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J/A+A/435/65   UBVI photometry of NGC 6872 clusters population  (Bastian+, 2005)

The star cluster population in the tidal tails of NGC 6872. Bastian N., Hempel H., Kissler-Patig M., Homeier N., Trancho G. <Astron. Astrophys. 435, 65 (2005)> =2005A&A...435...65B
ADC_Keywords: Associations, stellar ; Photometry, UBVRI Keywords: galaxies: star clusters - galaxies: interactions - galaxy: individual: NGC 6872 Abstract: We present a photometric analysis of the rich star cluster population in the tidal tails of NGC 6872. We find star clusters with ages between 1-100Myr distributed in the tidal tails, while the tails themselves have an age of less than 150Myr. Most of the young massive (104≤M/M_☉≤107) clusters are found in the outer regions of the galactic disk or the tidal tails. The mass distribution of the cluster population can be well described by a power-law of the form N(m)∝m-alpha, where alpha=1.85±0.11, in very good agreement with other young cluster populations found in a variety of different environments. We estimate the star formation rate for three separate regions of the galaxy, and find that the eastern tail is forming stars at ∼2 times the rate of the western tail and ∼5 times the rate of the main body of the galaxy. By comparing our observations with published N-body models of the fate of material in tidal tails in a galaxy cluster potential, we see that many of these young clusters will be lost into the intergalactic medium. We speculate that this mechanism may also be at work in larger galaxy clusters such as Fornax, and suggest that the so-called ultra-compact dwarf galaxies could be the most massive star clusters that have formed in the tidal tails of an ancient galactic merger. Description: Photometric and derived properties for the star cluster candidates in the interacting galaxy NGC 6872. The table provides the ID, position, photometry and errors, the reduced chi-squared of the best fitting model, the extinction, age, and mass of the best fitting model, and the absolute magnitude of the source correcting for the distance and reddening. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 118 118 Cluster positions, magnitudes and derived properties
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 3 I3 --- Seq Sequential number of the cluster candidate 5- 6 I2 h RAh Right ascension (J2000.0) 8- 9 I2 min RAm Right ascension (J2000.0) 11- 16 F6.3 s RAs Right ascension (J2000.0) 18 A1 --- DE- Declination sign (J2000.0) 19- 20 I2 deg DEd Declination (J2000.0) 22- 23 I2 arcmin DEm Declination (J2000.0) 25- 29 F5.2 arcsec DEs Declination (J2000.0) 31- 36 F6.1 pix Xpos X position of the source (1) 38- 43 F6.1 pix Ypos Y position of the source (1) 45- 49 F5.2 mag Umag U magnitude of the source(2) 51- 54 F4.2 mag e_Umag Error in the U mag 56- 60 F5.2 mag Bmag B magnitude of the source(2) 62- 65 F4.2 mag e_Bmag Error in the B mag 67- 71 F5.2 mag Vmag V magnitude of the source(2) 73- 76 F4.2 mag e_Vmag Error in the V mag 78- 82 F5.2 mag Icmag Cousins I magnitude of the source(2) 84- 87 F4.2 mag e_Icmag Error in the Ic mag 89- 92 F4.2 --- chi2 Reduced chi-squared of the best fitting model 94- 97 F4.2 mag AV Total V-band extinction of the source 99-103 F5.2 [yr] logAge Logarithmic best fitting age of the source 105-108 F4.2 [solMass] logMass Logarithmic best fitting mass of the source 110-115 F6.2 mag VMAG Absolute magnitude of the source (3)
Note (1): Pixel coordinates used in Figs. 6-8 of the paper Note (2): The magnitudes are only corrected for foreground extinction Note (3): Absolute magnitude corrected for the derived extinction
Acknowledgements: Nate Bastian, bastian(at)astro.uu.nl
(End) Nate Bastian [Utrecht, Netherlands], Patricia Vannier [CDS] 01-Mar-2005
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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