J/ApJ/812/149 HSTPROMO. III. Dynamical distances (Watkins+, 2015)
Hubble Space Telescope Proper Motion (HSTPROMO) catalogs of Galactic globular
clusters.
III. Dynamical distances and mass-to-light ratios.
Watkins L.L., van der Marel R.P., Bellini A., Anderson J.
<Astrophys. J., 812, 149 (2015)>
=2015ApJ...812..149W 2015ApJ...812..149W (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Velocity dispersion ; Stars, distances ;
Stars, masses
Keywords: globular clusters: general; globular clusters: individual;
proper motions; stars: distances; stars: kinematics and dynamics;
stars: luminosity function, mass function
Abstract:
We present dynamical distance estimates for 15 Galactic globular
clusters (GCs) and use these to check the consistency of dynamical and
photometric distance estimates. For most of the clusters, this is the
first dynamical distance estimate ever determined. We extract
proper-motion (PM) dispersion profiles using cleaned samples of bright
stars from the Hubble Space Telescope PM catalogs recently presented
in Bellini et al. (Paper I, 2014, J/ApJ/797/115) and compile a set of
line of sight (LOS) velocity-dispersion profiles from a variety of
literature sources. Distances are then estimated by fitting spherical,
non-rotating, isotropic, constant mass-to-light ratio (M/L) dynamical
models to the PM and LOS dispersion profiles together. We compare our
dynamical distance estimates with literature photometric estimates
from the Harris GC catalog (VII/202) and find that the mean fractional
difference between the two types is consistent with zero at just
-1.9±1.7%. This indicates that there are no significant biases in
either estimation method and provides an important validation of the
stellar-evolution theory that underlies photometric distance
estimates. The analysis also estimates dynamical M/Ls for our
clusters; on average, the dynamically inferred M/Ls agree with
existing stellar-population-based M/Ls that assume a Chabrier initial
mass function (IMF) to within -8.8±6.4%, implying that such an IMF
is consistent with our data. Our results are also consistent with a
Kroupa IMF, but strongly rule out a Salpeter IMF. We detect no
correlation between our M/L offsets from literature values and our
distance offsets from literature values, strongly indicating that our
methods are reliable and our results are robust.
Description:
For our analysis, we use the HST proper-motion (PM) catalogs described
in Bellini et al. (Paper I, 2014, J/ApJ/797/115); based on archival
HST images spanning 2002 to 2013. We augment these catalogs with line
of sight (LOS) velocity data available in the literature.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 109 15 Results: distance and mass-to-light ratio estimates
table4.dat 87 555 Compilation of literature dispersion profiles
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See also:
VII/202 : Globular Clusters in the Milky Way (Harris, 1997)
J/ApJ/803/29 : HSTPROMO catalogs. II. Kinematic profiles (Watkins+, 2015)
J/AJ/149/53 : RVs of 12 Milky Way globular clusters (Kimmig+, 2015)
J/ApJ/798/23 : Radial velocities of giant stars in NGC 6388 (Lapenna+, 2015)
J/A+A/573/A115 : Radial velocities in seven globular clusters (Lardo+, 2015)
J/ApJ/797/115 : HSTPROMO I. Observations and NGC7078 results (Bellini+, 2014)
J/A+A/566/A58 : Radial velocities in M3, M13, and M92 (Kamann+, 2014)
J/ApJ/769/107 : RVs and [Fe/H] of star members of NGC 6388 (Lanzoni+, 2013)
J/A+A/552/A49 : ARGUS images of 6 Galactic GCs (Lutzgendorf+, 2013)
J/AcA/62/357 : Proper motions in 6 globular clusters (Zloczewski+, 2012)
J/ApJ/754/91 : Abundances and velocities of NGC 6397 stars (Lovisi+, 2012)
J/A+A/542/A129 : NGC 2808 central kinematics (Luetzgendorf+, 2012)
J/A+A/533/A69 : Spectroscopy of 124 RGB stars in NGC 1851 (Carretta+, 2011)
J/A+A/533/A36 : VI photometry & velocity map of NGC 6388 (Luetzgendorf+, 2011)
J/MNRAS/414/888 : ATLAS3D project. III. (Emsellem+, 2011)
J/A+A/525/A148 : Radial velocities in two globular clusters (Scarpa+, 2011)
J/A+A/520/A95 : Abundances of red giants in M54 and Sgr dSph (Carretta+, 2010)
J/ApJ/710/1032 : Proper motions in ω Cen (Anderson+, 2010)
