J/MNRAS/482/5138 Galactic GC mean proper motions & velocities (Baumgardt+, 2019)
Mean proper motions, space orbits, and velocity dispersion profiles of
Galactic globular clusters derived from Gaia DR2 data.
Baumgardt H., Hilker M., Sollima A., Bellini A.
<Mon. Not. R. Astron. Soc., 482, 5138-5155 (2019)>
=2019MNRAS.482.5138B 2019MNRAS.482.5138B (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Clusters, globular ; Proper motions ;
Space velocities ; Radial velocities ; Stars, distances
Keywords: stars: luminosity function - mass function -
globular clusters: general
Abstract:
We have derived the mean proper motions and space velocities of 154
Galactic globular clusters and the velocity dispersion profiles of 141
globular clusters based on a combination of Gaia DR2 proper motions
with ground-based line-of-sight velocities. Combining the velocity
dispersion profiles derived here with new measurements of the internal
mass functions allows us to model the internal kinematics of 144
clusters, more than 90 per cent of the currently known Galactic
globular cluster population. We also derive the initial cluster masses
by calculating the cluster orbits backwards in time applying suitable
recipes to account for mass-loss and dynamical friction. We find a
correlation between the stellar mass function of a globular cluster
and the amount of mass lost from the cluster, pointing to dynamical
evolution as one of the mechanisms shaping the mass function of stars
in clusters. The mass functions also show strong evidence that
globular clusters started with a bottom-light initial mass function.
Our simulations show that the currently surviving globular cluster
population has lost about 80 per cent of its mass since the time of
formation. If globular clusters started from a lognormal mass
function, we estimate that the Milky Way contained about 500 globular
clusters initially, with a combined mass of about 2.5x108M☉.
For a power-law initial mass function, the initial mass in globular
clusters could have been a factor of three higher.
Description:
Our target list of globular clusters was taken from the 2010 edition
of Harris (1996AJ....112.1487H 1996AJ....112.1487H, Cat. VII/202), which lists 157
globular clusters. To this list we added the following three clusters
that have been found to be Globular clusters: Crater (Laevens et al.,
2014ApJ...786L...3L 2014ApJ...786L...3L), FSR 1716 (Minniti et al., 2017ApJ...838L..14M 2017ApJ...838L..14M),
and Mercer 5 (Mercer et al. 2005, Cat. J/ApJ/635/560; Longmore et al.,
2011MNRAS.416..465L 2011MNRAS.416..465L).
We are thus left with a sample of 156 globular clusters. For each of
these clusters we selected all Gaia stars within a circle of 1200
arcsec around the cluster centres given by either Goldsbury, Heyl &
Richer (2013ApJ...778...57G 2013ApJ...778...57G) or Harris (1996AJ....112.1487H 1996AJ....112.1487H, Cat.
VII/202). For IC 1257 and Ter 10 we found that the cluster centres
given in Harris (1996AJ....112.1487H 1996AJ....112.1487H, Cat. VII/202) were incorrect and
determined new centres from the positions of the member stars found in
the Gaia DR2 catalogue. For each globular cluster, we then
cross-correlated the Gaia positions against the catalogue of 40000
globular stars with line-of-sight velocity measurements compiled by
Baumgardt & Hilker (2018MNRAS.478.1520B 2018MNRAS.478.1520B) from published literature and
archival ESO and Keck spectra.
Parallaxes and proper motions derived from Gaia DR2 are superseded
by data derived from Gaia EDR3 in Vasiliev & Baumgardt,
2021MNRAS.505.5978V 2021MNRAS.505.5978V, Cat. J/MNRAS/505/5978
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 200 154 Mean proper motions and orbital parameters of
154 Galactic globular clusters.
See update with Gaia EDR3 in J/MNRAS/505/5978
table4.dat 48 319 Proper motion dispersion profiles of 102 globular
clusters derived from Gaia DR2 proper motions.
See update with Gaia EDR3 in J/MNRAS/505/5978
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/A+A/616/A12 : Gaia DR2 sources in GC and dSph (Gaia Collaboration+, 2018)
J/MNRAS/484/2832 : Milky Way globular clusters proper motions (Vasiliev, 2019)
J/MNRAS/505/5978 : Gaia EDR3 view on Galactic globular clusters
(Vasiliev+, 2021)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name Name of the cluster
14- 23 F10.6 deg RAdeg Right ascension (J2000)
25- 34 F10.6 deg DEdeg Declination (J2000)
36- 41 F6.2 kpc Rsun Distance to the Sun
43- 49 F7.2 km/s RV Mean radial velocity
51- 56 F6.2 mas/yr pmRA* Proper motion along RA, pmRA*cosDE
58- 63 F6.2 mas/yr pmDE Proper motion along DE
65- 69 F5.2 --- rho Correclation between pmRA and pmDE
72- 77 F6.2 kpc X X component of the cluster position
(from the Galactic centre towards the Sun)
79- 84 F6.2 kpc Y Y component of the cluster position
(in the direction of Galactic rotation at
the Solar position)
86- 91 F6.2 kpc Z Z component of the cluster position
(towards the North Galactic pole)
93- 99 F7.2 km/s U U component of the cluster velocity
(from the Galactic centre towards the Sun) (1)
101-107 F7.2 km/s V V component of the cluster velocity
(in the direction of Galactic rotation at
the Solar position) (1)
109-115 F7.2 km/s W W component of the cluster velocity
(towards the North Galactic pole) (1)
117-122 F6.2 kpc Rper Perigalactic distance of the cluster
124-129 F6.2 kpc Rapo Apogalactic distance of the cluster
131-134 F4.2 kpc e_Rsun ? rms uncertainty on Rsun
136-140 F5.2 km/s e_RV rms uncertainty on RV
142-145 F4.2 mas/yr e_pmRA* rms uncertainty on pmRA*
147-150 F4.2 mas/yr e_pmDE rms uncertainty on pmDE
152-155 F4.2 kpc e_X rms uncertainty on X
157-160 F4.2 kpc e_Y rms uncertainty on Y
162-166 F5.2 kpc e_Z rms uncertainty on Z
168-173 F6.2 km/s e_U rms uncertainty on U
175-180 F6.2 km/s e_V rms uncertainty on V
182-187 F6.2 km/s e_W rms uncertainty on W
189-193 F5.2 kpc e_Rper rms uncertainty on Rrper
195-200 F6.2 kpc e_Rapo rms uncertainty on Rapo
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Note (1): The velocities have been corrected for Galactic rotation and solar
motion relative to the LSR.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name Name of the cluster
16- 19 I4 --- NPM Number of stars used to calculate the proper
motion dispersion in each bin
21- 27 F7.2 arcsec r Average distance of stars from the
cluster centre
30- 34 F5.3 mas/yr sigma Proper motion dispersion
37- 41 F5.3 mas/yr E_sigma Error on sigma (upper value)
44- 48 F5.3 mas/yr e_sigma Error on sigma (lower value)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 11-Feb-2019