Estimation of elemental abundances of heavy cosmic-ray primaries at the top of the atmosphere using plastic emulsion chamber and the derived source spectrum from the steady-state leaky box model

1995 ◽  
Vol 18 (2) ◽  
pp. 161-175 ◽  
Author(s):  
D. P. Bhattacharyya ◽  
R. Majumdar ◽  
B. Basu ◽  
P. Pal ◽  
M. Fujii
Keyword(s):  
Steady State ◽  
Cosmic Ray ◽  
Box Model ◽  
Source Spectrum ◽  
Emulsion Chamber ◽  
Elemental Abundances

Energy spectra of secondary gamma rays at different atmospheric depths

1979 ◽  
Vol 57 (4) ◽  
pp. 582-585 ◽  
Author(s):  
D. P. Bhattacharyya ◽  
R. K. Roychoudhury
Keyword(s):  
Storage Ring ◽  
Spectral Range ◽  
Gamma Rays ◽  
Space Flight ◽  
Gamma Ray ◽  
Energy Spectra ◽  
Source Spectrum ◽  
Emulsion Chamber ◽  
Intersecting Storage Ring ◽  
Nucleon Spectrum

The CERN Intersecting Storage Ring (ISR) data for p + p → π0 + X inclusive reaction have been used to derive the spectrum of secondary gamma rays at the top of the atmosphere. The measured primary nucleon spectrum of the Goddard Space Flight Group has been taken as a nucleon source spectrum. Using the cascade theory, the gamma ray spectra at the atmospheric depths 540, 650, and 735 g cm−2 have been calculated. The results are approximately in accord with the emulsion chamber data at Mt. Chacaltaya, Mt. Norikura, and Mt. Fuji in the spectral range 0.2–4 TeV.

scholarly journals Cosmic rays and non-thermal emission in simulated galaxies: III. probing cosmic ray calorimetry with radio spectra and the FIR-radio correlation

2021 ◽  
Author(s):  
Maria Werhahn ◽  
Christoph Pfrommer ◽  
Philipp Girichidis
Keyword(s):  
Steady State ◽  
Star Formation ◽  
Thermal Emission ◽  
High Redshift ◽  
Formation Rate ◽  
Cosmic Ray ◽  
Far Infrared ◽  
Secondary Emission ◽  
Synchrotron Emission ◽  
Halo Masses

Abstract An extinction-free estimator of the star-formation rate (SFR) of galaxies is critical for understanding the high-redshift universe. To this end, the nearly linear, tight correlation of far-infrared (FIR) and radio luminosity of star-forming galaxies is widely used. While the FIR is linked to massive star formation, which also generates shock-accelerated cosmic ray (CR) electrons and radio synchrotron emission, a detailed understanding of the underlying physics is still lacking. Hence, we perform three-dimensional magneto-hydrodynamical (MHD) simulations of isolated galaxies over a broad range of halo masses and SFRs using the moving-mesh code Arepo, and evolve the CR proton energy density self-consistently. In post-processing, we calculate the steady-state spectra of primary, shock-accelerated and secondary CR electrons, which result from hadronic CR proton interactions with the interstellar medium. The resulting total radio luminosities correlate with the FIR luminosities as observed and are dominated by primary CR electrons if we account for anisotropic CR diffusion. The increasing contribution of secondary emission up to 30 per cent in starbursts is compensated by the larger bremsstrahlung and Coulomb losses. CR electrons are in the calorimetric limit and lose most of their energy through inverse Compton interactions with star-light and cosmic microwave background (CMB) photons while less energy is converted to synchrotron emission. This implies steep steady-state synchrotron spectra in starbursts. Interestingly, we find that thermal free–free emission flattens the total radio spectra at high radio frequencies and reconciles calorimetric theory with observations while free–free absorption explains the observed low-frequency flattening towards the central regions of starbursts.

scholarly journals Modeling of High Nanoparticle Exposure in an Indoor Industrial Scenario with a One-Box Model

2019 ◽  
Vol 16 (10) ◽  
pp. 1695 ◽  
Author(s):  
Carla Ribalta ◽  
Antti J. Koivisto ◽  
Apostolos Salmatonidis ◽  
Ana López-Lilao ◽  
Eliseo Monfort ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Steady State ◽  
Thermal Spraying ◽  
State Equation ◽  
Convolution Theorem ◽  
Box Model ◽  
Emission Rates ◽  
Mass Balance Models ◽  
Improved Performance ◽  
Occupational Settings

Mass balance models have proved to be effective tools for exposure prediction in occupational settings. However, they are still not extensively tested in real-world scenarios, or for particle number concentrations. An industrial scenario characterized by high emissions of unintentionally-generated nanoparticles (NP) was selected to assess the performance of a one-box model. Worker exposure to NPs due to thermal spraying was monitored, and two methods were used to calculate emission rates: the convolution theorem, and the cyclic steady state equation. Monitored concentrations ranged between 4.2 × 104–2.5 × 105 cm−3. Estimated emission rates were comparable with both methods: 1.4 × 1011–1.2 × 1013 min−1 (convolution) and 1.3 × 1012–1.4 × 1013 min−1 (cyclic steady state). Modeled concentrations were 1.4-6 × 104 cm−3 (convolution) and 1.7–7.1 × 104 cm−3 (cyclic steady state). Results indicated a clear underestimation of measured particle concentrations, with ratios modeled/measured between 0.2–0.7. While both model parametrizations provided similar results on average, using convolution emission rates improved performance on a case-by-case basis. Thus, using cyclic steady state emission rates would be advisable for preliminary risk assessment, while for more precise results, the convolution theorem would be a better option. Results show that one-box models may be useful tools for preliminary risk assessment in occupational settings when room air is well mixed.

scholarly journals A Model of the Chemistry in the Neutral Shell of a Planetary Nebula

1993 ◽  
Vol 155 ◽  
pp. 221-221
Author(s):  
S. N. Gouldsworthy ◽  
D. R. Flower
Keyword(s):  
Planetary Nebula ◽  
Chemical Species ◽  
Cosmic Ray ◽  
Large Set ◽  
Spectral Emission ◽  
Two Photon ◽  
Elemental Abundances ◽  
Cosmic Ray Interactions ◽  
Planck Spectrum ◽  
Region Data

A model of the neutral region of a planetary nebula has been constructed, building on an existing program (Abgrall et al. 1992, Astr. Astrophys. 253, 525). It incorporates a large set of equations governing the formation and destruction of molecular species and also covers photo-dissociation/ionization reactions and cosmic ray interactions. The radiation field impinging on the nebula is modelled as a 105 K diluted Planck spectrum, truncated below 91.2 nm, augmented by spectral emission lines from the ionized region (data from G. Stasinska, private communication) and the hydrogen (2s→1s) two-photon continuum. The chemical species involved in the reactions are composed of seven elements — H, He, C, O, N, S and Fe — with H and He dominating the elemental abundances. The model considers a chemical environment which is carbon-rich (i.e. C/O > 1).

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