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The Nancy Grace Roman Space Telescope will implement a devoted weak gravitational lensing program with its High Latitude Wide Area Survey. For cosmological purposes, a critical step in Roman image processing is to combine dithered…

Instrumentation and Methods for Astrophysics · Physics 2025-12-09 Kaili Cao , Christopher M. Hirata , Katherine Laliotis , Masaya Yamamoto , Emily Macbeth , M. A. Troxel

One challenge for applying current weak lensing analysis tools to the Nancy Grace Roman Space Telescope is that individual images will be undersampled. Our companion paper presented an initial application of Imcom - an algorithm that builds…

We present algorithms and software for constructing high-precision difference images to detect and measure transients, such as microlensing events, in crowded stellar fields using the Nancy Grace Roman Space Telescope. Our method generates…

Instrumentation and Methods for Astrophysics · Physics 2024-12-11 Michael D Albrow

In this paper, we present strip-map mode spaceborne Synthetic Aperture Radar (SAR) imaging with the focus on Doppler centroid frequency estimation. The non-zero Doppler centroid frequency is the result of non-zero squint angle which if it…

Signal Processing · Electrical Eng. & Systems 2025-08-01 Shahrokh Hamidi

The shear signal required for weak lensing analyses is small, so any detector-level effects which distort astronomical images can contaminate the inferred shear. The Nancy Grace Roman Space Telescope (Roman) will fly a focal plane with 18…

Instrumentation and Methods for Astrophysics · Physics 2022-02-09 Jahmour J. Givans , Ami Choi , Anna Porredon , Jenna K. C. Freudenburg , Christopher M. Hirata , Robert J. Hill , Christopher Bennett , Roger Foltz , Lane Meier

Precise centroid estimation plays a critical role in accurate astrometry using telescope images. Conventional centroid estimation fits a template point spread function (PSF) to the image data. Because the PSF is typically not known to high…

Instrumentation and Methods for Astrophysics · Physics 2015-05-27 Chengxing Zhai , Mike Shao , Renaud Goullioud , Bijan Nemati

The Nancy Grace Roman Space Telescope, set to launch in 2026, will bring unprecedented precision to measurements of weak gravitational lensing. Because weak lensing is an inherently small signal, it is imperative to minimize systematic…

Instrumentation and Methods for Astrophysics · Physics 2025-12-09 Katherine Laliotis , Emily Macbeth , Christopher M. Hirata , Kaili Cao , Masaya Yamamoto , Michael Troxel

The High Latitude Survey of the Nancy Grace Roman Space Telescope is expected to measure the positions and shapes of hundreds of millions of galaxies in an area of 2220 deg$^2$. This survey will provide high-quality weak lensing data with…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-09 Chien-Hao Lin , Rachel Mandelbaum , M. A. Troxel , Christopher M. Hirata , Mike Jarvis

The Nancy Grace Roman Space Telescope will carry out a wide-field imaging and slitless spectroscopic survey of Type Ia Supernovae to improve our understanding of dark energy. Crucial to this endeavor is obtaining supernova spectra…

NASA's Nancy Grace Roman Space Telescope (Roman) will provide an opportunity to study dark energy with unprecedented precision and accuracy using several techniques, including measurements of high-$z$ Type Ia Supernovae (SNe Ia, $z \lesssim…

Instrumentation and Methods for Astrophysics · Physics 2026-04-17 Lauren Aldoroty , Daniel Scolnic , Arun Kannawadi , Rob Knop , Benjamin Rose , Rebekah Hounsell , Michael Troxel

The upcoming Nancy Grace Roman Space Telescope will carry out a wide-area survey in the near infrared. A key science objective is the measurement of cosmic structure via weak gravitational lensing. Roman data will be undersampled, which…

Measuring the centroid of a spectral line is a common problem in astronomy. Many methods have been devised to overcome limitations due to either noise in the spectra or asymmetric profiles, the most common of which are the intensity…

Instrumentation and Methods for Astrophysics · Physics 2018-09-28 Richard Teague , Daniel Foreman-Mackey

For weak gravitational lensing cosmology with the forthcoming Nancy Grace Roman Space Telescope, image coaddition, or construction of oversampled images from undersampled ones, is a critical step in the image processing pipeline. In the…

Instrumentation and Methods for Astrophysics · Physics 2026-01-19 Kaili Cao , Christopher M. Hirata , Katherine Laliotis , Masaya Yamamoto , Emily Macbeth , M. A. Troxel

Weak gravitational lensing has emerged as a powerful tool for investigating the matter distribution in the Universe and how it has evolved over cosmic time. The Wide Field Instrument (WFI) on the Nancy Grace Roman Space Telescope (Roman)…

Instrumentation and Methods for Astrophysics · Physics 2025-12-08 Katherine Laliotis , Christopher M. Hirata , Emily Macbeth , Kaili Cao

The Nancy Grace Roman Space Telescope will survey a large area of the sky at near-infrared wavelengths with its Wide Field Instrument (WFI). The performance of the 18 WFI H4RG-10 detectors will need to be well-characterized and regularly…

Instrumentation and Methods for Astrophysics · Physics 2023-09-04 Phani Datta Velicheti , John F. Wu , Andreea Petric

The Nancy Grace Roman Space Telescope (Roman) is an observatory for both wide-field observations and coronagraphy that is scheduled for launch in the mid 2020's. Part of the planned survey is a deep, cadenced field or fields that enable…

Instrumentation and Methods for Astrophysics · Physics 2021-07-07 David Rubin , Aleksandar Cikota , Greg Aldering , Andy Fruchter , Saul Perlmutter , Masao Sako

Gravitational lens modeling of spatially resolved sources is a challenging inverse problem with many observational constraints and model parameters. We examine established pixel-based source reconstruction algorithms for de-lensing the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Amitpal Tagore , Charles Keeton

The Nancy Grace Roman Space Telescope (Roman) mission is expected to launch in the mid-2020s. Its weak lensing program is designed to enable unprecedented systematics control in photometric measurements, including shear recovery,…

Instrumentation and Methods for Astrophysics · Physics 2020-12-07 M. A. Troxel , H. Long , C. M. Hirata , A. Choi , M. Jarvis , R. Mandelbaum , K. Wang , M. Yamamoto , S. Hemmati , P. Capak

The Nancy Grace Roman Space Telescope's (RST) Wide Field Imager (WFI) is equipped with a slitless prism that can be used for spectroscopic discovery and follow-up of explosive transients at high redshift as part of its High Latitude Time…

Instrumentation and Methods for Astrophysics · Physics 2023-07-03 Greg Aldering , David Rubin , Benjamin Rose , Rebekah Hounsell , Saul Perlmutter , Susana Deustua

Pixel lensing, gravitational microlensing of unresolved stars, is potentially much more sensitive and much more widely applicable than is generally recognized. I give explicit expressions for the pixel noise induced by a time-variable PSF,…

Astrophysics · Physics 2008-11-26 Andrew Gould
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