Related papers: A Black Hole Nova Obscured by an Inner Disk Torus
Time-resolved SALT spectra of the short-period, dipping X-ray transient, Swift J1357.2-0933, during its 2017 outburst has revealed broad Balmer and HeII4686 absorption features, blue-shifted by ~600 km/s. Remarkably these features are also…
We study a sample of $\sim$50,000 dwarf starburst and late-type galaxies drawn from the COSMOS survey with the aim of investigating the presence of nuclear accreting black holes (BHs) as those seed BHs from which supermassive BHs could grow…
We present X-ray properties of optically-selected intermediate-mass (~10^5--10^6 M_Sun) black holes (BHs) in active galaxies (AGNs), using data from the Chandra X-Ray Observatory. Our observations are a continuation of a pilot study by…
We consider radio emission from a newborn black hole (BH), which is accompanied by a mini-disk with a mass of $\lesssim M_\odot$. Such a disk can be formed from an outer edge of the progenitor's envelope, especially for metal-poor massive…
We propose a new type of electromagnetic transients associated with the birth of binary black holes (BBHs), which may lead to merger events accompanied by gravitational waves in $\sim0.1-1$ Gyr. We consider the newborn BBHs formed through…
We investigate the dependence of observational properties of black hole X-ray binaries on the inclination angle i of their orbits. We find the following: (1) Transient black hole binaries show no trend in their quiescent X-ray luminosities…
Black hole X-ray binaries are transient probably because their discs are subject to the same thermal-viscous instability which is present in dwarf nova binary systems. I discuss applications of the dwarf-nova instability model to transient,…
Swift J1357.2-0933 is the first confirmed very faint black hole X-ray transient and has a short estimated orbital period of 2.8 hr. We observed Swift J1357.2-0933 for ~50 ks with XMM-Newton in 2013 July during its quiescent state. The…
It is believed that stellar black holes (BHs) can be formed in two different ways: Either a massive star collapses directly into a BH without a supernova (SN) explosion, or an explosion occurs in a proto-neutron star, but the energy is too…
We report our multiwavelength study of the 2011 outburst evolution of the newly discovered black hole candidate X-ray binary Swift J1357.2-0933. We analysed the Swift X-ray telescope and Ultraviolet/Optical telescope (UVOT) data taken…
The new black hole transient Swift J1727.8--1613 exhibited a series of X-ray flares during its 2023 outburst extensively observed with Insight-HXMT. We analyze the spectra of the flaring period using a series of models consisting of a…
The defining characteristic of a black hole is that it possesses an event horizon through which matter and energy can fall in but from which nothing escapes. Soft X-ray transients (SXTs), a class of X-ray binaries, appear to confirm this…
We have discovered an accreting black hole (BH) in a spectroscopically confirmed globular cluster (GC) in NGC 1399 through monitoring of its X-ray activity. The source, with a peak luminosity of L_x=2x10^39 ergs/s, reveals an order of…
A significant number of stellar-mass black-hole (BH) binaries may merge in galactic nuclei or in the surrounding gas disks. With purposed space-borne gravitational-wave observatories, we may use such a binary as a signal carrier to probe…
Stellar-mass black holes have all been discovered through X-ray emission, which arises from the accretion of gas from their binary companions (this gas is either stripped from low-mass stars or supplied as winds from massive ones). Binary…
Swift J1753.5-0127 (J1753) is a candidate black hole low-mass X-ray binary (BH-LMXB) that was discovered in outburst in May 2005. It remained in outburst for $\sim12$ years, exhibiting a wide range of variability on various timescales,…
The black hole (BH) candidate SWIFT J1753.5-0127 has remained active since the onset of its 2005 outburst. Emission lines in the optical spectrum were observed at the very beginning of the outburst, but since then the spectrum has been…
Stellar-mass black holes are the final remnants of stars born with more than 15 solar masses. Billions are expected to reside in the Local Group, yet only few are known, mostly detected through X-rays emitted as they accrete material from a…
Flux variability is a remarkable property of black hole (BH) accreting systems, and a powerful tool to investigate the multi-scale structure of the accretion flow. The X-ray band is where some of the most rapid variations occur, pointing to…
When the mass accretion rate onto a black hole (BH) falls below a critical rate, ${\dot M}_{crit}\sim \alpha^2 {\dot M}_{Edd}$, accretion can occur via a hot optically thin flow where most of the dissipated energy is advected inward. We…