Observations of intrahour variable quasars: scattering in our Galactic neighbourhood

Q4 Physics and Astronomy

Astronomical and Astrophysical Transactions Pub Date : 2007-09-10 DOI:10.1080/10556790701596804

H. Bignall, D. Jauncey, J. Lovell, A. Tzioumis, J. Macquart, L. Kedziora-Chudczer

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引用次数: 2

Abstract

Abstract Interstellar scintillation (ISS) has been established as the cause of the random variations seen at centimetre wavelengths in many compact radio sources on timescales of a day or less. Observations of ISS can be used to probe structure both in the ionized insterstellar medium of the Galaxy and in the extragalactic sources themselves down to μ as scales. A few quasars have been found to show large amplitude scintillations on unusually rapid, intrahour timescales. This has been shown to be due to weak scattering in very local Galactic ‘screens’, within a few tens of parsec of the Sun. The short variability timescales allow detailed study of the scintillation properties in relatively short observation periods with compact interferometric arrays. The three best-studied ‘intrahour variable’ quasars, PKS 0405−385, J1819+3845 and PKS 1257−326, have been instrumental in establishing ISS as the principal cause of intraday variability at centimetre wavelengths. Here we review the relevant results from obse...

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小时内可变类星体的观测:银河系附近的散射

星际闪烁(ISS)已经被确定为许多紧凑射电源在一天或更短的时间尺度上的厘米波长随机变化的原因。国际空间站的观测可以用来探测银河系电离的星际介质和河外源本身的结构，它们的尺度小到μ as。一些类星体已经被发现在异常快速的小时内的时间尺度上显示出剧烈的闪烁。这已经被证明是由于非常局部的银河“屏幕”的弱散射，在太阳的几十秒差距内。短变异性时间尺度允许在相对较短的观测周期内用紧凑的干涉阵列详细研究闪烁特性。三个被研究得最好的“小时内变”类星体，PKS 0405 - 385, J1819+3845和PKS 1257 - 326，在确定ISS是厘米波长内变化的主要原因方面发挥了重要作用。在这里，我们回顾肥胖症的相关结果。

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来源期刊

Astronomical and Astrophysical Transactions Physics and Astronomy-Instrumentation

CiteScore

0.40

自引率

0.00%

发文量

期刊介绍： Astronomical and Astrophysical Transactions (AApTr) journal is being published jointly by the Euro-Asian Astronomical Society and Cambridge Scientific Publishers, The journal provides a forum for the rapid publication of material from all modern and classical fields of astronomy and astrophysics, as well as material concerned with astronomical instrumentation and related fundamental sciences. It includes both theoretical and experimental original research papers, short communications, review papers and conference reports.