J/AJ/146/20 Structural parameters for 79 globular clusters in M31 (Wang+, 2013)
Structural parameters for globular clusters in M31.
Wang S., Ma J.
<Astron. J., 146, 20 (2013)>
=2013AJ....146...20W 2013AJ....146...20W
ADC_Keywords: Galaxies, nearby ; Clusters, globular ; Morphology ; Photometry
Keywords: galaxies: individual: M31 - galaxies: star clusters: general -
galaxies: stellar content
Abstract:
In this paper, we present surface brightness profiles for 79 globular
clusters in M31, using images observed with the Hubble Space
Telescope, some of which are from new observations. The structural and
dynamical parameters are derived from fitting the profiles to several
different models for the first time. The results show that in the
majority of cases, King models fit the M31 clusters just as well as
Wilson models and better than Sérsic models. However, there are 11
clusters best fitted by Sersic models with the Sersic index n>2,
meaning that they have cuspy central density profiles. These clusters
may be the well-known core-collapsed candidates. There is a bimodality
in the size distribution of M31 clusters at large radii, which is
different from their Galactic counterparts. In general, the properties
of clusters in M31 and the Milky Way fall in the same regions of
parameter spaces. The tight correlations of cluster properties
indicate a "fundamental plane" for clusters, which reflects some
universal physical conditions and processes operating at the epoch of
cluster formation.
Description:
Our 79 clusters were selected from Barmby et al. (2002AJ....123.1937B 2002AJ....123.1937B)
and Mackey et al. (2007ApJ...655L..85M 2007ApJ...655L..85M). We used images observed with
the Hubble Space Telescope, some of which are new observations. We
obtained the combined drizzled images from the Hubble Legacy Archive.
The images in the bandpass close to V-band (F555W or F606W) and I-band
(F814W) were preferred; in all other cases, the images from F300W,
F435W, or F475W were selected. The images with high resolution were
preferentially adopted (WFPC2/PC or ACS/WFC), followed by those
obtained with WFPC2/WFC.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 89 79 Integrated measurements for 79 sample clusters in M31
table3.dat 54 9857 The intensity profiles for 79 sample clusters in M31
table5.dat 134 456 Basic parameters of 79 sample clusters in M31
table6.dat 205 456 Derived structural and photometric parameters of 79
sample clusters in M31
table7.dat 213 456 Derived dynamical parameters of 79 sample clusters
in M31
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See also:
J/ApJS/199/37 : GALEX catalog of star clusters in M31 (Kang+, 2012)
J/AJ/141/61 : Star clusters in M31. II. (Caldwell+, 2011)
J/AJ/137/94 : Star clusters in M31 (Caldwell+, 2009)
J/MNRAS/396/1075 : GCs in nearby dwarf galaxies. II (Georgiev+, 2009)
J/AJ/138/1667 : HST survey of young clusters in M31. III. (Barmby+, 2009)
J/AJ/133/2764 : M31 globular clusters structural parameters (Barmby+, 2007)
J/AJ/132/447 : Surface Brightness of 38 Gal. Globular Clusters (Noyola+, 2006)
J/A+A/416/917 : Revised Bologna Catalog of M31 GCs (Galleti+, 2004)
