Empirical Conversions of Broad-Band Optical and Infrared Magnitudes to Monochromatic Continuum Luminosities for Active Galactic Nuclei

TL;DR

This study derives empirical relationships between broad-band optical/infrared magnitudes and monochromatic luminosities for a large quasar sample, aiding measurements of AGN properties when spectra are limited.

Contribution

It provides new, model-independent ratios linking broad-band magnitudes to monochromatic luminosities across a wide redshift range for quasars.

Findings

Ratios span z=0.1-4.9, enabling luminosity estimates.

Provides tabular and parametric forms of ratios.

Useful for estimating AGN properties without high-quality spectra.

Abstract

We use public data for 105783 quasars from The Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) that include spectral monochromatic luminosities at 5100\AA, 3000\AA, and 1350\AA, and the corresponding observed broad-band ugriz, VRI (converted), JHK and WISE magnitudes, and derive broad-band-to-monochromatic luminosity ratios independent of a cosmological model. The ratios span the redshift range of z=0.1-4.9 and may serve as a proxy for measuring the bolometric luminosity, broad line region (BLR) radii and/or black hole masses, whenever flux-calibrated spectra are unavailable or the existing spectra have low signal-to-noise ratios. They are provided both in tabular and parametric form.