J/MNRAS/398/1757 : RR Lyraes in SDSS stripe 82 (Watkins+, 2009)
J/MNRAS/396/2183 : RVs of red giants in ω Cen (Sollima+ 2009)
J/AJ/137/4282 : Red giant stars in clusters. II. M13 and M92 (Meszaros+, 2009)
J/AJ/133/1041 : Velocities & CMT2 photometry in globular M92 (Drukier+, 2007)
J/A+A/464/927 : Abundances of red giants in NGC 6752 (Carretta+, 2007)
J/ApJS/166/249 : Stellar dynamics & proper motions in 47Tuc (McLaughlin+, 2006)
J/ApJS/161/304 : Star clusters in Milky Way and satellites (McLaughlin+, 2005)
J/ApJ/602/264 : Proper motions and radial velocities in M15 (McNamara+, 2004)
J/ApJ/595/187 : Proper motions in M15 (McNamara+, 2003)
J/AJ/115/708 : Radial Velocities in the Field of M15 (Drukier+ 1998)
J/AJ/110/1699 : F-P observations of globular clusters (Gebhardt+ 1995)
J/AJ/109/218 : Catalogue of globular cluster profiles (Trager+ 1995)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- --- [NGC]
4- 7 I4 --- NGC Globular Cluster Name
9- 13 A5 --- OName Other names
15- 19 I5 --- Ndist [517/16519] Number of PM stars used
for the distance estimation
21- 24 F4.2 (kpc.Msun/Lsun)0.5 fpar [2.3/6.7] f parameter used in fitting
procedure (f=(Dγ)0.5; eq. 6)
26- 29 F4.2 (kpc.Msun/Lsun)0.5 e_fpar Lower 1σ uncertainty in fpar
31- 34 F4.2 (kpc.Msun/Lsun)0.5 E_fpar [0.05/0.4] Upper 1σ uncertainty
in fpar
36- 40 F5.3 (Msun/Lsun/kpc)0.5 gpar [0.2/1] g parameter used in fitting
procedure (g=(γ/D)0.5; eq. 8)
42- 46 F5.3 (Msun/Lsun/kpc)0.5 e_gpar Lower 1σ uncertainty in gpar
48- 52 F5.3 (Msun/Lsun/kpc)0.5 E_gpar Upper 1σ uncertainty in gpar
54- 58 F5.2 kpc Dist [2.3/22.6] Heliocentric distance
estimate
60- 63 F4.2 kpc e_Dist [0.08/0.9] Lower 1σ uncertainty
in Dist
65- 68 F4.2 kpc E_Dist Upper 1σ uncertainty in Dist
70- 73 F4.2 Msun/Lsun M/L [1.4/2.7] V-band mass-to-light ratio
estimate
75- 78 F4.2 Msun/Lsun e_M/L Lower 1σ uncertainty in M/L
80- 83 F4.2 Msun/Lsun E_M/L Upper 1σ uncertainty in M/L
85- 89 F5.2 10+5Msun Mcl [0.7/34.6] Total cluster mass
estimate
91- 94 F4.2 10+5Msun e_Mcl Lower 1σ uncertainty in Mclus
96- 99 F4.2 10+5Msun E_Mcl Upper 1σ uncertainty in Mclus
101-104 F4.1 kpc Distl [2.3/26.5] Literature heliocentric
distance (1)
106-109 F4.2 Msun/Lsun M/L-l [1.8/3] Literature V-band
mass-to-light ratio (2)
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Note (1): From Harris (1996, 2010 edition, see VII/202)
See also: http://physwww.physics.mcmaster.ca/~harris/mwgc.dat
Note (2): From McLaughlin & van der Marel (2005, J/ApJS/161/304).
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- --- [NGC]
4- 7 I4 --- NGC Globular Cluster Name
9- 16 F8.3 arcsec Rad [0.4/2904] Radius
18- 24 F7.3 arcsec e_Rad [0/164.2] Uncertainty in Rad
26- 31 F6.3 km/s sigma [0.2/25.7] Velocity dispersion (1)
33- 37 F5.3 km/s E_sigma [0.1/4.6] Upper uncertainty in sigma (1)
39- 43 F5.3 km/s e_sigma [0.06/3.8] Lower uncertainty in sigma (1)
45- 47 A3 --- Type Velocity dispersion data type (2)
49- 67 A19 --- Ref Text of bibliographic data source reference
69- 87 A19 --- BibCode Bibcode of data source reference
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Note (1): Proper motion (PM) measurements have been converted from mas/yr to
km/s using the distances given in Harris (1996, 2010 edition, VII/202;
http://physwww.physics.mcmaster.ca/~harris/mwgc.dat).
These distances are also listed in Table 2. Equation (2) may be used to
convert back from units of km/s to mas/yr.
Note (2): Velocity dispersion data type as follows:
LOS = Line of Sight dispersion profiles or catalog;
PM = Proper Motion dispersion profile
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History:
From electronic version of the journal
References:
Bellini et al. Paper I. 2014ApJ...797..115B 2014ApJ...797..115B Cat. J/ApJ/797/115
Watkins et al. Paper II. 2015ApJ...803...29W 2015ApJ...803...29W Cat. J/ApJS/803/29
Baldwin et al. Paper IV. 2016ApJ...827...12B 2016ApJ...827...12B Cat. J/ApJ/827/12
Bellini et al. Paper V. 2017ApJ...844..167B 2017ApJ...844..167B
Libralato et al. Paper VI. 2018ApJ...861...99L 2018ApJ...861...99L Cat. J/ApJ/861/99
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 09-Feb-2016