Journal articles: 'Galactic proton'

1

Sikora, Marek, Bronisław Rudak, and Mitchell Begelman. "Relativistic Neutrons in Active Galactic Nuclei." Symposium - International Astronomical Union 134 (1989): 215–16. http://dx.doi.org/10.1017/s0074180900140902.

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A substantial fraction of the radiation from an active galactic nucleus (AGN) is apparently nonthermal in origin, and is probably produced by ultrarelativistic electrons. How much energy goes into relativistic protons is uncertain, but it is likely to be comparable to the electron energy or larger. Indeed, several authors (Sikora et al. 1987; Kazanas and Ellison 1986; Zdziarski 1986) have shown that proton-photon and proton-proton collisions can be efficient sources of relativistic pairs in the central engine of an AGN. Thus it is not necessary for electrons to be accelerated directly in AGNs, provided that protons are accelerated with high enough efficiency.

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Fiandrini, E., B. Bertucci, N. Tomassetti, and B. Khiali. "New solar modulation modeling of the galactic proton flux measured by the AMS02 and PAMELA experiments." EPJ Web of Conferences 209 (2019): 01032. http://dx.doi.org/10.1051/epjconf/201920901032.

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A thorough understanding of solar effects on the galactic cosmic rays is relevant both to infer the local interstellar spectrum characteristics and to investigate the dynamics of charged particles in the heliosphere. We present a newly developed numerical modulation model to study the transport of galactic protons in the heliosphere. The model was applied to the 27-day averaged galactic proton flux recently released by the PAMELA and AMS02 experiments, covering an extended time period from mid-2006 to mid-2017.

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Jansen, F., K. P. Wenzel, D. O' Sullivan, and A. Thompson. "The Bulge of the Milky Way and cosmic rays." Symposium - International Astronomical Union 153 (1993): 283–84. http://dx.doi.org/10.1017/s0074180900123265.

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The propagation of cosmic ray protons and anti–protons from the inner Galaxy via the galactic halo to the Sun supplies a good agreement with the observed cosmic ray gradient and is in the order of the measured anti-proton flux. Ultra heavy cosmic ray nuclei may have the same origin.

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Buchvarova, M., and P. Velinov. "Cosmic ray spectra in planetary atmospheres." Proceedings of the International Astronomical Union 4, S257 (September 2008): 471–73. http://dx.doi.org/10.1017/s1743921309029718.

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AbstractOur model generalizes the differential D(E) and integral D(>E) spectra of cosmic rays (CR) during the 11-year solar cycle. The empirical model takes into account galactic (GCR) and anomalous cosmic rays (ACR) heliospheric modulation by four coefficients. The calculated integral spectra in the outer planets are on the basis of mean gradients: for GCR – 3%/AU and 7%/AU for anomalous protons. The obtained integral proton spectra are compared with experimental data, the CRÈME96 model for the Earth and theoretical results of 2D stochastic model. The proposed analytical model gives practical possibility for investigation of experimental data from measurements of galactic cosmic rays and their anomalous component.

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Abdollahi, S., F. Acero, M. Ackermann, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, et al. "Search for New Cosmic-Ray Acceleration Sites within the 4FGL Catalog Galactic Plane Sources." Astrophysical Journal 933, no. 2 (July 1, 2022): 204. http://dx.doi.org/10.3847/1538-4357/ac704f.

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Abstract Cosmic rays are mostly composed of protons accelerated to relativistic speeds. When those protons encounter interstellar material, they produce neutral pions, which in turn decay into gamma-rays. This offers a compelling way to identify the acceleration sites of protons. A characteristic hadronic spectrum, with a low-energy break around 200 MeV, was detected in the gamma-ray spectra of four supernova remnants (SNRs), IC 443, W44, W49B, and W51C, with the Fermi Large Area Telescope. This detection provided direct evidence that cosmic-ray protons are (re-)accelerated in SNRs. Here, we present a comprehensive search for low-energy spectral breaks among 311 4FGL catalog sources located within 5° from the Galactic plane. Using 8 yr of data from the Fermi Large Area Telescope between 50 MeV and 1 GeV, we find and present the spectral characteristics of 56 sources with a spectral break confirmed by a thorough study of systematic uncertainty. Our population of sources includes 13 SNRs for which the proton–proton interaction is enhanced by the dense target material; the high-mass gamma-ray binary LS I+61 303; the colliding wind binary η Carinae; and the Cygnus star-forming region. This analysis better constrains the origin of the gamma-ray emission and enlarges our view to potential new cosmic-ray acceleration sites.

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Fang, Jun, Qi Xia, Shiting Tian, Liancheng Zhou, and Huan Yu. "Kinetic simulation of electron, proton and helium acceleration in a non-relativistic quasi-parallel shock." Monthly Notices of the Royal Astronomical Society 512, no. 4 (April 14, 2022): 5418–22. http://dx.doi.org/10.1093/mnras/stac886.

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ABSTRACT In addition to accelerating electrons and protons, non-relativistic quasi-parallel shocks are expected to possess the ability to accelerate heavy ions. The shocks in supernova remnants are generally supposed to be accelerators of Galactic cosmic rays, which consist of many species of particles. We investigate the diffusive shock acceleration of electrons, protons and helium ions in a non-relativistic quasi-parallel shock through a 1D particle-in-cell simulation with a helium-to-proton number density ratio of 0.1, which is relevant for Galactic cosmic rays. The simulation indicates that waves can be excited by the flow of energetic protons and helium ions upstream of a non-relativistic quasi-parallel shock with a sonic Mach number of 14 and an Alfvén Mach number of 19.5 in the shock rest frame, and that the charged particles are scattered by the self-generated waves and accelerated gradually. Moreover, the spectra of the charged particles downstream of the shock are thermal with a non-thermal tail, and the acceleration is efficient, with about $7{{\ \rm per\ cent}}$ and $5.4{{\ \rm per\ cent}}$ of the bulk kinetic energy transferred into the non-thermal protons and helium ions, respectively, in the near downstream region by the end of the simulation.

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7

Casolino, Marco, N. De Simone, and V. Formato. "PAMELA recent results on galactic proton and helium." Nuclear Physics B - Proceedings Supplements 212-213 (March 2011): 362–67. http://dx.doi.org/10.1016/j.nuclphysbps.2011.03.049.

