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Related papers: Systematic Continuum Errors in the Lyman-Alpha For…

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We present 40 fully hydrodynamical numerical simulations of the intergalactic gas that gives rise to the Ly-alpha forest. We make artificial spectra from each and measure three output parameters: the mean flux, a measure of the most common…

Confronting measurements of the Lyman-$\alpha$ forest with cosmological hydrodynamical simulations has produced stringent constraints on models of particle dark matter and the thermal and ionization state of the intergalactic medium. We…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-20 Nabendu Kumar Khan , Girish Kulkarni , James S. Bolton , Martin G. Haehnelt , Vid Iršič , Ewald Puchwein , Shikhar Asthana

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

The intergalactic neutral hydrogen which is responsible for the Lyman alpha forest of quasar absorption is a tracer of much larger amounts of ionised hydrogen. The ionised component has yet to be detected directly, but is expected to…

Astrophysics · Physics 2009-11-11 Rupert A. C. Croft , A. J. Banday , Lars Hernquist

(abridged) We present an effective implementation of analytical calculations of the Lyalpha opacity distribution of the Intergalactic Medium (IGM) along multiple lines of sight (LOS) to distant quasars in a cosmological setting. This method…

Astrophysics · Physics 2009-11-06 M. Viel , S. Matarrese , H. J. Mo , M. G. Haehnelt , Tom Theuns

We present a method to make predictions with sets of correlated data values, in this case QSO flux spectra. We predict the continuum in the Lyman-Alpha forest of a QSO, from 1020 -- 1216 A, using the spectrum of that QSO from 1216 -- 1600 A…

Astrophysics · Physics 2009-11-10 Nao Suzuki , David Tytler , David Kirkman , John M. O'Meara , Dan Lubin

We analyze the SDSS Ly-alpha forest P_F(k,z) measurement to determine the linear theory power spectrum. Our analysis is based on fully hydrodynamic simulations, extended using hydro-PM simulations. We account for the effect of absorbers…

We investigate correlations between the long wavelength fluctuations and the small scale power in the Lyman alpha forest. We show that such correlations can be used to discriminate between fluctuations induced by large scale structure and…

Astrophysics · Physics 2009-10-31 Matias Zaldarriaga , Uros Seljak , Lam Hui

The correlation between Lyman-alpha absorption in the spectra of quasar pairs can be used to measure the transverse distance scale at z~2, which is sensitive to the cosmological constant (Omega_Lambda) or other forms of vacuum energy. Using…

Astrophysics · Physics 2009-11-07 Patrick McDonald

We measure the matter power spectrum from the Lyman-alpha forest of 31 quasar spectra spanning the redshift range of 1.6-3.6. The optical depth, $\tau$, for absorption of the intergalactic medium is obtained from the flux using the…

Astrophysics · Physics 2009-11-11 S. Zaroubi , M. Viel , A. Nusser , M. Haehnelt , T. -S. Kim

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 use the redshift evolution of the lyman-alpha forest mean transmitted flux at z>2.5 to infer the evolution of the intensity of the ionizing background, using theoretical predictions for the density distribution of the intergalactic gas…

Astrophysics · Physics 2009-10-31 Patrick McDonald , Jordi Miralda-Escude

It has been realised only recently that TeV emission from blazars can significantly heat the intergalactic medium (IGM) by pair-producing high-energy electrons and positrons, which in turn excite vigorous plasma instabilities, leading to a…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Ewald Puchwein , Christoph Pfrommer , Volker Springel , Avery E. Broderick , Philip Chang

We directly measure the evolution of the intergalactic Lya effective optical depth, tau_eff, over the redshift range 2<z<4.2 from a sample of 86 high-resolution, high-signal-to-noise quasar spectra obtained with the ESI and HIRES…

Astrophysics · Physics 2009-11-13 C. -A. Faucher-Giguere , J. X. Prochaska , A. Lidz , L. Hernquist , M. Zaldarriaga

We investigate a method to determine the temperature-density relation of the intergalactic medium (IGM) at z~2-4 using quasar absorption line systems. Using a simple model combined with numerical simulations we show that there is a lower…

Astrophysics · Physics 2009-10-31 Greg L. Bryan , Marie E. Machacek

We reassess constraints on the cosmological baryon density from observations of the mean decrement and power spectrum of the Lyman-alpha forest, taking into account uncertainties in all free parameters in the simplest gravitational…

Astrophysics · Physics 2009-11-06 Lam Hui , Zoltan Haiman , Matias Zaldarriaga , Tal Alexander

The Lyman-alpha forest is a portion of the observed light spectrum of distant galactic nuclei which allows us to probe remote regions of the Universe that are otherwise inaccessible. The observed Lyman-alpha forest of a quasar light…

We present new measurements of the mean transmitted flux in the hydrogen Ly$\rm \alpha$ and a relative transmitted flux measurement in Ly$\rm \beta$ using 27,008 quasar spectra from the Fourteenth Data Release (DR14) of the Extended Baryon…

Astrophysics of Galaxies · Physics 2024-06-18 Jiani Ding , Piero Madau , J. Xavier Prochaska

Numerical simulations indicate that the smooth, photoionized intergalactic medium (IGM) responsible for the low column density Lyman-alpha forest follows a well defined temperature-density relation. We show that such an equation of state…

Astrophysics · Physics 2007-05-23 Joop Schaye , Tom Theuns , Anthony Leonard , George Efstathiou

The distribution of diffuse gas in the intergalactic medium (IGM) imprints a series of hydrogen absorption lines on the spectra of distant background quasars known as the Lyman-$\alpha$ forest. Cosmological hydrodynamical simulations…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-31 Alberto Rorai , Joseph F. Hennawi , Jose Oñorbe , Martin White , J. Xavier Prochaska , Girish Kulkarni , Michael Walther , Zarija Lukić , Khee-Gan Lee