J/MNRAS/345/747 RR Lyrae in 4 Fornax globular clusters (Mackey+, 2003)
RR Lyrae stars in four globular clusters in the Fornax dwarf galaxy.
Mackey A.D., Gilmore G.F.
<Mon. Not. R. Astron. Soc., 345, 747-761 (2003)>
=2003MNRAS.345..747M 2003MNRAS.345..747M
ADC_Keywords: Clusters, globular ; Stars, variable ; Photometry
Keywords: stars: horizontal branch - stars: variables: other -
globular clusters: general - galaxies: star clusters -
galaxies: individual: Fornax dwarf spheroidal
Abstract:
We have surveyed four of the globular clusters in the Fornax dwarf
galaxy (clusters 1, 2, 3 and 5) for RR Lyrae stars, using archival
F555W and F814W Hubble Space Telescope observations. We identify 197
new RR Lyrae stars in these four clusters, and 13 additional candidate
horizontal-branch variable stars. Although somewhat restricted by our
short observational baseline, we derive periods and light curves for
all of the stars in the sample, and calculate photometric parameters
such as mean magnitudes and colours. This is the first time that RR
Lyrae stars in the Fornax globular clusters have been quantitatively
identified and measured.
Objects:
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RA (2000) DE Designation(s)
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02 39 59.3 -34 26 57 Fornax dwarf Galaxy = ESO 356- 4
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 120 197 Measured and calculated properties of the
RR Lyrae stars.
table3.dat 69 13 Photometric measurements for the candidate
RR Lyrae stars
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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- 5 A5 --- [MG2003] Name (FNVNN)
7 I1 --- Chip Chip number (0=PC, 1-3=WFC2-4)
9- 14 F6.2 pix Xpix X position relative to the reference image (1)
16- 21 F6.2 pix Ypix Y position relative to the reference image (1)
23- 27 F5.2 arcsec Rad Radius used to adjust the local background
29- 32 F4.2 --- alphac Detection completeness fraction
34- 38 F5.3 d Per Period
39 A1 --- n_Per [*] *: lower-limit measurement of the period
41- 45 A5 --- Type RR Lyrae type
47 I1 --- Nt Label of the best-fitting template (2)
49- 53 F5.3 mag rms rms noise
55- 60 F6.3 mag Mean V magnitude
62- 67 F6.3 mag Mean I magnitude
69- 73 F5.3 mag <V-I> Mean V-I colour index (3)
75- 76 I2 --- No Number of pairs of observation
78- 83 F6.3 mag Vmax Maximum V magnitude
85- 90 F6.3 mag Vmin Minimum V magnitude
92- 96 F5.3 mag DeltaV Amplitude of the V variability
98-106 F9.4 d EpochMax MJD Epoch of maximum (JD-2400000.5)
108-112 F5.3 mag (V-I)m ? Mean V-I colour at the minimum light
114-118 F5.3 mag e_(V-I)m ? rms uncertainty on (V-I)m
120 I1 --- o_(V-I)m ? Number of observation at minimum light
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Note (1): Reference images (Program ID 5917):
Fornax 1 (F1): u30m010et
Fornax 2 (F2): u30m020et
Fornax 3 (F3): u30m030et
Fornax 4 (F4): u30m040et
Note (2): Label of the best-fitting template:
1-6: RRab template
7-8: RRc template
Note (3): <V-I> is in preference to the two possible intensity
mean colours - and <V-I>
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- [MG2003] Name (FnCNN)
7 I1 --- Chip Chip number
9- 14 F6.2 pix Xpix X position relative to the reference image
16- 21 F6.2 pix Ypix Y position relative to the reference image
23- 27 F5.2 arcsec Rad Radius
29- 32 F4.2 --- alphac Completeness fraction (1)
34- 39 F6.3 mag Mean V magnitude
41- 46 F6.3 mag Mean I magnitude
48- 49 I2 --- No Number of pairs of observation
51- 56 F6.3 mag Vmax Maximum V magnitude
58- 63 F6.3 mag Vmin Minimum V magnitude
65- 69 F5.3 mag DeltaV Amplitude of the V variability
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Note (1): We also passed the artificial star measurements through the
quality filter. This allowed us to assign a detection completeness
parameter, alphac, to each real star, by finding the fraction of
successful artificial star measurements in a brightness-colour-
position bin about the real star. Values ≲ 0.25 should be
regarded with caution.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 05-Dec-2003