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Formalism and quality of a proper motion link with extragalactic objects for astrometric satellite missions
The accuracy of the link of the proper motion system of astrometricsatellite missions like AMEX and GAIA is discussed. Monte-Carlo methodswere used to simulate catalogues of positions and proper motions ofquasars and galaxies to test the link. The main conclusion is, thatfuture satellite missions like GAIA may be ``self-calibrated'' by theirmeasurements of QSOs, while additional measurements from radio stars orHST-data are needed to calibrate the less deep reaching astrometricsatellite missions of AMEX type.
| The Arizona-New Mexico Spectroscopic Survey of Galaxies. I. Data for the Western End of the Perseus Supercluster
We present new optical spectroscopic data for 347 galaxies in the regionof the Perseus supercluster. The new data were obtained using theSteward Observatory 2.3 m telescope and cover the whole optical window.Included are redshifts (for 345 objects), absorption-line equivalentwidths, a continuum index measuring the 4000 Å break, andemission-line flux ratios. After 11 objects are rejected for being toofaint and redshifts for 26 objects are added from the literature, wearrive at a complete sample of 361 galaxies. The distribution ofredshifts for the whole sample is examined, and we show the relationshipof the continuum index to morphology.
| Arcsecond Positions of UGC Galaxies
We present accurate B1950 and J2000 positions for all confirmed galaxiesin the Uppsala General Catalog (UGC). The positions were measuredvisually from Digitized Sky Survey images with rms uncertaintiesσ<=[(1.2")2+(θ/100)2]1/2,where θ is the major-axis diameter. We compared each galaxymeasured with the original UGC description to ensure high reliability.The full position list is available in the electronic version only.
| A 21 CM survey of the Pisces-Perseus supercluster. I - The declination zone +27.5 to +33.5 degrees
Neutral-hydrogen 21 cm line data for a sample of galaxies in the regionbounded by 22 h less than R.A. less than 04h, + 27 deg 30 arcmin Dec.less than + 33 deg 30 arcmin are presented as the first installment of asurvey of galaxies in the region of the Pisces-Perseus supercluster. Ofthe 415 galaxies observed in this strip with the Arecibo 305 mtelescope, 342 have been detached in the 21 cm line; another ten haveuseful upper limits to their H I content. The sample includes mostspiral, irregular, and dwarf galaxies larger than 1 arcmin; in selectedareas, spirals to a limiting magnitude of + 15.7 have been observed. Thevelocity distribution of the 511 galaxies with known redshift in thiszone deviates markedly from that expected for a similar sample ofrandomly placed objects. The region contains significant clustering inall three dimensions.
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