J/A+A/688/A180 Radial gradient of stellar populations (Scalco+, 2024)
The HST Large Programme on omega Centauri.
VI. The radial gradient of the stellar populations.
Scalco M., Bedin L., Vesperini E.
<Astron. Astrophys. 688, A180 (2024)>
=2024A&A...688A.180S 2024A&A...688A.180S (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Photometry, HST ; Proper motions
Keywords: techniques: photometric - Hertzsprung-Russell and C-M diagrams -
globular clusters: individual: NGC 5139
Abstract:
In this paper we present the analysis of Hubble Space Telescope (HST)
observations of the globular cluster Omega Centauri. Our analysis
combines data obtained in this work with previously published HST data
from an earlier article of this series and {encompasses} a broad
portion of the cluster's radial extension. Our findings reveal a
significant radial variation in the fraction of stars within the two
largest stellar populations, showing that one of the main
second-population groups (referred to as the blue main sequence (bMS)
group) is more centrally concentrated than the first-population group
(referred to as the red main sequence (rMS) group). Additionally, we
explore the spatial variations of the other, smaller stellar
populations (referred to as MSa and MSd) and find a qualitatively
similar, but weaker, radial decrease in the fraction of stars in these
populations at larger distances from the cluster centre. Only one of
the populations identified (MSe) does not show any significant radial
variation.
Description:
Astro-photometric catalogs of 3 different fields of the globular
cluster Omega Centauri. For each field we provide photometry in
different filters, astrometric positions and membership probability.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 82 13 List of HST WFC3 observations of fields F4 and F5
tablea1.dat 201 22 Distribution of stars among various populations
in the analysed fields
astrom.dat 72 274682 Astrometric file
method1.dat 86 1421154 Method-one photometric file
method2.dat 70 1421154 Method-two photometric file
method3.dat 70 1421154 Method-three photometric file
gaia_id.dat 29 274682 Gaia identification number for sources in common
b18.dat 14 11936 Bellini et al. (2018ApJ...853...86B 2018ApJ...853...86B,
Cat. J/ApJ/853/86) identification number
for sources in common
pop_id.dat 15 317233 Population identifier
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See also:
J/ApJ/853/86 : HST large programme on ω Centauri. II. (Bellini+, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- Field Field identifier
4- 8 I5 --- PID Program ID
10- 16 A7 --- PPI Program PI
18- 26 A9 --- Inst Instrument
28- 32 A5 --- Filt Filter (F275W, F336W, F438W, F606W, F814W)
34- 65 A32 s Exp Exposures
67- 82 A16 --- Date Observation date
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 21 A21 --- Pop Population
23- 27 I5 --- NSTc Number of stars for the central field
29- 34 F6.2 % Frc ? Fraction of stars for the central field
36- 39 F4.2 % e_Frc ? Fraction of stars error for the central field
42- 46 F5.2 % Frcs ? Fraction of stars obtained solely from the
counts of classified stars,
for the central field
48- 51 F4.2 % e_Frcs ? Fraction of stars error obtained solely
from the counts of classified stars,
for the central field
54- 57 I4 --- NST5 ? Number of stars for the field F5
59- 64 F6.2 % Fr5 ? Fraction of stars for the field F5
66- 69 F4.2 % e_Fr5 ? Fraction of stars error for the field F5
72- 76 F5.2 % Fr5s ? Fraction of stars obtained solely from the
counts of classified stars, for the field F5
78- 81 F4.2 % e_Fr5s ? Fraction of stars error obtained solely
from the counts of classified stars,
for the field F5
84- 87 I4 --- NST4 ? Number of stars for the field F4
89- 94 F6.2 % Fr4 ? Fraction of stars for the field F4
96- 99 F4.2 % e_Fr4 ? Fraction of stars error for the field F4
102-106 F5.2 % Fr4s ? Fraction of stars obtained solely from the
counts of classified stars, for the field F4
108-111 F4.2 % e_Fr4s ? Fraction of stars error obtained solely
from the counts of classified stars,
for the field F4
114-117 I4 --- NST2 ? Number of stars for the field F2
119-124 F6.2 % Fr2 ? Fraction of stars for the field F2
126-129 F4.2 % e_Fr2 ? Fraction of stars error for the field F2
132-136 F5.2 % Fr2s ? Fraction of stars obtained solely from the
counts of classified stars, for the field F2
138-141 F4.2 % e_Fr2s ? Fraction of stars error obtained solely
from the counts of classified stars,
for the field F2
144-147 I4 --- NST3 ? Number of stars for the field F3
149-154 F6.2 % Fr3 ? Fraction of stars for the field F3
156-159 F4.2 % e_Fr3 ? Fraction of stars error for the field F3
162-166 F5.2 % Fr3s ? Fraction of stars obtained solely from the
counts of classified stars, for the field F3
168-171 F4.2 % e_Fr3s ? Fraction of stars error obtained solely
from the counts of classified stars,
for the field F3
175-177 I3 --- NST1 ? Number of stars for the field F1
179-184 F6.2 % Fr1 ? Fraction of stars for the field F1
186-189 F4.2 % e_Fr1 ? Fraction of stars error for the field F1
192-196 F5.2 % Fr1s ? Fraction of stars obtained solely from the
counts of classified stars, for the field F1
198-201 F4.2 % e_Fr1s ? Fraction of stars error obtained solely
from the counts of classified stars,
for the field F1
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Byte-by-byte Description of file: astrom.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- Field Field identifier
4- 9 I6 --- ID Star internal identifier
12- 20 F9.4 pix Xpos X pixel coordinate; 0.04"/pix
22- 31 F10.4 pix Ypos Y pixel coordinate; 0.04"/pix
33- 47 F15.11 deg RAdeg Right Ascension (ICRS) at Ep=2016.0
49- 63 F15.11 deg DEdeg Declination (ICRS) at Ep=2016.0
65- 72 F8.4 % Pmemb Membership probability
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Byte-by-byte Description of file: method1.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- Field Field identifier
4- 9 I6 --- ID Star internal identifier
11- 15 A5 --- Filt Filter (F110W, F160W, F275W, F336W, F438W,
F606W, F814W)
17- 21 A5 --- Exp Exposure (LONG or SHORT, only for WFC3/IR)
23- 30 F8.4 mag mag ?=-99.999 Vega magnitude in Filter (1)
32- 41 F10.4 --- rms ?=-99.999 Magnitude in Filter RMS (2)
43- 47 F5.3 --- QFIT ?=0 QFIT value (3)
49- 56 F8.2 --- O ?=0 O value (3)
58- 64 F7.4 --- RADXS ?=0 RADXS value (3)
66- 67 I2 --- Nf Number of single exposures star is found
69- 70 I2 --- Ng Number of good measurements
72- 77 F6.1 e Sky Local sky value
79- 84 F6.1 e rSky Local RMS of the sky
86 I1 --- Sat ? Saturation flag (4)
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Note (1): Flagged to -99.999 for not found stars in a give filter.
