Proposal code
w513
Proposal title
Free-Free Absorption towards an Active Galaxy NGC 1052
The |
Investigators and their |
Affiliations |
| P.I. |
KAMENO Seiji |
NAO, Japan |
| |
SAWADA-SATOH Satoko |
ISAS, Japan |
| |
INOUE Makoto |
NAO, Japan |
| |
SHEN Zhi-Qiang |
ISAS, Japan |
| |
WAJIMA Kiyoaki |
ISAS, Japan |
Proposal Abstract
We propose coordinated VSOP and VLBA observations at five frequencies (1.6
and 5 GHz with VSOP, and 2.3, 8.4, and 15.4 GHz with VLBA) towards an active
galaxy NGC 1052.
Our previous trichromatic VLBA observations at 2.3, 8.4, and 15.4 GHz
towards this object revealed that the convex spectrum peaked at
GHz-frequency is due to free--free absorption (FFA) rather than synchrotron
self-absorption (SSA).
We discovered that the FFA opacity was concentrated at the contral sub-pc
region.
The asymmetric distribution of the opacity, which does not cover the
approaching jet but does the receding one, implied that a dense plasma torus
perpendicular to the jet is the origin of the FFA.
To confirm this result, five-frequency observations with comparable
resolutions are necessary.
Higher resolution at low frequency is crucial to reveal the density profile
of the torus.
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