1. 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

2. Process to date Jan 2015: AAS Jan community discussion
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

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

4. 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 ~ 1cm, 10hr, 8GHz
TB ~ 1cm, 15mas
Real line science begins at 15GHz

5. 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

6. 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

7. 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’

8. 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

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

10. 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

11. 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

12. 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

13. 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

14. 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

15. 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?

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

17. 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

18. 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

19. 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?