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Hosking DN, Schekochihin AA. Cosmic-void observations reconciled with primordial magnetogenesis. Nat Commun 2023; 14:7523. [PMID: 37980408 PMCID: PMC10657398 DOI: 10.1038/s41467-023-43258-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 11/03/2023] [Indexed: 11/20/2023] Open
Abstract
It has been suggested that the weak magnetic field hosted by the intergalactic medium in cosmic voids could be a relic from the early Universe. However, accepted models of turbulent magnetohydrodynamic decay predict that the present-day strength of fields originally generated at the electroweak phase transition (EWPT) without parity violation would be too low to explain the observed scattering of γ-rays from TeV blazars. Here, we propose that the decay is mediated by magnetic reconnection and conserves the mean square fluctuation level of magnetic helicity. We find that the relic fields would be stronger by several orders of magnitude under this theory than was indicated by previous treatments, which restores the consistency of the EWPT-relic hypothesis with the observational constraints. Moreover, efficient EWPT magnetogenesis would produce relics at the strength required to resolve the Hubble tension via magnetic effects at recombination and seed galaxy-cluster fields close to their present-day strength.
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Affiliation(s)
- David N Hosking
- Oxford Astrophysics, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH, UK.
- Princeton Center for Theoretical Science, Princeton University, Princeton, NJ, 08544, USA.
- Merton College, Merton Street, Oxford, OX1 4JD, UK.
- Gonville & Caius College, Trinity Street, Cambridge, CB2 1TA, UK.
| | - Alexander A Schekochihin
- Merton College, Merton Street, Oxford, OX1 4JD, UK
- The Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK
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2
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Kahniashvili T, Clarke E, Stepp J, Brandenburg A. Big Bang Nucleosynthesis Limits and Relic Gravitational-Wave Detection Prospects. PHYSICAL REVIEW LETTERS 2022; 128:221301. [PMID: 35714231 DOI: 10.1103/physrevlett.128.221301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/13/2022] [Accepted: 04/21/2022] [Indexed: 06/15/2023]
Abstract
We revisit the big bang nucleosynthesis limits on primordial magnetic fields and/or turbulent motions accounting for the decaying nature of turbulent sources between the time of generation and big bang nucleosynthesis. This leads to larger estimates for the gravitational wave signal than previously expected. We address the detection prospects through space-based interferometers and pulsar timing arrays or astrometric missions for gravitational waves generated around the electroweak and quantum chromodynamics energy scale, respectively.
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Affiliation(s)
- Tina Kahniashvili
- McWilliams Center for Cosmology and Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
- School of Natural Sciences and Medicine, Ilia State University, 0194 Tbilisi, Georgia
- Abastumani Astrophysical Observatory, Tbilisi GE-0179, Georgia
| | - Emma Clarke
- McWilliams Center for Cosmology and Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Jonathan Stepp
- McWilliams Center for Cosmology and Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Axel Brandenburg
- McWilliams Center for Cosmology and Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
- School of Natural Sciences and Medicine, Ilia State University, 0194 Tbilisi, Georgia
- Nordita, KTH Royal Institute of Technology and Stockholm University, 10691 Stockholm, Sweden
- The Oskar Klein Centre, Department of Astronomy, Stockholm University, AlbaNova, SE-10691 Stockholm, Sweden
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3
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Gamma-Ray Bursts at TeV Energies: Theoretical Considerations. GALAXIES 2022. [DOI: 10.3390/galaxies10030074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Gamma-ray bursts (GRBs) are the most luminous explosions in the Universe and are powered by ultra-relativistic jets. Their prompt γ-ray emission briefly outshines the rest of the γ-ray sky, making them detectable from cosmological distances. A burst is followed by, and sometimes partially overlaps with, a similarly energetic but very broadband and longer-lasting afterglow emission. While most GRBs are detected below a few MeV, over 100 have been detected at high (≳0.1 GeV) energies, and several have now been observed up to tens of GeV with the Fermi Large Area Telescope (LAT). A new electromagnetic window in the very-high-energy (VHE) domain (≳0.1 TeV) was recently opened with the detection of an afterglow emission in the (0.1–1)TeV energy band by ground-based imaging atmospheric Cherenkov telescopes. The emission mechanism for the VHE spectral component is not fully understood, and its detection offers important constraints for GRB physics. This review provides a brief overview of the different leptonic and hadronic mechanisms capable of producing a VHE emission in GRBs. The same mechanisms possibly give rise to the high-energy spectral component seen during the prompt emission of many Fermi-LAT GRBs. Possible origins of its delayed onset and long duration well into the afterglow phase, with implications for the emission region and relativistic collisionless shock physics, are discussed. Key results for using GRBs as ideal probes for constraining models of extra-galactic background light and intergalactic magnetic fields, as well as for testing Lorentz invariance violation, are presented.
