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Lookup NU author(s): Dr David Rosario
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2022. The Author(s). Published by the American Astronomical Society. The observed optical colors of quasars are generally interpreted in one of two frameworks: unified models that attribute the color to the random orientation of the accretion disk along the line of sight, and evolutionary models that invoke connections between quasar systems and their environments. We test these schemas by probing the dark matter halo environments of optically selected quasars as a function of g - i optical color by measuring the two-point correlation functions of ∼0.34 million eBOSS quasars as well as the gravitational deflection of cosmic microwave background photons around ∼0.66 million XDQSO photometric quasar candidates. We do not detect a trend of halo bias with optical color through either analysis, finding that optically selected quasars at 0.8 < z < 2.2 occupy halos of characteristic mass M h ∼3 × 1012 h -1 M ⊙ regardless of their color. This result implies that a quasar's large-scale halo environment is not strongly connected to its observed optical color. We also confirm the findings of fundamental differences in the radio properties of red and blue quasars by stacking 1.4 GHz FIRST images at their positions, suggesting the observed differences cannot be attributed to orientation. Instead, the differences between red and blue quasars likely arise on nuclear-galactic scales, perhaps owing to reddening by a nuclear dusty wind. Finally, we show that optically selected quasars' halo environments are also independent of their r - W2 optical-infrared colors, while previous work has suggested that mid-infrared-selected obscured quasars occupy more massive halos. We discuss the implications of this result for models of quasar and galaxy coevolution.
Author(s): Petter GC, Hickox RC, Alexander DM, Geach JE, Myers AD, Rosario DJ, Fawcett VA, Klindt L, Whalen KE
Publication type: Article
Publication status: Published
Journal: Astrophysical Journal
Year: 2022
Volume: 927
Online publication date: 02/03/2022
Acceptance date: 18/01/2022
Date deposited: 28/03/2022
ISSN (print): 0004-637X
ISSN (electronic): 1538-4357
Publisher: IOP Publishing Ltd
URL: https://doi.org/10.3847/1538-4357/ac4d31
DOI: 10.3847/1538-4357/ac4d31
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