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Keywords = inverse Compton scattering

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18 pages, 2382 KiB  
Article
Bethe–Heitler Cascades and Hard Gamma-Ray Spectra in Flaring TeV Blazars: 1ES 0414009 and 1ES 1959650
by Samuel Victor Bernardo da Silva, Luiz Augusto Stuani Pereira and Rita de Cássia Dos Anjos
Universe 2025, 11(6), 177; https://doi.org/10.3390/universe11060177 - 31 May 2025
Viewed by 1453
Abstract
In this work, we present updated models of the spectral energy distributions (SEDs) for two high-frequency-peaked BL Lac objects (HBLs), that is, 1ES 0414+009 and 1ES 1959+650. The hard gamma-ray spectra observed during their flaring states suggest the presence of an additional emission [...] Read more.
In this work, we present updated models of the spectral energy distributions (SEDs) for two high-frequency-peaked BL Lac objects (HBLs), that is, 1ES 0414+009 and 1ES 1959+650. The hard gamma-ray spectra observed during their flaring states suggest the presence of an additional emission component beyond the standard synchrotron self-Compton (SSC) scenario. We explore the possibility that this hard gamma-ray emission arises from inverse Compton (IC) scattering by Bethe–Heitler pairs produced along the line of sight, pointing to a more complex high-energy emission mechanism in these sources. Full article
(This article belongs to the Special Issue 10th Anniversary of Universe: Galaxies and Their Black Holes)
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42 pages, 5853 KiB  
Review
Harnessing Ultra-Intense Long-Wave Infrared Lasers: New Frontiers in Fundamental and Applied Research
by Igor V. Pogorelsky and Mikhail N. Polyanskiy
Photonics 2025, 12(3), 221; https://doi.org/10.3390/photonics12030221 - 28 Feb 2025
Viewed by 1031 | Correction
Abstract
This review explores two main topics: the state-of-the-art and emerging capabilities of high-peak-power, ultrafast (picosecond and femtosecond) long-wave infrared (LWIR) laser technology based on CO2 gas laser amplifiers, and the current and advanced scientific applications of this laser class. The discussion is [...] Read more.
This review explores two main topics: the state-of-the-art and emerging capabilities of high-peak-power, ultrafast (picosecond and femtosecond) long-wave infrared (LWIR) laser technology based on CO2 gas laser amplifiers, and the current and advanced scientific applications of this laser class. The discussion is grounded in expertise gained at the Accelerator Test Facility (ATF) of Brookhaven National Laboratory (BNL), a leading center for ultrafast, high-power CO2 laser development and a National User Facility with a strong track record in high-intensity physics experiments. We begin by reviewing the status of 9–10 μm CO2 laser technology and its applications, before exploring potential breakthroughs, including the realization of 100 terawatt femtosecond pulses. These advancements will drive ongoing research in electron and ion acceleration in plasma, along with applications in secondary radiation sources and atmospheric energy transport. Throughout the review, we highlight how wavelength scaling of physical effects enhances the capabilities of ultra-intense lasers in the LWIR spectrum, expanding the frontiers of both fundamental and applied science. Full article
(This article belongs to the Special Issue High-Power Ultrafast Lasers: Development and Applications)
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13 pages, 324 KiB  
Article
Galactic Stellar Black Hole Binaries: Spin Effects on Jet Emissions of High-Energy Gamma-Rays
by Dimitrios Rarras, Theocharis Kosmas, Theodora Papavasileiou and Odysseas Kosmas
Particles 2024, 7(3), 792-804; https://doi.org/10.3390/particles7030046 - 3 Sep 2024
Cited by 2 | Viewed by 1755
Abstract
In the last few decades, galactic stellar black hole X-ray binary systems (BHXRBs) have aroused intense observational and theoretical research efforts specifically focusing on their multi-messenger emissions (radio waves, X-rays, γ-rays, neutrinos, etc.). In this work, we investigate jet emissions of high-energy [...] Read more.
