Related papers: 21-cm observations and warm dark matter models
We study the absorption along lines of sight toward high-z radio sources caused by the 21 cm transition of neutral hydrogen in the intergalactic medium (IGM) before reionization. Using semi-analytic methods, we compute the number density of…
We present and compare several cosmological constraints on the cross section for elastic scattering between dark matter (DM) and baryons, for cross sections with a range of power-law dependences on the DM-baryon relative velocity $v$,…
While the $\mathbb{Z}_3$ symmetric dark matter models have shown tremendous prospects in addressing a number of (astro-)particle physics problems, they can leave interesting imprints on cosmological observations as well. We consider two…
Warm dark matter (WDM) means DM particles with mass m in the keV scale. For large scales, (structures beyond ~ 100 kpc) WDM and CDM yield identical results which agree with observations. For intermediate scales, WDM gives the correct…
The stronger than expected 21-cm absorption was observed by EDGES recently, and another anomaly of $^8$Be transitions would be signatures of new interactions. These two issues may be related to each other, e.g., pseudoscalar $A$ mediated…
Beyond reionization epoch cosmic hydrogen is neutral and can be directly observed through its 21 cm line signal. If dark matter (DM) decays or annihilates the corresponding energy input affects the hydrogen kinetic temperature and ionized…
The 21cm forest, narrow absorption features in the spectra of high redshift radio sources caused by intervening neutral hydrogen, offers a unique probe of the intergalactic medium and small-scale structures during reionization. While…
This study introduces novel constraints on the free-streaming of thermal relic warm dark matter (WDM) from Lyman-$\alpha$ forest flux power spectra. Our analysis utilises a high-resolution, high-redshift sample of quasar spectra observed…
We explore the complete history of the 21-cm signal in the redshift range z = 7-40. This redshift range includes various epochs of cosmic evolution related to primordial star formation, and should be accessible to existing or planned…
The H atoms inside minihalos (i.e. halos with virial temperatures T_vir < 10^4 K, in the mass range roughly from 10^4 M_sun to 10^8 M_sun) during the cosmic dark ages in a LambdaCDM universe produce a redshifted background of…
Structure formation at small cosmological scales provides an important frontier for dark matter (DM) research. Scenarios with small DM particle masses, large momenta or hidden interactions tend to suppress the gravitational clustering at…
The unexpectedly strong 21cm absorption signal detected by the EDGES experiment suggests that the baryonic gas was colder at redshift $z\sim 17$ than predicted in the standard scenario. We discuss a mechanism to lower the baryon temperature…
We calculate the redshift evolution of the global 21cm signal in the first billion years using a semi-analytic galaxy formation model, DELPHI, that jointly tracks the assembly of dark matter halos and their constituent baryons including the…
Warm dark matter (WDM) is an intriguing model of structure formation from the point of view of both cosmology and particle physics. We consider a one-parameter family of WDM models. The linear power spectra for these models is calculated…
We study the constraints that high-redshift structure formation in the universe places on warm dark matter (WDM) dominated cosmological models. We modify the extended Press-Schechter formalism to derive the halo mass function in WDM models.…
Measurements of 21cm intensity mapping (IM) during the dark ages can potentially provide us with an unprecedented window on high redshifts and small scales. One of the main advantages this can bring involves the possibility to probe the…
It is thought that the Universe went through an early period known as the Dark Ages, during which primeval density fluctuations grew to form the first luminous objects, marking the beginning of Cosmic Dawn around 100 million years after the…
The post-recombination streaming of baryons through dark matter keeps baryons out of low mass (<10^6 solar masses) halos coherently on scales of a few comoving Mpc. It has been argued that this will have a large impact on the 21-cm signal…
The 21-cm forest is a promising probe of the Epoch of Reionization. The local state of the intergalactic medium (IGM) is encoded in the spectrum of a background source (radio-loud quasars or gamma ray burst afterglow) by absorption at the…
Using the latest upper limits on the 21-cm power spectrum at $z\approx9.1$ from the Low Frequency Array (LOFAR), we explore regions of parameter space which are inconsistent with the data. We use 21CMMC, a Monte Carlo Markov Chain sampler…