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J/A+A/606/A21       LMC bar star clusters                        (Piatti, 2017)

The real population of star clusters in the bar of the Large Magellanic Cloud. Piatti A.E. <Astron. Astrophys. 606, A21 (2017)> =2017A&A...606A..21P (SIMBAD/NED BibCode)
ADC_Keywords: Magellanic Clouds ; Associations, stellar ; Photometry, CMT1T2V Keywords: techniques: photometric - galaxies: individual: LMC - Magellanic Clouds Abstract: We report results on star clusters located in the South-Eastern half of the Large Magellanic (LMC) bar fromWashington CT1 photometry. Using appropriate kernel density estimators we detected 73 star cluster candidates, three of which do not show any detectable trace of star cluster sequences in their colour-magnitude diagrams (CMDs).We did not detect other 38 previously catalogued clusters, which could not be recognized when visually inspecting the C and T1 images either; the distribution of stars in their respective fields do not resemble that of an stellar aggregate. They represent ∼33 per cent of all catalogued objects located within the analysed LMC bar field. From matching theoretical isochrones to the cluster CMDs cleaned from field star contamination, we derived ages in the range 7.2<log(t[yr-1])<10.1. As far as we are aware, this is the first time homogeneous age estimates based on resolved stellar photometry are obtained for most of the studied clusters. We built the cluster frequency (CF) for the surveyed area, and found that the major star cluster formation activity has taken place during the period log(t[yr-1])∼8.0-9.0. Since ∼100Myr ago, clusters have been formed during few bursting formation episodes. When comparing the observed CF to that recovered from the star formation rate we found noticeable differences, which suggests that field star and star cluster formation histories could have been significantly different. Description: Magnitudes and colours of stars in the field of 70 clusters whose name are used as rootname of each file (e.g. ngc1969.dat corresponds to data for NGC 1969). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 55 70 Fundamental properties of the star cluster sample clusters.dat 82 83013 Magnitudes and colours of stars of the 70 clusters files/* 74 70 Individual cluster magnitudes and colours of stars
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 13 A13 --- Name Cluster name 15- 18 F4.2 mag E(V-I) V-I colour excess 19 A1 --- n_E(V-I) [)] Note on E(V-I) (1) 21- 25 F5.2 [yr-1] logt Age 27- 30 I4 --- Nstar Number of stars in the cluster 32- 40 A9 --- Cluster Cluster shorted name (as in clusters.dat file) 44- 55 A12 --- FileName Name of the individual cluster file in subdirectory files
Note (1): ) indicates E(V-I) values slightly larger than those from Haschke et al. (2011AJ....141..158H) to get a better isochrone matching. Nevertheless they are within the dispersion given for the OGLE III E(V-I) colour excesses.
Byte-by-byte Description of file: clusters.dat
Bytes Format Units Label Explanations
1- 9 A9 --- Cluster Cluster shorted name 11- 15 I5 --- ID Star number within the cluster 18- 19 I2 h RAh Right ascension (J2000) 21- 22 I2 min RAm Right ascension (J2000) 24- 29 F6.3 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- 42 F5.2 arcsec DEs Declination (J2000) 45- 51 F7.4 mag Cmag ?=99.9999 C magnitude 55- 60 F6.4 mag e_Cmag ?=9.9999 rms uncertainty on Cmag 63- 69 F7.4 mag T1mag ?=99.9999 T1 magnitude 73- 78 F6.4 mag e_T1mag ?=9.9999 rms uncertainty on T1mag 82 I1 --- Memb [1/4] Membership probability code (G1)
Byte-by-byte Description of file: files/*
Bytes Format Units Label Explanations
1- 7 I7 --- ID Star number within the cluster 10- 11 I2 h RAh Right ascension (J2000) 12 A1 --- --- [:] 13- 14 I2 min RAm Right ascension (J2000) 15 A1 --- --- [:] 16- 21 F6.3 s RAs Right ascension (J2000) 23 A1 --- DE- Declination sign (J2000) 24- 25 I2 deg DEd Declination (J2000) 26 A1 --- --- [:] 27- 28 I2 arcmin DEm Declination (J2000) 29 A1 --- --- [:] 30- 34 F5.2 arcsec DEs Declination (J2000) 37- 43 F7.4 mag Cmag ?=99.9999 C magnitude 47- 52 F6.4 mag e_Cmag ?=9.9999 rms uncertainty on Cmag 55- 61 F7.4 mag T1mag ?=99.9999 T1 magnitude 65- 70 F6.4 mag e_T1mag ?=9.9999 rms uncertainty on T1mag 74 I1 --- Memb [1/4] Membership probability code (G1)
Global notes: Note (G1): Membership probability code as follows: 1 = 25% 2 = 50% 3 = 75% 4 = 100%
Acknowledgements: Andres Piatti, andres(at)oac.unc.edu.ar
(End) Patricia Vannier [CDS] 25-Jul-2017
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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