A5001839515- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Radio Astronomy Observations and Technology
- Astrophysics and Star Formation Studies
- Dark Matter and Cosmic Phenomena
- Solar and Space Plasma Dynamics
- Neutrino Physics Research
- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Particle Accelerators and Free-Electron Lasers
- Particle Detector Development and Performance
- Pulsars and Gravitational Waves Research
- Astronomical Observations and Instrumentation
- Ionosphere and magnetosphere dynamics
- Cosmology and Gravitation Theories
- Astronomy and Astrophysical Research
- Laser-Plasma Interactions and Diagnostics
- Nuclear Physics and Applications
- Superconducting Materials and Applications
- Radiation Detection and Scintillator Technologies
- Magnetic confinement fusion research
- Scientific Research and Discoveries
- Superconducting and THz Device Technology
Laboratoire Univers et Particules de Montpellier
2017-2024
Institut National de Physique Nucléaire et de Physique des Particules
2021-2024
Université de Montpellier
2017-2024
Centre National de la Recherche Scientifique
2017-2024
Extreme Light Infrastructure Beamlines
2019-2024
Czech Academy of Sciences, Astronomical Institute
2017-2023
Czech Academy of Sciences, Institute of Physics
2019-2023
Palacký University Olomouc
2023
National Academy of Sciences of Ukraine
2023
Institute of Nuclear Physics, Polish Academy of Sciences
2023
We provide an updated assessment of the power Cherenkov Telescope Array (CTA) to search for thermally produced dark matter at TeV scale, via associated gamma-ray signal from pair-annihilating particles in region around Galactic centre. find that CTA will open a new window discovery potential, significantly extending range robustly testable models given standard cuspy profile density distribution. Importantly, even cored profile, projected sensitivity be sufficient probe various...
Abstract The SST-1M (webpage: https://sst-1m.space ) is a Small-Sized Telescope (SST) designed to provide cost-effective and high-performance solution for gamma-ray astrophysics, particularly energies beyond few TeV. goal integrate this telescope into an array of similar instruments, leveraging its lightweight design, earthquake resistance, established Davies-Cotton configuration. Additionally, optical system function without protective dome, allowing it withstand the harsh atmospheric...
The origin of ultra-high energy cosmic rays (UHECRs) has been an open question for decades. Here, we use a combination hydrodynamic simulations and general physical arguments to demonstrate that UHECRs can in principle be produced by diffusive shock acceleration (DSA) shocks the backflowing material radio galaxy lobes. These occur after jet passed through relativistic termination shock. Recently, several authors have demonstrated highly are not effective accelerating UHECRs. our proposed...
<i>Context. <i/>The environs of massive, early-type stars have been inspected in recent years the search for sites where particles can be accelerated up to relativistic energies. Wind regions massive binaries that collide already established as sources high-energy emission; however, there is a different scenario strong shocks also produced: bow-shaped region matter piled by action stellar wind runaway star interacting with interstellar medium.<i>Aims. <i/>We study bow-shock produced very...
Dense populations of stars surround the nuclear regions galaxies. In active galactic nuclei, these can interact with relativistic jets launched by supermasive black hole. this work, we study interaction early-type in nuclei. A bow-shaped double-shock structure is formed as a consequence jet and stellar wind each star. Particles be accelerated up to energies shocks emit high-energy radiation. We compute, considering different densities core, gamma-ray emission produced non-thermal radiative...
Radio emission from protostellar jets is usually dominated by free-free thermal electrons. However, in some cases, it has been proposed that non-thermal could also be present. This additional contribution inferred through negative spectral indices at centimeter wavelengths regions of the radio jets. In case HH 80-81, one most powerful known, linearly polarized detected, revealing synchrotron nature a population relativistic particles jet. result implies an acceleration mechanism should...
The origin of ultra-high energy cosmic rays (UHECRs) is still unknown. It has recently been proposed that UHECR anisotropies can be attributed to starburst galaxies or active galactic nuclei. We suggest the latter more likely and giant-lobed radio such as Centaurus A Fornax explain data.
Context . The neutrino event IceCube−170922A appears to originate from the BL Lac object TXS 0506+056. To understand creation process and localize emission site, we studied radio images of jet at 15 GHz. Aims Other objects show properties similar those 0506+056, such as multiwavelength variability or a curved jet. However, date only 0506+056 has been identified emitter. aim this paper is determine what makes parsec-scale specific in respect. Methods We reanalyzed remodeled 16 VLBA GHz...
Dense and cold clouds seem to populate the broad line region surrounding central black hole in AGNs. These could interact with AGN jet base this have observational consequences. We want study gamma-ray emission produced by these jet-cloud interactions, explore under which conditions radiation would be detectable. investigate hydrodynamical properties of interactions resulting shocks, develop a model compute spectral energy distribution generated particles accelerated shocks. discuss our...
We examine limits to the energy which cosmic rays can be accelerated by relativistic shocks, showing that acceleration of light ions as high 100 EeV is unlikely. The implication our estimates if ultra-high are then those shocks probably not relativistic.
