The Sloan Digital Sky Survey Reverberation Mapping Project: Mg ii Lag Results from Four Years of Monitoring

Homayouni, Y.; Trump, Jonathan R.; Grier, C. J.; Horne, K.; Shen, Yue; Brandt, W. N.; Dawson, Kyle; Alvarez, Gloria Fonseca; Green, Paul; Hall, Patrick B.; Santisteban, J. V. Hernández; Ho, Luis C.; Kinemuchi, Karen; Kochanek, C. S.; Li, Jennifer I-Hsiu; Peterson, B. M.; Schneider, Donald P.; Starkey, D.; Bizyaev, Dmitry; Pan, Kaike; Oravetz, Daniel; Simmons, Audrey

doi:10.3847/1538-4357/ababa9

Cited by 81 publications

(94 citation statements)

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“…The relative impact of microlensing is larger in C III] when compared with Mg II, indicating that the emission region associated with this line is more compact. We obtain size estimates of ∼31 and ∼67 light-days for the C III] and Mg II emission lines, in good agreement with RM studies (see, e.g., Clavel et al 1991;Homayouni et al 2020;Wang et al 2020). The high impact of microlensing in the C IV emission line indicates that this line arises from a region of ∼16 light-days in size.…”

Section: Discussionsupporting

confidence: 90%

Microlensing of the broad emission lines in 27 gravitationally lensed quasars. Broad line region structure and kinematics

Fian,

Mediavilla,

Motta

et al. 2021

Preprint

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Aims. We aim to study the structure and kinematics of the broad line region (BLR) of a sample of 27 gravitationally lensed quasars with up to five different epochs of observation. This sample is composed of ∼100 spectra from the literature plus 22 unpublished spectra of 11 systems. Methods. We measure the magnitude differences in the broad emission line (BEL) wings and statistically model the distribution of microlensing magnifications to determine a maximum likelihood estimate for the sizes of the C IV, C III], and Mg II emitting regions. Results. The BELs in lensed quasars are expected to be magnified differently owing to the different sizes of the regions from which they originate. Focusing on the most common BELs in our spectra (C IV, C III], and Mg II), we find that the low-ionization line Mg II is only weakly affected by microlensing. In contrast, the high-ionization line C IV shows strong microlensing in some cases, indicating that its emission region is more compact. Thus, the BEL profiles are deformed differently depending on the geometry and kinematics of the corresponding emitting region. We detect microlensing in either the blue or the red wing (or in both wings with different amplitudes) of C IV in more than 50% of the systems and find outstanding asymmetries in the wings of QSO 0957+561, SDSS J1004+4112, SDSS J1206+4332, and SDSS J1339+1310. This observation indicates that the BLR is, in general, not spherically symmetric and supports the existence of two regions in the BLR, one insensitive to microlensing and another that only shows up when it is magnified by microlensing. Disregarding the existence of these two regions, our estimate for Mg II, R 1/2 = 67.3 +3.8 −15.7 √ M/M light-days, is in good agreement with previous results from smaller samples, while we obtain smaller sizes for the C III] and CIV lines, R 1/2 = 31.0 +1.9 −4.0 √ M/M light-days and R 1/2 = 15.5 +0.8 −3.9 √ M/M light-days, respectively.

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Section: Discussionsupporting

confidence: 90%

Microlensing of the broad emission lines in 27 gravitationally lensed quasars. Broad line region structure and kinematics

Fian,

Mediavilla,

Motta

et al. 2021

Preprint

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Section: Discussionsupporting