In the last few decades, galactic stellar black hole X-ray binary systems (BHXRBs) have aroused intense observational and theoretical research efforts specifically focusing on their multi-messenger emissions (radio waves, X-rays, γ-rays, neutrinos, etc.). In this work, we investigate jet emissions of high-energy neutrinos and gamma-rays created through several hadronic and leptonic processes taking place within the jets. We pay special attention to the effect of the black hole’s spin (Kerr black holes) on the differential fluxes of photons originating from synchrotron emission and inverse Compton scattering and specifically on their absorption due to the accretion disk’s black-body radiation. The black hole’s spin (dimensionless spin parameter a*) enters into the calculations through the radius of the innermost circular orbit around the black hole, the RISCO parameter, assumed to be the inner radius of the accretion disk, which determines its optical depth τdisk. In our results, the differential photon fluxes after the absorption effect are depicted as a function of the photon energy in the range 1GeV E103GeV. It is worth noting that when the black holes’ spin (α*) increases, the differential photon flux becomes significantly lower. Full article
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10 pages, 1932 KiB  
Article
Simulation Study on Attosecond Inverse Compton Scattering Source from Laser Wakefield Acceleration with Near-Threshold Ionization Injection
by Aihua Deng, Yan Li, Yugan Weng, Zhiling Luo, Xitao Yu and Jiaolong Zeng
Appl. Sci. 2024, 14(17), 7749; https://doi.org/10.3390/app14177749 - 2 Sep 2024
Viewed by 1214
Abstract
We present the generation of attosecond gamma rays via inverse Compton scattering within the framework of laser wakefield acceleration through 2D Particle-In-Cell simulations. Utilizing the near-threshold ionization injection mechanism, an attosecond micro-bunched electron beam characterized by a comb-like current density profile can be [...] Read more.
We present the generation of attosecond gamma rays via inverse Compton scattering within the framework of laser wakefield acceleration through 2D Particle-In-Cell simulations. Utilizing the near-threshold ionization injection mechanism, an attosecond micro-bunched electron beam characterized by a comb-like current density profile can be achieved with a linearly polarized laser at an intensity of a0 = 1.5. The micro-bunched beam provides a beam energy of approximately 300 MeV and achieves a minimum relative energy spread of about 1.64% after undergoing 2 mm of acceleration. In the inverse Compton scattering scheme, these attosecond electron micro-bunches interact with the reflected driving laser pulse, resulting in the attosecond gamma-ray radiation exhibiting similar structures. Individual spatial-separated gamma-ray pulses exhibit a length of approximately 260–300 as, with a critical energy of 2.0 ± 0.2 MeV. The separated attosecond gamma-ray source owns a peak brilliance of ~1022 photons s−1 mm−2 mrad−2 0.1% BW. This brilliance is competitive in a laboratory for multi-MeV γ-ray sources with a laser intensity of I = 5 × 1018 W/cm2. Such attosecond gamma-ray radiation offers promising applications requiring ultrashort X-ray/gamma ray sources. Full article
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13 pages, 480 KiB  
Article
A Lepton–Hadron Model for the Multi-Wavelength Emission from Extreme High-Frequency Peaked BL Lacertae 1ES 1218+304
by Wenjing Dong, Qian Dong and Yonggang Zheng
Galaxies 2024, 12(1), 2; https://doi.org/10.3390/galaxies12010002 - 29 Dec 2023
Cited by 1 | Viewed by 2117
Abstract
We develop a lepton–hadron model for the possible origin of hard very high energy (VHE) spectra from a distant blazar. The model includes synchrotron self-Compton (SSC) and hadronic components. The lepton components include synchrotron radiation and inverse Compton scattering of relativistic electrons. For [...] Read more.
