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High Redshift Metals I.: The Decline of C IV at z > 5.3
George D. Becker, Michael Rauch, Wallace L. W. Sargent
We present the results from our search for C IV in the intergalactic medium at redshifts z=5.3-6.0. We have observed four z~6 QSOs with Keck/NIRSPEC in echelle mode. The data are t…
A Population of Faint Extended Line Emitters and the Host Galaxies of Optically Thick QSO Absorption Systems
Michael Rauch, Martin Haehnelt, Andrew Bunker +10
We have conducted a long slit search for low surface brightness Lyman-alpha emitters at redshift 2.67 < z < 3.75. A 92 hour long exposure with VLT/FORS2 down to a 1-sigma surface b…
How cold is cold dark matter? Small scales constraints from the flux power spectrum of the high-redshift Lyman-alpha forest
M. Viel, G. D. Becker, J. S. Bolton +3
We present constraints on the mass of warm dark matter (WDM) particles derived from the Lyman-alpha flux power spectrum of 55 high- resolution HIRES spectra at 2.0 < z < 6.4. From…
Galactic Wind Signatures around High Redshift Galaxies
Daisuke Kawata, Michael Rauch
We carry out cosmological chemodynamical simulations with different strengths of supernova (SN) feedback and study how galactic winds from star-forming galaxies affect the features…
The Evolution of Optical Depth in the Ly-alpha Forest: Evidence Against Reionization at z~6
George D. Becker, Michael Rauch, Wallace L. W. Sargent
We examine the evolution of the IGM Ly-alpha optical depth distribution using the transmitted flux probability distribution function (PDF) in a sample of 63 QSOs spanning absorptio…
A Spectacular Radio Flare from XRF 050416a at 40 days and Implications for the Nature of X-ray Flashes
A. M. Soderberg, E. Nakar, S. B. Cenko +26
We present detailed optical, near-infrared, and radio observations of the X-ray flash 050416a obtained with Palomar and Siding Springs Observatories as well as HST and the VLA, pla…
Discovery of excess O I absorption towards the z = 6.42 QSO SDSS J1148+5251
George D. Becker, Wallace L. W. Sargent, Michael Rauch +1
We present a search for O I in the spectra of nine 4.9 < z_qso < 6.4 QSOs taken with Keck/HIRES. We detect six systems with N(O I) > 10^13.7 cm^{-2} in the redshift intervals where…
The afterglow of GRB050709 and the nature of the short-hard gamma-ray bursts
D. B. Fox, D. A. Frail, P. A. Price +33
The final chapter in the long-standing mystery of the gamma-ray bursts (GRBs) centres on the origin of the short-hard class, suspected on theoretical grounds to result from the coa…
Expansion and Collapse in the Cosmic Web
Michael Rauch, George D. Becker, Matteo Viel +5
We study the kinematics of the gaseous cosmic web at high redshift with Lyman alpha forest absorption in multiple QSO sightlines. Using a simple analytic model and a cosmological h…
Observations of Chemically Enriched QSO Absorbers near z ~ 2.3 Galaxies: Galaxy-Formation Feedback Signatures in the IGM
Robert A. Simcoe, Wallace L. W. Sargent, Michael Rauch +1
We present a study of galaxies and intergalactic gas toward the z=2.73 quasar HS1700+6416, to explore the effects of galaxy formation feedback on the IGM. Our observations and ioni…
Tightening Constraints from the Lyman Alpha Forest with the Flux Probability Distribution Function
Adam Lidz, Katrin Heitmann, Lam Hui +3
The analysis of the Lyman-alpha forest of absorption lines in quasar spectra has emerged as a potentially powerful technique to constrain the linear matter power spectrum. In most…
An HST Study of the Supernovae Accompanying GRB 040924 and GRB 041006
A. M. Soderberg, S. R. Kulkarni, P. A. Price +23
We present the results from a {\it Hubble Space Telescope/ACS} study of the supernovae associated with gamma-ray bursts 040924 () and 041006 (). We find evidence th…
