Results 31 to 40 of about 17,110 (224)
Quasar-galaxy associations [PDF]
Monthly Notices of the Royal Astronomical Society, 1995 uuencoded Postscript file (including figures and tables), SUSSEX-AST 94/8 ...
Thomas, P. A. +2 more
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A Hubble Diagram for Quasars [PDF]
Frontiers in Astronomy and Space Sciences, 2018 The cosmological model is at present not tested between the redshift of the farthest observed supernovae (z ~ 1.4) and that of the Cosmic Microwave Background (z ~ 1,100). Here we introduce a new method to measure the cosmological parameters: we show that quasars can be used as "standard candles" by employing the non-linear relation between their ...
Susanna Bisogni +4 more
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Finding Multiply Lensed and Binary Quasars in the DESI Legacy Imaging Surveys
The Astrophysical Journal Supplement Series, 2023 The time delay between multiple images of strongly lensed quasars is a powerful tool for measuring the Hubble constant ( H _0 ). To achieve H _0 measurements with higher precision and accuracy using the time delay, it is crucial to expand the sample of ...
C. Dawes +6 more
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The Infrared Traced Star Formation Rates of Associated Absorption Lines Quasars
The Astrophysical JournalSome optically selected quasars exhibit Mg ii- associated absorption lines (AALs), and their origin remains unclear. In this paper, we compile a sample of 1769 quasars, with or without Mg ii AALs, of which 1689 are far-infrared (FIR) detected quasars and
Zhe-Geng Chen +6 more
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Constraining the anisotropy of the Universe with the X-ray and UV fluxes of quasars
European Physical Journal C: Particles and Fields, 2021 We test the anisotropy in the Finslerian cosmological model with the X-ray and ultraviolet (UV) fluxes of quasars. The 2015 and 2020 compilations of quasars are used in the cosmological constraints.
Dong Zhao, Jun-Qing Xia
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Load Distributing Metamaterials Via Discrete Optimization
Advanced Functional Materials, EarlyView.Mechanical metamaterials are computationally optimized to homogenize transmitted forces by minimizing the spread of reaction forces. The resulting architectures transform localized loading into broader, more uniform force distributions and experimentally demonstrate robust load spreading under quasi‐static and impact loading.
Andrea Detry +6 more
wiley +1 more source
The Astrophysical JournalWe present an analysis of near-infrared photometry of 59 quasars at 5.83 −24 mag) of the sample. This luminosity trend may support the idea that red quasars represent an evolutionary stage preceding unobscured quasars, often invoked in the merger-driven
Ryo Iwamoto +10 more
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Gaia Space Mission and Quasars
Frontiers in Astronomy and Space Sciences, 2017 Quasars are often considered to be point-like objects. This is largely true and allows for an excellent alignment of the optical positional reference frame of the ongoing ESA mission Gaia with the International Celestial Reference Frame.
Tomaž Zwitter
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Principal Component‐Based Classification of Blazar Candidates of Uncertain Type in the 4FGL/LAT
Astronomische Nachrichten, EarlyView.ABSTRACT We adopted principal component analysis (PCA), linear discriminant analysis (LDA), and support vector machines (SVM), to study classification for a sample of 2708 Fermi blazars: 1142 BL Lac objects (BLLs), 759 flat spectrum radio quasars (FSRQs), and 807 blazar candidates of uncertain type (BCUs).
Wen‐Xin Yang +13 more
wiley +1 more source
New Astronomy Reviews, 2000 We propose a simple unifying structure for the inner regions of quasars and AGN. This empirically derived model links together the BALs, the narrow UV/X-ray ionized absorbers, the BELR, and the Compton scattering/fluorescing regions into a single structure. The model also suggests an origin for the large-scale bi-conical outflows.
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