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J/AJ/110/1699          F-P observations of globular clusters (Gebhardt+ 1995)

Fabry-Perot observations of globular clusters. II. 47 Tuc, NGC 6397, and M30 Gebhardt K., Pryor C., Williams T.B., Hesser J.E. <Astron. J. 110, 1699 (1995)> =1995AJ....110.1699G
ADC_Keywords: Clusters, globular ; Radial velocities Abstract: Using the Rutgers Imaging Fabry-Perot Spectrophotometer on the CTIO 4-m telescope, we have measured radial velocities for 548 stars in 47 Tuc (NGC 104), 128 stars in NGC 6397, and 132 stars in M30 (NGC 7099), with uncertainties between 0.5 and 5km/s. In 47 Tuc and NGC 6397, the dispersion profiles at first increase with decreasing radii but then flatten in the central 0.4'. This is the same behavior seen in our previously published profile for M15. The measured stellar velocities show that 47 Tuc is rotating, with a projected rotation axis that is aligned with the isophotal minor axis. We also find a similar alignment for the rotation that we previously measured in M15. A map of the average velocity in the central regions derived from the integrated light shows rotation for NGC 6397 and 47 Tuc. For 47 Tuc, NGC 6397, and M15, the amplitude of the projected rotation measured at a radius of 0.6' using the individual stellar velocities is equal to, or smaller than, that measured at a radius of 0.2' using the integrated light. This is not consistent with the solid-body rotation usually assumed for the inner regions. To study further the form of the projected rotation we have used two-dimensional spline smoothing to derive a mean velocity map for 47 Tuc using the individual stellar velocities. This map shows that the projected rotation velocity reaches a plateau at a radius of 3' and that the radial dependence of the projected rotation velocity deviates significantly from solid body beyond 2'. We have repeat measurements of the two "high-velocity" stars of Meylan, Dubath, and Mayor. However, we detect more stars with similar large offsets from the cluster mean velocity. The number of stars that we measure with large velocity offsets is consistent with a normal distribution, so that there is no need to invoke a special creation mechanism for these stars. Objects: ---------------------------------------------------------- RA (2000) DE Designation(s) ---------------------------------------------------------- 00 23.4 -72 04 47 Tuc = NGC 104 17 40.9 -53 41 NGC 6397 21 40.3 -23 11 M 30 = NGC 7099 ---------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1a 47 802 47 Tuc stars table1b 47 132 M30 stars table1c 47 126 NGC 6397 stars
See also: 1993BAAS...25Q1406P : Fabry-Perot observations of globular cluster cores. J/AJ/113/1026 : Fabry-Perot Observations of M15 (Gebhardt+ 1997) Byte-by-byte Description of file: table1?
Bytes Format Units Label Explanations
1- 5 A5 --- ID Star identification (1) 7- 12 F6.1 arcsec Xpos []? X offset from adopted cluster center (2) 14- 19 F6.1 arcsec Ypos []? Y offset from adopted cluster center (2) 21- 25 F5.1 mag Vmag []? Fabry-Perot V magnitude (3) 27- 32 F6.1 km/s Vel Velocity 34- 37 F4.1 km/s e_Vel Velocity uncertainty (4) 39- 47 A9 --- Note Notes (5)
Note (1): When a star has many entries, the first line is the weighted mean and subsequent lines are the individual velocity Identification prefixes are: FP Fabry-Perot number M Mayor et al. (1983A&AS...54..495M) MDM Meylan et al. (1991ApJ...383..587M) CA Cordoni & Auriere (1984A&AS...58..559C) AW Alcaino & Wamsteker (1982A&AS...50..141A) W Wooley et al. (1961RGOB...43....1W) V Sawyer-Hogg (1973PDDO....3....6S) Note (2): Offset in arcseconds from the adopted cluster center, increasing to the E and N, respectively. These centers are the location of the peak value of an adaptive kernel estimate (Silverman 1986, Density Estimation for Statistics and Data Analysis; Chapman and Hall, London) of the surface density of stars identified in our frames by DAOPHOT and have uncertainties of approximately 2". For 47 Tuc the adopted center is within 2" of the center defined by Guhathakurta et al. 1992AJ....104.1790G. Plausible errors in the adopted centers have little effect on the dynamical analysis. The relative offsets for the stellar positions are good to within 0.1". Note (3): The FP V magnitude should only be used as a rough estimate since a ∼4A bandpass was used and no color terms were included when transforming the measured counts in continuum into a V magnitude. Note (4): The uncertainties for the 47 Tuc velocities do not include the additional 1km/s discussed in section 2 of the printed paper. Note (5): Additional IDs, the probability of the Chi-square exceeding the observed value when there are multiple velocity measurements, or the number "1" if the star is not used in the dynamical analysis due to restricted velocity coverage at the outer edge of the field.
Origin: AAS CD-ROM series, Volume 5, 1995 Lee Brotzman [ADS] 31-Oct-1995
(End) [CDS] 25-Jan-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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