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Related papers: Structure Formation and Microlensing with Axion Mi…

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We identify axion miniclusters collapsing in the radiation-dominated era and follow them to redshift $z=99$ with N-body simulations. We find that the majority of the densest miniclusters end up in the center of larger minicluster halos at…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-29 Benedikt Eggemeier , Ananthu Krishnan Anilkumar , Klaus Dolag

Non-linear effects in the evolution of the axion field in the early Universe may lead to the formation of gravitationally bound clumps of axions, known as ``miniclusters.'' Minicluster masses and radii should be in the range $M_{\rm…

Astrophysics · Physics 2009-10-28 E. W. Kolb , I. I. Tkachev

The phase transition responsible for axion dark matter production can create large amplitude isocurvature perturbations which collapse into dense objects known as axion miniclusters. We use microlensing data from the EROS survey, and from…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-19 Malcolm Fairbairn , David J. E. Marsh , Jérémie Quevillon

If dark matter is an axion-like-particle a significant fraction of the present day relic abundance could be concentrated in compact gravitationally bound miniclusters. We study the minicluster masses compatible with the dark matter relic…

High Energy Physics - Phenomenology · Physics 2017-03-08 Edward Hardy

We study the gravitational collapse of axion dark matter fluctuations in the post-inflationary scenario, so-called axion miniclusters, with N-body simulations. Largely confirming theoretical expectations, overdensities begin to collapse in…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-22 Benedikt Eggemeier , Javier Redondo , Klaus Dolag , Jens C. Niemeyer , Alejandro Vaquero

If the symmetry breaking leading to the origin of the axion dark matter field occurs after the end of inflation and is never restored, then overdensities in the axion field collapse to form dense objects known in the literature as axion…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-14 Luca Visinelli , Javier Redondo

The Peak-Patch algorithm is used to identify the densest minicluster seeds in the initial axion density field simulated from string decay. The fate of these dense seeds is found by tracking the subsequent gravitational collapse in…

High Energy Physics - Phenomenology · Physics 2022-11-30 David Ellis , David J. E. Marsh , Benedikt Eggemeier , Jens Niemeyer , Javier Redondo , Klaus Dolag

Dark matter in the form of axions is expected to form miniclusters, and their dense regions can harbor compact axion stars. Such axion stars could be discovered by microlensing events. In particular, some candidate events reported by Subaru…

High Energy Physics - Phenomenology · Physics 2023-04-10 Sunao Sugiyama , Masahiro Takada , Alexander Kusenko

Axionic dark matter can form miniclusters and minicluster halos from inhomogenuities in the early Universe. If MCHs are sufficiently massive, their existence can be revealed by small-scale gravitational tidal perturbation to halo-like…

High Energy Physics - Phenomenology · Physics 2024-09-05 Zihang Wang , Yu Gao

Axion-like dark matter whose symmetry breaking occurs after the end of inflation predicts enhanced primordial density fluctuations at small scales. This leads to dense axion minihalos (or miniclusters) forming early in the history of the…

High Energy Physics - Phenomenology · Physics 2023-11-28 Patrick J. Fox , Neal Weiner , Huangyu Xiao

A consequence of QCD axion dark matter being born after inflation is the emergence of small-scale substructures known as miniclusters. Although miniclusters merge to form minihalos, this intrinsic granularity is expected to remain imprinted…

High Energy Physics - Phenomenology · Physics 2024-08-23 Ciaran A. J. O'Hare , Giovanni Pierobon , Javier Redondo

Non-linear effects in the evolution of the axion field in the early Universe may lead to the formation of gravitationally bound clumps of axions, known as "miniclusters". Minicluster masses should be in the range $M_{\rm mc}\sim10^{-12}…

High Energy Astrophysical Phenomena · Physics 2015-06-23 Igor I. Tkachev

When Peccei-Quinn (PQ) symmetry breaking happens after inflation, the axion field takes random values in causally disconnected regions. This leads to fluctuations of order one in the axion energy density around the QCD epoch. These…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-09 Jonas Enander , Andreas Pargner , Thomas Schwetz

Axions are a viable candidate for Cold Dark Matter (CDM) which should generically form minihalos of sub-planetary masses from white-noise isocurvature density fluctuations if the Peccei-Quinn phase transition occurs after inflation. Despite…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-22 Liang Dai , Jordi Miralda-Escudé

We model the formation, evolution and astrophysical effects of dark compact Scalar Miniclusters (``ScaMs''). These objects arise when a scalar field, with an axion-like or Higgs-like potential, undergoes a second order phase transition…

Astrophysics · Physics 2008-11-26 Kathryn M. Zurek , Craig J. Hogan , Thomas R. Quinn

We study the small scale structure of axion dark matter in the post-inflationary scenario, which predicts the formation of low-mass, high-density clumps of gravitationally bound axions called axion miniclusters. To this end, we follow…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-11 Alejandro Vaquero , Javier Redondo , Julia Stadler

A fraction of light scalar dark matter, especially axions, may organize into Bose-Einstein condensates, gravitationally bound clumps, "boson stars", and be present in large number in galactic halos today. We compute the expected number of…

High Energy Physics - Phenomenology · Physics 2022-06-22 Kohei Fujikura , Mark P. Hertzberg , Enrico D. Schiappacasse , Masahide Yamaguchi

We present novel findings concerning the parameter space of axion stars, extended object forming in dense dark matter environments through gravitational condensation. We emphasize their formation within the dense minihalos that potentially…

High Energy Physics - Phenomenology · Physics 2024-10-04 Ziwen Yin , Luca Visinelli

We use a modified version of the Peak Patch excursion set formalism to compute the mass and size distribution of QCD axion miniclusters from a fully non-Gaussian initial density field obtained from numerical simulations of axion string…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-12 David Ellis , David J. E. Marsh , Christoph Behrens

Axions are some of the best motivated particles beyond the Standard Model. We show how the attractive self-interactions of dark matter (DM) axions over a broad range of masses, from $10^{-22}$ eV to $10^7$ GeV, can lead to nongravitational…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-15 Asimina Arvanitaki , Savas Dimopoulos , Marios Galanis , Luis Lehner , Jedidiah O. Thompson , Ken Van Tilburg
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