Proposal code

w071

Proposal title

Multi-Frequency VSOP and VLBA survey for GPS Sources

The

Investigators and their

Affiliations

P.I. Seiji Kameno VSOP Project, NAO Japan
Kiyoaki Wajima VSOP Project, ISAS Japan
Masafumi Imai VSOP Project, NAO Japan
Makoto Inoue VSOP Project, NAO Japan
Satoko Sato VSOP Project, NAO Japan

Proposal Abstract

We propose a VSOP survey at 1.6 and 5 GHz for 19 GPS sources. This confirm that rising spectrum below peak frequency is due to free-free absorption (FFA) by cold dense plasma embedding compact nonage lobes. We already submitted a proposal to VLBA at 8 and 15 GHz for the same samples. Four-frequency survey containing the peak frequency with comparable beam size will provide pc-scale spatial distribution of FFA opacity and peak frequency. Sub-mas resolution at low frequency is crucial to resolve double lobe and detect asymmetry or inhomogeneity of abosorption feature. We expect to classify GPS type 1 and 2, which is associated with Seyfert 1 showing asymmetric FFA like OQ 208 and with Seyfert 2 showing less asymmetry, respectively. Furthermore, distribution of spectral index in lobes may show spectral flattening in working surface where expanding lobes are interacting with ambient gas.

The full Cover Sheets (compressed post-script, typically 50kbytes) can 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.