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J/ApJ/454/788       Radial velocities and BV photometry of NGC 3201 (Cote+ 1995)

Dynamics of the Galactic globular cluster NGC 3201 Cote P., Welch D.L., Fischer P., Gebhardt K. <Astrophys. J. 454, 788 (1995)> =1995ApJ...454..788C (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Radial velocities ; Photometry, CCD Keywords: globular clusters: individual (NGC 3201) - stars: kinematics - techniques: radial velocities Abstract: BV CCD frames have been used to derive surface brightness profiles for NGC 3201 which extend out to ∼18'. A total of 857 radial velocities with median precision ∼1km/s for 399 member giants have been used to trace the velocity dispersion profile out to 32.1' (the approximate tidal radius determined from fits of single-mass, isotropic King-Michie models to the cluster surface brightness profiles). The median difference in radial velocity for stars on either side of an imaginary axis stepped through the cluster in 1 deg increments shows a statistically significant maximum amplitude of 1.22±0.25km/s. We discuss several possible explanations of this result, including (1) cluster rotation, (2) preferential stripping of stars on prograde orbits near the limiting radius, (3) the projection of the cluster space velocity onto the plane of the sky, and (4) a slight drift in the velocity zero point. It is difficult to unambiguously identify the primary cause of the observed structure in the velocity field, however, and we suspect that all of the above processes may play a role. The BV surface brightness profiles and radial velocities have been modeled with both single- and multimass King-Michie models and nonparametric techniques. The corresponding density profiles and M/L profiles show good agreement over the interval 1.5≲R≲10pc, and both approaches suggest a steady rise in M/L with distance from the cluster center. Due to the low cluster luminosity we are unable to place useful constraints on the anisotropy of M/LB∼M/LV∼2.0±0.2 for the multimass and nonparametric models, compared to ∼1.65±0.15 for models having equal-mass stars. Our best-fit, multimass models have mass function slopes of x∼0.75±0.25, consistent with recent findings that the form of the mass function depends on the position relative to the potential of the Galaxy. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table3 121 930 Radial velocities and photometry
Byte-by-byte Description of file: table3
Bytes Format Units Label Explanations
1- 3 I3 --- Star Star identification number 6- 7 I2 h RAh Right ascension, equinox=J2000.0 9- 10 I2 min RAm Right ascension 11- 16 F6.2 s RAs Right ascension 18 A1 --- DE- Declination sign 19- 20 I2 deg DEd Declination, equinox=J2000.0 22- 23 I2 arcmin DEm Declination 25- 28 F4.1 arcsec DEs Declination 30- 35 F6.2 arcmin Dist Distance from cluster center 38- 49 F12.4 d HJD HJD of radial velocity 52- 57 F6.2 km/s HRV Heliocentric radial velocity 60- 63 F4.2 km/s e_HRV HRV uncertainty 66- 71 F6.2 km/s HRVmean Weighted mean heliocentric radial velocity 74- 77 F4.2 km/s e_HRVmean HRVmean uncertainty 80- 84 F5.2 mag Vmag Apparent V magnitude 87- 90 F4.2 mag B-V Apparent B-V color 93- 94 I2 --- o_HRV Number of radial velocity measurements 96-101 F6.2 --- Chi2 Chi-square for radial velocities 103-108 F6.2 --- Chi2_R []? Reduced chi-square for radial velocities 111-116 F6.4 --- Prob [0/1]? Probability of obtaining a chi-square this large purely as a consequence of measurement error 119-121 A3 --- Src Source of photometry, 'APM' or 'CCD'
Origin: AAS CD-ROM series, Volume 5, 1995 Lee Brotzman [ADS] 05-Nov-95
(End) Patricia Bauer [CDS] 24-Oct-1996
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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