The Galactic LMXB Population and the Galactic Centre Region

TL;DR

This paper reviews 17 years of INTEGRAL X-ray observations of the Milky Way, focusing on low-mass X-ray binaries, their distribution, physical phenomena, and recent activity of the Galactic Centre's supermassive black hole.

Contribution

It provides a comprehensive catalogue of 166 LMXBs detected by INTEGRAL and insights into their spatial distribution, physical phenomena, and the recent activity of Sgr A*.

Findings

Catalogue of 166 confirmed LMXBs from INTEGRAL data

Distribution of LMXBs across the Galaxy analyzed

Evidence of a major accretion episode of Sgr A* ~100 years ago

Abstract

Seventeen years of hard X-ray observations with the instruments of the INTEGRAL observatory, with a focus on the Milky Way and in particular on the Galactic Centre region, have provided a unique database for exploration of the Galactic population of low-mass X-ray binaries (LMXBs). Our understanding of the diverse energetic phenomena associated with accretion of matter onto neutron stars and black holes has greatly improved. We review the large variety of INTEGRAL based results related to LMXBs. In particular, we discuss the spatial distribution of LMXBs over the Galaxy and their X-ray luminosity function as well as various physical phenomena associated with Atoll and Z sources, bursters, symbiotic X-ray binaries, ultracompact X-ray binaries and persistent black hole LMXBs. We also present an up-to-date catalogue of confirmed LMXBs detected by INTEGRAL, which comprises 166 objects. Last but not least, the long-term monitoring of the Galactic Centre with INTEGRAL has shed light on the activity of Sgr A* in the recent past, confirming previous indications that our supermassive black hole experienced a major accretion episode just ~100 years ago. This exciting topic is covered in this review too.