English
Related papers

Related papers: LYMAN-ALPHA FOREST CORRELATIONS USING NEIGHBOR COU…

200 papers

We evaluate the performance of the Lyman-$\alpha$ forest weak gravitational lensing estimator of Metcalf et al. on forest data from hydrodynamic simulations and ray-traced simulated lensing potentials. We compare the results to those…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-30 Patrick Shaw , Rupert A. C. Croft , R. Benton Metcalf

We compare the low redshift (z ~ 0.1) Lyman-alpha forest from hydrodynamical simulations with data from the Cosmic Origin Spectrograph (COS). We find tension between the observed number of lines with b-parameters in the range 25-45 km/s and…

Astrophysics of Galaxies · Physics 2017-04-19 M. Viel , M. G. Haehnelt , J. S. Bolton , T. -S. Kim , E. Puchwein , F. Nasir , B. P. Wakker

We introduce a two-particle correlation function (2PCF) for the Milky Way, constructed to probe spatial correlations in the orthogonal directions of the stellar disk in the Galactic cylindrical coordinates of $R$, $\phi$, and $z$. We use…

Astrophysics of Galaxies · Physics 2023-01-16 Austin Hinkel , Susan Gardner , Brian Yanny

The first positive detection of the X-ray background fluctuations at small angular scales is reported. ROSAT PSPC archive pointed observations are used to measure fluctuations at scales of 0.03 - 0.4 deg. The pointings have been selected…

Astrophysics · Physics 2007-05-23 Andrzej M. Soltan , Michael J. Freyberg

We study the clustering properties of X-ray sources detected in the wide area ($\sim 2 $deg$^{2}$) bright, contiguous XMM-{\em Newton}/2dF survey. We detect 432 objects to a flux limit of $5\times 10^{-15}$ ergcm$^{-2}$s$^{-1}$ in the soft…

Astrophysics · Physics 2009-11-10 S. Basilakos , M. Plionis , A. Georgakakis , I. Georgantopoulos

We present predictions for the fluorescent Lyman-alpha emission signature arising from photoionized, optically thick structures in Smoothed Particle Hydrodynamic (SPH) cosmological simulations of a Lambda-CDM universe using a Monte Carlo…

Cosmology and Nongalactic Astrophysics · Physics 2010-01-15 Juna A. Kollmeier , Zheng Zheng , Romeel Davé , Andrew Gould , Neal Katz , Jordi Miralda-Escudé , David H. Weinberg

We examine the statistics of the low-redshift Lyman-alpha forest from smoothed particle hydrodynamic simulations in light of recent improvements in the estimated evolution of the cosmic ultraviolet background (UVB) and recent observations…

We have developed a parameter-independent method to detect local maxima of the two-point correlation function. By applying it to two samples of rich Abell clusters of galaxies with redshift limits z<0.08 and z<0.12 we detect three maxima…

Astrophysics · Physics 2007-05-23 Veikko Saar , Erik Tago , Jaan Einasto , Maret Einasto , Heinz Andernach

Spectroscopy of ten quasars obtained with the Goddard High Resolution Spectrograph (GHRS) of the Hubble Space Telescope (HST) is presented. A clustering analysis reveals an excess of nearest neighbor line pairs on velocity scales of 250-750…

Astrophysics · Physics 2008-11-26 C. D. Impey , C. E. Petry , K. P. Flint

Two-point correlation functions of cosmic microwave background polarization provide a physically independent probe of the surprising suppression of correlations in the cosmic microwave background temperature anisotropies at large angular…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Amanda Yoho , Simone Aiola , Craig J. Copi , Arthur Kosowsky , Glenn D. Starkman

The angular two-point correlation function between background QSOs and foreground galaxies induced by gravitational lensing is derived. It is shown that the shape of this correlation function depends sensitively on the spectrum of the…

Astrophysics · Physics 2007-05-23 Matthias Bartelmann

We present the Lyman-$\alpha$ flux power spectrum measurements of the XQ-100 sample of quasar spectra obtained in the context of the European Southern Observatory Large Programme "Quasars and their absorption lines: a legacy survey of the…

We use the LUQAS sample of 27 high resolution, high signal-to-noise QSO absorption spectra (Kim et al. 2004) and the results from Croft et al. (2002) together with a suite of high-resolution hydro-dynamical simulations run with the…

We present the first spectroscopic measurement of the spatial cross-correlation function between damped Lyman alpha systems (DLAs) and Lyman break galaxies (LBGs). We obtained deep u'BVRI images of nine QSO fields with 11 known z ~ 3 DLAs…

Astrophysics · Physics 2009-11-13 J. Cooke , A. M. Wolfe , E. Gawiser , J. X. Prochaska

Recent observations have discovered long (up to ~110 Mpc/h), opaque Gunn-Peterson troughs in the z ~ 5.5 Lyman-alpha forest, which are challenging to explain with conventional models of the post-reionization intergalactic medium. Here we…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-11 Frederick B. Davies , George D. Becker , Steven R. Furlanetto

In order to construct accurate point sources simulations at the frequencies relevant to 21 cm experiments, the angular correlation of radio sources must be taken into account. Using the 74 MHz VLSS survey, we measured the angular 2-point…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Angelica de Oliveira-Costa , John Capodilupo

We quantify the angular clustering of radio galaxies in the NVSS and FIRST radio surveys using the two-point correlation function and the moments of counts-in-cells - both important points of comparison with theory. These investigations…

Astrophysics · Physics 2009-11-07 Chris Blake , Jasper Wall

It is shown how wavelets may be used to analyse the absorption properties of the Lya forest. The Discrete Wavelet Transform of a QSO spectrum is used to decompose the light fluctuations that comprise the forest into orthogonal wavelets. It…

Astrophysics · Physics 2009-10-31 A. Meiksin

In Lyman-alpha forest measurements it is generally assumed that quasars are mere background light sources which are uncorrelated with the forest. Gravitational lensing of the quasars violates this assumption. This effect leads to a…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-14 Marilena LoVerde , Stefanos Marnerides , Lam Hui , Brice Menard , Adam Lidz