Investigation of characteristics of radio telescopes by methods of coherent optics and holography

Бурсов

2007

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 λ7.6 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 [1].

Section: Introductionmentioning

confidence: 99%

Study of the power beam pattern of RATAN-600 during the deep RZF survey (1998–2003)

Бурсов

2007

“…Let us recall some of the features of the observations on the RATAN-600 radio telescope whose PBP differs significantly from that of a parabolic dish [28][29][30][31][32]. In the mode of single-sector observations the PBP broadens with increasing angu- We repeated the reduction of the selected sources.…”

Section: Construction Of the Calibrating Curves And Estimation Of Thementioning

confidence: 99%

On possibility of detection of variable sources using the data of “Cold” surveys carried out on RATAN-600

Желенкова

2012

In this study we attempt to assess the possibility of detection of variable sources using the data of the 7.6-cm wavelength surveys carried out on the RATAN-600 radio telescope in the period from 1980 through 1994. Objects selected according to certain criteria from the RCR catalog are used to construct the calibration curves and to estimate the accuracy of the resulting calibration curves and determine the r.m.s. errors for the measured source flux densities. To check the calibration sources for the presence of variable objects, quantitative estimates are performed for a number of parameters that characterize variability, in particular, for the long-term variability index V and the χ 2 (chi-square) probability p. The long-term variability index was found to be positive for 14 out of approximately 80 calibration sources, possibly indicating that these sources are variable. The most likely candidate variables are the three sources with the χ 2 probability p > 0.95. Five sources have χ 2 probabilities in the 0.85 < p < 0.95 interval, and the remaining six in the 0.6 < p < 0.8 interval.Nine out of 14 objects are possibly variable in the optical range. The light curves and spectra are determined for possible variable sources and a number of "non-variable" objects. We plan to use the results of this study in our future searches for variable radio sources using the data of the "Cold" surveys.

“…This reduces the errors due to the realignment of the antenna, and this is especially important for the determination of flux densities of sufficiently faint sources. single-sector observations [24][25][26][27][28], a large number of sources are found simultaneously within its field of view. Thus at 7.6 cm more than 30000 NVSS objects [29] pass within the field of view in a single crossing of the sky.…”

Section: Use Of Surveys To Search For Variable Sourcesmentioning

confidence: 99%

Search for variable sources using data of “Cold” surveys

Желенкова

2013

We search for variable sources, using the data of the surveys conducted on the RATAN-600 radio telescope in 1980-1994 at 3.94 GHz. To test the radio sources of the RCR (RATAN Cold Refined) catalog for variability, we estimated the long-term variability indices V of the studied objects, their relative variability amplitudes V χ , and the χ 2 probabilities p. Out of about two hundred considered sources, 41 proved to have positive long-term variability indices, suggesting that these sources may be variable. Fifteen objects can be considered to be reliably variable according to the χ 2 criterion p > 0.98, three of these sources have χ 2 probabilities p ≥ 0.999. The corresponding probabilities for six sources lie in the 0.95 < p < 0.98 interval, and those of the remaining 20 objects in the 0.73 ≤ p < 0.95 interval. Twenty-four of 41 objects are variable or possibly variable in the optical range, and five objects are known variable radio sources. We construct the light curves and spectra for the sources with positive long-term variability indices.