| Low-mass stars are formed in molecular clouds, but only in the densest and coldest regions within molecular clouds called "Dense Cores." This thesis presents a wide variety of observations, from centimeter to millimeter wavelengths observed with both single dish and interferometers, that allow us to study the star formation process in the Perseus molecular cloud complex starting from the large-scale structure using low-density gas tracers and then zooming into the smaller scales where dense cores form stars. Here we address the following open questions in star formation: (1) do changes in the environment affect chemical abundances in a molecular cloud?; (2) what is the mass function of substructures in molecular clouds?; (3) how are dense cores connected with their environment?; (4) what are the earliest stage of star formation?. We use large-scale molecular line and extinction maps to show that within a single molecular cloud large variations in the molecular abundance are found, we also study the reliability and limitations of 12CO, 13CO, and C18O (1-0) lines to trace the total column density. We also study the robustness of sub-structures in molecular clouds and its associated mass function, and we show that the results are affected by the molecular cloud hierarchical structure. Our study of dense cores presents, for the first time in a single tracer, observations of a sharp transition between gas with supersonic and subsonic turbulence using large scale NH3 maps observed with the GBT towards several regions, this result provides a strong test on theories of star formation. We present a "First Hydrostatic Core" candidate (an object only found in numerical calculations formed in the earliest stage of star formations) inside a starless (Spitzer) dense core, which is identified using dust continuum and molecular line interferometric observations (using SMA and CARMA) and it is also modeled using a radiative transfer code to confirm the presence of a central young object. |
