J/ApJS/166/249 Stellar dynamics and proper motions in 47Tuc (McLaughlin+, 2006)
Hubble Space Telescope proper motions and stellar dynamics in the core of the
globular cluster 47 Tucanae.
McLaughlin D.E., Anderson J., Meylan G., Gebhardt K., Pryor C., Minniti D.,
Phinney S.
<Astrophys. J. Suppl. Ser., 166, 249-297 (2006)>
=2006ApJS..166..249M 2006ApJS..166..249M
ADC_Keywords: Clusters, globular ; Photometry ; Positional data ; Proper motions
Keywords: astrometry - globular clusters: individual (NGC 104) -
stellar dynamics
Abstract:
We have used HST imaging of the central regions of the globular
cluster 47 Tucanae (=NGC 104), taken with the WFPC2 and ACS
instruments between 1995 and 2002, to derive proper motions and U- and
V-band magnitudes for 14366 stars within 100 (about 5 core radii) of
the cluster center. This represents the largest set of member
velocities collected for any globular cluster. The stars involved
range in brightness from just fainter than the horizontal branch of
the cluster to more than 2.5mag below the main-sequence turnoff. In
the course of obtaining these kinematic data, we also use a recent set
of ACS images to define a list of astrometrically calibrated positions
(and F475W magnitudes) for nearly 130000 stars in a larger, 3x3
central area. We describe our data reduction procedures in some detail
and provide the full position, photometric, and velocity data.
Description:
This project began with a series of WFPC2 exposures of the center of
47 Tuc in 1995, 1997, and 1999 (programs GO-5912, GO-6467, and
GO-7503, PI: G. Meylan). Additional WFPC2 images of the same central
field as the Meylan pointings were obtained in 1999 and 2001 (GO-8267
and GO-9266, PI: R. Gilliland) through the similarly short-wavelength
filter F336W.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 79 8 Stars used for astrometric calibration, and the
resulting cluster center point/star
table4.dat 126 129733 129733 stars in the Master Frame
table5a.dat 132 14366 Proper motions data for 14366 stars
table5b.dat 407 14366 Displacement data for 14366 stars
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See also:
J/A+AS/93/293 : Astrometry of globular clusters (47 Tuc) (Tucholke 1992)
J/ApJS/85/293 : HST Observations of core of 47 Tuc (de Marchi+ 1993)
J/A+A/391/945 : HST photometry of 74 galactic globular clusters (Piotto+, 2002)
J/ApJ/625/796 : X-ray sources in the globular cluster 47 Tuc (Heinke+, 2005)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- AName Name of object on Fig. 3
9 A1 --- --- [M] Master frame
10- 15 I06 --- Name ? Sequential star number
17- 20 F4.1 mag F475W ? HST/ACS F475W VEGAMAG system magnitude
22- 25 I4 pix xraw Raw X position in the top chip (WFC1) of the
j8cd01a9q_flt frame from program GO-9028
27- 29 I3 pix yraw Raw Y position in the top chip (WFC1) of the
j8cd01a9q_flt frame from program GO-9028
31- 37 F7.3 arcsec oRA Right ascension offset from center (G1)
39- 44 F6.3 arcsec oDE Declination offset from center (G1)
46- 47 I2 h RAh Hour of right ascension (J2000)
49- 50 I2 min RAm Minute of right ascension (J2000)
52- 56 F5.2 s RAs Second of right ascension (J2000)
58- 61 F4.2 s e_RAs Error on right ascension (J2000)
63 A1 --- DE- Sign of the declination (J2000)
64- 65 I2 deg DEd Degree of declination (J2000)
67- 68 I2 arcmin DEm Arcminute of declination (J2000)
70- 74 F5.2 arcsec DEs Arcsecond of declination (J2000)
