Related papers: Constraints on cosmic strings from ultracompact mi…
Ultracompact Minihalos (UCMHs) have been proposed as a type of dark matter sub-structure seeded by large-amplitude primordial perturbations and topological defects. UCMHs are expected to survive to the present era, allowing constraints to…
For a Gaussian spectrum of primordial density fluctuations, ultracompact minihalos (UCMHs) of dark matter are expected to be produced in much greater abundance than, e.g., primordial black holes. Forming shortly after matter-radiation…
The fraction of cosmic string loops which collapse to form black holes is estimated using a set of realistic loops generated by loop fragmentation. The smallest radius sphere into which each cosmic string loop may fit is obtained by…
The cosmological features of primordial black holes formed from collapsed cosmic string loops are studied. Observational restrictions on a population of primordial black holes are used to restrict $f$, the fraction of cosmic string loops…
A small fraction, $f$, of cosmic string loops can collapse to form Primordial Black Holes (PBHs). Constraints on the abundance of PBHs can therefore be used to constrain $f$. We update these calculations, taking into account the PBH…
Ultracompact minihalo (UCMH) is a special type of dark matter halo with a very steep density profile which may form in the early universe seeded by an overdense region or a primordial black hole. Constraints on its abundance give valuable…
A new kind of dark matter structures, ultracompact minihalos (UCMHs) was proposed recently. They would be formed during the radiation dominated epoch if the large density perturbations are existent. Moreover, if the dark matter is made up…
Cosmic strings can be created in the early universe during symmetry-breaking phase transitions, such as might arise if the gauge structure of the standard model is extended by additional U(1) factors at high energies. Cosmic strings present…
Cosmic strings are topological defects which can be formed in GUT-scale phase transitions in the early universe. They are also predicted to form in the context of string theory. The main mechanism for a network of Nambu-Goto cosmic strings…
Ultracompact dark matter minihalos (UCMHs) would be formed during the earlier universe if there were large density perturbations. If the dark matter can decay into the standard model particles, such as neutrinos, these objects would become…
The fragmentation of horizon crossing superstrings creates loops that accrete and bind to collapsing matter perturbations if the string tension is less than a critical value and if the loops are large-scale. For typical model parameters…
In theories with cosmic strings, a small fraction of string loops may collapse to form black holes. In this Letter, various constraints on such models involving black holes are considered. Hawking radiation from black holes, gamma and…
Ultracompact minihalos (UCMHs) are dense dark matter structures which can form from large density perturbations shortly after matter-radiation equality. If dark matter is in the form of Weakly Interacting Massive Particles (WIMPs), then…
It has been proposed that ultracompact minihalos (UCMHs) might be formed in earlier epoch. If dark matter consists of Weakly Interacting Massive Particles (WIMPs), UCMHs can be treated as the {\gamma}-ray sources due to dark matter…
We describe the detailed study and results of high-resolution numerical simulations of string-induced structure formation in open universes and those with a non-zero cosmological constant. The effect from small loops generated from the…
Compared with that of standard dark matter halos, the density profile of the recently proposed new kind of dark matter structure named ultracompact minihalos (UCMHs) is steeper and its formation time is earlier. If the dark matter is…
Cosmic strings with small-scale structure have a coarse-grained mass per unit length $\mu$ which is larger than the string tension. This leads to an effective Newtonian gravitational line source and to a characteristic translational…
Cosmic strings appear in many well-motivated extensions to the standard model of particle physics. If they exist, an abundant population of compact objects known as cosmic string loops permeate the Universe at all times, providing a…
Cosmic superstrings are produced towards the end of the brane inflation. If the string tension is low enough, loops tend to be relatively long-lived. The resultant string network is expected to contain many loops which are smaller than…
Using recent simulation results, we provide the mass and speed spectrum of cosmic string loops. This is the quantity of primary interest for many phenomenological signatures of cosmic strings, and it can be accurately predicted using…