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We investigate the capability of the \textit{Nancy Grace Roman Space Telescope's (Roman)} Wide-Field Instrument (WFI) G150 slitless grism to detect red, quiescent galaxies based on the current reference survey. We simulate dispersed images…

Astrophysics of Galaxies · Physics 2026-02-25 Zhiyuan Guo , Bhavin Joshi , Chris. W. Walter , M. A. Troxel

Optimal extraction of cosmological information from observations of the Cosmic Microwave Background critically relies on our ability to accurately undo the distortions caused by weak gravitational lensing. In this work, we demonstrate the…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-07 Thomas Flöss , William R. Coulton , Adriaan J. Duivenvoorden , Francisco Villaescusa-Navarro , Benjamin D. Wandelt

Photometric wide-area observations in the next decade will be capable of detecting a large number of galaxy-scale strong gravitational lenses, increasing the gravitational lens sample size by orders of magnitude. To aid in forecasting and…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-02 Giovanni Ferrami , Stuart Wyithe

WL measurements have well-known shear estimation biases, which can be partially corrected for with the use of image simulations. We present an analysis of simulated images that mimic HST/ACS observations of high-redshift galaxy clusters,…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-26 B. Hernandez-Martin , T. Schrabback , H. Hoekstra , N. Martinet , J. Hlavacek-Larrondo , L. E. Bleem , M. D. Gladders , B. Stalder , A. A. Stark , M. Bayliss

We present results from a set of simulations designed to constrain the weak lensing shear calibration for the Hyper Suprime-Cam (HSC) survey. These simulations include HSC observing conditions and galaxy images from the Hubble Space…

We present a study of weak lensing shear measurements for simulated galaxy images at radio wavelengths. We construct a simulation pipeline into which we can input galaxy images of known ellipticity, and with which we then simulate…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Prina Patel , Filipe B. Abdalla , David J. Bacon , Barnaby Rowe , Oleg Smirnov , Rob J. Beswick

Medical image segmentation models struggle with rare abnormalities due to scarce annotated pathological data. We propose DiffAug a novel framework that combines textguided diffusion-based generation with automatic segmentation validation to…

Computer Vision and Pattern Recognition · Computer Science 2025-08-26 Maham Nazir , Muhammad Aqeel , Francesco Setti

We present realistic forecasts for the constraining power of the Nancy Grace Roman Space Telescope on fundamental cosmological parameters, with particular emphasis on the absolute neutrino mass scale, using full-shape analyzes of the galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-17 Francesco Spezzati , Yun Wang , Andrew Hearin

We propose a new technique to directly measure the shapes of dark matter halos of galaxies using weak gravitational lensing. Extending the standard galaxy-galaxy lensing method, we show that the shape parameters of the mass distribution of…

Astrophysics · Physics 2009-10-31 Priyamvada Natarajan , Alexandre Refregier

The slitless grism on the Nancy Grace Roman Space Telescope will enable deep near-infrared spectroscopy over a wide field of view. We demonstrate Roman's capability to detect Ly$\alpha$ galaxies at $z>7$ using a multi-position-angle (PA)…

Astrophysics of Galaxies · Physics 2023-05-03 Isak G. B. Wold , Sangeeta Malhotra , James E. Rhoads , Vithal Tilvi , Austen Gabrielpillai

Weak gravitational lensing surveys are rapidly becoming important tools to probe directly the mass density fluctuations in the universe and its background dynamics. Earlier studies have shown that it is possible to model the statistics of…

Astrophysics · Physics 2009-11-07 Patrick Valageas , Andrew J. Barber , Dipak Munshi

Current and upcoming wide-field, ground-based, broad-band imaging surveys promise to address a wide range of outstanding problems in galaxy formation and cosmology. Several such uses of ground-based data, especially weak gravitational…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Rachel Mandelbaum , Christopher M. Hirata , Alexie Leauthaud , Richard J. Massey , Jason Rhodes

We present a novel approach to reconstruct gas and dark matter projected density maps of galaxy clusters using score-based generative modeling. Our diffusion model takes in mock SZ and X-ray images as conditional inputs, and generates…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-16 Alan Hsu , Matthew Ho , Joyce Lin , Carleen Markey , Michelle Ntampaka , Hy Trac , Barnabás Póczos

We present a realistic 2000 deg$^{2}$ H$\alpha$ galaxy mock catalog with $1<z<2$ for the Nancy Grace Roman Space Telescope galaxy redshift survey, the High Latitude Spectroscopic Survey (HLSS), created using Galacticus, a semi-analytical…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-06 Zhongxu Zhai , Chia-Hsun Chuang , Yun Wang , Andrew Benson , Gustavo Yepes

We present an empirical method for estimating the underlying redshift distribution N(z) of galaxy photometric samples from photometric observables. The method does not rely on photometric redshift (photo-z) estimates for individual…

Astrophysics · Physics 2008-11-26 Marcos Lima , Carlos E. Cunha , Hiroaki Oyaizu , Joshua Frieman , Huan Lin , Erin S. Sheldon

We present an algorithm capable of detecting diffuse, dim sources of any size in an astronomical image. These sources often defeat traditional methods for source finding, which expand regions around points of high intensity. Extended…

Instrumentation and Methods for Astrophysics · Physics 2016-01-05 T. Butler-Yeoman , M. Frean , C. P. Hollitt , D. W. Hogg , M. Johnston-Hollitt

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

Diffusion models are at the vanguard of generative AI research with renowned solutions such as ImageGen by Google Brain and DALL.E 3 by OpenAI. Nevertheless, the potential merits of diffusion models for communication engineering…

Information Theory · Computer Science 2023-11-17 Mehdi Letafati , Samad Ali , Matti Latva-aho

Diffusion models for image generation have been a subject of increasing interest due to their ability to generate diverse, high-quality images. Image generation has immense potential in medical imaging because open-source medical images are…

Computer Vision and Pattern Recognition · Computer Science 2025-02-13 Benoit Freiche , Anthony El-Khoury , Ali Nasiri-Sarvi , Mahdi S. Hosseini , Damien Garcia , Adrian Basarab , Mathieu Boily , Hassan Rivaz