We develop a lepton–hadron model for the possible origin of hard very high energy (VHE) spectra from a distant blazar. The model includes synchrotron self-Compton (SSC) and hadronic components. The lepton components include synchrotron radiation and inverse Compton scattering of relativistic electrons. For the hadronic components, we consider proton synchrotron radiation and investigate the interaction of protons with the synchrotron emission soft photons or cosmic microwave background (CMB) photons. Upon adopting the parametrization of the observed spectrum of 1ES 1218+304, we obtain the following results: (1) the model is able to match the spectral energy distribution of 1ES 1218+304; (2) we find that in Ep10101017eV, the π0γ-ray process contributes the majority of the secondary photons; and (3) the interaction of protons with the low-energy photons may occur in or outside the jet. Full article
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11 pages, 6072 KiB  
Article
Overview and Commissioning Status of the UCLA MITHRA Facility
by Oliver Williams, Atsushi Fukasawa, Yusuke Sakai, Gerard Andonian, Fabio Bosco, Martina Carillo, Pratik Manwani, Sean O’Tool, Jessica Pan, Monika Yadav and James Rosenzweig
Instruments 2023, 7(4), 54; https://doi.org/10.3390/instruments7040054 - 14 Dec 2023
Cited by 1 | Viewed by 2052
Abstract
Presented here are the first results of commissioning of the S-Band hybrid photoinjector and laser systems at the new accelerator and light source facility, MITHRA, at UCLA. The radiation bunker and capabilities of the facility are described with motivation for detailed measurement of [...] Read more.
Presented here are the first results of commissioning of the S-Band hybrid photoinjector and laser systems at the new accelerator and light source facility, MITHRA, at UCLA. The radiation bunker and capabilities of the facility are described with motivation for detailed measurement of beam parameters explained. Following thorough characterization of the photoinjector, a 1.5 m linac is to be installed and experiments up to 30 MeV will begin. These will include experiments in basic plasma physics, space plasma, terahertz production in dielectric structures, and inverse Compton scattering and applications for the X-rays produced. Full article
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11 pages, 1252 KiB  
Communication
On the Possible Asymmetry in Gamma Rays from Andromeda Due to Inverse Compton Scattering of Star Light on Electrons from Dark Matter Annihilation
by Konstantin Belotsky and Maxim Solovyov
Galaxies 2023, 11(6), 109; https://doi.org/10.3390/galaxies11060109 - 7 Nov 2023
Viewed by 1533
Abstract
Dark matter is a popular candidate to a new source of primary-charged particles, especially positrons in cosmic rays, which are proposed to account for observable anomalies. While this hypothesis of decaying or annihilating DM is mostly applied for our Galaxy, it could possibly [...] Read more.
Dark matter is a popular candidate to a new source of primary-charged particles, especially positrons in cosmic rays, which are proposed to account for observable anomalies. While this hypothesis of decaying or annihilating DM is mostly applied for our Galaxy, it could possibly lead to some interesting phenomena when applied for the other ones. In this work, we look into the hypothetical asymmetry in gamma radiation from the upper and lower hemisphere of the dark matter halo of the Andromeda galaxy due to inverse Compton scattering of starlight on the DM-produced electrons and positrons. While our 2D toy model raises expectations for the possible effect, a more complex approach gives negligible effect for the dark halo case, but shows some prospects for a dark disk model. Full article
(This article belongs to the Special Issue Galactic Structure and Dynamics)
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10 pages, 253 KiB  
Review
Solving the Mystery of Fast Radio Bursts: A Detective’s Approach
by Bing Zhang
Universe 2023, 9(8), 375; https://doi.org/10.3390/universe9080375 - 18 Aug 2023
Cited by 3 | Viewed by 2031
Abstract
Fast radio bursts (FRBs) are still a mystery in contemporary astrophysics. Unlike many other astronomical objects whose basic physical mechanism is already identified and the research on which focuses mainly on refining details, FRBs are still largely unknown regarding their source(s) and radiation [...] Read more.
