J/ApJ/950/138 Kinematic catalog of stars in NGC 6569 (Pallanca+, 2023)
Internal kinematics and structure of the bulge globular cluster NGC 6569.
Pallanca C., Leanza S., Ferraro F.R., Lanzoni B., Dalessandro E.,
Cadelano M., Vesperini E., Origlia L., Mucciarelli A., Valenti E.,
Miola A.
<Astrophys. J., 950, 138 (2023)>
=2023ApJ...950..138P 2023ApJ...950..138P
ADC_Keywords: Clusters, globular; Radial velocities; Photometry, HST;
Spectra, infrared; Optical; Magnitudes; Surveys
Keywords: Globular star clusters ; Stellar dynamics ; Stellar kinematics ;
Spectroscopy
Abstract:
In the context of a project aimed at characterizing the properties of
star clusters in the Galactic bulge, here we present the determination
of the internal kinematics and structure of the massive globular
cluster NGC 6569. The kinematics has been studied by means of an
unprecedented spectroscopic data set acquired in the context of the
ESO-VLT Multi-Instrument Kinematic Survey of Galactic globular
clusters, combining the observations from four different
spectrographs. We measured the line-of-sight velocity of a sample of
almost 1300 stars distributed between ∼0.8" and 770" from the cluster
center. From a subsample of high-quality measures, we determined the
velocity dispersion profile of the system over its entire radial
extension (from ∼5" to ∼200" from the center), finding the
characteristic behavior usually observed in globular clusters, with a
constant inner plateau and a declining trend at larger radii. The
projected density profile of the cluster has been obtained from
resolved star counts, by combining high-resolution photometric data in
the center, and the Gaia EDR3 catalog radially extended out to ∼20'for
a proper sampling of the Galactic field background. The two profiles
are properly reproduced by the same King model, from which we
estimated updated values of the central velocity dispersion, main
structural parameters (such as the King concentration, the core, half
mass, and tidal radii), total mass, and relaxation times. Our analysis
also reveals a hint of ordered rotation in an intermediate region of
the cluster (40"<r<90", corresponding to 2rc<r<4.5rc), but
additional data are required to properly assess this possibility.
Description:
To build the velocity dispersion profile of NGC 6569 we used a
multi-instrument approach combining the radial velocity (RV)
measurements obtained from four different spectroscopic data sets;
based on observations collected at the European Southern Observatory,
Cerro Paranal (Chile), in the context of the ESO-VLT Multi-Instrument
Kinematic Survey (MIKiS survey) under Large Programmes 106.21N5
(PI: Ferraro), 195.D-0750 (PI: Ferraro), 193.D-0232 (PI: Ferraro).
The innermost cluster regions were sampled mainly by using the
AO-assisted integral field spectrograph MUSE at ESO-VLT in the narrow
field mode (NFM). This is the MUSE configuration that provides the
highest spatial resolution. MUSE provides a wavelength coverage from
4800Å to 9300Å, with a resolving power R∼3000 at λ∼8700Å.
Our data set has been collected as part of the ESO Large Program ID:
106.21N5.003 (PI: Ferraro) with seven pointings on 2021-08-16, -21 and
2022-09-27.
To sample the innermost regions, we also used an additional
spectroscopic data set acquired with the NIR (1.1-2.45um) AO-assisted
integral field spectrograph SINFONI at the ESO-VLT. The observations
(ESO Large program ID: 195.D-0750(A), PI: Ferraro) were performed with
the K-band grating, which samples the wavelength range 1.95-2.45um and
provides a spectral resolution R∼4000. The data set includes eight
pointings (spanning 2015-08-02 to 2016-07-22) covering a region of
∼15" from the cluster center.
The cluster region at intermediate distances from the center has been
sampled by using the integral field spectrograph KMOS at the ESO-VLT.
The data have been acquired under the ESO Large Program ID: 193.D-0232
(PI: Ferraro) adopting the YJ grating, which samples the 1.025-1.344um
spectral range at a resolution R∼3400. The data set includes nine
pointings on 2015-04-30, 2015-05-02 and 2015-05-03.
To investigate the cluster kinematics in the outermost cluster regions
we used the fiber-fed multi-object spectrograph FLAMES in the
GIRAFFE/MEDUSA mode. The observations have been executed adopting the
HR21 and HR13 grating setups (ESO Large Program ID: 193.D-0232(F), PI:
Ferraro, and ID: 093.D-0286(A), PI: Villanova, respectively). The HR13
data set samples the spectral range 6120-6405Å with a resolving
power R∼26400 and consists of two repeated exposures (each 2775s long
p, 2014-06/19 and 2014-08-01) of the same targets. The HR21 grating
provides a resolving power R∼18000 sampling the wavelength range
between 8484 and 9001Å (spanning 2015-06-22 to 2015-07-26).
