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J/ApJ/347/251        Dynamics of Globular Cluster M15     (Peterson+ 1989)

The Nonthermal Stellar Dynamics of the Globular Cluster M15 Peterson Ruth C., Seitzer Patrick, Cudworth Kyle M. <Astrophys. J. 347, 251 (1989)> =1989ApJ...347..251P
ADC_Keywords: Clusters, globular ; Radial velocities Keywords: clusters: globular - radial velocities - stars: stellar dynamics Abstract: The velocity dispersion as a function of radius in the globular cluster M15 is derived from measurements of 120 individual stars between 0.1' and 4.6' of the cluster center, and from the integrated light of the central cusp. The stellar measurements, with an individual accuracy of 1 km/s, indicate a mean cluster velocity of -107.1±0.9 km/s, and a mean velocity dispersion of 9.0±0.6 km/s. The velocity dispersion inside 1' varies with radius. The dispersion of the 27 stars within 20" is 14.2±1.9 km/s, while that of the 30 stars between 0.5' and 1.2' is 8.4±1.4 km/s. The cusp itself appears to have a dispersion of at least 25 km/s. Except for its greater velocity broadening, the spectrum of the integrated light of the cusp is indistinguishable from that formed by superposition of the individual M15 giant spectra, demonstrating that the excess light at the center is due primarily to the normal M15 population. The increase of the dispersion toward the center is not consistent with truncated isothermal (King-Michie) models, for which the velocity dispersion is nearly constant within a few core radii and then falls steeply beyond. The observed behaviour is difficult to reconcile as well with current post-core collapse models, which are also isothermal and whose central energy sources are modest. It is indicative of a nonthermal energy distribution with substantial heating in the central regions; this is consistent with a central black hole of about 1000 M. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 78 120 Velocities for M15 members table2.dat 38 87 Stars with multiple velocity measurements table3.dat 61 2 Velocities for M15 nonmembers
See also: J/AJ/106/154 : HST Observations in inner region of M15 (Ferraro+ 1993) J/AJ/107/1745 : HST UVI photometry of M5. II. (Yanny+, 1994) J/AJ/107/2067 : Fabry-Perot measurements of M15 (Gebhardt+, 1994) J/AJ/110/704 : RR Lyrae in M15 (Silbermann+ 1995) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 7 F7.2 d JD-2440000 *Julian date (-2440000) of each observation 9- 11 I3 h RAh *Right ascension (equinox 1950.0) 12- 14 I3 min RAm R.A. 15- 20 F6.2 s RAs R.A. 22 A1 --- DE- Declination sign (always blank) 23- 24 I2 deg DEd Declination (equinox 1950.0) 25- 27 I3 arcmin DEm Dec. 28- 32 F5.1 arcsec DEs Dec. 33- 38 F6.2 arcmin Dist *Radial distance from cluster center 39- 44 F6.1 deg PA *Position angle positive north through east 45- 53 F9.2 km/s RV *Measured radial velocity 54- 57 F4.1 km/s e_RV Internal uncertainty in RV 58- 64 F7.2 mag Vmag *[]? V magnitude 65- 70 I6 --- Kustner []? Number from Kustner (1921VeUSB..15....1K) 72- 78 A7 --- Other *Other star name
Note on JD-2440000: Mean Julian date of each observation, except for stars observed more than once, where the date of the first observation is listed. Note on RAh: Equatorial coordinates are as measured by Cudworth, except that AC [Auriere & Cordoni 1981, A&AS, 46, 347] coordinates were used for their stars 271, 417, 456, 457, 488, 576, 623, 780, and 787. Note on Dist, PA: Radius and position angle from the point marked by the large cross in Figure 1 of the printed paper, RA = 21h 27m 33.33s, DE=+11d 56m 48.8s Note on RV: For all multiply-observed stars, this is the weighted mean of the N independent observations in Table 2, except for K912, where the velocity and uncertainty were derived from the single spectrum formed by coadding the two separate exposures. Note on Vmag: V magnitude, from preliminary measurements by Cudworth except for stars inside 0.35', where AC values are used. Note on Other: Other star name: Auriere & Cordoni (1981A&AS...46..347A) prefix AC; Sandage (1970ApJ...162..841S) prefix S; Arp (1955AJ.....60..317A) Roman numeral prefix.
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 7 F7.2 d JD-2440000 Julian date (-2440000) 10- 17 F8.2 km/s RV Measured radial velocity 18- 23 F6.1 km/s e_RV Internal uncertainty in RV 25- 30 I6 --- Kustner []? Number from Kustner (1921VeUSB..15....1K) 32- 38 A7 --- Other *Other star name
Note on Other: Other star name: Auriere & Cordoni (1981A&AS...46..347A) prefix AC; Arp (1955AJ.....60..317A) Roman numeral prefix.
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 7 F7.2 d JD-2440000 Julian date (-2440000) of each observation 9- 11 I3 h RAh Right ascension (equinox 1950.0) 12- 14 I3 min RAm R.A. 15- 20 F6.2 s RAs R.A. 22 A1 --- DE- Declination sign (always blank) 23- 24 I2 deg DEd Declination (equinox 1950.0) 25- 27 I3 arcmin DEm Dec. 28- 32 F5.1 arcsec DEs Dec. 33- 41 F9.2 km/s RV Measured radial velocity 42- 46 F5.1 km/s e_RV Internal uncertainty in RV 47- 53 F7.2 mag Vmag V magnitude 56- 61 I6 --- Kustner Number from Kustner (1921VeUSB..15....1K)
References: Kustner F., 1921, Veroff. Sternw. Bonn, No 15 =1921VeUSB..15....1K Origin: AAS CD-ROM series, Volume 4, 1995 Lee Brotzman [ADS] 06-May-1995
(End) [CDS] 11-Jul-1995
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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