VEGAS-SSS. A VST survey of elliptical galaxies in the southern hemisphere: analysis of small stellar systems. Testing the methodology on the globular cluster system in NGC3115

Abstract

We present a study of globular clusters (GCs) and other small stellar systems (SSSs) in the field of NGC3115, observed as part of the VEGAS imaging survey, carried out with the VST telescope. We use deep g and i data of NGC3115, a well-studied lenticular galaxy with excellent scientific literature. This is fundamental to test the methodologies, verify the results, and probe the capabilities of the VEGAS-SSS. Leveraging the large field of view of the VST allow us to accurately study of the distribution and properties of SSSs as a function of galactocentric distance Rgc, well beyond ~20 galaxy effective radii, in a way not often possible. Our analysis of colors, magnitudes and sizes of SSS candidates confirms the results from existing studies, some of which carried out with 8-10m class telescopes, and further extends them to unreached Rgc distances, with similar accuracy. We find a color bimodality for the GC population and a r1/4 profile for the surface density of GCs as for the galaxy light profile. The radial color gradient of blue and red GCs previously found, for instance by the SLUGGS survey, is further extended out to the largest Rgc inspected, ~65 kpc. The surface density profiles of blue and red GCs taken separately are well approximated by a r1/4 density profile, with the fraction of blue GCs being slightly larger at larger Rgc. We do not find hints of a trend for the red GC and for the GC turnover magnitude to vary with radius, but we observe a ~0.2 mag difference in the turnover magnitude of the blue and red GCs subpopulations. Inspecting SSS sizes and colors we obtained a list of UCDs and GC candidates suitable for future spectroscopic follow-up. In conclusion, our study shows the reliability of the methodologies developed to study SSSs in the field of bright early-type galaxies, and the great potential of the VEGAS survey to produce original results on SSSs science.

arXiv comment21 pages, 22 figures, A&A accepted

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Cited by in corpus (5)

• The Fornax Deep Survey with VST. I. The extended and diffuse stellar halo of NGC~1399 out to 192 kpc
• VEGAS-SSS II: Comparing the globular cluster systems in NGC3115 and NGC1399 using VEGAS and FDS survey data
• The Fornax Cluster VLT Spectroscopic Survey. I - VIMOS spectroscopy of compact stellar systems in the Fornax core region
• The SLUGGS survey: Exploring the globular cluster systems of the Leo II group and their global relationships
• The assembly history of the nearest S0 galaxy NGC 3115 from its kinematics out to six half-light radii