Multifrequency Observations of the Optically Active Radio-quiet Quasar GQ Comae. II. Ultraviolet, Optical, and Infrared Continuum Variability

Abstract

This paper summarizes the data and preliminary results of a 3 yr long project to monitor the continuum variability of GQ Comae (PG 1202+281) from 0.12 microns to 3.5 microns. Substantial variability in the optical/ultraviolet flux was observed. The variability is examined using a geometrically thin accretion disk model. The model is able to reproduce the variations, but contains problems with physical consistency. A comparison of the optical/ultraviolet data and the infrared data indicates that the flux at 2.2 microns did not respond to the optical- ultraviolet continuum increase until nearly 250 days after the outburst and suggests that the variable flux at this wavelength is due to heated dust. We model the infrared emission with a dust component which is heated by the radiation from the accretion disk. We show that a simple model using a disklike distribution of heated dust grains can explain most of the infrared variability in a natural way.