J/AJ/133/2764 M31 globular clusters structural parameters (Barmby+, 2007) ================================================================================ Structural parameters for globular clusters in M 31 and generalizations for the fundamental plane. Barmby P., McLaughlin D.E., Harris W.E., Harris G.L.H., Forbes D.A. =2007AJ....133.2764B ================================================================================ ADC_Keywords: Galaxies, nearby ; Clusters, globular ; Morphology ; Photometry Keywords: galaxies: individual (M31) - galaxies: star clusters - globular clusters: general Abstract: The structures of globular clusters (GCs) reflect their dynamical states and past histories. High-resolution imaging allows the exploration of morphologies of clusters in other galaxies. Surface brightness profiles from new Hubble Space Telescope observations of 34 GCs in M31 are presented, together with fits of several different structural models to each cluster. M31 clusters appear to be adequately fit by standard King models and do not obviously require alternate descriptions with relatively stronger halos, such as are needed to fit many GCs in other nearby galaxies. The derived structural parameters are combined with corrected versions of those measured in an earlier survey in order to construct a comprehensive catalog of structural and dynamical parameters for M31 GCs with a sample size similar to that for the Milky Way. Clusters in M31, the Milky Way, Magellanic Clouds, the Fornax dwarf spheroidal, and NGC 5128 define a very tight fundamental plane with identical slopes. The combined evidence for these widely different galaxies strongly reinforces the view that old GCs have near-universal structural properties, regardless of host environment. Description: We have used material from several different HST programs. Program GO-10260 (PI: W. Harris) obtained ACS Wide Field Channel (WFC) images centered on 6 clusters in M31 and 12 clusters in NGC 5128, selected to have M_V_<-10.5 and (for M31) no previous HST observations. Program GO-9719 (PI: T. Bridges) obtained ACS High Resolution Channel (HRC) images of three M31 clusters, using exposure times of 2020 s in F606W and 2680s in F814W in 2003 August and September. Program GO-8664 (PI: W. Harris) targeted 24 M31 clusters with a range of properties for imaging with STIS in snapshot mode; exposure times were 480s in the unfiltered 50CCD/CL imaging mode. These data were obtained in fall 2000 and winter 2001. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table1.dat 101 94 Integrated measurements for M31 clusters table2.dat 47 3349 F606W, F814W, or V intensity profiles for 33 GCs table4.dat 147 209 Basic parameters of fits to 49 profiles of 33 GCs table5.dat 166 161 Derived structural and photometric parameters table6.dat 184 160 Derived dynamical parameters of GCs in M31 table7.dat 79 161 Galactocentric radii and {kappa}-space parameters table8.dat 152 161 Predicted aperture velocity dispersions -------------------------------------------------------------------------------- See also: J/AJ/119/727 : M31 globular clusters photometry (Barmby+, 2000) J/AJ/123/2490 : RV and [Fe/H] of M31 globular cluster system (Perrett+, 2002) Byte-by-byte Description of file: table1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 48 A48 --- Prog Program 50- 54 A5 --- Name M31 cluster name 55 A1 --- f_Name [*] cluster near edge (1) 57- 60 F4.2 --- eps Average ellipticity 62- 64 I3 deg PA ? Position angle (2) 66- 70 F5.2 mag Vmag The F606W band magnitude (3) 72- 76 F5.2 mag Imag ? The F814W band magnitude 78- 81 F4.2 mag E(B-V) The (B-V) color excess 83- 87 F5.2 kpc RGC Galactocentric distance 89- 93 F5.2 [-] [Fe/H] Metallicity 95- 97 F3.1 [-] e_[Fe/H] Error in [Fe/H] 99-101 A3 --- r_[Fe/H] Reference for [Fe/H] (4) -------------------------------------------------------------------------------- Note (1): the asterisk (*) indicates a cluster close to the image edge; its measurements do not cover the full range of radial distance. Note (2): Measured East of North. Note (3): F606W for ACS-observed clusters, except G001 (F555W). Note (4): References as follows: HBK = Huchra et al., 1991ApJ...370..495H, HBK NNN-NNN P02 = Perrett et al., 2002, Cat. B00 = Barmby et al., 2000, Cat. , [BHB2000] NNN-NNN AVE = no measurement: [Fe/H]=-1.2pm0.6 assigned -------------------------------------------------------------------------------- Byte-by-byte Description of file: table2.