J/ApJ/798/23 Radial velocities of giant stars in NGC 6388 (Lapenna+, 2015)
Radial velocities from VLT-KMOS spectra of giant stars in the globular cluster
NGC 6388.
Lapenna E., Origlia L., Mucciarelli A., Lanzoni B., Ferraro F.R.,
Dalessandro E., Valenti E., Cirasuolo M.
<Astrophys. J., 798, 23 (2015)>
=2015ApJ...798...23L 2015ApJ...798...23L
ADC_Keywords: Clusters, globular ; Stars, giant ; Radial velocities ;
Photometry, infrared ; Photometry, HST
Keywords: globular clusters: individual: NGC 6388; techniques: spectroscopic ;
instrumentation: spectrographs; stars: kinematics and dynamics
Abstract:
We present new radial velocity measurements for 82 stars, members of
the Galactic globular cluster (GC) NGC 6388, obtained from ESO-VLT
K-band Multi Object Spectrograph (KMOS) spectra acquired during the
instrument Science Verification. The accuracy of the wavelength
calibration is discussed and a number of tests of the KMOS response
are presented. The cluster systemic velocity obtained (81.3±1.5km/s)
is in very good agreement with previous determinations. While a hint
of ordered rotation is found between 9" and 20" from the cluster
center, where the distribution of radial velocities is clearly
bimodal, more data are needed before drawing any firm conclusions. The
acquired sample of radial velocities has also been used to determine
the cluster velocity dispersion (VD) profile between ∼9" and 70",
supplementing previous measurements at r<2" and r>60" obtained with
ESO-SINFONI and ESO-FLAMES spectroscopy, respectively. The new portion
of the VD profile nicely matches the previous ones, better defining
the knee of the distribution. The present work clearly shows the
effectiveness of a deployable integral field unit in measuring the
radial velocities of individual stars for determining the VD profile
of Galactic GCs. It represents the pilot project for an ongoing large
program with KMOS and FLAMES at the ESO-VLT, aimed at determining the
next generation of VD and rotation profiles for a representative
sample of GCs.
Description:
During the instrument Science Verification (SV) run, under proposal
60.A-9448(A) (PI: Lanzoni - June 2013), we used ESO-VLT/KMOS multiple
pointings to investigate the region within ∼9" and 70" from the center
of NGC 6388. We have used the KMOS YJ grating and observed in the
1.00-1.35um spectral range at a resolution R∼3400.
The spectroscopic targets have been selected from near-IR data
acquired with SOFI at the ESO-NTT, based on the star position in the
color-magnitude diagrams (CMD) and the radial distribution within the
cluster.
We used Advanced Camera for Surveys-Hubble Space Telescope (HST/ACS)
data in the V and I bands, from Lanzoni et al. (2007ApJ...668L.139L 2007ApJ...668L.139L),
Sarajedini et al. (2007AJ....133.1658S 2007AJ....133.1658S), and Dalessandro et al. (2008,
J/ApJ/677/1069), to identify additional stars not present in the SOFI
catalog.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 75 82 Individual giant stars in NGC 6388 (within 70")
observed with KMOS
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See also:
B/eso : ESO Science Archive Catalog (ESO, 1991-2015)
B/hst : HST Archived Exposures Catalog (STScI, 2007)
VII/202 : Globular Clusters in the Milky Way (Harris, 1997)
J/A+A/573/A103 : Light curves for variables in 5 clusters (Skottfelt+, 2015)
J/A+A/563/A80 : Wide field imagers astrometry. V. (Libralato+, 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/A+A/533/A36 : VI phot. and velocity map of NGC 6388 (Luetzgendorf+, 2011)
J/MNRAS/402/1729 : JHK photometry of 36 Galactic GCs (Valenti+ 2010)
J/A+A/524/A44 : CN and CH line strengths in 12 globulars (Pancino+, 2010)
J/ApJ/677/1069 : Blue stragglers in NGC 6388 (Dalessandro+, 2008)
J/A+A/464/967 : Abundances of red giants in NGC 6388 (Carretta+, 2007)
J/AJ/134/229 : CT1T2 Photometry of red giants in 2 globulars (Hughes+, 2007)
J/AJ/133/1287 : JHK phot. of 24 Galactic globular clusters (Valenti+, 2007)
J/ApJS/161/304 : Star clusters in the MW and satellites (McLaughlin+, 2005)
J/A+A/324/505 : Core velocity dispersions of globular clusters (Dubath+ 1997)
J/AJ/109/218 : Catalogue of globular cluster profiles (Trager+ 1995)
J/AJ/107/1764 : RR Lyrae and CMD of NGC 6388 (Silbermann+, 1994)
http://www.cosmic-lab.eu/Cosmic-Lab : Cosmic-Lab home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- [LOM2015] [28786/325164] Identification number
8- 18 F11.7 deg RAdeg Right ascension (J2000)
20- 30 F11.7 deg DEdeg Declination (J2000)
32- 36 F5.2 mag Vmag [14.4/17.4] HST V-band magnitude
38- 42 F5.2 mag Imag [11.8/15.9] HST I-band magnitude
44- 48 F5.2 mag Jmag [9.9/13.0]?=0 ESO-NTT/SOFI J-band magnitude
50- 54 F5.2 mag Ksmag [8.6/12.1]?=0 ESO-NTT/SOFI Ks-band magnitude
56- 60 F5.1 km/s RV [56/123] Radial velocity (Vr)
62- 65 F4.1 km/s e_RV [0.1/13] RV uncertainty
67- 71 A5 --- IFU KMOS IFU identification number(s) (1)
73- 75 A3 --- Np Pointing numbers (1)
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Note (1): Two values are marked for the 12 targets observed twice.
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Acknowledgements:
Emilio Lapenna (University of Bologna)
(End) Emmanuelle Perret [CDS] 21-May-2015