Eddington ratio governs the equivalent width of Mg II emission line in active galactic nuclei

Xiao Bo Dong; Ting Gui Wang; Jian Guo Wang; Xiaohui Fan; Huiyuan Wang; Hongyan Zhou; Weimin Yuan

doi:10.1088/0004-637X/703/1/L1

Eddington ratio governs the equivalent width of Mg II emission line in active galactic nuclei

Xiao Bo Dong, Ting Gui Wang, Jian Guo Wang, Xiaohui Fan, Huiyuan Wang, Hongyan Zhou, Weimin Yuan

Astronomy

Research output: Contribution to journal › Article › peer-review

49 Scopus citations

Abstract

We have investigated the ensemble regularities of the equivalent widths (EWs) of Mg II λ2800 emission line of active galactic nuclei (AGNs), using a uniformly selected sample of 2092 Seyfert 1 galaxies and quasars at 0.45 ≤ z ≤ 0.8 in the spectroscopic data set of the Sloan Digital Sky Survey Fourth Data Release. We find a strong correlation between the EW of Mg II and the AGN Eddington ratio (L/L _Edd): EW(Mg II) (L/L _Edd)^-0.4. Furthermore, for AGNs with the same L/L _Edd, their EWs of Mg II show no correlation with luminosity, black hole mass, or line width, and the Mg II line luminosity is proportional to continuum luminosity, as expected by photoionization theory. Our result shows that Mg II EW is not dependent on luminosity, but is solely governed by L/L _Edd.

Original language	English (US)
Pages (from-to)	L1-L5
Journal	Astrophysical Journal
Volume	703
Issue number	1 PART 2
DOIs	https://doi.org/10.1088/0004-637X/703/1/L1
State	Published - 2009

Keywords

Line: formation
Quasars: emission lines
Quasars: general
Radiation mechanisms: general

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.1088/0004-637X/703/1/L1

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title = "Eddington ratio governs the equivalent width of Mg II emission line in active galactic nuclei",

abstract = "We have investigated the ensemble regularities of the equivalent widths (EWs) of Mg II λ2800 emission line of active galactic nuclei (AGNs), using a uniformly selected sample of 2092 Seyfert 1 galaxies and quasars at 0.45 ≤ z ≤ 0.8 in the spectroscopic data set of the Sloan Digital Sky Survey Fourth Data Release. We find a strong correlation between the EW of Mg II and the AGN Eddington ratio (L/L Edd): EW(Mg II) (L/L Edd)-0.4. Furthermore, for AGNs with the same L/L Edd, their EWs of Mg II show no correlation with luminosity, black hole mass, or line width, and the Mg II line luminosity is proportional to continuum luminosity, as expected by photoionization theory. Our result shows that Mg II EW is not dependent on luminosity, but is solely governed by L/L Edd.",

keywords = "Line: formation, Quasars: emission lines, Quasars: general, Radiation mechanisms: general",

author = "Dong, {Xiao Bo} and Wang, {Ting Gui} and Wang, {Jian Guo} and Xiaohui Fan and Huiyuan Wang and Hongyan Zhou and Weimin Yuan",

year = "2009",

doi = "10.1088/0004-637X/703/1/L1",

language = "English (US)",

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}

TY - JOUR

T1 - Eddington ratio governs the equivalent width of Mg II emission line in active galactic nuclei

AU - Dong, Xiao Bo

AU - Wang, Ting Gui

AU - Wang, Jian Guo

AU - Fan, Xiaohui

AU - Wang, Huiyuan

AU - Zhou, Hongyan

AU - Yuan, Weimin

PY - 2009

Y1 - 2009

N2 - We have investigated the ensemble regularities of the equivalent widths (EWs) of Mg II λ2800 emission line of active galactic nuclei (AGNs), using a uniformly selected sample of 2092 Seyfert 1 galaxies and quasars at 0.45 ≤ z ≤ 0.8 in the spectroscopic data set of the Sloan Digital Sky Survey Fourth Data Release. We find a strong correlation between the EW of Mg II and the AGN Eddington ratio (L/L Edd): EW(Mg II) (L/L Edd)-0.4. Furthermore, for AGNs with the same L/L Edd, their EWs of Mg II show no correlation with luminosity, black hole mass, or line width, and the Mg II line luminosity is proportional to continuum luminosity, as expected by photoionization theory. Our result shows that Mg II EW is not dependent on luminosity, but is solely governed by L/L Edd.

AB - We have investigated the ensemble regularities of the equivalent widths (EWs) of Mg II λ2800 emission line of active galactic nuclei (AGNs), using a uniformly selected sample of 2092 Seyfert 1 galaxies and quasars at 0.45 ≤ z ≤ 0.8 in the spectroscopic data set of the Sloan Digital Sky Survey Fourth Data Release. We find a strong correlation between the EW of Mg II and the AGN Eddington ratio (L/L Edd): EW(Mg II) (L/L Edd)-0.4. Furthermore, for AGNs with the same L/L Edd, their EWs of Mg II show no correlation with luminosity, black hole mass, or line width, and the Mg II line luminosity is proportional to continuum luminosity, as expected by photoionization theory. Our result shows that Mg II EW is not dependent on luminosity, but is solely governed by L/L Edd.

KW - Line: formation

KW - Quasars: emission lines

KW - Quasars: general

KW - Radiation mechanisms: general

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U2 - 10.1088/0004-637X/703/1/L1

DO - 10.1088/0004-637X/703/1/L1

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SN - 0004-637X

VL - 703

SP - L1-L5

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 1 PART 2

ER -

Eddington ratio governs the equivalent width of Mg II emission line in active galactic nuclei

Abstract

Keywords

ASJC Scopus subject areas

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