A study of globular clusters in a lenticular galaxy in Hydra I from deep HST/ACS photometry

Abstract

We take advantage of exquisitely deep optical imaging data from HST/ACS in the F475W ($g_{F475W}$) and F606W ($V_{F606W}$) bands, to study the properties of the globular cluster (GC) population in the intermediate mass lenticular galaxy PGC 087327, in the Hydra I galaxy cluster. We inspect the photometric (magnitudes and color) and morphometric (compactness, elongation, etc.) properties of sources lying in an area of $\sim 19\times 19$ kpc centered on PGC 087327, and compare them with four neighbouring fields over the same HST/ACS mosaic. This allowed us to identify a list of GC candidates and to inspect their properties using a background decontamination method. Relative to the four comparison fields, PGC 087327 shows a robust overdensity of GCs, $N_{GC}=82\pm 9$. At the estimated magnitude of the galaxy, this number implies a specific frequency of $S_N=1.8\pm 0.7$. In spite of the short wavelength interval available with the $g_{F475W}$ and $V_{F606W}$ passbands, the color distribution shows a clear bimodality with a blue peak at $⟨g_{F475W}-V_{F606W}⟩=0.47\pm 0.05$ mag and a red peak at $⟨g_{F475W}-V_{F606W}⟩=0.62\pm 0.03$ mag. We also observe the typical steeper slope of the radial distribution of red GCs relative to blue ones. Thanks to the unique depth of the available data, we characterize the GC luminosity function (GCLF) well beyond the expected GCLF turn-over. We find $g_{F475W}^{TOM}=26.54\pm 0.10$ mag and $V_{F606W}^{TOM}=26.08\pm 0.09$ mag, which after calibration yields a distance of $D_{GCLF}=56.7\pm 4.3(statistical)\pm 5.2(systematic)$ Mpc.

Accepted for publication in A&A

References in corpus (5)

• The ACS Virgo Cluster Survey XV. The Formation Efficiencies of Globular Clusters in Early-Type Galaxies: The Effects of Mass and Environment
• Kinematics of the Local Universe XIII. 21-cm line measurements of 452 galaxies with the Nançay radiotelescope, JHK Tully-Fisher relation and preliminary maps of the peculiar velocity field
• Explaining the Color Distributions of Globular Cluster Systems in Elliptical Galaxies
• Globular Cluster Systems in Nearby Dwarf Galaxies: I. HST/ACS Observations and Dynamical Properties of Globular Clusters at Low Environmental Density
• On the Metallicity-Color Relations and Bimodal Color Distributions in Extragalactic Globular Cluster Systems

Cited by in corpus (4)

• VEGAS-SSS: Tracing Globular Cluster Populations in the Interacting NGC3640 Galaxy Group
• Looking into the faintEst WIth MUSE (LEWIS): Exploring the nature of ultra-diffuse galaxies in the Hydra I cluster III. Untangling UDG 32 from the stripped filaments of NGC 3314A with multi-wavelength data
• Looking into the faintEst WIth MUSE (LEWIS): Exploring the nature of ultra-diffuse galaxies in the Hydra-I cluster IV. A study of the Globular Cluster population in four UDGs
• VEGAS-SSS: An intra-group component in the globular cluster system of NGC 5018 group of galaxies using VST data