Atomic and molecular absorption in redshifted radio sources
نویسندگان
چکیده
منابع مشابه
A Survey for Redshifted Molecular and Atomic Absorption Lines
We present the results of a z > 2.9 survey for H I 21-cm and molecular absorption in the hosts of radio quasars using the Giant Metrewave Radio Telescope and the Tidbinbilla 70m telescope. Although the atomic gas has been searched to limits capable of detecting most known absorption systems, no H I was detected in any of the ten sources. Previously published searches, which are overwhelmingly a...
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We have made radioand millimeter-wavelength interferometric observations of a variety of molecular absorption lines toward the gravitational lens systems B0218+357 and PKS 1830−211. The absorption occurs in the lensing galaxies at redshifts of 0.685 and 0.89, respectively. The high spatial resolution of our VLA and VLBA observations allows imaging of the background continuum emission and the ab...
متن کاملA Survey for Redshifted Molecular and Atomic Absorption Lines I. The Parkes Half-Jansky Flat-Spectrum Red Quasar Sample
We are currently undertaking a large survey for redshifted atomic and molecular absorption lines at radio frequencies. In this paper we present the results from the first phase of this: the search for H I 21-cm and OH 18-cm absorption lines in the hosts of reddened quasars and radio galaxies. Although we observed each source for up to several hours with two of the world’s most sensitive radio t...
متن کاملMeasuring Changes in the Fundamental Constants with Redshifted Radio Absorption Lines
Strong evidence has recently emerged for a variation in the fine structure constant, α ≡ e/h̄c, over the history of the Universe. This was concluded from a detailed study of the relative positions of redshifted optical quasar absorption spectra. However, radio absorption lines at high redshift offer a much higher sensitivity to a cosmological change in α than optical lines. Furthermore, through ...
متن کاملScintillation-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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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 2017
ISSN: 0035-8711,1365-2966
DOI: 10.1093/mnras/stx408