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8

Khokhlov, Dmitri L. "Planck Neutrinos as Ultra High Energy Cosmic Rays." Open Astronomy 29, no. 1 (June 24, 2020): 40–46. http://dx.doi.org/10.1515/astro-2020-0005.

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AbstractThe studied conjecture is that ultra high energy cosmic rays (UHECRs) are hypothetical Planck neutrinos arising in the decay of the protons falling onto the gravastar. The proton is assumed to decay at the Planck scale into positron and four Planck neutrinos. The supermassive black holes inside active galactic nuclei, while interpreted as gravastars, are considered as UHECR sources. The scattering of the Planck neutrinos by the proton at the Planck scale is considered. The Planck neutrinos contribution to the CR events may explain the CR spectrum from 5 × 1018 eV to 1020 eV. The muon number in the Planck neutrinos-initiated shower is estimated to be larger by a factor of 3/2 in comparison with the standard model that is consistent with the observational data.

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Werhahn, Maria, Christoph Pfrommer, Philipp Girichidis, Ewald Puchwein, and Rüdiger Pakmor. "Cosmic rays and non-thermal emission in simulated galaxies − I. Electron and proton spectra compared to Voyager-1 data." Monthly Notices of the Royal Astronomical Society 505, no. 3 (May 10, 2021): 3273–94. http://dx.doi.org/10.1093/mnras/stab1324.

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ABSTRACT Current-day cosmic ray (CR) propagation studies use static Milky Way models and fit parametrized source distributions to data. Instead, we use three-dimensional magnetohydrodynamic (MHD) simulations of isolated galaxies with the moving-mesh code arepo that self-consistently accounts for hydrodynamic effects of CR protons. In post-processing, we calculate their steady-state spectra, taking into account all relevant loss processes. We show that this steady-state assumption is well justified in the disc and generally for regions that emit non-thermal radio and gamma rays. Additionally, we model the spectra of primary electrons, accelerated by supernova remnants, and secondary electrons and positrons produced in hadronic CR proton interactions with the gas. We find that proton spectra above 10 GeV only weakly depend on galactic radius, while they acquire a radial dependence at lower energies due to Coulomb interactions. Radiative losses steepen the spectra of primary CR electrons in the central galactic regions, while diffusive losses dominate in the outskirts. Secondary electrons exhibit a steeper spectrum than primaries because they originate from the transported steeper CR proton spectra. Consistent with Voyager-1 and AMS-02 data, our models (i) show a turnover of proton spectra below GeV energies due to Coulomb interactions so that electrons start to dominate the total particle spectra and (ii) match the shape of the positron fraction up to 10 GeV. We conclude that our steady-state CR modelling in MHD CR galaxy simulations is sufficiently realistic to capture the dominant transport effects shaping their spectra, arguing for a full MHD treatment to accurately model CR transport in the future.

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Mastichiadis, Apostolos, Ioulia Florou, Elina Kefala, Stella S. Boula, and Maria Petropoulou. "A roadmap to hadronic supercriticalities: a comprehensive study of the parameter space for high-energy astrophysical sources." Monthly Notices of the Royal Astronomical Society 495, no. 2 (May 11, 2020): 2458–74. http://dx.doi.org/10.1093/mnras/staa1308.

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ABSTRACT Hadronic supercriticalities are radiative instabilities that appear when large amounts of energy are stored in relativistic protons. When the proton energy density exceeds some critical value, a runaway process is initiated resulting in the explosive transfer of the proton energy into electron–positron pairs and radiation. The runaway also leads to an increase of the radiative efficiency, namely the ratio of the photon luminosity to the injected proton luminosity. We perform a comprehensive study of the parameter space by investigating the onset of hadronic supercriticalities for a wide range of source parameters (i.e. magnetic field strengths of 1 G−100 kG and radii of 1011−1016 cm) and maximum proton Lorentz factors (103−109). We show that supercriticalities are possible for the whole range of source parameters related to compact astrophysical sources, like gamma-ray bursts and cores and jets of active galactic nuclei. We also provide an in-depth look at the physical mechanisms of hadronic supercriticalities and show that magnetized relativistic plasmas are excellent examples of non-linear dynamical systems in high-energy astrophysics.

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11

Blandford, Roger, David Meier, and Anthony Readhead. "Relativistic Jets from Active Galactic Nuclei." Annual Review of Astronomy and Astrophysics 57, no. 1 (August 18, 2019): 467–509. http://dx.doi.org/10.1146/annurev-astro-081817-051948.

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The nuclei of most normal galaxies contain supermassive black holes, which can accrete gas through a disk and become active. These active galactic nuclei (AGNs) can form jets that are observed on scales from astronomical units to megaparsecs and from meter wavelengths to TeV energies. High-resolution radio imaging and multiwavelength/messenger campaigns are elucidating the conditions under which this happens. Evidence is presented that: ▪ Relativistic AGN jets are formed when the black hole spins and the the accretion disk is strongly magnetized, perhaps on account of gas accreting at high latitude beyond the black hole sphere of influence. ▪ AGN jets are collimated close to the black hole by magnetic stress associated with a disk wind. ▪ Higher-power jets can emerge from their galactic nuclei in a relativistic, supersonic, and proton-dominated state, and they terminate in strong, hot spot shocks; lower-power jets are degraded to buoyant plumes and bubbles. ▪ Jets may accelerate protons to EeV energies, which contribute to the cosmic ray spectrum and may initiate pair cascades that can efficiently radiate synchrotron γ-rays. ▪ Jets were far more common when the Universe was a few billion years old and black holes and massive galaxies were growing rapidly. ▪ Jets can have a major influence on their environments, stimulating and limiting the growth of galaxies. The observational prospects for securing our understanding of AGN jets are bright.

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12

HEINZ, SEBASTIAN. "CLUES FOR THE COMPOSITION OF RELATIVISTIC MICROQUASAR JETS." International Journal of Modern Physics D 17, no. 10 (September 2008): 1947–52. http://dx.doi.org/10.1142/s0218271808013613.

