Millimeter-Wavelength Signatures of Disk Accretion
First Author:
A.Meredith Hughes
Email: mhughes AT cfa.harvard.edu
Harvard-Smithsonian CfA
60 Garden St.
Cambridge, MA 02138 USA
Coauthors:
Wilner, David, CfA
Andrews, Sean, CfA, Hubble Fellow
Qi, Chunhua, CfA
Cho, Jungyeon, CNU Korea, Wisconsin
Lazarian, Alex, Wisconsin
Marrone, Daniel, KICP, Jansky Fellow
Rao, Ram, ASIAA
Lin, Shin-Yi, ASIAA
Hogerheijde, Michiel, Leiden Observatory
Abstract
We present recent results from the Submillimeter Array that use resolved observations of four nearby disk systems (HD 163296, TW Hydrae, GM Aurigae, and MWC 480) to study signatures of disk accretion. Using 1.3 and 0.87 mm continuum and CO J=3-2 data, we show that a simple model motivated by similarity solutions of the time evolution of accretion disks that includes a tapered exponential edge in the surface density distribution can reconcile the apparent discrepancy between gas and dust outer radii obtained by commonly-used models described by power laws in surface density and temperature. For two systems, we further investigate accretion processes with new observations designed to probe turbulent linewidths and magnetic field structure, the central aspects of alpha-disk models with MRI turbulence: observations of the CO J=3-2 line in the TW Hydrae disk at high spectral resolution (44 m/s) allow us to study disk kinematics at a new level of detail, while spatially resolved 0.87 mm polarimetric observations of the HD 163296 disk allow us to test the first realistic predictions of polarized emission from dust grains aligned by magnetic fields threading the disk.
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