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Coronado-Blázquez J, Sánchez-Conde MA, Pérez-Romero J, Aguirre-Santaella A. Spatial extension of dark subhalos as seen by
Fermi
-LAT and the implications for WIMP constraints. Int J Clin Exp Med 2022. [DOI: 10.1103/physrevd.105.083006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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5
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Abstract
The propagation of gamma-rays over cosmological distances is the subject of extensive theoretical and observational research at GeV and TeV energies. The mean free path of gamma-rays in the cosmic web is limited above 100 GeV due to the production of electrons and positrons on the cosmic optical and infrared backgrounds. Electrons and positrons cool in the intergalactic medium while gyrating in its magnetic fields, which could cause either its global heating or the production of lower-energy secondary gamma-rays. The energy distribution of gamma-rays surviving the cosmological journey carries observed absorption features that gauge the emissivity of baryonic matter over cosmic time, constrain the distance scale of ΛCDM cosmology, and limit the alterations of the interaction cross section. Competitive constraints are, in particular, placed on the cosmic star-formation history as well as on phenomena expected from quantum gravity and string theory, such as the coupling to hypothetical axion-like particles or the violation of Lorentz invariance. Recent theoretical and observational advances offer a glimpse of the multi-wavelength and multi-messenger path that the new generation of gamma-ray observatories is about to open.
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6
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Abstract
High energy photons from astrophysical sources are unique probes for some predictions of candidate theories of Quantum Gravity (QG). In particular, Imaging atmospheric Cherenkov telescope (IACTs) are instruments optimised for astronomical observations in the energy range spanning from a few tens of GeV to ∼100 TeV, which makes them excellent instruments to search for effects of QG. In this article, we will review QG effects which can be tested with IACTs, most notably the Lorentz invariance violation (LIV) and its consequences. It is often represented and modelled with photon dispersion relation modified by introducing energy-dependent terms. We will describe the analysis methods employed in the different studies, allowing for careful discussion and comparison of the results obtained with IACTs for more than two decades. Loosely following historical development of the field, we will observe how the analysis methods were refined and improved over time, and analyse why some studies were more sensitive than others. Finally, we will discuss the future of the field, presenting ideas for improving the analysis sensitivity and directions in which the research could develop.
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Abstract
One of the most promising ways to probe intergalactic magnetic fields (IGMFs) is through gamma rays produced in electromagnetic cascades initiated by high-energy gamma rays or cosmic rays in the intergalactic space. Because the charged component of the cascade is sensitive to magnetic fields, gamma-ray observations of distant objects such as blazars can be used to constrain IGMF properties. Ground-based and space-borne gamma-ray telescopes deliver spectral, temporal, and angular information of high-energy gamma-ray sources, which carries imprints of the intervening magnetic fields. This provides insights into the nature of the processes that led to the creation of the first magnetic fields and into the phenomena that impacted their evolution. Here we provide a detailed description of how gamma-ray observations can be used to probe cosmic magnetism. We review the current status of this topic and discuss the prospects for measuring IGMFs with the next generation of gamma-ray observatories.
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Di Y, Wang J, Zhou R, Bian L, Cai RG, Liu J. Magnetic Field and Gravitational Waves from the First-Order Phase Transition. PHYSICAL REVIEW LETTERS 2021; 126:251102. [PMID: 34241495 DOI: 10.1103/physrevlett.126.251102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 05/27/2021] [Indexed: 06/13/2023]
Abstract
We perform the three-dimensional lattice simulation of the magnetic field and gravitational wave productions from bubble collisions during the first-order electroweak phase transition. Except for the gravitational wave, the power-law spectrum of the magnetic field strength is numerically calculated for the first time, which is of a broken power-law spectrum: B_{ξ}∝f^{0.91} for the low-frequency region of f<f_{⋆} and B_{ξ}∝f^{-1.65} for the high-frequency region of f>f_{⋆} in the thin-wall limit, with the peak frequency being f_{⋆}∼5 Hz at the phase transition temperature 100 GeV. When the hydrodynamics is taken into account, the generated magnetic field strength can reach B_{ξ}∼10^{-7} G at a correlation length ξ∼10^{-7} pc, which may seed the large scale magnetic fields. Our study shows that the measurements of cosmic magnetic field strength and gravitational waves are complementary to probe new physics admitting electroweak phase transition.
