30 Years of Multifrequency Quasar Variability: A Personal Journey

James R Webb

doi:10.3390/galaxies9040069

Abstract

I outline the history of and progress in observing and understanding quasar multi-frequency and multi-messenger variability from the point of view of someone who has been working in the field for over 30 years. I will present some important references for the evolution from optical monitoring to multi-frequency cooperative programs that revealed the true multi-frequency/multi-timescale nature of variability in these objects. Quasar observations began with separate radio and optical monitoring programs; then the optical and radio observations w ere combined. This was followed by expanding the analyses to include far IR, UV, X-rays, and finally adding gamma rays. This progression yielded simultaneous multi-frequency spectra of these objects and light curves over 15 decades in frequency. The future is adding particle (neutrino) and gravitational waves to the picture. I also present long-term (50 years) optical light curves, and discuss optical variability at all timescales from minutes to tens of years in some selected objects for which we have reliable long-term monitoring observations.

Highlights

My introduction to quasars began as an undergraduate physics major interested in astronomy
Guiding was done by staring into a small guide scope and using a hand-paddle for real-time manual input of tracking corrections as the guide star drifted from the cross hairs in the guide scope
I have continued monitoring my list of Blazars using the Southeastern Association for Research in Astronomy (SARA) telescopes and the Stocker telescope and concentrated on studying the rapid intraday or micro-variability of a few very active objects

Summary

Introduction

My introduction to quasars began as an undergraduate physics major interested in astronomy. I graduated with a Bachelor’s degree in physics and minor in astronomy (1981), applied and was accepted for graduate school at the University of Florida and began observing quasars as part of Dr Smith’s NSF supported research program using the technology of the time to monitor quasar optical variability: Photographic photometry. Data collected in this manner showed that were there several magnitudes of variability over long periods of time, and optical outbursts of several magnitudes over days and weeks [5,6].

Results

Conclusion