KNIFE, KAshima Nobeyama InterFErometer

TL;DR

The paper discusses the development and achievements of the KNIFE project, which connected Kashima and Nobeyama antennas to enable high-sensitivity 43~GHz VLBI observations, marking a significant advancement in radio astronomy technology.

Contribution

Introduction of the first cooled-HEMT 43~GHz receiver and successful VLBI observations at 43~GHz using the Kashima-Nobeyama baseline.

Findings

First fringe detection at 43~GHz in 1989

Highest sensitivity at 43~GHz VLBI at the time

Successful integration of cooled-HEMT receiver in VLBI system

Abstract

By connecting two antennas, Kashima 34~m and Nobeyama 45~m, an east-west baseline of 200~km is formed. At that time, because Nobeyama 45~m had the world's number one sensitivity in the 43~GHz band, and also Kashima 34~m was the world's third-largest one, the Kashima-Nobeyama baseline provided the highest sensitivity at 43~GHz VLBI (Figure 1). The construction of the Kashima 34~m antenna began in 1988, also almost at the same time, a domestic project of mm-VLBI (KNIFE, Kashima Nobeyama INterFrermeter) started. Nobeyama Radio Observatory provided the first cooled-HEMT 43~GHz receiver in the world to the Kashima 34~m. In October 1989, the first fringe at 43~GHz was detected. We here review the achievements of the KNIFE at that time.