12 citations · 23 across the 5 of their papers we have counts for
5 papers
Softening of the Metagalactic Ionizing Background from Internal He II Absorption in Quasars
Michael Shull, Charles Danforth
Quasars and active galactic nuclei (AGN) are significant contributors to the metagalactic ionizing background at redshifts z < 3. Recent HST/COS composite spectra of AGN find a har…
Unique Astrophysics in the Lyman Ultraviolet
Jason Tumlinson, Alessandra Aloisi, Gerard Kriss +24
There is unique and groundbreaking science to be done with a new generation of UV spectrographs that cover wavelengths in the "Lyman Ultraviolet" (LUV; 912 - 1216 Ang). There is no…
Critical Star-Formation Rates for Reionization: Full Reionization occurs at z = 7
Michael Shull, Anthony Harness, Michele Trenti +1
We assess the probable redshift (z_rei ~ 7) for full reionization of the intergalactic medium (IGM) using a prescription for the co-moving star-formation-rate (SFR) density (rho_SF…
Optical Depth of the Cosmic Microwave Background and Reionization of the Intergalactic Medium
Michael Shull, Aparna Venkatesan
We examine the constraints on the epoch of reionization (redshift z_r) set by recent WMAP-3 observations of tau_e = 0.09 +/- 0.03, the electron-scattering optical depth of the cosm…
FUSE observations of the HeII Lyman alpha forest towards HS1700+6416
D. Reimers, C. Fechner, G. Kriss +5
We present FUSE observations of the HeII Lyman alpha forest in the redshift range 2.3 < z < 2.7 towards HS1700+6416. Between October 2002 and February 2003, the brightness of the Q…