Chemodynamics in Blue Compact Dwarf galaxies: II Zw 33 and Mrk 600

CAMPUZANO CASTRO F.; V. FIRPO; BOSCH G.; HÄGELE G. F.

La Serena, Chile

Congreso; Segunda reunión AAA-SOCHIAS; 2018

SOCHIAS - AAA

We performed a kinematic study of five star-formation regions belonging to two Blue Compact Dwarf galaxies (BCDs): II Zw 33 and Mrk 600, using high resolution spectroscopic data obtained with the MIKE spectrograph mounted at the Clay telescope (LCO). The spectra present very complex emission-line profiles showing multiple Gaussian components and in order to analyze the kinematics of these star-forming regions we developed a Python code, based on the Non-Linear Least-Square Minimization and Curve-Fitting (LMFit) package and using a statistical method to analyse the goodness of the inclusion of a new Gaussian in the model. We used the components fitted to estimate the physical conditions (electron densities and temperatures), ionic and total chemical abundances of several atomic species and the ionization degree on each star-forming region. To do that we use the direct method which requires accurate measurements of the temperature sensitive weak auroral emission-lines. The high quality of our spectra allow us to deconvolve these weak lines in kinematics components using the results of the fittings for the strong lines with similar ionization potential as the initial guess and only varying their amplitudes. Using these chemodynamic results we continue with the comparative study of the evolutionary stages of the different star-forming knots belonging to a BCD taking into account e.g. the N/O and S/O ratios and the effective temperature of the radiation fields estimated from their ionization degree using the η and η? diagrams as well as the probable origin (e.g. the mixing layer scenario or projection effects) of the different kinematical components.