J/AJ/110/652 VI photometry in NGC 6352 (Fullton+ 1995)
A VIc color-magnitude diagram of the globular cluster NGC 6352 from Hubble
Space Telescope Planetary Camera observations
Fullton L.K., Carney B.W., Olszewski E.W., Zinn R., Demarque P.,
Janes K.A., Da Costa G.S., Seitzer P.
<Astron. J. 110, 652 (1995)>
=1995AJ....110..652F 1995AJ....110..652F
ADC_Keywords: Clusters, globular ; Photometry
Abstract:
The globular cluster NGC 6352, which on the basis of its Galactic
position, radial velocity, and [Fe/H] is a member of the (thick) disk
system of globular clusters, has been observed to below the
main-sequence turnoff (MSTO) using the Hubble Space Telescope. These
observations, which were obtained before the repair mission, were
analyzed using the flux-conserving iterative/recursive deconvolution
algorithm developed at the University of North Carolina. This
algorithm can produce more precise photometry than standard
PSF-fitting methods with the aberrated images. The V, (V-Ic)
color-magnitude diagram constructed from these observations places the
cluster turnoff at V=18.80±0.10. Observations with the CTIO 0.9m
telescope have been used to photometer the brighter stars in the
cluster, providing a calibration of the HST data and an estimate of
the cluster's reddening, E(B-V)=0.21±0.03. From spectroscopic
observations of the strengths of the Ca II triplet lines in red giants
in the cluster and from previous measurements in the literature, we
find that NGC 6352 is only slightly more metal rich
(Delta[Fe/H]=0.08±0.05) than the prototypical disk globular cluster,
47 Tuc. From the difference in V magnitude between the horizontal
branch and the MSTO, we find that NGC 6352 is essentially the same age
as 47 Tuc (formally, older by 0.7±2.2Gyr). Comparisons with the
latest Yale isochrones support this result and yield 14.5±2Gyr
for the age of 47 Tuc from the photometry of Hesser et al.
(1987PASP...99..739H 1987PASP...99..739H), which is consistent with other determinations.
The old age obtained for NGC 6352 provides additional evidence that
the disk system of globular clusters is very old and is in fact older
or comparable in age to several globular clusters populating the
Galactic halo.
Description:
Tables CD-1, CD-2, and CD-3 contain the photometric data used to
generate the color-magnitude diagrams in the printed paper. The tables
themselves were not printed in the paper, but were provided by the
authors for publication on the AAS CD-ROM Series.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablecd1.dat 58 2649 Ground-based data
tablecd2.dat 50 2074 HST cluster data
tablecd3.dat 50 245 HST comparison field data
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Byte-by-byte Description of file: tablecd1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- ID Star identification
6- 10 I5 --- SN []? Cross-id from Sarajedini & Norris
(1994ApJS...93..161S 1994ApJS...93..161S)
12- 18 F7.3 pix Xpos X coordinate
20- 26 F7.3 pix Ypos Y coordinate
28- 34 F7.3 mag Vmag V magnitude
36- 42 F7.3 mag e_Vmag Sigma of Vmag measurement
44- 50 F7.3 mag V-Ic V-Ic color
52- 58 F7.3 mag e_V-Ic Sigma of V-Ic measurement
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Byte-by-byte Description of file: tablecd2.dat tablecd3.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Chip Chip number
4- 7 I4 --- ID Star identification number
8 A1 --- n_ID [*] Indicates no other star on the frame
within 15 pixels
10- 15 F6.2 pix Xpos X coordinate
17- 22 F6.2 pix Ypos Y coordinate
24- 29 F6.3 mag Vmag V magnitude
31- 36 F6.3 mag e_Vmag Sigma of Vmag measurement
38- 43 F6.3 mag V-Ic V-Ic color
45- 50 F6.3 mag e_V-Ic Sigma of V-Ic measurement
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References:
Sarajedini & Norris 1994 ApJS, 93, 16 =1994ApJS...93..161S 1994ApJS...93..161S
Origin: AAS CD-ROM series, Volume 5, 1995 Lee Brotzman [ADS] 27-Sep-1995
(End) [CDS] 10-Jan-1996