Spectral characteristics of radio sources near the North Celestial Pole

Мингалиев, М. Г.; Sotnikova, Yu. V.; Бурсов, Н. Н.; Кардашев, Н. С.; Ларионов, М. Г.

doi:10.1134/s1063772907050010

Cited by 17 publications

(18 citation statements)

References 10 publications

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“…The data were processed using an automated system of the reduction developed for the RATAN-600 continuum observations [48], based on the modules of the standard FADPS (Flexible Astronomical Data Processing System) package [49] and designed for a mass interactive processing of output of the RATAN data. Estimates of measurement errors and the flux density calibration procedure can be found in [12,13,48,[50][51][52]. The information for secondary calibration standards is taken from [53][54][55][56].…”

Section: The Sample Properties and Observationsmentioning

confidence: 99%

Multifrequency Study of GHz-peaked Spectrum Sources

et al. 2019

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Gigahertz-Peaked spectrum (GPS) sources are compact active galactic nuclei, presumably young precursors of bright radio sources. The study of GPS radio properties provides information about the features of synchrotron radiation in extragalactic sources. Also in applied research GPS sources are useful as compact stationary radio sources in the sky for astrometric purposes. This paper presents the results of a multifrequency GPS study based on quasi-simultaneous measurements with the RATAN-600 radio telescope during the 2006-2017. The catalog containing spectral flux densities measured at six frequencies (1.1, 2.3, 4.8, 7.7/8.2, 11.2, and 21.7 GHz) have been obtained. In addition, for the analysis of radio spectra, data from the following low-frequency surveys have been used: GLEAM (GaLactic and Extragalactic All-sky Murchison widefield array survey) and TGSS (Tata institute for fundamental research GMRT Sky Survey) and high-frequency measurements from Planck survey. A total number of 164 GPS and candidates to GPS have been identified (17 of them are new discoveries), which makes up a small fraction of GPS in the initial sample of bright AGNs, about 2%. The physical properties and formation conditions of synchrotron radiation is found to be quite different in GPS of different AGN types. The deficit of distant GPS (z > 2) with low maximum frequencies (less than 1 GHz) is confirmed. The existing "size -peak frequency" anticorrelation is continuous. The continuum radio spectra are found to become statistically steeper with increasing redshift.

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Section: The Sample Properties and Observationsmentioning

confidence: 99%

Multifrequency Study of GHz-peaked Spectrum Sources

et al. 2019

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“…The accuracy of the antenna temperature of each source was determined as the standard error of the mean from N observations of a set, taking into account the Student factor. Details on observation and analysis technique are given by Mingaliev et al (2001Mingaliev et al ( , 2007. The errors of the antenna temperature depend not only on the receiver noise, but also on the atmospheric fluctuations on the scale of the main beam, on the accuracy of antenna surface setting for the actual source observation and on the accuracy of the feed cabin positioning (the cabin with secondary mirror and receivers).…”

Section: Sample and Observationsmentioning

confidence: 99%

Multifrequency study of GHz-peaked spectrum sources and candidates with the RATAN-600 radio telescope

Мингалиев

Sotnikova

Torniainen

et al. 2012

A&A

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Context. Gigahertz peaked spectrum (GPS) radio sources are a class of extragalactic radio sources characterized by a spectral peak in the gigahertz domain. They are a mixed class of quasars and galaxies. A large proportion of the sources studied in the literature have only few data points in the radio domain, and the determination of variability and shape of the simultaneous spectra is inadequate. Sources currently included in the GPS source lists are very heterogeneous. Aims. We present the observational results from 12 observing campaigns (carried out between 2006 and 2010) at the RATAN-600 radio telescope to obtain the simultaneous radio spectra, which is valuable and necessary to derive genuine GPS sources from flatspectrum radio sources caught in a flaring state when their spectra are temporarily inverted. The sample contains both quasar-and galaxy-type GPS (122 sources) identified in the literature. Methods. The observations were carried out at six frequencies (1.1, 2.3, 4.8, 7.7, 11.2 and 21.7 GHz). The flux densities were measured at several epochs. A six-frequency broadband radio spectrum was obtained by observing simultaneously with an accuracy of up to a minute at 1.4, 2.7, 3.9, 6.25, 13, and 30 cm. Results. The original GPS source samples were highly contaminated. Finally, we selected 29% GPS source candidates within the sample. We found some difference in spectral properties between GPS galaxies and quasars within the sample. The GPS galaxies demonstrate a steeper spectral index in the optically thin part of the spectra. There are only relatively few (17) sources whose radio spectra strictly agree with the spectra of homogeneous self-absorbed synchrotron sources. The narrowest radio spectra are found in both ultra-high-z (z ≥ 1.8) and low-z (0.02 ≤ z ≤ 0.7, FWHM ∼ 0.9) convex spectrum radio sources. The majority of quasars within this sample should be considered as flat-spectrum radio sources with a temporarily inverted spectrum, and not as genuine GPS sources. The number of truly convex-spectrum sources remains low, and the lists of GPS sources should accordingly be revised.