76- 79 F4.2 arcsec e_DEs Error on declination (J2000)
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 8 F8.4 arcsec oRA Right ascension offset from center (G1)
10- 18 F9.4 arcsec oDE Declination offset from center (G1)
20- 24 F5.2 mag F475W ?=99.99 HST/ACS F475W VEGAMAG magnitude
26- 34 F9.7 h RAhr Right ascension (J2000, Ep=2002.26)
36- 45 F10.6 deg DEdeg Declination (J2000, Ep=2002.26)
47- 48 I2 h RAh Hour of right ascension (J2000, Ep=2002.26)
50- 51 I2 min RAm Minute of right ascension (J2000, Ep=2002.26)
53- 58 F6.3 s RAs Second of right ascension (J2000, Ep=2002.26)
60 A1 --- DE- Sign of the declination (J2000, Ep=2002.26)
61- 62 I2 deg DEd Degree of declination (J2000, Ep=2002.26)
64- 65 I2 arcmin DEm Arcminute of declination (J2000, Ep=2002.26)
67- 71 F5.2 arcsec DEs Arcsecond of declination (J2000, Ep=2002.26)
73- 77 F5.2 mag min Faintest star that could be included
in the neighbourhood as "OK" (2)
79 I1 --- OK Star OK? (3)
81- 86 F6.2 % c Local completeness fraction (4)
88 A1 --- --- [M] Master frame
89- 94 I06 --- Name Sequential star number (NNNNNN),
Cl* NGC 104 MAM MNNNNNN in Simbad
96-102 F7.2 pix Xpix47 X location in the meta image, 47TucMaster.fits
104-110 F7.2 pix Ypix47 Y location in the meta image, 47TucMaster.fits
112-118 F7.2 pix Xpixrf X location in the ref. image, j8cd01a9q_w.fits
120-126 F7.2 pix Ypixrf Y location in the ref. image, j8cd01a9q_w.fits
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Note (2): This number comes from an analysis of the star's nearby
neighbors; see section 2.2.5 of the paper.
Note (3): OK flag is:
0 = Star is likely a PSF artifact and should not be trusted
1 = Bona fide stellar detection
Note (4): Of the local neighborhood, r<100 WFC pixels, or 5". Corresponds
to a completeness-corrected total "number" of (100/c) stars at the
given position and magnitude in the master frame (GO-9028, Ep=2002.26).
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Byte-by-byte Description of file: table5a.dat
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Bytes Format Units Label Explanations
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1 A1 --- --- [M] Master frame
2- 7 I06 --- Name Sequential star number
9- 16 F8.4 arcsec Xpos Offset in RA from cluster center
18- 25 F8.4 arcsec Ypos Offset in DE from cluster center
27- 32 F6.3 mag Vmag Calibrated V magnitude
34- 39 F6.3 mag Umag Calibrated U magnitude
41- 45 F5.2 mag F475W Calibrated HST/ACS F475W magnitude
47- 55 F9.7 h RAhr Right ascension (J2000, Ep=2002.26) (1)
57- 66 F10.6 deg DEdeg Declination (J2000, Ep=2002.26) (1)
68- 76 E9.4 arcsec/yr pmRA Weighted least-squares proper motion along RA
78- 85 E8.4 arcsec/yr e_pmRA rms uncertainty on pmRA
87- 92 F6.3 --- chi2RA chi-square of the weighted least-squares
fit to Xpos vs time
94- 99 F6.4 --- P(chi2RA) Probability for chi2RA (2)
101-109 E9.4 arcsec/yr pmDE Weighted least-squares proper motion along DE
111-118 E8.4 arcsec/yr e_pmDE rms uncertainty on pmDE
120-125 F6.3 --- chi2DE chi-square of the weighted least-squares
fit to Ypos vs time
127-132 F6.4 --- P(chi2DE) Probability for chi2DE (2)
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Note (1): measured in master frame at date Ep=2002.26
Note (2): probability that this chi-square value or higher could occur by
chance if the true RA/DE motion follows a straight line (lower P is
worse).
