arXiv subjects

R. E. Lingenfelter

Publications and source records attributed to R. E. Lingenfelter.

21 records · Page 2Linked to original sources

arXiv1996

Light Elements and Cosmic Rays in the Early Galaxy

We derive constraints on the cosmic rays responsible for the Be and part of the B observed in stars formed in the early Galaxy: the cosmic rays cannot be accelerated from the ISM; their energy spectrum must be relatively hard (the bulk of the nuclear reactions should occur at $>$30 MeV/nucl); and only 10$^{49}$ erg/SNII in high metallicity, accelerated particle kinetic energy could suffice to produce the Be and B. The reverse SNII shock could accelerate the particles.

astro-ph↗

arXiv1996

LiBeB: High and low energy cosmic ray production and comparison with neutrino induced nucleosynthesis in SNII

We present new calculations of LiBeB production by accelerated particles with various compositions and energy spectra ranging from low energies to relativistic energies, and various ambient medium metallicities ($Z/Z_\odot$). The observed, essentially constant, Be/Fe ratio as a function of $Z/Z_\odot$ can be best understood if the metallicity of the accelerated particles (high energy or low energy) does not vary much with $Z/Z_\odot$. This could be achieved if the particles are accelerated directly from the ejecta of Type II supernovae (SNII) and not from the interstellar medium. Using the observed Be/Fe and the fact that most of the Fe at low $Z/Z_\odot$ is from SNII, we derive the energy content in accelerated particles per SNII (a few times 10$^{50}$ erg). We show that additional $^{11}$B production by neutrinos is consistent with the available data, allowing a neutrino yield from SNII less than or equal to the nominal published yields. We further show that the observed $^6$Li at low $Z/Z_\odot$ suggests that the accelerated particles responsible for the LiBeB at such $Z/Z_\odot$ are confined to low energies and have a relatively high He/O abundance.

astro-ph↗

arXiv1995

Astrophysical Gamma Ray Emission Lines

We review the wide range of astrophysical observations of gamma ray emission lines and we discuss their implications. We consider line emission from solar flares, the Orion molecular cloud complex, supernovae 1987A and 1991T, the supernova remnants Cas A and Vela, the interstellar medium, the Galactic center region and several Galactic black hole candidates. The observations have important, and often unique, implications on particle acceleration, star formation, processes of nucleosynthesis, Galactic evolution and compact object physics.

astro-ph↗