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We discuss the evidence for proton loading in relativistic jets from microquasars in light of recent constraints on the jet power. We argue that, both in the case of the Cygnus X-1 jet and the entire ensemble of Galactic microquasars, the evidence points towards a significant contribution to the total kinetic energy flux from cold protons. However, as with all other methods of constraining jet composition (except for the singular case of SS 433), a number of alternative, though maybe less plausible, explanations exist. In light of this continued elusiveness of a single slam-dunk argument for proton loading, the best we can hope for is a continuing accumulation of bits of evidence such as these which will, on the whole, form a preponderance of evidence against pure pair jets.

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13

Fokov, Gennadiy, and Valeriy Kozhemyakin. "On the Calibration of the Cherenkov Detector of Galactic and Solar Cosmic Protons with Energies of 600 MeV and More." ANRI, no. 1 (March 4, 2021): 53–62. http://dx.doi.org/10.37414/2075-1338-2021-104-1-53-62.

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This article discusses a possible approach to creating a calibration technique for the Galactic and Solar Cosmic Proton Cherenkov Detector. The method is based on the Monte Carlo simulation of proton and electron transfer and their generation of Cherenkov photons in the polymethylmethacrylate radiator. It is shown that, under certain conditions, the device calibration with electrons of 9,38 MeV energy is equivalent to the calibration with a 600 MeV proton beam incident laterally on the detector.

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14

Begelman, Mitchell C., Bronislaw Rudak, and Marek Sikora. "Consequences of relativistic proton injection in active galactic nuclei." Astrophysical Journal 362 (October 1990): 38. http://dx.doi.org/10.1086/169241.

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15

Supan, L., G. Castelletti, A. D. Supanitsky, M. G. Burton, G. F. Wong, and C. Braiding. "Natal molecular cloud of SNR Kes 41. Complete characterisation." Astronomy & Astrophysics 619 (November 2018): A108. http://dx.doi.org/10.1051/0004-6361/201833183.

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Using high-resolution data of the 12CO and 13CO (J = 1–0) line emission from the Mopra Southern Galactic Plane CO Survey in conjunction with neutral hydrogen observations from the Southern Galactic Plane Survey (SGPS) and mid-infrared Spitzer data, we have explored the large-scale environment of the supernova remnant Kes 41. On the basis of these data, we identified for the first time the parent cloud of Kes 41 in its whole extension and surveyed the HII regions, masers, and the population of massive young stellar objects in the cloud. The whole unveiled giant cloud, located at the kinematic distance of 12.0 ± 3.6 kpc, whose average total mass and size are ~10–30 × 105 M⊙ and ~ 26′, also shines in γ-rays, as revealed by the Large Area Telescope on board the Fermi satellite. We determined a high average proton density ~500–1000 cm−3 in the large molecular complex, of which protons from the neutral atomic and ionised gases comprise only ~15%.

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16

Loffredo, Filomena, Emanuele Vardaci, Davide Bianco, Antonio Di Nitto, and Maria Quarto. "Protons Interaction with Nomex Target: Secondary Radiation from a Monte Carlo Simulation with Geant4." Applied Sciences 12, no. 5 (March 3, 2022): 2643. http://dx.doi.org/10.3390/app12052643.

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The study of suitable materials to shield astronauts from Galactic Cosmic Rays (GCR) is a topic of fundamental importance. The choice of the material must take into account both the secondary radiation produced by the interaction between primary radiation and material and its shielding ability. The physics case presented here deals with the interaction of a proton beam with a Nomex shield, namely, a target material with a mass thickness of 20 g cm−2. The study was conducted with the simulation code DOSE based on the well-known simulation package Geant4. This article shows the properties of secondary radiations produced in the target by the interaction of a proton beam in an energy range characterizing the GCR spectrum. We observed the production of ions of masses and charges lower than the chemical elements that make up Nomex, and also a significant production of neutrons, protons, and 𝛼 particles.

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Yang, Rui-Zhi, and Yuan Wang. "The diffuse gamma-ray emission toward the Galactic mini starburst W43." Astronomy & Astrophysics 640 (August 2020): A60. http://dx.doi.org/10.1051/0004-6361/202037518.

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In this paper we report the Fermi Large Area Telescope (Fermi-LAT) detection of the γ-ray emission toward the young star forming region W43. Using the latest source catalog and diffuse background models, the extended γ-ray excess is detected with a significance of ~16σ. The γ-ray emission has a spectrum with a photon index of 2.3 ± 0.1. We also performed a detailed analysis of the gas content in this region by taking into account the opacity correction to the HI gas column density. The total cosmic-ray (CR) proton energy is estimated to be on the order of 1048 erg, assuming the γ-rays are produced from the interaction of the accelerated protons and nuclei with the ambient gas. Comparing this region to the other star formation regions in our Galaxy, we find that the CR luminosity is better correlated with the wind power than the star formation rate (SFR). This result suggests that CRs are primarily accelerated by stellar wind in these systems.

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Dey, Rajat K., Animesh Basak, and Sabyasachi Ray. "Diffuse flux of PeV neutrinos from centrifugally accelerated protons in active galactic nuclei." Europhysics Letters 136, no. 6 (December 1, 2021): 69001. http://dx.doi.org/10.1209/0295-5075/ac35bc.

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Abstract Evidence for high-energy astrophysical PeV neutrinos has been found in the IceCube experiment from an analysis with 7.5-year (2010–2017) data. Active galactic nuclei (AGN) are among the most prominent objects in the universe, and are widely speculated to be emitters of ultra-high-energy (UHE) cosmic rays with proton domination. Based on the standard two-step LLCD mechanism of particle acceleration, a transformation of energy occurs from AGN's central super-massive black hole (SMBH) rotation to high-energy protons. Protons can be accelerated up to energies and above, and might generate PeV neutrinos in the energy range through plausible hadronic interactions. The theoretically estimated revised extragalactic diffuse muon neutrino flux employing the “luminosity-dependent density evolution (LDDE)” model for the AGN luminosity function (LF) is found consistent with the IceCube level if only a fraction, of the total bolometric luminosity (BL) of AGN is being realizable to power the PeV neutrinos. In the Λ CDM cosmological framework with the LDDE-modeled LF and photon index distribution, about of the total BL is enough to power the IceCube neutrinos.

