Science Team Management Claire Max Sept 14, 2006 NGAO Team Meeting

High-level goals of science team Define key science cases where NGAO will make large qualitative difference Perform trade studies for those parameters that most affect each specific science case Ditto for those parameters that most affect AO system design choices Develop and document the scientific and user requirements for the NGAO system, including science instruments –Science Requirements Document Iterate with system design team

One view: major iterations between science requirements and system design November 3, 2006 – First version of Science Requirements Document, based largely upon “point design” developed last spring March 7, 2007 – Second version, based on work of science team to refine requirements and understand capabilities of AO architectures July 9, 2007 – Third version January 9, 2008 – Fourth version (last one for System Design Phase)

The process for each science area, in brief Understand and document science requirements x and y, including how they interact with requirement z. –Iterate with performance budget for various AO architectures, to understand what is feasible both scientifically and technically. –Emphasize those science requirements that will yield the most science return (qualitatively new regimes, major new capabilities on key issues,...). –Emphasize those science requirements that will most stress the AO system design Develop and document observing scenarios. Understand and document requirements on science instruments. Develop prioritized instrument list. Iterate with instrument selection and error budgets. Deliver (next version of) Science Requirements Document.

Science areas in System Design Plan 2.1.1Solar System Companions and multiplicity of small solar system bodies Moons of the giant planets Shape and size of asteroids 2.1.2Galactic Science Galactic Center proper motions: astrometry Galactic Center radial velocities: integral field spectroscopy Galactic Center: nature of Sag A*

Science areas, continued 2.1.2Galactic Science, continued Low-mass companions: planets and binary brown dwarfs Debris disks, protostellar envelopes, outflows: Contrast Debris disks, protostellar envelopes, outflows: Polarimetry

Science areas, continued 2.1.3Extragalactic Science Resolved stellar populations High redshift galaxies Nearby galaxies and AGNs Gravitational lensing

Science areas chosen for first few months Topics we thought would be the most stressing for AO system design, or most informative for choice of system architecture Relate to key error budgets for the AO system Galactic Center –Proper motions  astrometry error budget Debris disks and binary brown dwarfs –Contrast error budget Photometry of crowded fields, resolved stellar pop’s –Photometry error budget in the confusion limit High-redshift galaxies –IFU spectroscopy  encircled energy error budget –(Maybe) Recovering stellar populations for galaxy sub-components  photometric accuracy for faint, isolated, slightly extended objects

General comments We will need to engage astronomers who are actively working in each of these fields. The figure of merit from the “science” point of view isn’t an error budget. Figure of merit needs to be scientific. Notional examples on the next slide. Once we’ve developed figures of merit that make sense, we will ask how they affect “science requirements” for NGAO system

Examples of possible figures of merit (please come up with better ones!) Galactic Center proper motions –How accurately do we need to determine stellar orbits, for purposes of –measuring GR effects? –determining origin of the young stars? –detecting new kinematic subsystems? –What astrometric accuracy is needed for each? Debris disks and binary brown dwarfs –What contrast ratios are needed in order to –Constrain theories of disk formation –Detect and characterize planet-induced gaps in disks –Constrain formation scenarios for brown dwarf binaries –Measure masses of brown dwarfs

Figure of merit examples, continued Photometry of crowded fields –What Strehl, over what field of view, is needed to extract unambiguous stellar populations for –Globular clusters? Local Group galaxies? More distant galaxies (and how distant)? –How do we define “unambiguous” for this science? How good is “good enough? High-redshift galaxies –Surveys: Sky coverage fraction, observing efficiency, and throughput –Spectroscopy: What is optimum IFU slitlet size and hence enclosed energy diameter for measuring redshift of galaxies in various redshift ranges? How well do we need to measure redshift? –Imaging and photometry: What photometric accuracy is needed in order to extract “unambiguous” stellar populations from bulge, disk components separately? How do we define “unambiguous” for this science? How good is “good enough”?

How to proceed? Today –Discuss each of the first series of science cases –Come up with preliminary “figures of scientific merit” –Discuss the AO design issues most affecting the science case –Lay out “next steps” Next few months (leading up to Nov 3rd delivery of Science Requirements Document) –Convene in small, focused groups within each topic –Decide what simulations will be needed, which are in hand already –Address the first iteration of science requirements with AO system design