Optical spectral index - luminosity relation for the 17 mapped Palomar-Green quasars

Abstract

In this paper, the optical spectra index - luminosity relationship is checked for the well-known 17 individual mapped QSOs, in order to give one more clearer conclusion on the so far conflicting dependence of the spectral index on the luminosity for AGN. Different from the global relationships based on the color difference (photometry parameters) for samples of AGN, the more reliable relationship is determined for the multi-epoch observed individual mapped QSOs with no contamination from the host galaxies, the line variabilities and the much different central properties. The final confirmed results are as follows. (1): No strong dependence of the optical spectral index on the continuum luminosity can be found for all the 17 QSOs, besides two objects (PG 0026 and PG 1613) having some weak trends (with $3\sigma$ confidence level) for the relationship. In other words, the common sense 'AGNs get bluer when they get brighter' is not so common. (2): There are much different damped intrinsic variability time scales for the variability modes of the optical spectral index and the continuum emission, through the well applied Damped Random Walk method for the AGN variability. In other words, there are some different intrinsic mechanisms controlling the variabilities of the optical spectral index and the power law AGN continuum emission. Therefore, the much weak dependence of the optical spectral index on the continuum luminosity can be further confirmed.

12 pages, 7 figures, Accepted and to be published in MNRAS

References in corpus (14)

• Modeling the Time Variability of SDSS Stripe 82 Quasars as a Damped Random Walk
• The Radius-Luminosity Relationship for Active Galactic Nuclei: The Effect of Host-Galaxy Starlight on Luminosity Measurements
• Is Quasar Optical Variability a Damped Random Walk?
• 3d dualities from 4d dualities for orthogonal groups
• On the variability of quasars: a link between Eddington ratio and optical variability?
• The Mass of the Black Hole in the Seyfert 1 Galaxy NGC 4593 from Reverberation Mapping
• The dependence of quasar variability on black hole mass
• Assessment of stochastic and deterministic models of 6304 quasar lightcurves from SDSS Stripe 82
• A Bayesian method for the analysis of deterministic and stochastic time series
• Is the dependence of spectral index on luminosity real in optically selected AGN samples?
• Further Evidence for the Accretion Disk Origination of the Double-Peaked Broad H$\alpha$ of 3C390.3
• The relation between the optical spectral slope and the luminosity for 17 Palomar-Green QSOs
• The Correlation Between Spectral Index And Accretion Rate For AGN
• More Evidence for the Intermediate Broad Line Region of the Mapped AGN PG 0052+251

Cited by in corpus (4)

• Supermassive Black Holes with High Accretion Rates in Active Galactic Nuclei. III. Detection of Fe II Reverberation in Nine Narrow-Line Seyfert 1 Galaxies
• Statistical Properties of Multi-epoch Spectral Variability of SDSS Stripe82 Quasars
• A catalog of optical to X-ray spectral energy distributions of z~2 quasars observed with Swift. I: First results
• Extreme Variability Quasars in Their Various States. II: Spectral Variation Revealed with Multi-epoch Spectra