Related papers: Atomic hydrogen in AGB circumstellar environments.…
We analyze line-of-sight atomic hydrogen (HI) line profiles of 31 nearby, low-mass galaxies selected from the Very Large Array - ACS Nearby Galaxy Survey Treasury (VLA-ANGST) and The HI Nearby Galaxy Survey (THINGS) to trace regions…
We present Very Long Baseline Array (VLBA) HI absorption observations of the core region of the powerful radio galaxy Cygnus A. These data show both broad (FWHM = 231 \pm 21 km/s) and narrow (FWHM <30 km/s) velocity width absorption…
This paper presents interferometric and single-dish CO observations along with HI data obtained for the oxygen-rich semi-regular variable RS Cnc, in order to probe its circumstellar environment at different scales. With the Plateau de Bure…
We present new ATCA 21-cm line observations of the neutral hydrogen in the nearby radio galaxy Centaurus A. We image in detail (with a resolution down to 7", ~100pc) the distribution of HI along the dust lane. Our data have better velocity…
S-type AGB stars have a C/O ratio which suggests that they are transition objects between oxygen-rich M-type stars and carbon-rich C-type stars. As such, their circumstellar compositions of gas and dust are thought to be sensitive to their…
Spatial and kinematical correlations between HI and CO (2-1) emission of the southern spiral galaxy NGC4945 are studied with a common angular (23 arcsec) and velocity resolution (7 km/s). The 21cm continuum emission is also observed. The HI…
We report on atomic gas (HI) and molecular gas (as traced by CO(2-1)) redshifted absorption features toward the nuclear regions of the closest powerful radio galaxy, Centaurus A (NGC 5128). Our HI observations using the Very Long Baseline…
We present an analysis of the HI absorption in a sample of 101 flux-selected radio AGN (S_1.4 GHz > 50 mJy) observed with the Westerbork Synthesis Radio Telescope (WSRT). HI absorption is detected in 32 galaxies, showing a broad variety of…
CONTEXT: Asymptotic giant branch (AGB) stars are in one of the latest evolutionary stages of low to intermediate-mass stars. Their vigorous mass loss has a significant effect on the stellar evolution, and is a significant source of heavy…
We report the preliminary results of a survey for water vapor in a sample of eight C stars with large mid-IR continuum fluxes: V384 Per, CIT 6, V Hya, Y CVn, IRAS 15194-5115, V Cyg, S Cep, and IRC+40540. This survey, performed using the…
We have mapped the emission from atomic hydrogen at 21 cm from the galaxy NGC 3783 with the Australia Telescope Compact Array. Our main results are: a) the HI morphology is irregular and perturbed, gathered in three blobs apparently…
We report the detection of 21-cm line emission from H I in the planetary nebula NGC 7293 (the Helix). The observations, made with the Very Large Array, show the presence of a ring of atomic hydrogen that is associated with the outer portion…
We present high resolution (R ~ 4 km/s) absorption measurements of the interstellar NaI and CaII lines measured towards 14 early-type stars of distance 123 pc - 1650 pc, located in the direction of the Ara OB1 stellar cluster. The line…
Cold, neutral interstellar gas, the reservoir for star formation, is traced through the absorption of the 21-centimetre continuum radiation by neutral hydrogen (HI). Although detected in one hundred cases in the host galaxies of distant…
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 analyse archival ALMA (Atacama Large Millimeter/submillimeter Array) observations of two molecular line emissions, $^{12}$CO(3-2) and $^{29}$SiO(8-7), from oxygen-rich AGB (Asymptotic Giant Branch) star W Hya. Together with results of…
Recent submillimeter and far-infrared wavelength observations of absorption in the rotational ground-state lines of various simple molecules against distant Galactic continuum sources have opened the possibility of studying the chemistry of…
Aims: By performing a detailed radiative transfer analysis, we determine fractional abundances of circumstellar H2O in the envelopes around six M-type asymptotic giant branch stars. The models are also used to predict H2O spectral line…
Many radio galaxies show the presence of dense and dusty gas near the active nucleus. This can be traced by both 21cm HI absorption and soft X-ray absorption, offering new insight into the physical nature of the circumnuclear medium of…
We use observations of the neutral atomic hydrogen (HI) 21-cm emission line to study the spatial distribution of the HI gas in a 80$\degree\times~$90$\degree$ region of the Galaxy halo. The HI column densities in the range of…