Related papers: An evolutionary model for V404 Cyg system
All stellar mass black holes have hitherto been identified by X-rays emitted by gas that is accreting onto the black hole from a companion star. These systems are all binaries with black holes below 30 M$_{\odot}$$^{1-4}$. Theory predicts,…
Hierarchical massive quadruple systems are ideal laboratories for examining the theories of star formation, dynamical evolution, and stellar evolution. The successive mergers of hierarchical quadruple systems might explain the mass gap…
The X-ray binary 4U 1954+31 has been classified as a Low Mass X-ray Binary (LMXB) containing a M giant and a neutron star (NS). It has also been included in the rare class of X-ray symbiotic binaries (SyXB). The Gaia parallax, infrared…
Both the anomalous magnetic braking of Ap/Bp stars and the surrounding circumbinary disk models can account for the formation of black hole (BH) low-mass X-ray binaries (LMXBs), while the simulated effective temperatures of the donor stars…
Recent studies of massive binaries with putative black hole companions have uncovered a phase of binary evolution that has not been observed before, featuring a bloated stripped star that very recently ceased transferring mass to a…
It has been suggested that black-hole low-mass X-ray binaries (BHLMXBs) with short orbital periods may have evolved from BH binaries with an intermediate-mass secondary, but the donor star seems to always have higher effective temperatures…
The recent discovery of the binary black hole (BBH) merger event GW190521, between two black holes (BHs) of $\approx100M_\odot$, and as well as other massive BBH merger events involving BHs within the pair-instability supernova (PSN) mass…
We study the optical evolution of the 2015 outburst in V404 Cyg, with emphasis on the peculiar nebular phase and subsequent decay to quiescence. From the decay timescale of the Balmer emission associated with the nebula we measure an…
Upsilon Sagittarii is a hydrogen-deficient binary that has been suggested to be in its second stage of mass transfer, after the primary has expanded to become a helium supergiant following core helium exhaustion. A tentative identification…
Most massive stars are believed to be born in close binary systems where they can exchange mass, which impacts the evolution of both binary components. Their evolution is of great interest in the search for the progenitors of gravitational…
We conducted the first long-term (75 days) X-ray monitoring of the black hole low mass X-ray binary V404 Cyg, with the goal of understanding and characterizing its variability during quiescence. The X-ray light curve of V404 shows several…
The relation between the mass and spin of stellar-mass binary black holes (BBHs) has been proposed to be a smoking gun for the presence of multiple formation channels for compact objects. First-generation black holes (BHs) formed by…
X-ray binaries with black hole (BH) accretors and massive star donors at short orbital periods of a few days can evolve into close binary BH systems (BBH) that merge within the Hubble time through stable mass transfer evolution. From…
The evolutionary status of the low mass X-ray binary SAX J1808.4-3658 is simulated by following the binary evolution of its possible progenitor system through mass transfer, starting at a period of $\sim$6.6 hr. The evolution includes…
We show that a common evolutionary history can produce the black hole binaries in the Galaxy in which the black holes have masses of ~ 5-10 M_sun. In with low-mass, <~ 2.5 M_sun, ZAMS (zero age main sequence) companions, the latter remain…
The growing database of gravitational-wave (GW) detections with the binary black holes (BHs) merging in the distant Universe contains subtle insights into their formation scenarios. One of the puzzling properties of detected GW sources is…
The recently claimed discovery of a massive ($M_\mathrm{BH}=68^{+11}_{-13}\,M_\odot$) black hole in the Galactic solar neighborhood has led to controversial discussions because it severely challenges our current view of stellar evolution. A…
Spin and mass properties provide essential clues in distinguishing the origins of coalescing black holes (BHs). With a dedicated semiparametric population model for the coalescing binary black holes (BBHs), we identify two distinct…
We explore the implications of the observed low spins aligned with the orbital axis in Advanced~LIGO~O1 run on binary black hole (BBH)~merger scenarios in which the merging BBHs have evolved from field binaries. The coalescence time…
We report the results of WBVR photometry of the massive close x-ray binary V1341 Cyg=Cyg X-2 in 1986-1992. In the "off" state the amplitudes of the periodic component of light variations lie in the $0^{m}.265 - 0^{m}.278$ and $0^{m}.290 -…