Cosmic ray astrophysics (history and general review)

Ginzburg, Vitalii L.

doi:10.1070/pu1996v039n02abeh000132

Cited by 31 publications

(6 citation statements)

References 67 publications

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“…High-energy hadronic particles heat the media along their propagation paths by collisional ionisation and hadronic interactions, with such action of cosmic rays (CRs) having been observed close-by in the Earth's atmosphere (see e.g. Ginzburg 1996;Kotera & Olinto 2011, for reviews). A substantial fraction of the energetic CRs detected on Earth are protons (Abbasi et al 2010), and their origins are likely to be extragalactic.…”

Section: Introductionmentioning

confidence: 99%

Interactions between ultra-high-energy particles and protogalactic environments

Owen

Jacobsen

et al. 2018

Monthly Notices of the Royal Astronomical Society

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We investigate the interactions of energetic hadronic particles (cosmic ray protons) with photons and baryons in protogalactic environments, where the target photons are supplied by the first generations of stars to form in the galaxy and the cosmological microwave background, while the target baryons are the interstellar and circumgalactic medium. We show that pair-production and photo-pion processes are the dominant interactions at particle energies above 10 19 eV, while pp-interaction pion-production dominates at the lower energies in line with expectations from, for example γ-ray observations of star-forming galaxies and dense regions of our own galaxy's interstellar medium. We calculate the path lengths for the interaction channels and determine the corresponding rates of energy deposition. We have found that protogalactic magnetic fields and their evolution can significantly affect the energy transport and energy deposition processes of cosmic rays. Within a Myr after the onset of star-formation the magnetic field in a protogalaxy could attain a strength sufficient to confine all but the highest energy particles within the galaxy. This enhances the cosmic ray driven self-heating of the protogalaxy to a rate of around 10 −24 erg cm −3 s −1 for a galaxy with strong star-forming activity that yields 1 core collapse SN event per year. This heating power exceeds even that due to radiative emission from the protogalaxy's stellar populations. However, in a short window before the protogalaxy is fully magnetised, energetic particles could stream across the galaxy freely, delivering energy into the circumgalactic and intergalactic medium.

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Section: Introductionmentioning

confidence: 99%

Interactions between ultra-high-energy particles and protogalactic environments

Owen

Jacobsen

et al. 2018

Monthly Notices of the Royal Astronomical Society

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“…Cosmic rays can be viewed as complementary messengers in multi-messenger astronomy, alongside photons, neutrinos and gravitational waves (Branchesi, 2016). See Ginzburg (1996), Kotera and Olinto (2011) and Castellina and Donato (2013), for recent reviews of the role of cosmic rays in astrophysics. More locally cosmic rays are a probe of solar physics (e.g.…”

Section: Introductionmentioning

confidence: 99%

First results from the LUCID-Timepix spacecraft payload onboard the TechDemoSat-1 satellite in Low Earth Orbit

Furnell

Shenoy

Fox

et al. 2019

Advances in Space Research

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The Langton Ultimate Cosmic ray Intensity Detector (LUCID) is a payload onboard the satellite TechDemoSat-1, used to study the radiation environment in Low Earth Orbit (∼635km). LUCID operated from 2014 to 2017, collecting over 2.1 million frames of radiation data from its five Timepix detectors on board. LUCID is one of the first uses of the Timepix detector technology in open space, with the data providing useful insight into the performance of this technology in new environments. It provides high-sensitivity imaging measurements of the mixed radiation field, with a wide dynamic range in terms of spectral response, particle type and direction. The data has been analysed using computing resources provided by GridPP, with a new machine learning algorithm that uses the Tensorflow framework. This algorithm provides a new approach to processing Medipix data, using a training set of human labelled tracks, providing greater particle classification accuracy than other algorithms. For managing the LUCID data, we have developed an online platform called Timepix Analysis Platform at School (TAPAS). This provides a swift and simple way for users to analyse data that they collect using Timepix detectors from both LUCID and other experiments. We also present some possible future uses of the LUCID data and Medipix detectors in space.

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“…Locally, the CR energy density is of order 10 −12 ergs cm −3 . Observations of the light elements produced by spallation reactions show that the lifetime τ CR, disk of relativistic protons in the Galactic disk is of order τ CR, disk ∼ 1.5 × 10 7 yrs (Yanasak et al 2001), while the lifetime in the Galactic halo τ CR, halo is close to 10 8 years (e.g., Ginzburg 1996). This enables us to estimate the CR luminosity of the Galaxy as L CR ∼ 4 × 10 40 ergs s −1 , with a diffusion coefficient κ inside the disk of …”

Section: Comparison With the Canonical Cr Powerlaw Componentmentioning

confidence: 99%

Cosmic rays from microquasars: A narrow component to the CR spectrum?

Heinz

Sunyaev

2002

A&A

152

142

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Abstract. We propose that relativistic Galactic jets like those observed in GRS 1915+105 and GRO J1655-40 may produce a small but measurable contribution to the cosmic ray (CR) spectrum. If these jets contain cold protons and heavy ions (as in the case of SS433), it is plausible that this component will consist of a narrow spectral feature, with a mean particle energy corresponding roughly to the bulk kinetic particle energy in the beam, Γ jet m p c 2 . Based on the current estimates of Γ jet , this feature will fall into the range of 3-10 GeV. The presence of several sources with different Γ jet will lead to the superposition of several such peaks. In addition to the narrow peaks, diffusive particle acceleration should also produce a powerlaw, whose low energy cutoff at or above Γ 2 jet m p c 2 would be visible as an additional spectral feature. The large metallicities measured in several binary companions of jet sources suggest that this CR component could have an anomalous composition compared to the bulk Galactic CR spectrum. We provide estimates of the effects of adiabatic losses which are the greatest challenge to models of narrow band CR production in microquasar jets. While the total energy contained in the microquasar CR component is highly uncertain, the local CR spectrum in the vicinity of any microquasar should be severely affected. The upcoming AMS 02 experiment will be able probe the low energy CR spectrum for such components and for composition anomalies. The spectrally peculiar gamma-ray emission produced by interaction of the ISM with CRs surrounding microquasars might be detectable by GLAST. If the presence of a microquasar CR proton component can be ruled out observationally, this argument could be turned around in favor of electron-positron jets. We show that existing OSSE/GRO and future INTEGRAL data on the Galactic 511 keV line flux put interesting constraints on the particle content of microquasar jets. The process of CR production in relativistic flows inside the Galaxy is fundamentally different from the standard picture of CR production in nonrelativistic shocks in supernova remnants, because the particles injected by a relativistic flow are already relativistic, without any need for diffusive acceleration.

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Cosmic ray astrophysics (history and general review)

Cited by 31 publications

References 67 publications

Interactions between ultra-high-energy particles and protogalactic environments

Interactions between ultra-high-energy particles and protogalactic environments

First results from the LUCID-Timepix spacecraft payload onboard the TechDemoSat-1 satellite in Low Earth Orbit

Cosmic rays from microquasars: A narrow component to the CR spectrum?

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