BlackCAT: A catalogue of stellar-mass black holes in X-ray transients

Abstract

Aims. During the last ∼50 years, the population of black hole candidates in X-ray binaries has increased considerably, with 59 Galactic objects being detected in transient low-mass X-ray binaries, as well as a few in persistent systems (including ∼5 extragalactic binaries). Methods. We collect near-infrared, optical, and X-ray information spread over hundreds of references to study the population of black holes in X-ray transients as a whole.Results. We present the most updated catalogue of black hole transients. This contains X-ray, optical, and near-infrared observations, together with their astrometric and dynamical properties. The catalogue provides new and useful information in both statistical and observational parameters and provides a thorough and complete overview of the black hole population in the Milky Way. Analysing the distances and spatial distribution of the observed systems, we estimate a total population of ∼1300 Galactic black hole transients. This means that we have only discovered less than ∼5% of the total Galactic distribution.

Black hole mass function from gravitational wave measurements

“…To this day, only 29 such BHs have been detected. These include 23 BHs discovered through X-rays, 18 of which are galactic (see [17,40,41] and references therein) and five extragalactic [18,[42][43][44][45][46]. The remaining ones were recently detected through the gravitational waves released from the merger of BBHs with masses between 7 to 36 M into even more massive end products (in total six premerger BHs in three merger events) [29][30][31].…”

“…The remaining ones were recently detected through the gravitational waves released from the merger of BBHs with masses between 7 to 36 M into even more massive end products (in total six premerger BHs in three merger events) [29][30][31]. In addition, there are 42 X-ray transients within the Milky Way that are candidates for hosting BHs [17].…”

“…To date, less than two dozen stellar-mass BHs have been detected in this way, most of them in the Milky Way, with a handful of extragalactic candidates [17,18]. These X-ray observations, however, are limited in reach, becoming more biased as the distance from Earth grows, and do not allow a meaningful sample to be gathered in order to test the black hole mass function (BHMF) on cosmological scales.…”

Polarized synchrotron emission in quiescent black hole X-ray transients

“…The data were de-reddened using extinction values of Av = 1.05 for A0620-00 and Av = 0.124 for Swift J1357.2-0933 (Cantrell et al 2010;Armas Padilla et al 2013;Corral-Santana et al 2016), adopting the extinction law of Cardelli, Clayton & Mathis (1989). We note that using other dust extinction laws in the infrared (Indebetouw et al 2005;Chiar & Tielens 2006) would change the J, H, KS fluxes by < 3 per cent and < 0.3 per cent for A0620-00 and Swift J1357.2-0933 respectively, and so do not significantly alter their spectrum in Fig.…”

Simultaneous optical/X-ray study of GS 1354-64 (=BW Cir) during hard outburst: evidence for optical cyclo-synchrotron emission from the hot accretion flow

“…Swift/XRT X-ray spectrum on 10 June 2015 can be fitted with a power-law photon index of 1.5 ± 0.1 (Miller et al 2015b). Using the SOAR Optical Imager (SOI) at Cerro Pachon, Chile, Corral-Santana et al (2015) measured the g', r' and i' magnitudes to be ∼19.76, ∼18.49, ∼18.34 respectively on 10-11 June 2015. The detailed evolution of the 2015 outburst in GS 1354-64 at optical, UV and X-ray bands has been presented by Koljonen et al (2016).…”