RADIATIVE TRANSFER MODELING OF Ly{alpha} EMITTERS. I. STATISTICS OF SPECTRA AND LUMINOSITY
- Yale Center for Astronomy and Astrophysics, Yale University, New Haven, CT 06520 (United States)
- Department of Astrophysical Sciences, Princeton University, Peyton Hall, Ivy Lane, Princeton, NJ 08544 (United States)
- Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)
- Institucio Catalana de Recerca i Estudis Avancats, Barcelona (Spain)
We combine a cosmological reionization simulation with box size of 100 h {sup -1} Mpc on a side and a Monte Carlo Ly{alpha} radiative transfer code to model Ly{alpha} Emitters (LAEs) at z {approx} 5.7. The model introduces Ly{alpha} radiative transfer as the single factor for transforming the intrinsic Ly{alpha} emission properties into the observed ones. Spatial diffusion of Ly{alpha} photons from radiative transfer results in extended Ly{alpha} emission and only the central part with high surface brightness can be observed. Because of radiative transfer, the appearance of LAEs depends on density and velocity structures in circumgalactic and intergalactic media as well as the viewing angle, which leads to a broad distribution of apparent (observed) Ly{alpha} luminosity for a given intrinsic Ly{alpha} luminosity. Radiative transfer also causes frequency diffusion of Ly{alpha} photons. The resultant Ly{alpha} line is asymmetric with a red tail. The peak of the Ly{alpha} line shifts toward longer wavelength and the shift is anti-correlated with the apparent-to-intrinsic Ly{alpha} luminosity ratio. The simple radiative transfer model provides a new framework for studying LAEs. It is able to explain an array of observed properties of z {approx} 5.7 LAEs in Ouchi et al., producing Ly{alpha} spectra, morphology, and apparent Ly{alpha} luminosity function (LF) similar to those seen in observation. The broad distribution of apparent Ly{alpha} luminosity at fixed UV luminosity provides a natural explanation for the observed UV LF, especially the turnover toward the low luminosity end. The model also reproduces the observed distribution of Ly{alpha} equivalent width (EW) and explains the deficit of UV bright, high EW sources. Because of the broad distribution of the apparent-to-intrinsic Ly{alpha} luminosity ratio, the model predicts effective duty cycles and Ly{alpha} escape fractions for LAEs.
- OSTI ID:
- 21451133
- Journal Information:
- Astrophysical Journal, Vol. 716, Issue 1; Other Information: DOI: 10.1088/0004-637X/716/1/574; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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