A5004676445- Astrophysics and Cosmic Phenomena
- Dark Matter and Cosmic Phenomena
- Cosmology and Gravitation Theories
- Particle physics theoretical and experimental studies
- Radio Astronomy Observations and Technology
- Neutrino Physics Research
- Black Holes and Theoretical Physics
- Pulsars and Gravitational Waves Research
- High-Energy Particle Collisions Research
- Galaxies: Formation, Evolution, Phenomena
- Quantum Chromodynamics and Particle Interactions
- Gamma-ray bursts and supernovae
- Solar and Space Plasma Dynamics
- Atomic and Subatomic Physics Research
- Lightning and Electromagnetic Phenomena
- Particle Detector Development and Performance
- Particle Accelerators and Free-Electron Lasers
- Ionosphere and magnetosphere dynamics
- Noncommutative and Quantum Gravity Theories
- Geophysics and Gravity Measurements
- Astrophysical Phenomena and Observations
- Relativity and Gravitational Theory
- Computational Physics and Python Applications
- Particle accelerators and beam dynamics
- Geomagnetism and Paleomagnetism Studies
Université Libre de Bruxelles
2015-2024
Institute for Nuclear Research
2014-2024
University of Buenos Aires
2021-2023
Consejo Nacional de Investigaciones Científicas y Técnicas
2021-2023
Instituto de Tecnologías en Detección y Astropartículas
2023
National Technological University
2023
Pierre Auger Observatory
2021-2023
Universidad Nacional de La Plata
2021-2023
Institute of Astronomy and Space Physics
2021-2023
University of the Basque Country
2022
We review some theoretical and phenomenological aspects of massive gravities in 4 dimensions. start from the Fierz--Pauli theory with Lorentz-invariant mass terms then proceed to Lorentz-violating masses. Unlike former theory, models Lorentz-violation have no pathologies spectrum flat nearly backgrounds lead interesting phenomenology.
We made use of the two latest sets Rotational Measures (RMs) extra-galactic radio sources, namely NRAO VLA Sky Survey otation Catalogue, and a compilation by Kronberg&Newton-McGee(2011), to infer global structure Galactic Magnetic Field (GMF). have checked that these data are consistent with each other. Motivated clear patterns in observed distribution RMs over sky, we considered GMF models consisting components: disk (spiral or ring) halo. The parameters components were determined fitting...
We investigate constraints on primordial black holes (PBHs) as dark matter candidates that arise from their capture by neutron stars (NSs). If a PBH is captured NS, the star accreted onto and gets destroyed in very short time. Thus, mere observations of NSs put limits abundance PBHs. High DM densities low velocities are required to constrain fraction PBHs DM. Such conditions may be realized cores globular clusters if latter origin. Assuming possess exceeding several hundred...
Because of their strong gravitational field, neutron stars capture weakly interacting dark matter particles (WIMPs) more efficiently compared to other stars, including the white dwarfs. Once captured, WIMPs sink star center and annihilate, heating star. We find that this heat could lead detectable effects on surface temperature old especially those in dark-matter-rich regions such as Galactic or cores globular clusters. The annihilation is fully efficient even for WIMP-to-nucleon cross...
We put constraints on asymmetric dark matter candidates with spin-dependent interactions based the simple existence of white dwarfs and neutron stars in globular clusters. For a wide range parameters (WIMP mass WIMP-nucleon cross section), weakly interacting massive particles (WIMPs) can be trapped progenitors large numbers once original star collapses to dwarf or star, these WIMPs might self-gravitate eventually collapse forming mini--black hole that destroys star. impose competitive direct...
We argue that current neutron star observations exclude asymmetric bosonic noninteracting dark matter in the range from 2 keV to 16 GeV, including 5--15 GeV favored by DAMA and CoGeNT. If weakly interacting massive particles (WIMPs) are composite of fermions, same limits apply provided compositeness scale is higher than $\ensuremath{\sim}{10}^{12}\text{ }\text{ }\mathrm{GeV}$ (for WIMP mass $\ensuremath{\sim}1\text{ }\mathrm{GeV}$). In case repulsive self-interactions, we large masses...
