Protostars and Planets VI, Heidelberg, July 15-20, 2013

Poster 1H027

Bayesian SED Fitting of YSOs in Cygnus-X

Martinez-Galarza, Rafael (Harvard-Smithsonian CfA)
Hora, Joseph (Harvard-Smithsonian CfA)
Azimlu, Mohaddesseh (Harvard-Smithsonian CfA)
Smith, Howard (Harvard-Smithsonian CfA)

We present a Montecarlo Bayesian tool to fit the spectral energy distributions (SEDs) of young stellar objects (YSOs), based on the Robitaille et al. 2006 grid of YSO SED models. Given a set of observations, the method computes the probability distribution functions (PDFs) for the model parameters and illustrate model degeneracies that should be taken into account in the interpretation of the results. We use the tool to fit the optical to mid-infrared SEDs of a collection of ∼800 intermediate-mass YSOs in the Cygnus-X star-forming region and derive posterior PDFs for physical parameters of the sample, such as YSO mass, age and external extinction. Our derived values for age and extinction values agree with independent measurements. We find that the present degeneracies (such as the mass-age degeneracy) can jeopardize some of the parameters derived with SED fitting, specially for Class IIa YSOs, where we find a significant under-estimation of the YSO mass. The method is automated and can be used with any set of YSO photometry.

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