520 research outputs found
âSOFT POWERâ, COMMUNICATION AND THE PROBLEM OF HUMANITARIAN CRISIS
The article is devoted to the philosophical inquiry of the worldview connection between soft power, information and humanitarian crisis of modernity. The purpose of the work is the integrative philosophical analysis of the expression of the âsoft powerâ and informational technologies in the modern social context. It has been concluded that the main negative aspect of âsoft powerâ influence is depreciation of human personality as the last value of the informational society. The way out can be found in transformation of the systems and sub-systems of social communication. Key words: Knowledge, Soft Power, Influence, Information, Society. Â Â
The origin of the 6.4 keV line emission and H ionization in the diffuse molecular gas of the Galactic center region
We investigate the origin of the diffuse 6.4 keV line emission recently
detected by Suzaku and the source of H_2ionization in the diffuse molecular gas
of the Galactic Center (GC) region. We show that Fe atoms and H_2 molecules in
the diffuse interstellar medium of the GC are not ionized by the same
particles. The Fe atoms are most likely ionized by X-ray photons emitted by Sgr
A* during a previous period of flaring activity of the supermassive black hole.
The measured longitudinal intensity distribution of the diffuse 6.4 keV line
emission is best explained if the past activity of Sgr A$* lasted at least
several hundred years and released a mean 2-100 keV luminosity > 10^38} erg
s^{-1}. The H_2 molecules of the diffuse gas can not be ionized by photons from
Sgr A*, because soft photons are strongly absorbed in the interstellar gas
around the central black hole. The molecular hydrogen in the GC region is most
likely ionized by low-energy cosmic rays, probably protons rather than
electrons, whose contribution into the diffuse 6.4 keV line emission is
negligible.Comment: 5 pages, 4 figues, accepted for publication in the Astrophysical
Journal Letter
Gamma-Ray Emission from Molecular Clouds Generated by Penetrating Cosmic Rays
We analyze the processes governing cosmic-ray (CR) penetration into molecular
clouds and the resulting generation of gamma-ray emission. The density of CRs
inside a cloud is depleted at lower energies due to the self-excited MHD
turbulence. The depletion depends on the effective gas column density ("size")
of the cloud. We consider two different environments where the depletion effect
is expected to be observed. For the Central Molecular Zone, the expected range
of CR energy depletion is GeV, leading to the depletion of
gamma-ray flux below GeV. This effect can be important for
the interpretation of the GeV gamma-ray excess in the Galactic Center, which
has been revealed from the standard model of CR propagation (assuming the CR
spectrum inside a cloud to be equal to the interstellar spectrum). Furthermore,
recent observations of some local molecular clouds suggest the depletion of the
gamma-ray emission, indicating possible self-modulation of the penetrating
low-energy CRs.Comment: 10 pages, 5 figures, accepted for publication in Ap
Multi-wavelength Emission from the Fermi Bubble III. Stochastic (Fermi) Re-Acceleration of Relativistic Electrons Emitted by SNRs
We analyse the model of stochastic re-acceleration of electrons, which are
emitted by supernova remnants (SNRs) in the Galactic Disk and propagate then
into the Galactic halo, in order to explain the origin on nonthermal (radio and
gamma-ray) emission from the Fermi Bubbles (FB). We assume that the energy for
re-acceleration in the halo is supplied by shocks generated by processes of
star accretion onto the central black hole. Numerical simulations show that
regions with strong turbulence (places for electron re-acceleration) are
located high up in the Galactic Halo about several kpc above the disk. The
energy of SNR electrons that reach these regions does not exceed several GeV
because of synchrotron and inverse Compton energy losses. At appropriate
parameters of re-acceleration these electrons can be re-accelerated up to the
energy 10E12 eV which explains in this model the origin of the observed radio
and gamma-ray emission from the FB. However although the model gamma-ray
spectrum is consistent with the Fermi results, the model radio spectrum is
steeper than the observed by WMAP and Planck. If adiabatic losses due to plasma
outflow from the Galactic central regions are taken into account, then the
re-acceleration model nicely reproduces the Planck datapoints.Comment: 33 pages, 8 figures, accepted by Ap
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