Fast radio bursts (FRBs) are still a mystery in contemporary astrophysics. Unlike many other astronomical objects whose basic physical mechanism is already identified and the research on which focuses mainly on refining details, FRBs are still largely unknown regarding their source(s) and radiation mechanism(s). To make progress in the field, a “top-down” or “detective’s approach” is desirable. I will summarize how some key observational facts have narrowed down the options to interpret FRBs and show that at least some FRBs are produced from the magnetospheres of highly magnetized neutron stars (or magnetars). I will also argue that the current data seem to favor a type of coherent inverse Compton scattering process by relativistic particle bunches off a low-frequency wave propagating in the magnetosphere. This brief contribution is a shorter version of an extended review to be published in Reviews of Modern Physics, and it was written as a tribute to the 80th anniversary of Remo Ruffini. Full article
(This article belongs to the Special Issue Remo Ruffini Festschrift)
16 pages, 589 KiB  
Article
Studying the Spectral Energy Distributions Emanating from Regular Galactic XRBs
by Theodora Papavasileiou, Odysseas Kosmas and Ioannis Sinatkas
Universe 2023, 9(7), 312; https://doi.org/10.3390/universe9070312 - 28 Jun 2023
Cited by 6 | Viewed by 1323
Abstract
X-ray binary systems (XRBs) exhibit similar dynamics and multimessenger emission mechanisms to active galactic nuclei (AGNs) with the benefit of shorter time scaling. Those systems produce rich spectral energy distributions (SEDs) ranging from the radio band to the very high energy gamma rays. [...] Read more.
X-ray binary systems (XRBs) exhibit similar dynamics and multimessenger emission mechanisms to active galactic nuclei (AGNs) with the benefit of shorter time scaling. Those systems produce rich spectral energy distributions (SEDs) ranging from the radio band to the very high energy gamma rays. The emission origin varies between the system’s accretion disk (X-rays) to the corona and, most notably, to the two twin plasma ejections (jets) that often meet the interstellar medium forming highly observable radio lobes. Modeling of the jets offers an excellent opportunity to understand the intrinsic mechanisms and the jet particles, such as electrons, positrons, and protons. In this work, we employ a lepto-hadronic jet model that assumes particle acceleration through shock waves over separate zonal regions of the jet. The hadronic models consider proton–proton collisions that end up in gamma-ray photons through neutral pion decays. The main leptonic mechanisms involve synchrotron radiation (from both electrons and protons) and inverse Compton scattering of ambient photons (coming from the disk, the corona, and the companion star) on jet electrons. The emissions from the disk, the corona, and the donor star are also included in the SED calculations, along with the photon absorption effects due to their interaction with higher-energy jet photons. We apply the model on a 10M black hole accreting at the Eddington rate out of a 20M companion star. One of our goals is to investigate and determine an optimal frame concerning the values for the free parameters that enter our calculations to produce higher integral fluxes. Full article
(This article belongs to the Section Compact Objects)
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19 pages, 1983 KiB  
Article
A High-Energy and High-Intensity Inverse Compton Scattering Source Based on CompactLight Technology
by Vlad Mușat, Andrea Latina and Gerardo D’Auria
Photonics 2022, 9(5), 308; https://doi.org/10.3390/photonics9050308 - 30 Apr 2022
Cited by 9 | Viewed by 4034
Abstract
An inverse Compton scattering source based on the CompactLight injector and capable of producing MeV gamma-rays with a brilliance several orders of magnitude larger than existing sources is proposed. The CompactLight injector can operate at a bunch repetition rate of 1 kHz, with [...] Read more.
