Related papers: Constraints on the cosmological coupling of black …
Globular clusters are among the oldest stellar populations in the Milky Way; consequently, they also host some of the oldest known stellar-mass black holes, providing insight into black hole formation and evolution in the early ($z\gtrsim…
Observations of elliptical galaxies suggest that black holes (BHs) might serve as dark energy candidates, coupled to the expansion of the Universe. According to this hypothesis, the mass of a BH could increase as the Universe expands. BH…
We test the possibility that the black holes (BHs) detected by LIGO-Virgo-KAGRA (LVK) may be cosmologically coupled and grow in mass proportionally to the cosmological scale factor to some power $k$, which may also act as the dark energy…
Gravitational waves from black-hole merging events have revealed a population of extra-galactic BHs residing in short-period binaries with masses that are higher than expected based on most stellar evolution models - and also higher than…
It has recently been suggested that black holes (BHs) may grow with time, so that their mass is proportional to the cosmological scale factor to the power $n$, with suggested values $n \approx 3$ for supermassive BHs in elliptical galaxies.…
Coupling of black hole mass to the cosmic expansion has been suggested as a possible path to understanding the dark energy content of the Universe. We test this hypothesis by comparing the supermassive black hole (SMBH) mass density at…
It was recently suggested that "cosmologically coupled" black holes with masses that increase in proportion to the volume of the Universe might constitute the physical basis of dark energy. We take this claim at face value and discuss its…
Soon after the Gaia data release (DR) 3 in June 2022, some candidates (and one confirmed) of detached black hole (BH) - luminous companion (LC) binaries have been reported. Existing and future detections of astrometric BH-LC binaries will…
Detection of black holes (BHs) with detached luminous companions (LCs) can be instrumental in connecting the BH properties with their progenitors' since the latter can be inferred from the observable properties of the LC. Past studies…
Nearly a hundred of binary black holes (BBHs) have been discovered with gravitational-wave signals emitted at their merging events. Thus, it is quite natural to expect that significantly more abundant BBHs with wider separations remain…
The Gaia mission and its follow-up observations have discovered a few candidates of non-interacting single black holes (BHs) and visible stars, Gaia BH1, BH2, and BH3, collectively called ``astrometric BH binaries''. This paper investigates…
Three black holes (BHs) in wide binaries - Gaia BH1, BH2 and BH3 - were recently discovered. The likely progenitors of the BHs were massive stars that experienced a supergiant phase, reaching radii of ~1000 Rsun, before collapsing to form…
We show that -- in the framework of general relativity (GR) -- if black holes (BHs) are singularity-free objects, they couple to the large-scale cosmological dynamics. We find that the leading contribution to the resulting growth of the BH…
Stellar-mass black holes (BHs) above $30 M_\odot$ are predicted to form from low-metallicity progenitors, but direct detections of such systems in the Milky Way remain scarce. Motivated by the recent discovery of Gaia BH3, a $33 M_\odot$ BH…
Context. The black holes discovered using Gaia, especially Gaia BH1 and BH2, have low mass companions of solar-like metallicity in wide orbits. For standard isolated binary evolution formation channels including interactions such an extreme…
Recently, several non-interacting black hole-stellar binaries have been identified in Gaia data. For example, Gaia BH1, where a Sun-like star is in a moderate eccentricity (e=0.44), 185-day orbit around a black hole. This orbit is difficult…
Theory and observations suggest that single-star evolution is not able to produce black holes (BHs) with masses in the range $3-5M_{\odot}$ and above $\sim 45M_{\odot}$, referred to as the lower mass gap (LMG) and the upper mas gap (UMG),…
Astrometry from the Gaia mission was recently used to discover the two nearest known stellar-mass black holes (BHs), Gaia BH1 and Gaia BH2. Both systems contain $\sim 1\,M_{\odot}$ stars in wide orbits ($a\approx$1.4 AU, 4.96 AU) around…
A $33\,M_\odot$ black hole (BH) was recently discovered in an 11.6-year binary only 590 pc from the Sun. The system, Gaia BH3, contains a $0.8\,M_\odot$ low-metallicity giant ($\rm [M/H]=-2.2$) that is a member of the ED-2 stellar stream.…
Current theoretical models predict a mass gap with a dearth of stellar black holes (BHs) between roughly $50\,M_\odot$ and $100\,M_\odot$, while, above the range accessible through massive star evolution, intermediate-mass BHs (IMBHs) still…