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Byte-by-byte Description of file: table5b.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- --- [M] Master frame
2- 7 I06 --- Name Sequential star number
9- 17 E9.4 arcsec X1pos ?=- RA displacements of the star from nominal
position for dataset MEYLANe1 (1995.82)
19- 27 E9.4 arcsec e_X1pos ?=- rms uncertainty on X1pos
29- 37 E9.4 arcsec X2pos ?=- RA displacements of the star from nominal
position for dataset MEYLANe2 (1997.84)
39- 47 E9.4 arcsec e_X2pos ?=- rms uncertainty on X2pos
49- 57 E9.4 arcsec X3pos ?=- RA displacements of the star from nominal
position for dataset GILLILU1 (1999.51)
59- 67 E9.4 arcsec e_X3pos ?=- rms uncertainty on X3pos
69- 77 E9.4 arcsec X4pos ?=- RA displacements of the star from nominal
position for dataset MEYLANe3 (1999.82)
79- 87 E9.4 arcsec e_X4pos ?=- rms uncertainty on X4pos
89- 97 E9.4 arcsec X5pos ?=- RA displacements of the star from nominal
position for dataset GILLILU2 (2001.53)
99-107 E9.4 arcsec e_X5pos ?=- rms uncertainty on X5pos
109-117 E9.4 arcsec X6pos ?=- RA displacements of the star from nominal
position for dataset WFC-MEUR (2002.26)
119-127 E9.4 arcsec e_X6pos ?=- rms uncertainty on X6pos
129-137 E9.4 arcsec X7pos ?=- RA displacements of the star from nominal
position for dataset HRC-MEUR (2002.26)
139-147 E9.4 arcsec e_X7pos ?=- rms uncertainty on X7pos
149-157 E9.4 arcsec X8pos ?=- RA displacements of the star from nominal
position for dataset WFC-BOHL (2002.28)
159-167 E9.4 arcsec e_X8pos ?=- rms uncertainty on X8pos
169-177 E9.4 arcsec X9pos ?=- RA displacements of the star from nominal
position for dataset WFC-KING (2002.52)
179-187 E9.4 arcsec e_X9pos ?=- rms uncertainty on X9pos
189-197 E9.4 arcsec X10pos ?=- RA displacements of the star from nominal
position for dataset HRC-KING (2002.56)
199-207 E9.4 arcsec e_X10pos ?=- rms uncertainty on X10pos
209-217 E9.4 arcsec Y1pos ?=- DE displacements of the star from nominal
position for dataset MEYLANe1 (1995.82)
219-227 E9.4 arcsec e_Y1pos ?=- rms uncertainty on Y1pos
229-237 E9.4 arcsec Y2pos ?=- DE displacements of the star from nominal
position for dataset MEYLANe2 (1997.84)
239-247 E9.4 arcsec e_Y2pos ?=- rms uncertainty on Y2pos
249-257 E9.4 arcsec Y3pos ?=- DE displacements of the star from nominal
position for dataset GILLILU1 (1999.51)
259-267 E9.4 arcsec e_Y3pos ?=- rms uncertainty on Y3pos
269-277 E9.4 arcsec Y4pos ?=- DE displacements of the star from nominal
position for dataset MEYLANe3 (1999.82)
279-287 E9.4 arcsec e_Y4pos ?=- rms uncertainty on Y4pos
289-297 E9.4 arcsec Y5pos ?=- DE displacements of the star from nominal
position for dataset GILLILU2 (2001.53)
299-307 E9.4 arcsec e_Y5pos ?=- rms uncertainty on Y5pos
309-317 E9.4 arcsec Y6pos ?=- DE displacements of the star from nominal
position for dataset WFC-MEUR (2002.26)
319-327 E9.4 arcsec e_Y6pos ?=- rms uncertainty on Y6pos
329-337 E9.4 arcsec Y7pos ?=- DE displacements of the star from nominal
position for dataset HRC-MEUR (2002.26)
339-347 E9.4 arcsec e_Y7pos ?=- rms uncertainty on Y7pos
349-357 E9.4 arcsec Y8pos ?=- DE displacements of the star from nominal
position for dataset WFC-BOHL (2002.28)
359-367 E9.4 arcsec e_Y8pos ?=- rms uncertainty on Y8pos
369-377 E9.4 arcsec Y9pos ?=- DE displacements of the star from nominal
position for dataset WFC-KING (2002.52)
379-387 E9.4 arcsec e_Y9pos ?=- rms uncertainty on Y9pos
389-397 E9.4 arcsec Y10pos ?=- DE displacements of the star from nominal
position for dataset HRC-KING (2002.56)
399-407 E9.4 arcsec e_Y10pos ?=- rms uncertainty on Y10pos
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Global notes:
Note (G1): RA and DE offsets (positive eastward and northward,
respectively) from the cluster center in the master-frame system,
00:24:05.67-72:04:52 (J2000), measured at date 2002.26 from ACS
images taken as part of program GO-9028.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 16-May-2008