An inverse Compton scattering source based on the CompactLight injector and capable of producing MeV gamma-rays with a brilliance several orders of magnitude larger than existing sources is proposed. The CompactLight injector can operate at a bunch repetition rate of 1 kHz, with trains of 50 bunches and a bunch spacing of 5 ns, giving a maximum total flux of 8.62 × 1011 photons/s. For a normalised emittance of 0.3 mm mrad, an average brilliance of 1.85 × 1014 photons/(smm2mrad2 0.1%BW) could be obtained. A 1 kW colliding laser was considered, corresponding to a laser pulse energy of 50 mJ. Given the electron beam energy up to 300 MeV provided by the CompactLight photoinjector, a maximum photon energy of 2 MeV is obtained. Simulations of inverse Compton scattering were performed using the RF-Track particle tracking software. Parametric scans were used to derive the electron and laser spot sizes maximising the total flux. The accelerator optic components were also determined from the final focus design, which was optimised for a micrometer-level electron beam size at the interaction point. Given a maximum total flux in the order of 1012 photons/s and a maximum output photon energy in the MeV range, the proposed source could be used for various applications, including X-ray imaging. Full article
(This article belongs to the Special Issue Advances and Application of Electron Beam Dynamics)
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17 pages, 6343 KiB  
Article
Long-Term Studies of Cyg X-3 High-Mass X-ray Binary
by Vera G. Sinitsyna and Vera Yu. Sinitsyna
Universe 2022, 8(2), 57; https://doi.org/10.3390/universe8020057 - 18 Jan 2022
Cited by 3 | Viewed by 3044
Abstract
Cyg X-3 is the famous binary system containing a black hole that is actively studied through a wide range of the electromagnetic spectrum, from radio wavelengths to ultra-high-energy gamma-rays, but still not well-understood. The Cyg X-3 focusing investigations obtained from the long-term observations [...] Read more.
Cyg X-3 is the famous binary system containing a black hole that is actively studied through a wide range of the electromagnetic spectrum, from radio wavelengths to ultra-high-energy gamma-rays, but still not well-understood. The Cyg X-3 focusing investigations obtained from the long-term observations at 800 GeV–100 TeV energies with the SHALON telescope are presented. The modulation of the γ-ray emission detected in these studies with an orbital period of 4.8 h was found, proving the identity of the observed object with Cyg X-3. The comparison of light curves in the wide energy range from radio to very high energy γ-rays, folded on the Cyg X-3 orbital period, revealed the differences in the modulation amplitude and phase shifts. The studies of Cyg X-3 activity at very-high energies, including information about TeV and MeV-GeV flare and quenched states and the relationship between the ones in the entire wide energy range, are presented. The modulation of TeV γ-ray flux with orbit along with the high luminosity of the companion star of Cyg X-3 and the close orbit of binary leads to an efficient generation of the part of γ-ray emission in the inverse Compton scattering. The correlation of TeV fluxes with the flaring activity of Cyg X-3 at X-ray and radio ranges could be related to processes of powerful mass ejections from the central regions around the black hole. Full article
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31 pages, 6950 KiB  
Review
Gamma-ray Bursts at the Highest Energies
by Lara Nava
Universe 2021, 7(12), 503; https://doi.org/10.3390/universe7120503 - 17 Dec 2021
Cited by 13 | Viewed by 3008
Abstract
Emission from Gamma-ray bursts is thought to be powered mainly by synchrotron radiation from energetic electrons. The same electrons might scatter these synchrotron seed photons to higher (>10 GeV) energies, building a distinct spectral component (synchrotron self-Compton, SSC). This process is expected to [...] Read more.
Emission from Gamma-ray bursts is thought to be powered mainly by synchrotron radiation from energetic electrons. The same electrons might scatter these synchrotron seed photons to higher (>10 GeV) energies, building a distinct spectral component (synchrotron self-Compton, SSC). This process is expected to take place, but its relevance (e.g., the ratio between the SSC and synchrotron emitted power) is difficult to predict on the basis of current knowledge of physical conditions at GRB emission sites. Very high-energy radiation in GRBs can be produced also by other mechanisms, such as synchrotron itself (if PeV electrons are produced at the source), inverse Compton on external seed photons, and hadronic processes. Recently, after years of efforts, very high-energy radiation has been finally detected from at least four confirmed long GRBs by the Cherenkov telescopes H.E.S.S. and MAGIC. In all four cases, the emission has been recorded during the afterglow phase, well after the end of the prompt emission. In this work, I give an overview, accessible also to non-experts of the field, of the recent detections, theoretical implications, and future challenges, with a special focus on why very high-energy observations are relevant for our understanding of Gamma-ray bursts and which long-standing questions can be finally answered with the help of these observations. Full article
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11 pages, 1039 KiB  
Article
Modelling the Energy Spectra of Radio Relics
by Denis Wittor, Matthias Hoeft and Marcus Brüggen
Galaxies 2021, 9(4), 111; https://doi.org/10.3390/galaxies9040111 - 1 Dec 2021
Cited by 8 | Viewed by 2798
Abstract
Radio relics are diffuse synchrotron sources that illuminate shock waves in the intracluster medium. In recent years, radio telescopes have provided detailed observations about relics. Consequently, cosmological simulations of radio relics need to provide a similar amount of detail. In this methodological work, [...] Read more.
