Article
Astronomy & Astrophysics
Benoit Cerutti, Gwenael Giacinti
Summary: This study investigates the origin of knots in the inner radius of the Crab Nebula through large-scale three-dimensional plasma simulations. The formation of giant plasmoids is identified as a robust feature of pulsar wind termination shocks, which can provide a natural explanation for inner-ring knots in highly magnetized nebulae.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
J. R. Martinez, S. del Palacio, V Bosch-Ramon, G. E. Romero
Summary: This article investigates the interaction between the fast motion and stellar wind of runaway stars and their surrounding environment, and explores their potential as cosmic-ray accelerators and non-thermal emitters. The results of the study suggest that high-sensitivity observations in the radio band can be used to detect the non-thermal radiation associated with bow shocks from runaway stars.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
S. del Palacio, F. Garcia, M. De Becker, D. Altamirano, V. Bosch-Ramon, P. Benaglia, B. Marcote, G. E. Romero
Summary: This study focused on the non-thermal emission from a massive colliding-wind binary (CWB) system called Apep. By analyzing its hard X-ray spectrum, the researchers were able to break the degeneracy between relativistic particle population and magnetic field strength in the wind-collision region (WCR). The results provided important insights into the particle acceleration efficiency and magnetic field intensity in CWBs.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
M. Moutzouri, J. Mackey, C. Carrasco-Gonzalez, Y. Gong, R. Brose, D. Zargaryan, J. A. Toala, K. M. Menten, V. V. Gvaramadze, M. R. Rugel
Summary: Winds from massive stars are considered promising for investigating relativistic particle acceleration, with bow-shaped shocks observed at various wavelengths. This study focuses on the O4If star BD+43 degrees 3654 and NGC 7635, analyzing their radio emissions and finding non-thermal emission present. Modeling suggests that accelerated electrons at the wind termination shock contribute to the non-thermal radio emission.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Maxim Lyutikov
Summary: Magnetic explosions from magnetars are governed by the conservation of magnetic flux and reach a dynamic equilibrium with pre-flare winds before quietly propagating forward without generating powerful shock waves in the wind.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Daniel Iniguez-Pascual, Daniele Vigano, Diego F. Torres
Summary: In this study, the existing synchro-curvature radiation model is improved by better handling of particle injection and implementing a fast and accurate minimization technique. The results show that most of the detected X-ray radiation in high-energy pulsars is produced in a small fraction of their trajectory, and synchrotron radiation is significant for most of the gamma-ray pulsars detected. Additionally, J0357+3205 and J2055+2539 are suggested as MeV pulsar candidates based on the obtained results.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Shi-Jie Gao, Xiang-Dong Li
Summary: Helium white dwarfs (HeWDs) are formed from low-mass red giant stars that undergo binary interaction. The traditional relation between orbital period (P-orb) and HeWD mass (M-WD) is affected by wind mass-loss from red giants, which is higher in binary systems. Through calculations, it is found that tidally enhanced stellar wind (TEW) leads to a scatter in the traditional M-WD-P-orb relation. However, more observations of HeWD binaries in wide orbits are needed to test the TEW model and constrain the enhanced wind factor.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Maxim Barkov, V Bosch-Ramon
Summary: Using relativistic hydrodynamical simulations, we study the combined impact of stellar wind and orbital motion on the properties of high-mass microquasar jets. Our results show that the combined effects can induce relativistic jet disruption on scales of 1 AU.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Bo-Tao Zhu, Fang-Wu Lu, Bing Zhou, Li Zhang
Summary: This study investigates the nonthermal radiation properties of pulsar wind nebulae using a time-dependent model with particle advection and diffusion. The results show that particle transport processes can affect both the nebula flux and the spectrum of emitted radiation, with varying effects across different wavelength bands. The model is applied to three specific PWNe, where it is found that particle cooling processes are dominated by different mechanisms at different energy levels, and particle transport processes are mainly advection-dominated with potential slow diffusion in certain nebulae.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
V. Bosch-Ramon
Summary: The research suggests that the pulsar wind in LS 5039 is likely strongly anisotropic, requiring specific wind orientation and polarization numbers, or a low wind orientation. Alternatively, a cold baryon-dominated wind with high multiplicities can also be considered, but with low baryon-to-e(+/-) energy transfer efficiency. However, a strongly magnetized cold wind is seen as the most favorable option.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Bo-Tao Zhu, Fang-Wu Lu, Bing Zhou, Jun Fang, Li Zhang
Summary: This study investigates the radio and X-ray properties of both gamma-ray bursts and pulsar wind nebulae, and finds correlations between the two. The results show that they have the same or similar particle acceleration mechanisms and radiation processes, namely synchrotron radiation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
