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We present a study of 16 H   i -detected galaxies found in 178 h 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 per cent of the total frequency coverage and 18 per  cent 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 extract the 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. [ABSTRACT FROM AUTHOR]

We test models of starburst driven outflows using observations of the 22.2 GHz H2O and 36.2 GHz class I CH3OH maser lines. We have observed the starburst galaxy NGC 253 using the Karl G. Jansky Very Large Array. We present evidence for entrainment of star-forming dense-molecular gas in the outflow of NGC 253. We also show that H2O masers are associated with forming super star clusters and not with supernova remnants. We detect four new 36 GHz CH3OH masers in the central kpc and show possible evidence for a star-formation origin of two class I CH3OH masers. Such high resolution observations are essential for understanding the origin of these masers. [ABSTRACT FROM AUTHOR]

We report the discovery of a grand-design spiral galaxy associated with a double-lobed radio source. J1649+2635 (z = 0.0545) is a red spiral galaxy with a prominent bulge that it is associated with a L1.4 GHz ∼ 1024 W Hz−1 double-lobed radio source that spans almost 100 kpc. J1649+2635 has a black hole mass of MBH ~ 3-7 × 108 M⊙ and SFR ~ 0.26-2.6 M⊙yr−1. The galaxy hosts an ~96 kpc diffuse optical halo, which is unprecedented for spiral galaxies. We find that J1649+2635 resides in an overdense environment with a mass of Mdyn=7.7+7.9−4.3×1013 M⊙, likely a galaxy group below the detection threshold of the ROSAT All-Sky Survey. We suggest one possible scenario for the association of double-lobed radio emission from J1649+2635 is that the source may be similar to a Seyfert galaxy, located in a denser-than-normal environment. The study of spiral galaxies that host large-scale radio emission is important because although rare in the local Universe, these sources may be more common at high redshifts. [ABSTRACT FROM AUTHOR]

We report results from a deep search for redshifted HI 21 cm absorption from eight damped Lyman a absorbers (DLAs) detected in our earlier optical survey for DLAs towards radio-loud quasars. HI 21 cm absorption was detected from the z = 2.192 DLA towards TXS 2039+187, only the sixth case of such a detection at z > 2, while upper limits on the HI 21 cm optical depth were obtained in six other DLAs at z > 2. Our detection of HI 21 cm absorption in the eighth system, at z=2.289 towards TXS 0311+430, has been reported earlier. We also present high spatial resolution images of the background quasars at frequencies close to the redshifted HI 21 cm line frequency, allowing us to estimate the covering factor of each DLA, and then determine its spin temperature Ts. For three non-detections of HI 21 cm absorption, we obtain strong lower limits on the spin temperature, Ts ≥ 790 K, similar to the bulk of the high-z DLA population; three other DLAs yield weak lower limits, Ts > 140-400 K. However, for the two DLAs with detections of HI 21 cm absorption, the derived spin temperatures are both low, Ts = (160 ± 35) × (f/0.35) K for the z = 2.192 DLA towards TXS 2039+187 and Ts = (72 ± 18) × (f/0.52) K for the z = 2.289 DLA towards TXS 0311+430. These are the first two DLAs at z > 1 with Ts values comparable to those obtained in local spiral galaxies. Based on the observed correlations between spin temperature and metallicity and velocity spread and metallicity in DLAs, we suggest that the hosts of the two absorbers are likely to be massive, high-metallicity galaxies. [ABSTRACT FROM AUTHOR]

We report results from a deep search for redshifted H i 21 cm absorption from eight damped Lyman α absorbers (DLAs) detected in our earlier optical survey for DLAs towards radio-loud quasars. H i 21 cm absorption was detected from the z = 2.192 DLA towards TXS 2039+187, only the sixth case of such a detection at z > 2, while upper limits on the H i 21 cm optical depth were obtained in six other DLAs at z > 2. Our detection of H i 21 cm absorption in the eighth system, at z = 2.289 towards TXS 0311+430, has been reported earlier. We also present high spatial resolution images of the background quasars at frequencies close to the redshifted H i 21 cm line frequency, allowing us to estimate the covering factor of each DLA, and then determine its spin temperature Ts. For three non-detections of H i 21 cm absorption, we obtain strong lower limits on the spin temperature, Ts ≳ 790 K, similar to the bulk of the high-z DLA population; three other DLAs yield weak lower limits, Ts > 140–400 K. However, for the two DLAs with detections of H i 21 cm absorption, the derived spin temperatures are both low, Ts = (160 ± 35) × (f/0.35) K for the z = 2.192 DLA towards TXS 2039+187 and Ts = (72 ± 18) × (f/0.52) K for the z = 2.289 DLA towards TXS 0311+430. These are the first two DLAs at z > 1 with Ts values comparable to those obtained in local spiral galaxies. Based on the observed correlations between spin temperature and metallicity and velocity spread and metallicity in DLAs, we suggest that the hosts of the two absorbers are likely to be massive, high-metallicity galaxies. [ABSTRACT FROM PUBLISHER]

