CDROM/AJ/V108/P2087 Globular Clusters in Ellipticals (Ajhar+ 1994) ================================================================================ VRI Photometry of Globular Clusters in Virgo and Leo Ellipticals Edward A. Ajhar, John P. Blakeslee and John L. Tonry <1994, AJ, 108, 2087> =1994AJ....108.2087A ================================================================================ Abstract: We present VRI photometry for the globular cluster systems (GCS's) of ten elliptical and S0 galaxies in Virgo and Leo. We find that the V-I color (metallicity) distributions are quite different from galaxy to galaxy. One extreme is represented by NGC 4374 with a narrow, blue distribution. NGC 4472 has a very broad, uniform distribution in color, corresponding to -1.8 < [Fe/H] < +0.47. At the other extreme is NGC 4365, which is weighted towards red colors, and possibly has a peculiar luminosity function. We suggest that this variation of GCS metallicity depends on environment, with formation of high metallicity globular clusters inhibited in higher density environments. We compare color-color plots of the GCS's of these galaxies with the Milky Way GCS and with integrated isochrones. We find good agreement with the galaxies studied here except that the isochrones predict colors which are slightly too bright in the I band for metal-rich clusters. We also consider the radial GC color distributions in these galaxies. We find evidence for a V-I color gradient only in NGC 4374, in the sense of redder clusters toward the center of the galaxy but warn that possible systematic effects must be ruled out with the new data. Lastly, using the surface brightness fluctuation distances to these galaxies, we find supporting evidence for the universality of the globular cluster luminosity function. Description: Tables 3-12 contain the positions, radial distances, magnitudes, and colors of objects located for each galaxy. Only objects brighter than R=22 and classified by DOPHOT as point sources in the V, R, and I images are included in the tables. The positions are in arcseconds and are relative to the center of the galaxy such that +x is to the west and +y is to the north. The magnitude and colors of each object have been corrected for reddening and absorption according to Equation (1) of the paper and following the values listed in Table 2 of the paper. Please use those values to recover the actual apparent magnitudes of these objects if desired. File Summary: -------------------------------------------------------------------------------- File Name Lrecl Records Explanations -------------------------------------------------------------------------------- table3.dat 41 60 NGC 3379 table4.dat 41 142 NGC 4365 table5.dat 41 119 NGC 4374 table6.dat 41 105 NGC 4406 table7.dat 41 29 NGC 4458 table8.dat 41 21 NGC 4468 table9.dat 41 170 NGC 4472 table10.dat 41 16 NGC 4489 table11.dat 41 127 NGC 4552 table12.dat 41 26 NGC 4578 -------------------------------------------------------------------------------- Byte-by-byte Description of file: table3.dat table4.dat table5.dat table6.dat table7.dat table8.dat table9.dat table10.dat table11.dat table12.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 3 I3 --- ID Identification number 4-10 F7.1 arcsec X X position relative to center of galaxy 11-17 F7.1 arcsec Y Y position relative to center of galaxy 18-23 F6.1 arcsec Dist Radial distance 24-29 F6.2 mag R R magnitude 30-35 F6.3 mag V-R V-R color 36-41 F6.3 mag R-I R-I color -------------------------------------------------------------------------------- ================================================================================ (End) Lee Brotzman [ADS] 24-Apr-1995