A simple prescription for simulating and characterizing gravitational arcs

Abstract

Simple models of gravitational arcs are crucial to simulate large samples of these objects with full control of the input parameters. These models also provide crude and automated estimates of the shape and structure of the arcs, which are necessary when trying to detect and characterize these objects on massive wide area imaging surveys. We here present and explore the ArcEllipse, a simple prescription to create objects with shape similar to gravitational arcs. We also present PaintArcs, which is a code that couples this geometrical form with a brightness distribution and adds the resulting object to images. Finally, we introduce ArcFitting, which is a tool that fits ArcEllipses to images of real gravitational arcs. We validate this fitting technique using simulated arcs and apply it to CFHTLS and HST images of tangential arcs around clusters of galaxies. Our simple ArcEllipse model for the arc, associated to a Sérsic profile for the source, recovers the total signal in real images typically within 10%-30%. The ArcEllipse+Sérsic models also automatically recover visual estimates of length-to-width ratios of real arcs. Residual maps between data and model images reveal the incidence of arc substructure. They may thus be used as a diagnostic for arcs formed by the merging of multiple images. The incidence of these substructures is the main factor preventing ArcEllipse models from accurately describing real lensed systems.

12 pages, 11 figures, accepted for publication in A&A

References in corpus (2)

• Multimodal nested sampling: an efficient and robust alternative to MCMC methods for astronomical data analysis
• Herschel observations of ortho- and para-oxidaniumyl (H2O+) in spiral arm clouds toward Sgr B2(M)

Cited by in corpus (27)

• The physical and chemical structure of Sagittarius B2, I. Three-dimensional thermal dust and free-free continuum modeling on 100 au to 45 pc scales
• Ubiquitous argonium (ArH${}^{+}$) in the diffuse interstellar medium -- a molecular tracer of almost purely atomic gas
• The ice composition in the disk around V883 Ori revealed by its stellar outburst
• Herschel observations of EXtra-Ordinary Sources: Analysis of the HIFI 1.2 THz Wide Spectral Survey Toward Orion KL I. Methods
• eXtended CASA Line Analysis Software Suite (XCLASS)
• Nested Sampling Methods
• A necklace of dense cores in the high-mass star forming region G35.20-0.74N: ALMA observations
• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -- XV. Steady Accretion from Global Collapse to Core Feeding in Massive Hub-filament System SDC335
• Chemical complexity in high-mass star formation: An observational and modeling case study of the AFGL 2591 VLA 3 hot core
• Fragmentation and disk formation in high-mass star formation: The ALMA view of G351.77-0.54 at 0.06" resolution
• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -- VIII. A search for hot cores by using C${}_2$H${}_5$CN, CH${}_3$OCHO and CH${}_3$OH lines
• ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): I. Detection of New Hot Corinos with ACA
• Evolution of complex organic molecules in hot molecular cores: Synthetic spectra at (sub-)mm wavebands
• Infrared-active phonon modes in monoclinic multiferroic MnWO4
• HyGAL: Characterizing the Galactic ISM with observations of hydrides and other small molecules -- I. Survey description and a first look toward W3(OH), W3 IRS5 and NGC 7538 IRS1
• Sulfur-bearing molecules in Orion KL
• The CO-H2 van der Waals complex and complex organic molecules in cold molecular clouds: a TMC-1C survey
• Clustered star formation at early evolutionary stages. Physical and chemical analysis of the young star-forming regions ISOSS J22478+6357 and ISOSS J23053+5953
• ALMA Observations of Ethyl Formate toward Orion KL
• Correlations of Methyl Formate (CH3OCHO), Dimethyl Ether (CH3OCH3) and Ketene (H2CCO) in High-mass Star-forming Regions
• The physical and chemical structure of Sagittarius B2 VIIIa. Dust and ionized gas contributions to the full molecular line survey of 47 hot cores
• The physical and chemical structure of Sagittarius B2, VIII. Full molecular line survey of hot cores
• HyGAL: Characterizing the Galactic ISM with observations of hydrides and other small molecules II. The absorption line survey with the IRAM 30 m telescope
• Deuterium fractionation of the starless core L 1498
• Identification of molecular line emission using Convolutional Neural Networks
• Beetroots: spatially-regularized Bayesian inference of physical parameter maps -- Application to Orion
• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -- X. Chemical differentiation among the massive cores in G9.62+0.19