Related papers: Reionization from cosmic string loops
Measurements of the CMB temperature anisotropy and the temperature-polarization cross correlation by WMAP suggest a reionization redshift of $z \sim 17 \pm 5$. On the other hand, observations of high redshift galaxies indicate a presence of…
We investigate the dependence of the epoch of reionization on the properties of cosmological perturbations, in the context of cosmologies permitted by WMAP. We compute the redshift of reionization using a simple model based on the…
We examine the effects of cosmic strings on structure formation and on the ionization history of the universe. While Gaussian perturbations from inflation are known to provide the dominant contribution to the large scale structure of the…
Electromagnetic radiation from superconducting cosmic string loops can reionize neutral hydrogen in the universe at very early epochs, and affect the cosmic microwave background (CMB) temperature and polarization correlation functions at…
Cosmic strings, if they exist, source nonlinear and non-Gaussian perturbations all the way back to the time of equal matter and radiation (and earlier). Here, we compute the mass function of halos seeded by a scaling distribution of cosmic…
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 produce charged particles which, by emitting electromagnetic radiation, partially ionize neutral hydrogen during the dark ages. Corrections to the ionization fraction of neutral hydrogen induced by cosmic strings could lead…
We describe a new mechanism, whose ingredients are realised in string compactifications, for the formation of cosmic (super)string networks. Oscillating string loops grow when their tension $\mu$ decreases with time. If $2H + \dot{\mu}/\mu…
Recent discoveries of super-massive black holes at high redshifts indicate a possible tension with the standard Lambda CDM paradigm of early universe cosmology which has difficulties in explaining the origin of the required nonlinear…
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…
Cosmic strings are expected to form loops. These can act as seeds for accretion of dark matter, leading to the formation of ultracompact minihalos (UCMHs). We perform a detailed study of the accretion of dark matter onto cosmic string loops…
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…
Star-forming galaxies in the early universe provide us with perhaps the most natural way of explaining the reionization of the universe. Current observational results are sufficiently comprehensive, as to allow us to approximately calculate…
A remarkable result of the Wilkinson Microwave Anisotropy Probe (WMAP) observations is that the universe was significantly reionized at large redshifts. The standard explanation is that massive stars formed early and reionized the universe…
Cosmic string loops lead to nonlinear baryon overdensities at early times, even before the time which in the standard LCDM model corresponds to the time of reionization. These overdense structures lead to signals in 21cm redshift surveys at…
Large-scale coherent magnetic fields are observed in galaxies and clusters, but their ultimate origin remains a mystery. We reconsider the prospects for primordial magnetogenesis by a cosmic string network. We show that the magnetic flux…
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…
We investigate the contribution made by small loops from a cosmic string network as seeds for large-scale structure formation. We show that cosmic string loops are highly correlated with the long-string network on large scales and therefore…
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…
Gravitational wave signatures from cosmic strings are analyzed numerically. Cosmic string networks form during phase transistions in the early universe and these networks of long cosmic strings break into loops that radiate energy in the…