ABSTRACT The H i 21-cm absorption optical depth and the N(H i) column density derived from Lyα absorption can be combined to yield the spin temperature ( Ts) of intervening damped Lyα systems (DLAs). Although spin temperatures have been determined for samples of DLAs with zabs < 0.6 and zabs > 1.7, the intermediate regime currently contains only two Ts measurements, leading to a 'redshift desert' that spans 4 Gyr of cosmic time. To connect the low- and high-redshift regimes, we present observations of the Lyα line of six 0.6 < zabs < 1.7 H i 21-cm absorbers. The data set is complemented by both low-frequency Very Long Baseline Array observations (to derive the absorber covering factor, f) and optical echelle spectra from which metal abundances are determined. Our data set therefore not only offers the largest statistical study of H i 21-cm absorbers to date, and bridges the redshift desert, but is also the first to use a fully f-corrected data set to look for metallicity-based trends. The metallicities of H i 21-cm absorbers are consistent with those of optically selected DLAs at the same redshift. In agreement with trends found in Galactic sightlines, we find that the lowest column density absorbers tend to be dominated by warm gas. In the DLA regime, spin temperatures show a wider range of values than Galactic data, as may be expected in a heterogeneous galactic population. However, we find that low-metallicity DLAs are dominated by small cold gas fractions and only absorbers with relatively high metallicities exhibit significant fractions of cold gas. Using a compilation of H i 21-cm absorbers which are selected to have covering-factor-corrected spin temperatures, we confirm an anticorrelation between metallicity and Ts at 3.4σ significance. Finally, one of the DLAs in our sample is a newly discovered H i 21-cm absorber (at zabs= 0.602 towards J1431+3952), which we find to have the lowest f-corrected spin temperature yet reported in the literature: K. The observed distribution of Ts and metallicities in DLAs and the implications for understanding the characteristics of the interstellar medium in high-redshift galaxies are discussed. [ABSTRACT FROM AUTHOR]

ABSTRACT The H i 21-cm absorption optical depth and the N(H i) column density derived from Lyα absorption can be combined to yield the spin temperature ( Ts) of intervening damped Lyα systems (DLAs). Although spin temperatures have been determined for samples of DLAs with zabs < 0.6 and zabs > 1.7, the intermediate regime currently contains only two Ts measurements, leading to a 'redshift desert' that spans 4 Gyr of cosmic time. To connect the low- and high-redshift regimes, we present observations of the Lyα line of six 0.6 < zabs < 1.7 H i 21-cm absorbers. The data set is complemented by both low-frequency Very Long Baseline Array observations (to derive the absorber covering factor, f) and optical echelle spectra from which metal abundances are determined. Our data set therefore not only offers the largest statistical study of H i 21-cm absorbers to date, and bridges the redshift desert, but is also the first to use a fully f-corrected data set to look for metallicity-based trends. The metallicities of H i 21-cm absorbers are consistent with those of optically selected DLAs at the same redshift. In agreement with trends found in Galactic sightlines, we find that the lowest column density absorbers tend to be dominated by warm gas. In the DLA regime, spin temperatures show a wider range of values than Galactic data, as may be expected in a heterogeneous galactic population. However, we find that low-metallicity DLAs are dominated by small cold gas fractions and only absorbers with relatively high metallicities exhibit significant fractions of cold gas. Using a compilation of H i 21-cm absorbers which are selected to have covering-factor-corrected spin temperatures, we confirm an anticorrelation between metallicity and Ts at 3.4σ significance. Finally, one of the DLAs in our sample is a newly discovered H i 21-cm absorber (at zabs= 0.602 towards J1431+3952), which we find to have the lowest f-corrected spin temperature yet reported in the literature: K. The observed distribution of Ts and metallicities in DLAs and the implications for understanding the characteristics of the interstellar medium in high-redshift galaxies are discussed. [ABSTRACT FROM AUTHOR]