Related papers: Constraining dark photons and their connection to …
We propose a new method to constrain elastic scattering between dark matter (DM) and standard model particles in the early Universe. Direct or indirect thermal coupling of non-relativistic DM with photons leads to a heat sink for the…
The COBE microwave background temperature fluctuations and the abundance of local rich clusters of galaxies provide the two most powerful constraints on cosmological models. When all variants of the standard cold dark matter (CDM) model are…
Spatially fluctuating primordial magnetic fields (PMFs) inhomogeneously reheat the Universe when they dissipate deep inside the horizon before recombination. Such an energy injection turns into an additional photon temperature perturbation.…
Most inflationary models predict primordial perturbations to be statistically isotropic and homogeneous. Cosmic microwave background (CMB) observations, however, indicate a possible departure from statistical isotropy in the form of a…
We revisit the 21 cm power spectrum from the epoch of cosmic dawn in light of the recent EDGES detection of the 21 cm global signal at frequencies corresponding to $z\sim20$. The shape of the signal suggests that the spin temperature of…
Any particle dark matter (DM) scenario featuring a suppressed power spectrum of astrophysical relevance results in a delay of galaxy formation. As a consequence, such scenarios can be constrained using the global 21-cm absorption signal…
Calculations of the Cosmic Microwave Background lensing power implemented into the standard cosmological codes such as CAMB and CLASS usually treat the surface of last scatter as an infinitely thin screen. However, since the CMB…
The detection of anisotropy in the cosmic microwave background on arcminute scales by the Cosmic Background Imager (CBI) provides us with our first measurement of the damping tail and closes one chapter in the CMB story. We now have…
We explore the fundamental limits to which reionization histories can be constrained using only large-scale cosmic microwave background (CMB) anisotropy measurements. The redshift distribution of the fractional ionization $x_e(z)$ affects…
We study cosmological models involving scalar fields coupled to radiation and discuss their effect on the redshift evolution of the cosmic microwave background temperature, focusing on links with varying fundamental constants and dynamical…
Dark matter and dark energy are usually assumed to couple only gravitationally. An extension to this picture is to model dark energy as a scalar field coupled directly to cold dark matter. This coupling leads to new physical effects, such…
The injection of secondary particles produced by Dark Matter (DM) annihilation around redshift 1000 would inevitably affect the process of recombination, leaving an imprint on Cosmic Microwave Background (CMB) anisotropies and polarization.…
The CMB anisotropy depends sensitively upon the slope and amplitude of primordial density and gravitational wave fluctuations, the baryon density, the Hubble constant, the cosmological constant, the ionization history, {\it etc.} We report…
We calculate the CMB anisotropy in compact hyperbolic universe models using the regularized method of images described in paper-I, including the 'line-of-sight `integrated Sachs-Wolfe' effect, as well as the last-scattering surface terms.…
The Milky Way can act as a large-scale weak gravitational lens of the cosmic microwave background (CMB). We study this effect using a photon ray-tracing code and a Galactic mass distribution with disk, bulge and halo components. For an…
Khatri and Wandelt reported that change in the value of alpha by 1% changes the mean brightness temperature $T_b$ decrement of the CMB due to 21 cm absorption by 5% over the redshift range z $<$ 50. A drawback of their approach is that the…
We examine the cosmic microwave background (CMB) anisotropy for signatures of early quintessence dark energy -- a non-negligible quintessence energy density during the recombination and structure formation eras. In contrast to a…
The injection of secondary particles produced by Dark Matter (DM) annihilation at redshift 100<z<1000 affects the process of recombination, leaving an imprint on Cosmic Microwave Background (CMB) anisotropies. Here we provide a new…
As a local effect of dynamical dark energy, bending of light in the presence of a spherically symmetric and static black hole surrounded by quintessence has been studied. Having in mind recent observational data, we have treated the problem…
We consider the 21\,cm brightness temperature as a probe of the Hubble tension in the framework of an inhomogeneous cosmological model. Employing Buchert's averaging formalism to study the effect of inhomogeneities on the background…