Radio relics are diffuse synchrotron sources that illuminate shock waves in the intracluster medium. In recent years, radio telescopes have provided detailed observations about relics. Consequently, cosmological simulations of radio relics need to provide a similar amount of detail. In this methodological work, we include information on adiabatic compression and expansion, which have been neglected in the past in the modelling of relics. In a cosmological simulation of a merging galaxy cluster, we follow the energy spectra of shock accelerated cosmic-ray electrons using Lagrangian tracer particles. On board of each tracer particle, we compute the temporal evolution of the energy spectrum under the influence of synchrotron radiation, inverse Compton scattering, and adiabatic compression and expansion. Exploratory tests show that the total radio power and, hence, the integrated radio spectrum are not sensitive to the adiabatic processes. This is attributed to small changes in the compression ratio over time. Full article
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8 pages, 364 KiB  
Article
Some Features of the Direct and Inverse Double-Compton Effect as Applied to Astrophysics
by Viktor Dubrovich and Timur Zalialiutdinov
Physics 2021, 3(4), 1167-1174; https://doi.org/10.3390/physics3040074 - 29 Nov 2021
Cited by 2 | Viewed by 2710
Abstract
In the present paper, the process of inverse double-Compton (IDC) scattering is considered in the context of astrophysical applications. It is assumed that the two hard X-ray photons emitted from an astrophysical source are scattered on a free electron and converted into a [...] Read more.
In the present paper, the process of inverse double-Compton (IDC) scattering is considered in the context of astrophysical applications. It is assumed that the two hard X-ray photons emitted from an astrophysical source are scattered on a free electron and converted into a single soft photon of optical range. Using the QED S-matrix formalism for the derivation of a cross-section of direct double-Compton (DDC) scattering and assuming detailed balance conditions, an analytical expression for the cross-section of the IDC process is presented. It is shown that at fixed energies of incident photons, the inverse cross-section has no infrared divergences, and its behavior is completely defined by the spectral characteristics of the photon source itself, in particular by the finite interaction time of radiation with an electron. Thus, even for the direct process, the problem of resolving infrared divergence actually refers to a real physical source of radiation in which photons are never actually plane waves. As a result, the physical frequency profile of the scattered radiation for DDC as well as for IDC processes is a function of both the intensity and line shape of the incident photon field. Full article
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17 pages, 721 KiB  
Review
Relativistic Effects of Rotation in γ-ray Pulsars—Invited Review
by Zaza Osmanov
Galaxies 2021, 9(1), 6; https://doi.org/10.3390/galaxies9010006 - 18 Jan 2021
Cited by 6 | Viewed by 3695
Abstract
In this paper, we consider the relativistic effects of rotation in the magnetospheres of γ-ray pulsars. The paper reviews the progress achieved in this field during the last three decades. For this purpose, we examine the direct centrifugal acceleration of particles and [...] Read more.
In this paper, we consider the relativistic effects of rotation in the magnetospheres of γ-ray pulsars. The paper reviews the progress achieved in this field during the last three decades. For this purpose, we examine the direct centrifugal acceleration of particles and the corresponding limiting factors: the constraints due to the curvature radiation and the inverse Compton scattering of electrons against soft photons. Based on the obtained results, the generation of parametrically excited Langmuir waves and the corresponding Landau–Langmuir centrifugal drive are studied. Full article
(This article belongs to the Special Issue Observations of Gamma-Ray Pulsars)
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