J/ApJ/829/108 Kinematic data of Galactic globular clusters (Eadie+, 2016)
Bayesian mass estimates of the Milky Way: the dark and light sides of
parameter assumptions.
Eadie G.M., Harris W.E.
<Astrophys. J., 829, 108-108 (2016)>
=2016ApJ...829..108E 2016ApJ...829..108E (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Milky Way ; Proper motions
Keywords: dark matter; galaxies: kinematics and dynamics; Galaxy: general;
Galaxy: halo; globular clusters: general; methods: statistical
Abstract:
We present mass and mass profile estimates for the Milky Way (MW)
Galaxy using the Bayesian analysis developed by Eadie et al.
(2015ApJ...806...54E 2015ApJ...806...54E) and using globular clusters (GCs) as tracers of
the Galactic potential. The dark matter and GCs are assumed to follow
different spatial distributions; we assume power-law model profiles
and use the model distribution functions described in Evans et al.
(1997MNRAS.286..315E 1997MNRAS.286..315E) and Deason et al. (2012MNRAS.424L..44D 2012MNRAS.424L..44D). We
explore the relationships between assumptions about model parameters
and how these assumptions affect mass profile estimates. We also
explore how using subsamples of the GC population beyond certain radii
affect mass estimates. After exploring the posterior distributions of
different parameter assumption scenarios, we conclude that a
conservative estimate of the Galaxy's mass within 125kpc is
5.22x1011M☉, with a 50% probability region of
(4.79,5.63)x1011M☉. Extrapolating out to the virial radius, we
obtain a virial mass for the MW of 6.82x1011M☉ with 50%
credible region of (6.06,7.53)x1011M☉ (rvir=185-7+7kpc).
If we consider only the GCs beyond 10 kpc, then the virial mass is
9.02(5.69,10.86)x1011M☉ (rvir=198-24+19kpc). We also
arrive at an estimate of the velocity anisotropy parameter β of
the GC population, which is β=0.28 with a 50% credible region
(0.21, 0.35). Interestingly, the mass estimates are sensitive to both
the dark matter halo potential and visible matter tracer parameters,
but are not very sensitive to the anisotropy parameter.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 107 157 *Kinematic data of Galactic globular clusters
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Note on table1.dat: All the kinematic data available for 157 Milky Way (MW)
globular clusters (GCs), using the catalog of Harris (1996, VII/202;
2010arXiv1012.3224H 2010arXiv1012.3224H) as a starting point.
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See also:
VII/202 : Globular Clusters in the Milky Way (Harris, 1997)
J/MNRAS/450/2692 : Param. of galactic globular clusters (Vanderbeke+, 2015)
J/A+A/562/A134 : Tracers of the Milky Way mass (Bratek+, 2014)
J/ApJ/684/1143 : BHB candidates in the Milky Way (Xue+, 2008)
J/A+A/450/105 : Properties of 153 Galactic globular clusters (Bica+, 2006)
J/A+A/397/899 : Proper motions of field HB stars (Sakamoto+, 2003)
J/A+A/385/67 : HST VI phot. & proper motions in NGC 6528 (Feltzing+, 2002)
http://www.astro.yale.edu/dana/gc.html : Globular clusters compilation
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- ID Milky Way globular cluster identifier
11- 15 F5.1 kpc Rgc [0.5/125] Harris catalog Galactocentric
distance
17- 23 F7.3 mas/yr pmRA [-12.7/7.4]? Proper motion along
Right Ascension times cos(DE)
25- 29 F5.3 mas/yr e_pmRA [0.03/2]? Uncertainty in pmRA*cosDE
31- 38 F8.4 mas/yr pmDE [-19.4/5.4]? Proper motion along Declination
40- 44 F5.3 mas/yr e_pmDE [0.03/1.8]? Uncertainty in pmDE
46- 51 F6.1 km/s VLOS [-411.4/494]? Harris catalog Heliocentric
line-of-sight velocity
53- 56 F4.1 km/s e_VLOS [0.1/57]? Uncertainty in VLOS
58- 62 F5.2 --- cos(xi) [-1/1] Cosine of angle subtended by Sun, GC,
and Galactic center
64- 84 A21 --- Ref Proper motion reference (1)
86 A1 --- Incl? Included in sample; x=Yes
88-107 A20 --- n_Incl? Note
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Note (1): References as follows:
Cioni = 2016A&A...586A..77C 2016A&A...586A..77C;
Casseti = 2013AJ....146...33C 2013AJ....146...33C, 2010AJ....140.1282C 2010AJ....140.1282C,
1999AJ....117.1792D 1999AJ....117.1792D, 2004AJ....128..687D 2004AJ....128..687D, and
2005ApJ...631L..49D 2005ApJ...631L..49D;
Feltzing and Johnson = 2002, J/A+A/385/67;
Fritz = 2015ApJ...811..123F 2015ApJ...811..123F;
Kupper = 2015ApJ...803...80K 2015ApJ...803...80K;
Majewski and Cudworth = 1993PASP..105..987M 1993PASP..105..987M;
Massari = 2013ApJ...779...81M 2013ApJ...779...81M;
Rossi = 2015MNRAS.450.3270R 2015MNRAS.450.3270R;
Wang = 2005ChA&A..29..386W 2005ChA&A..29..386W;
Zoccali = 2001AJ....121.2638Z 2001AJ....121.2638Z.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 14-Dec-2016