Remarks on the Role of Pulsars in Cosmic Ray Production

1971 ◽  
pp. 737-739 ◽  
Author(s):  
V. L. Ginzburg
Keyword(s):  
Cosmic Ray

scholarly journals The role of radiolysis in the modelling of C2H4O2 isomers and dimethyl ether in cold dark clouds

2020 ◽  
Vol 500 (3) ◽  
pp. 3414-3424
Author(s):  
Alec Paulive ◽  
Christopher N Shingledecker ◽  
Eric Herbst
Keyword(s):  
Gas Phase ◽  
Dimethyl Ether ◽  
Recent Observation ◽  
Cosmic Ray ◽  
Thermal Method ◽  
Dark Clouds ◽  
Ice Surface ◽  
Dust Grain ◽  
Complex Organic

ABSTRACT Complex organic molecules (COMs) have been detected in a variety of interstellar sources. The abundances of these COMs in warming sources can be explained by syntheses linked to increasing temperatures and densities, allowing quasi-thermal chemical reactions to occur rapidly enough to produce observable amounts of COMs, both in the gas phase, and upon dust grain ice mantles. The COMs produced on grains then become gaseous as the temperature increases sufficiently to allow their thermal desorption. The recent observation of gaseous COMs in cold sources has not been fully explained by these gas-phase and dust grain production routes. Radiolysis chemistry is a possible non-thermal method of producing COMs in cold dark clouds. This new method greatly increases the modelled abundance of selected COMs upon the ice surface and within the ice mantle due to excitation and ionization events from cosmic ray bombardment. We examine the effect of radiolysis on three C2H4O2 isomers – methyl formate (HCOOCH3), glycolaldehyde (HCOCH2OH), and acetic acid (CH3COOH) – and a chemically similar molecule, dimethyl ether (CH3OCH3), in cold dark clouds. We then compare our modelled gaseous abundances with observed abundances in TMC-1, L1689B, and B1-b.

scholarly journals The Role of Flare Stars in Cosmic-ray Origin

1995 ◽  
Vol 151 ◽  
pp. 185-192
Author(s):  
Maurice M. Shapiro
Keyword(s):  
Alternative Hypothesis ◽  
Cosmic Ray ◽  
Optical Data ◽  
Seed Particles ◽  
Cosmic Ray Acceleration ◽  
The Galaxy ◽  
Flare Stars ◽  
Far Ultraviolet ◽  
Ultraviolet Observations

AbstractSupernovae and their expanding shock fronts are evidently the main agents of cosmic-ray acceleration. The thermal gas in the interstellar medium has been regarded as the reservoir of seed particles destined to become cosmic-ray nuclei. This assumption is, however, at variance with the source composition of galactic cosmic iays. In an alternative hypothesis, the seed particles are injected into the interstellar material as suprathermal seed ions, and it has been surmised that flare stars provide the initial boost. We find that the dMe and dKe stars are probably the principal sources of cosmic-ray seed particles. Most stars in the Galaxy are red dwarfs and many of these flares much more powerfully and frequently than solar flares. Augmenting the optical data, recent X-ray and far-ultraviolet observations now permit a better estimate of the energy budget. Altogether, dMe and dKe stars seem to be the most promising class of cosmic-ray injectors.

scholarly journals Volcanoes in Italy and the role of muon radiography

2018 ◽  
Vol 377 (2137) ◽  
pp. 20180050 ◽  
Author(s):  
Raffaello D'Alessandro ◽  
F. Ambrosino ◽  
G. Baccani ◽  
L. Bonechi ◽  
M. Bongi ◽  
...  
Keyword(s):  
Imaging Technique ◽  
Cosmic Ray ◽  
Final Phase ◽  
Rock Density ◽  
Magma Supply ◽  
Muon Radiography ◽  
Seismic Measurement ◽  
Measurement Campaigns ◽  
Better Than

Cosmic-ray muon radiography (muography), an imaging technique that can provide measurements of rock densities within the top few 100 m of a volcanic cone, has now achieved a spatial resolution of the order of 10 m in optimal detection conditions. Muography provides images of the top region of a volcano edifice with a resolution that is considerably better than that typically achieved with other conventional methods (i.e. gravimetric). We expect such precise measurements, to provide us with information on anomalies in the rock density distribution, which can be affected by dense lava conduits, low-density magma supply paths or the compression with the depth of the overlying soil. The MUon RAdiography of VESuvius (MURAVES) project is now in its final phase of construction and deployment. Up to four muon hodoscopes, each with a surface of roughly 1 m 2 , will be installed on the slope of Vesuvius and take data for at least 12 months. We will use the muographic profiles, combined with data from gravimetric and seismic measurement campaigns, to determine the stratigraphy of the lava plug at the bottom of the Vesuvius crater, in order to infer potential eruption pathways. While the MURAVES project unfolds, others are using emulsion detectors on Stromboli to study the lava conduits at the top of the volcano. These measurements are ongoing: they have completed two measurement campaigns and are now performing the first data analysis. This article is part of the Theo Murphy meeting issue ‘Cosmic-ray muography’.

Cosmic ray north-south anisotropy: The role of the interplanetary magnetic field

1982 ◽  
Vol 87 (A12) ◽  
pp. 10325 ◽  
Author(s):  
M. A. Pomerantz ◽  
S. P. Duggal ◽  
A. J. Owens ◽  
M. F. Tolba ◽  
C. H. Tsao
Keyword(s):  
Magnetic Field ◽  
Interplanetary Magnetic Field ◽  
Cosmic Ray

Cosmic‐Ray Production and the Role of Supernovae in NGC 6946

2001 ◽  
Vol 560 (2) ◽  
pp. 719-729 ◽  
Author(s):  
C. K. Lacey ◽  
N. Duric
Keyword(s):  
Cosmic Ray ◽  
Ngc 6946

scholarly journals Formation of large NAT particles and denitrification in polar stratosphere: possible role of cosmic rays and effect of solar activity

2004 ◽  
Vol 4 (1) ◽  
pp. 1037-1062 ◽  
Author(s):  
F. Yu
Keyword(s):  
Cosmic Rays ◽  
Strong Support ◽  
Ice Cores ◽  
Cosmic Ray ◽  
High Energy ◽  
Solar Proton ◽  
Arctic Regions ◽  
Secondary Ions ◽  
Selective Formation

Abstract. The formation of large nitric acid trihydrate (NAT) particles has important implications for denitrification and ozone depletion. Existing theories can't explain the recent observations of large NAT particles over wide Arctic regions at temperature above ice frost point. Our analyses reveal that high-energy comic rays may induce the freezing of supercooled HNO3−H2O–H2SO4 droplets when they penetrate these thermodynamically unstable droplets. The cosmic ray-induced freezing (CRIF) is consistent with the observed highly selective formation of NAT particles. We suggest that the physics behind the CRIF mechanism is the reorientation of polar solution molecules into the crystalline configuration in the strong electrical fields of moving secondary ions generated by passing cosmic rays. Our simulations indicate that strong solar proton events (SPEs) may significantly enhance the formation of large NAT particles and denitrification. The CRIF mechanism can explain the high correlations between the thin nitrate-rich layers in polar ice cores and major SPEs. The observed enhancement in aerosol backscattering ratio at PSC layers shortly after an SPE and the significant precipitation velocity of the enhanced PSC payers also provide strong support for the CRIF mechanism.

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