We present neutral hydrogen (H i) and ionized hydrogen (H α) observations of 10 galaxies out to a redshift of 0.1. The H i observations are from the first epoch (178 h) of the COSMOS H i Large Extragalactic Survey (CHILES). Our sample is H i biased and consists of 10 late-type galaxies with H i masses that range from 1.8 × 107 M⊙ to 1.1 × 1010 M⊙. We find that although the majority of galaxies show irregularities in the morphology and kinematics, they generally follow the scaling relations found in larger samples. We find that the H i and H α velocities reach the flat part of the rotation curve. We identify the large-scale structure in the nearby CHILES volume using DisPerSE with the spectroscopic catalogue from SDSS. We explore the gaseous properties of the galaxies as a function of location in the cosmic web. We also compare the angular momentum vector (spin) of the galaxies to the orientation of the nearest cosmic web filament. Our results show that galaxy spins tend to be aligned with cosmic web filaments and show a hint of a transition mass associated with the spin angle alignment.

We demonstrate that the Discrete Persistent Source Extractor (DisPerSE) can be used with spectroscopic redshifts to define the cosmic web and its distance to galaxies in small area deepfields. Here we analyze the use of DisPerSE to identify structure in observational data. We apply DisPerSE to the distribution of galaxies in the COSMOS field and find the best parameters to identify filaments. We compile a catalog of 11500 spectroscopic redshifts from the Galaxy and Mass Assembly (GAMA) G10 data release. We analyze two-dimensional slices, extract filaments and calculate the distance for each galaxy to its nearest filament. We find that redder and more massive galaxies are closer to filaments. To study the growth of galaxies across cosmic time, and environment, we are carrying out an HI survey covering redshifts z = 0 -0.45, the COSMOS HI Large Extragalactic Survey (CHILES). In addition we present the predicted HI mass fraction as a function of distance to filaments for the spectroscopically known galaxies in CHILES. Lastly, we discuss the cold gas morphology of a few individual galaxies and their positions with respect to the cosmic web. The identification of the cosmic web, and the ability of CHILES to study the resolved neutral hydrogen morphologies and kinematics of galaxies, will allow future studies of the properties of neutral hydrogen in different cosmic web environments across the redshift range z = 0.1 -0.45.

We present a study of 16 H i-detected galaxies found in 178 hours of observations from Epoch 1 of the COSMOS H i Large Extragalactic Survey (CHILES). We focus on two redshift ranges between 0.108 ≤ z ≤ 0.127 and 0.162 ≤ z ≤ 0.183 which are among the worst affected by radio frequency interference (RFI). While this represents only 10% of the total frequency coverage and 18% of the total expected time on source compared to what will be the full CHILES survey, we demonstrate that our data reduction pipeline recovers high quality data even in regions severely impacted by RFI. We report on our in-depth testing of an automated spectral line source finder to produce H i total intensity maps which we present side-by-side with significance maps to evaluate the reliability of the morphology recovered by the source finder. We recommend that this become a common place manner of presenting data from upcoming H i surveys of resolved objects. We use the COSMOS 20k group catalogue, and we extract filamentary structure using the topological DisPerSE algorithm to evaluate the H i morphology in the context of both local and large-scale environments and we discuss the shortcomings of both methods. Many of the detections show disturbed H i morphologies suggesting they have undergone a recent interaction which is not evident from deep optical imaging alone. Overall, the sample showcases the broad range of ways in which galaxies interact with their environment. This is a first look at the population of galaxies and their local and large-scale environments observed in H i by CHILES at redshifts beyond the z = 0.1 Universe.

We present MeerKAT H i observations of six jellyfish candidate galaxies (JFCGs) in the galaxy cluster, A2626. Two of the six galaxies JW100 and JW103, that were identified as JFCGs from B-band images, are confirmed as jellyfish galaxies (JFGs). Both of the JFGs have low H i content, reside in the cluster core, and move at very high velocities (∼ 3σcl). The other JFCGs, identified as non-jellyfish galaxies, are H i rich, with H i morphologies revealing warps, asymmetries, and possible tidal interactions. Both the A2626 JFGs and three other confirmed JFGs from the GASP sample show that these galaxies are H i stripped but not yet quenched. We detect H i, Hα, and CO(2-1) tails of similar extent (∼ 50 kpc) in JW100. Comparing the multi-phase velocity channels, we do not detect any H i or CO(2-1) emission in the northern section of the tail where Hα emission is present, possibly due to prolonged interaction between the stripped gas and the ICM. We also observe an anti-correlation between H i and CO(2-1), which hints at an efficient conversion of H i to H2 in the southern part of the tail. We find that both RPS and H i-to-H2 conversion are significant depletion channels for atomic gas. H i-to-H2 conversion is more efficient in the disc than in the tail.