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Main Authors: Chen, Zhi-fu, Chen, Zhe-Geng, Peng, Xing-long, Huang, Wei-rong
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2410.18401
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author Chen, Zhi-fu
Chen, Zhe-Geng
Peng, Xing-long
Huang, Wei-rong
author_facet Chen, Zhi-fu
Chen, Zhe-Geng
Peng, Xing-long
Huang, Wei-rong
contents Radio spectral shape of quasars can provide insight into the ages of quasars. We have compiled data for 1804 quasars with $z\lesssim1$ from the Sloan Digital Sky Survey (SDSS). Additionally, these quasars were also mapped by the Low-Frequency Array at 144 MHz and the Very Large Array Sky Survey at 3000 MHz. The radio spectral index, designated as $α^{\rm 144}_{\rm 3000}$ (with $S(ν)\proptoν^α$), is analyzed between 144 MHz and 3000 MHz as a proxy for the ages of quasars. We measure the [O III] $λ$5007 emission line in the SDSS spectra. A strong correlation was found between the equivalent width of the core component of the [O III] $λ$5007 emission line and $α^{\rm 144}_{\rm 3000}$. This relationship suggests that the core component of the [O III] $λ$5007 emission line could potentially serve as a surrogate for the evolutionary stage of a quasar. The quasars at an early stage of evolutions tend to show weaker [O III] $λ$5007 emission, while older quasars exhibit stronger [O III] $λ$5007 emission.
format Preprint
id arxiv_https___arxiv_org_abs_2410_18401
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Narrow [O III] emission lines as a potential proxy for the evolutionary stage of quasars
Chen, Zhi-fu
Chen, Zhe-Geng
Peng, Xing-long
Huang, Wei-rong
Astrophysics of Galaxies
Radio spectral shape of quasars can provide insight into the ages of quasars. We have compiled data for 1804 quasars with $z\lesssim1$ from the Sloan Digital Sky Survey (SDSS). Additionally, these quasars were also mapped by the Low-Frequency Array at 144 MHz and the Very Large Array Sky Survey at 3000 MHz. The radio spectral index, designated as $α^{\rm 144}_{\rm 3000}$ (with $S(ν)\proptoν^α$), is analyzed between 144 MHz and 3000 MHz as a proxy for the ages of quasars. We measure the [O III] $λ$5007 emission line in the SDSS spectra. A strong correlation was found between the equivalent width of the core component of the [O III] $λ$5007 emission line and $α^{\rm 144}_{\rm 3000}$. This relationship suggests that the core component of the [O III] $λ$5007 emission line could potentially serve as a surrogate for the evolutionary stage of a quasar. The quasars at an early stage of evolutions tend to show weaker [O III] $λ$5007 emission, while older quasars exhibit stronger [O III] $λ$5007 emission.
title Narrow [O III] emission lines as a potential proxy for the evolutionary stage of quasars
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2410.18401