Ground-based CCD astrometry with wide-field imagers - II. A star catalog for m 67: WFI@2.2 m MPG/ESO astrometry, FLAMES @ VLT radial velocities
Articolo
Data di Pubblicazione:
2008
Abstract:
Context: The solar-age open cluster M 67 (C0847+120, NGC 2682) is a touchstone in studies of the old Galactic disk. Despite its outstanding role, the census of cluster membership for M 67 at fainter magnitudes and their properties are not well-established.
Aims: Using proprietary and archival ESO data, we have obtained astrometric, photometric, and radial velocities of stars in a 34×33 arcmin2 field centered on the old open cluster M 67.
Methods: The two-epoch archival observations separated by 4 years and acquired with the Wide-Field Imager at the 2.2 m MPG/ESO telescope were reduced with our new astrometric techniques, as described in the first paper in this series. The same observations served to derive calibrated BVI photometry in M 67. Radial velocities were measured using the archival and new spectroscopic data obtained at the VLT.
Results: We have determined relative proper motions and membership probabilities for ~2400 stars. The precision of proper motions for optimally exposed stars is 1.9 mas yr-1, gradually degrading down to ~5 mas yr-1 at V=20. Our relatively precise proper motions at V>16 were first obtained in this magnitude range for M 67. Radial velocities were measured for 211 stars in the same field. We also present a detailed comparison with recent theoretical isochrones from several independent groups.
Conclusions: For the M 67 area, we provide positions, calibrated BVI photometry, relative proper motions, membership probabilities, and radial velocities. We demonstrate that ground-based CCD mosaic observations just a few years apart are producing proper motions, allowing reliable membership determination. We have produced a catalog that is electronically available to the astronomical community.
Based on observations with the MPG/ESO 2.2 m and ESO/VLT telescopes, located at La Silla and Paranal Observatory, Chile, under DDT program 278.D-5027, and the archive material. This is paper 33 of the WIYN Open Cluster Study (WOCS). Full Table [see full text] is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/484/609
Aims: Using proprietary and archival ESO data, we have obtained astrometric, photometric, and radial velocities of stars in a 34×33 arcmin2 field centered on the old open cluster M 67.
Methods: The two-epoch archival observations separated by 4 years and acquired with the Wide-Field Imager at the 2.2 m MPG/ESO telescope were reduced with our new astrometric techniques, as described in the first paper in this series. The same observations served to derive calibrated BVI photometry in M 67. Radial velocities were measured using the archival and new spectroscopic data obtained at the VLT.
Results: We have determined relative proper motions and membership probabilities for ~2400 stars. The precision of proper motions for optimally exposed stars is 1.9 mas yr-1, gradually degrading down to ~5 mas yr-1 at V=20. Our relatively precise proper motions at V>16 were first obtained in this magnitude range for M 67. Radial velocities were measured for 211 stars in the same field. We also present a detailed comparison with recent theoretical isochrones from several independent groups.
Conclusions: For the M 67 area, we provide positions, calibrated BVI photometry, relative proper motions, membership probabilities, and radial velocities. We demonstrate that ground-based CCD mosaic observations just a few years apart are producing proper motions, allowing reliable membership determination. We have produced a catalog that is electronically available to the astronomical community.
Based on observations with the MPG/ESO 2.2 m and ESO/VLT telescopes, located at La Silla and Paranal Observatory, Chile, under DDT program 278.D-5027, and the archive material. This is paper 33 of the WIYN Open Cluster Study (WOCS). Full Table [see full text] is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/484/609
Tipologia CRIS:
01.01 - Articolo in rivista
Elenco autori:
Yadav, Rks; Bedin, Luigi; Piotto, Giampaolo; Anderson, J; Cassisi, S; Villanova, Sandro; Platais, I; Pasquini, L; AL MOMANY, Yazan; Sagar, R.
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