The Alice spectrograph on New Horizons performed several far-ultraviolet (FUV) airglow observations during the July 2015 flyby of Pluto. One these observations, named PColor2, was a short (226 s) scan across dayside disk Pluto from range ∼34,000 km, at about 40 minutes prior to closest approach. brightest observed FUV signal is Lyman alpha (Lyα) emission line atomic hydrogen, which arises prima...

Aims. The development of a general code for 3D Lyα radiation transfer in galaxies to understand the diversity of Lyα line profiles observed in star forming galaxies and related objects. Methods. Using a Monte Carlo technique we have developed a 3D Lyα radiation transfer code allowing for prescribed arbitrary hydrogen density, ionisation, temperature structures, and dust distributions, and arbit...

We have discovered a ≈45 kpc Lyα nebula (or Lyα “blob”) at z ≈ 1.67 which exhibits strong, spatially-extended He ii emission and very weak C iv and C iii] emission. This is the first spatiallyextended Lyα+He ii emitter observed and the lowest redshift Lyα blob yet found. Strong Lyα and He iiλ1640 emission in the absence of metal lines has been proposed as a unique observational signature of pri...

Intergalactic Lyα opacity suggests that H I was reionized at z ≈ 6, while He II reionization was delayed to z ≈ 3. Both epochs are in conflict with inferences from CMB optical depth (WMAP) which suggest early reionization at z = 10−20. One of the major contributions of FUSE to cosmological studies has been the detection of He II Lyα (“Gunn-Peterson”) absorption in the spectra of AGN at redshift...

Observations of the Lyα forest at z ∼ 3 reveal a metallicity Z ∼ 10 −2 Z ⊙. The high-redshift supernovae that polluted the IGM also accelerated relativistic electrons. Since the energy density of the CMB ∝ (1 + z) 4 , at high redshift these electrons cool via inverse Compton scattering. Thus, the first star clusters emit X-rays. Unlike stellar UV ionizing photons, these X-rays can escape easily...

We present new statistical study on the origin of Lyα absorption systems that are detected in QSO fields. The primary objective is to investigate environmental dependence of the relationship between galaxies and Lyα absorption systems. We find that galaxies exhibit no environmental dependence in giving rise to Lyα absorbers in their halos. Conversely, Lyα absorbers do not exhibit preference as ...

We explore the impact of spatial fluctuations in the intergalactic medium (IGM) temperature on the Lyα forest flux power spectrum near z ∼ 3. We develop a semi-analytic model to examine temperature fluctuations resulting from inhomogeneous HI and incomplete HeII reionizations. There are two main motivations for this investigation. First, detection of these fluctuations might provide insight int...

Evidence is presented that the damped Lyα absorption systems are the high-redshift (z > 3) progenitors of galaxy disks. I discuss kinematic evidence that the damped Lyα systems are rotating disks. I also discuss implications of the lack of metal-poor damped Lyα systems with line width ∆v > 100 km s. I then present new evidence stemming from correlations between element-abundance ratios and [Fe/...

We present a new theoretical model for the luminosity functions (LFs) of Lyα emitting galaxies in the framework of hierarchical galaxy formation. We extend a semi-analytic model of galaxy formation that reproduces a number of observations for local galaxies, without changing the original model parameters but introducing a physically-motivated modelling to describe the escape fraction of Lyα pho...

The absorption system at z = 3.572 towards Q1937–1009 provides the best extragalactic measurement of the atomic deuterium to hydrogen ratio, D/H. We have obtained a new low-resolution, high signal-to-noise ratio (SNR) Keck spectrum to re-measure the total neutral hydrogen column density N(H I) using the amount of Lyman continuum absorption. We develop a new method to directly determine the intr...