L. Barquín-González, S. Mateos, F. J. Carrera, I. Ordovás-Pascual, A. Alonso-Herrero, A. Caccianiga, N. Cardiel, A. Corral, R. M. Domínguez, I. García-Bernete, G. Mountrichas, P. Severgnini
{"title":"消光和AGN与宿主星系对比对AGN光学光谱分类的影响","authors":"L. Barquín-González, S. Mateos, F. J. Carrera, I. Ordovás-Pascual, A. Alonso-Herrero, A. Caccianiga, N. Cardiel, A. Corral, R. M. Domínguez, I. García-Bernete, G. Mountrichas, P. Severgnini","doi":"10.1051/0004-6361/202348948","DOIUrl":null,"url":null,"abstract":"The optical spectroscopic classification of active galactic nuclei (AGN) into type 1 and type 2 can be understood in the frame of the AGN unification models. However, it remains unclear which physical properties are driving the classification into intermediate sub-types (1.0, 1.2, 1.5, 1.8, 1.9). To shed light on this issue, we present an analysis of the effect of extinction and AGN and host galaxy luminosities on sub-type determination for a sample of 159 X-ray selected AGN with a complete and robust optical spectroscopic classification. The sample spans a rest-frame 2–10 keV X-ray luminosity range of 10<sup>42<sup/>–10<sup>46<sup/> erg s<sup>−1<sup/> and redshifts between 0.05 and 0.75. From the fitting of their ultraviolet-to-mid-infrared spectral energy distributions, we extracted the observed AGN over total AGN+galaxy contrast, optical/ultraviolet line-of-sight extinction, as well as host galaxy and AGN luminosities. The observed contrast exhibits a clear decline with sub-type, distinguishing two main groups: 1.0–5 and 1.8–2. This difference is partly driven by an increase in extinction following the same trend. Nevertheless, 50% of 1.9s and 2s lack sufficient extinction to explain the lack of detection of broad emission lines, unveiling the necessity of an additional effect. Our findings show that 1.8–2s preferentially live in host galaxies with higher luminosities while displaying similar intrinsic AGN luminosities to 1.0–5s. Consequently, the AGN to host galaxy luminosity ratio diminishes, hindering the detection of the emission of the broad emission lines, resulting in the 1.8–2 classification of those with insufficient extinction. Thus, the combination of increasing extinction and decreasing AGN over galaxy luminosity ratio, mainly driven by an increasing host galaxy luminosity, constitutes the main reasons behind the sub-type classification into 1.0–5 and 1.8–2.","PeriodicalId":8571,"journal":{"name":"Astronomy & Astrophysics","volume":null,"pages":null},"PeriodicalIF":5.4000,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Extinction and AGN over host galaxy contrast effects on the optical spectroscopic classification of AGN⋆\",\"authors\":\"L. Barquín-González, S. Mateos, F. J. Carrera, I. Ordovás-Pascual, A. Alonso-Herrero, A. Caccianiga, N. Cardiel, A. Corral, R. M. Domínguez, I. García-Bernete, G. Mountrichas, P. Severgnini\",\"doi\":\"10.1051/0004-6361/202348948\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"The optical spectroscopic classification of active galactic nuclei (AGN) into type 1 and type 2 can be understood in the frame of the AGN unification models. However, it remains unclear which physical properties are driving the classification into intermediate sub-types (1.0, 1.2, 1.5, 1.8, 1.9). To shed light on this issue, we present an analysis of the effect of extinction and AGN and host galaxy luminosities on sub-type determination for a sample of 159 X-ray selected AGN with a complete and robust optical spectroscopic classification. The sample spans a rest-frame 2–10 keV X-ray luminosity range of 10<sup>42<sup/>–10<sup>46<sup/> erg s<sup>−1<sup/> and redshifts between 0.05 and 0.75. From the fitting of their ultraviolet-to-mid-infrared spectral energy distributions, we extracted the observed AGN over total AGN+galaxy contrast, optical/ultraviolet line-of-sight extinction, as well as host galaxy and AGN luminosities. The observed contrast exhibits a clear decline with sub-type, distinguishing two main groups: 1.0–5 and 1.8–2. This difference is partly driven by an increase in extinction following the same trend. Nevertheless, 50% of 1.9s and 2s lack sufficient extinction to explain the lack of detection of broad emission lines, unveiling the necessity of an additional effect. Our findings show that 1.8–2s preferentially live in host galaxies with higher luminosities while displaying similar intrinsic AGN luminosities to 1.0–5s. Consequently, the AGN to host galaxy luminosity ratio diminishes, hindering the detection of the emission of the broad emission lines, resulting in the 1.8–2 classification of those with insufficient extinction. Thus, the combination of increasing extinction and decreasing AGN over galaxy luminosity ratio, mainly driven by an increasing host galaxy luminosity, constitutes the main reasons behind the sub-type classification into 1.0–5 and 1.8–2.\",\"PeriodicalId\":8571,\"journal\":{\"name\":\"Astronomy & Astrophysics\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":5.4000,\"publicationDate\":\"2024-07-05\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Astronomy & Astrophysics\",\"FirstCategoryId\":\"101\",\"ListUrlMain\":\"https://doi.org/10.1051/0004-6361/202348948\",\"RegionNum\":2,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"ASTRONOMY & ASTROPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Astronomy & Astrophysics","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1051/0004-6361/202348948","RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
Extinction and AGN over host galaxy contrast effects on the optical spectroscopic classification of AGN⋆
The optical spectroscopic classification of active galactic nuclei (AGN) into type 1 and type 2 can be understood in the frame of the AGN unification models. However, it remains unclear which physical properties are driving the classification into intermediate sub-types (1.0, 1.2, 1.5, 1.8, 1.9). To shed light on this issue, we present an analysis of the effect of extinction and AGN and host galaxy luminosities on sub-type determination for a sample of 159 X-ray selected AGN with a complete and robust optical spectroscopic classification. The sample spans a rest-frame 2–10 keV X-ray luminosity range of 1042–1046 erg s−1 and redshifts between 0.05 and 0.75. From the fitting of their ultraviolet-to-mid-infrared spectral energy distributions, we extracted the observed AGN over total AGN+galaxy contrast, optical/ultraviolet line-of-sight extinction, as well as host galaxy and AGN luminosities. The observed contrast exhibits a clear decline with sub-type, distinguishing two main groups: 1.0–5 and 1.8–2. This difference is partly driven by an increase in extinction following the same trend. Nevertheless, 50% of 1.9s and 2s lack sufficient extinction to explain the lack of detection of broad emission lines, unveiling the necessity of an additional effect. Our findings show that 1.8–2s preferentially live in host galaxies with higher luminosities while displaying similar intrinsic AGN luminosities to 1.0–5s. Consequently, the AGN to host galaxy luminosity ratio diminishes, hindering the detection of the emission of the broad emission lines, resulting in the 1.8–2 classification of those with insufficient extinction. Thus, the combination of increasing extinction and decreasing AGN over galaxy luminosity ratio, mainly driven by an increasing host galaxy luminosity, constitutes the main reasons behind the sub-type classification into 1.0–5 and 1.8–2.
期刊介绍:
Astronomy & Astrophysics is an international Journal that publishes papers on all aspects of astronomy and astrophysics (theoretical, observational, and instrumental) independently of the techniques used to obtain the results.