Related papers: Oort Cloud Bombardment by Dark Matter
A primordial black hole (PBH) is thought to be made of the regular matter or ordinary mass ($M$) only, and hence could have already been decayed due to the Hawking radiation if its initial ordinary mass were $\lesssim 5 \times 10^{11}$ kg.…
Although dark matter in galaxies may consist of elementary particles different from those that make up ordinary matter and that would be smoothly distributed (still undetected), the so-called primordial black holes (PBHs) formed soon after…
We study the matter power spectrum constraint on primordial black holes (PBH) by the dark matter (DM) emitted through Hawking radiation. We particularly focus on the scenario where PBH, with mass ranges between 1g and $10^9$g, evaporates…
It has long been assumed that the planet Jupiter acts as a giant shield, significantly lowering the impact rate of small bodies on the Earth. However, until recently, very little work had been carried out examining the role played by…
Primordial Black Holes (PBHs) are of interest in many cosmological contexts. PBHs lighter than about 1012 kg are predicted to be directly detectable by their Hawking radiation. This radiation should produce both a diffuse extragalactic…
The QCD axion can solve the Strong CP Problem and be the dark matter of our universe. If the PQ symmetry breaking scale associated with the axion is below the inflationary reheating temperature, axion strings and domain walls populate the…
Primordial black holes (PBHs) from the early Universe have been connected with the nature of dark matter and can significantly affect cosmological history. We show that coincidence dark radiation and density fluctuation gravitational wave…
Using the BATSE survey data I find that quite small fraction of GRBs numbering 37 sources seems to emit the radiation similar to thermal bremsstrahlung in the range 20 to 300 keV. I suggest that these bursts may perhaps occur from collision…
The Oort cloud (OC) probably formed more than 4$\,$Gyr ago and has been moving with the Sun in the Galaxy since, exposed to external influences, most prominently to the Galactic tide and passing field stars. Theories suggest that other…
Quantum evaporation of a black hole is conventionally studied semiclassically by assuming self-similarity of the black hole throughout the evaporation process. However, its validity was recently questioned, and the lifetime of a black hole…
The computation of PBH (primordial black hole) production from primordial perturbations has recently been improved by considering a more accurate relation between the primordial power spectrum and the PBH mass variance. We present here…
The high sensitivity of upcoming space-based gravitational wave detectors suggests the possibility that if halo dark matter were composed of primordial black holes (PBHs) with mass between $10^{16}$ g and 10$^{20}$ g, the gravitational…
If 0.1% of the dark matter in the Coma cluster is constituted by primordial black holes (PBHs) with masses ranging from 10^-19 to 10^-17 solar masses, then the observed GeV {\gamma}-ray emission from the cluster could potentially be…
Numerous microlensing survey programs have constrained the possibility of dark matter existing in the form of compact objects within the Galactic halo. These constraints on the dark matter fraction were derived under the assumption of…
Primordial black holes (PBHs) are the plausible candidates for the cosmological dark matter. Theoretically, PBHs with masses $M_{\rm PBH}$ in the range of $4\times10^{14}\sim 10^{17}\,{\rm g}$ can emit sub-GeV electrons and positrons…
We propose a novel mechanism where Primordial Black Hole (PBH) dark matter is formed much later in the history of the universe between the epoch of Big Bang Nucleosynthesis (BBN) and Cosmic Microwave Background (CMB) photon decoupling. In…
The complete sample of large-perihelion nearly-parabolic comets discovered during the period 1901-2010 is studied starting from their orbit determination. Next, an orbital evolution that includes three perihelion passages…
Long-period radio transients have unusual properties that challenge their interpretation as pulsars or magnetars. We examine whether they might instead be powered by primordial black holes (PBHs) making repeated passages through a host…
Primordial black holes (PBHs) remain one of the most intriguing candidates for dark matter and a unique probe of physics at extreme curvatures. Here, we examine their formation in a bounce cosmology when the post-crunch universe inherits a…
Since 1950 when Oort published his paper on the structure of the cloud of comets it is believed that stars passing near this hypothetical cometary reservoir play an important role in the dynamical evolution of long period comets and…