IEEC Weekly Colloquium – Stellar Tidal Streams as Galaxy Formation diagnostic

While major mergers are quite rare at present, minor mergers and satellite disruptions – that result in stellar streams – should be common, and are indeed seen in the Milky Way and the Andromeda galaxy. In the last years, the Stellar Tidal Stream Survey (PI. Martinez-Delgado) has obtained ultra-deep, wide-field imaging of some nearby spiral galaxies, based on data taken with small robotic telescopes (0.1-0.5-meter).

These images have revealed for first time external views of such stellar tidal streams at unprecedented sensitivity and detail. In this talk, I present the recent results of our systematic survey of stellar tidal streams in a sample of nearby galaxies with the ultimate aim of estimating the frequency, morphology and stellar luminosity/mass distribution of the detected stellar streams in the Local Volume. I also discuss how the comparison of these observations with state-of-the-art L-CDM and W-CDM cosmological simulations of this phenomenon can provide a direct and stringent test of hierarchical structure formation on this small scale.