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J/A+A/425/509       VI photometry of  NGC 6397               (Andreuzzi+, 2004)

VLT FORS-1 observations of NGC 6397: Evidence for mass segregation. Andreuzzi G., Testa V., Marconi G., Alcaino G., Alvarado F., Buonanno R. <Astron. Astrophys., 425, 509-518 (2004)> =2004A&A...425..509A (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Photometry Keywords: Galaxy: globular clusters: individual: NGC 6397 - stars: low-mass - stars: luminosity function, mass function Description: We used VLT-FORS1 data to obtain photometry for stars located within 10 arcmin from the center of the cluster NGC 6397. The data taken in service mode in 1999 (field2, RA=17 41 03.5, DE=-53 45 36) and in 2000 (field1, RA=17 41 14.3, DE=-53 44 27.6) were retrieved electronically from the ESO-STECF archive (proposals: 63.H-0721(A) and 65.H-0531(B)). The resulting V, V-I photometry reachs a limiting magnitude of V∼27. As our fields were affected by a large number of saturated stars and, as the photometric procedures can include those peaks in the final photometric catalogue, we decided to eliminate from the catalogue the spurious identifications before performing the data analysis. In this way, a total of 15081 and 11161 objects were detected, respectively, in the fields f1 and f2. We used the 7059 objects in common between these two fields to optimize our photometry by computing a weighted average between the values of the magnitudes of a given star in each catalogue and to transform the frame coordinates to a common coordinate system referred to the field f2. At the end of this procedure an homogeneous set of instrumental magnitudes, color and position were obtained for a total of 19228 objects. Objects: ----------------------------------------- RA (2000) DE Designation(s) ----------------------------------------- 17 41 53 -53 44 30 NGC 6397 ----------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file catalog.dat 58 19228 FORS1 V, I photometry for NGC 6397
Byte-by-byte Description of file: catalog.dat
Bytes Format Units Label Explanations
1- 8 F8.3 pix xpos x coordinate (1) 10- 17 F8.3 pix ypos y coordinate (1) 21- 26 F6.3 mag Vmag Johnson V magnitude 28- 32 F5.3 mag e_Vmag Johnson V photometric error 36- 41 F6.3 mag Imag Johnson I magnitude 43- 47 F5.3 mag e_Imag Johnson I photometric error 52- 58 I7 --- Seq Identification number
Note (1): North is up and East is left. 1 pix = 0.2" The position of the center is x=6.71', y=8.5', as indicated in Fig. 1.
Acknowledgements: Gloria Andreuzzi, andreuzzi(at)tng.iac.es
(End) Patricia Vannier [CDS] 12-Nov-2004
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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