Details

Autor(en) / Beteiligte

• Röser, S.
• Schilbach, E.
• Schwan, H.
• Kharchenko, N. V.
• Piskunov, A. E.
• Scholz, R.-D.

Titel

PPM-Extended (PPMX) – a catalogue of positions and proper motions

Ist Teil von

• Astronomy and astrophysics (Berlin), 2008-09, Vol.488 (1), p.401-408

Ort / Verlag

EDP Sciences

Erscheinungsjahr

2008

Link zum Volltext

Quelle

EZB Free E-Journals

Beschreibungen/Notizen

• Aims. We build a catalogue PPM-Extended (PPMX) on the ICRS system which is complete down to a well-defined limiting magnitude and contains the best presently available proper motions suited for kinematic studies in the Galaxy. Methods. We perform a rigorous weighted least-squares adjustment of individual observations, spread over more than a century, to determine mean positions and proper motions. The stellar content of PPMX is taken from GSC 1.2 supplemented by catalogues like ARIHIP, PPM and Tycho-2 at the bright end. All observations have been weighted according to their individual accuracy. The catalogue has been screened towards rejecting false entries in the various source catalogues. Results. PPM-Extended (PPMX) is a catalogue of 18 088 919 stars containing astrometric and photometric information. Its limiting magnitude is about 15.2 in the GSC photometric system. PPMX consists of three parts: a) a survey complete down to $R_{\rm U} = 12.8$ in the magnitude system of UCAC2; b) additional stars of high-precision proper motions, and c) all other stars from GSC 1.2 identified in 2MASS. The typical accuracy of the proper motions is 2 mas/y for 66 percent of the survey stars (a) and the high-precision stars (b), and about 10 mas/y for all other stars. PPMX contains photometric information from ASCC-2.5 and 2MASS.