Proposal code
w023
Proposal title
TESTING THE SUB-PC ACCRETION DISK HYPOTHESIS FOR NGC 4261
The |
Investigators and their |
Affiliations |
| P.I. |
Dayton L.Jones |
Jet Propulsion Laboratory, Caltech, USA |
| |
Ann E.Wehrle |
Infrared Processing & Analysis Center, Caltech, USA |
Proposal Abstract
We propose to image the central region of NGC 4261 (3C270) with VSOP at 5 GHz
to determine the width of a gap in emission seen on the counterjet side of
the radio core, and thereby test the hypothesis that this gap is caused by
free-free absorption in a nearly edge-on inner accretion disk. Ground-based
images at 8, 22, and 43 GHz show that the
apparent depth of this feature does not decrease with increasing frequency
as expected if it is caused by free-free absorption.
A possible reason for this is that the true width
and depth of the feature is unresolved with ground-based VLBI at lower
frequencies. Higher angular resolution at (nearly) the same frequency is
the most direct way to test this. We also propose to make an image
at 1.6 GHz to compare with ground-based 5 & 8 GHz images.
Comparable resolution images at these frequencies will provide
a better measurement of the electron density distribution if the disk
hypothesis is correct.
The full Cover Sheets
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be retrieved. Note that many proposals were reduced in extent by the
Scientific Review Committee (e.g. by reducing the number of
experiments), however the Cover Sheets contain the full proposal as
submitted. Also note that AO2 proposals were submitted in May 1998,
and information such as affiliations and contact details has
changed for some proposers since that time. The Cover Sheets (and the
details on this page, which were derived from the Cover Sheets) may
therefore have changed.