Multi-wavelength Observations of LS I +61 303 with VERITAS, Swift and RXT E: 2006-2008

TL;DR

This study presents a comprehensive multi-wavelength monitoring of LS I +61 303, revealing its variable TeV and X-ray emissions, with significant flaring activity and flux variability, but no clear correlation between TeV and X-ray data.

Contribution

First long-term multi-wavelength campaign combining TeV, X-ray, and optical observations of LS I +61 303, providing new insights into its variability and flaring behavior.

Findings

Detected variable TeV emission with flux 5-20% of Crab Nebula.

Observed highly variable X-ray flux with large flaring episodes.

No clear correlation found between TeV and X-ray emissions.

Abstract

A long term, multi-wavelength monitoring campaign on the TeV binary LS I +61 303 has been performed utilizing >300 GeV observations with VERITAS along with monitoring in the 0.2-10 keV band by RXTE and Swift between September 2006 and February 2008. The source was detected by VERITAS as a variable TeV source with flux values ranging from 5-20% of the Crab Nebula flux with the strongest flux levels appearing around apastron. X-ray observations by RXTE and Swift show the source as a highly variable hard X-ray source with flux values varying in the range of 0.5-3*10^-11 ergs cm^-2 s^-1 over a single orbital cycle. The 2007-2008 RXTE data set also shows the presence of several extremely large flaring episodes presenting a flux of up to 7.2*10^-11 ergs cm^-2 s^-1, the largest such flare recorded from this source. Comparison of the contemporaneous TeV and X-ray data does not show a correlation at this time, however, the sparsity of data sets do not preclude the existence of such a correlation.