A Comparison of Approaches in Fitting Continuum SEDs

Abstract

We present a detailed comparison of two approaches, the use of a pre-calculated database and simulated annealing (SA), for fitting the continuum spectral energy distribution (SED) of astrophysical objects whose appearance is dominated by surrounding dust. While pre-calculated databases are commonly used to model SED data, only few studies to date employed SA due to its unclear accuracy and convergence time for this specific problem. From a methodological point of view, different approaches lead to different fitting quality, demand on computational resources and calculation time. We compare the fitting quality and computational costs of these two approaches for the task of SED fitting to provide a guide to the practitioner to find a compromise between desired accuracy and available resources. To reduce uncertainties inherent to real datasets, we introduce a reference model resembling a typical circumstellar system with 10 free parameters. We derive the SED of the reference model with our code MC3D at 78 logarithmically distributed wavelengths in the range [0.3um, 1.3mm] and use this setup to simulate SEDs for the database and SA. Our result shows directly the applicability of SA in the field of SED modeling, since the algorithm regularly finds better solutions to the optimization problem than a pre-calculated database. As both methods have advantages and shortcomings, a hybrid approach is preferable. While the database provides an approximate fit and overall probability distributions for all parameters deduced using Bayesian analysis, SA can be used to improve upon the results returned by the model grid.

14 pages, 4 figures, accepted for publication in the Research in Astronomy and Astrophysics

References in corpus (23)

• Dust Grain Size Distributions and Extinction in the Milky Way, LMC, and SMC
• Spectral Energy Distributions of T Tauri Stars With Passive Circumstellar Disks
• Interpreting Spectral Energy Distributions from Young Stellar Objects. II. Fitting observed SEDs using a large grid of pre-computed models
• Interpreting Spectral Energy Distributions from Young Stellar Objects. I. A grid of 200,000 YSO model SEDs
• Protoplanetary Disk Structures in Ophiuchus
• Accretion Disks Around Young Objects. II. Tests of Well-Mixed Models with Ism Dust
• High Resolution Submillimeter Constraints on Circumstellar Disk Structure
• Radiative Equilibrium and Temperature Correction in Monte Carlo Radiation Transfer
• A Submillimeter View of Circumstellar Dust Disks in $\rho$ Ophiuchus
• Dust grain growth in rho-Ophiuchi protoplanetary disks
• Probing dust grain evolution in IM Lupi's circumstellar disc. Multi-wavelength observations and modelling of the dust disc
• A Spitzer Census of Transitional Protoplanetary Disks with AU-Scale Inner Holes
• The Circumstellar Disk of the Butterfly Star in Taurus
• The Nature of Transition Circumstellar Disks I. The Ophiuchus Molecular Cloud
• Spectral Energy Distributions of Passive T Tauri Disks: Inclination
• MC3D - 3D Continuum Radiative Transfer, Version 2
• The T Tauri star RY Tau as a case study of the inner regions of circumstellar dust disks
• On the stratified dust distribution of the GG Tau circumbinary ring
• The circumstellar disc in the Bok globule CB 26: Multi-wavelength observations and modelling of the dust disc and envelope
• Deep MIPS Observations of the IC 348 Nebula: Constraints on the Evolutionary State of Anemic Circumstellar Disks and the Primordial-to-Debris Disk Transition
• Structural and compositional properties of brown dwarf disks: the case of 2MASS J04442713+2512164
• Continuum and line modelling of discs around young stars. I. 300000 disc models for Herschel/GASPS
• The circumstellar disk of HH 30. Searching for signs of disk evolution with multi-wavelength modeling

Cited by in corpus (3)

• OTS44: Disk and accretion at the planetary border
• A homogeneous analysis of disks around brown dwarfs
• CLIcK: a Continuum and Line fItting Kit for circumstellar disks