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Main Authors: Aradhey, Anish S., Constantin, Anca, Vogeley, Michael S., Douglass, Kelly A.
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2507.10921
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author Aradhey, Anish S.
Constantin, Anca
Vogeley, Michael S.
Douglass, Kelly A.
author_facet Aradhey, Anish S.
Constantin, Anca
Vogeley, Michael S.
Douglass, Kelly A.
contents Observations and theoretical simulations suggest that the large scale environment plays a significant role in how galaxies form and evolve and, in particular, whether and when galaxies host an actively accreting supermassive black hole in their center (i.e., an Active Galactic Nucleus, or AGN). One signature of AGN activity is luminosity variability, which appears in the mid-infrared (mid-IR) when circumnuclear dust reprocesses UV and optical photons from the AGN accretion disk. We present here a suite of constraints on the fraction of AGN activity in the most underdense regions of the universe (cosmic voids) relative to the rest of the universe (cosmic walls) by using ~12 years of combined multi-epoch data from AllWISE and NEOWISE to quantify mid-IR variability. We find clear evidence for a larger mid-IR variability-AGN fraction among high and moderate-luminosity void galaxies compared to their wall counterparts. We also show that mid-IR variability identifies a rather large and unique population of AGNs, the majority of which have eluded detection using more traditional AGN-selection methods such as single-epoch mid-IR color selection. The fraction of these newly-recovered AGNs is larger among galaxies in voids, suggesting once again more prolific AGN activity in the most underdense large scale structures of the universe.
format Preprint
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institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Quantifying the Active Galactic Nuclei Fraction in Cosmic Voids via Mid-Infrared Variability
Aradhey, Anish S.
Constantin, Anca
Vogeley, Michael S.
Douglass, Kelly A.
Astrophysics of Galaxies
Observations and theoretical simulations suggest that the large scale environment plays a significant role in how galaxies form and evolve and, in particular, whether and when galaxies host an actively accreting supermassive black hole in their center (i.e., an Active Galactic Nucleus, or AGN). One signature of AGN activity is luminosity variability, which appears in the mid-infrared (mid-IR) when circumnuclear dust reprocesses UV and optical photons from the AGN accretion disk. We present here a suite of constraints on the fraction of AGN activity in the most underdense regions of the universe (cosmic voids) relative to the rest of the universe (cosmic walls) by using ~12 years of combined multi-epoch data from AllWISE and NEOWISE to quantify mid-IR variability. We find clear evidence for a larger mid-IR variability-AGN fraction among high and moderate-luminosity void galaxies compared to their wall counterparts. We also show that mid-IR variability identifies a rather large and unique population of AGNs, the majority of which have eluded detection using more traditional AGN-selection methods such as single-epoch mid-IR color selection. The fraction of these newly-recovered AGNs is larger among galaxies in voids, suggesting once again more prolific AGN activity in the most underdense large scale structures of the universe.
title Quantifying the Active Galactic Nuclei Fraction in Cosmic Voids via Mid-Infrared Variability
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2507.10921