Luminosity Function of High-Mass X-ray Binaries and Anisotropy in the Distribution of Active Galactic Nuclei toward the Large Magellanic Cloud

TL;DR

This study analyzes the luminosity function of high-mass X-ray binaries and the anisotropic distribution of active galactic nuclei toward the Large Magellanic Cloud using deep X-ray survey data, revealing a power-law luminosity function and nonuniform matter distribution.

Contribution

It provides the first detailed statistical analysis of high-mass X-ray binaries and AGNs in the LMC direction, highlighting the luminosity function and matter distribution anisotropy.

Findings

The luminosity function follows a power law with slope ~1.8.

Fewer AGNs are observed toward the LMC compared to other directions.

The distribution of matter in the local Universe is nonuniform.

Abstract

In 2003-2012, the INTEGRAL observatory has performed long-term observations of the Large Magellanic Cloud (LMC). At present, this is one of the deepest hard X-ray (20-60 keV) surveys of extragalactic fields in which more than 20 sources of different natures have been detected. We present the results of a statistical analysis of the population of high-mass X-ray binaries in the LMC and active galactic nuclei (AGNs) observed in its direction. The hard X-ray luminosity function of high-mass X-ray binaries is shown to be described by a power law with a slope alpha~1.8, that in agreement with the luminosity function measurements both in the LMC itself, but made in the soft X-ray energy band, and in other galaxies. At the same time, the number of detected AGNs toward the LMC turns out to be considerably smaller than the number of AGNs registered in other directions, in particular, toward the source 3C 273. The latter confirms the previously made assumption that the distribution of matter in the local Universe is nonuniform.