Galactic Structure with the GSSS Plate Archive II:\\ Colors and Proper Motions toward the Main Meridional Section

Previous abstract Next abstract

Session 58 -- The Galaxy
Display presentation, Thursday, 2, 1994, 9:20-6:30

[58.08] Galactic Structure with the GSSS Plate Archive II:\\ Colors and Proper Motions toward the Main Meridional Section

M. G. Lattanzi, B.M.Lasker (STScI), A.Spagna (OATo), B. J. M$^c$Lean (STScI), G.Massone (OATo), B.Bucciarelli (STScI), R.Burg (JHU), M.Postman (STScI)

As part of our pilot project we present the results of a magnitude-limited survey of absolute proper motions and colors down to V=18.5 in two regions, one at the North galactic pole, and one in the plane toward the anti-center portion of the Galaxy main meridional section. We have explored 25 square degrees of field N081 at b $\approx$ 0$^\circ$. Absorption and reddening are quite strong in this direction (A$_V$ is about 4 mag/Kpc) with a patchwise pattern typical of the plane fields. Young and very young open clusters are within the region studied, and also sites which show very recent star formation. Both CM and Reduced Proper Motion (RPM) diagrams are used to analyze the survey data, i.e. to identify the various stellar populations and peculiar objects. A discussion of candidate optical counterparts of the IRAS point-like sources in the field is presented. In addition we show how this work applies to characterizing the ROSAT X-ray sky survey detections in this region.

The NGP region covers about 50 square degrees of the N321 and N322 fields. Here, we concentrate on the comparison with the surveys of S. Majewski (about 3 mag deeper but only 1 \% of the area of this study) and A. Spaenhauer (which only goes down to V$\simeq$17).

We also discuss the issues of establishing the rest frame on the plates, photometric and astrometric accuracy, and reliability of star/galaxy classification.

Thursday program listing