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| Open AccessThe diffuse gamma-ray flux from clusters of galaxies
The origin of the diffuse gamma-ray background (DGRB) is unknown. Here, the authors show that the integrated gamma-ray flux from clusters can contribute up to 100% of the DGRB flux observed by Fermi-LAT above 100 GeV.
- Saqib Hussain
- , Rafael Alves Batista
- & Klaus Dolag
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| Open AccessA wind environment and Lorentz factors of tens explain gamma-ray bursts X-ray plateau
The origin of the plateau observed in the early X-ray light curves of gamma ray bursts (GRBs) is debated. Here, the authors show that the observed plateau can be explained within the classical GRB model by considering expanding shell with initial Lorentz factor of a few tens.
- Hüsne Dereli-Bégué
- , Asaf Pe’er
- & Maria G. Dainotti
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| Open AccessRepeating fast radio burst 20201124A originates from a magnetar/Be star binary
Fast radio bursts (FRBs) are bright millisecond or shorter duration transient events. Here, the authors propose that FRB 20201124A comes from a binary system of a magnetar and a Be star with a decretion disk.
- F. Y. Wang
- , G. Q. Zhang
- & K. S. Cheng
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| Open AccessThe supernova remnant SN 1006 as a Galactic particle accelerator
It is known that cosmic rays could be accelerated by shock waves in supernova (SN) remnants. Here, the authors show that SN 1006 remnant is an efficient source of cosmic rays, providing observational support for the quasi-parallel acceleration mechanism.
- Roberta Giuffrida
- , Marco Miceli
- & Giovanni Peres
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| Open AccessSearching for ultra-light bosons and constraining black hole spin distributions with stellar tidal disruption events
Stellar tidal disruption events (TDEs) occur when stars pass close enough to supermassive black holes. Here, the authors show that future searches TDEs have potential to uncover the existence of ultralight bosons.
- Peizhi Du
- , Daniel Egaña-Ugrinovic
- & Rosalba Perna
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| Open AccessA GeV-TeV particle component and the barrier of cosmic-ray sea in the Central Molecular Zone
Galactic center is one of the most important cosmic-ray sources. Here, the authors show GeV-TeV cosmic ray density in the central molecular zone is lower than the cosmic ray sea component, suggesting presence of high energy particle accelerator at the galactic center and existence of barrier.
- Xiaoyuan Huang
- , Qiang Yuan
- & Yi-Zhong Fan
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| Open AccessSoft gamma rays from low accreting supermassive black holes and connection to energetic neutrinos
The origins of the soft gamma-ray and high-energy neutrino backgrounds remain unknown. Here, the authors show radiatively inefficient accretion flows of low-luminosity active galactic nuclei can produce the soft gamma ray and high energy neutrino backgrounds simultaneously.
- Shigeo S. Kimura
- , Kohta Murase
- & Péter Mészáros
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| Open AccessSpectral index-flux relation for investigating the origins of steep decay in γ-ray bursts
Gamma ray bursts (GRB) are transient events releasing large amount of energy. Here, the authors show a relation between the spectral index and the flux, which allows further investigation of the origin of steep decay in GRBs.
- Samuele Ronchini
- , Gor Oganesyan
- & Om Sharan Salafia
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| Open AccessInsight-HXMT observations of jet-like corona in a black hole X-ray binary MAXI J1820+070
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
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Matters Arising
| Open AccessRapid 14C excursion at 3372-3371 BCE not observed at two different locations
- A. J. Timothy Jull
- , Irina P. Panyushkina
- & Willy Tegel
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| Open AccessX-ray flares from the stellar tidal disruption by a candidate supermassive black hole binary
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
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| Open AccessPowerful extragalactic jets dissipate their kinetic energy far from the central black hole
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
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| Open AccessGamma-ray flares from relativistic magnetic reconnection in the jet of the quasar 3C 279
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
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| Open AccessMeasuring the Hubble constant with a sample of kilonovae
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
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| Open AccessGravitational-wave asteroseismology with fundamental modes from compact binary inspirals
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
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| Open AccessEvolving parsec-scale radio structure in the most distant blazar known
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
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| Open AccessThe photospheric origin of the Yonetoku relation in gamma-ray bursts
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
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| Open AccessA 34.5 day quasi-periodic oscillation in γ-ray emission from the blazar PKS 2247–131
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
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Article
| Open AccessA luminous blue kilonova and an off-axis jet from a compact binary merger at z = 0.1341
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
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| Open AccessInfused ice can multiply IceCube’s sensitivity
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
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| Open AccessA peculiar low-luminosity short gamma-ray burst from a double neutron star merger progenitor
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
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Article
| Open AccessA circular white-light flare with impulsive and gradual white-light kernels
White-light flares are rare solar events entailing emission in the optical continuum. Here, the authors report a nearly circular white-light flare observed on March 10th 2015 that contains simultaneously both impulsive and gradual white-light kernels.