ABSTRACT While most protostellar jets present free–free emission at radio wavelengths, synchrotron has also been proposed to be in a handful of these objects. The presence nonthermal inferred by negative spectral indices centimeter wavelengths. In one case (the HH 80-81 jet arising from massive protostar), its nature was confirmed the detection linearly polarized emission. One main consequences results is that implies relativistic particles among nonrelativistic material jets. Therefore, an...
Aims.A huge multiwavelength campaign targeting the blazar AO 0235+164 was organized by Whole Earth Blazar Telescope (WEBT) in 2003–2005 to study variability properties of source.
Massive protostars have associated bipolar outflows with velocities of hundreds km s$^{-1}$. Such can produce strong shocks when interact the ambient medium leading to regions non-thermal radio emission. We aim at exploring under which conditions relativistic particles are accelerated terminal protostellar jets and significant gamma-ray estimate necessary for particle acceleration up very high energies production in hot spots massive embedded dense molecular clouds. show that Bremsstrahlung...
<i>Context. <i/>High-mass microquasars are binary systems consisting of a massive star and an accreting compact object from which relativistic jets launched. There is considerable observational evidence that winds stars clumpy. Individual clumps may interact with the in high-mass to produce outbursts high-energy emission. Gamma-ray flares have been detected some X-ray binaries, such as Cygnus X-1, probably LS 5039 I+61 303.<i>Aims. <i/>We predict emission produced by interaction between jet...
Variability amplitudes larger than 1 magnitude over time-scales of a few tens minutes have recently been reported in the optical light-curves several blazars. In order to independently verify real occurrence such extremely violent events, we undertook an observational study selected sample three blazars: PKS 0048-097, 0754+100, and 1510-089. Possible systematic error sources during data acquisition reduction were carefully evaluated. We indeed found flux variability at intra-night all...
Context.Massive stars form in dense and massive molecular cores. The exact formation mechanism is unclear, but it possible that some are formed by processes similar to those produce the low-mass stars, with accretion/ejection phenomena occurring at point of evolution protostar. This picture seems be supported detection a collimated stellar wind emanating from protostar IRAS 16547-4247. A triple radio source associated protostar: compact core two lobes. emission southern lobe clearly...
The radio-knots of the Herbig–Haro (HH) 80/81/80N jet extend from HH 80 object to recently discovered Source 34 and has a total projected size 10.3 pc, constituting largest collimated radio-jet system known so far. It is powered by bright infrared source IRAS 18162−2048 associated with massive young stellar object. We report 6 cm JVLA observations that, compared previous VLA carried out in 1989, allow us derive proper motions 80, 81, 80N radio knots located about 2.5 pc away projection...
The Cherenkov Telescope Array (CTA), the new-generation ground-based observatory for γ astronomy, provides unique capabilities to address significant open questions in astrophysics, cosmology, and fundamental physics. We study some of salient areas cosmology that can be explored as part Key Science Projects CTA, through simulated observations active galactic nuclei (AGN) their relativistic jets. Observations AGN with CTA will enable a measurement absorption on extragalactic background light...
Abstract The spectra of active galactic nuclei exhibit broad-emission lines that presumably originate in the broad-line region (BLR) with gaseous-dusty clouds a predominantly Keplerian motion around central black hole. Signatures both inflow and outflow are frequently seen. dynamical character BLR is consistent scenario has been branded as failed radiatively accelerated dusty outflow. In this scheme, frequent high-velocity impacts falling back onto underlying accretion disk predicted. impact...
In the subclass of high-mass X-ray binaries known as "microquasars," relativistic hadrons in jets launched by compact object can interact with cold protons from star's radiatively driven wind, producing pions that then quickly decay into gamma rays. Since resulting gamma-ray emissivity depends on target density, detection rapid variability microquasars Gamma-Ray Large Area Space Telescope and new generation Cherenkov imaging arrays could be used to probe clumped structure stellar wind. We...
We present multi--epoch VLBA observations of the compact wind collision region in Cyg OB2 #5 system. These observation confirm arc-shaped morphology emission reported earlier. The total flux as a function time is roughly constant when source "on", but falls below detection limit approaches periastron its orbit around contact binary at center In addition, one "on" epochs, drops to about fifth average value. suggest that this apparent variation could result from inhomogeneity hides part rather...
Cosmic ray (CR) currents through magnetised plasma drive strong instabilities producing amplification of the magnetic field. This helps explain CR energy spectrum as well observations supernova remnants and radio galaxy hot spots. Using magnetohydrodynamic (MHD) simulations, we study behaviour non-resonant hybrid (NRH) instability (also known Bell instability) in case perpendicular parallel to initial We demonstrate that extending simulations 3D reveals a different character turbulence from...
Very-high Energy (VHE) gamma-ray astroparticle physics is a relatively young field, and observations over the past decade have surprisingly revealed almost two hundred VHE emitters which appear to act as cosmic particle accelerators. These sources are an important component of Universe, influencing evolution stars galaxies. At same time, they also probe in most extreme environments known - such supernova explosions, around or after merging black holes neutron stars. However, existing...