For a proper analysis of the density and RV distributions of stars in
NGC 6569, the first step is the determination of the center of gravity
of the cluster. To this aim, we used the photometric catalog described
in Saracino+ (2019ApJ...874...86S 2019ApJ...874...86S). This is based on F555W and F814W
images obtained from high-resolution Hubble Space Telescope (HST)/WFC3
observations and a set of J- and Ks -band images acquired with the
Gemini Multi-Conjugate Adaptive Optics System (GeMS).
See Section 3.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
18 13 38.70 -31 49 37.13 NGC 6569 = ESO 456-77
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 63 1073 *kinematic catalog of the quality selected stars
(S/N>15 and RV error <5km/s) in NGC 6569
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Note on table4.dat: The kinematic catalog reports the identification number,
the absolute coordinates, the optical and NIR magnitudes (if
available), and the measured line-of-sight velocities and errors for
all the stars surviving the quality selection criteria. No membership
selection is applied.
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See also:
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
VII/195 : Globular Clusters in the Milky Way (Harris, 1996)
VII/202 : Globular Clusters in the Milky Way (Harris, 1997)
VII/233 : 2MASS All-Sky Extended Source Catalog (XSC) (IPAC/UMass, 2003-2006)
J/ApJS/161/304 : Star clusters in the MW and satellites (McLaughlin+, 2005)
J/MNRAS/361/272 : JHKs phot. of 4 Bulge globular clusters (Valenti+, 2005)
J/A+A/450/105 : Properties of 153 Galactic globular clusters (Bica+, 2006)
J/AJ/131/2114 : Radial velocities in Fornax dSph (Walker+, 2006)
J/MNRAS/380/281 : Faint galactic satellites sp. survey (Martin+, 2007)
J/AJ/133/1287 : JHK phot. of 24 Galactic globular clusters (Valenti+, 2007)
J/MNRAS/396/2183 : RVels of red giants in ω Cen (Sollima+ 2009)
J/MNRAS/402/1729 : JHK phot. of 36 Galactic globular clusters (Valenti+ 2010)
J/ApJ/726/L20 : Spectroscopy of Terzan 5 (Origlia+, 2011)
J/ApJ/769/107 : RVs and [Fe/H] of star members of NGC 6388 (Lanzoni+, 2013)
J/ApJ/795/22 : Iron abundance of Terzan 5 stars (Massari+, 2014)
J/ApJ/798/23 : Rvels of giant stars in NGC 6388 (Lapenna+, 2015)
J/MNRAS/478/1520 : Milky Way globular clusters data (Baumgardt+, 2018)
J/AJ/155/71 : Members of the bulge cluster NGC 6569 (Johnson+, 2018)
J/ApJ/861/99 : HSTPROMO cat. VI. Analysis of NGC362 (Libralato+, 2018)
J/MNRAS/505/5978 : Gaia EDR3 view on Gal. globular clusters (Vasiliev+, 2021)
http://www.cosmic-lab.eu/Cosmic-Lab/MIKiS_Survey.html : The MIKiS Survey of
Galactic globular clusters homepage
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Seq [1/1073] Sequential identifier used in this work
6- 16 F11.7 deg RAdeg [273.2/273.7] Right Ascension (ICRS) at
Epoch=2016.0
18- 28 F11.7 deg DEdeg [-32.1/-31.6] Declination (ICRS) at Epoch=2016.0
30- 34 F5.2 mag F555Wm [14.8/21.14]?=99.99 HST/WFC3 F555W (Vega)
magnitude
36- 40 F5.2 mag F814Wm [12.4/19.8]?=99.99 HST/WFC3 F814W (Vega)
magnitude
42- 46 F5.2 mag Jmag [9.4/18.8]?=99.99 Gemini/GeMS J band (Vega)
magnitude
48- 52 F5.2 mag Ksmag [8/14.8]?=99.99 Gemini/GeMS Ks band (Vega)
magnitude
54- 59 F6.1 km/s RVel [-233/228] MIKiS Survey radial (line of sight)
velocity
61- 63 F3.1 km/s e_RVel [0.2/5] Uncertainty in RVel
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 04-Aug-2025