DETAILED DECOMPOSITION OF GALAXY IMAGES. II. BEYOND AXISYMMETRIC MODELS

By C. Peng, Luis C. Ho, Christopher Impey, Hans-Walter Rix. 2009

1,372 citations recorded by the source corpus.

We present a two-dimensional (2D) fitting algorithm (Galfit, ver. 3) with new capabilities to study the structural components of galaxies and other astronomical objects in digital images. Our technique improves on previous 2D fitting algorithms by allowing for irregular, curved, logarithmic and power-law spirals, ring, and truncated shapes in otherwise traditional parametric functions like the Sérsic, Moffat, King, Ferrer, etc., profiles. One can mix and match these new shape features freely, with or without constraints, and apply them to an arbitrary number of model components of numerous profile types, so as to produce realistic-looking galaxy model images. Yet, despite the potential for extreme complexity, the meaning of the key parameters like the Sérsic index, effective radius, or luminosity remains intuitive and essentially unchanged. The new features have an interesting potential for use to quantify the degree of asymmetry of galaxies, to quantify low surface brightness tidal features beneath and beyond luminous galaxies, to allow more realistic decompositions of galaxy subcomponents in the presence of strong rings and spiral arms, and to enable ways to gauge the uncertainties when decomposing galaxy subcomponents. We illustrate these new features by way of several case studies that display various levels of complexity.

Subfields: Astronomy and Astrophysics, Computer Vision and Pattern Recognition, Instrumentation

View Paper: https://www.semanticscholar.org/paper/0122685a9f55fe5f6a8210188895d0a6921482fd

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Citations in the corpus

ON THE EVOLUTION OF THE MOLECULAR GAS FRACTION OF STAR-FORMING GALAXIES (2011, neutral): “0.2 (Peng et al. 2010).”
The behaviour of dark matter associated with four bright cluster galaxies in the 10 kpc core of Abell 3827 (2015, methodology): “In the optical HST imaging, we use GALFIT (Peng et al. 2010) to simultaneously fit the light distribution from the four bright galaxies and the two stars.”
The DEEP3 Galaxy Redshift Survey: the impact of environment on the size evolution of massive early-type galaxies at intermediate redshift (2011, methodology): “In agreement with our previous analysis, we find that within the high-mass segment of the early-type galaxy population the size–stellar mass relation varies with environment, such that galaxies in high-density regions are larger at a given stellar mass. Finally, at low surface brightness levels (i.e”
Galaxy And Mass Assembly (GAMA): mass–size relations of z < 0.1 galaxies subdivided by Sérsic index, colour and morphology (2014, methodology): “The mosaics along with the GAMA input catalogue are fed into SIGMA (Structural Investigation of Galaxies via Model Analysis; Kelvin et al. 2012) an automated front-end wrapper which uses a range of image analysis software (such as Source Extractor, Bertin & Arnouts 1996; PSF Extractor, Bertin 2013 a”
Early type galaxies have been the predominant morphological class for massive galaxies since only z~1 (2011, methodology): “In relation to the SDSS imaging, although the NYU catalog already provides structural parameters obtained using Sérsic fits to the galaxies, for the sake of consistency with our methodology, we ran GALFIT on the SDSS images of these galaxies to obtain structural parameters.”
Galaxy and Mass Assembly (GAMA): survey diagnostics and core data release (2010, methodology): “As described in full in Kelvin et al. (in preparation), we use the GALFIT3 package (Peng et al. 2010) to fit all galaxies to the SDSS DR6 rpet < 22.0 mag.”
The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. VII. Properties of the Host Galaxy and Constraints on the Merger Timescale (2017, methodology): “0.5 (Peng et al. 2010) to fit the 2D surface brightness profile of NGC 4993 with a standard Sérsic function that is parameterized by the Sérsic index, n, the effective radius, re, and me, the surface brightness at re.”
BULGE GROWTH AND QUENCHING SINCE z = 2.5 IN CANDELS/3D-HST (2014, methodology): “GALFIT takes into account the convolution of the model with the point-spread-function (PSF).”
Gravitational lensing analysis of the Kilo-Degree Survey (2015, methodology): “This catalogue is based on GALFIT galaxy profile fitting (Peng et al. 2010) of HST imaging data, and provides disc and bulge parameters in various wavebands including the F606W filter which is a good match to the KiDS r band.”
STELLAR KINEMATICS OF z ∼ 2 GALAXIES AND THE INSIDE-OUT GROWTH OF QUIESCENT GALAXIES, (2012, neutral): “3.0.2; Peng et al. 2010).”
The Binary Neutron Star Event LIGO/Virgo GW170817 160 Days after Merger: Synchrotron Emission across the Electromagnetic Spectrum (2018, neutral): “0.5 (Peng et al. 2010).”
GALAXY STRUCTURE AND MODE OF STAR FORMATION IN THE SFR–MASS PLANE FROM z ∼ 2.5 TO z ∼ 0.1 (2011, methodology): “…package (Barden et al. 2009) or equivalent procedures were used to pre-determine the sky background and the neighboring sources that need to be simultaneously fit or masked, and to automate fitting Sersic profiles to the 2D surface brightness distributions with GALFIT (C. Y. Peng et al. 2010).”
THE SCUBA-2 COSMOLOGY LEGACY SURVEY: ALMA RESOLVES THE REST-FRAME FAR-INFRARED EMISSION OF SUB-MILLIMETER GALAXIES (2014, methodology): “We fit a Sérsic profile to each model source using the code galfit (Peng et al. 2010), and find that the half-light size of the model sources is recovered accurately at all values of SNR and Sérsic index (Rrece /Rinpute = 0.99± 0.01; 1-σ dispersion ± 0.2).”
A Comprehensive Study of Galaxies at z ∼ 9–16 Found in the Early JWST Data: Ultraviolet Luminosity Functions and Cosmic Star Formation History at the Pre-reionization Epoch (2022, methodology): “To investigate the morphological properties of our galaxy candidates, we fit our galaxy candidates with the Sérsic profile using GALFIT (Peng et al. 2010).”
THE ASSEMBLY OF MILKY-WAY-LIKE GALAXIES SINCE z ∼ 2.5 (2013, methodology): “First, a two-dimensional Sersic (1968) model, convolved with the PSF, was fit to the stacks using the GALFIT code (Peng et al. 2010).”
THE ATACAMA COSMOLOGY TELESCOPE: ACT-CL J0102−4915 “EL GORDO,” A MASSIVE MERGING CLUSTER AT REDSHIFT 0.87 (2011, methodology): “For total magnitudes we use the SExtractor MAG_AUTO values (with a Kron factor of 2.5) and we measure colors within the galaxy effective radii Re which were computed using GALFIT (version 3.0, Peng et al. 2010) to fit each galaxy to a Sérsic (1968) model from the PSF-convolved i−band images.”
Galaxy And Mass Assembly (GAMA): the galaxy stellar mass function at z < 0.06 (2011, methodology): “A natural explanation for this functional form was suggested by Peng et al. (2010b).”