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Begelman, Mitchell C., Bronislaw Rudak, and Marek Sikora. "Consequences of Relativistic Proton Injection in Active Galactic Nuclei: Erratum." Astrophysical Journal 370 (April 1991): 791. http://dx.doi.org/10.1086/169863.

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20

An, Q., R. Asfandiyarov, P. Azzarello, P. Bernardini, X. J. Bi, M. S. Cai, J. Chang, et al. "Measurement of the cosmic ray proton spectrum from 40 GeV to 100 TeV with the DAMPE satellite." Science Advances 5, no. 9 (September 2019): eaax3793. http://dx.doi.org/10.1126/sciadv.aax3793.

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The precise measurement of the spectrum of protons, the most abundant component of the cosmic radiation, is necessary to understand the source and acceleration of cosmic rays in the Milky Way. This work reports the measurement of the cosmic ray proton fluxes with kinetic energies from 40 GeV to 100 TeV, with 2 1/2 years of data recorded by the DArk Matter Particle Explorer (DAMPE). This is the first time that an experiment directly measures the cosmic ray protons up to ~100 TeV with high statistics. The measured spectrum confirms the spectral hardening at ~300 GeV found by previous experiments and reveals a softening at ~13.6 TeV, with the spectral index changing from ~2.60 to ~2.85. Our result suggests the existence of a new spectral feature of cosmic rays at energies lower than the so-called knee and sheds new light on the origin of Galactic cosmic rays.

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21

Neronov, A., and D. Semikoz. "Radio-to-Gamma-Ray Synchrotron and Neutrino Emission from Proton–Proton Interactions in Active Galactic Nuclei." JETP Letters 113, no. 2 (January 2021): 69–74. http://dx.doi.org/10.1134/s0021364021020028.

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22

De Benedittis, Antonio. "Proton energy spectrum with the DAMPE experiment." EPJ Web of Conferences 209 (2019): 01030. http://dx.doi.org/10.1051/epjconf/201920901030.

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The DAMPE (DArk Matter Particle Explorer) experiment, in orbit since December 17th 2015, is a space mission whose main purpose is the detection of cosmic electrons and photons up to energies of 10 TeV, in order to identify possible evidence of Dark Matter in their spectra. Furthermore it aims to measure the spectra and the elemental composition of the galactic cosmic rays nuclei up to the energy of hundreds of TeV. The proton analysis and the flux with kinetic energy ranging from 50 GeV up to 100 TeV, at the end of two years of data taking, will be presented and discussed.

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23

Aharonian, F. A. "Proton-synchrotron radiation of large-scale jets in active galactic nuclei." Monthly Notices of the Royal Astronomical Society 332, no. 1 (May 1, 2002): 215–30. http://dx.doi.org/10.1046/j.1365-8711.2002.05292.x.

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24

Mori, Masaki. "The Galactic Diffuse Gamma‐Ray Spectrum from Cosmic‐Ray Proton Interactions." Astrophysical Journal 478, no. 1 (March 20, 1997): 225–32. http://dx.doi.org/10.1086/303785.

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25

Persinger, Michael A. "Annual Fluctuations in Local Photon Counts Reflect Differential Distances from the Galaxy’s Singularity: Astronomical, Chemical and Biology Implications." International Letters of Chemistry, Physics and Astronomy 49 (April 2015): 60–65. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.49.60.

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A conspicuous annual variation in the photon flux density of ~10-12 W·m-2 by a photomultiplier tube housed in a hyperdark ground level setting was within the range expected for the small changes in the earth’s distance per orbit from the energetic entropy (Joules) of the singularity at the center of the galaxy. For the Bekenstein-Hawking relation to be congruent the singularity’s power must reflect the galaxy’s age. The power (W) per volume at the distance of the earth when divided into the peak-to-trough change in photon flux density for minimum-maximum distances from the galactic center converged with the Compton wavelength for an electron. Subsequent calculations indicated that the discrepancy between the magnetic moments of the orbit/spin of the electron and of the proton when the energy associated with the neutral hydrogen line is involved with the Bohr atom also solve for the Compton electron wavelength. The most likely local mechanism to satisfy the hyperfine currents that are in the order of 10-15 A within the width of plasma membrane phenomena would be proton channels when pH ranges from about 5.8 to 7.4 which can occur transiently near neurons. The measured photon flux densities multiplied by known diffusion velocities of protons in water could produce energy levels of ~10-20 J per square unit of time. The results suggest the potential for collapsing de Broglie particle-wave properties of an electron involves energies associated with neuronal action potentials coupled to cognition and that this potential may be spread through the galactic volume as pervasive photon flux densities originating from the singularity at the center.

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Persinger, Michael A. "Annual Fluctuations in Local Photon Counts Reflect Differential Distances from the Galaxy’s Singularity: Astronomical, Chemical and Biology Implications." International Letters of Chemistry, Physics and Astronomy 49 (April 7, 2015): 60–65. http://dx.doi.org/10.56431/p-x78dwz.

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A conspicuous annual variation in the photon flux density of ~10-12 W·m-2 by a photomultiplier tube housed in a hyperdark ground level setting was within the range expected for the small changes in the earth’s distance per orbit from the energetic entropy (Joules) of the singularity at the center of the galaxy. For the Bekenstein-Hawking relation to be congruent the singularity’s power must reflect the galaxy’s age. The power (W) per volume at the distance of the earth when divided into the peak-to-trough change in photon flux density for minimum-maximum distances from the galactic center converged with the Compton wavelength for an electron. Subsequent calculations indicated that the discrepancy between the magnetic moments of the orbit/spin of the electron and of the proton when the energy associated with the neutral hydrogen line is involved with the Bohr atom also solve for the Compton electron wavelength. The most likely local mechanism to satisfy the hyperfine currents that are in the order of 10-15 A within the width of plasma membrane phenomena would be proton channels when pH ranges from about 5.8 to 7.4 which can occur transiently near neurons. The measured photon flux densities multiplied by known diffusion velocities of protons in water could produce energy levels of ~10-20 J per square unit of time. The results suggest the potential for collapsing de Broglie particle-wave properties of an electron involves energies associated with neuronal action potentials coupled to cognition and that this potential may be spread through the galactic volume as pervasive photon flux densities originating from the singularity at the center.

