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J/A+A/483/769  HST VI photometry of 3 globulars in M31  (Fuentes-Carrera+, 2008)

Evidence for metallicity spreads in three massive M31 globular clusters. Fuentes-Carrera I., Jablonka P., Sarajedini A., Bridges T., Djorgovski G., Meylan G. <Astron. Astrophys. 483, 769 (2008)> =2008A&A...483..769F
ADC_Keywords: Galaxies, nearby ; Clusters, globular ; Photometry, HST Keywords: galaxies: evolution - galaxies: Local Group - galaxies: star clusters - Galaxy: globular clusters: general Abstract: We quantify the intrinsic width of the red giant branches of three massive globular clusters in M 31 in a search for metallicity spreads within these objects. We present HST/ACS observations of three massive clusters in M 31, G78, G213, and G280. A thorough description of the photometry extraction and calibration is presented. After derivation of the color-magnitude diagrams, we quantify the intrinsic width of the red giant branch of each cluster. Description: The Tables present the individual photometric measurements of stars in the field of view of the globular clusters G78 (table2a.dat), G213 (table2b.dat) and G280 (table2c.dat) in M31. Observations of the three clusters and their surrounding fields were done with the High Resolution Channel (HRC) of the Advanced Camera for Surveys (ACS) aboard HST. Four images of each globular cluster were taken using the F606W (close to V) and F814W (close to I) filters with total integration time of 505x4=2020s and 715x4=2860s, respectively. Images were dithered following the four-point dither pattern known as ACS-HRC-DITHER-BOX. The instrumental signature was removed from these images (bias, dark and flat-field correction) by the on-the-fly-reprocessing (OTFR) performed by CALACS. Images were corrected for geometric distortion and combined using the MultiDrizzle task of the STSci pipeline incorporated in PyRAF (Koekemoer et al., 2002, The 2002 HST Calibration Workshop, p.337 (2002hstc.conf..337K)). Photometry was extracted using the DAOPHOT/ALLSTAR routines (Stetson 1994PASP..106..250S). Point-spread functions (PSFs) were constructed with DAOPHOT and stars were measured using the ALLSTAR routine. A detailed description of the procedure is presented in the paper. In order to derive the color-magnitude diagrams (CMD) of each cluster, stars were statistically selected according to their photometric error, chi-square and sharpness values in order to get rid of spurious photometric detections that might contaminate the results. Remaining stars are indicated in the Tables with a "selection FLAG' value equal to 1. All values are in instrumental magnitudes. Objects: ------------------------------------------------------------------ RA (2000) DE Designation(s) (Table) ------------------------------------------------------------------ 00 41 01.3 +41 13 45 G78 = SKHB 78 = Bol 23 (table2a) 00 43 14.4 +41 07 21 G213 = SKHB 213 = Bol 158 (table2b) 00 44 29.6 +41 21 35 G280 = SKHB 280 = Bol 225 (table2c) ----------------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2a.dat 91 8805 Individual photometric measurements for stars in the field-of-view of globular cluster G78 in M31 table2b.dat 91 15233 Individual photometric measurements for stars in the field-of-view of globular cluster G213 in M31 table2c.dat 91 12982 Individual photometric measurements for stars in the field-of-view of globular cluster G280 in M31
Byte-by-byte Description of file: table2?.dat
Bytes Format Units Label Explanations
1- 5 I5 --- Seq Identification number (1) 7- 13 F7.2 pix Xpos Abscissa of star in the MultiDrizzled image (2) 15- 21 F7.2 pix Ypos Ordinate of star in the MultiDrizzled image (2) 23- 29 F7.4 mag F606 Instrumental magnitude in the F606W filter 31- 37 F7.5 mag e_F606 Photometric error in the F606W filter (3) 39- 46 F8.5 --- chi-F606 Chi-square value in the F606W filter (3) 48- 55 F8.5 --- sh-F606 Sharpness value in the F606W filter (3) 57- 63 F7.4 mag F814 Instrumental magnitude in the F814W filter 65- 71 F7.5 mag e_F814 Photometric error in the F814W filter (3) 73- 80 F8.5 --- chi-F814 Chi-square value in the F814W filter (3) 82- 89 F8.5 --- sh-F814 Sharpness value in the F814W filter (3) 91 I1 --- Flag [0/1] Selection flag (4)
Note (1): Identification number given by DAOPHOT for star identification Note (2): 1pix=0.027". Note (3): Values given by ALLSTAR (Stetson, 1994PASP..106..250S) Note (4): 1 indicates that the star survived the statistical selection discussed in the paper, and 0 that the star was rejected for the analysis of the CMD.
Acknowledgements: Isaura Fuentes-Carrera, isaura.fuentes(at)obspm.fr
(End) Patricia Vannier [CDS] 27-Mar-2008
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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