LICKNPM (G0): Lick Northern Proper Motion Survey Reference Galaxies
FILES:
File Dec (2000) Range #Galaxies
licknpm1.g0 +30 < Dec < +90 17,464
licknpm2.g0 0 < Dec < +30 18,268
licknpm3.g0 -24 < Dec < 0 14,785
CONTENTS: Lick Northern Proper Motion Survey Reference Galaxies (1993)
DATASET: These files come in HyperSky dataset G-14, version 19940223 Availability on HyperSky CD-ROM: Vol. 2 (1995)
DESCRIPTION: These datafiles contain a total of 50517 faint compact galaxies which define the reference frame for part 1 of the Lick Northern Proper Motion (NPM1) Survey: positions and proper motions of some 149,000 stars. This part of the survey, for which the galaxies define the reference frame, covers the sky north of Declination -23, excluding the Milky Way. The NPM survey is based on photographs taken with the Lick 51-cm (20-in) Carnegie double astrograph between 1947 and 1988, with measurements and reductions completed extending from 1975 to 1992. The rms position errors for the NPM1 reference galaxies average about 0.2 arcsec. The rms errors for the B magnitudes average about 0.25 mag.
The NPM1 reference galaxies were selected at the Lick Gaertner survey machine for the fundamental purpose of providing the absolute zero point of proper motion in each NPM1 field (Klemola, Jones, and Hanson 1987). The galaxies selected for measurement lie in the magnitude range 14 < B < 18, with most in the fainter half of this range, i.e., 16 < B < 18. Ideally, a reference galaxy should show little or no structure and have a small, generally round shape with a well-exposed core. In practice, to obtain an adequate number of galaxies, most NPM fields rely on a wider range of galaxy types, including many weak, patch-like objects. Typically, from 50 up to a limit of 100 galaxies were selected in each 6x6 deg NPM1 field. Thus, the distribution on the sky of the NPM1 reference galaxies is as nearly uniform as possible.
DATA: The HyperSky datafiles contain the following data from the catalog:
POSITION: The galaxy position for equinox 2000, precessed from the B1950 position provided in the catalog.
MAG: the blue galaxy magnitude.
IDENTIFICATION: The galaxy name as provided by the catalog. Each name contains the NPM1 declination zone and the galaxy's running number within its zone (e.g., +89.0001). The formal Lick identification of any galaxy list can be obtained by prefixing "NPM1G" to the "name" (e.g., NPM1G+89.0001).
COMMENTS: Comments will appear only for galaxies containing a position or magnitude error flag in the catalog. If an error comment appears, the number of observations for that galaxy will also appear. Possible comments are:
RA diff > 1", Dec diff > 1", RA + Dec diffs > 1", Bad position,
B mag diff > 1 mag, Bad photometry
REFERENCES
Klemola, A. R., Jones, B. F., and Hanson, R. B. 1987, AJ 94, 501
Klemola, A. R., Hanson, R. B., and Jones, B. F. 1993, AJ (in preparation)