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We present high S/N echelle spectra of the recently discovered ultraluminous QSO APM 08279+5255 and use these data to re-examine the abundance of Carbon in Ly alpha forest clouds. In agreement with previous work, we find that approximately…

The velocity offset of Ly$\alpha$ emission from a galaxy's systemic redshift is an excellent tracer of conditions that enable the escape of Ly$\alpha$ photons from the galaxy, and potentially hydrogen ionizing Lyman continuum photons.…

Astrophysics of Galaxies · Physics 2024-04-23 Mark H Cunningham , Aayush Saxena , Richard S Ellis , Laura Pentricci

Super-resolution is an ill-posed problem, where a ground-truth high-resolution image represents only one possibility in the space of plausible solutions. Yet, the dominant paradigm is to employ pixel-wise losses, such as L_1, which drive…

Computer Vision and Pattern Recognition · Computer Science 2021-11-08 Andreas Lugmayr , Martin Danelljan , Fisher Yu , Luc Van Gool , Radu Timofte

We present the results of 300 pc resolution ALMA imaging of the [OIII] 88 $\mu$m line and dust continuum emission from a $z = 8.312$ Lyman break galaxy MACS0416_Y1. The velocity-integrated [OIII] emission has three peaks which are likely…

Improved measurement of the Cosmic Microwave Background polarization from Planck allows a detailed study of reionization beyond the average optical depth. The lower value of the optical depth disfavours an early onset and an early…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-13 Daniela Paoletti , Dhiraj Kumar Hazra , Fabio Finelli , George F. Smoot

Knowledge of the evolution of the low column density end of the Ly alpha forest (12.8 < log N_HI < 16.0 cm^-2) can provide substantial insight for models of structure formation and studies of the evolution of the ionizing background. Here…

Astrophysics · Physics 2007-05-23 Esther M. Hu

[abbreviated] We present a census of Ly\alpha\ emission at $z\gtrsim7$ utilizing deep near infrared HST grism spectroscopy from the first six completed clusters of the Grism Lens-Amplified Survey from Space (GLASS). In 24/159…

The effective optical depth in the Ly-alpha forest region of 1061 low-resolution QSO spectra drawn from the SDSS database decreases with decreasing redshift over the range 2.5 < z < 4. Although the evolution is relatively smooth, tau_eff ~…

The first observations of the recently completed Wisconsin H-Alpha Mapper (WHAM) facility include a study of emission lines from high velocity clouds in the M, A, and C complexes, with most of the observations on the M I cloud. We present…

Astrophysics · Physics 2009-10-30 S. L. Tufte , R. J. Reynolds , L. M. Haffner

Charge-Coupled Device (CCD) detectors, widely used to obtain digital imaging, can be damaged by high energy radiation. Degraded images appear blurred, because of an effect known as Charge Transfer Inefficiency (CTI), which trails bright…

Instrumentation and Methods for Astrophysics · Physics 2014-03-05 Richard Massey , Tim Schrabback , Oliver Cordes , Ole Marggraf , Holger Israel , Lance Miller , David Hall , Mark Cropper , Thibaut Prod'homme , Sami-Matias Niemi

Our goal in this paper is to test some popular dark matter models by Ly-alpha forest in QSO spectra. Recent observations of the size and velocity of Ly-alpha forest clouds have indicated that the Ly-alpha absorption is probably not given by…

Astrophysics · Physics 2009-10-28 Hongguang BI , Jian GE , Li-Zhi FANG

Interpretation of He II Ly{\alpha} absorption spectra after the epoch of He II reionization requires knowledge of the He II ionizing background. While past work has modelled the evolution of the average background, the standard cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Frederick B. Davies , Steven R. Furlanetto

Optical emission lines provide an important new window on the HVCs. Recent studies of the H-alpha line reveal that ionized gas is pervasively associated with the neutral hydrogen in HVCs. The Wisconsin H-Alpha Mapper (WHAM) instrument has…

Astrophysics · Physics 2007-05-23 S. L. Tufte , R. J. Reynolds , L. M. Haffner

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

Hydrodynamic cosmological simulations predict that the average opacity of the Ly-alpha forest should increase in the neighborhood of galaxies because galaxies form in dense environments. Recent observations (Adelberger et al. 2002) confirm…

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

We present a method for including steady-state gas flows in the plasma physics code Cloudy, which was previously restricted to modeling static configurations. The numerical algorithms are described in detail, together with an example…

Astrophysics · Physics 2009-11-10 William J. Henney , S. Jane Arthur , Robin J. R. Williams , Gary J. Ferland

At redshifts beyond z>6, as the mean fraction of neutral hydrogen x_HI in the intergalactic medium (IGM) increases, the line flux of Lyman alpha (Lya) emitters can be significantly suppressed, which can result in a decrease in the observed…

Astrophysics · Physics 2009-11-10 Zoltan Haiman , Renyue Cen

Observations of high-redshift Ly-alpha sources are a major tool for studying the high-redshift Universe. We discuss the effect of the reionizing intergalactic medium on the observability of Ly-alpha sources based on large simulations of…

Astrophysics · Physics 2009-11-13 Ilian T. Iliev , Paul R. Shapiro , Patrick McDonald , Garrelt Mellema , Ue-Li Pen

(ABRIDGED)The Ly$\alpha$ clouds at low redshifts (z < 1.7)observed by HST showed us two unexpected features: Lanzetta et.al.establised the association between Ly$\alpha$ clouds and galaxies, and Ulmer pointed out the strong clustering of…

Astrophysics · Physics 2016-08-30 Keiko Miyahata , Satoru Ikeuchi

Spatially extended halos of H I Ly$\alpha$ emission are now ubiquitously found around high-redshift star-forming galaxies. But our understanding of the nature and powering mechanisms of these halos is still hampered by the complex radiative…