Discovery of Candidate H$_2$O Disk Masers in AGN and Estimations of Centripetal Accelerations (2009)
Greenhill, Lincoln J., Kondratko, Paul T., Moran, James M., Tilak, Avanti
Based on spectroscopic signatures, about one-third of known H$_2$O maser sources in active galactic nuclei (AGN) are believed to arise in highly inclined accretion disks around central engines. These...
The Parsec-scale Accretion Disk in NGC 3393 (2008)
Kondratko, Paul T., Greenhill, Lincoln J., Moran, James M.
We present a Very Long Baseline Interferometry image of the water maser emission in the nuclear region of NGC3393. The maser emission has a linear distribution oriented at a position angle of $\sim...
Kondratko, Paul T., Greenhill, Lincoln J., Moran, James M.
We report the discovery of water maser emission in five active galactic nuclei (AGN) with the 100-m Green Bank Telescope (GBT). The positions of the newly discovered masers, measured with the VLA,...
Probing the Magnetic Field at Sub-Parsec Radii in the Accretion Disk of NGC 4258 (2005)
Modjaz, Maryam, Moran, James M., Kondratko, Paul T., Greenhill, Lincoln J.
We present an analysis of polarimetric observations at 22 GHz of the water vapor masers in NGC 4258 obtained with the VLA and the GBT. We do not detect any circular polarization in the spectrum...
Evidence for a Geometrically Thick Self-Gravitating Accretion Disk in NGC 3079 (2004)
Kondratko, Paul T., Greenhill, Lincoln J., Moran, James M.
We have mapped, for the first time, the full velocity extent of the water maser emission in NGC 3079. The largely north-south distribution of emission, aligned with a kpc-scale molecular disk, and...
Using VLBI to Probe the Orion-KL Outflow on AU Scales (2004)
Doeleman, Sheperd S., Lonsdale, Colin J., Kondratko, Paul T., Predmore, C. Read
We present the first contemporaneous 43GHz and 86GHz VLBI images of the v=1 J=2-1 and J=1-0 SiO masers in the Orion-KL nebula. Both maser species exhibit the same general morphology of earlier J=1-0...