Results 1 to 10 of about 12,830 (233)
The Astrophysical Journal, 2023 We explore reprocessing models for a sample of 17 hypervariable quasars, taken from the Sloan Digital Sky Survey Reverberation Mapping project, which all show coordinated optical luminosity hypervariability with amplitudes of factors ≳2 between 2014 and ...
Tatsuya Akiba +7 more
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Exploring galaxy mass profiles in strongly lensed quasars with upcoming Roman Space Telescope observations [PDF]
EPJ Web of ConferencesStrong gravitational lensing of quasars is a powerful tool for probing cosmological parameters, tracing galaxy evolution, and investigating the internal structure of quasars.
Guliqani Esmeralda +2 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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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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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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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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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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Shedding New Light on Weak Emission-line Quasars in the C iv–Hβ Parameter Space
The Astrophysical Journal, 2023 Weak emission-line quasars (WLQs) are a subset of type 1 quasars that exhibit extremely weak Ly α + N v λ 1240 and/or C iv λ 1549 emission lines. We investigate the relationship between emission-line properties and accretion rate for a sample of 230 ...
Trung Ha +22 more
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Quasar Luminosity Function at z = 7
The Astrophysical Journal Letters, 2023 We present the quasar luminosity function (LF) at z = 7, measured with 35 spectroscopically confirmed quasars at 6.55 < z < 7.15. The sample of 22 quasars from the Subaru High- z Exploration of Low-Luminosity Quasars (SHELLQs) project, combined with 13 ...
Yoshiki Matsuoka +43 more
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Red Type-1 Quasars after Cosmic Noon and Impact on L UV-related Quasar Statistics
The Astrophysical JournalOver the past decades, nearly a million quasars have been explored to shed light on the evolution of supermassive black holes and galaxies. The ultraviolet-to-optical spectra of type-1 quasars particularly offer insights into their black hole activities.
Yongjung Kim +3 more
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