A new tool for image analysis based on Chebyshev rational functions: CHEF functions

Abstract

We introduce a new approach to the modelling of the light distribution of galaxies, an orthonormal polar base formed by a combination of Chebyshev rational functions and Fourier polynomials that we call CHEF functions, or CHEFs. We have developed an orthonormalization process to apply this basis to pixelized images, and implemented the method as a Python pipeline. The new basis displays remarkable flexibility, being able to accurately fit all kinds of galaxy shapes, including irregulars, spirals, ellipticals, highly compact and highly elongated galaxies. It does this while using fewer components that similar methods, as shapelets, and without producing artifacts, due to the efficiency of the rational Chebyshev polynomials to fit quickly decaying functions like galaxy profiles. The method is lineal and very stable, and therefore capable of processing large numbers of galaxies in a fast and automated way. Due to the high quality of the fits in the central parts of the galaxies, and the efficiency of the CHEF basis modeling galaxy profiles up to very large distances, the method provides highly accurate estimates of total galaxy fluxes and ellipticities. Future papers will explore in more detail the application of the method to perform multiband photometry, morphological classification and weak shear measurements.

16 pages, 21 figures, submitted to ApJ

References in corpus (10)

• Detailed Decomposition of Galaxy Images. II. Beyond Axisymmetric Models
• The Hubble Ultra Deep Field
• Galaxies in the Hubble Ultra Deep Field: I. Detection, Multiband Photometry, Photometric Redshifts, and Morphology
• Bayesian Galaxy Shape Measurement for Weak Lensing Surveys -I. Methodology and a Fast Fitting Algorithm
• Image Decomposition of Barred Galaxies and AGN Hosts
• The ALHAMBRA Project: A large area multi medium-band optical and NIR photometric survey
• Optimal filter systems for photometric redshift estimation
• Weak gravitational shear and flexion with polar shapelets
• Lensing signals in the Hubble Ultra-Deep Field using all 2nd order shape deformations
• Galaxy Modeling with Compound Elliptical Shapelets

Cited by in corpus (25)

• Unveiling the dynamical state of massive clusters through the ICL fraction
• J-PLUS: analysis of the intracluster light in the Coma cluster
• JWST reveals a possible $z\sim 11$ galaxy merger in triply-lensed MACS0647$-$JD
• CLASH: Accurate Photometric Redshifts with 14 HST bands in Massive Galaxy Cluster Cores
• Disentangling the ICL with the CHEFs: Abell 2744 as a case study
• A Neural Network Gravitational Arc Finder based on the Mediatrix filamentation Method
• The ALHAMBRA survey: reliable morphological catalogue of 22,051 early- and late-type galaxies
• J-PLUS: On the identification of new cluster members in the double galaxy cluster A2589 & A2593 using PDFs
• Crowded Field Galaxy Photometry: Precision Colors in the CLASH Clusters
• DAWIS, a Detection Algorithm with Wavelets for Intracluster light Studies
• Exponential shapelets: basis functions for data analysis of isolated features
• The impact from survey depth and resolution on the morphological classification of galaxies
• MUSE spectroscopy and deep observations of a unique compact JWST target, lensing cluster CLIO
• Dissecting the RELICS cluster SPT-CLJ0615-5746 through the intracluster light: confirmation of the multiple merging state of the cluster formation
• The intracluster light on Frontier Fields clusters Abell 370 and Abell S1063
• The ALHAMBRA survey: 2-D analysis of the stellar populations in massive early-type galaxies at z < 0.3
• RELICS: ICL Analysis of the $z=0.566$ merging cluster WHL J013719.8-08284
• The OTELO survey as a morphological probe. Last ten Gyr of galaxy evolution. The mass--size relation up to z=2
• Accurate PSF-matched photometry and photometric redshifts for the Extreme Deep Field with the Chebyshev-Fourier functions
• Euclid: Early Release Observations -- The Intracluster Light of Abell 2390
• Deep view of the intracluster light in the Coma cluster of galaxies
• Automated Transient Detection with Shapelet Analysis in Image-subtracted Data
• The intracluster light analysis of the most evolved systems of galaxies: fossil groups
• Independent Evidence for earlier formation epochs of fossil groups of galaxies through the intracluster light: the case for RX J100742.53+380046.6
• Effect of AGN on the morphological properties of their host galaxies in the local Universe