Related papers: Extragalactic HI Surveys
We present an analytic model to predict the HI mass contributed by confused sources to a stacked spectrum in a generic HI survey. Based on the ALFALFA correlation function, this model is in agreement with the estimates of confusion present…
The conformity effect, indicating the evolution of a galaxy is related to its surrounding neighbour galaxies as far as a few Mpc, is an interesting phenomenon in the modeling of galaxy and evolution. Here we study the conformity effect of…
We present the results of the HIGHz Arecibo survey, which measured the HI content of 39 galaxies at redshift $z>0.16$ selected from the Sloan Digital Sky Survey. These are all actively star-forming, disk-dominated systems in relatively…
We investigate the properties of HI-rich galaxies detected in blind radio surveys within the hierarchical structure formation scenario using a semi-analytic model of galaxy formation. By drawing a detailed comparison between the properties…
We have carried out an HI stacking analysis of a volume-limited sample of ~5000 galaxies with imaging and spectroscopic data from GALEX and the Sloan Digital Sky Survey, which lie within the current footprint of the Arecibo Legacy Fast ALFA…
We measure the HI mass function (HIMF) and velocity width function (WF) across environments over a range of masses $7.2<\log(M_{HI}/M_{\odot})<10.8$, and profile widths $1.3\log(km/s)<\log(W)<2.9\log(km/s)$, using a catalog of ~7,300…
We use a stacking technique to measure the average HI content of a volume-limited sample of 1871 AGN host galaxies from a parent sample of galaxies selected from the SDSS and GALEX imaging surveys with stellar masses greater than 10^10…
The Arecibo Galaxy Environment Survey (AGES) is one of several HI surveys utilising the new Arecibo L-band Feed Array (ALFA) fitted to the 305m radio telescope at Arecibo. The survey is specifically designed to investigate various galactic…
We discuss the selection and observations of a large sample of nearby galaxies, which we are using to quantify the star formation activity in the local Universe. The sample consists of 334 galaxies across all Hubble types from S0/a to Im…
Future galaxy surveys will map the galaxy distribution in the redshift interval $0.5<z<2$ using near-infrared cameras and spectrographs. The primary science goal of such surveys is to constrain the nature of the dark energy by measuring the…
Observations show that galaxies in galaxy clusters are strongly influenced by their environment. There is growing evidence that some galaxies in groups show similar properties to galaxies in clusters, such as redder colours and gas…
The HI content of Hickson Compact Groups in the southern hemisphere is measured using data from the HI Parkes All Sky Survey (HIPASS), and dedicated observations using the narrowband filter on the Multibeam instrument on the Parkes…
The application of artificial neural networks (ANNs) for the estimation of HI gas mass fraction (\fgas) is investigated, based on a sample of 13,674 galaxies in the Sloan Digital Sky Survey (SDSS) with HI detections or upper limits from the…
Using a semi-analytic approach, we estimate halo spins for a large sample of HI-rich galaxies from the Arecibo Legacy Fast Alfa Survey and examine the correlation between HI mass fractions and halo spins. Our analysis reveals a strong…
Here we present Australia Telescope Compact Array HI maps of 16 HI sources in six Group Evolution Multiwavelength Study (GEMS) groups that were previously observed with the Parkes telescope. The higher spatial resolution of the ATCA allows…
The number density of extragalactic 21-cm radio sources as a function of their spectral line-widths -- the HI width function (HIWF) -- is a sensitive tracer of the dark matter halo mass function (HMF). The $\Lambda$ cold dark matter model…
Analyses of QSO absorption lines are showing that HI content has evolved over the redshift range z=5 to z= 0. The 21cm line measurements of the z=0 HI content avoid several biases inherent in the absorption line technique, such as the…
We present a sample of low HI mass dwarf galaxies ($M_{\rm HI} < 10^8 M_\odot$) detected by The FAST All Sky HI Survey (FASHI) project. Due to the faint and irregular morphology of these galaxies, the default photometry is often inaccurate.…
The Effelsberg-Bonn HI Survey (EBHIS) covers the whole sky north of Dec(2000) = -5 deg. on a fully sampled angular grid. Using state-of-the-art FPGA-spectrometers we perform a Milky Way and an extragalactic HI survey in parallel. Moreover,…
Future prospects in observational galaxy evolution are reviewed from a personal perspective. New insights will especially come from high-redshift integral field kinematic data and similar low-redshift observations in very large and…