Calibrating C-Iv-Based Black Hole Mass Estimators

Park, Daeseong; Woo, Jong-Hak; Denney, K. D.; Shin, Jaejin

doi:10.1088/0004-637x/770/2/87

Cited by 82 publications

(133 citation statements)

References 69 publications

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“…12 The radius of the corona has been fixed to 20 Rg, instead of 8 as in AD1. Shen et al 2008;Park et al 2013, but see also Trakhtenbrot & Netzer 2012).…”

Section: Agn Accretion Disc Modelsmentioning

confidence: 99%

The first ultraviolet quasar-stacked spectrum at z ≃ 2.4 from WFC3

Lusso

Worseck

Hennawi

et al. 2015

Monthly Notices of the Royal Astronomical Society

273

355

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The ionising continuum from active galactic nuclei (AGN) is fundamental for interpreting their broad emission lines and understanding their impact on the surrounding gas. Furthermore, it provides hints on how matter accretes onto supermassive black holes. Using HST's Wide Field Camera 3 we have constructed the first stacked ultraviolet (rest-frame wavelengths 600-2500Å) spectrum of 53 luminous quasars at z 2.4, with a state-of-the-art correction for the intervening Lyman forest and Lyman continuum absorption. The continuum slope (f ν ∝ ν αν ) of the full sample shows a break at ∼912Å with spectral index α ν = −0.61 ± 0.01 at λ > 912Å and a softening at shorter wavelengths (α ν = −1.70 ± 0.61 at λ 912Å). Our analysis proves that a proper intergalactic medium absorption correction is required to establish the intrinsic continuum emission of quasars. We interpret our average ultraviolet spectrum in the context of photoionisation, accretion disk models, and quasar contribution to the ultraviolet background. We find that observed broad line ratios are consistent with those predicted assuming an ionising slope of α ion =−2.0, similar to the observed ionising spectrum in the same wavelength range. The continuum break and softening are consistent with accretion disk plus X-ray corona models when black hole spin is taken into account. Our spectral energy distribution yields a 30% increase to previous estimates of the specific quasar emissivity, such that quasars may contribute significantly to the total specific Lyman limit emissivity estimated from the Lyα forest at z < 3.2.

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“…12 The radius of the corona has been fixed to 20 Rg, instead of 8 as in AD1. Shen et al 2008;Park et al 2013, but see also Trakhtenbrot & Netzer 2012).…”

Section: Agn Accretion Disc Modelsmentioning

confidence: 99%

The first ultraviolet quasar-stacked spectrum at z ≃ 2.4 from WFC3

Lusso

Worseck

Hennawi

et al. 2015

Monthly Notices of the Royal Astronomical Society

273

355

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“…We did not subtract a narrow C iv from the line profile because it is still debated as to whether a narrow C iv component is present (Wills et al 1993;Marziani et al 1996;Sulentic et al 2007), and to be comparable with other studies (e.g.,VP06, S11, Assef et al 2011;Park et al 2013). For the same reason, we also did not fit the 1600 Å feature (Laor et al 1994;Fine et al 2010).…”

Section: IVmentioning

confidence: 99%

Mid-Infrared-Selected Quasars. I. Virial Black Hole Mass and Eddington Ratios

Dai

Elvis

Bergeron

et al. 2014

ApJ

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We provide a catalog of 391 mid-infrared-selected (MIR; 24 μm) broad-emission-line (BEL; type 1) quasars in the 22 deg 2 SWIRE Lockman Hole field. This quasar sample is selected in the MIR from Spitzer MIPS with S 24 > 400 μJy, jointly with an optical magnitude limit of r (AB) < 22.5 for broad line identification. The catalog is based on MMT and Sloan Digital Sky Survey (SDSS) spectroscopy to select BEL quasars, extending the SDSS coverage to fainter magnitudes and lower redshifts, and recovers a more complete quasar population. The MIR-selected quasar sample peaks at z ∼ 1.4 and recovers a significant and constant (20%) fraction of extended objects with SDSS photometry across magnitudes, which were not included in the SDSS quasar survey dominated by point sources. This sample also recovers a significant population of z < 3 quasars at i > 19.1. We then investigate the continuum luminosity and line profiles of these MIR quasars, and estimate their virial black hole masses and the Eddington ratios. The supermassive black hole mass shows evidence of downsizing, although the Eddington ratios remain constant at 1 < z < 4. Compared to point sources in the same redshift range, extended sources at z < 1 show systematically lower Eddington ratios. The catalog and spectra are publicly available online.

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“…j Mass estimated from Hβ profile in Marziani et al (2003a), using the formula of Assef (2011). k Mass estimated from the SDSS C IV profile using the formula of Park et al (2013). Figure 1.…”

Section: Hst Observationsmentioning

confidence: 99%

“…This is appropriate since the BOSS observations were designed to increase signal-to-noise at the blue end of the spectra at the expense of an accurate absolute flux calibration. Column (9) is M bh estimated from the C IV broad emission line in the SDSS spectrum (Park et al 2013). Each individual measurement has about 0.3 dex uncertainty (Park et al 2013).…”

Section: Sdss Extreme Ultraviolet Variability Datamentioning

confidence: 99%

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The Extreme Ultraviolet Variability of Quasars

Punsly

Marziani

Zhang

et al. 2016

ApJ

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We study the extreme ultraviolet (EUV) variability (rest frame wavelengths 500-920 Å) of high-luminosity quasars using Hubble Space Telescope (HST) (low to intermediate redshift sample) and Sloan Digital sky Survey (SDSS) (high redshift sample) archives. The combined HST and SDSS data indicates a much more pronounced variability when the sampling time between observations in the quasar rest frame is >2 10 s 7 compared to <1.5 10 7 s. Based on an excess variance analysis, for time intervals <2 10 s 7 in the quasar rest frame, 10% of the quasars (4/40) show evidence of EUV variability. Similarly, for time intervals >2 10 s 7 in the quasar rest frame, 55% of the quasars (21/38) show evidence of EUV variability. The propensity for variability does not show any statistically significant change between2.5 10 s 7 and3.16 10 s 7 (1 year). The temporal behavior is one of a threshold time interval for significant variability as opposed to a gradual increase on these timescales. A threshold timescale can indicate a characteristic spatial dimension of the EUV region. We explore this concept in the context of the slim disk models of accretion. We find that for rapidly spinning black holes, the radial infall time to the plunge region of the optically thin surface layer of the slim disk that is responsible for the preponderance of the EUV flux emission (primarily within 0-7 black hole radii from the inner edge of the disk) is consistent with the empirically determined variability timescale.

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Calibrating C-Iv-Based Black Hole Mass Estimators

Cited by 82 publications

References 69 publications

The first ultraviolet quasar-stacked spectrum at z ≃ 2.4 from WFC3

The first ultraviolet quasar-stacked spectrum at z ≃ 2.4 from WFC3

Mid-Infrared-Selected Quasars. I. Virial Black Hole Mass and Eddington Ratios

The Extreme Ultraviolet Variability of Quasars

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