Science imperatives for 2020

1. NRAO Socorro Science Retreat Socorro, NM, April 10, 2008 Science imperatives for 2020 • I will not define the science imperatives for NRAO in the next decade. • I will present current landscape: science cases in radio, optical…, plus various committee reports. • Goal: Science-driven vision for (radio) astronomy in next decade. Where does NRAO fit? How do we approach DS2010? Chris Carilli NRAO

2. Documents considered • Historical perspective -- pre-2020 review • Reports: Decadal Survey (McKee/Taylor), Quarks-Cosmos • Science goals: EVLA, ALMA • Intermezzo: Major advances in astrophysics since DS2000/EVLA • Modern era -- post-2020 review • Science goals: SKA, JWST, TMT, LSST, Herschel, ConX • Reports: RMSPG, AUI-Futures (McCray), Chicago I,II,III • Science cases can be: • Facility based/Technology driven • Theme based • Question based • Project/experiment based

3. Historical perspective • DS2000 (McKee-Taylor) Facility based • Broad-brush document -- too much so, unrealistic costing? • EVLA, ALMA recommended highly • Recommended both User grants and development $$ • Quarks-to-Cosmos -- supplanted DS2000? Question based • What is dark matter? (HI studies) • What is dark energy? (HI surveys) • How did Universe begin? (CMB) • Did Einstein have last word on gravity? (Pulsars) • Neutrino mass and evolution? • Cosmic accelerators? (AGN/SNR) • Are protons stable? • New states of matter at high den/temp? (Neutron stars) • Are there extra dimensions? • How are elements Fe -- U formed? • Is new theory of matter/light needed at highest energies?

4. EVLA science case • Science theme based • The Magnetic Universe -- obvious radio forte • The Obscured Universe -- PPdisks, YSOs, QSO abs lines… • The Transient Universe -- GRBs, XRBs, Mdwarfs… • The Evolving Universe -- galaxy evolution • Question: was the science case generated before or after the technical case?

5. ALMA science: Project based • Image molecular gas in z~3 MW-mass galaxies => A/T (64x12m) • Image PP disks on AU scales => ~10km baselines @ submm • HST quality imaging => # ant, ACA + TP • Actively involved/energized User community • Continuous refinement of ALMA science case, enabled by, but not dictated by, executives • ASAC + regional SACs: eg. organized the DRSP = observing proposals for ALMA from community to gauge ‘demand’ and prioritize use cases • Annual regional topical science meetings • Regular international ‘love fests’

6. Advances in modern astrophysics since DS00 and EVLA • Precision cosmology: few % knowledge of age, mass-energy content of Universe • Probing epoch of first light (cosmic reionization) at z >~ 6 • GRBs = biggest explosions in Universe, massive star explosions to z ~ 6 • MBH - Mbulge => all spheroids have BHs with fixed mass ratio. BH and Galaxy evolution are causally connected • Quasars ~ AGN on 1e7 smaller scales • double pulsars + Glob Cluster pulsars, gravity waves -- unprecedented labs for tests strong field GR • Extrasolar planets -- they are everywhere! • Proto-planetary disks: clear signatures of planet formation • Kuiper-belt objects -- what is Pluto? • Mapping Universe -- SDSS, FIRST, NVSS, COSMOS, UDF, …

7. Three year process run by ISAC • Experiment based: Quantified ‘experiments’ for future large area cm telescopes – not just radio astronomy reviews nor root N science • 50 chapters, 90 contributing authors, 25% theorists, but minority of multiwavelength observers

8. Key Science Projects: (i) Address key questions, (ii) Unique role of radio, or complementary but critical, (iii) Excites broad community Cosmic reionization and first light: IGM evolution through HI 21cm line + gas/dust/SF/AGN in first galaxies Dark energy and galaxy evolution: All sky HI (+ continuum) survey Origin and evolution of cosmic magnetism: all sky RM survey Strong field tests of GR using pulsars Cradle of Life: protoplanetary disks on (sub)AU scales + astrobiology + SETI

9. All require sensitivity: A/T >= 1e4 m^2/K • Most require frequencies >= 10 GHz • Many require > 1deg^2 FoV at 1.4 GHz • Some require > 1000 km baselines • Some require multibeaming • Downside -- still too broad to be practical for one facility

10. SKA path-finders (spurred, in part, by SKA science discussions) • HI 21cm survey instruments • ASKAP (Oz) -- $100M • MeerKAT (SA) -- $100M • PrepSKA (EU) -- $50M • Apertif (WSRT FPA) -- $10M • Reionization experiments • LOFAR -- $100M • MWA -- $10M • PAPER -- $2M

