J/A+A/320/776 Tidal radii of 7 globular clusters (Lehmann+ 1997)
Tidal radii of the globular clusters M 5, M 12, M 13, M 15, M 53,
NGC 5053 and NGC 5466 from automated star counts.
Lehmann I., Scholz R.-D.
<Astron. Astrophys. 320, 776 (1997)>
=1997A&A...320..776L 1997A&A...320..776L (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular
Keywords: globular clusters: general - methods: statistical
Abstract:
We present new tidal radii for seven Galactic globular clusters using
the method of automated star counts on Schmidt plates of the
Tautenburg, Palomar and UK telescopes. The plates were fully scanned
with the APM system in Cambridge (UK). Special account was given to a
reliable background subtraction and the correction of crowding effects
in the central cluster region. For the latter we used a new kind of
crowding correction based on a statistical approach to the
distribution of stellar images and the luminosity function of the
cluster stars in the uncrowded area. The star counts were correlated
with surface brightness profiles of different authors to obtain
complete projected density profiles of the globular clusters. Fitting
an empirical density law (King 1962AJ.....67..471K 1962AJ.....67..471K) we derived the
following structural parameters: tidal radius rt, core radius rc and
concentration parameter c. In the cases of NGC 5466, M 5, M 12, M 13
and M 15 we found an indication for a tidal tail around these objects
(cf. Grillmair et al., 1995AJ....109.2553G 1995AJ....109.2553G).
Objects:
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RA (2000) DE Designation(s)
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15 18 33.7 +02 04 58 NGC 5904 = C 1516+022 = M 5
16 47 14.4 -01 56 52 NGC 6218 = C 1644-018 = M 12
16 41 41.4 +36 27 37 NGC 6205 = C 1639+365 = M 13
21 29 58.3 +12 10 00 NGC 7078 = C 2127+119 = M 15
13 12 55.1 +18 12 09 NGC 5024 = C 1310+184 = M 53
13 16 26.9 +17 41 52 NGC 5053 = C 1313+179
14 05 27.3 +28 32 04 NGC 5466 = C 1403+287
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table.dat 27 120 Star count
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Byte-by-byte Description of file: table.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name Cluster name
10- 14 F5.2 arcmin Rad Mean radius of an annulus
16- 21 F6.2 ct/arcmin2 Dens Background and crowding corrected stellar
density in number per arcmin2
23- 27 F5.2 ct/arcmin2 e_Dens uncertainty in Dens (number per arcmin2)
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Acknowledgements: Ingo Lehmann
(End) Patricia Bauer [CDS] 23-Feb-1998