Simulating point spread functions for the James Webb Space Telescope with WebbPSF

Perrin, Marshall D.; Soummer, Rémi; Elliott, Erin; Lallo, Matthew; Sivaramakrishnan, Anand

doi:10.1117/12.925230

Cited by 140 publications

(130 citation statements)

References 10 publications

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“…We used WebbPSF (Perrin et al 2012), the official JWST PSF simulation tool to generate a set of four broadband PSFs of 5 × 5 centred at λ 1 = 5.6 µm, λ 2 = 11.3 µm, λ 3 = 18.0 µm and λ 4 = 25.5 µm in order to cover the spectral range of MIRI. These broadband PSFs were generated from a set of 20 monochromatic PSFs assuming flat spectral energy distribution of the source, and oversampled at four times the pixel size of the detector, Fig.…”

Section: Jwst Psf Simulationsmentioning

confidence: 99%

Convolution kernels for multi-wavelength imaging

Boucaud

Bocchio

Abergel

et al. 2016

A&A

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Astrophysical images issued from different instruments and/or spectral bands often require to be processed together, either for fitting or comparison purposes. However each image is affected by an instrumental response, also known as point-spread function (PSF), that depends on the characteristics of the instrument as well as the wavelength and the observing strategy. Given the knowledge of the PSF in each band, a straightforward way of processing images is to homogenise them all to a target PSF using convolution kernels, so that they appear as if they had been acquired by the same instrument. We propose an algorithm that generates such PSF-matching kernels, based on Wiener filtering with a tunable regularisation parameter. This method ensures all anisotropic features in the PSFs to be taken into account. We compare our method to existing procedures using measured Herschel/PACS and SPIRE PSFs and simulated JWST/MIRI PSFs. Significant gains up to two orders of magnitude are obtained with respect to the use of kernels computed assuming Gaussian or circularised PSFs. A software to compute these kernels is available at https://github.com/aboucaud/pypher

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Section: Jwst Psf Simulationsmentioning

confidence: 99%

Convolution kernels for multi-wavelength imaging

Boucaud

Bocchio

Abergel

et al. 2016

A&A

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“…A comparison between this PSF model of a single support strut and the WEBBPSF 2 model (Perrin et al 2012(Perrin et al , 2014 of the entire pupil is show in right panel of Figure 1. We can see that the analytical model correctly captures the main features of the diffraction spike, in particular the location of the minima in x-direction, from which we determine a = 4.85 cm.…”

Section: The Psf Modelmentioning

confidence: 99%

In the Crosshair: Astrometric Exoplanet Detection with WFIRST's Diffraction Spikes

Spergel

Lanz

2018

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WFIRST will conduct a coronagraphic program of characterizing the atmospheres of planets around bright nearby stars. When observed with the WFIRST Wide Field Camera, these stars will saturate the detector and produce very strong diffraction spikes. In this paper, we forecast the astrometric precision that WFIRST can achieve by centering on the diffraction spikes of highly saturated stars. This measurement principle is strongly facilitated by the WFIRST H4RG detectors, which confine excess charges within the potential well of saturated pixels. By adopting a simplified analytical model of the diffraction spike caused by a single support strut obscuring the telescope aperture, integrated over the WFIRST pixel size, we predict the performance of this approach with the Fisher-matrix formalism. We discuss the validity of the model and find that 10 µas astrometric precision is achievable with a single 100 s exposure of a R AB = 6 or a J AB = 5 star. We discuss observational limitations from the optical distortion correction and pixel-level artifacts, which need to be calibrated at the level of 10 -20 µas so as to not dominate the error budget. To suppress those systematics, we suggest a series of short exposures, dithered by at least several hundred pixels, to reach an effective per-visit astrometric precision of better than 10 µas. If this can be achieved, a dedicated WFIRST GO program will be able to detect Earth-mass exoplanets with orbital periods of 1 yr around stars within a few pc as well as Neptunelike planets with shorter periods or around more massive or distant stars. Such a program will also enable mass measurements of many anticipated direct-imaging exoplanet targets of the WFIRST coronagraph and a "starshade" occulter.

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“…2. Monochromatic PSFs simulated at λ 1 " 7.7 µm and λ 2 " 25.25 µm, using the simulation tool WebbPSF [13] for the instrument MIRIM on board the JWST.…”

Section: Instrument Modelmentioning

confidence: 99%

“…4. Moreover, non-stationary PSF is a set of monochromatic PSFs simulated on a discrete wavelength grid that covers the whole spectral range of the instrument, simulated with WebbPSF [13] the official PSF simulator of mission JWST.…”

Section: A Application To Jwst/mirimmentioning

confidence: 99%

Restoration from multispectral blurred data with non-stationary instrument response

Hadj-Youcef

Orieux

Fraysse

et al. 2017

2017 25th European Signal Processing Conference (EUSIPCO)

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Abstract-In this paper we propose an approach of image restoration from multispectral data provided by an imaging system. We specifically address two topics: (i) Development of a multi-wavelength direct model for non-stationary instrument response that includes a spatial convolution and a spectral integration, (ii) Implementation of multispectral image restoration using a regularized least-square, based on a quadratic criterion and minimized by a gradient algorithm. We test our approach on simulated data of the Mid-InfraRed Instrument IMager (MIRIM) of the James Webb Space Telescope (JWST). Our method shows a clear increase of spatial resolution compare to conventional methods.

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Simulating point spread functions for the James Webb Space Telescope with WebbPSF

Cited by 140 publications

References 10 publications

Convolution kernels for multi-wavelength imaging

Convolution kernels for multi-wavelength imaging

In the Crosshair: Astrometric Exoplanet Detection with WFIRST's Diffraction Spikes

Restoration from multispectral blurred data with non-stationary instrument response

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