Wide-field imaging of NGC 4365's globular cluster system: The third subpopulation revisited

摘要: Analysis of the globular cluster (GC) system giant elliptical (E3) galaxy NGC 4365, from eight Hubble Space Telescope/Advanced Camera for Surveys pointings and a wide-field Subaru/Suprime-Cam image, is presented. Using magnitude, colour size criteria, we obtain catalogue GC candidates. We also measure photometric properties starlight, including new effective radius. determine lower limit on number GCs to be  and show that extends beyond 134 kpc (9.5 radii). revisit question whether 4365 has bimodal or trimodal distribution find support three distinct subpopulations (i.e. blue, green red). Sersic profile fits radial surface density each subpopulation reveal blue are more extended than either red GCs. The median half-light radii in are ,  and  pc, respectively. estimated ellipticities are ,  and  for GCs, respectively, where alignment with position angle () assumed. A Kolmogorov–Smirnov test mass functions shows a 98 per cent probability all one another. gradients (metallicity) tilt. properties, profile, angle, ellipticity gradient, very similar 4365’s starlight. This result supports hypothesis formed along bulk diffuse starlight galaxy. kinematically core significant misalignment between kinematic major-axes. discuss possibility these features related presence third subpopulation. briefly implications formation finding major-merger, multiphase-collapse accretion scenarios could account existence