The 2010 May Flaring Episode of Cygnus X-3 in Radio, X-Rays, and {\gamma}-Rays

TL;DR

This paper presents multi-wavelength observations of Cygnus X-3 during a 2010 flare, revealing a sequence of X-ray, radio, and gamma-ray emissions that challenge existing models of gamma-ray production in microquasars.

Contribution

It provides detailed temporal data across radio, X-ray, and gamma-ray bands during a flare, offering new insights into the emission mechanisms of Cygnus X-3.

Findings

Gamma-ray flare occurred ~1.5 days after radio flare.

X-ray emission softened and recovered over ~3 days.

Sequence of events challenges inverse Compton scattering models.

Abstract

In 2009, Cygnus X-3 (Cyg X-3) became the first microquasar to be detected in the GeV {\gamma}-ray regime, via the satellites Fermi and AGILE. The addition of this new band to the observational toolbox holds promise for building a more detailed understanding of the relativistic jets of this and other systems. We present a rich dataset of radio, hard and soft X-ray, and {\gamma}-ray observations of Cyg X-3 made during a flaring episode in 2010 May. We detect a ~3-d softening and recovery of the X-ray emission, followed almost immediately by a ~1-Jy radio flare at 15 GHz, followed by a 4.3{\sigma} {\gamma}-ray flare (E > 100 MeV) ~1.5 d later. The radio sampling is sparse, but we use archival data to argue that it is unlikely the {\gamma}-ray flare was followed by any significant unobserved radio flares. In this case, the sequencing of the observed events is difficult to explain in a model in which the {\gamma}-ray emission is due to inverse Compton scattering of the companion star's radiation field. Our observations suggest that other mechanisms may also be responsible for {\gamma}-ray emission from Cyg X-3.