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SDSS J2222+2745, at z = 0.489, is one of the few currently known lens clusters with multiple images of a background (z = 2.801) quasar with measured time delays. We combine imaging from the Hubble Space Telescope (HST) with recent Multi…

Astrophysics of Galaxies · Physics 2022-12-21 A. Acebron , C. Grillo , P. Bergamini , G. B. Caminha , P. Tozzi , A. Mercurio , P. Rosati , G. Brammer , M. Meneghetti , M. Nonino , E. Vanzella

Accurate and reliable energy time series prediction is of great significance for power generation planning and allocation. At present, deep learning time series prediction has become the mainstream method. However, the multi-scale time…

Machine Learning · Computer Science 2025-08-08 Wei Li , Zixin Wang , Qizheng Sun , Qixiang Gao , Fenglei Yang

The observable time delays between the multiple images of strong lensing systems with time variable sources can provide us with some valuable information to probe the expansion history of the Universe. Estimation of these time delays can be…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Amir Aghamousa , Arman Shafieloo

Strong gravitational lensing of time variable sources such as quasars and supernovae creates observable time delays between the multiple images. Time delays can provide a powerful cosmographic probe through the "time delay distance"…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-18 Alireza Hojjati , Alex G. Kim , Eric V. Linder

Time-delay cosmography can be used to infer the Hubble parameter $H_0$ by measuring the relative time delays between multiple images of gravitationally-lensed quasars. A few of such systems have already been used to measure $H_0$: their…

Instrumentation and Methods for Astrophysics · Physics 2022-08-03 L. Biggio , A. Domi , S. Tosi , G. Vernardos , D. Ricci , L. Paganin , G. Bracco

The spatial resolution of astronomical images is limited by atmospheric turbulence and diffraction in the telescope optics, resulting in blurred images. This makes it difficult to accurately measure the brightness of blended objects because…

Instrumentation and Methods for Astrophysics · Physics 2023-05-31 Kevin Michalewicz , Martin Millon , Frédéric Dux , Frédéric Courbin

Astrometric calibration of images with a small field of view is often inferior to the internal accuracy of the source detections due to the small number of accessible guide stars. One important experiment with such challenges is the Hubble…

Instrumentation and Methods for Astrophysics · Physics 2019-11-06 Fan Tian , Tamás Budavári , Amitabh Basu , Stephen H. Lubow , Richard L. White

Strongly lensed quasars can be used to constrain cosmological parameters through time-delay cosmography. Models of the lens masses are a necessary component of this analysis. To enable time-delay cosmography from a sample of…

A degeneracy in strong lens model is shown analytically. The observed time delays and quasar image positions might {\it not} uniquely determine the concentration and the extent of the lens galaxy halo mass distribution. Simply hardwiring…

Astrophysics · Physics 2009-11-07 HongSheng Zhao , Bo Qin

Strong gravitational lensing and microlensing of supernovae (SNe) are emerging as a new probe of cosmology and astrophysics in recent years. We provide an overview of this nascent research field, starting with a summary of the first…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-12 Sherry H. Suyu , Ariel Goobar , Thomas Collett , Anupreeta More , Giorgos Vernardos

We present a determination of the Hubble constant from the joint, free-form analysis of 8 strongly, quadruply lensing systems. In the concordance cosmology, we find $H_0 = 71.8^{+3.9}_{-3.3}\,\mathrm{km}\,\mathrm{s}^{-1}\,\mathrm{Mpc}^{-1}$…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-22 Philipp Denzel , Jonathan P. Coles , Prasenjit Saha , Liliya L. R. Williams

Quantifying the parameters and corresponding uncertainties of hundreds of strongly lensed quasar systems holds the key to resolving one of the most important scientific questions: the Hubble constant ($H_{0}$) tension. The commonly used…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-11 Kuan-Wei Huang , Geoff Chih-Fan Chen , Po-Wen Chang , Sheng-Chieh Lin , Chia-Jung Hsu , Vishal Thengane , Joshua Yao-Yu Lin

Challenges inherent to high-resolution and high signal-to-noise data as well as model degeneracies can cause systematic biases in analyses of strong lens systems. In the past decade, the number of lens modeling methods has significantly…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-10 A. Galan , G. Vernardos , Q. Minor , D. Sluse , L. Van de Vyvere , M. Gomer

Realizing Refsdal's original idea from 1964, we present estimates of the Hubble constant that are complementary to and potentially competitive with those of other cosmological probes. We use the observed positions of 89 multiple images,…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-27 C. Grillo , P. Rosati , S. H. Suyu , I. Balestra , G. B. Caminha , A. Halkola , P. L. Kelly , M. Lombardi , A. Mercurio , S. A. Rodney , T. Treu

Weak gravitational lensing is one of the most powerful tools for cosmology, while subject to challenges in quantifying subtle systematic biases. The Point Spread Function (PSF) can cause biases in weak lensing shear inference when the PSF…

Instrumentation and Methods for Astrophysics · Physics 2021-12-13 Tianqing Zhang , Rachel Mandelbaum , The LSST Dark Energy Science Collaboration

The time delay measured between the images of gravitationally lensed quasars probes a combination of the angular diameter distance to the source-lens system and the mass density profile of the lens. Observational campaigns to measure such…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-22 Kfir Blum , Emanuele Castorina , Marko Simonović

Time-delay cosmography leverages strongly lensed quasars to measure the Universe's current expansion rate, H_0, independently from other methods. While the latest TDCOSMO results relied mainly on quadruply lensed quasars, doubly lensed…

This work presents AstroPT, an autoregressive pretrained transformer developed with astronomical use-cases in mind. The AstroPT models presented here have been pretrained on 8.6 million $512 \times 512$ pixel $grz$-band galaxy postage stamp…

Instrumentation and Methods for Astrophysics · Physics 2024-05-27 Michael J. Smith , Ryan J. Roberts , Eirini Angeloudi , Marc Huertas-Company

Time-series forecasting has gained significant attention in machine learning due to its crucial role in various domains. However, most existing forecasting models rely heavily on point-wise loss functions like Mean Square Error, which treat…

Machine Learning · Computer Science 2025-07-16 Dilfira Kudrat , Zongxia Xie , Yanru Sun , Tianyu Jia , Qinghua Hu

We introduce the STAR-MELT Python package that we developed to facilitate the analysis of time-resolved emission line spectroscopy of young stellar objects. STAR-MELT automatically extracts, identifies and fits emission lines. We summarise…