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J/AJ/122/2458       M31 globular clusters from HST           (Barmby+, 2001)

M31 globular clusters in the Hubble Space Telescope archive. I. Cluster detection and completeness. Barmby P., Huchra J.P. <Astron. J. 122, 2458 (2001)> =2001AJ....122.2458B
ADC_Keywords: Clusters, globular Keywords: galaxies: individual (M31) - galaxies: star clusters Abstract: Globular clusters at the distance of M31 have apparent angular sizes of a few arcseconds. While many M31 globular clusters have been detected and studied from ground-based images, the high spatial resolution of the Hubble Space Telescope (HST) allows much more robust detection and characterization of star cluster properties. We present the results of a search of 157 HST Wide Field Planetary Camera 2 images of M31. We found 82 previously catalogued globular cluster candidates, as well as 32 new globular cluster candidates and 20 open cluster candidates. We present images of the new candidates and photometry for all clusters. We assess existing cluster catalogs' completeness and use the results to estimate the total number of globular clusters in M31 as 460±70. The specific frequency is SN=1.2±0.2 and the mass specific frequency T=2.4±0.4; these values are at the upper end of the range seen for spiral galaxies. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 45 154 HST fields Used in the search table2.dat 62 68 Catalogued objects that are not M31 globular clusters table3.dat 76 52 New globular cluster candidates found in M31 HST fields table4.dat 62 129 Photometry of new clusters and candidates in M31
See also: J/A+AS/116/447 : M31 globulars clusters ellipticities (Staneva+, 1996) J/AJ/114/1488 : Globulars in M31 (Holland+ 1997) J/AcA/48/455 : Globular Clusters in M31 and M33 (Mochejska+, 1998) J/AJ/119/727 : M31 globular clusters photometry (Barmby+, 2000) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 2 I2 h RAh Hour of Right Ascension (J2000) 4- 5 I2 min RAm Minute of Right Ascension (J2000) 7- 11 F5.2 s RAs Second of Right Ascension (J2000) 13 A1 --- DE- Sign of the Declination (J2000) 14- 15 I2 deg DEd Degree of Declination (J2000) 17- 18 I2 arcmin DEm Arcminute of Declination (J2000) 20- 23 F4.1 arcsec DEs Arcsecond of Declination (J2000) 25- 29 A5 --- Filt Filter used in observation 31- 34 I4 s Exp Combined exposure of all images 36- 44 A9 --- Name Dataset name
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 9 A9 --- Name Catalog object name, as in Barmby et al., 2000, Cat. J/AJ/119/727 11- 21 A11 --- Class Object classification (1) 23- 61 A39 --- HST The HST field(s) image name(s)
Note (1): Object classification: pr: Objects which have slightly larger FWHMs than most stars, although we still believe them to be stars. stars: Objects which appear to be blended images of 2 or 3 stars. blank: Object which was not detected at its catalog coordinates.
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 20 A20 --- Name Cluster designation, M31GC JHHMMSS+DDMMSS or M31OC JHHMMSS+DDMMSS 22- 23 I2 h RAh Right ascension (J2000) 25- 26 I2 min RAm Right ascension (J2000) 28- 32 F5.2 s RAs Right ascension (J2000) 34 A1 --- DE- Declination sign (J2000) 35- 36 I2 deg DEd Declination (J2000) 38- 39 I2 arcmin DEm Declination (J2000) 41- 44 F4.1 arcsec DEs Declination (J2000) 46- 48 A3 --- Qual [ABCD/ ] Globular cluster probability code (1) 51- 76 A26 --- Com Comments and possible identification
Note (1): Probability of globular cluster nature: A, B: High-probability globular cluster candidates (A: very likely to be a globular cluster) C, D: Low-probability globular cluster candidates (D: likely not a globular cluster)
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 20 A20 --- Name Cluster name (1) 22- 27 F6.3 mag Umag ? The integrated U band magnitude 28 A1 --- f_Umag [*] Indicates a F300W instead of standard U-band magnitude 30- 35 F6.3 mag Bmag ? The integrated B band magnitude 37- 42 F6.3 mag Vmag ? The integrated V band magnitude 44- 49 F6.3 mag Rmag ? The integrated R band magnitude 51- 56 F6.3 mag Imag ? The integrated I band magnitude 58- 61 F4.2 arcsec Rad1/2 The half-light radius
Note (1): Names: [BHB2000] NNNNNN: Name as in Barmby et al., 2000, Cat. J/AJ/119/727 Nbol NN: Name as in Barmby et al., 2000, Cat. J/AJ/119/727 M31GC JHHMMSS+DDMMSS or M31OC JHHMMSS+DDMMSS: Name from table3.dat
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 22-Jan-2002
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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