منابع مشابه
Scintillation-induced Variability in Radio Absorption Spectra against Extragalactic Sources
Abstract. Spectral features absorbed against some radio quasars exhibit ∼ 50mJy variations, with the lines varying both relative to the continuum and, when several lines are present, even relative to one another. We point out that such variability can be expected as a consequence of refractive scintillation caused by the interstellar medium of our Galaxy. Scintillation can cause independent var...
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We present a fitting function to describe the statistics of flux modulations caused by interstellar scintillation. The function models a very general quantity: the cross-correlation of the flux observed from a compact radio source of finite angular size observed at two frequencies and at two positions or times. The formula will be useful for fitting data from sources such as intra-day variables...
متن کاملRadio scintillation of gamma-ray-burst afterglows ?
Stars twinkle to the eye through atmospheric turbulence, but planets, because of their larger angular size, do not. Similarly, scintillation due to the local interstellar medium will modulate the radio flux of gamma-ray-burst afterglows and may permit indirect measurements of their angular sizes. The amplitude of refractive scintillation is of order ten percent at ten gigahertz unless the sourc...
متن کاملEstimating the Number of Wideband Radio Sources
In this paper, a new approach for estimating the number of wideband sources is proposed which is based on RSS or ISM algorithms. Numerical results show that the MDL-based and EIT-based proposed algorithm havea much better detection performance than that in EGM and AIC cases for small differences between the incident angles of sources. In addition, for similar conditions, RSS algorithm offers hi...
متن کاملSmall and young radio sources
It is currently accepted that compact and bright radio sources characterized by a convex spectrum peaking at frequencies ranging from 100 MHz to a few GHz are young objects. In this scenario, high frequency peaker (HFP) radio sources, with a turnover frequency higher than 5 GHz are good candidates to be extremely young radio sources with ages of up to a few thousand years. The knowledge of the ...
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ژورنال
عنوان ژورنال: International Astronomical Union Colloquium
سال: 2001
ISSN: 0252-9211
DOI: 10.1017/s0252921100000609