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The Navy's Extragalactic Source Monitoring Program

Introduction

The US Naval Research Laboratory and the US Naval Observatory used the NRAO Green Bank Interferomter for a monitoring program of compact extragalactic radio sources during 1979--1994.4. During the period 1978--1987 active galactic nuclei were monitored as a part of the Earth Rotation Parameters Program operation of the instrument (Fiedler et al. 1987b; Waltman et al. 1991). During the period 1988--1994.4, AGNs were monitored for the purpose of detecting extreme scattering events (Fiedler et al. 1987a). Since 1994 the instrument has concentrated on Galactic X-ray binaries and extragalactic sources of high-energy radiation. Figure 1 shows the sky distribution of the sources monitored.

Figure 1---The sky distribution of sources monitored by the GBI on an Aitoff projection of the sky. Triangles indicate the position of sources whose monitoring started prior to 1988 (typically between 1979 and 1983), and circles indicate the position of sources whose monitoring started approximately in 1988. The Galactic center is at the center of the plot, and Galactic longitude increases to the left.

This site provides access to the light curves and structure functions of sources monitored during that interval. For each source we provide both plots of each quantity as well as the actual data. The observing and calibration procedures were described by Fiedler et al. (1987b) and Waltman et al. (1991). Variability analyses of these sources have been conducted by Fiedler et al. (1987b) and Lazio et al. (2001).

Data Products

Below is a table of the sources monitored with links to the actual data as well as plots of the time series.

Also available is Table 1 of Lazio et al. (2001). The source names are derived from their B1950 coordinates; a list of alternate names is available. A Fortran 77 subroutine for reading in the data is also available.

Credit

Any use of these data should include the following acknowledgment:

The Green Bank Interferometer (GBI) is a facility of the National Science Founation, operated by the National Radio Astronomy Observatory while under contract to the US Naval Observatory and Naval Research Laboratory.

Acknowledgements

We acknowledge the outstanding contribution of the staff of the Green Bank Interferometer in maintaining an aging, yet sensitive instrument. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. Radio astronomy at the Naval Research Laboratory is supported by the Office of Naval Research.

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The appearance of external hyperlinks in this document does not constitute endorsement by the U.S. Department of Defense, the U.S. Department of the Navy and the U.S. Naval Research Laboratory of the linked Web sites or of the information, products, or services contained therein. For other than authorized activities such as military exchanges and Morale, Welfare, and Recreation (MWR) sites, the U.S. Department of Defense, the Department of the Navy, and the U.S. Naval Research Laboratory do not exercise any editorial control over the information you may find at these locations.

T. Joseph W. Lazio
Last modified: Mon Apr 14 09:33:14 2003