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J/AJ/109/639              The Core of NGC 6624                     (Sosin+ 1995)

HST Observations of the Core of the Globular Cluster NGC 6624 Sosin C., King I.R. <Astron. J. 109, 639 (1995)> =1995AJ....109..639S
ADC_Keywords: Clusters, globular; Photometry; Positional data Abstract: We have used the Faint Object Camera on the Hubble Space Telescope (HST) to observe three fields near the center of the post-collapse globular cluster NGC 6624 in B and V. We use individual stellar positions and a maximum-likelihood technique to measure a position for the cluster center. We then transfer this position and the position of the x-ray source 4U 1820-30 to right ascension and declination, and correct an error of 1.8" in an earlier paper. From star counts, we obtain a density profile, with a power-law cusp of slope -0.84 ± 0.16. No flat core is evident. We construct color-magnitude diagrams down to the main-sequence turnoff near the cluster center, and more than three magnitudes below the turnoff in the outermost field at r=28". The former diagram reveals a central population of blue stragglers, which has not previously been observed in this cluster. These blue stragglers are quite similar in specific frequency to those recently observed by HST in the core of 47 Tuc, and their presence adds to the growing evidence of stellar interactions in dense globular-cluster cores. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 74 618 Photometry of all stars brighter than V=20 in our inner two fields in NGC 6624 table2.dat 57 166 Photometry of all stars brighter than V=23 in our outermost FOC field in NGC 6624
Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 4 I4 --- ID Identification number 5- 7 I3 --- Field *[1,2] Field number 8- 14 F7.1 pix Xpos X coordinate on F480LP image under Field 15- 21 F7.1 pix Ypos Y coordinate on F480LP image under Field 22- 28 F7.3 arcsec oRA *RA (J2000) relative to cluster center 29- 35 F7.3 arcsec oDE *Dec (J2000) relative to cluster center 36- 42 F7.2 mag m480 F480LP instrumental magnitude 43- 48 F6.2 mag m430-m480 F430W - F480LP color (HST instr. system) 49- 55 F7.2 mag Vmag V magnitude 56- 61 F6.2 mag B-V B-V color 64- 74 A11 --- Comment Comments
Note on Field: 1=central 11x11 arcsec image, 2=image at r=10"Note on oRA, oDE: Note on oRA, oDE: Coordinates of cluster center: B1950 RA 18h 20m 27.686s ± 0.021s Dec -30d 23' 17.10" ± 0.27" J2000 RA 18h 23m 40.453s ± 0.021s Dec -30d 21' 40.75" ± 0.27"-------------------------------------------------------------------------------- Byte-by-byte Description of file: table2.dat
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 4 I4 --- ID Identification number 6- 11 F6.1 pix Xpos X coord. on outermost (r=28") F480LP image 12- 17 F6.1 pix Ypos Y coord. on outermost (r=28") F480LP image 18- 24 F7.3 arcsec oRA *RA (J2000) relative to star at (257,286) 25- 31 F7.3 arcsec oDE *Dec (J2000) relative to star at (257,286) 32- 38 F7.2 mag m480 F480LP instrumental magnitude 39- 44 F6.2 mag m430-m480 F430W - F480LP color (HST instr. system) 45- 51 F7.2 mag Vmag V magnitude 52- 57 F6.2 mag B-V B-V color
Note on oRA, oDE: Coordinates of bright star at (257,286) in outermost field: B1950 RA 18h 20m 29.141s ± 0.012s Dec -30d 22' 54.91" ± 0.15" J2000 RA 18h 23m 41.898s ± 0.012s Dec -30d 21' 18.45" ± 0.15"-------------------------------------------------------------------------------- Origin: AAS CD-ROM series, Volume 4, 1995 Lee Brotzman [ADS] 25-Apr-1995
Origin: AAS CD-ROM series, Volume 4, 1995 Lee Brotzman [ADS] 25-Apr-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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