期刊
PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC
卷 125, 期 928, 页码 719-730出版社
UNIV CHICAGO PRESS
DOI: 10.1086/671228
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资金
- NASA [NNX12AI50G]
- NSF [IIS-1124794]
- Direct For Computer & Info Scie & Enginr
- Div Of Information & Intelligent Systems [1124794] Funding Source: National Science Foundation
- NASA [21501, NNX12AI50G] Funding Source: Federal RePORTER
Exponential, de Vaucouleurs, and Sersic profiles are simple and successful models for fitting two-dimensional images of galaxies. One numerical issue encountered in this kind of fitting is the pixel rendering and convolution (or correlation) of the models with the telescope point-spread function (PSF); these operations are slow, and easy to get slightly wrong at small radii. Here we exploit the realization that these models can be approximated to arbitrary accuracy with a mixture (linear superposition) of two-dimensional Gaussians (MoGs). MoGs are fast to render and fast to affine-transform. Most importantly, if you have a MoG model for the pixel-convolved PSF, the PSF-convolved, affine-transformed galaxy models are themselves MoGs and therefore very fast to compute, integrate, and render precisely. We present worked examples that can be directly used in image fitting; we are using them ourselves. The MoG profiles we provide can be swapped in to replace the standard models in any image-fitting code; they sped up model fitting
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