Related papers: Massive Accretion Disks
Arp 220 is the nearest ULIRG; it shows evidence of 100 pc-scale molecular outflows likely connected with galaxy-scale outflows traced by ionised and neutral gas. The two highly obscured nuclei of Arp 220 are the site of intense star…
The gas and dust are spatially segregated in protoplanetary disks due to the vertical settling and radial drift of large grains. A fuller accounting of the mass content and distribution in disks therefore requires spectral line…
We present new determinations of disk surface density, independent of an assumed dust opacity, for a sample of 7 bright, diverse protoplanetary disks using measurements of disk dust lines. We develop a robust method for determining the…
The 500 central pc of the Galaxy (hereafter GC) exhibit a widespread gas component with a kinetic temperature of 100-200 K. The bulk of this gas is not associated to the well-known thermal radio continuum or far infrared sources like Sgr A…
The 25 years following the serendipitous discovery of megamasers have seen tremendous progress in the study of luminous extragalactic H$_2$O emission. Single-dish monitoring and high resolution interferometry have been used to identify…
We model gas and dust emission from regions 0.3-20 AU from a central low mass star in intermediate-aged(~10Myr) disks with optically thin dust. The models treat thermal balance and chemistry self-consistently and calculate the vertical…
We report single-dish multi-transition measurements of the 12^CO, HCN, and HCO^+ molecular line emission as well as HNC J=1-0 and HNCO in the two ultraluminous infra-red galaxies Arp220 and NGC6240. Using this new molecular line inventory,…
A supermassive black hole SgrA* with the mass ~4x10^6 Msun resides at the centre of our galaxy. Building up such a massive black hole within the ~10^10 year lifetime of our galaxy would require a mean accretion rate of ~4x10^-4 Msun/yr. At…
The cold molecular gas in the circumnuclear disk (CND) of radio galaxies provides critical information for understanding the mass accretion onto active galactic nuclei. We present the first detection and maps of HCN J=1-0 and HCO+ J=1-0…
We study dust concentration in axisymmetric gas rings in protoplanetary disks. Given the gas surface density, we derived an analytical total dust surface density by taking into account the differential concentration of all the grain sizes.…
It is widely believed that stellar-mass black holes (sMBHs) exist within the accretion disks of active galactic nuclei (AGN), forming a distinct population termed ``accretion-modified star" (AMS). Gas from the dense disk accretes onto these…
We report first results from a large project to measure black hole (BH) mass in high accretion rate active galactic nuclei (AGNs). Such objects may be different from other AGNs in being powered by slim accretion disks and showing saturated…
Constraining dust properties of planet-forming disks via high angular resolution observations is fundamental to understanding how solids are trapped in substructures and how dust growth may be favored or accelerated therein. We use ALMA…
We present ~2'' resolution CO(3-2), HCO+(4-3) and 880micron continuum images of the luminous infrared galaxy NGC6240 obtained at the Submillimeter Array. We find that the spatially resolved CO(3-2), HCO+(4-3) and the 880micron emission…
High resolution (lambda / Delta-lambda = 50,000) K-band spectra of massive, embedded, young stellar objects are presented. The present sample consists of four massive young stars located in nascent clusters powering Galactic giant H II…
The disks that surround young stars are mostly composed of molecular gas, which is harder to detect and interpret than the accompanying dust. Disk mass measurements have therefore relied on large and uncertain extrapolations from the dust…
Transition disks with large inner dust cavities are thought to host massive companions. However, the disk structure inside the companion orbit and how material flows toward an actively accreting star remain unclear. We present a high…
(Abridged) Infrared high-resolution imaging and interferometry have shown that the dust distribution is frequently elongated along the polar direction of an AGN. To explain these findings, we developed a model scenario for the inner ~30 pc…
We study the accretion of dust particles of various sizes onto embedded massive gas giant planets, where we take into account the structure of the gas disk due to the presence of the planet. The accretion rate of solids is important for the…
We consider the structure of self-gravitating marginally stable accretion disks in galactic centers in which a small fraction of the disk mass has been converted into proto-stars. We find that proto-stars accrete gaseous disk matter at…