36 research outputs found
Familon Model of Dark Matter
If the next fundamental level of matter occurs (preons) then dark matter must
consist of familons containing a "hot" component from massless particles and a
"cold" component from massive particles. During evolution of the Universe this
dark matter was undergone to late-time relativistic phase transitions
temperatures of which were different. Fluctuations created by these phase
transitions have had a fractal character. In the result the structurization of
dark matter (and therefore the baryon subsystem) has taken place and in the
Universe some characteristic scales which have printed this phenomenon arise
naturally. Familons are collective excitations of nonperturbative preon
condensates which could be produced during more early relativistic phase
transition. For structurization of dark matter (and baryon component) three
generations of particles are necessary. The first generation of particles has
produced the observed baryon world. The second and third generations have
produced dark matter from particles which have appeared when symmetry among
generations was spontaneously broken.Comment: 12 page
Cosmology of Vacuum
Shortly the vacuum component of the Universe from the geometry point of view
and from the point of view of the standard model of physics of elementary
particles is discussed. Some arguments are given to the calculated value of the
cosmological constant (Zeldovich approximation). A new component of space
vacuum (the gravitational vacuum condensate) is involved the production of
which has fixed time in our Universe. Also the phenomenon of vacuum
selforganization must be included in physical consideration of the Universe
evolution.Comment: 8 page
The Effect of 53 micron IR Radiation on 18 cm OH Megamaser Emission
OH megamasers (OHMs) emit primarily in the main lines at 1667 and 1665 MHz,
and differ from their Galactic counterparts due to their immense luminosities,
large linewidths and 1667/1665 MHz flux ratios, which are always greater than
one. We find that these maser properties result from strong 53 micron radiative
pumping combined with line overlap effects caused by turbulent linewidths of
about 20 km/s; pumping calculations that do not include line overlap are
unreliable. A minimum dust temperature of about 45 K is needed for inversion,
and maximum maser efficiency occurs for dust temperatures in the range 80 - 140
K. We find that warmer dust can support inversion at lower IR luminosities, in
agreement with observations. Our results are in good agreement with a clumpy
model of OHMs, with clouds sizes about 1 pc and OH column densities about 5e16
cm^2, that is able to explain both the diffuse and compact emission observed
for OHMs. We suggest that all OH main line masers may be pumped by far-IR
radiation, with the major differences between OHMs and Galactic OH masers
caused by differences in linewidth produced by line overlap. Small Galactic
maser linewidths tend to produce stronger 1665 MHz emission. The large OHM
linewidths lead to inverted ground state transitions having approximately the
same excitation temperature, producing 1667/1665 MHz flux ratios greater than
one and weak satellite line emission. Finally, the small observed ratio of
pumping radiation to dense molecular gas, as traced by HCN and HCO, is a
possible reason for the lack of OH megamaser emission in NGC 6240.Comment: Accepted to ApJ, 26 pages including 1 table and 7 figure