Related papers: The HI Environment of Nearby Lyman-alpha Absorbers

Spectra of the QSO pair Q0307-195A,B have been obtained in the Ly-alpha Forest (3660 - 3930 A) and C IV (4720 - 4850 A) regions with a FWHM resolution between 0.7 and 0.5 A. 46 lines have been detected in the spectrum of object A while 36…

We present 1.4 GHz HI absorption line observations towards the starburst in NGC2146, made with the VLA and MERLIN. The HI gas has a rotating disk/ring structure with column densities between 6 and 18 x 10(21) atoms cm(-2). The HI absorption…

We have serendipitously detected a strong O VI-bearing Lyman limit system at z_abs = 0.3558 toward the QSO J1009+0713 (z_em = 0.456) in our survey of low-redshift galaxy halos with the Hubble Space Telescope's Cosmic Origins Spectrograph.…

We report on the discovery of HI in absorption toward the gigamaser galaxy TXS2226-184 using the VLA. The absorption appears to consist of two components -- one with a width of 125 km/s, and one broader (420 km/s), both toward the compact…

We have studied a spectrum of Q0122+0338 (z = 1.202) obtained by the FOS on board HST. We present the analysis of three associated absorption systems at z = 1.207, 1.199 and 1.166. The most complex of these at z = 1.207 shows strong…

We report the emergence of a new HI 21-cm absorption at z_abs = 1.172635 in the damped Lyman-alpha absorber (DLA) towards the gamma-ray blazar PKS 2355-106 (z_em~1.639) using science verification observations (June 2020) from the MeerKAT…

We present composite spectra constructed from a sample of 242,150 Lyman-alpha (Lya) forest absorbers at redshifts 2.4<z<3.1 identified in quasar spectra from the Baryon Oscillation Spectroscopic Survey (BOSS) as part of Data Release 9 of…

We report on the detection of low-column density neutral hydrogen clumps in the halo of the Milky Way. Using high-resolution (FWHM~7 km/s) optical spectra obtained with the VLT/UVES spectrograph we detect narrow interstellar absorption by…

The neutral atomic gas content of galaxies is usually studied in the HI 21cm emission line of hydrogen. However, at higher redshifts, we need very deep integrations to detect HI emission. The HI absorption does not suffer from this…

Lyman- and Werner-band absorption of molecular hydrogen (H$_2$) is detected in $\sim$50% of low redshift ($z<1$) DLAs/sub-DLAs with $N$(H$_2$) > 10$^{14.4}$ cm$^{-2}$. However the true origin(s) of the H$_2$ bearing gas remain elusive. Here…

Using data from the Southern Galactic Plane Survey (SGPS) we analyze an HI self-absorption cloud centered on l = 318.0 deg, b = -0.5 deg, and velocity, v = -1.1 km/s. The cloud was observed with the Australia Telescope Compact Array (ATCA)…

We present an HI 21cm absorption study of a sample of 26 radio-loud active galactic nuclei (AGN) at $0.25 < z < 0.4$ carried out with the Karl G. Jansky Very Large Array. Our aim was to study the rate of incidence of HI in various classes…

We present a detailed study of the emission from a z = 2.35 galaxy that causes damped Lyman-alpha absorption in the spectrum of the background QSO, SDSS J 2222-0946. We present the results of extensive analyses of the stellar continuum…

The spatial and kinematic distribution of warm gas in and around the Coma Cluster is presented through observations of Lyman-alpha absorbers using background QSOs. Updates to the Lyman-alpha absorber distribution found in Yoon et al. (2012)…

Using long-slit optical spectra obtained with the 2-m telescope at IUCAA Girawali Observatory, we show that the radio source J094221.98+062335.2 (z=0.123) is associated with a galaxy pair undergoing a major merger. Its companion is a normal…

We report the discovery of an O VI absorption system at z(abs) = 0.14232 in a high resolution FUV spectrum of PG0953+415 obtained with the Space Telescope Imaging Spectrograph (STIS). Both lines of the O VI 1032, 1038 doublet and…

We investigate the physical state of HI absorbing gas at low redshift (z = 0.25) using a subset of cosmological, hydrodynamic simulations from the OWLS project, focusing in particular on broad (b_HI > 40 km/s) HI Lyman-Alpha absorbers…

Using galaxies as background light sources to map intervening Lya absorption is a novel approach to study the interplay among galaxies, the circum-galactic medium (CGM), and the intergalactic medium (IGM). Introducing a new measure of z =…

We conducted a HI 21cm absorption study of a sample of 147 nearby (z < 0.1) low-power radio sources with $10\,\mathrm{mJy} < S_{1.4\,\mathrm{GHz}} < 30\,\mathrm{mJy}$ and $\log(P_{1.4\,\mathrm{GHz}}/\mathrm{W\,Hz^{-1}}) = 20.5-23.7$, using…

We detect 21-cm emission from the Low Surface Brightness (LSB) galaxy SBS 1543+593, which gives rise to a Damped Lyman-alpha (DLA) absorption line in the spectrum of the background QSO HS 1543+5921 (z=0.807). We obtain an accurate measure…