Science with a Next Generation Very Large Array Notional Specifications Physical area 6 x VLA, but higher efficiency > 30 GHz Frequency range: 1 – 50, 70 – 115 GHz Configuration: 50% to few km; 40% to 200km; 10% to 3000km

Process to date Jan 2015: AAS Jan community discussion https://science.nrao.edu/science/meetings/2015/aas225/next-gen-vla/ngvla March 2015: Science working group white papers Cradle of Life (Isella, Moullet, Hull) Galaxy ecosystems (Murphy, Leroy) Galaxy assembly (Lacy, Casey, Hodge) Time domain, Cosmology, Physics (Bower, Demorest) April 2015: Pasadena technology meeting

Thermal imaging on mas scales at λ ~ 0.3cm to 3cm Killer Gap Thermal imaging on mas scales at λ ~ 0.3cm to 3cm 1AU @ 140pc B. Kent Resolution ~ 15mas @ 1cm (180km)

Thermal imaging on mas scales at λ ~ 0.3cm to 3cm Killer Gap Thermal imaging on mas scales at λ ~ 0.3cm to 3cm Sensitivity ~ 200nJy @ 1cm, 10hr, 8GHz TB ~ 1K @ 1cm, 15mas Real line science begins at 15GHz

Thermal imaging on mas scales at λ ~ 0.3cm to 3cm Killer Gap Thermal imaging on mas scales at λ ~ 0.3cm to 3cm Many other parameters: FoV, Bandwidth, Tsys, RFI occupation, UV coverage (dynamic range, surface brightness), Atmospheric opacity and Phase stability, Pointing… Relative metrics depend on science application

Grain size stratification at 0.3cm to 3cm: τ = 1 at λ < 1mm τ = 1 at λ > 1cm Cradle of life: Terrestrial planet formation imager (Isella et al. SWG1) See through dust to pebbles: inner few AU disk optically thick in mm/submm Grain size stratification at 0.3cm to 3cm: Poorly understood transition from dust to planetesimals Annual changes 100AU ngVLA zone

Terrestrial planet formation imager Circumplanetary disks: imaging accretion on to planets? Imaging Earth-like planets in habitable zone is top priority in OIR in the next decade: “The vision outlined in this report is for a 10–12 m segmented space telescope with exquisite sensitivity from the UV through the NIR, and superb image and wavefront quality. This observatory would allow direct detection of Earth-like planets and characterization of their atmospheres, along with a rich program of astrophysics covering every stage of the pathway from cosmic birth to living earths.” AURA report ‘Future of UVOIR Space Astronomy’

Cradle of Life: origin stars, planets, life Glycine; Codella ea. 2014 SKA Chemistry in PP disks on AU-scales Complex organics: ice chemistry in cold regions Pre-biotic molecules: rich spectra in 0.3cm to 3cm regime Ammonia and water ngVLA Star formation Origin of stellar multiplicity High mass star formation: resolving accretion in dust-obscured early phases Peer deep into planetary atmospheres, comets, asteroids, sub-surface radar

Galaxy assembly (Casey + SWG3): Dense gas history of Universe Missing half of galaxy formation SF Law SFR Gas mass (LCO 1-0)

ngVLA ‘sweet spot’ Low order CO: key total cool gas mass tracer Gas mass calibrated w. CO 1-0 Total gas mass w/o excitation uncertainty Dense gas tracers associated w. SF cores: HCN, HCO+ 10x uncertainty ngVLA ‘sweet spot’ SKA

z=5, 30 Mo/yr , 1hr, 300 km/s Galaxy assembly CO emission from typical star forming, ‘main sequence’ galaxies at high z ngVLA Number of CO detections per hour JVLA ~ 1, Mgas > 1010 Mo ngVLA: tens to hundreds, Mgas > 1010 Mo JVLA

Galaxy assembly: Imaging on 1 kpc-scales Low order: distributed gas dynamics, not just dense cores w. ALMA dust imaging: resolved star formation laws (gas – SFR surface density) CO 1-0 CO 3-2 z ~ 3 ncr > 104 cm-3 ncr ~ 103 cm-3 Narayanan

Galaxy eco-systems (Murphy + SWG2) Milky Way and the nearby Universe ngVLA Broad-Band Continuum Imaging Simultaneously capture multiple radio emission mechanisms: synchrotron, free-free, cold (spinning?) dust, SZ effect Independent estimates of SFR Physics of cosmic rays, ionized gas, dust, and hot gas around galaxies

Spectral Line Mapping @ 10GHz to 100GHz on pc-scales Map cool ISM 10x faster than ALMA First order transitions of major astrochemical tracers Baryon cycle: following life cycle of gas to stars to gas Schinerer ea. Snell ea

Galaxy eco-systems: Milky Way and the nearby Universe VLBI uas astrometry Complete view of the large scale structure of MW 3D imaging of dynamics of local group: dark matter, real-time cosmology Not strongly dynamic range limited: 10% on long baselines?

Physics, cosmology, time domain (Bower et al. SWG4) GBR/TDE: late time jet shock 15GHz Time domain: phenomena peaking @ 0.3cm to 3cm FRBs, TDEs Solar bursts Radio photospheres Novae: ‘peeling onion’ Radio counterparts to GW events 10GHz 1GHz

The plasma Universe: solar flares to galaxy clusters Physics, cosmology, time domain The plasma Universe: solar flares to galaxy clusters Magnetic reconnection vs. shock acceleration: broad band phenomena Stellar photospheres, winds, mass loss Stellar-exoplanet magnetospheric interactions 100ms solar flares Mpc-scale cluster emission

Physics, cosmology, time domain Megamasers and Ho: double precision cosmology Evolution of fundamental constants using radio absorption lines: best lines in K through Q band CO intensity mapping: BAO in matter dominated era (z>2) Galactic center pulsars

Killer gap: where ngVLA excels wrt SKA1 and ALMA Imaging terrestrial zone planet formation Dense gas history of Universe Pre-biotic molecules Maser, CO cosmology Next steps Quantify! physical modeling + configurations + simulations Focused workshop on science case, calculations Call for community white papers?