J/MNRAS/456/3757 Open-cluster density profiles (Seleznev, 2016)
Open-cluster density profiles derived using a kernel estimator.
Seleznev A.F.
<Mon. Not. R. Astron. Soc., 456, 3757-3773 (2016)>
=2016MNRAS.456.3757S 2016MNRAS.456.3757S (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Models ; Morphology
Keywords: open clusters and associations: general
Abstract:
Surface and spatial radial density profiles in open clusters are
derived using a kernel estimator method. Formulae are obtained for the
contribution of every star into the spatial density profile. The
evaluation of spatial density profiles is tested against open-cluster
models from N-body experiments with N=500. Surface density profiles
are derived for seven open clusters (NGC 1502, 1960, 2287, 2516, 2682,
6819 and 6939) using Two-Micron All-Sky Survey data and for different
limiting magnitudes. The selection of an optimal kernel half-width is
discussed. It is shown that open-cluster radius estimates hardly
depend on the kernel half-width. Hints of stellar mass segregation and
structural features indicating cluster non-stationarity in the regular
force field are found. A comparison with other investigations shows
that the data on open-cluster sizes are often underestimated. The
existence of an extended corona around the open cluster NGC 6939 was
confirmed. A combined function composed of the King density profile
for the cluster core and the uniform sphere for the cluster corona is
shown to be a better approximation of the surface radial density
profile.The King function alone does not reproduce surface density
profiles of sample clusters properly. The number of stars, the cluster
masses and the tidal radii in the Galactic gravitational field for the
sample clusters are estimated. It is shown that NGC 6819 and 6939 are
extended beyond their tidal surfaces.
Description:
The purpose of the present study was to show the efficiency of the
kernel estimation of the surface and spatial density profiles of open
star clusters and their N-body models, especially in the outer cluster
region, and to demonstrate the necessity of taking into account the
corona component of the open cluster when choosing the model for the
approximation of the surface density profile .
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 82 7 Sample clusters
table9.dat 83 7 Stellar masses at the boundaries of magnitude
intervals in the sample clusters
table2.dat 231 551 Data on surface density radial profiles for NGC 1502
table3.dat 231 301 Data on surface density radial profiles for NGC 1960
table4.dat 231 301 Data on surface density radial profiles for NGC 2287
table5.dat 231 551 Data on surface density radial profiles for NGC 2516
table6.dat 231 576 Data on surface density radial profiles for NGC 2682
table7.dat 231 276 Data on surface density radial profiles for NGC 6819
table8.dat 231 801 Data on surface density radial profiles for NGC 6939
table11.dat 208 42 Approximation of the surface density profiles
of the sample clusters
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Cluster Cluster name
10- 12 A3 --- OName Other name
14- 18 F5.1 deg GLON Galactic longitude
20- 24 F5.1 deg GLAT Galactic latitude
26- 29 F4.2 mag E(B-V) Redenning
31- 34 F4.2 mag e_E(B-V) rms uncertainty on E(B-V)
36- 40 F5.2 mag MOD Distance modulus
42- 45 F4.2 mag e_MOD rms uncertainty on MOD
47- 50 I4 pc Dist Distance
52- 54 I3 pc e_Dist rms uncertainty on Dist
56- 59 F4.2 [yr] logAge Age
61- 64 F4.2 [yr] e_logAge rms uncertainty on logAge
66- 67 I2 arcmin h kernel half-width
69- 71 I3 arcmin Rf Radius of the field considered
73- 82 A10 --- FileName Name of the table with data on surface density
radial profiles
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Byte-by-byte Description of file: table9.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Cluster Cluster name
10- 12 A3 --- OName Other name
14- 18 F5.2 mag Jup Magnitude of the upper end of the cluster
sequence in the CMD
20- 23 F4.2 mag e_Jup rms uncertainty on Jmagup
25- 28 F4.2 Msun M11 Stellar mass at the boundaries of magnitude
interval for J=11mag
30- 33 F4.2 Msun e_M11 rms uncertainty on M11
35- 38 F4.2 Msun M12 Stellar mass at the boundaries of magnitude
interval for J=12mag
40- 43 F4.2 Msun e_M12 rms uncertainty on M12
45- 48 F4.2 Msun M13 Stellar mass at the boundaries of magnitude
interval for J=13mag
50- 53 F4.2 Msun e_M13 rms uncertainty on M13
55- 58 F4.2 Msun M14 Stellar mass at the boundaries of magnitude
interval for J=14mag
60- 63 F4.2 Msun e_M14 rms uncertainty on M14
65- 68 F4.2 Msun M15 Stellar mass at the boundaries of magnitude
interval for J=15mag
70- 73 F4.2 Msun e_M15 rms uncertainty on M15
75- 78 F4.2 Msun M16 Stellar mass at the boundaries of magnitude
interval for J=16mag
80- 83 F4.2 Msun e_M16 rms uncertainty on M16
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Byte-by-byte Description of file: table[2345678].dat
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Bytes Format Units Label Explanations
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1- 7 F7.3 arcmin r Distance from the cluster centre
