Globular cluster population of the HST frontier fields galaxy J07173724+3744224

• Published in: arXiv.org 2018-07
• Main Authors: Carlson, Nathan L, Sultanova, Madina R, Sandanuwan P Kalawila Vithanage, Barkhouse, Wayne A, Gihan L Ipita Kaduwa Gamage, Rude, Cody M, Lopez-Cruz, Omar
• Format: Article
• Language: English
• Subjects: Elliptical galaxies; Field of view; Galactic clusters; Galactic evolution; Galaxies; Galaxy distribution; Globular clusters; Hubble Space Telescope; Population; Space telescopes
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1711.09500

We present the first measurement of the globular cluster population surrounding the elliptical galaxy J07173724+3744224 (z=0.1546). This galaxy is located in the foreground in the field-of-view of the Hubble Space Telescope (HST) Frontier Fields observations of galaxy cluster MACS J0717.5+3745 (z=0.5458). Based on deep HST ACS F435W, F606W, and F814W images, we find a total globular cluster population of N_tot = 3441 +/- 1416. Applying the appropriate extinction correction and filter transformation from ACS F814W to the Johnson V-band, we determine that the host galaxy has an absolute magnitude of M_V = -22.2. The specific frequency was found to be S_N = 4.5 +/- 1.8. The radial profile of the globular cluster system was best fit using a powerlaw of the form \(\sigma\sim R^{-0.6}\), with the globular cluster population found to be more extended than the halo light of the host galaxy (\(\sigma_{halo}\sim R^{-1.7}\)). The F435W-F814W colour distribution suggests a bimodal population, with red globular clusters 1-3x more abundant than blue clusters. These results are consistent with the host elliptical galaxy J07173724+3744224 having formed its red metal-rich GCs in situ, with the blue metal-poor globular clusters accreted from low-mass galaxies.