Related papers: Atomic Gas in Debris Discs
Mechanisms such as collisions of rocky bodies or cometary activity give rise to dusty debris disks. Debris disks trace the leftover building blocks of planets, and thus also planetary composition. HD 172555, a stellar twin of beta Pic,…
The disk around AU Microscopii, an M1 star in the Beta Pictoris Moving Group, is extraordinarily well-suited for comparison to the Beta Pic debris disk (type A5V). We use far-UV absorption spectroscopy of AU Mic to probe its edge-on disk…
We report the results of a search for gas phase atomic metals in the circumstellar envelope of the AGB carbon star IRC+10216. The search was made using high resolution (R=50000) optical absorption spectroscopy of a backgound star that…
Debris discs around main sequence stars have been extensively characterised from infrared to millimetre wavelengths through imaging, spectroscopic, and total intensity (scattered light and/or thermal emission) measurements. Polarimetric…
IRAS~04158+2805 has long been thought to be a very low mass T-Tauri star (VLMS) surrounded by a nearly edge-on, extremely large disc. Recent observations revealed that this source hosts a binary surrounded by an extended circumbinary disc…
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…
Beta Pictoris is a young planetary system surrounded by a debris disk of dust and gas. The gas source of this disk could be exocomets (or 'falling and evaporating bodies', FEBs), which produce refractory elements (Mg, Ca, Fe) through…
Absorption-selected galaxies offer an effective way to study low-mass galaxies at high redshift. However, the physical properties of the underlying galaxy population remains uncertain. In particular, the multiphase circum-galactic medium is…
Circumstellar debris disks older than a few Myr should be largely devoid of primordial gas remaining from the protoplanetary disk phase. Tracing the origin of observed atomic gas in Keplerian rotation in the edge-on debris disk surrounding…
The A star 49 Ceti, at a distance of 61 pc, is unusual in retaining a substantial quantity of molecular gas while exhibiting dust properties similar to those of a debris disk. We present resolved observations of the disk around 49 Ceti from…
The 30 Myr old A3-type star HD 21997 is one of the two known debris dust disks having a measurable amount of cold molecular gas. With the goal of understanding the physical state, origin, and evolution of the gas in young debris disks, we…
We consider the peculiarities of the optical spectra of far evolved stars with circumstellar gaseous-dusty envelopes: the time variability of the absorption-emission profiles of the H$\alpha$ line, the presence of stationary emission and…
Recent targeted studies of associated HI absorption in radio galaxies are starting to map out the location, and potential cosmological evolution, of the cold gas in the host galaxies of Active Galactic Nuclei (AGN). The observed 21 cm…
We describe the dynamical, photometric, and spectroscopic data available for stars targeted by Spitzer and Herschel to search for cold circumstellar dust emission from debris disks, a collection that we name the Cold Debris Disk Surveys…
We present far-IR/sub-mm imaging and spectroscopy of 49 Ceti, an unusual circumstellar disk around a nearby young A1V star. The system is famous for showing the dust properties of a debris disk, but the gas properties of a low-mass…
High quality infrared spectra of active galaxies including the stellar absorption features of Si at 1.59 um, CO(6,3) at 1.62 um, and CO(2,0) at 2.29 um are used to measure the stellar mass to light ratio at 1.65 um (M_H/L) and investigate…
Gas-rich primordial disks and tenuous gas-poor debris disks are usually considered as two distinct evolutionary phases of the circumstellar matter. Interestingly, the debris disk around the young main-sequence star 49 Ceti possesses a…
We present a systematic study of the multi-phase interstellar gas in the Inner Galaxy using HST/STIS absorption spectroscopy of 16 massive stars located at spectroscopic distances between 1.3 and 10 kpc in the region $-30^\circ\lesssim l…
We have observed 22 Lindroos stars with SCUBA on the JCMT to search for evidence of dust discs. Stars in this sample are the less massive companions of B-type primaries and have ages of 10-170Myr. Dust was detected around three of these…
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…