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27

Lazutin, Leonid. "INCREASES IN SCR ENERGETIC PROTON FLUXES ON EARTH AND THEIR RELATION TO SOLAR SOURCES." Solar-Terrestrial Physics 6, no. 4 (December 22, 2020): 40–43. http://dx.doi.org/10.12737/stp-64202006.

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Logachev catalog data for solar cycle 23 has been used to study the dependence of measured increases in solar cosmic rays (SCRs) on solar perturbations. The efficiency of recording the SCR increases, driven by proton acceleration in the corona, on Earth and in its vicinity is shown to depend on power of a solar flare that created a shock wave and on position of the flare on the solar disk. As the particle flux moves along the heliolongitude away from the parent flare, the acceleration efficiency decreases, i.e. the maximum energy of the accelerated particles and their intensity at equal energy decrease. As a result, at a certain distance along a heliolongitude from the parent solar flare, the solar proton flux intensity decreases to the galactic background, and there is no SCR increase detected.

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Aminalragia-Giamini, Sigiava, Ingmar Sandberg, Constantinos Papadimitriou, Ioannis A. Daglis, and Piers Jiggens. "The virtual enhancements − solar proton event radiation (VESPER) model." Journal of Space Weather and Space Climate 8 (2018): A06. http://dx.doi.org/10.1051/swsc/2017040.

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A new probabilistic model introducing a novel paradigm for the modelling of the solar proton environment at 1 AU is presented. The virtual enhancements − solar proton event radiation model (VESPER) uses the European space agency's solar energetic particle environment modelling (SEPEM) Reference Dataset and produces virtual time-series of proton differential fluxes. In this regard it fundamentally diverges from the approach of existing SPE models that are based on probabilistic descriptions of SPE macroscopic characteristics such as peak flux and cumulative fluence. It is shown that VESPER reproduces well the dataset characteristics it uses, and further comparisons with existing models are made with respect to their results. The production of time-series as the main output of the model opens a straightforward way for the calculation of solar proton radiation effects in terms of time-series and the pairing with effects caused by trapped radiation and galactic cosmic rays.

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29

Persinger, Michael A. "Variability of Hubble’s Parameter, Geomagnetic Activity, and Putative Changes in Space-Mass Density: Implications for Terrestrial Cell Growth." International Letters of Chemistry, Physics and Astronomy 53 (July 2015): 137–45. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.53.137.

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The quotient for Planck’s Length divided by the product of Hubble’s parameter and twice the width of the Compton wave length for a proton has been considered a critical increment for the time required for a proton to expand one Planck’s Length. The empirical time of 3.25 ms, found in magnetic field effectiveness for multiple physical and biochemical reactions, requires a local Hubble constant (H) of 58 km·s-1·MPar-1 with a resulting mass density of 0.14 protons per cubic meter. This mass density multiplied by the cube of the galactic orbital velocity is within error measurement of the background photon flux density measured locally by photomultiplier units over the last four years. Regression analyses for the weak positive correlation between Huchra’s annual fluctuations in H and global annual geomagnetic activity over the last 30 years indicated that every 1 nT increase was associated with 0.44 km·s-1·MPar-1 increase in H. The required average density is equivalent to that of the rest mass of the electron. The results and quantitative solutions indicate that the measurement of H is affected by geomagnetic activity and that the time for a proton to expand 1 Planck’s Length can vary over time. Unless earth-based reactions from exposures to pulsed or “quantum well” like magnetic fields that depend upon resonant precision with this value are adjusted appropriately their efficacy could vary significantly.

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30

Persinger, Michael A. "Variability of Hubble’s Parameter, Geomagnetic Activity, and Putative Changes in Space-Mass Density: Implications for Terrestrial Cell Growth." International Letters of Chemistry, Physics and Astronomy 53 (July 1, 2015): 137–45. http://dx.doi.org/10.56431/p-w3lm9u.

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The quotient for Planck’s Length divided by the product of Hubble’s parameter and twice the width of the Compton wave length for a proton has been considered a critical increment for the time required for a proton to expand one Planck’s Length. The empirical time of 3.25 ms, found in magnetic field effectiveness for multiple physical and biochemical reactions, requires a local Hubble constant (H) of 58 km·s-1·MPar-1 with a resulting mass density of 0.14 protons per cubic meter. This mass density multiplied by the cube of the galactic orbital velocity is within error measurement of the background photon flux density measured locally by photomultiplier units over the last four years. Regression analyses for the weak positive correlation between Huchra’s annual fluctuations in H and global annual geomagnetic activity over the last 30 years indicated that every 1 nT increase was associated with 0.44 km·s-1·MPar-1 increase in H. The required average density is equivalent to that of the rest mass of the electron. The results and quantitative solutions indicate that the measurement of H is affected by geomagnetic activity and that the time for a proton to expand 1 Planck’s Length can vary over time. Unless earth-based reactions from exposures to pulsed or “quantum well” like magnetic fields that depend upon resonant precision with this value are adjusted appropriately their efficacy could vary significantly.

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Cirkovic, Milan, and I. Damjanov. "On determination of the cosmic ray flux using molecular hydrogen absorption lines." Serbian Astronomical Journal, no. 167 (2003): 15–20. http://dx.doi.org/10.2298/saj0367015c.

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We outline a procedure for estimating the cosmic ray flux at remote locations where molecular hydrogen absorption lines have been detected. The method relies on several assumptions whose validity in the local Galactic ISM has been independently verified, so it might be useful for much less accessible objects, especially damped Ly? absorption systems. Since most of low-energy cosmic rays in the Galactic environment are thought to originate in supernovae remnants, the link to the rate of high-mass star formation could in principle, be established. We applied the method to a particular case of high redshift damped Ly? absorption system towards 0528?250 and obtained an estimate of proton density and some useful constraints.

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32

Takahashi, Yoshiyuki. "Chemical Composition of High-Energy Cosmic-Ray Nuclei and its Possible Origin in Type-II Supernova." International Astronomical Union Colloquium 108 (1988): 444–45. http://dx.doi.org/10.1017/s0252921100094343.

