J/AJ/122/3219 M3 and M13 CCD BV photometry (Rey+, 2001)
CCD photometry of the classic second-parameter globular clusters M3 and M13.
Rey S.-C., Yoon S.-J., Lee Y.-W., Chaboyer B., Sarajedini A.
<Astron. J. 122, 3219 (2001)>
=2001AJ....122.3219R 2001AJ....122.3219R
ADC_Keywords: Clusters, globular ; Photometry, CCD ; Photometry, UBV
Keywords: color-magnitude diagrams - globular clusters: individual (M3, M13) -
stars: evolution - stars: horizontal-branch
Abstract:
We present high-precision V, B-V color-magnitude diagrams (CMDs) for
the classic second-parameter globular clusters M3 and M13 from
wide-field, deep CCD photometry. The data for the two clusters were
obtained during the same photometric nights with the same instrument,
allowing us to determine accurate relative ages. Based on a
differential comparison of the CMDs using the Δ(B-V) method, an
age difference of 1.7±0.7Gyr is obtained between these two clusters.
We compare this result with our updated horizontal-branch (HB)
population models, which confirm that the observed age difference can
produce the difference in HB morphology between the clusters. This
provides further evidence that age is the dominant second parameter
that influences HB morphology.
Objects:
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RA (2000) DE Designation(s)
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13 42 11.2 +28 22 32 M 3 = NGC 5272
16 41 41.4 +36 27 37 M 13 = NGC 6205
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 47 2356 CCD Photometry for M3
table2.dat 47 2152 CCD Photometry for M13
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See also:
J/A+A/290/69 : M3 photographic photometry (Buonanno+, 1994)
J/A+A/320/757 : M3 stars CCD photometry (Ferraro+ 1997)
J/AJ/108/1786 : Blue stragglers + variable stars in M3 (Guhathakurta+, 1994)
J/PAZh/20/693 : Identification and coordinates in NGC 5272 (Evstigneeva+ 1994)
J/AJ/120/1364 : Abundances in M3 and M13 (Cavallo+, 2000)
J/A+AS/102/397 : Colour magnitude diagram of M13 (Guarnieri+ 1993)
J/AJ/113/669 : Stars in M13 core (Cohen+ 1997)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- RYL M3 identification number (Cl* NGC 5272 RYL NNNN)
6- 12 F7.2 pix Xpix The X pixel coordinate (G1)
14- 20 F7.2 pix Ypix The Y pixel coordinate (G1)
22- 27 F6.3 mag Vmag The V band magnitude
29- 33 F5.3 mag e_Vmag The uncertainty in Vmag
35- 40 F6.3 mag B-V The (B-V) color index
42- 46 F5.3 mag e_B-V The uncertainty in B-V
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- RYL M13 identification number (Cl* NGC 6205 RYL NNNN)
6- 12 F7.2 pix Xpix The X pixel coordinate (G1)
14- 20 F7.2 pix Ypix The Y pixel coordinate (G1)
22- 27 F6.3 mag Vmag The V band magnitude
29- 33 F5.3 mag e_Vmag The uncertainty in Vmag
35- 40 F6.3 mag B-V The (B-V) color index
42- 46 F5.3 mag e_B-V The uncertainty in B-V
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Global notes:
Note (G1): The field of view of the CCD is roughly 9.5' with a pixel
scale of 0.28". North is to the left, and east is down. We observed
two partially overlapping fields in M3 and M13, respectively. One
field was about 12' southwest of the cluster center in order to
produce a deep and well-defined MS in each cluster. Six long
(200-800s) and six short (20-60s) exposures were obtained at this
location. In order to ensure a large sample of SGB and RGB stars, a
second field off the cluster center by 9' west was observed with three
medium (80-240s) and three short (20-60s) exposures.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 07-Mar-2002