Science
Futures II will focus on the four broad areas of RMS community scientific interest and opportunity that emerged from Futures I. Each Futures II focus area will explore the Flagship and Small/Midscale instrument initiatives required for transformational scientific progress. Flagship initiatives are major investments with broad community benefit and support that require funding by or on a scale comparable to the National Science Foundation (NSF) – Major Research Equipment and Facility Construction program. Small/Midscale initiatives are significant investments that might be funded via the NSF Mid-Scale Initiative Program, such as experiments emerging from smaller groups and collaborations.
Futures II Focus Area: Cosmic Microwave Background
Zeeshan Ahmed, Chair
The scientific case is being developed for a next generation ground-based cosmic microwave background (CMB) experiment, CMB-S4, consisting of dedicated telescopes at the South Pole, the high Chilean Atacama plateau, and possibly a northern hemisphere site, all equipped with new superconducting cameras that will provide a dramatic leap forward in cosmological studies, crossing critical thresholds in testing inflation, the number and masses of the neutrinos or the existence of other ‘dark radiation’, providing precise constraints on the nature of dark energy, and testing general relativity on large scales.
Futures II Focus Area: Next Generation Very Large Array
Eric Murphy (NRAO), Chair
Inspired by dramatic discoveries from the Jansky Very Large Array (VLA) and the Atacama Large Millimeter/submillimeter Array (ALMA), the community has initiated discussion of a future large area radio array optimized for imaging of thermal emission to milli-arcsecond scales that will open new discovery space from proto-planetary disks to distant galaxies. This next generation Very Large Array (ngVLA) is currently envisioned to include: (a) ~10x/30x the effective collecting area of the VLA/ALMA; (b) frequency coverage spanning 1.2 – 116 GHz; (c) interferometric baselines up to 300 km to achieve milli-arcsecond resolution, with consideration for longer baselines and Very Long Baseline Interferometry; and (d) a dense antenna core on km-scales providing high surface brightness imaging.
Futures II Focus Area: Hydrogen Epoch of Reionization Array (HERA)
Aaron Parsons (UC, Berkeley), Chair
New instruments dedicated to observing the large-scale structure of the Universe during and prior to the epoch of reionization are being proposed that incorporate the lessons learned from the Murchison Widefield Array and the Precision Array for Probing the Epoch of Reionization. Cosmic reionization corresponds to the epoch when the neutral intergalactic medium is reionized by the first luminous objects. Probing this last unexplored phase of cosmic evolution offers extraordinary discovery potential for the field of cosmic structure formation. The substantially larger collecting area of the proposed second and third-generation HERA instruments would yield an order-of-magnitude or more sensitivity, be capable of robust statistical characterization, and yield the first images of large-scale neutral hydrogen structure.
Futures II Focus Area: Pulsars & Transients
Chair David Kaplan
The North American NanoHertz Observatory for Gravitational Waves and the International Pulsar Timing Array are monitoring a set of pulsars that form a Galactic scale gravitational-wave observatory and offer the potential to observe long-period gravitational waves via their effects on pulse light-travel times. These and other instruments will also continue to use pulsars to further explore the physics of extreme environments. Known radio transients include stellar flares, pulsars, and gamma-ray burst afterglows. Hypothesized classes of radio transients may enable transformational exploration of known phenomena – extrasolar planets emitting Jovian-like radio bursts and giant-pulse emitting pulsars in other galaxies – as well as the more exotic, such as prompt emission from gamma-ray bursts and evaporating black holes. New instruments and facilities are envisioned that combine the wide fields-of-view and wavelength agility required to transform our ability to study the Universe via radio transients.
