Absorption Line Survey of Distant galaxies using Nobeyama 45-m Telescope and Wideband and High-Dispersion Spectro-correlator System

2007 Fiscal Year Final Research Report Summary

• Project/Area Number: 17340057
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Astronomy
• Research Institution: National Astronomical Observatory of Japan
• Principal Investigator: OKUMURA Sachiko National Astronomical Observatory of Japan, Division of Radio Astronomy, Associate Professor (20224842)
• Co-Investigator(Kenkyū-buntansha): KUNO Nario National Astronomical Observatory of Japan, Division of Radio Astronomy, Associate Professor (30311179)
• Project Period (FY): 2005 – 2007
• Keywords: high-dispersion spectroscopy / Radio astronomy / distant galaxies / ultra wideband observations / spectro-correlator

Research Abstract

This research is aimed at making ultra wideband and high-dispersion spectro-correlator system using the FX-type spectro-correlator and the 4 Gsps high-speed analog-digital (A/D) converter previously developed. We planed to install this spectro-correlator system to Nobeyama 45-m telescope and to evaluate the system performance by the ultra wideband and high-dispersion spectroscopic observations. Finally the absorption-line survey observations of distant galaxies were planned with the high-performance ultra wideband and high-dispersion spectro-correlator system.
We have made the following examinations and experiments;
1. Wideband and high-dispersion spectro-correlator system: A test correlator for the ALMA was moved to Nobeyama Radio Observatory from Mitaka campus, and the correlator was installed to the computer room in the 45-m building. We confirmed its performance with the diagnosis tests at Mitaka and Nobeyama (2005). We also developed the ND conversion circuit and its interface circu it with the test FX correlator (2005-2006). After that, we made the performance evaluation tests with the combination of the ND conversion circuit, the test FX correlator and their interface circuit. The optimization of the parameters of the spectro-correlator system was extensively continued (2006-2007).
2. Wideband analog-signal transfer/conversion system: We discussed the appropriate wideband intermediate-frequency conversion system for this wideband and high-dispersion spectro-correlator in the 45-m observing system. We newly prepared a local signal source (9GHz) and a reference signal generator to make the wideband intermediate-frequency conversion system combined with the wideband and high-dispersion spectro-correlator (2006-2007).
3. Correlator system control software : The development of the correlator control software was started after the complement of all the hardware of the spectro-correlator system. We have just confirmed the time-synchronized start of the signal processing of the spectro-correlator in the 45-m observing system (2007).