science with a next generation very large array notional specifications physical area 6 x vla, but...
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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?