English

A WFC3 study of globular clusters in NGC 4150 - an early-type minor merger

Cosmology and Nongalactic Astrophysics 2015-05-28 v1 Instrumentation and Methods for Astrophysics

Abstract

We combine near-ultraviolet (NUV; 2250 {\AA}) and optical (U, B, V, I) imaging from the Wide Field Camera 3 (WFC3), on board the Hubble Space Telescope (HST), to study the globular cluster (GC) population in NGC 4150, a sub-L* (M_B ~ -18.48 mag) early-type minor-merger remnant in the Coma I cloud. We use broadband NUV-optical photometry from the WFC3 to estimate individual ages, metallicities, masses and line-of-sight extinctions [E_(B-V)] for 63 bright (M_V < -5 mag) GCs in this galaxy. In addition to a small GC population with ages greater than 10 Gyr, we find a dominant population of clusters with ages centred around 6 Gyr, consistent with the expected peak of stellar mass assembly in faint early-types residing in low-density environments. The old and intermediate-age GCs in NGC 4150 are metal-poor, with metallicities less than 0.1 ZSun, and reside in regions of low extinction (E_(B-V) < 0.05 mag). We also find a population of young, metal-rich (Z > 0.3 ZSun) clusters that have formed within the last Gyr and reside in relatively dusty (E_(B-V) > 0.3 mag) regions that are coincident with the part of the galaxy core that hosts significant recent star formation. Cluster disruption models (in which ~80-90% of objects younger than a few 10^8 yr dissolve every dex in time) suggest that the bulk of these young clusters are a transient population.

Keywords

Cite

@article{arxiv.1107.5042,
  title  = {A WFC3 study of globular clusters in NGC 4150 - an early-type minor merger},
  author = {Sugata Kaviraj and R. Mark Crockett and Bradley C. Whitmore and Joseph Silk and Robert W. O'Connell and Rogier A. Windhorst and Max Mutchler and Marina Rejkuba and Sukyoung Yi and Jay A. Frogel and Daniela Calzetti},
  journal= {arXiv preprint arXiv:1107.5042},
  year   = {2015}
}

Comments

Submitted to MNRAS Letters