 roaming is associated with H3+ formation when certain organic molecules are exposed to strong laser fields. Here, the mechanistic details and time-resolved dynamics of H3+ formation from a series of alcohols were obtained and found that the product yield decreases as the carbon chain length increases.

    • Nagitha Ekanayake
    • , Travis Severt
    •  & Marcos Dantus
  • Article
    | Open Access

    The presence of magnetic fields in protostellar jets has been predicted theoretically, but its experimental confirmation has been elusive so far. Here, the authors report the detection of SiO line polarisation in the HH 211 protostellar jet, indicative of the onset of magnetic fields.

    • Chin-Fei Lee
    • , Hsiang-Chih Hwang
    •  & Paul. T. P Ho
  • Article
    | Open Access

    PKS 2247–131 is an active galaxy that has been emitting gamma-ray flares since October 2016. Here, the authors used data obtained with the Fermi Gamma-ray Space Telescope to find that PKS 2247–131 presents a relatively short, month-like flux oscillation at gamma-ray energies of 0.1–300 GeV.

    • Jianeng Zhou
    • , Zhongxiang Wang
    •  & Jujia Zhang
  • Article
    | Open Access

    A faint gamma-ray burst (GRB 170817A) has been recently detected in coincidence with the gravitational wave (GW) event GW 170817. Here, the authors report that another faint short GRB at a cosmological distance (GRB150101B) and its late time emission are analogous to the neutron star merger event GRB 170817A.

    • E. Troja
    • , G. Ryan
    •  & S. Veilleux
  • Article
    | Open Access

    Alumina is thought to be the main condensate to form in the gas outflow from oxygen-rich evolved stars. Here, the authors perform a condensation experiment with alumina in a low-gravity environment, and find spectroscopic evidence for a sharp feature at a wavelength of 13.55 μm.

    • Shinnosuke Ishizuka
    • , Yuki Kimura
    •  & Yuko Inatomi
  • Article
    | Open Access

    Tree rings retain information of sudden variations of ancient radiocarbon (14C) content, however the origin and exact timing of these events often remain uncertain. Here, the authors analyze a set of Arctic tree rings and link a rapid increase in 14C to a solar event that occurred during the spring of AD 774.

    • J. Uusitalo
    • , L. Arppe
    •  & M. Oinonen
  • Article
    | Open Access

    Observations of Jupiter’s magnetosphere provide opportunities to understand how magnetic fields interact with particles. Here, the authors report that the chorus wave power is increased in the vicinity of Europa and Ganymede. The generated waves are able to accelerate particles to very high energy.

    • Y. Y. Shprits
    • , J. D. Menietti
    •  & D. A. Gurnett
  • Article
    | Open Access

    It has been conjectured that gravity may emerge from an entropic force arising on a holographic screen due to its purportedly intrinsic thermodynamic properties. Here, the authors test this conjecture by demonstrating that this key assumption of entropic force is inconsistent with general relativity.

    • Zhi-Wei Wang
    •  & Samuel L. Braunstein
  • Article
    | Open Access

    The red supergiant VX Sagittarii is a strong emitter of H2O and SiO masers, however its mass loss dynamics are still poorly understood. Here, the authors present astrometrically registered, simultaneous maps of SiO and H2O maser regions, and provide observational evidence for a break in spherical symmetry between the SiO and H2O maser zone.

    • Dong-Hwan Yoon
    • , Se-Hyung Cho
    •  & Do-Young Byun
  • Article
    | Open Access

    In order to detect relic neutrinos in the vicinity of the Earth, quantitative knowledge of the gravitational clustering effects on cosmic relic neutrinos in the Milky Way is necessary. Here, the authors develop a computational method capable of yielding neutrino density profiles for different neutrino masses and phase space distributions in a single simulation.

    • Jue Zhang
    •  & Xin Zhang
  • Article
    | Open Access

    The IceCube Neutrino Observatory has been recording a flux of high-energy cosmic neutrinos since 2013. Here, the authors investigate the possibility of increasing its sensitivity by implementing wavelength shifting optics within IceCube’s drill holes.

    • Imre Bartos
    • , Zsuzsa Marka
    •  & Szabolcs Marka
  • Article
    | Open Access

    The Sun’s light stable isotopes compositions can help us understand how our solar system formed. Here, the authors find that solar C is depleted relative to bulk Earth indicating that the 13C enrichment of the terrestrial planets is from CO self-shielding or inheritance from the parent cloud.

    • James R. Lyons
    • , Ehsan Gharib-Nezhad
    •  & Thomas R. Ayres
  • Article
    | Open Access

    Exploring astrophysical turbulent effects in laboratory plasma is challenging due to high threshold values of relevant parameters, such as the magnetic Reynolds number. Here the authors demonstrate the turbulent dynamo effect at large magnetic Reynolds numbers in laser-generated magnetized plasma.

    • P. Tzeferacos
    • , A. Rigby
    •  & G. Gregori
  • Article
    | Open Access

    Pulsar timing arrays enable the search for the isotropic gravitational-wave (GW) background originating from super massive black hole binary populations, but impose a stringent upper limit on the GW characteristic amplitude. Here, the authors use Bayesian hierarchical modelling applied to a range of astrophysical scenarios to revisit the implications of this upper limit.

    • Hannah Middleton
    • , Siyuan Chen
    •  & Alberto Vecchio
  • Article
    | Open Access

    A short-duration gamma-ray burst was detected along with a double neutron start merger gravitational wave by LIGO-Virgo on August 17th 2017. Here, the authors show that the fluence and spectral peak energy of this event fall into the lower portion of the distribution of known short-duration gamma-ray bursts.

    • B.-B. Zhang
    • , B. Zhang
    •  & E.-W. Liang