Speaker
paul oconnor
(Brookhaven National Laboratory)
Description
In the next decade several flagship Dark Energy surveys (DESI, EUCLID, LSST) will be nearing completion and interest in a next-generation experiment is increasing. One promising new technique is intensity mapping (IM), which unlike prior surveys uses the redshifted 21-cm emission from neutral hydrogen in galaxies to trace Large Scale Structure in three dimensions. The systematics associated with radio measurements will be highly complementary to those of optical galaxy and CMB surveys, leading to tighter constraints on the standard cosmological parameters characterizing the expansion history and growth of structure. More importantly, the IM approach offers the possibility to probe the largely unexplored Universe in the redshift range 2.5 < *z* < 6, where signatures of modified gravity, early dark energy, and inflation may be detected or constrained. IM surveys thus have the potential to provide evidence of new physics beyond the concordance $\Lambda$CDM cosmological model.
Intensity mapping uses mass-producible receivers with no moving parts or exotic semi/superconducting components, and piggybacks on the explosive growth of commodity hardware used for wireless telecommunication and high-throughput data processing. With these cost-effective technologies, it becomes possible to to envision building a large interferometric array with massive collecting area, millions of redundant baselines, and raw data rates up to hundreds of Tbit/s. Critical technologies required for such an instrument include triggerless ("streaming") data acquisition, ultra-high bandwidth data links, use of heterogeneous real-time processing (ASIC, FPGA, GPU, CPU), and sub-ps timing distribution, all of which can leverage from current and upcoming research in the other OHEP frontier areas.
This presentation will place IM in context with other survey modalities and provide an overview of several current and proposed experiments.
Summary
Intensity mapping using the redshifted 21-cm emission from neutral hydrogen in galaxies is a new survey technique for studying dark energy and inflation. It complements optical and CMB surveys while opening a window into the largely unexplored universe at 2.5 < z < 6, where signatures of new physics beyond the concordance $\Lambda$CDM cosmological model may be detected. Cost-effective and scalable construction is enabled by piggybacking on trends in software-defined radio and commodity data processing.
Primary author
paul oconnor
(Brookhaven National Laboratory)
