58 research outputs found
The KHOLOD Experiment: A Search for a New Population of Radio Sources
Published data from long-term observations of a strip of sky at declination
+5 degrees carried out at 7.6 cm on the RATAN-600 radio telescope are used to
estimate some statistical properties of radio sources. Limits on the
sensitivity of the survey due to noise imposed by background sources, which
dominates the radiometer sensitivity, are refined. The vast majority of noise
due to background sources is associated with known radio sources (for example,
from the NVSS with a detection threshold of 2.3 mJy) with normal steep spectra
({\alpha} = 0.7-0.8, S \propto {\nu}^{- \alpha}), which have also been detected
in new deep surveys at decimeter wavelengths. When all such objects are removed
from the observational data, this leaves another noise component that is
observed to be roughly identical in independent groups of observations. We
suggest this represents a new population of radio sources that are not present
in known catalogs at the 0.6 mJy level at 7.6 cm. The studied redshift
dependence of the number of steep-spectrum objects shows that the sensitivity
of our survey is sufficient to detect powerful FRII radio sources at any
redshift, right to the epoch of formation of the first galaxies. The inferred
new population is most likely associated with low-luminosity objects at
redshifts z < 1. In spite of the appearance of new means of carrying out direct
studies of distant galaxies, searches for objects with very high redshifts
among steep and ultra-steep spectrum radio sources remains an effective method
for studying the early Universe.Comment: 13 pages, 10 figure
Study of the Cygnus X-3 Microquasar with the RATAN-600 Radio telescope in Multi-Azimuth Observing Mode
We have been performing daily observations of bright microquasars at
1.2-20~GHz with the Northern sector of RATAN-600 radio telescope for more than
ten years. During the 2019--2021 observations we recorded bright flares, which
we call giant flares because fluxes reach record levels -- above 20~Jy --
during these events. In this paper we report the results of intraday variations
of the Cygnus~X-3} microquasar in multi-azimuth observations made with the
"North sector with a flat-sheet reflector" during giant flares of Cygnus X-3.
These were the first such observations made simultaneously at several
frequencies on a short time scale (10 minutes). Observational data consists of
31 measurement made within +/-2.7 hours of the culmination of the object. We
are the first to discover the evolution of the spectrum of the flare emission
of Cygnus~X-3 on a time scale comparable to the orbital period of the binary.
The measurement data allowed us to determine the temporal and spectral
parameters of radio emission, which are typical for synchrotron flare emission
in relativistic jets. Evolution of the radio emission of X-ray binaries on
short time scales is a key to understanding the formation of jet outbursts in
the process of mass accretion of the matter of the donor star onto the
relativistic object.Comment: 10 pages, 13 figures, 2 tables, maik.st
Study of the Power Beam Pattern of RATAN-600 During the Deep RZF Survey (1998-2003)
This paper proposes a method for constructing an experimental power beam
pattern (PB) of RATAN-600 based on the sample of NVSS sources observed in the
process of a deep sky survey near local zenith. The data obtained from
observations of radio sources at wave 7.6 cm in nine bands of the survey (the
2002 and 2003 sets) are used to construct vertical PB of the telescope at
rather large offsets from the central horizontal section of the PB (+/-36').
The experimental PBs obtained using different methods are compared and the
root-mean-square deviations of the experimental PB from the corresponding
computed PB are determined. The stability of the power beam pattern in its
central part (+/-6') during the RATAN-600 Zenith Field (RZF) survey (1998-2003)
and the accuracies of the fluxes of the sources observed within the framework
of this survey and included into the RZF catalog are estimated.Comment: 15 pages, 17 figure
The results of monitoring of the SETI-objects at RATAN-600 in 2015—2016
В настоящей работе исследованы SETI-объекты, наблюдавшиеся на РАТАН-600 в цикле наблюдений 2015 2016 гг. 30 объектов (28 солнцеподобных звезд и 2 шаровых скопления с высокой металличностью) наблюдались на широкополосном 3-частотном приемном комплексе с высокой чувствительностью на южном секторе радиотелескопа.In the present work SETI-objects observed on radiotelescope RATAN-600 were investigated. Observations were carried out in 2015—2016 on a broadband 3-frequency receiving system with a high sensitivity in the southern sector of the radio telescope. The objects of observations are 28 sunlike stars and 2 globular clusters with high metallicity
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