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In this study, we explore gravitational lensing using more realistic dark matter halo models, moving beyond the limitations of spherical-collapse approximations. Through analytical calculations employing various mass functions, we address…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-13 Ali Tizfahm , Saeed Fakhry , Javad T. Firouzjaee , Antonino Del Popolo

In this work, we obtain measurements of the Hubble constant in the context of modified gravity theories. We set up our theoretical framework by considering viable cosmological $f(R)$ and $f(T)$ models, and we analyzed them through the use…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-07 Rocco D'Agostino , Rafael C. Nunes

We present a simultaneous analysis of 10 galaxy lenses having time-delay measurements. For each lens we derive a detailed free-form mass map, with uncertainties, and with the additional requirement of a shared value of the Hubble parameter…

Astrophysics · Physics 2009-11-11 P. Saha , J. Coles , A. V. Maccio' , L. L. R. Williams

The determination of the Hubble parameter H_0 is probably one of the most important applications of quasar lensing. The method, based on the measurement of the so-called ``time-delay'' between the lensed images of distant sources, e.g.,…

Astrophysics · Physics 2007-05-23 F. Courbin

We analyze strong gravitational lensing by a spherically symmetric mass distribution within the Einstein-Straus-de Sitter framework in a spatially open Universe with negative curvature ($k = -1$). Applying the theory to the lensed quasar…

General Relativity and Quantum Cosmology · Physics 2025-10-27 Mourad Guenouche

If the gravitational lens is surrounded by non-homoheneous plasma, in addition to the vacuum gravitational deflection, chromatic refraction occurs. Also, the speed of signal propagation decreases compared to vacuum. In this article, we…

General Relativity and Quantum Cosmology · Physics 2023-07-12 Gennady S. Bisnovatyi-Kogan , Oleg Yu. Tsupko

Inferring spatial curvature of the Universe with high-fidelity is a longstanding interest in cosmology. However, the strong degeneracy between dark energy equation-of-state parameter $w$ and curvature density parameter $\Omega_{\rm K}$ has…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-11 Yang Hu , Suhail Dhawan

Time-delay cosmography of lensed quasars has achieved 2.4% precision on the measurement of the Hubble constant, $H_0$. As part of an ongoing effort to uncover and control systematic uncertainties, we investigate three potential sources: 1-…

In this paper, we use a newly compiled sample of ultra-compact structure in radio quasars and strong gravitational lensing systems with quasars acting as background sources to constrain six spatially flat and non-flat cosmological models…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-07 Tonghua Liu , Shuo Cao , Xiaolei Li , Hao Zheng , Yuting Liu , Wuzheng Guo , Chenfa Zheng

The local expansion rate of the Universe is parametrized by the Hubble constant, $H_0$, the ratio between recession velocity and distance. Different techniques lead to inconsistent estimates of $H_0$. Observations of Type Ia supernovae…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-17 Inh Jee , Sherry Suyu , Eiichiro Komatsu , Christopher D. Fassnacht , Stefan Hilbert , Léon V. E. Koopmans

Strong gravitational lenses with measured time delay are a powerful tool to measure cosmological parameters, especially the Hubble constant ($H_0$). Recent studies show that by combining just three multiply-imaged AGN systems, one can…

We present the measurement of the Hubble Constant, $H_0$, with three strong gravitational lens systems. We describe a blind analysis of both PG1115+080 and HE0435-1223 as well as an extension of our previous analysis of RXJ1131-1231. For…

Gravitational lensing time delays are well known to depend on cosmological parameters, but they also depend on the details of the mass distribution of the lens. It is usual to model the mass distribution and use time-delay observations to…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Irshad Mohammed , Prasenjit Saha , Jori Liesenborgs

We present new measurements of the values of the Hubble constant, matter density, dark energy density, and dark energy density equation-of-state parameters from a full strong lensing analysis of the observed positions of 89 multiple images…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-24 C. Grillo , L. Pagano , P. Rosati , S. H. Suyu

Gravitational time delays offer unique, independent measurements of the Hubble constant, $H_0$. Precise measurements of $H_0$ stand as one of the most pressing challenges in modern cosmology, and to do so with time delays requires precise…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-19 D. M. Williams , T. Treu , S. Birrer , A. J. Shajib , K. C. Wong , T. Morishita , T. Schmidt , M. Stiavelli

We present a new determination of the time delay of the gravitational lens system HE1104-1805 ('Double Hamburger') based on a previously unpublished dataset. We argue that the previously published value of dt_(A-B)=0.73 years was affected…

Astrophysics · Physics 2009-11-07 R. Gil-Merino , L. Wisotzki , J. Wambsganss

Strongly lensed quasars can provide measurements of the Hubble constant ($H_{0}$) independent of any other methods. One of the key ingredients is exquisite high-resolution imaging data, such as Hubble Space Telescope (HST) imaging and…

In this paper we investigate the statistical properties of gravitational lenses for models in which a cosmological term decreases with time as $\Lambda \propto a^{-m}$, where $a$ is the scale factor and $m$ is a parameter ($0 \leq m < 3$).…

Astrophysics · Physics 2015-06-24 L. F. Bloomfield Torres , I. Waga

With future wide and deep cosmological sky surveys, a large number of gravitationally lensed, multiply imaged systems will be found. In addition to multiply imaged galaxies and quasars, sources will include transient events like supernovae…

Astrophysics · Physics 2009-11-13 Edvard Mortsell , Christoffer Sunesson

(Abridged) We perform a detailed analysis of the optical gravitational lens ER 0047-2808 imaged with WFPC2 on the Hubble Space Telescope. Using software specifically designed for the analysis of resolved gravitational lens systems, we focus…

Astrophysics · Physics 2008-11-26 Randall B. Wayth , Stephen J. Warren , Geraint F. Lewis , Paul C. Hewett