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Affiliation(s)
- Yuefeng Di
- Department of Physics, Chongqing University, Chongqing 401331, China
| | - Jialong Wang
- Department of Physics, Chongqing University, Chongqing 401331, China
| | - Ruiyu Zhou
- Department of Physics, Chongqing University, Chongqing 401331, China
| | - Ligong Bian
- Department of Physics, Chongqing University, Chongqing 401331, China
| | - Rong-Gen Cai
- CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100190, China, School of Physical Sciences, University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China, and School of Fundamental Physics and Mathematical Sciences, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
| | - Jing Liu
- School of Fundamental Physics and Mathematical Sciences, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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Vachaspati T. Progress on cosmological magnetic fields. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2021; 84:074901. [PMID: 34015776 DOI: 10.1088/1361-6633/ac03a9] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 05/20/2021] [Indexed: 06/12/2023]
Abstract
A variety of observations impose upper limits at the nano Gauss level on magnetic fields that are coherent on inter-galactic scales while blazar observations indicate a lower bound ∼10-16G. Such magnetic fields can play an important astrophysical role, for example at cosmic recombination and during structure formation, and also provide crucial information for particle physics in the early Universe. Magnetic fields with significant energy density could have been produced at the electroweak phase transition. The evolution and survival of magnetic fields produced on sub-horizon scales in the early Universe, however, depends on the magnetic helicity which is related to violation of symmetries in fundamental particle interactions. The generation of magnetic helicity requires new CP violating interactions that can be tested by accelerator experiments via decay channels of the Higgs particle.
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Affiliation(s)
- Tanmay Vachaspati
- Physics Department, Arizona State University, Tempe, AZ 85287, United States of America
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Baym G, Peng JC. Evolution of Primordial Neutrino Helicities in Astrophysical Magnetic Fields and Implications for Their Detection. PHYSICAL REVIEW LETTERS 2021; 126:191803. [PMID: 34047568 DOI: 10.1103/physrevlett.126.191803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 04/13/2021] [Accepted: 04/16/2021] [Indexed: 06/12/2023]
Abstract
Since decoupling in the early Universe in helicity states, primordial neutrinos propagating in astrophysical magnetic fields precess and undergo helicity changes. In view of various experimental bounds allowing a large magnetic moment of neutrinos, we estimate the helicity flipping for relic neutrinos in both cosmic and galactic magnetic fields. The flipping probability is sensitive both to the neutrino magnetic moment and the structure of the magnetic fields and is a potential probe of the fields. As we find, even a magnetic moment well below that suggested by XENON1T could significantly affect relic neutrino helicities and their detection rate via inverse tritium beta decay.
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Affiliation(s)
- Gordon Baym
- Illinois Center for Advanced Studies of the Universe and Department of Physics, University of Illinois, 1110 West Green Street, Urbana, Illinois 61801, USA
| | - Jen-Chieh Peng
- Illinois Center for Advanced Studies of the Universe and Department of Physics, University of Illinois, 1110 West Green Street, Urbana, Illinois 61801, USA
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Abstract
Continuum gamma-ray emission produced by interactions of cosmic rays with interstellar matter and radiation fields is a probe of non-thermal particle populations in galaxies. After decades of continuous improvements in experimental techniques and an ever-increasing sky and energy coverage, gamma-ray observations reveal in unprecedented detail the properties of galactic cosmic rays. A variety of scales and environments are now accessible to us, from the local interstellar medium near the Sun and the vicinity of cosmic-ray accelerators, out to the Milky Way at large and beyond, with a growing number of gamma-ray emitting star-forming galaxies. Gamma-ray observations have been pushing forward our understanding of the life cycle of cosmic rays in galaxies and, combined with advances in related domains, they have been challenging standard assumptions in the field and have spurred new developments in modelling approaches and data analysis methods. We provide a review of the status of the subject and discuss perspectives on future progress.