9- 16 F8.6 --- F11 Kernel estimate of the surface density radial
profile with the kernel half-width at Jlim=11mag
18- 25 F8.6 --- e_F11 Lower boundary of the confidence interval
at Jlim=11mag
27- 34 F8.6 --- E_F11 Upper boundary of the confidence interval
at Jlim=11mag
36- 43 F8.6 --- H11 Surface density histogram with the bin width
of 4 arcmin at Jlim=11mag
45- 52 F8.6 --- F12 Kernel estimate of the surface density radial
profile with the kernel half-width at Jlim=12mag
54- 61 F8.6 --- e_F12 Lower boundary of the confidence interval
at Jlim=12mag
63- 70 F8.6 --- E_F12 Upper boundary of the confidence interval
at Jlim=12mag
72- 79 F8.6 --- H12 Surface density histogram with the bin width
of 4 arcmin at Jlim=12mag
81- 88 F8.6 --- F13 Kernel estimate of the surface density radial
profile with the kernel half-width at Jlim=13mag
90- 97 F8.6 --- e_F13 Lower boundary of the confidence interval
at Jlim=13mag
99-106 F8.6 --- E_F13 Upper boundary of the confidence interval
at Jlim=13mag
108-115 F8.6 --- H13 Surface density histogram with the bin width
of 4 arcmin at Jlim=13mag
117-124 F8.6 --- F14 Kernel estimate of the surface density radial
profile with the kernel half-width at Jlim=14mag
126-133 F8.6 --- e_F14 Lower boundary of the confidence interval
at Jlim=14mag
135-142 F8.6 --- E_F14 Upper boundary of the confidence interval
at Jlim=14mag
144-151 F8.6 --- H14 Surface density histogram with the bin width
of 4 arcmin at Jlim=14mag
153-161 F9.6 --- F15 Kernel estimate of the surface density radial
profile with the kernel half-width at Jlim=15mag
163-171 F9.6 --- e_F15 Lower boundary of the confidence interval
at Jlim=15mag
173-181 F9.6 --- E_F15 Upper boundary of the confidence interval
at Jlim=15mag
183-191 F9.6 --- H15 Surface density histogram with the bin width
of 4 arcmin at Jlim=15mag
193-201 F9.6 --- F16 Kernel estimate of the surface density radial
profile with the kernel half-width at Jlim=16mag
203-211 F9.6 --- e_F16 Lower boundary of the confidence interval
at Jlim=16mag
213-221 F9.6 --- E_F16 Upper boundary of the confidence interval
at Jlim=16mag
223-231 F9.6 --- H16 Surface density histogram with the bin width
of 4 arcmin at Jlim=16mag
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Byte-by-byte Description of file: table11.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Cluster Cluster name
10- 11 I2 mag Jlim Limiting magnitude in J band
13- 15 I3 arcmin Rc Visual estimate of the cluster radius
17- 18 I2 arcmin e_Rc rms uncertainty on Rc
20- 24 F5.3 arcmin-2 Fbvis Visual estimate of the surface density of
the stellar background
26- 31 F6.4 arcmin-2 e_Fbvis rms uncertainty on Fbvis
the stellar background
33- 36 I4 --- N Estimate of the cluster star number
38- 40 I3 --- e_N rms uncertainty on the estimate of the
cluster star number
42- 46 F5.2 arcmin-2 kKC k parameter for approximation by the
combined model (King profile plus corona)
49- 52 F4.2 arcmin-2 e_kKC ?=- rms uncertainty on kKC
54- 58 F5.2 arcmin rcKC Scale parameter for the cluster core
radius for approximation by the combined
model (King profile plus corona)
60- 63 F4.2 arcmin e_rcKC rms uncertainty on rcKC
65- 69 F5.2 arcmin rtKC Cluster core radius for approximation by
the combined model
(King profile plus corona)
71- 75 F5.2 arcmin e_rtKC rms uncertainty on rtKC
78- 83 F6.4 arcmin-2 FbKC Surface density of the stellar background
for approximation by the combined model
(King profile plus corona)
86- 92 F7.5 arcmin-2 e_FbKC rms uncertainty on FbKC
94- 99 F6.2 arcmin R2KC Cluster corona radius for approximation
by the combined model
(King profile plus corona)
101-104 F4.2 arcmin e_R2KC rms uncertainty on R2KC
106-113 F8.6 10-3arcmin-3 DensKC Spatial density of the corona for
approximation by the combined model
(King profile plus corona)
115-122 F8.6 10-3arcmin-3 e_DensKC rms uncertainty on DensKC
124-131 E8.3 --- chi2KC Chi-square parameter for approximation by
the combined model
(King profile plus corona)
133-136 I4 --- NmodKC Cluster star number for approximation by
the combined model
(King profile plus corona)
138-141 I4 --- NcoroKC Star number of the cluster corona for
approximation by the combined model
(King profile plus corona)
143-145 I3 --- NcoreKC Star number of the cluster core for
approximation by the combined model
(King profile plus corona)
147-152 F6.3 arcmin-2 kK k parameter for approximation by the
King model (King profile)
154-158 F5.3 arcmin-2 e_kK rms uncertainty on kK
160-164 F5.2 arcmin rcK Cluster core radius for approximation by
the King model (King profile)
166-169 F4.2 arcmin e_rcK rms uncertainty on rcK
171-175 F5.1 arcmin rtK Tidal radius for approximation by the
King model (King profile)
177-180 F4.1 arcmin e_rtK rms uncertainty on rtK
182-187 F6.4 arcmin-2 FbK Surface density of the stellar background
for approximation by the King model
(King profile)
189-194 F6.4 arcmin-2 e_FbK rms uncertainty on FbK
196-203 E8.3 --- chi2K Chi-square parameter for approximation by
the King model (King profile)
205-208 I4 --- NmodK Cluster star number for approximation by
the King model (King profile)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 07-Oct-2016