Note (2): Flagged to -99.999 for stars found <2 times in a given filter.
Note (3): Flagged to 0 for not found stars in a given filter.
Note (4): In case of only long exposures:
0 = unsaturated
1 = saturated
In case of both long and short exposures:
0 = unsaturated in the long exposures
1 = saturated in the long exposures but not in the short ones
2 = saturated both in the long and in the short exposures
Not provided for WFC3/IR filters.
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Byte-by-byte Description of file: method2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- Field Field identifier
4- 9 I6 --- ID Star internal identifier
11- 15 A5 --- Filt Filter (F110W, F160W, F275W, F336W, F438W,
F606W, F814W)
17- 21 A5 --- Exp Exposure (LONG or SHORT, only for WFC3/IR)
23- 30 F8.4 mag mag ?=-99.999 Vega magnitude in filter (1)
32- 41 F10.4 --- rms ?=-99.999 Magnitude in filter RMS (2)
43- 47 F5.3 --- QFIT ?=0 QFIT value (3)
49- 56 F8.2 --- O ?=0 O value (3)
58- 64 F7.4 --- RADXS ?=0 RADXS value (3)
66- 67 I2 --- Nf Number of single exposures star is found
69- 70 I2 --- Ng Number of good measurements
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Note (1): Flagged to -99.999 for not found stars in a give filter.
Note (2): Flagged to -99.999 for stars found <2 times in a given filter.
Note (3): Flagged to 0 for not found stars in a given filter.
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Byte-by-byte Description of file: method3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- Field Field identifier
4- 9 I6 --- ID Star internal identifier
11- 15 A5 --- Filt Filter (F110W, F160W, F275W, F336W, F438W,
F606W, F814W)
17- 21 A5 --- Exp Exposure (LONG or SHORT, only for WFC3/IR)
23- 30 F8.4 mag mag ?=-99.999 Vega magnitude in Filter (1)
32- 41 F10.4 --- rms ?=-99.999 Magnitude in Filter RMS (2)
43- 47 F5.3 --- QFIT ?=0 QFIT value (3)
49- 56 F8.2 --- O ?=0 O value (3)
58- 64 F7.4 --- RADXS ?=0 RADXS value (3)
66- 67 I2 --- Nf Number of single exposures star is found
69- 70 I2 --- Ng Number of good measurements
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Note (1): Flagged to -99.999 for not found stars in a give filter.
Note (2): Flagged to -99.999 for stars found <2 times in a given filter.
Note (3): Flagged to 0 for not found stars in a given filter.
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Byte-by-byte Description of file: gaia_id.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- Field Field identifier
4- 9 I6 --- ID Star internal identifier
11- 29 I19 --- GaiaDR3 ? Gaia DR3 internal identification number
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Byte-by-byte Description of file: b18.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- Field Field identifier
5- 9 I5 --- ID Star internal identifier
11- 14 I4 --- B18 ? Bellini et al. (2018ApJ...853...86B 2018ApJ...853...86B,
Cat. J/ApJ/853/86) internal identification
number
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Byte-by-byte Description of file: pop_id.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
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1- 2 A2 --- Field Field identifier
4- 9 I6 --- ID Star internal identifier
12 I1 --- Pop Population identifier (1)
14- 15 I2 --- sPop Sub-population identifier (2)
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Note (1): Population identifier as follows:
0 = none
1 = MSa
2 = bMS
3 = rMS
4 = MSd
5 = MSe
6 = Unidentified+Binaries
Note (2): Sub-population identifier as follows:
0 = none
1 = MSa1
2 = MSa2
3 = bMS1
4 = bMS2
5 = bMS3
6 = rMS1
7 = rMS2
8 = rMS3
9 = MSd1
10 = MSd2
11 = MSd3
12 = MSe1
13 = MSe2
14 = MSe3
15 = MSe4
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Acknowledgements:
Michele Scalco, michele.scalco(at)inaf.it
References:
Milone et al., Paper I 2017MNRAS.469..800M 2017MNRAS.469..800M
Bellini et al., Paper II 2018ApJ...853...86B 2018ApJ...853...86B, Cat. J/ApJ/853/86
Libralato et al., Paper III 2018ApJ...854...45L 2018ApJ...854...45L
Scalco et al., Paper IV 2021MNRAS.505.3549S 2021MNRAS.505.3549S
Gerasimov et al., Paper V 2022ApJ...930...24G 2022ApJ...930...24G
(End) Patricia Vannier [CDS] 14-Jun-2024