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High energy cosmic ray spectrum has been known to have an interesting bump in the energy range 1014 − 1016 eV. Various models to explain the spectral break in this energy range have been so far proposed; which incorporate either a large-scale termination of galactic wind, shocks with greater age and spatial extent associated with hypothetical super-bubbles powered by multiple supernovae, intersection of two quantum-gravitational components, extra-galactic component, red-shift of big-bang remnant, or a proton component from pulsars. More recently, their possible origin in type-II supernovae with magnetic acceleration mechanism is proposed by considering direct observational results of chemical composition near the bump regime of cosmic ray spectrum.

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Song, Xiaojian, Xi Luo, Marius S. Potgieter, XinMing Liu, and Zekun Geng. "A Numerical Study of the Solar Modulation of Galactic Protons and Helium from 2006 to 2017." Astrophysical Journal Supplement Series 257, no. 2 (December 1, 2021): 48. http://dx.doi.org/10.3847/1538-4365/ac281c.

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Abstract With continuous measurements from space-borne cosmic-ray detectors such as AMS-02 and PAMELA, precise spectra of galactic cosmic rays over the 11 yr solar cycle have become available. For this study, we utilize proton and helium spectra below 10 GV from these missions from 2006 to 2017 to construct a cosmic-ray transport model for a quantitative study of the processes of solar modulation. This numerical model is based on Parker’s transport equation, which includes four major transport processes. The Markov Chain Monte Carlo method is utilized to search the relevant parameter space related to the drift and the diffusion coefficients by reproducing and fitting the mentioned observed spectra. The resulting best-fit normalized χ 2 is mainly less than 1. It is found that (1) when reproducing these observations the parameters required for the drift and diffusion coefficients exhibit a clear time dependence, with the magnitude of the diffusion coefficients anticorrelated with solar activity; (2) the rigidity dependence of the resulting mean free paths varies with time, and their rigidity dependence at lower rigidity can even have a larger slope than at higher rigidity; (3) using a single set of modulation parameters for each pair of observed proton and helium spectra, most spectra are reproduced within observational uncertainty; and (4) the simulated proton-to-helium flux ratio agrees with the observed values in terms of its long-term time dependence, although some discrepancy exists, and the difference is mostly coming from the underestimation of proton flux.

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34

Parenti, Andrea. "Galactic cosmic rays: latest results from the DAMPE mission." Journal of Physics: Conference Series 2429, no. 1 (February 1, 2023): 012003. http://dx.doi.org/10.1088/1742-6596/2429/1/012003.

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Abstract The space-based DAMPE (DArk Matter Particle Explorer) particle detector has been taking data for more than 6 years since its successful launch in December 2015. Its main scientific goals include the indirect search of Dark Matter signatures in the cosmic lepton spectra, the study of Galactic Cosmic Rays up to energies of hundreds of TeV and high-energy gamma ray astronomy. This talk will focus on Galactic Cosmic Rays and the measurement of their spectra, fundamental to investigate the mechanisms of acceleration at their sources and propagation through the interstellar medium. The most recent results on Proton and Helium, which revealed new spectral features, will be highlighted. Ongoing analyses regarding the cosmic ray light component, medium and heavy mass nuclei will be discussed alongside studies on the so-called secondary cosmic rays.

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35

Biermann, P. L., L. I. Caramete, A. Meli, B. N. Nath, E. S. Seo, V. de Souza, and J. Becker Tjus. "Cosmic ray transport and anisotropies to high energies." ASTRA Proceedings 2 (October 2, 2015): 39–44. http://dx.doi.org/10.5194/ap-2-39-2015.

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Abstract. A model is introduced, in which the irregularity spectrum of the Galactic magnetic field beyond the dissipation length scale is first a Kolmogorov spectrum k-5/3 at small scales λ = 2 π/k with k the wave-number, then a saturation spectrum k-1, and finally a shock-dominated spectrum k-2 mostly in the halo/wind outside the Cosmic Ray disk. In an isotropic approximation such a model is consistent with the Interstellar Medium (ISM) data. With this model we discuss the Galactic Cosmic Ray (GCR) spectrum, as well as the extragalactic Ultra High Energy Cosmic Rays (UHECRs), their chemical abundances and anisotropies. UHECRs may include a proton component from many radio galaxies integrated over vast distances, visible already below 3 EeV.

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36

Kecskeméty, K., Yu I. Logachev, M. A. Zeldovich, and J. Kóta. "MODULATION OF THE GALACTIC LOW-ENERGY PROTON SPECTRUM IN THE INNER HELIOSPHERE." Astrophysical Journal 738, no. 2 (August 24, 2011): 173. http://dx.doi.org/10.1088/0004-637x/738/2/173.

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Qin, G., L. L. Zhao, and H. C. Chen. "DESPIKING OF SPACECRAFT ENERGETIC PROTON FLUX TO STUDY GALACTIC COSMIC-RAY MODULATION." Astrophysical Journal 752, no. 2 (June 5, 2012): 138. http://dx.doi.org/10.1088/0004-637x/752/2/138.

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38

Sinitsyna, Vera Yu, Vera G. Sinitsyna, and Yurii I. Stozhkov. "Red Dwarfs as Sources of Cosmic Rays." EPJ Web of Conferences 260 (2022): 11033. http://dx.doi.org/10.1051/epjconf/202226011033.

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The Pamela, Fermi, AMS-02 spectrometer experimental data cannot be explained using the diffusive models of propagation of cosmic-rays accelerated at the supernova shocks and require the existence of nearby sources of cosmic rays at the distances less than one kpc. These sources could explain the growth of the ratio of galactic positrons to electrons with an energy increase, the complex dependence of the exponent of the proton and alpha spectra on the energy, the cosmic ray anomaly component origin. We consider active dwarf stars as possible sources of galactic cosmic rays in the energy range up to ~ 1014 eV. The generation of high-energy cosmic rays should be accompanied by high-energy gamma-ray emission, which may be detected. The TeV gamma-ray emission mostly of flaring type from active red dwarf stars V388 Cas, V547 Cas, V780 Tau, V962 Tau, V1589 Cyg, GJ 3684, GJ 1078 and GL 851.1 was detected recently with SHALON long-term observations. This result confirms that active dwarf stars are also the sources of high-energy galactic cosmic rays.