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 5 A5 --- Name M31 cluster name 7- 10 A4 --- Det Detector (HRC, STIS, WFC) 12- 15 A4 --- Filt Filter (F555, F606, F814 or V) 17- 23 F7.4 arcsec Rad Radius 25- 34 F10.3 solLum/pc2 Int Intensity 36- 43 F8.3 solLum/pc2 e_Int Uncertainty in Int 45- 47 A3 --- Flag Profile flag (1) -------------------------------------------------------------------------------- Note (1): Profile flag as follows: BAD = the intensity value is deemed dubious because it strongly deviates from its neighbors or is obviously affected by nearby bright stars or image artifacts. SAT = the isophotal intensity is above the imposed saturation limit of 70cts/s/pix. DEP = the radius is inside R<2pix=0.1" and the isophotal intensity is dependent on its neighbors. The ELLIPSE output includes brightnesses for 15 radii inside 2 pixels, but these are all measured from the same 13 central pixels and are clearly not statistically independent. To avoid excessive weighting of the central regions of the cluster in the fits, only intensities at radii R_min_, R_min_+(0.5, 1.0, 2.0px), R>2.5px, were used. OK = none of the above apply and the point is used in model fitting -------------------------------------------------------------------------------- Byte-by-byte Description of file: table4.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 5 A5 --- Name M31 cluster name 7- 14 A8 --- De/Fi Detector/Filter combination 16- 20 F5.3 mag AV Extinction in the F606W band 22- 27 F6.3 mag Vcol Color term (1) 29- 33 F5.3 mag e_Vcol Error in Vcol 35- 36 I2 --- Npts Number of ok points in intensity profile 38- 40 A3 --- Mod Model used (G1) 42- 48 F7.2 --- Chi2 Model {chi}^2^_min_ (2) 50- 56 F7.2 solLum/pc2 Ibkg Best-fit background intensity 58- 62 F5.2 solLum/pc2 e_Ibkg Error in Ibkg 64- 68 F5.2 --- W0 Central dimensionless potential of best fit 70- 73 F4.2 --- E_W0 Upper limit error in W0 75- 78 F4.2 --- e_W0 Lower limit error in W0 80- 83 F4.2 --- c/n Concentration or Sersic index of best fit 85- 88 F4.2 --- E_c/n Upper limit error in c/n 90- 93 F4.2 --- e_c/n Lower limit error in c/n 95- 99 F5.2 mag/arcsec2 mu0 Surface brightness (3) 101-104 F4.2 mag/arcsec2 E_mu0 Upper limit error in mu0 106-109 F4.2 mag/arcsec2 e_mu0 Lower limit error in mu0 111-116 F6.3 [arcsec] logra Log of the angular scale radius 118-122 F5.3 [arcsec] E_logra Upper limit error in logra 124-128 F5.3 [arcsec] e_logra Lower limit error in logra 130-135 F6.3 [pc] logrp Log of the physical scale radius (4) 137-141 F5.3 [pc] E_logrp Upper limit error in logrp 143-147 F5.3 [pc] e_logrp Lower limit error in logrp -------------------------------------------------------------------------------- Note (1): To transform photometry from the native bandpass of the data to the standard V scale. Note (2): Obtained for that class of model (without the re-scaling applied for uncertainty estimation). Note (3): Calibrated and extinction-corrected in the native bandpass of the data. Note (4): Obtained from the angular scale assuming D=780kpc for M31. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table5.