An HST Search for Supernovae Accompanying X-ray Flashes
A. M. Soderberg, S. R. Kulkarni, D. B. Fox +24
We present the results from an Hubble Space Telescope/ACS search for supernovae associated with X-ray flashes 020903, 040701, 040812 and 040916. We find strong evidence that XRF 02…
Abundance Profiles and Kinematics of Damped Lyman-alpha Absorbing Galaxies at z < 0.65
Hsiao-Wen Chen, Robert C. Kennicutt, Michael Rauch
We present a spectroscopic study of six damped Lya absorption (DLA) systems at z<0.65, based on moderate-to-high resolution spectra of the galaxies responsible for the absorbers. C…
Large-Scale Correlations in the Lyman-alpha Forest at z = 3-4
George D. Becker, Wallace L. W. Sargent, Michael Rauch
We present a study of the spatial coherence of the intergalactic medium toward two pairs of high-redshift quasars with moderate angular separations observed with Keck/ESI, Q1422+23…
The Distribution of Metallicity in the IGM at z~2.5: OVI and CIV Absorption in the Spectra of 7 QSOs
Robert A. Simcoe, Wallace L. W. Sargent, Michael Rauch
We present a direct measurement of the metallicity distribution function for the high redshift intergalactic medium. We determine the shape of this function using survival statisti…
Metallicity of the intergalactic medium using pixel statistics: III. Silicon
Anthony Aguirre, Joop Schaye, Tae-Sun Kim +3
(Modified) We study the abundance of silicon in the intergalactic medium by analyzing the statistics of SiIV, CIV, and HI pixel optical depths in a sample of 19 high-quality quasar…
Characterizing the Warm-Hot IGM at High Redshift: A High Resolution Survey for O VI at z = 2.5
Robert A. Simcoe, Wallace L. W. Sargent, Michael Rauch
We describe a survey for OVI absorption in the spectra of 5 high redshift quasars (2.2 < z < 2.8). We identify 12 cosmological systems, and 6 systems that are either ejected from t…
Small Scale Structure at High Redshift: IV. Low Ionization Gas Intersecting Three Lines of Sight to Q2237+0305
M. Rauch, W. L. W. Sargent, T. A. Barlow +1
We have obtained Keck HIRES spectra of three images of the gravitationally lensed QSO 2237+0305 to study low ionization absorption systems and their differences in terms of project…
Small Scale Structure at High Redshift: III. The Clumpiness of the Intergalactic Medium on Sub-kpc Scales
Michael Rauch, Wallace L. W. Sargent, Thomas A. Barlow +1
Spectra from the Keck HIRES instrument of the Lyman alpha forests in the lines of sight to the A and C components of the gravitationally lensed QSO Q1422+231 were used to investiga…
Small Scale Structure at High Redshift: II. Physical Properties of the CIV Absorbing Clouds
Michael Rauch, Wallace L. W. Sargent, Thomas A. Barlow
Keck HIRES spectra were obtained of the separate images of three gravitationally lensed QSOs (UM 673, Q1104-1804, and Q1422+2309). We studied the velocity and column density differ…
A Measurement of the Temperature-Density Relation in the Intergalactic Medium Using a New Lyman-alpha Absorption Line Fitting Method
Patrick McDonald, Jordi Miralda-Escude, Michael Rauch +3
The evolution of the temperature in the intergalactic medium is related to the reionization of hydrogen and helium, and has important consequences for our understanding of the Lya…
Constraining reionization using the thermal history of the baryons
Joop Schaye, Tom Theuns, Michael Rauch +2
The thermal evolution of the intergalactic medium (IGM) depends on the reionization history of the universe. Numerical simulations indicate that the low density IGM, which is respo…
The thermal history of the intergalactic medium
Joop Schaye, Tom Theuns, Michael Rauch +2
At redshifts z >~ 2, most of the baryons reside in the smooth intergalactic medium which is responsible for the low column density Lyman-alpha forest. This photoheated gas follows…