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39

Okpala, Kingsley Chukwudi, Francisca Nneka Okeke, and Anselem Ikechukwu Ugwuoke. "Cosmic ray modulation in high and middle latitudes during solar cycles 22 and 23." Canadian Journal of Physics 93, no. 1 (January 2015): 100–104. http://dx.doi.org/10.1139/cjp-2014-0290.

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Galactic cosmic rays are modulated in the heliosphere primarily by the global merged interaction regions with intense magnetic fields, which leads to a decrease in galactic cosmic rays throughout the heliosphere. Using long-term averages of solar wind (SW) component parameters in addition to cosmic ray count rates of four neutron monitors with different rigidity cutoffs, we analyzed the effect of these SW components on the count rates under different interplanetary magnetic field (IMF) disturbance levels. From first-order partial correlation, we found that the IMF-B was the most dominant modulating parameter, especially during quiet conditions and the SW dynamic pressure was more effective during disturbed conditions. The influence of more subtle parameters like wind speed, Bz component, and proton density were masked by these dominant parameters: IMF total B, and SW dynamic pressure.

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Jaupart, Étienne, Étienne Parizot, and Denis Allard. "Contribution of the Galactic centre to the local cosmic-ray flux." Astronomy & Astrophysics 619 (November 2018): A12. http://dx.doi.org/10.1051/0004-6361/201833683.

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Context. Recent observations of unexpected structures in the Galactic cosmic ray (GCR) spectrum and composition, as well as growing evidence for episodes of intense dynamical activity in the inner regions of the Galaxy, call for an evaluation of the high-energy particle acceleration associated with such activity and its potential impact on the global GCR phenomenology. Aims. We investigate whether particles accelerated during high-power episodes around the Galactic centre can account for a significant fraction of the observed GCRs, or, conversely, what constraints can be derived regarding their Galactic transport if their contributions are negligible. Methods. Particle transport in the Galaxy is described with a two-zone analytical model. We solved for the contribution of a Galactic centre cosmic-Ray (GCCR) source using Green functions and Bessel expansion, and discussed the required injection power for these GCCRs to influence the global GCR phenomenology at Earth. Results. We find that, with standard parameters for particle propagation in the galactic disk and halo, the GCCRs can make a significant or even dominant contribution to the total CR flux observed at Earth. Depending on the parameters, such a source can account for both the observed proton flux and boron-to-carbon ratio (in the case of a Kraichnan-like scaling of the diffusion coefficient), or potentially produce spectral and composition features. Conclusions. Our results show that the contribution of GCCRs cannot be neglected a priori, and that they can influence the global GCR phenomenology significantly, thereby calling for a reassessement of the standard inferences from a scenario where GCRs are entirely dominated by a single type of sources distributed throughout the Galactic disk.

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41

Chernyshov, D. O., V. A. Dogiel, A. V. Ivlev, A. D. Erlykin, and A. M. Kiselev. "Formation of the Cosmic-Ray Halo: The Role of Nonlinear Landau Damping." Astrophysical Journal 937, no. 2 (October 1, 2022): 107. http://dx.doi.org/10.3847/1538-4357/ac8f42.

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Abstract We present a nonlinear model of a self-consistent Galactic halo, where the processes of cosmic-ray (CR) propagation and excitation/damping of MHD waves are included. The MHD turbulence that prevents CR escape from the Galaxy is entirely generated by the resonant streaming instability. The key mechanism controlling the halo size is the nonlinear Landau (NL) damping, which suppresses the amplitude of MHD fluctuations and, thus, makes the halo larger. The equilibrium turbulence spectrum is determined by a balance of CR excitation and NL damping, which sets the regions of diffusive and advective propagation of CRs. The boundary z cr(E) between the two regions is the halo size, which slowly increases with the energy. For the vertical magnetic field of ∼1 μG, we estimate z cr ∼ 1 kpc for GeV protons. The derived proton spectrum is in a good agreement with observational data.

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42

Mifsud, Duncan V., Péter Herczku, Béla Sulik, Zoltán Juhász, István Vajda, István Rajta, Sergio Ioppolo, Nigel J. Mason, Giovanni Strazzulla, and Zuzana Kaňuchová. "Proton and Electron Irradiations of CH4:H2O Mixed Ices." Atoms 11, no. 2 (January 22, 2023): 19. http://dx.doi.org/10.3390/atoms11020019.

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The organic chemistry occurring in interstellar environments may lead to the production of complex molecules that are relevant to the emergence of life. Therefore, in order to understand the origins of life itself, it is necessary to probe the chemistry of carbon-bearing molecules under conditions that simulate interstellar space. Several of these regions, such as dense molecular cores, are exposed to ionizing radiation in the form of galactic cosmic rays, which may act as an important driver of molecular destruction and synthesis. In this paper, we report the results of a comparative and systematic study of the irradiation of CH4:H2O ice mixtures by 1 MeV protons and 2 keV electrons at 20 K. We demonstrate that our irradiations result in the formation of a number of new products, including both simple and complex daughter molecules such as C2H6, C3H8, C2H2, CH3OH, CO, CO2, and probably also H2CO. A comparison of the different irradiation regimes has also revealed that proton irradiation resulted in a greater abundance of radiolytic daughter molecules compared to electron irradiation, despite a lower radiation dose having been administered. These results are important in the context of the radiation astrochemistry occurring within the molecular cores of dense interstellar clouds, as well as on outer Solar System objects.

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43

Van Dyke Dixon, W., Mark Hurwitz, and Stuart Bowyer. "ORFEUS-I Observations of Molecular Hydrogen in the Galactic Disk." International Astronomical Union Colloquium 166 (1997): 261–64. http://dx.doi.org/10.1017/s0252921100071086.

