Related papers: FIRST `Winged' and `X'-shaped Radio Source Candida…
Clusters of galaxies may contain cluster-wide, centrally located, diffuse radio sources, called halos. They have been found to show morphologies similar to those of the X-ray emission. To quantify this qualitative statement we performed a…
The observed relation between the X-ray and radio properties of low-luminosity accreting black holes has enabled the identification of multiple candidate black hole X-ray binaries (BHXBs) in globular clusters. Here we report an…
We have formed a new sample which consists of extended extragalactic radio sources without obvious active galactic nuclei (AGN) in them. Most of these sources appear to be dead double radio sources. These sources with steep spectra ($\alpha…
We present the scientific goals, the strategy and the first results of the REX project, an effort aimed at creating a sizable and statistically complete sample of Radio Emitting X-ray sources (REX) using the available data from a VLA survey…
The observations and theory of the exciting new class of galactic black hole X-ray transients is reviewed. Seven of these systems have measured mass functions or mass estimates in excess of stable neutron stars, making them excellent black…
Pulsar-black hole (BH) close binary systems, which have not been found yet, are unique laboratories for testing theories of gravity and understanding the formation channels of gravitational-wave sources. We study the self-gravitational…
The physical nature of ultraluminous x-ray sources is uncertain. Stellar mass black holes with beamed radiation and intermediate mass black holes with isotropic radiation are two plausible explanations. We discovered radio emission from an…
The radio source at the center of the cool core galaxy cluster RBS 797 (z=0.35) is known to exhibit a misalignment of its radio jets and lobes observed at different VLA-scale, with the innermost kpc-scale jets being almost orthogonal to the…
We do not fully understand the dynamics and evolution of a radio galaxy. Models of classical double (Type II) sources are in a reasonable state, but these objects are rare. Non-type II sources (generically called Type I) are far more…
From the LOFAR Two-metre Sky Survey second data release (LoTSS DR2) at 144 MHz, we identified a peculiar radio galaxy, J0011+3217. It has a large, one-sided diffuse secondary wing that stretches up to 0.85 Mpc (roughly 85\% of the size of…
Supermassive black hole binaries (SMBHBs) may exist in the centers of galaxies and active galactic nuclei (AGN) and are expected to be fairly common in the Universe as a consequence of merging processes between galaxies. The existence of…
Supermassive binary black holes (SBBHs) are a natural outcome of galaxy mergers. Here we show that low-frequency ($f \leq 10^{-6}$ Hz) quasi-periodic variability observed from cosmic blazar sources can provide substantial inductive support…
Radio observations discovered large scale non thermal sources in the central Mpc regions of dynamically disturbed galaxy clusters (radio halos). The morphological and spectral properties of these sources suggest that the emitting electrons…
I briefly review much of the X-ray and optical data on the nature of the ULXs in nearby galaxies. I present new results on radio emission, finding that the radio is usually rather luminous and extended. I review the X-ray data on timing and…
How Supermassive Blackholes (SMBHs) are spun-up is a key issue of modern astrophysics. As an extension of the study in Wang et al. (2016), we here address the issue by comparing the host galaxy properties of nearby ($z<0.05$) radio-selected…
In some clusters of galaxies, a diffuse non-thermal emission is present, not obviously associated with any individual galaxy. These sources have been identified as relics, mini-halos, and halos according to their properties and position…
We present the results of new observations of the enigmatic radio source B1144+352 with the WSRT at 1.4 GHz. The WENSS and NVSS surveys have revealed faint extended radio structures on Mpc-scales. We have investigated these large-scale…
We present the first broad-band X-ray study of the nuclei of 14 hard X-ray selected giant radio galaxies, based both on the literature and on the analysis of archival X-ray data from NuSTAR, XMM-Newton, Swift and INTEGRAL. The X-ray…
A small subset of extragalactic double radio sources, termed HYMORS (HYbrid MOrpholgy Radio Sources), is distinguished by a very unusual, hybrid morphology in terms of the Fanaroff-Riley (FR) classification. In HYMORS, one radio lobe…
Recent results on cluster cooling flows are reviewed. Observations of excess soft X-ray provides the only direct evidence for a major repository for the cooled gas. Unfortunately, the frequency of occurrence of large excess columns is…