Performance Evaluation of Irbene RT-16 Radio Telescope Receiving System

Bleiders, M.; Bezrukovs, Vl.; Orbidans, A.

doi:10.1515/lpts-2017-0040

Cited by 12 publications

(3 citation statements)

References 1 publication

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“…It takes about 17 seconds to get one sample of flux density; every 7 samples are averaged to reduce noise. The technique of observations and study of parameters of radio telescopes are described in more detail in article [4].…”

Section: Methods Of Observationsmentioning

confidence: 99%

AGN intra-day and inter-day variability studies with VIRAC radio telescopes

Bezrukovs¹,

Sukharev²,

Ryabov³

et al. 2019

Proceedings of 14th European VLBI Network Symposium &Amp; Users Meeting — PoS(EVN2018)

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Since year 2017, radio telescopes of Ventspils International Radio Astronomy Centre (VIRAC) are used to study intra-day and inter-day variability of various types of active galactic nuclei (AGN). These studies are based on a generalization of the results of a 40-year monitoring of extragalactic radio sources flux conducted by Michigan Radio Astronomy Observatory in the USA using wavelet and Fourier analysis performed at Odessa Observatory of the Radio Astronomy Institute of the National Academy of Sciences (NAS) of Ukraine. On this basis, a catalogue for the properties of the variability of extragalactic radio sources was created. The extension of the temporal spectrum of flux changes to inter-diurnal and diurnal scales is carried out with the help of VIRAC radio telescopes RT-32 and RT-16 respectively with 32-and 16-meter antennas. The intra-day variability of the calibration source 3C295 (Type 2 Seyfert Galaxy) is detected and preliminary results presented in the paper for discussion. Several other radio sources (3C 273, 3C 454.3, OJ 287, BL Lac) are suspected to have variability of such type and are scheduled for monitoring observations as well. The paper discusses possibility of observing these promising objects during VLBI sessions by EVN and parallel long-term total flux monitoring with VIRAC antennas. The temporal changes in flux linked with VLBI maps opens opportunity to determine the nature of the physical processes that form fast flux changes of various types of active galactic nuclei.

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Section: Methods Of Observationsmentioning

confidence: 99%

AGN intra-day and inter-day variability studies with VIRAC radio telescopes

Bezrukovs¹,

Sukharev²,

Ryabov³

et al. 2019

Proceedings of 14th European VLBI Network Symposium &Amp; Users Meeting — PoS(EVN2018)

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“…A comparison of the G/T sys with some antennas in K-Band with the proposed system is given in TABLE III 23,24 . Also, FIG.…”

Section: G/t Sys Estimate Of the Systemmentioning

confidence: 99%

A High-Sensitivity Cryogenic Radio Receiver: Design, Performance and Polarization Analysis

Mohammadian,

McCulloch,

Gilles

et al. 2024

Preprint

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Large reflector antennas are subjected to testing for calibration accuracy and precision, ensuring signal reception sensitivity and consistent performance across an extended frequency range. In this paper, we introduce a cryogenic radio receiver which is placed on a 5.3 m reflector with a gain of 60.19 dB. This antenna serves as the reference antenna for holographic calibration measurements with the measured G/Tsys ~42 dB/K. The receiver provides a bandwidth of 2 GHz (21-23 GHz), the receiver's noise temperature is 19.55, and The polarization conversion yields an Axial Ratio (AR) of less than 1.3 dB.

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“…It is remotely controlled from the VIRAC office in Ventspils. More detailed information about the methodology for conducting observations and obtaining the flux density of radio sources in Janskys, as well as information about testing the radio telescope and studying its parameters, is presented in the work [5].…”

Section: Introductionmentioning

confidence: 99%

Program and Results of Investigations Rapid Variability of the BL Lac Object 3C 371 in Radio and Optical Ranges

et al. 2020

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BL Lac object 3C 371 is variable in optical and radio range, according to long-term monitoring data, for example AAVSO (American Association of Variable Star Observers) and OVRO (Owens Valley Radio Observatory). In addition, some authors note intra-night variability. However, in terms of access, just a few works are devoted to this topic, and questions remain about intra-day variability in radio range. The purpose of the work is to search for fast variability in radio (5, 6.1, 6.7 GHz) and optical bands (V, R, I) using international cooperation in 2019 and 2020 observation sessions. The 16-m radio telescope VIRAC, in Latvia, as well as optical telescopes AZT-3 (Mayaki, Ukraine), VNT (Vihorlat, Slovakia), and Schmidt camera (Baldone, Latvia) were used. To analyze variability, the STFT method of spectrograms and Lomb–Scargle periodograms for non-uniform time series were used. As result of the work, there is no correlation between optical and radio observations, and no significant quasi-harmonic variability was detected in radio range, but there is irregular low amplitude variability. In the optical range, there is variability with a characteristic time of about seven days and possibly less. Cyclical variability of 3C 371 was found in the optical range, and intra-day variability in radio range is most likely absent, as there are irregular variations and noise. It is planned to continue joint radio-optical observations 3C 371 to accumulate the necessary statistics.

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Performance Evaluation of Irbene RT-16 Radio Telescope Receiving System

Cited by 12 publications

References 1 publication

AGN intra-day and inter-day variability studies with VIRAC radio telescopes

AGN intra-day and inter-day variability studies with VIRAC radio telescopes

A High-Sensitivity Cryogenic Radio Receiver: Design, Performance and Polarization Analysis

Program and Results of Investigations Rapid Variability of the BL Lac Object 3C 371 in Radio and Optical Ranges

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