Related papers: HI and OH Absorption toward NGC6240

We present a study, done with the Australian LBA, of HI absorption for two compact radio galaxies (PKS 1549-79 and PKS 1814-63). In both the radio galaxies, the HI appears to give us information about the environment in which the radio…

We present MERLIN observations of Galactic 21-cm HI absorption at an angular resolution of c. 0.1-0.2 arcsec and a velocity resolution of 0.5 km/s, in the direction of three moderately low latitude (-8< b <-12 deg) extragalactic radio…

We present WSRT and VLA radio observations of the neutral hydrogen in the radio galaxy Coma A. We detect extended HI absorption against both radio lobes of Coma A, at distances of about 30 kpc from the centre. Coma A is the first radio…

We present high-spatial resolution 21-cm HI VLA observations of the radio galaxy 3C305 (z=0.041). These new high-resolution data show that the ~1000 km/s broad HI absorption, earlier detected in low-resolution WSRT observations, is…

B2352+495 is a prototypical example of a Compact Symmetric Object (CSO). It has a double radio lobe symmetrically located with respect to a central flat spectrum radio core (the location of the AGN) and has a physical extent of less than…

H{\sc i} absorption studies of active galaxies enable us to probe their circumnuclear regions and the general interstellar medium, and study the supply of gas which may trigger the nuclear activity. In this paper, we investigate the…

We present the detection, performed with the Westerbork Synthesis Radio Telescope (WSRT) and the Karl Jansky Very Large Array (VLA), of a fast HI 21-cm outflow in the ultra-luminous infrared galaxy Mrk 231. The outflow is observed as…

We make a comprehensive study of HI absorption toward HII regions located within Galactic longitudes less than 10 degrees. Structures in the extreme inner Galaxy are traced using the longitude-velocity space distribution of this absorption.…

We report the discovery of three HI absorbers toward low-power radio active galactic nuclei (AGNs) in a pilot HI absorption survey with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). Compared to past studies, FAST…

The hydroxyl radical (OH) is found in various environments within the interstellar medium (ISM) of the Milky Way and external galaxies, mostly either in diffuse interstellar clouds or in the warm, dense environments of newly formed low-mass…

The low frequency radio emission of starburst galaxies is informative, but it can be absorbed in several ways. Most importantly, starburst galaxies are home to many H II regions, whose free-free absorption blocks low frequency radio waves.…

We present VLT-UVES echelle spectroscopy of the HI and CIV absorption in the spatially-extended Lyman-alpha emission around two high-redshift radio galaxies 0200+015 (z=2.23) and 0943-242 (z=2.92). The absorbers in 0943-242 exhibit little…

We present HST/STIS and FUSE spectra of the QSO PG 1211+143 (z_em = 0.081) and a galaxy survey of the surrounding field. This sightline shows two strong intergalactic absorption systems at cz ~ 15,300 and 19,300. This sightline addresses…

HI absorption has been detected with the WSRT against both lobes of the radio galaxy Coma A. This radio galaxy could be expanding in a particularly gas rich environment, perhaps the result from interactions/mergers between the dominant…

We present observations of HI and OVI absorption systems proximate to a galaxy at z_gal = 0.3529. The absorption was detected serendipitously in Cosmic Origins Spectrograph observations of the low-z QSO J0943+0531 (z_qso = 0.564). The data…

We performed VLA observations of the 22 GHz H2O maser emission in the merging galaxy NGC6240, which hosts the well-known double active nuclei. In a previous paper, we reported on the first solid detection of the H2O maser emission in 2001.…

This review summarises what we have learnt in the last two decades based on HI 21-cm absorption observations about the cold interstellar medium (ISM) in the central regions of active galaxies and the interplay between this gas and the…

ISO/LWS grating observations of the ultraluminous infrared galaxy Arp 220 shows absorption in molecular lines of OH, H$_2$O, CH, NH, and NH$_3$, as well as in the [O I] 63 $\mu$m line and emission in the [C II] 158 $\mu$m line. We have…

We present results of an HI study of a complete sample of nearby radio galaxies. Our goal is to investigate whether merger or interaction events could be at the origin of the radio-AGN activity. Around five of our radio galaxies, hosted…

We report the discovery of a further line of sight allowing detection of HeII Ly alpha absorption by the intergalactic medium. A HST/STIS survey of 32 bright z ~ 3 quasars selected from the Hamburg Quasar Surveys yielded one detection…