A rapid and dramatic outburst in Blazar 3C 454.3 during May 2005 - Optical and infrared observations with REM and AIT

TL;DR

This paper reports on optical and infrared observations of the highly active blazar 3C 454.3 during a significant outburst in 2005, revealing a historical high state and insights into its spectral behavior and variability mechanisms.

Contribution

First near-IR/optical photometry during the 2005 outburst, providing detailed temporal and spectral data on the blazar's high activity state.

Findings

Observed a historical high state with brightness decrease over 86 days

Spectral analysis suggests a synchrotron peak below near-IR band

Variability likely due to geometrical changes in beaming direction

Abstract

The flat-spectrum radio quasar 3C 454.3 is well known to be a highly active and variable source with outbursts occurring across the whole electromagnetic spectrum over the last decades. In spring 2005, 3C 454.3 has been reported to exhibit a strong optical outburst which subsequently triggered multi-frequency observations of the source covering the radio up to gamma-ray bands. Here, we present first results of our near-IR/optical (V, R, I, H band) photometry performed between May 11 and August 5, 2005 with the Rapid Eye Mount (REM) at La Silla in Chile and the Automatic Imaging Telescope (AIT) of the Perugia University Observatory. 3C 454.3 was observed during an exceptional and historical high state with a subsequent decrease in brightness over our 86 days observing period. The continuum spectral behaviour during the flaring and declining phase suggests a synchrotron peak below the near-IR band as well as a geometrical origin of the variations e.g. due to changes in the direction of forward beaming.