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Achikanath Chirakkara R, Federrath C, Trivedi P, Banerjee R. Efficient Highly Subsonic Turbulent Dynamo and Growth of Primordial Magnetic Fields. PHYSICAL REVIEW LETTERS 2021; 126:091103. [PMID: 33750146 DOI: 10.1103/physrevlett.126.091103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 12/11/2020] [Accepted: 01/14/2021] [Indexed: 06/12/2023]
Abstract
We present the first study on the amplification of magnetic fields by the turbulent dynamo in the highly subsonic regime, with Mach numbers ranging from 10^{-3} to 0.4. We find that for the lower Mach numbers the saturation efficiency of the dynamo (E_{mag}/E_{kin})_{sat} increases as the Mach number decreases. Even in the case when injection of energy is purely through longitudinal forcing modes, (E_{mag}/E_{kin})_{sat}≳10^{-2} at a Mach number of 10^{-3}. We apply our results to magnetic field amplification in the early Universe and predict that a turbulent dynamo can amplify primordial magnetic fields to ≳10^{-16} G on scales up to 0.1 pc and ≳10^{-13} G on scales up to 100 pc. This produces fields compatible with lower limits of the intergalactic magnetic field inferred from blazar γ-ray observations.
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Affiliation(s)
- Radhika Achikanath Chirakkara
- Department of Physics, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pune 411008, India
- Research School of Astronomy and Astrophysics, Australian National University, Canberra, Australian Capital Territory 2611, Australia
- Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany
| | - Christoph Federrath
- Research School of Astronomy and Astrophysics, Australian National University, Canberra, Australian Capital Territory 2611, Australia
| | - Pranjal Trivedi
- Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany
- Universität Hamburg, II. Institut für Theoretische Physik, Luruper Chaussee 149, 22761 Hamburg, Germany
- Department of Physics, Sri Venkateswara College, University of Delhi, New Delhi 110020, India
| | - Robi Banerjee
- Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany
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14
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Fujita T, Kamada K, Nakai Y. Gravitational waves from primordial magnetic fields via photon-graviton conversion. Int J Clin Exp Med 2020. [DOI: 10.1103/physrevd.102.103501] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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15
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Abstract
Supermassive black holes lying in the center of galaxies can launch relativistic jets of plasma along their polar axis. The physics of black-hole jets is a very active research topic in astrophysics, owing to the fact that many questions remain open on the physical mechanisms of jet launching, of particle acceleration in the jet, and on the radiative processes. In this work I focus on the last item, and present a review of the current understanding of radiative emission processes in supermassive-black-hole jets.
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Wang ZR, Xi SQ, Liu RY, Xue R, Wang XY. Constraints on the intergalactic magnetic field from
γ
-ray observations of GRB 190114C. Int J Clin Exp Med 2020. [DOI: 10.1103/physrevd.101.083004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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18
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γ-ray and ν Searches for Dark-Matter Subhalos in the Milky Way with a Baryonic Potential. GALAXIES 2019. [DOI: 10.3390/galaxies7020060] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The distribution of dark-matter (DM) subhalos in our galaxy remains disputed, leading to varying γ -ray and ν flux predictions from their annihilation or decay. In this work, we study how, in the inner galaxy, subhalo tidal disruption from the galactic baryonic potential impacts these signals. Based on state-of-the art modeling of this effect from numerical simulations and semi-analytical results, updated subhalo spatial distributions are derived and included in the CLUMPY code. The latter is used to produce a thousand realizations of the γ -ray and ν sky. Compared to predictions based on DM only, we conclude a decrease of the flux of the brightest subhalo by a factor of 2 to 7 for annihilating DM and no impact on decaying DM: the discovery prospects or limits subhalos can set on DM candidates are affected by the same factor. This study also provides probability density functions for the distance, mass, and angular distribution of the brightest subhalo, among which the mass may hint at its nature: it is most likely a dwarf spheroidal galaxy in the case of strong tidal effects from the baryonic potential, whereas it is lighter and possibly a dark halo for DM only or less pronounced tidal effects.
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Abstract
Increasing evidence suggests that cosmological sheets, filaments, and voids may be substantially magnetized today. The origin of magnetic fields in the intergalactic medium (IGM) is, however, currently uncertain. It seems well known that non-standard extensions to the physics of the standard model can provide mechanisms susceptible of magnetizing the universe at large. Perhaps less well known is the fact that standard, classical physics of matter–radiation interactions actually possesses the same potential. We discuss a magnetogenesis mechanism based on the exchange of momentum between hard photons and electrons in an inhomogeneous IGM. Operating in the neighborhood of ionizing sources during the epoch of reionization, this mechanism is capable of generating magnetic seeds of relevant strengths over scales comparable to the distance between ionizing sources. In addition, summing up the contributions of all ionizing sources and taking into account the distribution of gas inhomogeneities, we show that this mechanism leaves the IGM, at the end of reionization, with a level of magnetization that might account, when amplification mechanisms take over, for the magnetic fields strengths in the current cosmic web.
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