confidence: 90%

Microlensing of the broad emission lines in 27 gravitationally lensed quasars

Fian

Mediavilla²,

Motta³

et al. 2021

A&A

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Aims. We aim to study the structure and kinematics of the broad line region (BLR) of a sample of 27 gravitationally lensed quasars with up to five different epochs of observation. This sample is composed of ∼100 spectra from the literature plus 22 unpublished spectra of 11 systems. Methods. We measure the magnitude differences in the broad emission line (BEL) wings and statistically model the distribution of microlensing magnifications to determine a maximum likelihood estimate for the sizes of the C IV, C III], and Mg II emitting regions. Results. The BELs in lensed quasars are expected to be magnified differently owing to the different sizes of the regions from which they originate. Focusing on the most common BELs in our spectra (C IV, C III], and Mg II), we find that the low-ionization line Mg II is only weakly affected by microlensing. In contrast, the high-ionization line C IV shows strong microlensing in some cases, indicating that its emission region is more compact. Thus, the BEL profiles are deformed differently depending on the geometry and kinematics of the corresponding emitting region. We detect microlensing in either the blue or the red wing (or in both wings with different amplitudes) of C IV in more than 50% of the systems and find outstanding asymmetries in the wings of QSO 0957+561, SDSS J1004+4112, SDSS J1206+4332, and SDSS J1339+1310. This observation indicates that the BLR is, in general, not spherically symmetric and supports the existence of two regions in the BLR, one insensitive to microlensing and another that only shows up when it is magnified by microlensing. Disregarding the existence of these two regions, our estimate for Mg II, R1/2 = 67.3−15.7+3.8 √(M/M⊙) light-days, is in good agreement with previous results from smaller samples, while we obtain smaller sizes for the C III] and CIV lines, R1/2 = 31.0−4.0+1.9 √(M/M⊙) light-days and R1/2 = 15.5−3.9+0.8 √(M/M⊙) light-days, respectively.

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“…Of the three strong emission lines generally used to estimate central black hole masses, the R-L relationship is only well established for Hβ λ4861 (Bentz et al 2013 and references therein; but see the discussion in Section 3.3). Empirically establishing the R-L relationship for Mg II λ2798 (Clavel et al 1990(Clavel et al , 1991Reichert et al 1994;Metzroth et al 2006;Cackett et al 2015;Shen et al 2016;Lira et al 2018;Czerny et al 2019;Homayouni et al 2020;Zajaček et al 2020), as well as for C IV λ1549 (Clavel et al 1989(Clavel et al , 1990(Clavel et al , 1991Reichert et al 1994;Korista et al 1995;Rodríguez-Pascual et al 1997;Wanders et al 1997;O'Brien et al 1998;Peterson et al 2005;Metzroth et al 2006;Kaspi et al 2007;Trevese et al 2014;De Rosa et al 2015;Lira et al 2018;Grier et al 2019;Hoormann et al 2019),has been difficult because of the nature of the UV line variability and the high level of competition for suitable facilities.…”

Section: Reverberation-based Black Hole Massesmentioning

confidence: 99%

The Sloan Digital Sky Survey Reverberation Mapping Project: Estimating Masses of Black Holes in Quasars with Single-epoch Spectroscopy

Bontà

Peterson

Bentz

et al. 2020

ApJ

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It is well known that reverberation mapping of active galactic nuclei (AGNs) reveals a relationship between AGN luminosity and the size of the broad-line region, and that use of this relationship, combined with the Doppler width of the broad emission line, enables an estimate of the mass of the black hole at the center of the active nucleus based on a single spectrum. An unresolved key issue is the choice of parameter used to characterize the line width, either FWHM or line dispersion s line (the square root of the second moment of the line profile). We argue here that use of FWHM introduces a bias, stretching the mass scale such that high masses are overestimated and low masses are underestimated. Here we investigate estimation of black hole masses in AGNs based on individual or "singleepoch" observations, with a particular emphasis in comparing mass estimates based on line dispersion and FWHM. We confirm the recent findings that, in addition to luminosity and line width, a third parameter is required to obtain accurate masses, and that parameter seems to be Eddington ratio. We present simplified empirical formulae for estimating black hole masses from the Hβ λ4861 and C IV λ1549 emission lines. While the AGN continuum luminosity at 5100 Å is usually used to predict the Hβ reverberation lag, we show that the luminosity of the Hβ broad component can be used instead without any loss of precision, thus eliminating the difficulty of accurately accounting for the host-galaxy contribution to the observed luminosity.

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The Sloan Digital Sky Survey Reverberation Mapping Project: Mg ii Lag Results from Four Years of Monitoring

Abstract: We present reverberation mapping results for the Mg ii λ2800 Å broad emission line in a sample of 193 quasars at 0.35 < z < 1.7 with photometric and spectroscopic monitoring observations from the Sloan Digital Sky Survey Reverberation Mapping project during 201… Show more

Cited by 81 publications

References 100 publications

Microlensing of the broad emission lines in 27 gravitationally lensed quasars. Broad line region structure and kinematics

Microlensing of the broad emission lines in 27 gravitationally lensed quasars. Broad line region structure and kinematics

Microlensing of the broad emission lines in 27 gravitationally lensed quasars

The Sloan Digital Sky Survey Reverberation Mapping Project: Estimating Masses of Black Holes in Quasars with Single-epoch Spectroscopy

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