[Paper Review] Science with an ngVLA: The ngVLA Science Case and Associated Science Requirements

E. J. Murphy, Alberto D. Bolatto+23 more|arXiv (Cornell University)|Oct 15, 2018

Distributed and Parallel Computing Systems1 references42 citations

TL;DR

This paper presents the ngVLA science case and the five Key Science Goals (KSGs) with associated technical requirements to guide a next-generation radio interferometer with 1.2–116 GHz coverage, >10x VLA/ALMA sensitivity, and North American baselines.

ABSTRACT

The science case and associated science requirements for a next-generation Very Large Array (ngVLA) are described, highlighting the five key science goals developed out of a community-driven vision of the highest scientific priorities in the next decade. Building on the superb cm observing conditions and existing infrastructure of the VLA site in the U.S. Southwest, the ngVLA is envisaged to be an interferometric array with more than 10 times the sensitivity and spatial resolution of the current VLA and ALMA, operating at frequencies spanning $\sim1.2 - 116$\,GHz with extended baselines reaching across North America. The ngVLA will be optimized for observations at wavelengths between the exquisite performance of ALMA at submm wavelengths, and the future SKA-1 at decimeter to meter wavelengths, thus lending itself to be highly complementary with these facilities. The ngVLA will be the only facility in the world that can tackle a broad range of outstanding scientific questions in modern astronomy by simultaneously delivering the capability to: (1) unveil the formation of Solar System analogues; (2) probe the initial conditions for planetary systems and life with astrochemistry; (3) characterize the assembly, structure, and evolution of galaxies from the first billion years to the present; (4) use pulsars in the Galactic center as fundamental tests of gravity; and (5) understand the formation and evolution of stellar and supermassive blackholes in the era of multi-messenger astronomy.

Motivation & Objective

• Motivate a next-generation radio/mm facility with unprecedented sensitivity and resolution beyond the VLA and ALMA.
• Define five Key Science Goals (KSGs) that structure the ngVLA science program.
• Specify the general science requirements that drive the ngVLA reference design.
• Demonstrate complementarities with other facilities and the multi-messenger astronomy era.
• Highlight community-driven processes that shaped the ngVLA mission and capabilities.

Proposed method

• Aggregate and synthesize community science cases (over 80 use cases) solicited by NRAO.
• Identify criteria for selecting KSGs based on scientific importance, ngVLA-uniqueness, and cross-facility synergy.
• Translate KSGs into quantitative requirements for sensitivity, resolution, bandwidth, and survey speed to inform the ngVLA Reference Design.

Experimental results

Research questions

• RQ1 What are the most compelling cm–mm wavelength science goals that an ngVLA must address?
• RQ2 How can ngVLA capabilities be optimally shaped to enable planet formation, astrochemistry, galaxy evolution, pulsar gravity tests, and black hole studies?
• RQ3 What are the essential technical requirements (sensitivity, resolution, bandwidth, dynamic range) to realize the five KSGs?
• RQ4 How should ngVLA complement existing/planned facilities and participate in multi-messenger astronomy?
• RQ5 What process ensures community consensus on ngVLA’s science mission and instrument specifications?

Key findings

• The ngVLA is envisioned to deliver roughly 10x the sensitivity and angular resolution of the current VLA and ALMA.
• The frequency coverage spans approximately 1.2–116 GHz with up to 20 GHz instantaneous bandwidth.
• Five Key Science Goals were identified to drive the Reference Design and science requirements.
• The KSGs emphasize planet formation, astrochemistry, galaxy evolution, Galactic Center pulsar gravity tests, and black hole formation/evolution in a multi-messenger era.
• The ngVLA design prioritizes a compact core, extended baselines across North America, and broad wide-band continuum and spectral capabilities to enable diverse science across time-domain, morphology, and high-resolution imaging.