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 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:
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RA (2000) DE Designation(s)
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17 41 53 -53 44 30 NGC 6397
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 58 19228 FORS1 V, I photometry for NGC 6397
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Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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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
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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.
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Acknowledgements: Gloria Andreuzzi, andreuzzi(at)tng.iac.es
(End) Patricia Vannier [CDS] 12-Nov-2004