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“…In order to construct an accurate template for masking out the point sources in the C-BASS maps, it is necessary to construct a pointsource catalogue based on the C-BASS observations themselves and any useful information that can be gleaned from other more sensitive, higher resolution surveys. Relevant to our work in this paper are the GB6 (Gregory et al 1996), PMN (Griffith & Wright 1993;Griffith et al 1994Griffith et al , 1995Wright et al 1994Wright et al , 1996a, Effelsberg S5 (Kuehr et al 1981), RATAN-600 (Mingaliev et al 2007), and Combined Radio All-Sky Targeted Eight-GHz Survey (CRATES; Healey et al 2007) catalogues. These catalogues are primarily used in this paper to make comparisons with the C-BASS catalogue, for the purposes of data validation and estimation of the statistical properties of the C-BASS catalogue.…”

Section: P R E -E X I S T I N G S O U R C E C Ata L O G U E Smentioning

confidence: 99%

“…In comparing to the S5 catalogue, there are significant issues from the variability of flat-spectrum sources, given the large separation in time between the S5 survey and the C-BASS survey. The RATAN-600 catalogue includes measurements at 4.8 GHz, and observed 504 sources in the NCP region with NRAO VLA Sky Survey (NVSS) flux-densities, S 1.4 GHz ≥ 200mJy (Mingaliev et al 2001(Mingaliev et al , 2007. The RATAN-600 catalogue was used in a previous analysis of diffuse emission in the NCP region with C-BASS in Dickinson et al (2019).…”

Section: P R E -E X I S T I N G S O U R C E C Ata L O G U E Smentioning

confidence: 99%

The C-Band All-Sky Survey: total intensity point-source detection over the northern sky

Grumitt

Taylor

Jew

et al. 2020

Monthly Notices of the Royal Astronomical Society

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ABSTRACT We present a point-source detection algorithm that employs the second-order Spherical Mexican Hat wavelet filter (SMHW2), and use it on C-Band All-Sky Survey (C-BASS) northern intensity data to produce a catalogue of point sources. This catalogue allows us to cross-check the C-BASS flux-density scale against existing source surveys, and provides the basis for a source mask that will be used in subsequent C-BASS and cosmic microwave background (CMB) analyses. The SMHW2 allows us to filter the entire sky at once, avoiding complications from edge effects arising when filtering small sky patches. The algorithm is validated against a set of Monte Carlo simulations, consisting of diffuse emission, instrumental noise, and various point-source populations. The simulated source populations are successfully recovered. The SMHW2 detection algorithm is used to produce a $4.76\, \mathrm{GHz}$ northern sky source catalogue in total intensity, containing 1784 sources and covering declinations δ ≥ −10°. The C-BASS catalogue is matched with the Green Bank 6 cm (GB6) and Parkes-MIT-NRAO (PMN) catalogues over their areas of common sky coverage. From this we estimate the 90 per cent completeness level to be approximately $610\, \mathrm{mJy}$, with a corresponding reliability of 98 per cent, when masking the brightest 30 per cent of the diffuse emission in the C-BASS northern sky map. We find the C-BASS and GB6 flux-density scales to be consistent with one another to within approximately 4 per cent.

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Spectral characteristics of radio sources near the North Celestial Pole

Cited by 17 publications

References 10 publications

Multifrequency Study of GHz-peaked Spectrum Sources

Multifrequency Study of GHz-peaked Spectrum Sources

Multifrequency study of GHz-peaked spectrum sources and candidates with the RATAN-600 radio telescope

The C-Band All-Sky Survey: total intensity point-source detection over the northern sky

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