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The surface figure of x-ray mirrors can be improved by differential deposition of thin films. To achieve the required corrections, WSi2 layers of variable thickness were deposited through beam-defining apertures of different openings. The…

Optics · Physics 2025-06-03 Ch. Morawe , S. Labouré , F. Perrin , A. Vivo , R. Barrett

Numerical simulations with varying realism indicate an emergent principle -- multiphase condensation and large cavity power occur when the ratio of the cooling time to the free-fall time ($t_{\rm cool}/t_{\rm ff}$) falls below a threshold…

Astrophysics of Galaxies · Physics 2022-08-22 Kartick C Sarkar , Arjun Dey , Prateek Sharma

We propose a new point-spread function (PSF) deconvolution algorithm for images of galaxies hosting an active galactic nucleus (AGN), designed to simultaneously enhance the spatial resolution of the host galaxy and remove the bright central…

Astrophysics of Galaxies · Physics 2026-05-15 Ren Kawase , Takatoshi Shibuya , Kazunori Matsuda

Precise determination of galaxy cluster masses is crucial for establishing reliable mass-observable scaling relations in cluster cosmology. We employ graph neural networks (GNNs) to estimate galaxy cluster masses from radially sampled…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-14 Asif Iqbal , Subhabrata Majumdar , Elena Rasia , Gabriel W. Pratt , Daniel de Andres , Jean-Baptiste Melin , Weiguang Cui

We present results of N-body/gasdynamical simulations designed to investigate the evolution of X-ray clusters in a flat, low-density, cold dark matter (CDM) cosmogony. The density profile of the dark matter component can be fitted rather…

Astrophysics · Physics 2009-10-30 Vincent R. Eke , Julio F. Navarro , Carlos S. Frenk

We use high-resolution hydrodynamic simulations to investigate the density profile of hot gas in clusters of galaxies, adopting a variant of cold dark matter cosmologies and employing a cosmological N-body/smoothed particle hydrodynamics…

Astrophysics · Physics 2009-10-30 Tatsushi Suginohara , Jeremiah P. Ostriker

The projected gravitational potential of galaxy clusters is reflected in both their X-ray emission and their imprint on the images of background sources due to their gravitational lensing effects. Since these projections of the potential…

Astrophysics · Physics 2007-05-23 Matthias Bartelmann , Tsafrir S. Kolatt

We present the first results of a serendipitous search for clusters of galaxies in deep ROSAT-PSPC pointed observations at high galactic latitude. The survey is being carried out using a Wavelet based Detection Algorithm which is not biased…

Astrophysics · Physics 2016-08-30 P. Rosati , R. Della Ceca , R. Burg , C. Norman , R. Giacconi

I start by providing an updated summary of the penalized pixel-fitting (pPXF) method, which is used to extract the stellar and gas kinematics, as well as the stellar population of galaxies, via full spectrum fitting. I then focus on the…

Astrophysics of Galaxies · Physics 2017-01-11 Michele Cappellari

The point-spread function (PSF) is a fundamental property of any astronomical instrument. In interferometers, differing array configurations combined with their $uv$ coverage, and various weighting schemes can produce an irregular but…

Instrumentation and Methods for Astrophysics · Physics 2023-10-20 Jack F. Radcliffe , R. J. Beswick , A. P. Thomson , A. Njeri , T. W. B. Muxlow

Measurements of clustering in large-scale imaging surveys that make use of photometric redshifts depend on the uncertainties in the redshift determination. We have used light-cone simulations to show how the deprojection method successfully…

We describe several projects addressing the growth of galaxies and massive black holes, for which adaptive optics is mandatory to reach high spatial resolution but is also a challenge due to the lack of guide stars and long integrations. In…

Instrumentation and Methods for Astrophysics · Physics 2015-05-19 Richard Davies , Hauke Engel , Erin Hicks , Natascha Foerster Schreiber , Reinhard Genzel , Linda Tacconi , Frank Eisenhauer , Sebastian Rabien

In this paper we have made an attempt to derive the radial profiles of density and temperature of intracluster gas based on the two well-established facts at present: the X-ray observed surface brightness of clusters described by the…

Astrophysics · Physics 2009-10-31 Xiang-Ping Wu , Tzihong Chiueh

In the imaging process of an astronomical telescope, the deconvolution of its beam or Point Spread Function (PSF) is a crucial task. However, deconvolution presents a classical and challenging inverse computation problem. In scenarios where…

Instrumentation and Methods for Astrophysics · Physics 2024-03-05 Shulei Ni , Yisheng Qiu , Yunchun Chen , Zihao Song , Hao Chen , Xuejian Jiang , Huaxi Chen

A method for spatial deconvolution of spectra is presented. It follows the same fundamental principles as the ``MCS image deconvolution algorithm'' (Magain, Courbin, Sohy, 1998) and uses information contained in the spectrum of a reference…

Astrophysics · Physics 2009-10-31 F. Courbin , P. Magain , M. Kirkove , S. Sohy

(Abridged)We present a combined analysis of mass estimates in the central cores of galaxy clusters from the strong lensing, the X-ray measurements and the universal density profile (NFW). Special attention is paid to the questions…

Astrophysics · Physics 2009-10-31 Xiang-Ping Wu

The ill-posed problem of phase retrieval in optics, using one or more intensity measurements, has a multitude of applications using electromagnetic or matter waves. Many phase retrieval algorithms are computed on pixel arrays using discrete…

Image and Video Processing · Electrical Eng. & Systems 2022-09-21 J. A. Pollock , K. S. Morgan , L. C. P. Croton , M. K. Croughan , G. Ruben , N. Yagi , H. Sekiguchi , M. J. Kitchen

We address the question of how well the density profile of galaxy clusters can be determined by combining strong lensing and velocity dispersion data. We use cosmological dark matter simulations of clusters to test the reliability of the…

Astrophysics · Physics 2010-12-01 M. Meneghetti , M. Bartelmann , A. Jenkins , C. Frenk

In this Letter we present the radial temperature profiles of three X-ray clusters (A119, A2255 and A2256) reconstructed from a combination of the X-ray surface brightness measurements and the universal density profile as the underlying dark…

Astrophysics · Physics 2007-05-23 Yan-Jie Xue , Xiang-Ping Wu

This paper presents a framework for developing a live vision-correcting display (VCD) to address refractive visual aberrations without the need for traditional vision correction devices like glasses or contact lenses, particularly in…

Image and Video Processing · Electrical Eng. & Systems 2025-01-06 Akhilesh Balaji , Dhruv Ramu