215 research outputs found
Current status of cosmological MDM model
An analysis of cosmological models in spatially flat Friedmann Universe with
cosmic gravitational wave background and zero -term is presented. The
number of free parameters is equal to 5, they are , ,
, , and . The normalization of the spectrum of density
perturbations on galaxy cluster abundance () has been
used to calculate numerically the value of the large scale CMB anisotropy
() and the relative contribution of cosmological gravitational
waves T/S. Increasing weaken the requirements to the value of T/S,
however even for the models with suggest
considerable abundance of gravitational waves: T/S. In models
with and scale-invariant spectrum of density perturbations
(): T/S. Minimization of the value T/S is possible
only in the range of the red spectra () and small (). It is
shown that the models with T/S admit both moderate red and blue
spectra of density perturbations, , with rather high abundance
hot dark matter, . Any condition, or
, decreases the relative amplitude of the first acoustic peak
for more than 30% in comparison with its hight in the standard CDM normalized
by COBE data.Comment: 4 pages, 2 figures included; contribution to the Proceedings of
Moriond 2000 "Energy Densities in the Universe", Les Arcs, France, January
22-29 200
Prospects for observing supermassive black hole binaries with the space-ground interferometer
A list of candidates for \textit{supermassive binary black holes} (SMBBHs),
compiled from available data on the variability in the optical range and the
shape of the emission spectrum, is analysed. An artificial neural network is
constructed to estimate the radiation flux at 240~GHz. For those candidate
SMBBH for which the network building procedure was feasible, the criterion of
the possibility of observing the source at the \textit{Millimetron Space
Observatory} (MSO) was tested. The result is presented as a table of 17
candidate SMBBHs. Confirmation (or refutation) of the duality of these objects
by means of observational data which could be commited on a space-ground
interferometer with parameters similar to those of the MSO will be an important
milestone in the development of the theory of galaxy formation.Comment: 15 pages, 6 figures, 2 table, accepted for publication in Astronomy
Report
Spectral Survey of the Star Formation Region DR21OH in the 4 mm Wavelength Range
The results of a spectral survey of the region of massive star formation
DR21OH in the 4-mm wavelength range are presented. Sixty-nine molecules and
their isotopologues have been detected, ranging from simple diatomic or
triatomic species such as SO, SiO and CCH, to complex organic molecules such as
CHOCHO or CHOCH. The obtained results qualitatively repeat the
results of the survey of the same source at 3~mm. The inventories of molecules
found at 3mm and 4mm overlap to a great extent. However, at 4 mm we found a
number of species that have no allowed transitions in the 3-mm wavelength
range, e.g. DCN, DNC, or SO. The bulk of the molecules detected at 4~mm are
those that are common for dense cores, e.g., HCN or CHCCH, but some of
the detected species are typical for hot cores. The latter include complex
organic molecules CHOCHO, CHCHOH, CHOCH, etc. However, the
detected emission of these molecules probably arises in a gas heated to 30 K
only. Nine molecules, including complex species CHCN, CHCHCN,
CHCOCH, were found by spectral line stacking. This demonstrates the
prospects of the method in the study of molecular clouds.Comment: 36 pages, 4 figure
- …