INTEGRAL serendipitous observations of solar and terrestrial X-rays and gamma rays

TL;DR

INTEGRAL space mission, despite operational constraints, serendipitously detected solar flares, auroral X-ray emissions, and Earth's radiation belts, providing new insights into solar-terrestrial phenomena.

Contribution

First presentation of auroral X-ray observations by INTEGRAL and review of intense solar flare detections and Earth's radiation belt studies using serendipitous data.

Findings

Detected strong auroral X-ray emissions from Earth.

Observed intense solar flares outside the main field of view.

Reviewed Earth's radiation belt phenomena with INTEGRAL data.

Abstract

ESA's INTEGRAL space mission has achieved unique results for solar and terrestrial physics, although spacecraft operations nominally excluded the possibility to point at the Sun or the Earth. The Earth avoidance was, however, exceptionally relaxed for special occultation observations of the Cosmic X-ray Background (CXB), which on some occasions allowed the detection of strong X-ray auroral emission. In addition, the most intense solar flares can be bright enough to be detectable from outside the field of view of the main instruments. This article presents for the first time the auroral observations by INTEGRAL and reviews earlier studies of the most intense solar flares. We end by briefly summarising the studies of the Earth's radiation belts, which can be considered as another topic of serendipitous science with INTEGRAL.