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 5 A5 --- Name M31 cluster name 7- 14 A8 --- De/Fi Detector/Filter combination 16- 18 A3 --- Mod Model used (G1) 20- 24 F5.2 [pc] logRt Log of model tidal radius (1) 26- 29 F4.2 [pc] E_logRt Upper limit error in logRt 31- 34 F4.2 [pc] e_logRt Lower limit error in logRt 36- 41 F6.3 [pc] logRc Log of model projected core radius 43- 47 F5.3 [pc] E_logRc Upper limit error in logRc 49- 53 F5.3 [pc] e_logRc Lower limit error in logRc 55- 60 F6.3 [pc] logRh Log of model projected half-light or effective radius 62- 66 F5.3 [pc] E_logRh Upper limit error in logRh 68- 72 F5.3 [pc] e_logRh Lower limit error in logRh 74- 78 F5.3 [-] logh/c Log the projected half-light radius to core radius (2) 80- 84 F5.3 [-] E_logh/c Upper limit error in logh/c 86- 90 F5.3 [-] e_logh/c Lower limit error in logh/c 92- 95 F4.2 [solLum/pc2] logI0 Log of best-fit central V band luminosity surface density 97-100 F4.2 [solLum/pc2] E_logI0 Upper limit error in logI0 102-105 F4.2 [solLum/pc2] e_logI0 Lower limit error in logI0 107-110 F4.2 [solLum/pc3] logj0 Log of central V band luminosity volume density (3) 112-115 F4.2 [solLum/pc3] E_logj0 Upper limit error in logj0 117-120 F4.2 [solLum/pc3] e_logj0 Lower limit error in logj0 122-125 F4.2 [solLum] logL Log of total integrated V band model luminosity 127-130 F4.2 [solLum] E_logL Upper limit error in logL 132-135 F4.2 [solLum] e_logL Lower limit error in logL 137-141 F5.2 mag Vmag Total extinction-corrected apparent V band magnitude of a model cluster 143-146 F4.2 mag E_Vmag Upper limit error in Vmag 148-151 F4.2 mag e_Vmag Lower limit error in Vmag 153-156 F4.2 [solLum/pc2] logIh Log of V band luminosity surface density (4) 158-161 F4.2 [solLum/pc2] E_logIh Upper limit error in logIh 163-166 F4.2 [solLum/pc2] e_logIh Lower limit error in logIh -------------------------------------------------------------------------------- Note (1): Always infinite for Sersic models. Note (2): A measure of cluster concentration. Note (3): For Sersic models the density at the 3-D radius r_0_. Note (4): Averaged over the half-light/effective radius. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table6.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 5 A5 --- Name M31 cluster name 7- 14 A8 --- De/Fi Detector/Filter combination 16- 20 F5.3 Sun M/L Mass-to-light ratio (1) 22- 26 F5.3 Sun E_M/L Upper limit error in M/L 28- 32 F5.3 Sun e_M/L Lower limit error in M/L 34- 36 A3 --- Mod Model used (G1) 38- 41 F4.2 [solMass] logM Log of integrated model mass 43- 46 F4.2 [solMass] E_logM Upper limit error in logM 48- 51 F4.2 [solMass] e_logM Lower limit error in logM 53- 57 F5.2 [10-7J] logE Log of integrated binding energy in units of erg 59- 62 F4.2 [10-7J] E_logE Upper limit error in logE 64- 67 F4.2 [10-7J] e_logE Lower limit error in logE 69- 72 F4.2 [solMass/pc2] logS0 Log of central surface mass density 74- 77 F4.2 [solMass/pc2] E_logS0 Upper limit error in logS0 79- 82 F4.2 [solMass/pc2] e_logS0 Lower limit error in logS0 84- 88 F5.2 [solMass/pc3] logrho Log of central volume density (2) 90- 93 F4.2 [solMass/pc3] E_logrho Upper limit error in logrho 95- 98 F4.2 [solMass/pc3] e_logrho Lower limit error in logrho 100-103 F4.2 [solMass/pc2] logSh Log of surface mass density averaged over the effective radius R_h_ 105-108 F4.2 [solMass/pc2] E_logSh Upper limit error in logSh 110-113 F4.2 [solMass/pc2] e_logSh Lower limit error in logSh 115-119 F5.3 [km/s] logsig Log of predicted line-of-sight velocity dispersion (3) 121-125 F5.3 [km/s] E_logsig Upper limit error in logsig 127-131 F5.3 [km/s] e_logsig Lower limit error in logsig 133-137 F5.3 [km/s] logvel Log of predicted central escape velocity 139-143 F5.3 [km/s] E_logvel Upper limit error in logvel 145-149 F5.3 [km/s] e_logvel Lower limit error in logvel 151-155 F5.2 [yr] logtau Log of two-body relaxation time (4) 157-160 F4.2 [yr] E_logtau Upper limit error in logtau 162-165 F4.2 [yr] e_logtau Lower limit error in logtau 167-172 F6.3 [solMass.s3/km3/pc3] logf0 Log of measure of the model's central phase-space density or relaxation time (5) 174-178 F5.3 [solMass.s3/km3/pc3] E_logf0 Upper limit error in logf0 180-184 F5.3 [solMass.s3/km3/pc3] e_logf0 Lower limit error in logf0 -------------------------------------------------------------------------------- Note (1): Adopted for each object from the analysis in Section 4. The values assume an age of 13Gyr for all clusters. The error bars include a +/-2Gyr uncertainty in age, as well as the previously tabulated uncertainties in [Fe/H]. Note (2): For Sersic models the density at the 3-D radius r_0_. Note (3): At the cluster center (or at R_c_ for Sersic models). Note (4): At the model projected half-mass radius. Note (5): At r_0_ for Sersic models. