Search for streams in thick disk and halo of the Milky Way

Study on the substructures of Milky Way is very important because it can be used as the stage indicator in the formation process of the Galaxy. Substructures are made by clumps of stars with similar velocity, called as stellar streams. We searched for the stellar streams in thick disk and stellar halo of the Milky Way using data from Geneva-Copenhagen survey. We built velocity curves from data and applied the wavelet transform to find dense area in the velocity distribution. For the significace test, peaks on the wavelet transform of the data are reduced using wavelet transform based on Monte Carlo simulation. We found five streams on thick disk and two in stellar halo. Based on the metallicity distribution, it is shown that both thick disk and halo streams have similar range of metallicity, thus we classified them as dynamical stream.