Zhi-fu Chen, Zhe-Geng Chen, Xing-long Peng and Wei-rong Huang
{"title":"Narrow [O iii] Emission Lines as a Potential Proxy for the Evolutionary Stage of Quasars","authors":"Zhi-fu Chen, Zhe-Geng Chen, Xing-long Peng and Wei-rong Huang","doi":"10.3847/1538-4357/ad79ff","DOIUrl":null,"url":null,"abstract":"Radio spectral shape of quasars can provide insight into the ages of quasars. We have compiled data for 1804 quasars with z ≲ 1 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 (with S(ν) ∝ να), is analyzed between 144 and 3000 MHz as a proxy for the ages of quasars. We measure the [O III] λ5007 emission line in the SDSS spectra. A strong correlation was found between the equivalent width of the core component of the [O III] λ5007 emission line and . This relationship suggests that the core component of the [O III] λ5007 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] λ5007 emission, while older quasars exhibit stronger [O III] λ5007 emission.","PeriodicalId":501813,"journal":{"name":"The Astrophysical Journal","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"The Astrophysical Journal","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.3847/1538-4357/ad79ff","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Radio spectral shape of quasars can provide insight into the ages of quasars. We have compiled data for 1804 quasars with z ≲ 1 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 (with S(ν) ∝ να), is analyzed between 144 and 3000 MHz as a proxy for the ages of quasars. We measure the [O III] λ5007 emission line in the SDSS spectra. A strong correlation was found between the equivalent width of the core component of the [O III] λ5007 emission line and . This relationship suggests that the core component of the [O III] λ5007 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] λ5007 emission, while older quasars exhibit stronger [O III] λ5007 emission.