J/MNRAS/494/4548 Internal kinematics of M10 and M71 (Barth+, 2020)
Internal kinematics of M10 and M71.
Barth N.A., Gerber J.M., Boberg O.M., Friel E.D., Vesperini E.
<Mon. Not. R. Astron. Soc., 494, 4548-4557 (2020)>
=2020MNRAS.494.4548B 2020MNRAS.494.4548B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, giant ; Clusters, globular ; Positional data ;
Radial velocities ; Photometry ; Spectroscopy ; Optical
Keywords: stars: kinematics and dynamics - globular clusters: general -
globular clusters: individual: (M10-M71)
Abstract:
We present a study of the internal kinematics of two globular
clusters, M10 (NGC 6254) and M71 (NGC 6838), using individual radial
velocity (RV) measurements obtained from observations using the Hydra
multiobject spectrograph on the WIYN 3.5m telescope. We measured 120
RVs for stars in M10, of which 107 were determined to be cluster
members. In M71, we measured 82 RVs and determined 78 of those
measurements belonged to cluster members. Using the cluster members,
we determine a mean RV of 75.9±4.0 (s.d.) km/s and -22.9±2.2
(s.d.) km/s for M10 and M71, respectively. We combined the Hydra RV
measurements with literature samples and performed a line-of-sight
rotational analysis on both clusters. Our analysis has not revealed a
statistically significant rotation in either of these clusters with
the exception of the inner region (10-117arcsec) of M10 for which we
find hints of a marginally significant rotation with amplitude
Vrot=1.14±0.18km/s. For M10, we calculate a central velocity
dispersion of σ0=5.44±0.61km/s, which gives a ratio of the
amplitude of rotation to the central velocity dispersion
Vrot/σ0=0.21±0.04. We also explored the rotation of the
multiple stellar populations identified in M10 and M71 and found
rotation (or lack thereof) in each population consistent with each
other and the cluster global rotation signatures.
Description:
Using the Hydra multiobject spectrograph at the
Wisconsin-Indiana-Yale-NOAO (WIYN) 3.5m telescope, we obtained
observations of stars in M10 and M71 on two separate observing runs:
2016 June 24 and 2017 June 11-13. We used echelle grating '316@63.4'
for a dispersion of 0.16Å/pix (7.7km/s/pix), over the wavelength
range from 6030Å to 6350Å. Multiple exposures of a star's
spectrum were combined into a single spectrum that was used for RV
measurements. RV standards were also observed on both the 2016 and
2017 observing runs (HD182488, HD194071, and HD212943).
One of the main goals of this work was to explore any possible
differences in the kinematics between the two populations that are
known to exist in each cluster. While the radial velocities measured
by Carretta et al. (2009A&A...505..117C 2009A&A...505..117C, Cat. J/A+A/505/117,
2009A&A...505..139C 2009A&A...505..139C, Cat. J/A+A/505/139) in M10 come from
high-resolution spectroscopy and are precise enough to use to
determine population kinematics such as rotation, the studies by
Gerber et al. (2018AJ....156....6G 2018AJ....156....6G, Cat. J/AJ/156/6) and Gerber et al.
(2020AJ....159...50G 2020AJ....159...50G, Cat. J/AJ/159/50) used low-resolution
spectroscopy to classify stars based on molecular CN band features.
These low resolution radial velocities do not have the precision
necessary to measure the relatively small rotation signatures observed
in GCs. Therefore, our main sample focused on observing stars in M10
and M71 that had classification information from Gerber et al.
(2018AJ....156....6G 2018AJ....156....6G, Cat. J/AJ/156/6; 2020AJ....159...50G 2020AJ....159...50G, Cat.
J/AJ/159/50), but required high resolution follow up to determine more
precise radial velocities.
Objects:
---------------------------------------------------------------------
RA (ICRS) DE Designation(s)
---------------------------------------------------------------------
16 57 09.05 -04 06 01.0 M 10 = C 1654-040 = GCRV 68711 = GCl 49
19 53 46.48 +18 46 45.0 M 71 = C 1951+186 = GCRV 12241 = GCl 115
---------------------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 50 120 M10 Hydra Data
table2.dat 51 82 M71 Hydra Data
--------------------------------------------------------------------------------
See also:
J/ApJ/628/729 : CCD BVIc photometry of M10 stars (Pollard+, 2005)
J/A+A/505/117 : Abundances of red giants in 15 globular clusters
(Carretta+, 2009)
J/A+A/505/139 : Abundances of red giants in 17 globular clusters
(Carretta+, 2009)
J/AJ/156/6 : Light element abundances of RGB & AGB stars in M10
(Gerber+, 2018)
J/AJ/159/50 : Identifying multiple populations in M71 using CN
(Gerber+, 2020)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- ID [9/2553] Star identifier from Pollard et al.
(2005ApJ...628..729P 2005ApJ...628..729P, Cat. J/ApJ/628/729)
6- 14 F9.5 deg RAdeg Right ascension (J2000)
16- 23 F8.5 deg DEdeg Declination (J2000)
25- 29 F5.2 mag Vmag V-band magnitude
31- 34 F4.2 mag B-V B-V color index
36- 41 F6.2 km/s RV Radial velocity
43- 46 F4.2 km/s e_RV Error on RV
48 A1 --- Pop [0/2] Star population (1)
50 A1 --- Memb [y/n] Indicates if the star is a member of the
M10 cluster
--------------------------------------------------------------------------------
Note (1): Population as follows:
1 = First Generation stars
2 = Second Generation Stars
0 = No information about the star's population (Carretta et al.
2009A&A...505..117C 2009A&A...505..117C, Cat. J/A+A/505/117, 2009A&A...505..139C 2009A&A...505..139C,
Cat. J/A+A/505/139; Gerber et al. 2018AJ....156....6G 2018AJ....156....6G, Cat. J/AJ/156/6)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- ID Star identifier from Cudworth
(1985AJ.....90...65C 1985AJ.....90...65C)
8- 16 F9.5 deg RAdeg Right ascension (J2000)
18- 25 F8.5 deg DEdeg Declination (J2000)
27- 31 F5.2 mag Vmag V-band magnitude
33- 36 F4.2 mag B-V B-V color index
38- 42 F5.1 km/s RV Radial velocity
44- 47 F4.2 km/s e_RV Error on RV
49 A1 --- Pop [0/2] Star population (1)
51 A1 --- Memb [y/n] Indicates if the star is a member of the
M71 cluster
--------------------------------------------------------------------------------
Note (1): Population as follows:
1 = First Generation stars
2 = Second Generation Stars
0 = No information about the star's population (Gerber et al.
2020AJ....159...50G 2020AJ....159...50G, Cat. J/AJ/159/50)
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 01-Jun-2023