J/A+A/688/A133 Internal kinematics of the core of M75 (Leanza+, 2024)
The ESO-VLT MIKiS survey reloaded: The internal kinematics of the core of M75.
Leanza S., Pallanca C., Ferraro F.R., Lanzoni B., Vesperini E., Cadelano M.,
Origlia L., Fanelli C., Dalessandro E., Valenti E.
<Astron. Astrophys. 688, A133 (2024)>
=2024A&A...688A.133L 2024A&A...688A.133L (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular; Radial velocities ; Optical
Keywords: techniques: radial velocities - techniques: spectroscopic -
stars: kinematics and dynamics -
globular star clusters: individual (NGC 6864)
Abstract:
We present the results of a study aimed at characterizing the
kinematics of the inner regions of the halo globular cluster M75 (NGC
6864) based on data acquired as part of the ESO-VLT Multi-Instrument
Kinematic Survey (MIKiS) of Galactic globular clusters. Our analysis
includes the first determination of the line-of-sight velocity
dispersion profile in the core region of M75. By using MUSE/NFM
observations, we obtained a sample of ∼1900 radial velocity
measurements from individual stars located within 16" (corresponding
to about r<3rc where rc is the estimated core radius of the
system) from the cluster center. After an appropriate selection of the
most accurate velocity measures, we determined the innermost portion
of the velocity dispersion profile, finding that it is characterized
by a constant behavior and a central velocity dispersion of
σ0∼9km/s. The simultaneous King model fitting to the projected
velocity dispersion and density profiles allowed us to check and
update previous determinations of the main structural parameters of
the system. We also detected a mild hint of rotation in the central
∼7" from the center, with an amplitude of just ∼1.0km/s and a position
angle of the rotation axis of PA0=174deg. Intriguingly, the position
angle is consistent with that previously quoted for the suspected
rotation signal in the outer region of the cluster. Taking advantage
of the high quality of the photometric catalog used for the analysis
of the MUSE spectra, we also provide updated estimates of the cluster
distance, age, and reddening.
Description:
The table contains the positions, radial velocities (RV) and
corresponding errors (eRV) of a sample of 630 individual stars (with
e_RV<5km/s and SNR>20) located in the central region of the globular
cluster NGC 6864 (M75), obtained from the analysis of MUSE/NFM data.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
ngc6864.dat 43 630 Positions and radial velocities of a sample
of 630 individual stars
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See also:
J/A+A/469/529 : UBVI photometry of NGC 6864 (Kravtsov+, 2007)
Byte-by-byte Description of file: ngc6864.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- ID Identification number
8- 18 F11.7 deg RAdeg Right ascension (J2000)
20- 30 F11.7 deg DEdeg Declination (J2000
32- 38 F7.2 km/s RV Radial velocity
40- 43 F4.2 km/s e_RV Radial velocity error
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Acknowledgements:
Silvia Leanza, silvia.leanza2(at)unibo.it
(End) Patricia Vannier [CDS] 03-Jun-2024