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table7.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 5 A5 --- Name M31 cluster name 7- 14 A8 --- De/Fi Detector/Filter combination 16- 20 F5.2 kpc RGC Galactocentric distance 22- 24 A3 --- Mod Model used (G1) 26- 31 F6.3 --- kappam1 The {kappa}_m,1_ parameter (1) 33- 37 F5.3 --- E_kappam1 Upper limit error in kappam1 39- 43 F5.3 --- e_kappam1 Lower limit error in kappam1 45- 49 F5.3 --- kappam2 The {kappa}_m,2_ parameter (1) 51- 55 F5.3 --- E_kappam2 Upper limit error in kappam2 57- 61 F5.3 --- e_kappam2 Lower limit error in kappam2 63- 67 F5.3 --- kappam3 The {kappa}_m,3_ parameter (1) 69- 73 F5.3 --- E_kappam3 Upper limit error in kappam3 75- 79 F5.3 --- e_kappam3 Lower limit error in kappam3 -------------------------------------------------------------------------------- Note (1): Modified versions of the {kappa} parameters of Bender et al. (1992ApJ...399..462B), who found that early-type galaxies and (separately) globular clusters defined the edges of planes in {kappa} space. We define the parameters using mass rather than luminosity surface density, as this is more useful for comparing globulars to younger clusters and galaxies (see McLaughlin et al., 2008MNRAS.384..563M), and emphasize this by using the notation {kappa}_m,i_. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table8.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 5 A5 --- Name M31 cluster name 7- 14 A8 --- De/Fi Detector/Filter combination 16- 20 F5.3 solMass/solLum M/L The mass-to-light ratio 22- 26 F5.3 solMass/solLum E_M/L Upper limit error in M/L 28- 32 F5.3 solMass/solLum e_M/L Lower limit error in M/L 34- 36 A3 --- Mod Model used (G1) 38- 43 F6.3 [pc] logRhp Log of the physical scale radius (1) 45- 50 F6.3 [arcsec] logRha Log of the angular scale radius 52- 56 F5.3 [arcsec] E_logRha Upper limit error in logRha 58- 62 F5.3 [arcsec] e_logRha Lower limit error in logRha 64- 68 F5.3 [km/s] logsR/8 Log of predicted velocity dispersion within R_h_/8 70- 74 F5.3 [km/s] E_logsR/8 Upper limit error in logsR/8 76- 80 F5.3 [km/s] e_logsR/8 Lower limit error in logsR/8 82- 86 F5.3 [km/s] logsR/4 Log of predicted velocity dispersion within R_h_/4 88- 92 F5.3 [km/s] E_logsR/4 Upper limit error in logsR/4 94- 98 F5.3 [km/s] e_logsR/4 Lower limit error in logsR/4 100-104 F5.3 [km/s] logsR Log of predicted velocity dispersion within R_h_ 106-110 F5.3 [km/s] E_logsR Upper limit error in logsR 112-116 F5.3 [km/s] e_logsR Lower limit error in logsR 118-122 F5.3 [km/s] logs4R Log of predicted velocity dispersion within 4R_h_ 124-128 F5.3 [km/s] E_logs4R Upper limit error in logs4R 130-134 F5.3 [km/s] e_logs4R Lower limit error in logs4R 136-140 F5.3 [km/s] logs8R Log of predicted velocity dispersion within 8R_h_ 142-146 F5.3 [km/s] E_logs8R Upper limit error in logs8R 148-152 F5.3 [km/s] e_logs8R Lower limit error in logs8R -------------------------------------------------------------------------------- Note (1): Obtained from the angular scale assuming D=780kpc for M31. -------------------------------------------------------------------------------- Global Notes: Note (G1): the models are: K66 = King 1966AJ.....71...64K W = Wilson 1975AJ.....80..175W S = Sersic 1968 (model in R^1/n^) History: From electronic version of the journal ================================================================================ (End) Greg Schwarz [AAS], Patricia Vannier [CDS] 27-May-2009