Related papers: Radio Emission from the Be/Black Hole Binary MWC 6…

We report the discovery of a candidate stellar-mass black hole in the Milky Way globular cluster M62. We detected the black hole candidate, which we term M62-VLA1, in the core of the cluster using deep radio continuum imaging from the Karl…

We report the results of a long-term spectroscopic monitoring of the FS\,CMa type object MWC\,728. We found that it is a binary system with a B5 Ve (T$_{\rm eff}$ = 14000$\pm$1000 K) primary and a G8 III type (T$_{\rm eff} \sim$ 5000 K)…

The coalescence of massive black hole (BH) binaries due to galaxy mergers provides a primary source of low-frequency gravitational radiation detectable by pulsar timing measurements and by the proposed LISA (Laser Interferometry Space…

The origin of the high X-ray luminosities of most ultraluminous X-ray sources (ULXs) still remains poorly understood. Most of the scenarios proposed to explain their nature assume that ULXs are powered by accretion on to a black hole (BH).…

Binary systems consisting of an early type star and a black hole (BH) are crucial for understanding various astrophysical phenomena, particularly the origins of detected gravitational wave sources. Be binary systems are expected to…

With the purpose to investigate the radio emission of new ultracool objects, we carried out a targeted search in the recently discovered system VHS J125601.92$-$125723.9 (hereafter VHS 1256$-$1257); this system is composed by an equal-mass…

[abridged] The radio:X-ray correlation for hard and quiescent state black hole X-ray binaries is critically investigated in this paper. New observations of known sources, along with newly discovered ones, have resulted in an increasingly…

We present a multi-wavelength analysis, from the radio to the X-ray band, of the redshift $z=6.44$ VIK J2318$-$31 radio-loud (RL) quasi stellar object (QSO), one of the most distant currently known in this class. The work is based on newly…

We studied the relation of accretion-jet power and disk luminosity, especially the jet efficiencies and disk radiative efficiencies for different accretion disks as well as black hole (BH) spin, in order to explore the origin of radio…

Based on high-resolution ultraviolet spectroscopy obtained with FUSE and COS, we present new detections of O VI and N V emission from the black-hole X-ray binary (XRB) system LMC X-3. We also update the ephemeris of the XRB using recent…

We present evidence for a broad, ionized Fe K line in the XMM-Newton spectrum of the broad-line radio galaxy (BLRG) 4C+74.26. This is the first indication that the innermost regions of the accretion flow in BLRGs contain thin, radiatively…

Polarimetry provides an avenue for probing the geometry and physical mechanisms producing optical radiation in many astrophysical objects, including stellar binary systems. We present the results of multiwavelength (BVR) polarimetric…

Observations of some quiescent black hole X-ray binaries have revealed an excess of mid-infrared (MIR) emission above that expected from their donor stars. In one system, V404 Cygni, this excess has been variously suggested to arise from…

We examine the disc--jet connection in stellar mass and supermassive black holes by investigating the properties of their compact emission in the hard X-ray and radio bands. We compile a sample of ~100 active galactic nuclei with measured…

We present a comprehensive study of (quasi-)simultaneous radio:X-ray observations of stellar black hole binaries during the spectrally hard X-ray state, finding evidence for a strong correlation between these two bands over more than three…

We report on the analysis of new and previously published MMT optical spectra of the black hole binary XTE J1118+480 during the decline from the 2000 outburst to true quiescence. From cross-correlation with template stars, we measure the…

The few known gamma-ray binary systems are all associated with variable radio and X-ray emission. The TeV source HESS J0632+057, apparently associated with the Be star MWC148, is plausibly a new member of this class. Following the…

We present results from multi-wavelength simultaneous X-ray and radio observations of the black hole X-ray binary V404 Cyg in quiescence. Our coverage with NuSTAR provides the very first opportunity to study the X-ray spectrum of V404 Cyg…

MAXI J1535-571 is a Galactic black hole candidate X-ray binary that was discovered going into outburst in 2017 September. In this paper, we present comprehensive radio monitoring of this system using the Australia Telescope Compact Array…

We obtained multi-epoch Very Large Telescope (VLT) optical spectroscopic data in 2011 and 2012 on the ultraluminous X-ray source (ULX) NGC 5408 X-1. We confirm that the HeII\lambda4686 line has a broad component with an average FWHM of…