2,604 research outputs found
TeV neutrinos from microquasars in compact massive binaries
We consider a compact binary system in which a Wolf-Rayet star supplies
matter onto a stellar mass black hole or a neutron star. This matter forms an
accretion disk which ejects a jet as observed in Galactic microquasars. A part
of the jet kinetic energy, typically 10%, can be transfered to relativistic
nuclei. These nuclei lose nucleons as a result of photo-disintegration process
in collisions with thermal photons from the accretion disk and the massive
star. Due to the head on photon-nucleus collisions most of neutrons released
from nuclei move towards the surface of the accretion disk and/or the massive
star producing neutrinos in collisions with the matter. We calculate the
spectra of muon neutrinos and expected neutrino event rates in a 1 km^2
neutrino detector of the IceCube type from a microquasar inside our Galaxy
applying, as an example, the parameters of the Cyg X-3 binary system, provided
that nuclei are accelerated to the Lorentz factors above 10^6 with the power
law spectrum with an index close to 2.Comment: 13 pages, 2 figures, ApJ, accepte
Geomagnetic field and altitude effects on the performance of future IACT arrays
The performance of IACT's arrays is sensitive to the altitude and geomagnetic
field (GF) of the observatory site. Both effects play important role in the
region of the sub-TeV gamma-ray measurements. We investigate the influence of
GF on detection rates and the energy thresholds for five possible locations of
the future CTA observatory using the Monte Carlo simulations. We conclude that
the detection rates of gamma rays and the energy thresholds of the arrays can
be fitted with linear functions of the altitude and the component of the GF
perpendicular to the shower axis core. These results can be directly
extrapolated for any possible localization of the CTA. In this paper we also
show the influence of both geophysical effects on the images of shower and
gamma/hadron separation.Comment: 4 pages, 6 figures, two-column. Contribution to ICRC 2013 proceeding
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