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

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The FIRST (Faint Images of the Radio Sky at Twenty Centimeters) survey now covers 1550 square degrees of sky where $07^{h}16 < \alpha < 17^{h}40$ and $28^{\circ}.3 < \delta < 42^{\circ}$. This yields a catalog of 138,665 sources above the…

Astrophysics · Physics 2009-10-28 C. M. Cress , D. J. Helfand , R. H. Becker , M. D. Gregg , R. L. White

The upcoming WEAVE-QSO survey will target a high density of quasars over a large area, enabling the reconstruction of the 3D density field through Lyman-$\alpha$ tomography over unprecedented volumes smoothed on intermediate scales…

Lyman alpha absorber correlations contain information about the underlying density distribution associated with a particular class of absorbers. As such, they provide an opportunity to independently measure the "bias" of the Lyman alpha…

Astrophysics · Physics 2016-01-27 Romeel Davé , Neal Katz , David H. Weinberg

We present a study of the effect of High Column Density (HCD) systems on the Lyman \alpha forest correlation function on large scales. We study the effect both numerically, by inserting HCD systems on mock spectra for a specific model, and…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Andreu Font-Ribera , Jordi Miralda-Escudé

Cosmological studies of the Lyman-Alpha (Lya) forest typically constrain parameters using two-point statistics. However, higher-order statistics, such as the three-point function (or its Fourier counterpart, the bispectrum) offer additional…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-28 Roger de Belsunce , James M. Sullivan , Patrick McDonald

The Ly$\alpha$ forest, a series of HI absorption lines in the quasar spectra, is a powerful tool for probing the large-scale structure of the intergalactic medium. Its three-dimensional (3D) correlation and cross-correlations with quasars…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-23 Koichiro Nakashima , Atsushi J. Nishizawa , Kentaro Nagamine , Yuri Oku , Ikkoh Shimizu

We provide a perturbative effective field theory (EFT) description for anisotropic (redshift-space) correlations between the Lyman alpha forest and a generic biased tracer of matter, which could be represented by quasars, high-redshift…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-23 Anton Chudaykin , Mikhail M. Ivanov

The Lyman-$\beta$ forest refers to a region in the spectra of distant quasars that lies between the rest-frame Lyman-$\beta$ and Lyman-$\gamma$ emissions. The forest in this region is dominated by a combination of absorption due to resonant…

Spectroscopy with HST/STIS Echelle and VLT/UVES of the bright QSO HE 0515-4414 (z_em =1.73, B = 15.0) offers for the first time the opportunity to study the Lyman alpha forest in the redshift range 0.9 < z < 1.7 at a resolution ~ 10 km/s.…

Astrophysics · Physics 2009-11-07 Eckart Janknecht , Robert Baade , Dieter Reimers

Using high resolution (R ~ 45000), high S/N (20-50) VLT/UVES observations covering the Lyman-alpha forest at 1.5 < z < 2.4 combined with similar observations at z > 2.4 from the literature, we have presented the redshift evolution of the…

Astrophysics · Physics 2009-11-06 Tae-Sun Kim , Stefano Cristiani , Sandro D'Odorico

Two-point correlation functions (2PCF) are widely used to characterize how points cluster in space. In this work, we study the problem of measuring the 2PCF over a large set of points, restricted to a subset satisfying a property of…

Computer Vision and Pattern Recognition · Computer Science 2026-04-08 Max Hamilton , Daniel Sheldon , Subhransu Maji

A homogeneous sample of 99 moderate resolution QSO spectra at z > 1.7 were presented in Paper I, including 39 previously unpublished spectra from the Multiple Mirror Telescope. The statistics of the Lyman alpha forest were discussed. In…

Astrophysics · Physics 2009-10-31 J. Scott , J. Bechtold , A. Dobrzycki , V. Kulkarni

We use the Ly-$\alpha$ Mass Association Scheme (LyMAS; Peirani et al. 2014) to predict cross-correlations at $z=2.5$ between dark matter halos and transmitted flux in the Ly-$\alpha$ forest, and compare to cross-correlations measured for…

We review recent developments in the theory of the Lyman-alpha forest and their implications for the role of the forest as a test of cosmological models. Simulations predict a relatively tight correlation between the local Lya optical depth…

Astrophysics · Physics 2009-11-07 David H. Weinberg , Romeel Dav'e , Neal Katz , Juna A. Kollmeier

We present predictions of the correlation between the Lyman-alpha forest absorption in quasar spectra and the mass within \sim 5 Mpc/h (comoving) of the line of sight, using fully hydrodynamic and hydro-PM numerical simulations of the cold…

Astrophysics · Physics 2009-11-07 Patrick McDonald , Jordi Miralda-Escudé , Renyue Cen

The angular positions of quasars are deflected by the gravitational lensing effect of foreground matter. The Lyman-alpha forest seen in the spectra of these quasars is therefore also lensed. We propose that the signature of weak…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-21 Rupert A. C. Croft , Alessandro Romeo , R. Benton Metcalf

This paper describes a study of the Lyman-alpha forest absorption clouds along the quasar sightline Q0000-26 (zem=4.1). The spectrum was obtained with the High Resolution Spectrometer on the 10m Keck telescope. We derive accurate H I column…

Astrophysics · Physics 2009-10-28 Limin Lu , Wallace L. W. Sargent , Donna S. Womble , Masahide Takada-Hidai

We present the first clustering measurement of Strong Blended Lyman $\alpha$ (SBLA) absorption systems by measuring their cross-correlation with the Lyman $\alpha$ forest. SBLAs are a new population of absorbers detected within the Lyman…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-18 Ignasi Pérez-Ràfols , Matthew M. Pieri , Michael Blomqvist , Sean Morrison , Debopam Som , Andrei Cuceu

We investigate the 3-D matter distribution at z~2 with high resolution (R ~ 40000) spectra of QSO pairs and groups obtained with the UVES spectrograph at ESO VLT. Our sample is unique for the number density of objects and the variety of…

Astrophysics · Physics 2009-11-11 S. Cristiani , V. D'Odorico , F. Saitta , M. Viel , S. Bianchi , B. Boyle , S. Lopez , J. Maza , P. Outram