15 years of Galactic surveys and hard X-ray Background measurements

TL;DR

Over 15 years, INTEGRAL has extensively surveyed the Galactic plane in hard X-rays, enabling the detection of transient sources and detailed measurements of the cosmic X-ray background, significantly advancing high-energy astrophysics.

Contribution

This paper reviews the long-term INTEGRAL survey efforts, highlighting its unique capabilities and key contributions to understanding the hard X-ray sky and cosmic background.

Findings

Comprehensive cataloging of hard X-ray sources in the Milky Way.

Detection of transient X-ray emitters across various timescales.

Measurement of the large-scale cosmic X-ray background.

Abstract

The INTEGRAL hard X-ray surveys have proven to be of fundamental importance. INTEGRAL has mapped the Galactic plane with its large field of view and excellent sensitivity. Such hard X-ray snapshots of the whole Milky Way on a time scale of a year are beyond the capabilities of past and current narrow-FOV grazing incidence X-ray telescopes. By expanding the INTEGRAL X-ray survey into shorter timescales, a productive search for transient X-ray emitters was made possible. In more than fifteen years of operation, the INTEGRAL observatory has given us a sharper view of the hard X-ray sky, and provided the triggers for many follow-up campaigns from radio frequencies to gamma-rays. In addition to conducting a census of hard X-ray sources across the entire sky, INTEGRAL has carried out, through Earth occultation maneuvers, unique observations of the large-scale cosmic X-ray background, which will without question be included in the annals of X-ray astronomy as one of the mission's most salient contribution to our understanding of the hard X-ray sky.