Estimating Black Hole Masses in Active Galaxies Using the Hα Emission Line

Greene, Jenny E.; Ho, Luis C.

doi:10.1086/431897

Cited by 703 publications

(897 citation statements)

References 58 publications

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“…2 and Table 1, we found that the line-intensity ratio of [O III]λ5007 to the narrow Hβ is 9.6± 3.8, which is consistent with the universal adopted value of 10 from the photoionization model for NLRs clouds. Considering the errors of the linewidth, the FWHM of the narrow Hβ line is consistent with that of FWHM of the narrow and broad [O III] (Grupe et al 1998;Grupe et al 1999;Grupe et al 2004;Greene & Ho, 2005a;2005b …”

Section: Data and Analysissupporting

confidence: 72%

SDSS J143030.22–001115.1: A Misclassified Narrow-line Seyfert 1 Galaxy with Flat X-ray Spectrum

Bian

Qian

Chao

2006

Chin. J. Astron. Astrophys.

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Section: Data and Analysissupporting

confidence: 72%

SDSS J143030.22–001115.1: A Misclassified Narrow-line Seyfert 1 Galaxy with Flat X-ray Spectrum

Bian

Qian

Chao

2006

Chin. J. Astron. Astrophys.

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“…However, based on the data sets of Stern & Laor (2012), the Greene & Ho (2005) relation overestimated the luminosity of the broad Hα component for L 5100 Å <∼ 4 × 10 43 erg s −1 and the luminosity at 5100 Å for our sample is mainly below this threshold.…”

Section: Discussionmentioning

confidence: 51%

“…We found that the expected luminosity of the broad Hα line predicted by L 5100 Å (relation from Greene & Ho 2005) is up to 10 times larger than the luminosity predicted by L 2 kev (relation from Stern & Laor 2012). This leads to a larger number of sources with L UpLim,bHα < L exp,bHα from L 5100 Å (91% of the unobscured Sy2 sample) that from L 2 kev (21%).…”

Section: Discussionmentioning

confidence: 69%

“…10 of Stern & Laor (2012) (L 5100 Å vs. L b,Hα ), the relation from Greene & Ho (2005) does not fit the type-1 SDSS sample of Stern & Laor (2012) for low 5100 Å luminosity (L 5100 Å < ∼ 4 × 10 43 erg s −1 ) and overestimates the broad Hα luminosity compared with what is observed. As most (about 70%) of our unobscured Sy2 have L 5100 Å < 4 × 10 43 erg s −1 , it may explain why L b,Hα (L 5100 Å ) > L b,Hα (L 2 keV ).…”

Section: The Expected Broad Lines and The Quality Of The Optical Spectramentioning

confidence: 72%

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A new sample of X-ray selected narrow emission-line galaxies

Pons

Watson

2016

A&A

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A sample of X-ray and optically selected narrow emission-line galaxies (769 sources) from the 3XMM catalogue cross-correlated with SDSS (DR9) catalogue has been studied. Narrow-emission line active galactic nuclei (AGN; type-2) have been selected on the basis of their emission line ratios and/or X-ray luminosity. We have looked for X-ray unobscured type-2 AGN. As X-ray spectra were not available for our whole sample, we have checked the reliability of using the X-ray hardness ratio (HR) as a probe of the level of obscuration and we found a very good agreement with full spectral fitting results, with only 2% of the sources with apparently unobscured HR turning out to have an obscured spectrum. Despite the fact that type-2 AGN are supposed to be absorbed based on the Unified Model, about 60% of them show no sign or very low level of X-ray obscuration. After subtraction of contaminants to the sample, that is Narrow-Line Seyfert 1 and Compton-thick AGN, the fraction of unobscured Sy2 drops to 47%. For these sources, we were able to rule out dust reddening and variability for most of them as an explanation of the absence of optical broad emission-lines. The main explanations remaining are the dilution of weak/very broad emission-lines by the host galaxy and the intrinsic absence of the broad-line region (BLR) due to low accretion rates (i.e. True Sy2). However, the number of True Sy2 strongly depends on the method used to verify the intrinsic lack of broad lines. Indeed using the optical continuum luminosity to predict the BLR properties gives a much larger fraction of True Sy2 (about 90% of the unobscured Sy2 sample) than the use of the X-ray 2 keV luminosity (about 20%). Nevertheless the number of AGN we securely detected as True Sy2 is at least three times larger that the previously confirmed number of True Sy2.

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“…RM requires extensive long-term monitoring programmes, and is thus very expensive observationally; however, it has allowed the calibration of BH mass estimates from single-epoch observations of the broad emission lines in AGN optical spectra (e.g. Woo & Urry 2002;Greene & Ho 2005;Matsuoka et al 2013). The abundance of suitable single epoch spectra means that this method has now been applied to a great many AGN, generally utilizing the well-studied Balmer-series hydrogen lines Hα and Hβ.…”

Section: Black Hole Mass Estimatesmentioning

confidence: 99%

Reaching the peak of the quasar spectral energy distribution – I. Observations and models

Collinson

Ward

Done

et al. 2015

Monthly Notices of the Royal Astronomical Society

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We perform a spectral analysis of a sample of 11 medium redshift (1.5 z 2.2) quasars. Our sample all have optical spectra from the SDSS, infrared spectra from GNIRS and TSPEC, and X-ray spectra from XMM-Newton. We first analyse the Balmer broad emission line profiles which are shifted into the IR spectra to constrain black hole masses. Then we fit an energy-conserving, three component accretion model of the broadband spectral energy distribution (SED) to our multiwavelength data. Five out of the 11 quasars show evidence of an SED peak, allowing us to constrain their bolometric luminosity from these models and estimate their mass accretion rates. Based on our limited sample, we suggest that estimating bolometric luminosities from L 5100 Å and L 2−10 keV may be unreliable, as has been also noted for a low-redshift, X-ray selected AGN sample.

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Estimating Black Hole Masses in Active Galaxies Using the Hα Emission Line

Cited by 703 publications

References 58 publications

SDSS J143030.22–001115.1: A Misclassified Narrow-line Seyfert 1 Galaxy with Flat X-ray Spectrum

SDSS J143030.22–001115.1: A Misclassified Narrow-line Seyfert 1 Galaxy with Flat X-ray Spectrum

A new sample of X-ray selected narrow emission-line galaxies

Reaching the peak of the quasar spectral energy distribution – I. Observations and models

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