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We publicly release a new sample of $34$ medium resolution quasar spectra at $5.77\leq z_{\rm em}\leq6.54$ observed with the Echellette Spectrograph and Imager (ESI) on the Keck telescope. This quasar sample represents an ideal laboratory…

Astrophysics of Galaxies · Physics 2018-09-05 Anna-Christina Eilers , Frederick B. Davies , Joseph F. Hennawi

We directly measure the evolution of the intergalactic Lyman-alpha 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 Keck/ESI,…

Astrophysics · Physics 2010-11-11 C. -A. Faucher-Giguere , J. X. Prochaska , A. Lidz , L. Hernquist , M. Zaldarriaga

We calculate the intergalactic photon density as a function of both energy and redshift for 0 < z < 6 for photon energies from .003 eV to the Lyman limit cutoff at 13.6 eV in a Lambda-CDM universe with $\Omega_{\Lambda} = 0.7$ and…

Astrophysics · Physics 2010-11-11 F. W. Stecker , M. A. Malkan , S. T. Scully

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 present measurements of the mean and scatter of the IGM Lyman-{\alpha} opacity at 4.9 < z < 6.1 along the lines of sight of 62 quasars at z > 5.7, the largest sample assembled at these redshifts to date by a factor of two. The sample…

We report new measurements of the intergalactic medium (IGM) Ly$\alpha$ and Ly$\beta$ effective optical depth at $5.3<z<6.5$, using a new sample of quasar sightlines including 32 quasars at $6.308\le z\le7.00$. These quasars provide a large…

(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 use high quality echelle spectra of 24 QSOs to provide a calibrated measurement of the total amount of Lyman-alpha forest absorption (DA) over the redshift range 2.2 < z < 3.2. Our measurement of DA excludes absorption from metal lines…

We measure the intergalactic medium (IGM) opacity in the Ly$\alpha$ as well as in the Ly$\beta$ forest along $19$ quasar sightlines between $5.5\lesssim z_{\rm abs}\lesssim 6.1$, probing the end stages of the reionization epoch. Owing to…

Astrophysics of Galaxies · Physics 2019-08-14 Anna-Christina Eilers , Joseph F. Hennawi , Frederick B. Davies , Jose Oñorbe

We present a Bayesian inference on the neutral hydrogen fraction of the intergalactic medium (IGM), $x_{\textrm{HI}}$, at $z \sim$ 6-8 using the properties of Lyman break galaxies during the Epoch of Reionization. We use large samples of…

We identify a concordant model for the intergalactic medium (IGM) at redshift z=1.9 that uses popular values for cosmological and astrophysical parameters and accounts for all baryons with an uncertainty of 6%. We have measured the amount…

We present a new method to directly measure the opacity from HI Lyman limit (LL) absorption k_LL along quasar sightlines by the intergalactic medium (IGM). The approach analyzes the average (``stacked'') spectrum of an ensemble of quasars…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 J. Xavier Prochaska , Gabor Worseck , John M. O'Meara

We investigate the intrinsic opacity of high-redshift galaxies to outgoing ionising photons using high-quality photometry of a sample of 27 spectroscopically-identified galaxies of redshift 1.9<z<3.5 in the Hubble Deep Field. Our…

Astrophysics · Physics 2009-11-07 A. Fernandez-Soto , K. M. Lanzetta , H. -W. Chen

We present new high-precision measurements of the opacity of the intergalactic and circumgalactic medium (IGM, CGM) at <z>=2.4. Using Voigt profile fits to the full Lyman alpha and Lyman beta forests in 15 high-resolution high-S/N spectra…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Gwen C. Rudie , Charles C. Steidel , Alice E. Shapley , Max Pettini

The large opacity fluctuations in the $z > 5.5$ Ly$\alpha$ forest may indicate inhomogeneous progress of reionization. To explain the observed large scatter of the effective Ly$\alpha$ optical depth ($\tau_{\rm eff}$) of the intergalactic…

Quasar spectra provide a unique opportunity to investigate the intergalactic medium at high redshifts. The spectral analysis of the Ly$\alpha$ forest allows us to constrain the effective equation of state of the intergalactic medium and its…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-02 K N Telikova , S A Balashev , P S Shternin

We present an analysis of the Lyman alpha forests of five quasar spectra in the near UV. Properties of the intergalactic medium (IGM) at an intermediate redshift interval (0.9 < z < 1.9) are studied. The amount of baryons in the diffuse…

Astrophysics · Physics 2007-07-04 N. Prause , D. Reimers , C. Fechner , E. Janknecht

The distribution of neutral hydrogen in the intergalactic medium (IGM) is currently explored at low-z by means of UV spectroscopy of quasars. We propose an alternative approach based on UV colours of quasars as observed from GALEX surveys.…

Astrophysics of Galaxies · Physics 2019-11-05 J. -M. Deharveng , B. Milliard , C. Peroux , T. Small

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 present the Lyman-$\alpha$ (Ly$\alpha$) and ultraviolet (UV) luminosity function (LF), in bins of redshift, of quasars selected in the Physics of the Accelerating Universe Survey (PAUS). A sample of 915 objects was selected at…

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