SPECTRAL ENERGY DISTRIBUTION FITTING WITH MARKOV CHAIN MONTE CARLO: METHODOLOGY AND APPLICATION TO z = 3.1 Ly{alpha}-EMITTING GALAXIES

Journal Article · Sat Aug 20 04:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/737/2/47· OSTI ID:21579970

Acquaviva, Viviana; Gawiser, Eric ^[1]; Guaita, Lucia ^[2]

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1. Department of Physics and Astronomy, Rutgers, State University of New Jersey, Piscataway, NJ 08854 (United States)
2. Departimento de Astronomia y Astrofisica, Universidad Catolica de Chile, Santiago (Chile)

We present GalMC, a Markov Chain Monte Carlo (MCMC) algorithm designed to fit the spectral energy distributions (SEDs) of galaxies to infer physical properties such as age, stellar mass, dust reddening, metallicity, redshift, and star formation rate. We describe the features of the code and the extensive tests conducted to ensure that our procedure leads to unbiased parameter estimation and accurate evaluation of uncertainties. We compare its performance to grid-based algorithms, showing that the efficiency in CPU time is {approx}100 times better for MCMC for a three-dimensional parameter space and increasing with the number of dimensions. We use GalMC to fit the stacked SEDs of two samples of Lyman alpha emitters (LAEs) at redshift z = 3.1. Our fit reveals that the typical LAE detected in the IRAC 3.6 {mu}m band has age = 0.67 [0.37-1.81] Gyr and stellar mass = 3.2 [2.5-4.2] x 10{sup 9} M{sub sun}, while the typical LAE not detected at 3.6 {mu}m has age = 0.06 [0.01-0.2] Gyr and stellar mass = 2 [1.1-3.4] x 10{sup 8} M{sub sun}. The SEDs of both stacks are consistent with the absence of dust. The data do not significantly prefer exponential with respect to constant star formation history. The stellar populations of these two samples are consistent with the previous study by Lai et al., with some differences due to the improved modeling of the stellar populations. A constraint on the metallicity of z = 3.1 LAEs from broadband photometry, requiring Z < Z{sub sun} at 95% confidence, is found here for the first time.

• OSTI ID: 21579970
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 737; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ALGORITHMS
DUSTS
ENERGY SPECTRA
GALAXIES
MASS
MATHEMATICAL LOGIC
RED SHIFT
SPECTRA
STARS