A. Feeney-Johansson, S. J. D. Purser, T. P. Ray, C. Carrasco-Gonzalez, A. Rodriguez-Kamenetzky, J. Eisloeffel, J. Lim, R. Galvan-Madrid, S. Lizano, L. F. Rodriguez, H. Shang, P. Ho, M. Hoare
Summary: Using radio observations from multiple telescopes, we obtained high-resolution images of the radio jets of two binary YSOs and found significant variability in the free-free emission, with the northern component of L1551 IRS 5 showing a nearly complete disappearance of this emission. The ionised mass-loss rates of the jets also exhibited significant changes over a timescale of approximately 20 years.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Paula Benaglia, Santiago del Palacio, Christopher Hales, Marcelo E. Colazo
Summary: The study conducted a deep radio-polarimetric observation of the stellar bow shock EB27 and found non-thermal radio emission influenced by the overall magnetic field. Although no linear polarization was detected in the bow shock, polarized emission was detected from two sources in the south. By modeling the radio emission, a better understanding of the magnetic field and injected power in relativistic electrons was achieved.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
E. Kefala, V. Bosch-Ramon
Summary: Using different semi-analytical tools, this study investigates the dynamics and high-energy radiation of a pulsar wind colliding with a stellar wind containing inhomogeneities. The results show that an inhomogeneous stellar wind can induce stochastic hour-timescale variations in the geometry of the interaction structure, leading to hour-scale variability in X-rays and gamma rays, with the largest variations occurring roughly once per orbit.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Barbara Ercolano, Giovanni Picogna, Kristina Monsch, Jeremy J. Drake, Thomas Preibisch
Summary: Young solar-type stars are strong X-ray emitters, with X-rays playing a crucial role in the thermodynamics and chemistry of circumstellar material and the atmospheric evolution of young planets. This paper presents model spectra based on observations from the Orion nebula cluster and provides new photoevaporation prescriptions for disc and planet population synthesis models. The models show that disc wind mass loss rates are controlled by stellar luminosity in the soft X-ray band, and predict a population of non-accreting transition discs not yet observed.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Huan Yu, Jun Fang, Peng Fei Zhang, Li Zhang
ASTRONOMY & ASTROPHYSICS
(2015)
Article
Astronomy & Astrophysics
Bo-Tao Zhu, Jun Fang, Li Zhang
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2015)
Article
Astronomy & Astrophysics
Huan Yu, Jun Fang, Peng Fei Zhang, Li Zhang
ASTRONOMY & ASTROPHYSICS
(2015)
Article
Astronomy & Astrophysics
Jun Fang, Huan Yu, Li Zhang
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2017)
Article
Astronomy & Astrophysics
Jun Fang, Huan Yu, Li Zhang
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2018)
Article
Astronomy & Astrophysics
Bo-Tao Zhu, Li Zhang, Jun Fang
ASTRONOMY & ASTROPHYSICS
(2018)
Article
Astronomy & Astrophysics
Chuyuan Yang, Siming Liu, Jun Fang, Hui Li
ASTRONOMY & ASTROPHYSICS
(2015)
Article
Astronomy & Astrophysics
Huan Yu, Jun Fang
RESEARCH IN ASTRONOMY AND ASTROPHYSICS
(2018)
Article
Astronomy & Astrophysics
Jun Fang, Jingwen Yan, Lu Wen, Chunyan Lu, Huan Yu
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2020)
Article
Astronomy & Astrophysics
Jun Fang, Lu Wen, Huan Yu, Songzhan Chen
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2020)
Article
Astronomy & Astrophysics
Bo-Tao Zhu, Fang-Wu Lu, Bing Zhou, Jun Fang, Li Zhang
Summary: This study investigates the radio and X-ray properties of both gamma-ray bursts and pulsar wind nebulae, and finds correlations between the two. The results show that they have the same or similar particle acceleration mechanisms and radiation processes, namely synchrotron radiation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Jun Fang, Qi Xia, Shiting Tian, Liancheng Zhou, Huan Yu
Summary: Non-relativistic quasi-parallel shocks have the potential to accelerate electrons, protons, and helium ions. A 1D particle-in-cell simulation of a non-relativistic quasi-parallel shock with a helium-to-proton number density ratio relevant to Galactic cosmic rays reveals that energetic protons and helium ions can excite waves upstream of the shock, leading to the scattering and gradual acceleration of charged particles. The downstream spectra of charged particles are thermal with a non-thermal tail, and a significant amount of kinetic energy is transferred to non-thermal protons and helium ions.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Keyao Wu, Liancheng Zhou, Yunlu Gong, Jun Fang
Summary: LHAASO J1908+0621 has been detected as a gamma-ray source emitting energies above 100 TeV, with a break appearing in the gamma-ray spectrum around 1 TeV. The properties of the source have been reanalyzed using 14 years of data from the Fermi-LAT. The results suggest that LHAASO J1908+0621 is associated with a pulsar wind nebula powered by the pulsar PSR J1907+0602, and gamma-rays with energy above 100 TeV are produced by electrons/positrons in the nebula via inverse Compton scattering.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Bo-Tao Zhu, Li Zhang, Jun Fang
ASTROPHYSICAL JOURNAL
(2019)