Tracing the Assembly History of NGC 1395

ESCUDERO, C.; FAIFER, F.; SMITH CASTELLI, A.; FORTE, J. C.; SESTO, L.; GONZÁLEZ, N.; SCALIA, M. C.

San Francisco

Congreso; Science and Evolution of Gemini Observatory 2018; 2018

Gemini Observatory

In the scenario of galaxy formation, it is clear that major fusions and tidal interactions play important roles. In the paradigm of hierarchical Lambda-CDM structure formation, massive early-type galaxies we see in the local Universe would have been built through a combination of two phases: in situ and ex situ formation. These two phases should leave their signatures both in their inner regions and in their halos. In this context, globular clusters (GCs) have proved to be important tools for examining the early stages of galaxy formation, and also to trace major star forming episodes in a galaxy. We used deep Gemini-South/GMOS g'r'i'z' images to study the GC system of the massive elliptical galaxy NGC1395, located in the Eridanus supergroup. The photometric analysis of the GC candidates reveals a clear colour bimodality distribution, indicating the presence of "blue" and "red" GC subpopulations. While a negative radial colour gradient is detected in the projected spatial distribution of the red GCs, the blue GCs display a shallow colour gradient. The blue GCs also display a remarkable shallow and extended surface density profile, suggesting a significant accretion of low-mass satellites in the outer halo of the galaxy. Regarding NGC1395 itself, the analysis of the deep Gemini/GMOS images shows a low surface brightness umbrella-like structure indicating, at least, one recent merger event. Recently, GMOS longslit observations were obtained from this galaxy. We will show here preliminary results of the stellar population analysis performed in the central region of NGC1395.