J/AJ/119/727 : M31 globular clusters photometry (Barmby+, 2000)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Name Name of the cluster in M31
8- 11 F4.2 --- bEll [0/1]? Ellipticity in bluer filters
13- 16 F4.2 --- e_bEll ? Uncertainty in bEll
18- 21 I4 deg bPA [-183/90]? Position angle in bluer filters
23- 24 I2 deg e_bPA ? Uncertainty in bPA
26- 29 F4.2 --- rEll [0/1]? Ellipticity in redder filters
31- 34 F4.2 --- e_rEll ? Uncertainty in rEll
36- 39 I4 deg rPA [-170/64]? Position angle in redder filters
41- 42 I2 deg e_rPA ? Uncertainty in rPA
44- 49 F6.3 mag Bmag ? The B-band Vega magnitude
51- 55 F5.2 mag Vmag The V-band Vega magnitude
57- 61 F5.2 mag Imag The I-band Vega magnitude
63- 67 F5.2 kpc Rgc Distance from galactic center
69- 72 F4.2 mag E(B-V) Reddening
74- 78 F5.2 [Sun] [Fe/H] Metallicity
80- 83 F4.2 [Sun] e_[Fe/H] ? Uncertainty in [Fe/H]
85- 89 F5.2 Gyr Age Age
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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- 6 A6 --- Name Name of the cluster in M31
8- 16 A9 --- Det Detector used (G1)
18 A1 --- --- [F]
19- 21 I3 nm Flt Filter used (wavelength) (G2)
22 A1 --- --- [W]
24- 30 F7.4 arcsec Rad [0/35] Radius
32- 41 F10.3 Lsun/pc2 Int Intensity
43- 50 F8.3 Lsun/pc2 e_Int Uncertainty in Int
52- 54 A3 --- f_Int Profile flag (BAD, DEP, OK) (1)
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Note (1): Profile flag are:
OK = Used to constrain the model fit;
DEP = May lead to excessive weighting of the central regions of clusters
(see Barmby et al., 2007, cat. J/AJ/133/2764; Mclaughlin et al.,
2008MNRAS.384..563M 2008MNRAS.384..563M, for details);
BAD = Individual isophote that deviated strongly from its neighbor or shows
irregular features. Was deleted by hand.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Name Name of the cluster in M31
8- 16 A9 --- Det Detector used (G1)
18- 20 I3 nm Flt Filter used (wavelength) (G2)
22- 23 I2 --- Np Number of points (1)
25- 27 A3 --- Mod Model code (K66, W, S) (G3)
29- 34 F6.2 --- chi2 Minimum χ2 obtained in the fits
36- 42 F7.2 Lsun/pc2 Ibkg Best-fitted background intensity
44- 49 F6.2 Lsun/pc2 e_Ibkg Uncertainty in Ibkg
51- 55 F5.2 --- W0 ? Best-fitting central potential (2)
57- 60 F4.2 --- E_W0 ? Upper limit uncertainty in W0
62- 65 F4.2 --- e_W0 ? Lower limit uncertainty in W0
67- 70 F4.2 --- c/n Concentration; log(rt/r0)
72- 75 F4.2 --- E_c/n Upper limit uncertainty in c/n
77- 80 F4.2 --- e_c/n Lower limit uncertainty in c/n
82- 86 F5.2 mag/arcsec2 mu0 Best-fit central surface brightness
88- 91 F4.2 mag/arcsec2 E_mu0 Upper limit uncertainty in mu0
93- 96 F4.2 mag/arcsec2 e_mu0 Lower limit uncertainty in mu0
98-103 F6.3 [arcsec] logRa Best model-fit angular log scale radius
105-109 F5.3 [arcsec] E_logRa Upper limit uncertainty in logRa
111-115 F5.3 [arcsec] e_logRa Lower limit uncertainty in logRa
117-122 F6.3 [pc] logRp Best model-fit physical log scale radius
124-128 F5.3 [pc] E_logRp Upper limit uncertainty in logRp
130-134 F5.3 [pc] e_logRp Lower limit uncertainty in logRp
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Note (1): In the intensity profile that were used for constraining
the model fits.
Note (2): W0=-Φ(0)/σ20.
