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Open AccessJournal ArticleDOI

The Low-luminosity End of the Radius-Luminosity Relationship for Active Galactic Nuclei

TLDR
In this article, the authors present an updated and revised analysis of the relationship between the H{beta} broadline region (BLR) radius and the luminosity of the active galactic nucleus (AGN).
Abstract
We present an updated and revised analysis of the relationship between the H{beta} broad-line region (BLR) radius and the luminosity of the active galactic nucleus (AGN). Specifically, we have carried out two-dimensional surface brightness decompositions of the host galaxies of nine new AGNs imaged with the Hubble Space Telescope Wide Field Camera 3. The surface brightness decompositions allow us to create ''AGN-free'' images of the galaxies, from which we measure the starlight contribution to the optical luminosity measured through the ground-based spectroscopic aperture. We also incorporate 20 new reverberation-mapping measurements of the H{beta} time lag, which is assumed to yield the average H{beta} BLR radius. The final sample includes 41 AGNs covering four orders of magnitude in luminosity. The additions and updates incorporated here primarily affect the low-luminosity end of the R{sub BLR}-L relationship. The best fit to the relationship using a Bayesian analysis finds a slope of {alpha}= 0.533{sup +0.035}{sub -0.033}, consistent with previous work and with simple photoionization arguments. Only two AGNs appear to be outliers from the relationship, but both of them have monitoring light curves that raise doubt regarding the accuracy of their reported time lags. The scatter around the relationship is found to be 0.19more » {+-} 0.02 dex, but would be decreased to 0.13 dex by the removal of these two suspect measurements. A large fraction of the remaining scatter in the relationship is likely due to the inaccurate distances to the AGN host galaxies. Our results help support the possibility that the R{sub BLR}-L relationship could potentially be used to turn the BLRs of AGNs into standardizable candles. This would allow the cosmological expansion of the universe to be probed by a separate population of objects, and over a larger range of redshifts.« less

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Journal ArticleDOI

Discovery of a candidate inner Oort cloud planetoid

TL;DR: The most distant object ever seen in the solar system is the minor planet 2003 VB12 (popularly named Sedna) as mentioned in this paper, which has a semimajor axis of 480$\pm$40 AU and a perihelion of 76$ \pm$4AU.
Journal ArticleDOI

SALT long-slit spectroscopy of LBQS 2113-4538: variability of the Mg II and Fe II component

TL;DR: In this paper, the authors performed three spectroscopic observations of a quasar LBQS 2113-4538 (z = 0.956) with the SALT telescope, separated in time by several months and analyzed in detail the mean spectrum and the variability in the spectral shape.
Journal ArticleDOI

A new method to obtain the Broad Line Region size of high redshift quasars

TL;DR: In this paper, the authors present high S/N UV spectra for eight quasars at z ∼ 3 obtained with VLT/FORS. The spectra enable them to analyze in detail the strong and weak emission features in the rest-frame range 1300-2000 A of each source.
Journal ArticleDOI

Current and future applications of Reverberation-mapped quasars in Cosmology

TL;DR: In this article, the authors presented a recent MgII monitoring for the quasar CTS C30.10 with the Southern African Large Telescope (SALT) for which the cosmological constants, δm and δlambda, were determined.
References
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Journal ArticleDOI

Maps of Dust Infrared Emission for Use in Estimation of Reddening and Cosmic Microwave Background Radiation Foregrounds

TL;DR: In this article, a reprocessed composite of the COBE/DIRBE and IRAS/ISSA maps, with the zodiacal foreground and confirmed point sources removed, is presented.
Journal ArticleDOI

Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds

TL;DR: In this paper, the authors presented a reprocessed composite of the COBE/DIRBE and IRAS/ISSA maps, with the zodiacal foreground and confirmed point sources removed.
Book

Numerical Recipes in FORTRAN

TL;DR: The Diskette v 2.04, 3.5'' (720k) for IBM PC, PS/2 and compatibles [DOS] Reference Record created on 2004-09-07, modified on 2016-08-08.
Journal ArticleDOI

Measuring Reddening with Sloan Digital Sky Survey Stellar Spectra and Recalibrating SFD

TL;DR: In this paper, the authors measured the difference between the measured and predicted colors of a star, as derived from stellar parameters from the Sloan Extension for Galactic Understanding and Exploration Stellar Parameter Pipeline, and achieved uncertainties of 56, 34, 25, and 29 mmag in the colors u − g, g − r, r − i, and i − z, per star.
Journal ArticleDOI

Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD

TL;DR: Lee et al. as discussed by the authors measured the difference between the measured and predicted colors of a star, as derived from stellar parameters from the SEGUE Stellar Parameter Pipeline, and achieved uncertainties of 56, 34, 25, and 29 mmag in the colors u-g, g-r, r-i, and i-z, per star.
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