Optical Monitoring of 3C 390.3 from 1995 to 2004 and Possible Periodicities in the Historical Light Curve

TL;DR

This study presents optical photometry data of the radio galaxy 3C 390.3 over nearly a decade, constructs a historical light curve spanning over a century, and identifies potential periodicities in its brightness variations.

Contribution

It combines new observational data with historical records to analyze long-term variability and suggests possible periodic cycles in the galaxy's light curve.

Findings

Identified potential periodicities of approximately 8.3, 5.4, 3.5, and 2.1 years.

Constructed a comprehensive light curve from 1894 to 2004.

Detected possible cyclic behavior in the galaxy's brightness.

Abstract

We report V, R, and I band CCD photometry of the radio galaxy 3C 390.3 obtained with the 1.56-m telescope of the Shanghai Astronomical Observatory from March 1995 to August 2004. Combining these data with data from the literature, we have constructed a historical light curve from 1894 to 2004 and searched for periodicities using the CLEANest program. We find possible periods of 8.30+-1.17, 5.37+-0.49, 3.51+-0.21, and 2.13+-0.08 years.