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Name Name of the cluster in M31
8- 16 A9 --- Det Detector used (G1)
18- 20 I3 nm Flt Filter used (wavelength) (G2)
22- 24 A3 --- Mod Model code (K66, W, S) (G3)
26- 29 F4.2 [pc] logRt ? Log of model tidal radius logRtid (3)
31- 34 F4.2 [pc] E_logRt ? Upper limit uncertainty in logRt
36- 39 F4.2 [pc] e_logRt ? Lower limit uncertainty in logRt
41- 46 F6.3 [pc] logRc Log projected core radius logRc (4)
48- 53 F6.3 [pc] E_logRc Upper limit uncertainty in logRc
55- 59 F5.3 [pc] e_logRc Lower limit uncertainty in logRc
61- 66 F6.3 [pc] logRh Log of projected half-light radius
logRh (5)
68- 72 F5.3 [pc] E_logRh Upper limit uncertainty in logRh
74- 78 F5.3 [pc] e_logRh Lower limit uncertainty in logRh
80- 85 F6.3 [-] logh/c Log of half-light radius to core radius
log(Rh/Rc) ratio (6)
87- 91 F5.3 [-] E_logh/c Upper limit uncertainty in logh/c
93- 97 F5.3 [-] e_logh/c Lower limit uncertainty in logh/c
99-103 F5.2 [Lsun/pc2] logI0 ?=99.9 Log of best-fit central V-band
luminosity surface density logI0 (7)
105-109 F5.2 [Lsun/pc2] E_logI0 ?=99.9 Upper limit uncertainty in logI0
111-115 F5.2 [Lsun/pc2] e_logI0 ?=99.9 Lower limit uncertainty in logI0
117-121 F5.2 [Lsun/pc3] logj0 ?=99.9 Log of central luminosity volume
density (in the V-band) log(j0)
123-127 F5.2 [Lsun/pc3] E_logj0 ?=99.9 Upper limit uncertainty in logj0
129-133 F5.2 [Lsun/pc3] e_logj0 ?=99.9 Lower limit uncertainty in logj0
135-139 F5.2 [Lsun] logL ?=99.9 Log of V-band total integrated
model luminosity logLV
141-145 F5.2 [Lsun] E_logL ?=99.9 Upper limit uncertainty in logL
147-151 F5.2 [Lsun] e_logL ?=99.9 Lower limit uncertainty in logL
153-157 F5.2 mag Vmag ?=99.9 Total V-band magnitude Vtot (8)
159-163 F5.2 mag E_Vmag ?=99.9 Upper limit uncertainty in Vmag
165-169 F5.2 mag e_Vmag ?=99.9 Lower limit uncertainty in Vmag
171-175 F5.2 [Lsun/pc2] logIh ?=99.9 Log of V-band luminosity surface
density logIh (9)
177-181 F5.2 [Lsun/pc2] E_logIh ?=99.9 Upper limit uncertainty in logIh
183-187 F5.2 [Lsun/pc2] e_logIh ?=99.9 Lower limit uncertainty in logIh
189-193 F5.2 mag/arcsec2 muV ?=99.9 V-band surface brightness
<µV>h (10)
195-199 F5.2 mag/arcsec2 E_muV ?=99.9 Upper limit uncertainty in muV
201-205 F5.2 mag/arcsec2 e_muV ?=99.9 Lower limit uncertainty in muV
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Note (3): Infinity for Sersic model.
Note (4): Of the model fitting a cluster, defined as I(Rc)=I0/2.
Note (5): Or effective radius of a model, containing half the totat luminosity
in projection.
Note (6): A measure of cluster concentration and relatively more
model-independent than W0 or c.
Note (7): In the V-band, defined as logI0=0.4(26.358-µV,0),
where 26.358 is the "Coefficient" corresponding to a solar absolute
magnitude MV,Sun=+4.786 (C. Willmer, private communication).
Note (8): Of a model cluster. Defined as:
Vmag=4.786-2.5log(LV/LSun)+5log(D/10pc).
Note (9): Averaged over the half-light/effective radius in the V-band, defined
as logIh=log(LV/2πR2h).
Note (10): In magnitude over the half-light/effective radius in the V-band,
defined as <µV>h=26.358-2.5logIh.
