The 5 GHz strong source surveys. IV - Survey of the area between declination 35 and 70 degrees and summary of source counts, spectra and optical identifications

Pauliny-Toth, I. I. K.; Witzel, A.; Preuss, E.; Kuehr, H.; Fomalont, E. B.; Davis, Michael; Kellermann, K. I.

doi:10.1086/112223

Cited by 81 publications

(44 citation statements)

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“…The spectral indices α below and α above were determined by fitting high-and low-frequency region of the spectra with a liner function in the log-log scale. Where a more accurate measurement of lowfrequency spectral index and peak frequency was necessary, we used measurements of other authors at the frequencies 74, 80, 151, 178, 232, 318, 325, 365, and 408 MHz (Cohen et al 2007;Pauliny-Toth et al 1978;Stanghellini et al 1998;Wright & Otrupcek 1990;Zhang et al 1997;Kuehr et al 1981;Rengelink et al 1997;Douglas et al 1996;Large et al 1981).…”

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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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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“…[2], [3]). An accommodation of these results was suggested by Shaver and Pierre [4] and by Shaver [5] who showed that the large-scale deviations could be due to the supergalaxy, a possibility which had been noted by Pauliny-Toth et al in 1978 [6]. As to the influence of other superclusters, or indeed the cellular structure of the universe in which galaxies cluster on scales up to at least 100 h' 1 Mpc (e.g.…”

Section: Introductionmentioning

confidence: 90%

Mapping Large-Scale Structure with Radio Sources

Wall

Benn

Loan

1996

Symp. - Int. Astron. Union

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In regions away from the Galactic plane, formal tests indicate an isotropic, random and independent distribution of radio sources on the sky (e.g.[1], although there are strong indications of large-scale anomalies (e.g.[2], [3]). An accommodation of these results was suggested by Shaver and Pierre [4] and by Shaver [5] who showed that the large-scale deviations could be due to the supergalaxy, a possibility which had been noted by Pauliny-Tothet al.in 1978 [6]. As to the influence ofothersuperclusters, or indeed the cellular structure of the universe in which galaxies cluster on scales up to at least 100h−1Mpc (e.g.[7]), at what flux-density level does this large-scale structure become apparent? Conversely, what can be learnt about structure on the largest scales through the sky distribution of radio sources? Here we describe three investigations in various stages of completion which consider these issues.

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“…The radio flux density of 0402+379 at 5 GHz is 1.1 Jy (Pauliny-Toth et al 1978;Becker et al 1991) which is a radio luminosity of 7 × 10 31 ergs sec −1 Hz −1 . This is in agreement with the X-ray to 5 GHz radio luminosity correlation of Brinkmann et al (2000).…”

Section: The Host Galaxymentioning

confidence: 96%

A Compact Supermassive Binary Black Hole System

Rodriguez¹,

Taylor²,

Zavala³

et al. 2006

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We report on the discovery of a supermassive binary black hole system in the radio galaxy 0402+379, with a projected separation between the two black holes of just 7.3 pc. This is the closest black hole pair yet found by more than two orders of magnitude. These results are based upon recent multi-frequency observations using the Very Long Baseline Array (VLBA) which reveal two compact, variable, flat-spectrum, active nuclei within the elliptical host galaxy of 0402+379. Multiepoch observations from the VLBA also provide constraints on the total mass and dynamics of the system. Low spectral resolution spectroscopy using the Hobby-Eberly Telescope indicates two velocity systems with a combined mass of the two black holes of ∼ 1.5 × 10 8 M ⊙ . The two nuclei appear stationary while the jets emanating from the weaker of the two nuclei appear to move out and terminate in bright hot spots. The discovery of this system has implications for the number of close binary black holes that might be sources of gravitational radiation. Green Bank Telescope observations at 22 GHz to search for water masers in this interesting system are also presented.

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The 5 GHz strong source surveys. IV - Survey of the area between declination 35 and 70 degrees and summary of source counts, spectra and optical identifications

Cited by 81 publications

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

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

Mapping Large-Scale Structure with Radio Sources

A Compact Supermassive Binary Black Hole System

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