相关论文: Miniclusters in the Axiverse

Axion-like-particles are a well-motivated extension of the Standard Model that can mediate interactions between the dark matter and ordinary matter. Here we consider an axion portal between the two sectors, where the axion couples to dark…

Cosmological evolution of axion field in the early universe might be significantly affected by a thermal friction induced by the axion coupling to thermalized hidden sector. We examine the effects of such a thermal friction on axion dark…

Growing amount of data show evidence for statistical and apparent physical association between low-redshift galaxies and high-redshift quasi-stellar objects, suggesting noncosmological origin of their redshift and failure of classical…

Most matter in the Universe is invisible and unknown, which is called dark matter. A candidate of dark matter is axion, which is an ultra-light particle motivated as a solution for the CP problem. Axions form clouds in a galactic halo,…

The observed values of the cosmological constant {\it and} the abundance of Dark Matter (DM) can be successfully understood, using certain measures, by imposing the anthropic requirement that density perturbations go non-linear and…

Growing amount of observations indicate presence of intrinsically faint quasar subgroup (a few % of known quasars) with noncosmological quantized redshift. Here we find an analytical solution of Einstein equations describing bubbles made…

Rich clusters of galaxies are the most massive virialized systems known. Even though they contain only a small fraction of all galaxies, rich clusters provide a powerful tool for the study of galaxy formation, dark matter, large-scale…

In a recent paper we pointed out that supermassive black holes, with masses ranging from $10^5$ to $10^{10} M_\odot$ form naturally at cosmic dawn if the dark matter is QCD axions or axion-like particles with mass $m > 10^{-16}\,…

The QCD axion is a good dark matter candidate. The observed dark matter abundance can arise from misalignment or defect mechanisms, which generically require an axion decay constant $f_a \sim \mathcal{O}(10^{11})$ GeV (or higher). We…

We present an optical analysis of a sample of 11 clusters built from the EXCPRES sample of X-ray selected clusters at intermediate redshift (z ~ 0.5). With a careful selection of the background galaxies we provide the mass maps…

Dark matter may freeze-out and undergo composite assembly while decoupled from the Standard Model. In this secluded composite scenario, while individual dark matter particles may be too weakly-coupled to detect, the assembled composite can…

The large scale structure of the present Universe is determined by the growth of dark matter density fluctuations and by the dynamical action of dark energy and dark matter. While much progress has been made in recent years in constraining…

Groups and clusters of galaxies occupy a special position in the hierarchy of large-scale cosmic structures because they are the largest and the most massive (from ~10^13 Msun to over 10^15 Msun) objects in the universe that have had time…

If the dark matter sector in the universe is composed by metastable particles, galaxies and galaxy clusters are expected to undergo significant secular evolution from high to low redshift. We show that the decay of dark matter, with a…

We show that dark matter can be accounted for by an axion that solves the strong CP problem, but is much lighter than usual due to a $Z_\mathcal{N}$ symmetry. The whole mass range from the canonical QCD axion down to the ultra-light regime…

About one-fourth of the universe is thought to consist of dark matter. Yet there is no clear understanding about the nature of these particles. Commonly discussed dark matter candidates includes the so called WIMPs or weakly interacting…

We consider a model in which dark matter is stable as it is charged under a Z2 symmetry that is residual after an A4 flavour symmetry is broken. We consider the possibility to generate the quark masses by charging the quarks appropriately…

We propose a scenario in which a strong Peccei-Quinn (PQ) symmetry breaking in the early universe results in large inhomogeneities of the initial QCD axion field value, leading to the formation of very dense axion bubbles. Some of the axion…

The properties of small clusters can differ dramatically from the bulk phases of the same constituents. In equilibrium, cluster assembly has been recently explored, whereas out of equilibrium, the physical principles of clustering remain…

If inflation occurs after the breaking of Peccei-Quinn symmetry then large values of the breaking scale $F$, which are forbidden in conventional axion cosmology, are permitted, provided that we inhabit a region of the Multiverse where the…