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AbstractWe present measurements of interstellar H2 absorption lines in the continuum spectra of seven early-type stars in the Galactic disk at distances between 1 and 4 kpc. The spectra, obtained with the Berkeley EUV/FUV spectrometer on the ORFEUS telescope in 1993 September, have a resolution of 3000 and statistical signal-to-noise ratios between 20 and 80. We determine column densities for each observed rotational level and derive mean excitation temperatures and proton density limits for the H2 clouds along each line of sight. The gross properties of the H2-bearing clouds (e.g., column density, spatial density, cloud size) are consistent with those derived from Copernicus observations, though our lines of sight are much longer, with lower average reddenings and neutral gas densities. We find that the molecular fraction of the neutral hydrogen remains ~ 0.1 out to distances of 4 kpc in the Galactic disk.

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44

Kopp, A., I. Büsching, M. S. Potgieter, and R. D. Strauss. "A stochastic approach to Galactic proton propagation: Influence of the spiral arm structure." New Astronomy 30 (July 2014): 32–37. http://dx.doi.org/10.1016/j.newast.2014.01.006.

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45

Cook, W. R., A. C. Cummings, J. R. Cummings, T. L. Garrard, B. Kecman, R. A. Mewaldt, R. S. Selesnick, et al. "PET: a proton/electron telescope for studies of magnetospheric, solar, and galactic particles." IEEE Transactions on Geoscience and Remote Sensing 31, no. 3 (May 1993): 565–71. http://dx.doi.org/10.1109/36.225523.

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46

Arcadi, Giorgio, Farinaldo S. Queiroz, and Clarissa Siqueira. "The semi-Hooperon: Gamma-ray and anti-proton excesses in the Galactic Center." Physics Letters B 775 (December 2017): 196–205. http://dx.doi.org/10.1016/j.physletb.2017.10.065.

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47

Zhang, Yiran, Siming Liu, and Houdun Zeng. "A three-component model for cosmic ray spectrum and dipole anisotropy." Monthly Notices of the Royal Astronomical Society 511, no. 4 (February 21, 2022): 6218–24. http://dx.doi.org/10.1093/mnras/stac470.

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ABSTRACT Using a three-component, multiscale diffusion model, we show that the cosmic ray (CR) proton and helium spectra and the dipole anisotropy can be explained with reasonable parameters. The model includes a nearby source associated with the supernova remnant (SNR) that gave rise to the Geminga pulsar, a source at the Galactic Centre, and a component associated with the Galactic disc. The CR flux below TeV is dominated by the disc component. The centre source with a continuous injection of CRs starting about 18 Myr ago is needed to explain the anisotropy above 100 TeV. With the assumption of universal CR spectra injected by all SNRs, the nearby source can produce a TeV spectral bump observed at Earth via slow diffusion across the interstellar magnetic field, which needs to have an angle θ ≈ 5° between the field line and the line of sight towards the source, and have weak magnetic turbulence with the Alfvén Mach number MA ≈ 0.1. Considering the modulation of the Galactic-scale anisotropy by this magnetic field, in a quasi-local approach the field may be directed at a right ascension about −90° and a declination about −7.4° in the equatorial coordinate system.

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Windridge, D., S. Phillipps, and M. Birkinshaw. "Measures of Galactic and Intergalactic Mass in Clusters." Symposium - International Astronomical Union 179 (1998): 266–67. http://dx.doi.org/10.1017/s0074180900128724.

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If a galaxy cluster's X-ray gas distribution follows an isothermal polytropic β model, we may write the electron radial density distribution as; ne = ne0(1 + r2/rc2)–3/2β, rc being the core radius and ne0 the central electron density. This may be related to both an X-ray surface brightness distribution and a Sunyaev-Zel'dovich effect distribution (Sarazin 1986). Fitting to observational data then enables us to constrain the value of β. The normalisation value, ne0, to obtain a total mass estimate is calculated via the relationship between the X-ray and S-Z distribution normalisation constants, and the gas temperature and spectral emissivity parameters from fits to the X-ray spectrum. We are then in a position to evaluate ne(r) and its integral; the total electron gas mass. If we can further assume that there exists a simple ratio between the electron and proton number densities within the gas, we may straightforwardly posit a value for the total gas mass. An additional method of determining the polytropic gas index exists, with optical constraints on the galactic velocity dispersion, through the relation; β = μmHσz2/kBTe. Studies at optical, as well as X-ray and radio wavelengths are thus useful as a corroborative measure in determining the total gas mass.

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Maurchev, Evgeniy, Evgeniya Mikhalko, Yuriy Balabin, Aleksey Germanenko, and Boris Gvozdevsky. "Estimated equivalent radiation dose at different altitudes in Earth’s atmosphere." Solar-Terrestrial Physics 8, no. 3 (September 30, 2022): 27–31. http://dx.doi.org/10.12737/stp-83202204.

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The paper reports the results of simulation of cosmic ray proton transport through Earth’s atmosphere. The main objective of this work is to obtain characteristics of secondary particle fluxes at different altitudes and to convert them to equivalent dose values. The technique for the conversion is based on numerical simulation of interaction between the particles and an anthropomorphic phantom. The paper examines two cases, using a model source of primary proton spectra as input parameters, which correspond to both purely galactic cosmic rays and solar cosmic rays. The computational results are tabulated for the altitude range from 0 km to 11 km above sea level; the upper range value corresponds to the flight altitude of civilian airliners. These results are shown to agree well with the results obtained by other research teams.

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Maurchev, Evgeniy, Evgeniya Mikhalko, Yuriy Balabin, Aleksey Germanenko, and Boris Gvozdevsky. "Estimated equivalent radiation dose at different altitudes in Earth’s atmosphere." Solnechno-Zemnaya Fizika 8, no. 3 (September 30, 2022): 29–34. http://dx.doi.org/10.12737/szf-83202204.

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The paper reports the results of simulation of cosmic ray proton transport through Earth’s atmosphere. The main objective of this work is to obtain characteristics of secondary particle fluxes at different altitudes and to convert them to equivalent dose values. The technique for the conversion is based on numerical simulation of interaction between the particles and an anthropomorphic phantom. The paper examines two cases, using a model source of primary proton spectra as input parameters, which correspond to both purely galactic cosmic rays and solar cosmic rays. The computational results are tabulated for the altitude range from 0 km to 11 km above sea level; the upper range value corresponds to the flight altitude of civilian airliners. These results are shown to agree well with the results obtained by other research teams.

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Journal articles on the topic 'Galactic proton'

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