Microlensing with an advanced contour integration algorithm: Green's theorem to third order, error control, optimal sampling and limb darkening

Bozza, V.

doi:10.1111/j.1365-2966.2010.17265.x

Cited by 140 publications

(107 citation statements)

References 36 publications

(47 reference statements)

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“…Dealing with some of these effects poses no significant difficulties, and requires only simple extensions to the basic SBLM; in particular, however, computing the magnification of an extended (as opposed to point‐like) source can take around two orders of magnitude longer than the corresponding calculations under the point‐source approximation (e.g. Vermaak ; Gould ; Bozza ). Unfortunately, finite‐source effects generally cannot be ignored when dealing with planetary signals (Vermaak ), so in such cases the claims about the algorithm's speed are seemingly invalidated.…”

Section: Discussionmentioning

confidence: 99%

Evolutionary-algorithm-based analysis of gravitational microlensing light curves

Rajpaul

2012

Monthly Notices of the Royal Astronomical Society

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A new algorithm developed to perform autonomous fitting of gravitational microlensing light curves is presented. The new algorithm is conceptually simple, versatile and robust, and parallelizes trivially; it combines features of extant evolutionary algorithms with some novel ones, and fares well on the problem of fitting binary-lens microlensing light curves, as well as on a number of other difficult optimization problems. Success rates in excess of 90 per cent are achieved when fitting synthetic though noisy binary-lens light curves, allowing no more than 20 min per fit on a desktop computer; this success rate is shown to compare very favourably with that of both a conventional (iterated simplex) algorithm, and a more state-ofthe-art, artificial neural network based approach. As such, this work provides proof of concept for the use of an evolutionary algorithm as the basis for real-time, autonomous modelling of microlensing events. Further work is required to investigate how the algorithm will fare when faced with more complex and realistic microlensing modelling problems; it is, however, argued here that the use of parallel computing platforms, such as inexpensive graphics processing units, should allow fitting times to be constrained to under an hour, even when dealing with complicated microlensing models. In any event, it is hoped that this work might stimulate some interest in evolutionary algorithms, and that the algorithm described here might prove useful for solving microlensing and/or more general model-fitting problems.

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Section: Discussionmentioning

confidence: 99%

Evolutionary-algorithm-based analysis of gravitational microlensing light curves

Rajpaul

2012

Monthly Notices of the Royal Astronomical Society

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“…This corresponds to where the projected position of the lens is slightly interior to the projected source surface. We calculated the magnification factor with finite source size using the RT-model developed by V. Bozza (Bozza et al 2018;Bozza 2010;Skowron & Gould 2012). The magnification factor decreases for ρ /u > 1.1 and the calculation approaches that of the point-lens with point-source as the finite size of the star becomes diminishingly relevant.…”

Section: General Characterizationsmentioning

confidence: 99%

Microlensing of radially pulsating stars

Sajadian

Ignace

2020

Monthly Notices of the Royal Astronomical Society

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Here, we study the microlensing of radially pulsating stars. Discerning and characterizing the properties of distant, faint pulsating stars is achievable through high-cadence microlensing observations. Combining stellar variability period with microlensing gives the source distance, type, and radius and helps better determine the lens parameters. Considering periodically variations in their radius and surface temperature, their microlensing light curves are resulted from multiplication of the magnification factor with variable finite size effect by the intrinsic brightness curves of pulsing source. The variable finite source size due to pulsation can be significant for transit and single microlensing and while caustic-crossing features. This kind of deviation in the magnification factor is considerable when the ratio of the source radius to the projected lens-source distance is in the range of ρ /u ∈ [0.4, 10] and its duration is short and in the same order of the time of crossing the source radius. Other deviations due to variable source intensity and its area make colored and periodic deviations which are asymmetric with respect to the signs of pulsation phase. The positive phases makes deviations with larger amplitude that negative phase. These deviations dominate in filters with short wave lengths (e.g., B−band). The position of magnification peaks in microlensing of variable stars varies and this displacement differs in different filters.

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“…To model such events, we must use a methodology that accounts for the finite source size. The two most common algorithms for this are contour integration via Stokes' Theorem (Gould & Gaucherel 1997;Bozza 2010) and various refinements of ray shooting maps (Kayser, Refsdal & Stabell 1986;Dong et al 2006;Bennett & Rhie 1996). In Sections 4-5 below we describe our strategy, that is based on the magnification map approach.…”

Section: The Binary Microlensing Modelmentioning

confidence: 99%

Microlensing observations rapid search for exoplanets: morse code for GPUs

McDougall

Albrow

2015

Mon. Not. R. Astron. Soc.

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The rapid analysis of ongoing gravitational microlensing events has been integral to the successful detection and characterisation of cool planets orbiting low mass stars in the Galaxy. In this paper we present an implementation of search and fit techniques on Graphical Processing Unit hardware. The method allows for the rapid identification of candidate planetary microlensing events and their subsequent followup for detailed characterisation.

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Microlensing with an advanced contour integration algorithm: Green's theorem to third order, error control, optimal sampling and limb darkening

Cited by 140 publications

References 36 publications

Evolutionary-algorithm-based analysis of gravitational microlensing light curves

Evolutionary-algorithm-based analysis of gravitational microlensing light curves

Microlensing of radially pulsating stars

Microlensing observations rapid search for exoplanets: morse code for GPUs

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