9,168 research outputs found
Recent extensions to GALPROP
Some recent extensions to the GALPROP cosmic-ray propagation package are
described. The enhancements include: an accurate solution option, improved
convection formulation, alternative spatial boundary conditions, polarized
synchrotron emission, new magnetic field models, updated gamma-ray production
cross-sections, free-free radio emission and absorption, primary positrons,
additional injection spectral breaks, deuterium production by pp fusion,
hadronic energy losses, improved HEALPix skymap format, compatibility with
latest HEALPix release, and various bug fixes. The Explanatory Supplement has
been extensively updated, including details of these enhancements. A compatible
plot package GALPLOT for GALPROP output is also provided, as well as other
related software.Comment: Contribution to the 34th International Cosmic Ray Conference, July 30
to August 6, The Hague, Netherland
Interstellar gamma rays and cosmic rays: new insights from Fermi-LAT AND INTEGRAL
In over two years of operation Fermi-LAT has revolutionized our knowledge of
the gamma-ray sky. Interstellar gamma rays are part of this new era and allow
unprecedented tests for models of cosmic rays in the Galaxy. The extension to
lower energies with INTEGRAL/SPI data is also evolving. The global
multiwavelength luminosity of the Milky Way has been derived, with implications
for the Galactic energy balance and the radio-FIR correlation.Comment: Accepted for publication in the Proceedings of the ICATPP Conference
on Cosmic Rays for Particle and Astroparticle Physics, Villa Olmo (Como,
Italy), 7-8 October, 2010, to be published by World Scientific (Singapore
Local interstellar cosmic-ray spectra derived from gamma-ray emissivities
Precise gamma-ray emissivities from cosmic-ray interactions with interstellar
gas have been recently derived using Fermi-LAT data, and used to constrain the
local interstellar spectra of protons and leptons. We report on a continuing
effort to exploit these emissivities combined with the latest hadronic
gamma-ray production cross-sections and other constraints such as synchrotron
emission for the leptonic component. The interstellar spectra provide important
information for heliospheric modulation, and cosmic-ray origin and propagation.Comment: Contribution to the 34th International Cosmic Ray Conference, July 30
to August 6, The Hague, Netherland
Local electron spectrum above 100 MeV derived from gamma-ray emissivity spectra
Two new determinations of the local gamma-ray emmissivity spectrum are in good accord and were used to derive constraints on the local electron spectrum. The requirement for an electron intensity above 1 GeV larger than previously believed is confirmed and no low energy upturn is then needed
Modelling cosmic rays and gamma rays in the Galaxy
An extensive program for the calculation of galactic cosmic-ray propagation
has been developed. This is a continuation of the work described in Strong &
Youssefi (1995). The main motivation for developing this code is the prediction
of diffuse Galactic gamma rays for comparison with data from the CGRO
instruments EGRET, COMPTEL, and OSSE. The basic spatial propagation mechanisms
are (momentum-dependent) diffusion, convection, while in momentum space energy
loss and diffusive reacceleration are treated. Primary and secondary nucleons,
primary and secondary electrons, and secondary positrons are included.
Fragmentation and energy losses are computed using realistic distributions for
the interstellar gas and radiation fields.
This study indicates that it is possible to construct a model satisfying a
wide range of observational constraints and provides a basis for future
developments.Comment: 5 pages including 7 figures, latex, aipproc.sty, aipproc.cls,
epsfig.sty. To be published in Proc. 4th Compton Symp., 1997 (27-30 April,
Williamsburg, Virginia). Details can be found at
http://www.gamma.mpe-garching.mpg.de/~aws/aws.htm
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