- Q. Hao
- , K. Yang
- & Z. Li
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| Open AccessA galactic microquasar mimicking winged radio galaxies
Winged radio galaxies possess wing features detectable at radio wavelengths, yet the physical interpretation of such extragalactic radio sources remains elusive. Here, the authors report the observation of a downsized Z-shaped radio emission from the Galactic microquasar GRS 1758-258, shedding light on the formation of wings in radio galaxies given its strongly reminiscent winged morphology.
- Josep Martí
- , Pedro L. Luque-Escamilla
- & Josep M. Paredes
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| Open AccessA rapid cosmic-ray increase in BC 3372–3371 from ancient buried tree rings in China
14C can be absorbed by trees as a result of the interaction of cosmic rays produced by high-energy phenomena with the Earth’s atmosphere. Here, the authors observe a rapid increase of 14C in an ancient buried tree from BC 3372 to BC 3371, and suggest that it could originate from a large solar proton event.
- F. Y. Wang
- , H. Yu
- & K. S. Cheng
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| Open AccessGravitational-wave localization alone can probe origin of stellar-mass black hole mergers
Binary black hole mergers have recently been observed through the detection of gravitational wave signatures. The authors demonstrate that their association with active galactic nuclei can be made through a statistical spatial correlation.
- I. Bartos
- , Z. Haiman
- & S. Marka
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| Open AccessFormation of the first three gravitational-wave observations through isolated binary evolution
Advanced LIGO has detected gravitational waves from two binary black hole mergers, plus a merger candidate. Here the authors use the COMPAS code to show that all three events can be explained by a single evolutionary channel via a common envelope phase, and characterize the progenitor metallicity and masses.
- Simon Stevenson
- , Alejandro Vigna-Gómez
- & Selma E. de Mink
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| Open AccessThe Macronova in GRB 050709 and the GRB-macronova connection
A macronova is a clear signature that a short gamma-ray burst has been emitted by a compact-binary merger, but evidence of these events is so far scarce. Here, the authors report signs of a macronova in the optical afterglow of GRB050709, and find similar evidence in other three short bursts.
- Zhi-Ping Jin
- , Kenta Hotokezaka
- & Tsvi Piran
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| Open AccessMultiradionuclide evidence for the solar origin of the cosmic-ray events of AD 774/5 and 993/4
Natural spikes in radiocarbon have been identified at AD 774/5 and 993/4 and attributed to exceptional cosmic-ray events, although the cause remains uncertain. Here, the authors analyse records recovered from ice cores and suggest these spikes originated from extreme solar particle events.
- Florian Mekhaldi
- , Raimund Muscheler
- & Thomas E. Woodruff
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Discovery of X-ray pulsations from a massive star
Optical light from many stars is known to pulsate and degenerate objects, like neutron stars, are known to emit pulses of X-rays, but X-ray pulsations have yet to be associated with non-degenerate objects. Here, Oskinova et al. find X-ray pulsations from a non-degenerate object: the massive B-type star ξ1CMa.
- Lidia M. Oskinova
- , Yael Nazé
- & Wolf-Rainer Hamann
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Ultra-high-energy cosmic ray acceleration in engine-driven relativistic supernovae
The origin of the highest energy cosmic rays is still unknown. Here, Chakraborti and colleagues show that a recently discovered sub-population of type Ibc supernovae with mildly relativistic outflows can satisfy all required characteristics for an ultra-high-energy cosmic ray source.
- S. Chakraborti
- , A. Ray
- & P. Chandra