Related papers: Further Observational Evidence for a Critical Ioni…

We present near infrared ISAAC VLT observations of nine (0.01<z<0.06) Active Galactic Nuclei selected from the Hamburg/ESO Survey and the Veron-Cetty & Veron catalog. Hydrogen recombination lines Pa$\alpha$ and Br$\gamma$ are observed in…

We report the discovery of a strong CIV 1548,1550 absorption system at z_abs = 5.7238 in the near-infrared spectrum (J-band) of the z_em = 6.28 QSO SDSS J1030+0524. These observations, obtained with the Infrared Spectrometer And Array…

In a previous paper we presented the results of applying machine learning to classify whether an HI 21-cm absorption spectrum arises in a source intervening the sight-line to a more distant radio source or within the host of the radio…

The star-forming reservoir in the distant Universe can be detected through HI 21-cm absorption arising from either cool gas associated with a radio source or from within a galaxy intervening the sight-line to the continuum source. In order…

We have used the 610 MHz receivers of the Giant Metrewave Radio Telescope (GMRT) to detect associated HI 21cm absorption from the $z = 1.2230$ blazar TXS1954+513. The GMRT HI 21cm absorption is likely to arise against either the…

We present the results of HI and OH absorption measurements towards a sample of radio sources using the Arecibo 305-m telescope and the GMRT. In total, 27 radio sources were searched for associated 21-cm HI absorption. One totally new HI…

In this letter, 21 cm intensity maps acquired at the Green Bank Telescope are cross-correlated with large-scale structure traced by galaxies in the WiggleZ Dark Energy Survey. The data span the redshift range 0.6 < z < 1 over two fields…

In a pilot search for high-redshift radio QSOs, we have obtained spectra of 55 FIRST sources (S(1.4GHz) > 1 mJy) with very red (O-E > 3) starlike optical identifications. 10 of the candidates are QSOs with redshifts 3.6 < z < 4.4 (4…

We have searched for HI 21cm absorption toward the two brightest radio AGN at high redshift, J0924--2201 at $z = 5.20$, and J0913+5919 at $z=5.11$, using the Giant Meter Wave Radio Telescope (GMRT). These data set a 3$\sigma$ upper limit to…

This is the second in a series of papers presenting observations and results for a sample of 76 ultra-steep-spectrum (USS) radio sources in the southern hemisphere designed to find galaxies at high redshift. Here we focus on the optical…

We present analysis of two O VI absorbers at redshift z_{abs} = 0.227, detected in the spectra of two closely spaced QSO sightlines (Q 0107-025 A and B), observed with the Cosmic Origins Spectrograph (COS) on board the Hubble Space…

This review summarizes recent studies of the cold neutral hydrogen gas associated with galaxies probed via the HI 21-cm absorption line. HI 21-cm absorption against background radio-loud quasars is a powerful tool to study the neutral gas…

At present neutral atomic hydrogen (HI) gas in galaxies at redshifts above $z \sim 0.3$ (the extent of 21-cm emission surveys in individual galaxies) and below $z \sim 1.7$ (where the Lyman-$\alpha$ line is not observable with ground-based…

We report measurements of the carbon monoxide ground state rotational transition (12C16O J = 1--0) with the Zpectrometer ultra-wideband spectrometer on the 100-m diameter Green Bank Telescope. The sample comprises 11 galaxies with redshifts…

We have recently discovered five Lyman continuum leaking galaxies at z~0.3, selected for their compactness, intense star-formation, and high [OIII]/[OII] ratio (Izotov et al. 2016ab). Here we derive their ionizing photon production…

Rest-frame far-ultraviolet (FUV) observations from JWST are revolutionizing our understanding of the high-z galaxies that drove reionization and the mechanisms by which they accomplished it. To fully interpret these observations, we must be…

We use a wide-field (0.9 square degree) X-ray sample with optical and GALEX ultraviolet observations to measure the contribution of Active Galactic Nuclei (AGNs) to the ionizing flux as a function of redshift. Our analysis shows that the…

We searched for 21-cm absorption associated with the z_abs = 1.3647 absorption system toward PKS 0237-233 using the GMRT. A high quality UVES spectrum shows that C I and C I* are detected at this redshift together with C II*, Mg I, Mg II,…

We present a measurement of the mean intensity of the hydrogen-ionizing background radiation field at low redshift using 906 Ly-alpha absorption lines in 151 quasar spectra from the archives of the Faint Object Spectrograph on the Hubble…

We present initial results of a survey for star-forming galaxies in the redshift range 3.8 < z < 4.5. This sample consists of a photometric catalog of 244 galaxies culled from a total solid angle of 0.23 square degrees to an apparent…