相关论文: Possible interaction between baryons and dark-matt…
The epoch of the formation of the first stars, known as the cosmic dawn, has emerged as a new arena in the search for dark matter. In particular, the first claimed 21-cm detection exhibits a deeper global absorption feature than expected,…
In the standard cosmology, it is believed that there are two relatively weak and distinct band-limited absorption features, with the first absorption minima near 20 MHz ($z\sim70$) and the other minima at higher frequencies between 50-110…
Recently the EDGES collaboration reported an anomalous absorption signal in the sky-averaged 21-cm spectrum around $z=17$. Such a signal may be understood as an indication for an unexpected cooling of the hydrogen gas during or prior to the…
Observations of the redshifted 21-cm signal (in absorption or emission) allow us to peek into the epoch of "dark ages" and the onset of reionization. These data can provide a novel way to learn about the nature of dark matter, in particular…
Understanding the formation and evolution of the first stars and galaxies represents one of the most exciting frontiers in astronomy. Since the universe was filled with hydrogen atoms at early times, the most promising probe of the epoch of…
The astrophysics of cosmic dawn, when star formation commenced in the first collapsed objects, is predicted to be revealed as spectral and spatial signatures in the cosmic radio background at long wavelengths. The sky-averaged redshifted…
The recent detection of an anomalously strong 21-cm signal of neutral hydrogen from Cosmic Dawn by the EDGES Low-Band radio experiment can be explained if cold dark matter particles scattered off the baryons draining excess energy from the…
The Dark Ages, probed by the redshifted 21-cm signal, is the ideal epoch for a new rigorous test of the standard LCDM cosmological model. Divergences from that model would indicate new physics, such as dark matter decay (heating) or…
Dark matter-baryon interactions can cool the baryonic fluid, which has been shown to modify the cosmological 21-cm global signal. We show that in a two-component dark sector with an interacting millicharged component, dark matter-baryon…
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 formation of the first stars is an exciting frontier area in astronomy. Early redshifts z ~ 20 have become observationally promising as a result of a recently recognized effect of a supersonic relative velocity between the dark matter…
The redshifted 21-cm line of hydrogen holds great potential for the study of cosmology, as it can probe otherwise unobservable cosmic epochs. In particular, measurements of the 21-cm power spectrum during cosmic dawn---the era when the…
At cosmic dawn, the 21-centimeter signal from intergalactic hydrogen was driven by Lyman-$\alpha$ photons from some of the earliest stars, producing a spatial pattern that reflected the distribution of galaxies at that time. Due to the…
A recent observation by the EDGES collaboration shows a strong absorption signal in the global 21-cm spectrum from around a redshift of $z = 17$. This absorption is stronger than the maximum prediction by existing models and indicates that…
A hypothetical particle known as the axion holds the potential to resolve both the cosmic dark matter riddle and particle physics' long-standing, strong CP dilemma. An unusually strong 21-cm absorption feature associated with the initial…
The hydrogen 21-cm signal is predicted to be the richest probe of the young Universe including eras known as the cosmic Dark Ages, the Cosmic Dawn when the first star and black hole formed, and the Epoch of Reionization. This signal holds…
The sky-averaged (global) 21-cm signal is a powerful probe of the intergalactic medium (IGM) prior to the completion of reionization. However, it has so far been unclear that even in the best case scenario, in which the signal is accurately…
The origin and composition of the cosmological dark matter remain a mystery. However, upcoming 21-cm measurements during cosmic dawn, the period of the first stellar formation, can provide new clues on the nature of dark matter. During this…
The EDGES experiment recently announced evidence for a broad absorption feature in the sky-averaged radio spectrum around 78 MHz, as may result from absorption in the 21 cm line by neutral hydrogen at z~15-20. If confirmed, one implication…
We describe how the high-redshift 21-cm background can be used to improve both our understanding of the fundamental cosmological parameters of our Universe and exotic processes originating in the dark sector. The 21-cm background emerging…