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Name Name of the cluster in M31
8- 16 A9 --- Det Detector used (G1)
18- 20 I3 nm Flt Filter used (wavelength) (G2)
22- 26 F5.3 Msun/Lsun M/L V-band mass-to-light ratio ΥV
28- 32 F5.3 Msun/Lsun E_M/L Upper limit uncertainty in M/L
34- 38 F5.3 Msun/Lsun e_M/L Lower limit uncertainty in M/L
40- 42 A3 --- Mod Model code (G3)
44- 48 F5.2 [Msun] logM ?=99.9 Log integrated cluster mass (11)
50- 54 F5.2 [Msun] E_logM ?=99.9 Upper limit uncertainty in logM
56- 60 F5.2 [Msun] e_logM ?=99.9 Lower limit uncertainty in logM
62- 66 F5.2 [10-7J] logE ?=99.9 Log integrated binding energy
logEb (in erg) (12)
68- 72 F5.2 [10-7J] E_logE ?=99.9 Upper limit uncertainty in logE
74- 78 F5.2 [10-7J] e_logE ?=99.9 Lower limit uncertainty in logE
80- 84 F5.2 [Msun/pc2] logS0 ?=99.9 Log central surface mass density
logΣ0 (13)
86- 90 F5.2 [Msun/pc2] E_logS0 ?=99.9 Upper limit error in logS0
92- 96 F5.2 [Msun/pc2] e_logS0 ?=99.9 Lower limit error in logS0
98-102 F5.2 [Msun/pc3] logr0 ?=99.9 Log central volume density
logρ0 (14)
104-108 F5.2 [Msun/pc3] E_logr0 ?=99.9 Upper limit uncertainty in logr0
110-114 F5.2 [Msun/pc3] e_logr0 ?=99.9 Lower limit uncertainty in logr0
116-120 F5.2 [Msun/pc2] logSh ?=99.9 Log surface mass density
logΣh (15)
122-126 F5.2 [Msun/pc2] E_logSh ?=99.9 Upper limit error in logSh
128-132 F5.2 [Msun/pc2] e_logSh ?=99.9 Lower limit error in logSh
134-139 F6.3 [km/s] logs ?=99.9 Log predicted line-of-sight
velocity dispersion logσ0 (16)
141-146 F6.3 [km/s] E_logs ?=99.9 Upper limit uncertainty in logs
148-153 F6.3 [km/s] e_logs ?=99.9 Lower limit uncertainty in logs
155-160 F6.3 [km/s] logv ?=99.90 Log predicted central escape
velocity logVesc (17)
162-167 F6.3 [km/s] E_logv ?=99.9 Upper limit uncertainty in logv
169-174 F6.3 [km/s] e_logv ?=99.9 Lower limit uncertainty in logv
176-180 F5.2 [yr] logt ?=99.9 Log two-body relaxation time
(logτ) (18)
182-186 F5.2 [yr] E_logt ?=99.9 Upper limit uncertainty in logt
188-192 F5.2 [yr] e_logt ?=99.9 Lower limit uncertainty in logt
194-199 F6.3 [Msun/(pc.km/s)3] logf0 ?=99.9 Log central phase-space
density logf0 (19)
201-206 F6.3 [Msun/(pc.km/s)3] E_logf0 ?=99.9 Upper limit error in logf0
208-213 F6.3 [Msun/(pc.km/s)3] e_logf0 ?=99.9 Lower limit error in logf0
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Note (11): Estimated as logMt=log{Ypsilon}+logLV.
Note (12): Defined as Eb=-(1/2)∫rt0(4πr2ρΦdr).
Note (13): Estimated as logΣ0=log{Ypsilon}+logI0.
Note (14): Estimated as logρ=log{Ypsilon}+logj0.
Note (15): Averaged over the half-light/effective radius, Rh, estimated as
logΣh=log{Ypsilon}+logIh.
Note (16): At the cluster center.
Note (17): With which a star can move out from the center fo a cluster, defined
as v2esc,0/σ20=2[W0+GMtot/rtσ20].
Note (18): At the model-projected half-mass radius, estimated as:
tr,h=[(2.06e6yr)/ln(0.4Mtot/m*)][(Mtot1/2Rh3/2^)/m*]; where
m* is the average stellar mass in a cluster, assumed to be 0.5MSun.
Note (19): Defined as f0=ρ0/(2πσ20)3/2.
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Global notes:
Note (G1): Detectors are aCS/WFC, WFPC2/PC, or WFPC2/WFC.
Note (G2): F300W, F435W, F450W, F475W, F555W, F606W, or F814W.
Note (G3): Model code defined as follows:
K66 = King model (1966AJ.....71...64K 1966AJ.....71...64K)
W = Wilson model (1975AJ.....80..175W 1975AJ.....80..175W)
S = Sersic model (1968; see Elson, Fall & Freeman 1987ApJ...323...54E 1987ApJ...323...54E)
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 19-Jun-2014