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

• Resolution ~ 15mas @ 1cm (180km)

Killer GapThermal imaging on mas scales at λ ~ 0.3cm to 3cm

1AU @ 140pc

B. Kent

• Sensitivity ~ 200nJy @ 1cm, 10hr, 8GHz

• TB ~ 1K @ 1cm, 15mas

• Real line science begins at 15GHz

Killer GapThermal 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

Killer GapThermal imaging on mas scales at λ ~ 0.3cm to 3cm

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

τ = 1 at λ < 1mm τ = 1 at λ > 1cm

ngVLA zone

100AU

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

• 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

• 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

Glycine; Codella ea. 2014

SKA

ngVLA

SF Law

Galaxy assembly (Casey + SWG3): Dense gas history of Universe

Missing half of galaxy formation

SFR

Gas mass (LCO 1-0)

Gas mass calibrated w. CO 1-0 Total gas mass w/o excitation

uncertainty Dense gas tracers associated

w. SF cores: HCN, HCO+

Low order CO: key total cool gas mass tracer

ngVLA ‘sweet spot’

SKA

10x uncertainty

Galaxy assembly

CO emission from typical star forming, ‘main sequence’ galaxies at high z

z=5, 30 Mo/yr , 1hr, 300 km/s

Number of CO detections per hour

• JVLA ~ 1, Mgas > 1010 Mo

• ngVLA: tens to hundreds, Mgas > 1010 Mo

JVLA

ngVLA

CO 1-0 CO 3-2z ~ 3

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)

Narayanan

ncr > 104 cm-3

ncr ~ 103 cm-3

Galaxy eco-systems (Murphy + SWG2)

Milky Way and the nearby Universe

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

ngVLA

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

Snell ea

Schinerer 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)

Time domain: phenomena peaking @ 0.3cm to 3cm

FRBs, TDEs Solar bursts Radio photospheres Novae:

‘peeling onion’ Radio counterparts to GW events

10GHz

1GHz

GBR/TDE: late time jet shock

15GHz

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

Physics, cosmology, time domain

100ms solar flaresMpc-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?