Related papers: Black holes shielded by magnetic fields
We show that the near horizon of a generic non-extremal black hole (BH) can be understood in terms of a Carrollian geometry with two null directions, also called a String-Carroll (SC) geometry. The base space of this fibre-bundle structure…
It has been proposed that some black holes (BHs) in binary black hole (BBH) systems are born from "hierarchical mergers" (HM); i.e. earlier mergers of smaller BHs. These HM products have spin magnitudes $\chi \sim 0.7$, and, if they are…
The very latest observation of $M87$ supermassive black hole (BH) by the Event Horizon Telescope (EHT) provides the accretion onto BHs is an interesting study in the theory of gravity. We study the geodesics structure and accretion near a…
Black holes play a crucial role in the understanding of the gravitational interaction. Through the direct observation of the shadow of a black hole by the event horizon telescope and the detection of gravitational waves of merging black…
Recent work has linked the quiescent luminosities and hard/soft spectral state switches of neutron stars (NSs) to their spinning magnetic fields. It is shown here that the quiescent luminosities and spectral switches of galactic black hole…
A 70Msun BH was discovered in Milky Way disk in a long period and almost circular detached binary system (LB-1) with a high metallicity 8Msun B star companion. Current consensus on the formation of BHs from high metallicity stars limits the…
Supermassive black holes (SMBHs) are common in local galactic nuclei, and SMBHs as massive as several billion solar masses already exist at redshift z=6. These earliest SMBHs may grow by the combination of radiation-pressure-limited…
We envisage a black hole perturbed by a force-free magnetic field (FFMF) outside and attempt to determine its structure. We suppose the metric that describes this black hole is of the static spherical type, that is Schwarzschild, and the…
The Hawking-Perry-Strominger (HPS) work [1] states a new controversial idea about the black hole (BH) information paradox [2-5] where BHs maximally entropize and encode information in their event horizon area [6,7], with no "hair" were…
Merging compact black-hole (BH) binaries are likely to exist in the nuclear star clusters around supermassive BHs (SMBHs), such as Sgr A$^\ast$. They may also form in the accretion disks of active galactic nuclei. Such compact binaries can…
Primordial Black Holes (PBHs) in the mass range $\sim 10^{17}- 10^{22}$g are currently unconstrained, and can constitute the full Dark Matter (DM) density of the universe. Motivated by this, in the current work, we aim to relate the…
Primordial black holes (PBHs) can answer a plethora of cosmic conundra, among which the origin of the cosmic magnetic fields. In particular, supermassive PBHs with masses $M_\mathrm{PBH}>10^{10} M_\odot$ and furnished with a plasma-disk…
We address the astrophysical imaging of a family of deformed Kerr black holes (BHs). These are stationary, asymptotically flat black hole (BH) spacetimes, that are solutions of General Relativity minimally coupled to a massive, complex…
The theoretical properties of the black holes (BHs) and of the universe were derived from a unified relativistic theory based on a generalization of local relativity for nonlocal cases in gravitational fields and a quantized standing wave…
To what extent are all astrophysical, dark, compact objects both black holes (BHs) and described by the Kerr geometry? We embark on the exercise of defying the universality of this remarkable idea, often called the "Kerr hypothesis". After…
The accretion of dark matter around the primordial black holes (PBHs) could lead to the formation of surrounding minihalos, whose mass can be several orders of magnitude higher than the central PBH mass. The gravitational microlensing…
We give a full metric describing the gravitational field of a static and axisymmetric thin disk without radial pressure encircling a Schwarzschild black hole. The disk density profiles are astrophysically realistic, stretching from the…
We investigate a recently derived Schwarzschild-like black hole immersed in a Dehnen-type $(\alpha,\beta,\gamma)=(1,4,5/2)$ dark matter (DM) halo. We obtain constraints on the two model parameters, i.e., the halo core radius $r_s$ and the…
Using the concept of apparent horizon for dynamical black holes, we revisit the formation of primordial black holes (PBH) in the early universe for both linear and non-linear regimes. First, we develop the perturbation theory for…
The frequent detection of binary mergers of $\sim 30 M_{\odot}$ black holes (BHs) by the Laser Interferometer Gravitational-Wave Observatory (LIGO) rekindled researchers' interest in primordial BHs (PBHs) being dark matter (DM). In this…