Spectral variability in faint high-frequency peakers

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چکیده

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منابع مشابه

High Frequency Peakers

There is quite a clear anticorrelation between the intrinsic peak frequency and the overall radio source size in Compact Steep Spectrum (CSS) and GHz Peaked Spectrum (GPS) radio sources as shown by O’Dea (1998). This feature is interpreted in terms of synchrotron self-absorption (although free-free absorption may play a role as well) of the radiation emitted by a small radio source which is gro...

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Constraining the nature of High Frequency Peakers I . The spectral variability

Aims. We investigate the spectral characteristics of 51 candidate High Frequency Peakers (HFPs), from the “bright” HFP sample, in order to determine the nature of each object, and to obtain a smaller sample of genuine young radio sources. Methods. Simultaneous multi-frequency VLA observations carried out at various epochs have been used to detect flux density and spectral shape variability in o...

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Optical identifications of High Frequency Peakers⋆

Abstract. We present CCD observations of 13 objects from a complete sample of 55 bright High Frequency Peaker (HFP) radio sources, and provide optical identification for 12 of them. Images in R and V filters have been used to derive some additional information concerning the host of the radio source. Three hosts are likely to be galaxies, one resulted slightly extended, while the remaining 8 ar...

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VLBA images of High Frequency Peakers

We propose a morphological classification based on the parsec scale structure of fifty-one High Frequency Peakers (HFPs) from the “bright” HFP sample. VLBA images at two adjacent frequencies (chosen among 8.4, 15.3, 22.2 and 43.2 GHz) have been used to investigate the morphological properties of the HFPs in the optically thin part of their spectrum. We confirm that there is quite a clear distin...

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AND ASTROPHYSICS High Frequency Peakers : I . The Bright Sample

Here we present a sample of sources with convex radio spectra peaking at frequencies above a few GHz. We call these radio sources High Frequency Peakers (HFPs). This sample extends to higher turnover frequencies than the samples of Compact Steep Spectrum (CSS) and GHz Peaked Spectrum (GPS) radio sources. HFPs are rare due to the strong bias against them caused by their turnover occurring at fre...

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ژورنال

عنوان ژورنال: Monthly Notices of the Royal Astronomical Society

سال: 2010

ISSN: 0035-8711

DOI: 10.1111/j.1365-2966.2010.17179.x