HI imaging the low red-shift cosmic web

HI Imaging the Low Red-shift Cosmic Web

Only in recent years has the realization emerged that galaxies do not dominate the universal baryon budget but are merely the brightest pearls of an underlying Cosmic Web. Although the gas in these inter-galactic filaments is moderately to highly ionized, QSO absorption lines have shown that the surface area increases dramatically in going down to lower HI column densities. The first image of t...

Imaging the Low Red - shift Cosmic Web

The first image of a Cosmic Web, Lyman Limit System has just been made in HI emission within the Local Group filament connecting M31 and M33. The corresponding HI distribution function is in very good agreement with that of the QSO absorption lines, confirming the 30-fold increase in surface area expected between 10 cm and 10 cm. The critical observational challenge is crossing the “HI desert”,...

Future Possibilities for Detecting Hi at High Red-shift

High-resolution imaging of the cosmic mass distribution from gravitational lensing of pregalactic HI

Low-frequency radio observations of neutral hydrogen during and before the epoch of cosmic reionization will provide ∼ 1000 quasi-independent source planes, each of precisely known redshift, if a resolution of ∼ 1 arcminutes or better can be attained. These planes can be used to reconstruct the projected mass distribution of foreground material. Structure in these source planes is linear and ga...

Exploring the magnetized cosmic web through low frequency radio emission

Recent improvements in the capabilities of low frequency radio telescopes provide a unique opportunity to study thermal and non-thermal properties of the cosmic web. We argue that the diffuse, polarized emission from giant radio relics traces structure formation shock waves and illuminates the large-scale magnetic field. To show this, we model the population of shockaccelerated relativistic ele...