Variability of the flux densities of radio sources on timescales shorter than a month

Gorshkov, A. G.; Konnikova, V. K.; Мингалиев, М. Г.

doi:10.1134/s1063772910100045

Cited by 16 publications

(8 citation statements)

References 14 publications

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“…Thus repeated scanning of the same sky strip in the surveys not only increases the number of objects, but also makes it possible to study fainter sources compared to the mode described by Gorshkov et al [13].…”

Section: Deep Surveys On Ratan-600mentioning

confidence: 99%

“…The results of these long-term studies were reported in many publications by the researchers from the Sternberg Astronomical Institute, the Special Astrophysical Observatory of the Russian Academy of Sciences, and the Astro Space Center of the Lebedev Physical Institute of the Russian Academy of Sciences, e.g. [7][8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

“…This reduces the errors due to the repositioning of the antenna, which is especially important for the determination of flux densities of faint sources. Studies of variable sources carried out in the mode described by Gorshkov et al [13] involve repeated repositioning of the antenna to different areas of the sky.…”

Section: Deep Surveys On Ratan-600mentioning

confidence: 99%

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

Majorova

Желенкова

2012

Astrophys. Bull.

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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.

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Section: Deep Surveys On Ratan-600mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Majorova

Желенкова

2012

Astrophys. Bull.

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“…In particular, we estimate the coefficients V R [11] and V F [33], and the long-term variability index V [10] for each object of our sample.…”

Section: Revealing Variable Objects Among the Sourcesmentioning

confidence: 99%

Search for variable sources using data of “Cold” surveys

Majorova

Желенкова

2013

Astrophys. Bull.

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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.

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“…According to Hughes, Aller, and Aller (1992), the time scale of an AGN flare is two years, on average. The Intra-day Variability (IDV), a flux variability of AGN with a time scale of about one day, is also known (Quirrenbach et al 1992;Gorshkov et al 2010). This very fast variability is, however, probably caused by interstellar scintillation (Jauncey et al 2000), and not an intrinsic one.…”

Section: Introductionmentioning

confidence: 99%

An Intrinsic Short-Term Radio Variability Observed in PKS 1510−089

Kadota¹,

Fujisawa

Sawada-Satoh

et al. 2012

Publications of the Astronomical Society of Japan

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We searched a short-term radio variability in an active galactic nucleus, PKS 1510 089. Daily flux monitoring for 143 d at 8.4 GHz was performed, and VLBI observations at 8.4, 22, and 43 GHz were carried out 4 times during the flux monitoring period. As a result, variability with a time scale of 20 to 30 d was detected. The variation patterns were very much alike at three frequencies; moreover, those at 22 and 43 GHz were synchronized. These properties support that this short-term variability is an intrinsic one. The Doppler factor estimated from the variability time scale is 47. Since the Doppler factor is not extraordinary large for AGN, such intrinsic variability with a time scale of less than 30 d would exist in other AGNs.

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Variability of the flux densities of radio sources on timescales shorter than a month

Cited by 16 publications

References 14 publications

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

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

Search for variable sources using data of “Cold” surveys

An Intrinsic Short-Term Radio Variability Observed in PKS 1510−089

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