Related papers: Atomic hydrogen in AGB circumstellar environments.…
The paper analyzes the absorption line profile at 21 cm for the hydrogen atom in the interstellar medium. The hydrogen atom is treated as a three-level system illuminated by a powerful light source at neighboring resonances corresponding to…
Within the last 10 years, strong, narrow Na I absorption has appeared at v_sun ~ -38 km/s toward the halo star HD 219188; that absorption has continued to strengthen, by a factor 2-3, over the past three years. The line of sight appears to…
High spectral resolution mid-IR observations of ethylene (C2H4) towards the AGB star IRC+10216 were obtained using the Texas Echelon Cross Echelle Spectrograph (TEXES) at the NASA Infrared Telescope Facility (IRTF). Eighty ro-vibrational…
Different physical processes in galaxy evolution, such as galaxy mergers that lead to coalescence of dual Active Galactic Nuclei (AGN) and outflows emanating from the narrow line region, can leave their imprint on the optical spectra of AGN…
The S-stars have been suggested to be a brief transitional phase as stars evolve from oxygen-rich M-type stars into carbon stars, through the dredge up of carbon from He-shell burning. As possible transition objects, S-stars might help…
Hydrogen gas is the dominant component of the local interstellar medium. However, due to ionization and interaction with the heliosphere, direct sampling of neutral hydrogen in the inner heliosphere is more difficult than sampling the local…
We use VLTI/GRAVITY near-infrared interferometry measurements of 8 bright, Type 1 AGN to study the size and structure of hot dust heated by the central engine. We partially resolve each source, and report Gaussian FWHM sizes in the range…
Context. Neutral atomic hydrogen (HI) absorption lines can be used to probe the cold neutral medium (CNM) at high Galactic latitudes. Cold HI with a significant optical depth from the GASKAP-HI survey is found to be located predominantly if…
The nearby radio galaxy 3C293 is one of a small group of objects where extreme outflows of neutral hydrogen have been detected. However, due to the limited spatial resolution of previous observations, the exact location of the outflow was…
We report a uGMRT detection of HI 21-cm absorption associated with the radio source 8C 0604+728, at $z = 3.52965$. The source is at the highest redshift at which associated HI 21-cm absorption has been discovered to date, surpassing earlier…
The aim of this study is to constrain the dynamics, structure and feeding of the compact nucleous of NGC4418, and to reveal the nature of the main hidden power source: starburst or AGN. We obtained high spatial resolution observations of…
There is evidence in 21cm HI emission for voids several kpc in size centered approximately on the Galactic centre, both above and below the Galactic plane. These appear to map the boundaries of the Galactic nuclear wind. An analysis of HI…
Prediction of the soft X-ray absorption along lines of sight through our Galaxy is crucial for understanding the spectra of extragalactic sources, but requires a good estimate of the foreground column density of photoelectric absorbing…
The Lockman Hole is well known as the region with the lowest neutral atomic hydrogen colum density on the entire sky. We present an analysis of the soft X-ray background radiation towards the Lockman Hole using ROSAT all-sky survey data.…
The central arcminute of the Perseus cooling flow galaxy, NGC 1275, has been mapped with the JCMT in 12CO(2-1) at 21 arcsec resolution, with detections out to at least 36 arcsec (12 kpc). Within the limits of the resolution and coverage,…
The chemical composition of stellar photospheres in mass-transferring binary systems is a precious diagnostic of the nucleosynthesis processes that occur deep within stars, and preserves information on the components history. The binary…
We observed the high-mass star-forming region G176.51+00.20 using the Five-hundred-meter Aperture Spherical radio Telescope (FAST) with the 19-beam tracking observational mode. This is a pilot work of searching for neutral stellar winds…
We present observations and models of the kinematics and distribution of neutral hydrogen (HI) in the superthin galaxy FGC 1440 with an optical axial ratio $a/b = 20.4$. Using the Giant Meterwave Radio telescope (GMRT), we imaged the galaxy…
We present MERLIN observations of the continuum (both 1.6 and 5 GHz) and OH maser emission towards Arp220. the correct spatial configuration of the various componnents of the galaxy is revealed. In the eastern component the masers are shown…
Simulations predict that circumgalactic hydrogen gas surrounding massive ($M_{\rm{halo}}^{z=1}=10^{12}-10^{13}\ M_{\odot}$) galaxies at $z\sim4$ may be predominantly neutral, and could produce damped Ly$\alpha$ absorbers (DLAs) along…