Related papers: Upcoming SKA precursor surveys and sensitivity to …
As a first step toward constraining the efficiency of the star formation episodes that lead to elliptical (E) and lenticular (S0) K+A galaxies, a survey for HI within a sample of E and S0 K+A galaxies and their likely progenitors (i.e.,…
We analyze the distribution of galaxy HI masses detected in a large, deep HI survey conducted at the Arecibo observatory, and we find possible evidence of a faint-end steepening of the mass function similar to what has been found optically.…
Accurately predicting the shape of the HI velocity function of galaxies is regarded widely as a fundamental test of any viable dark matter model. Straightforward analyses of cosmological $N$-body simulations imply that the $\Lambda$CDM…
In a 21 cm neutral hydrogen survey of approximately 55 sq deg out to a redshift of cz=8340 km/s, we have identified 75 extragalactic HI sources. These objects comprise a well-defined sample of extragalactic sources chosen by means that are…
Using a spectral stacking technique, we measure the neutral hydrogen (HI) properties of a sample of galaxies at $z < 0.11$ across 35 pointings of the Westerbork Synthesis Radio Telescope (WSRT). The radio data contains 1,895 galaxies with…
Results from the Arecibo HI Strip Survey, an unbiased extragalactic HI survey, combined with optical and 21cm follow-up observations, determine the HI Mass Function and the cosmological mass density of HI at the present epoch. Both are…
Upcoming experiments such as Hydrogen Epoch of Reionization Array (HERA) and Square Kilometre Array (SKA) are intended to measure the 21cm signal over a wide range of redshifts, representing an incredible opportunity in advancing our…
The empirical studies of cold gas content serve as an essential aspect in comprehending the star formation activities and evolution in galaxies. However, it is not straightforward to understand these processes because they depend on various…
We investigate the feasibility of measuring weak gravitational lensing using 21cm intensity mapping with special emphasis on the performance of the planned Square Kilometre Array (SKA). We find that the current design for SKA-Mid should be…
We discuss the detection of redshifted line and continuum emission at radio wavelengths using a Square Kilometer Array (SKA), specifically from low-excitation rotational molecular line transitions of CO and HCN (molecular lines), the…
Observations of the neutral Hydrogen (\HI ) 21-cm signal hold the potential of allowing us to map out the cosmological large scale structures (LSS) across the entire post-reionization era ($z \leq 6$). Several experiments are planned to map…
We present a comprehensive model to predict the rate of spectroscopic confusion in HI surveys, and demonstrate good agreement with the observable confusion in existing surveys. Generically the action of confusion on the HI mass function was…
To establish the connection between galaxies and UV-detected absorption systems in the local universe, a deep ($g\leq20$) and wide ($\sim20^{\prime}$ radius) galaxy redshift survey is presented around 47 sight lines to UV-bright AGN…
We show how precision lensing measurements can be obtained through the lensing magnification effect in high redshift 21cm emission from galaxies. Normally, cosmic magnification measurements have been seriously complicated by galaxy…
We model the distribution of neutral Hydrogen (HI hereafter) in the post-reionization universe. This model uses gravity only N-Body simulations and an ansatz to assign HI to dark matter haloes that is consistent with observational…
We present HI 21 cm spectroscopy from the GBT for the host galaxies of 31 nearby AGNs with direct M$_{\textrm{BH}}$ measurements from reverberation mapping. These are the first published HI detections for 12 galaxies, and the spectral…
Very sensitive HI 21cm observations have been made in 860 directions at dec >= -43deg in search of weak, Galactic, high-velocity HI emission lines at moderate and high Galactic latitudes. One-third of the observations were made toward…
We present an overview of the theory of high-redshift star and X-ray source formation, and how they affect the 21-cm background. Primary focus is given to Lyman alpha pumping and X-ray heating mechanisms at cosmic dawn, opening a new…
Detecting HI using redshifted Ly-alpha absorption lines is 1e6 times more sensitive than using the 21cm emission line. We review recent discoveries of HI Ly-alpha absorbers made with the Hubble Space Telescope (HST) which have allowed us a…
The survey speed of ASKAP makes it a prime instrument with which to survey the HI universe, enabling it to carry out both wide surveys of the entire sky, as well as deep surveys covering cosmologically representative volumes. Here, the use…