11. SKA phased approach • Phase I: SKA mid, 0.5 to 3 (or 10?) GHz, 10% collecting area, some long baselines, tile arrays + small dishes, large FoV • Phase II: Full SKA mid, plus full SKA low (70 -- 200MHz) • Phase III: up to 25GHz -- not specified as to how, or when, to get there (and why 25GHz vs. 45GHz?) Phase I Phase II

12. Optical/near-IR Telescope Science Priorities • Thirty meter telescope: Science themes, mostly spectra • Spectroscopic exploration of First Light and reionization -- Pop III stars and first galaxies • Exploration of galaxies and LSS in young Universe: spectroscopy of galaxy assembly • Investigation of massive black holes throughout cosmic time: coeval formation gal/BH • Exploration of planet formation processes and the characterization of extrasolar planets

13. Optical/near-IR Telescope Science Priorities • JWST: science themes, mostly near-IR imaging + spectra • First light and cosmic reionization • Assembly of galaxies and black holes • Birth of stars and proto-planetary systems: dusty disks in near-IR • Planets and the origins of life: imaging extrasolar giant planets + KPOs…

14. Optical/near-IR Telescope Science Priorities • LSST: Project based • Constraining dark energy and dark matter: very large volume survey • Taking an inventory of the solar system • Exploring the transient optical sky • Mapping the Milky Way

15. FIR Space Telescopes • Herschel: Science theme based • How galaxies formed and evolved in the early universe, and the nature of enormously powerful galactic energy sources. • The formation, evolution, and interrelationship of stars and the interstellar medium in the Milky Way and other galaxies. • Chemistry in our galaxy. • Molecular chemistry in the atmospheres of Mars and our solar system's comets and giant planets, and the nature of comet-like objects in the Kuiper belt beyond Neptune.

16. Xray Telescopes • Constellation X: Experiment based • Black Holes: Using black holes to test General Relativity (GR) and measuring black hole spin • Dark Energy: Improving the constraints on the key Dark Energy (DE) parameters by a factor of ten • Missing Baryons: Unambiguous detection of the hot phase of the Warm-Hot Intergalactic Medium (WHIM) at z>0 • Neutron Star Equation of State: Measuring the mass-radius relation of neutron stars to determine the Equation of State (EOS) of ultra-dense matter

17. Common ground and radio contributions Theme Telescopes Radio role

18. Other Radio Discussions • RMSPG: Haynes et al.Facility approach • Written as radio input to senior review • Excellent summary of existing facilities • Chicago I, II, III: NRAO/AUI/NAIC coordinated effort to consider scientific future of radio astronomy, in preparation for DS2010 • Engage broader community -- optical, theory, high energy (not connected to SKA) • No clear consensus on science, although some support for HI surveys • Working groups established: produce WP for DS2010 • SKA low (Beasley chair) • SKA mid (Lazio/Myers) -- RSST • SKA high -- no current WG?

19. AUI Futures of Radio Astronomy Committee: Chair D. McCray • Science theme approach: • Beyond standard model of physics and cosmology • Origin/evol galaxies • Origin/evol stars/planets/life • The high energy Universe • Fundamental and extreme physics • Current recommendations (likely to be much revised): • Maintain a balanced and vigorous program in RMS science and technology development • Develop, test, prototype and implement technologies leading to SKA-class facilities • Nurture partnerships leading to SKA-class facilities

20. McCray Summary at Jan08 AAS • Ensure proper operation of ALMA, EVLA, GBT: ease of use for non-experts, grants => leverage capital investment • Maintain technical development and educational aspects at (some) UROs. • Emphasize surveys -- FPAs, wide field imaging. • SKA -- stay the course of TDP, not ready for $100M investment. • No specific statement on VLBA or Arecibo.

21. Closing ruminations ALMA • Development plan ($10M/yr): science working groups and implementation opportunities provides natural forum for continued advancement of science case and instrument • Should NRAO secure access to supporting facilities (LMT, CCAT…)? EVLA: re-energize the community (and staff!), led by SAGE • Regenerate science case in modern context: phase I, II, III (?) • and/or DRSP for EVLA • EVLA science meeting(s) • Needed if want any chance of getting proper User support $$ • Might present path forward for DS2010

22. Closing ruminations VLBA: active staff participation in upgrade planning GBT: clear near-term priorities for instrument development SKA and DS2010 NRAO/AUI has conducted three major forums to determine the way forward for DS2010: Chicago meetings, AUI Futures Committee, Strategic planning retreats Thus far, no clear consensus has been reached in any forum.

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