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J/MNRAS/374/399     Infrared star clusters with |b|<20°  (Froebrich+, 2007)

A systematic survey for infrared star clusters with |b|<20° using 2MASS. Froebrich D., Scholz A., Raftery C.L. <Mon. Not. R. Astron. Soc., 374, 399-408 (2007)> =2007MNRAS.374..399F
ADC_Keywords: Clusters, globular ; Clusters, open ; Infrared sources Keywords: methods: statistical - globular clusters: general - open clusters and associations: general Abstract: We used star density maps obtained from the Two-Micron All-Sky Survey (2MASS) to obtain a sample of star clusters in the entire Galactic Plane with |b|<20°. A total of 1788 star cluster candidates are identified in this survey. Among those are 681 previously known open clusters and 86 globular clusters. A statistical analysis indicates that our sample of 1021 new cluster candidates has a contamination of about 50 per cent. Star cluster parameters are obtained by fitting a King profile to the star density. These parameters are used to statistically identify probable new globular cluster candidates in our sample. A detailed investigation of the projected distribution of star clusters in the Galaxy demonstrates that they show a clear tendency to cluster on spatial scales in the order of 12-25pc, a typical size for molecular clouds. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file tablea1.dat 118 473 Properties of the probable clusters in our sample of newly detected star cluster candidates tableb1.dat 118 548 Properties of the possible clusters in our sample of newly detected star cluster candidates
See also: II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003) Byte-by-byte Description of file: tablea1.dat tableb1.dat
Bytes Format Units Label Explanations
1- 4 I4 --- FSR [1/1767] Sequential number, <[FSR2007] NNNN> in Simbad 6- 12 F7.3 deg GLON Galactic longitude 14- 20 F7.3 deg GLAT Galactic latitude 22- 23 I2 h RAh Right ascension (J2000) 25- 26 I2 min RAm Right ascension (J2000) 28- 29 I2 s RAs Right ascension (J2000) 31 A1 --- DE- Declination sign (J2000) 32- 33 I2 deg DEd Declination (J2000) 35- 36 I2 arcmin DEm Declination (J2000) 38- 39 I2 arcsec DEs Declination (J2000) 41- 45 F5.3 deg rcore Core radius as fitted to the H-band radial star density profile 47- 51 F5.3 deg rtid Tidal radius as fitted to the H-band radial star density profile 53- 54 I2 arcmin-2 Dc Central star density in stars/arcmin2 as fitted to H-band radial star density profile 56- 58 I3 --- Dcont ?=-99 Star density contrast in the H band (1) 60- 64 I5 --- N Number of stars in the cluster as obtained using eq. (3) and the star density profile in the H band 66- 70 I5 --- Nc Corrected number of stars in the cluster determined using eq. (4) at an apparent magnitude of 15 in the H band 72- 77 F6.3 --- logRN ?=99.0 Measure logRN as determined in Sect. 4.4 (2) 79 I1 --- Q [0,6] Quality flag determined from our analysis of the radial density profile fit (3) 81- 86 I06 --- Qall Detailed quality flags (3) 88-118 A31 --- Ident Name of possible known cluster with erroneous coordinates in SIMBAD
Note (1): determined as ratio of the central star density and the square root of the background star density. Values of 99 indicate objects with a fitted background star density of zero. Note (2): RN=(POp/PGl)/(681/86), where POp is the Open cluster probability and PGl the globular cluster probability. If logRN is negative, the object is probably a globular cluster, otherwise it is an open cluster. Values of 99.0 indicate cluster candidates with PGl=0. Note (3): the details are in Sect. 4.2 of the paper. Q contains the number of negative tests (i.e. digits set to 1) in Qall. Qall is a 6-digit binary number identifying which of the quality tests are negative: #1 = the cluster is detected automatically (0) or manually (1); #2 = the scatter of the three fitted core radii is larger than 30% (1) or smaller (0); #3 = the scatter of the three fitted tidal radii is larger than 66% (1) or smaller (0); #4 = the contrast of the central to background star density [Ic/sqrt(Ibg)] in all filters is larger than five (0) or not (1); #5 = the ratio of tidal to core radius in all three filters is between 3 and 45 (0) or not (1); #6 = the core radius in all three filters is larger than twice the error of the coordinates, i.e. 0.01° (0) or not (1).
Acknowledgements: Dirk Froebrich, df(at)
(End) Patricia Vannier [CDS] 28-Aug-2007
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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