相关论文: Retro-MACHOs: Pi in the sky?
Traditional evidence for large amount of dark matter is based on dynamical consideration for systems with $ t_{dyn} \gg t_{obs} $. Recent observational and theoretical developments in gravitational lensing offer a much more robust…
Primordial black holes (PBHs) remain a viable dark matter candidate in the asteroid-mass range. We point out that in this scenario, the PBH abundance would be large enough for at least one object to cross through the inner Solar System per…
How the supermassive black hole SgrA* in the Milky Way Center looks like for a distant observer? It depends on the black hole highlighting by the surrounding hot matter. The black hole shadow (the photon capture cross-section) would be…
We argue that a genuine image of the black hole viewed by a distant observer is not its shadow, but a more compact event horizon image probed by the luminous matter plunging into black hole. The external border of the black hole shadow is…
Black hole-like objects with mass greater than $10 M_{\odot}$, as discovered by gravitational antennas, can produce long time-scale (several years) gravitational microlensing effects. Considered separately, previous microlensing surveys…
The simplest interpretation of the microlensing events observed towards the Large Magellanic Clouds is that approximately half of the mass of the Milky Way halo is in the form of MAssive Compact Halo Objects with $M \sim 0.5 M_{\odot}$. It…
Recently, the image of a Schwarzschild black hole with an accretion disk has been revisited, and it showed that the "photon ring", defined as highly bent light rays that intersect the disk plane more than twice, is extremely narrow and…
Recent developments have ushered in a new era in the field of black hole astrophysics, providing our first direct view of the remarkable environment near black hole event horizons. These observations have enabled astronomers to confirm…
The quantum corrections make the black hole capable of reflection: any particle that approaches the event horizon can bounce back in the outside world. The albedo of the black hole depends on its temperature. The reflection shares physical…
We explore a novel search strategy for dark matter in the form of massive compact halo objects (MACHOs) such as primordial black holes or dense mini-halos in the mass range from $10^{-4}$ to 0.1 solar masses. These objects can…
Black holes in General Relativity are described by space-time metrics that are simpler in comparison to non-vacuum compact objects. However, given the universality of the gravitational pull, it is expected that dark matter accumulates…
Photon spheres play a pivotal role in the imaging of luminous objects near black holes. In this paper, we examine observational appearances of a star freely falling in hairy black holes, which can possess one or two photon spheres outside…
Many present-day galaxies are known to harbor supermassive, >10^6 Mo, black holes. These central black holes must have grown through accretion from less massive seeds in the early universe. The molecules CO and H2 can be used to trace this…
A distinct visual signature occurs in black holes that are surrounded by optically thin and geometrically thick emission regions. This signature is a sharp-edged dip in brightness that is coincident with the black-hole shadow, which is the…
Black holes are thought to describe the geometry of massive, dark compact objects in the universe. To further support and quantify this long-held belief requires knowledge of possible, if exotic alternatives. Here, we wish to understand how…
Since a black hole does not emit light from its interior, nor does it have a surface on which light from nearby sources can be reflected, observational study of black hole physics requires observing the gravitational impact of the black…
Black holes are extremely dense and compact objects from which light cannot escape. There is an overall consensus that black holes exist and many astronomical objects are identified with black holes. White holes were understood as the exact…
At cosmological distances, gravitational lensing can provide a direct measurement of supermassive black hole (SMBH) masses irrespective of their luminosities. Here, we directly estimate the mass of a SMBH in the brightest cluster galaxy…
The mathematical simplicity of black holes, combined with their links to some of the most energetic events in the universe, means that black holes are key objects for fundamental physics and astrophysics. Until recently, it was generally…
MAssive Compact Halo Objects such as brown dwarfs, Jupiters, and black holes are prime candidates to comprise the dark halo of our galaxy. Paczynski noted that objects (dubbed MACHOs) with masses in the range $10^{-6}M_\odot < M \simlt 100…