Cosmic rays are energetic charged particles from extraterrestrial sources, with the highest-energy events thought to come extragalactic sources. Their arrival is infrequent, so detection requires instruments large collecting areas. In this work, we report of an extremely particle recorded by surface detector array Telescope Array experiment. We calculate particle's energy as [Formula: see text] (~40 joules). Its direction points back a void in large-scale structure Universe. Possible...
We construct a consistent model of gravity where the tensor graviton mode is massive, while linearized equations for scalar and vector metric perturbations are not modified. The Friedmann equation acquires an extra dark-energy component leading to accelerated expansion. mass can be as large approximately (10(15) cm)(-1), being constrained by pulsar timing measurements. argue that nonrelativistic gravitational waves comprise cold dark matter may detected future wave searches.
By considering adiabatic contraction of the dark matter (DM) during star formation, we estimate amount DM trapped in stars at their birth. If consists partly primordial black holes (PBHs), they will be together with rest and finally inherited by a compact remnant --- white dwarf (WD) or neutron (NS), which destroy short time. Observations WDs NSs thus impose constraints on abundance PBH. We show that best come from globular clusters exclude consisting entirely PBH mass range $10^{16}{\rm g}...
In some axion dark matter models a dominant fraction of axions resides in dense small-scale substructures, miniclusters. A these substructures is disrupted and forms tidal streams where the density may still be an order magnitude larger than average. We discuss implications for direct searches. estimate miniclusters parameters resulting streams, find that stream-crossing events would occur at rate about $1/(20 {\rm yr})$ 2-3 days, during which signal detectors amplified by factor $\sim 10$....
We propose a mechanism that can convert sizeable fraction of neutron stars into black holes with mass $\sim 1M_\odot$, too light to be produced via standard stellar evolution. show asymmetric fermionic dark matter $\sim$ TeV, attractive self-interaction within the range alleviates problems collisionless cold matter, accumulate in star and collapse, forming seed hole converts rest solar hole. estimate become without contradicting existing observations. Like stars, such could binary systems,...
Mini-black holes made of dark matter that can potentially form in the interior neutron stars always have been thought to grow by accreting core star via a spherical Bondi accretion. However, sometimes significant angular velocities principle stall accretion and change conclusions derived about time it takes for black destroy star. We study effect rotation on growth such evolution hole spin. Assuming no mechanisms momentum evacuation, we find even moderate rates fact at early stages growth....
The authors study a novel stellar catastrophic process where neutron stars swallow primordial black holes, which in turn start swallowing their material, thereby turning them into holes. In particular, they revisit well-known results on dynamical friction by focussing several star models and show that while it is very important during the capture process, accretion dominant post-capture.
We propose a way to constrain the primordial black hole (PBH) abundance in range of PBH masses $m$ around $10^{20}$g based on their capture by Sun-like stars dwarf galaxies, with subsequent star destruction. calculate numerically probability at time its formation an environment typical galaxies. Requiring that no more than fraction $\xi$ galaxy is destroyed PBHs translates into upper limit abundance. For parameters Triangulum II and $\xi=0.5$, we find $\sim 35\%$ dark matter can consist mass...
ABSTRACT If primordial black holes (PBHs) constitute the dark matter (DM), stars forming in dark-matter dominated environments with low velocity dispersions, such as ultra-faint dwarf galaxies, may capture a hole at birth. The probability is non-negligible for PBHs of masses around 1020 g, and increases stellar mass. Moreover, infected are turned into virtually invisible on cosmologically short time-scales. Hence, number observed massive main-sequence dwarfs should be suppressed if DM was...
Black holes with masses $\ensuremath{\approx}1\text{ }\text{ }{M}_{\ensuremath{\bigodot}}$ cannot be produced via stellar evolution. A popular scenario of their formation involves transmutation neutron stars---by accumulation dark matter triggering gravitational collapse in the star centers. We show that this can realized models bosonic despite apparently contradicting requirements on interactions particles: one hand, they should couple to neutrons strongly enough captured inside stars, and...
We analyze the gamma-ray halo around stacked AGNs reported in Ap.J.Lett., 2010, 722, L39. First, we show that angular distribution of gamma-rays is consistent with Crab pulsar, which a point source for Fermi/LAT. This makes it unlikely caused by an electromagnetic cascade TeV photons intergalactic space. then compare point-spread function (PSF) Fermi/LAT and confirm existence excess above PSF. However, demonstrate magnitude size this effect different converted front back parts instrument,...