MCAO A Pot Pourri: AO vs HST, the Gemini MCAO and AO for ELTs Francois Rigaut, Gemini GSMT SWG, IfA, 12/04/2002

December 4,2002GSMT SWG2 UH-88”, Courtesy W.Brandner, 0.65” seeing Filters: H K’ CO CO cont. 4’ IRS7 SgrA* >10 stars per arcsec 2 at K~18 Bow shock Very high extinction clouds 40” 5” >220 stars in 5”x5” IRS8 (bow shock)

December 4,2002GSMT SWG3 Arches Cluster 2.2 micron image. Young Star cluster in Galactic center region (10 Million years old) –Up-left: HST/NICMOS –Up-right: Gemini/Hokupa’a –Lower-right: Gemini/seeing 0.5”

December 4,2002GSMT SWG4 Gemini goes ~ 5-10x deeper Angular Resolution : –HST = 0.19” –Gemini = 0.13” Luminosity Function

December 4,2002GSMT SWG5 HST/NICMOS Gemini/Hokupa’a

December 4,2002GSMT SWG6

December 4,2002GSMT SWG8

December 4,2002GSMT SWG9 This figure shows a ten minute exposure of GG tau using this technique compared to the HST/NICMOS image from Silber et al. (2000). The Hokupa'a image comfirms the suspected gap in the disk that fell in the diffraction spikes of HST/NICMOS as well as revealing new structure in the disk. Guyon

December 4,2002GSMT SWG10 MPE Group: GC results

December 4,2002GSMT SWG11 NAOS results

December 4,2002GSMT SWG12 Classical AOMCAO No AO 165’’ MCAO Performance Summary Early NGS results, MK Profile 2 DMs / 5 NGS 320 stars / K band / 0.7’’ seeing 1 DM / 1 NGS Stars magnified for clarity

December 4,2002GSMT SWG13 Effectiveness of MCAO Numerical simulations: 5 Natural guide stars 5 Wavefront sensors 2 mirrors 8 turbulence layers MK turbulence profile Field of view ~ 1.2’ H band

December 4,2002GSMT SWG14 PSF Characteristics H Band [16,17,8] actuators Median seeing, CP 200 PDE/sub/ms for H.Order WFS Least square MCAO AO Distance off-axis [“] Strehl ratio FWHM [arcsec] Distance off-axis [“] 50% Enc.En.  [“] 0.1” Slit Coupling Distance off-axis [“] 0.7 mag IFU: > 1 mag 3x 10x Most of area is here !

December 4,2002GSMT SWG15 The Gemini MCAO in brief... Baseline system (17,19,12) actuators across beams, 3DMs, 5 WFS+LGS (125 PDE/subaperture/frame ~ 10W) Field average Strehl under median seeing conditions at zenith (no NGS noise) SS Band AO-only S Overall S *FWHM Limiting mag † J 41% 20%0.032’’ 26.3 H 60% 40%0.042’’ 25.0 K’ 75% 60%0.057’’ 24.9 *includes mostly low order aberrations from telescope and instrument, and AO calibration errors. † 5 sigma in 1 hour, extrapolated from the Hokupa’a results H band Sky Coverage : 15% (b=90 o ), 70% (b=30 o )

December 4,2002GSMT SWG16 MCAO, CAO, HST & NGST Sensitivities Limiting magnitudes, 5 , 3600sec, aperture = 2x2pixels Median seeing No AO MCAO HST NGST R~5 [magnitude (nJy)] 23.2 (370) 24.9 (76) 23.7 (230)28.0 (4.4)  m23.2 (370) 24.9 (76) 23.7 (230)28.0 (4.4) 24.8 (190) 26.3 (50) 26.0 (66)28.6 (6.0)  m24.8 (190) 26.3 (50) 26.0 (66)28.6 (6.0) R~10000 [magnitude (  Jy)] 20.4 (4.8) 20.3 (4.8) 17.2 (92)20.1 (6.1)  m20.4 (4.8) 20.3 (4.8) 17.2 (92)20.1 (6.1) 21.3 (4.7) 20.5 (9.7) 17.9 (107)20.5 (9.7)  m21.3 (4.7) 20.5 (9.7) 17.9 (107)20.5 (9.7) slit width (at K) 0.4” 0.066” 0.22” 0.066” Chun et al: confirmed spectroscopy 1 <  < 2.5  m will be detector limited  Nearly half (11/25) of the DRM’s can be started and explored by Gemini  The MCAO Science Case workshop

December 4,2002GSMT SWG17 Various AO modes and first order performance

December 4,2002GSMT SWG18 Relative Gain of groundbased 20m and 50m telescopes compared to NGST Groundbased advantage NGST advantage Imaging Velocities ~30km/s

December 4,2002GSMT SWG19 ELT-AO Fundamental Challenges Sky Coverage (independent of D) S.C.  0.1% (V), 2% (K), 20% (L-M) Solutions:  Laser Guide Stars  Multiple faint Natural GSs LGS Cone effect: S  exp[- (D/d 0 ) 5/3 ] S cone (1  m) = 0.5 (8-m), < 0.01 (50-m) Solution:  Multiple beacons 90 km Path diff. and “Missing” Data Open-loop measurements of off-axis LGS (large dynamic range, sensitivity loss) Solution:  Multi-Conjugate AO

December 4,2002GSMT SWG20 Scaling and Orders of magnitude versusD FoV  #DM  #act/DMD (1+a  ) #WFS/GS - -(1+b  ) #pix/s/WFSD Computing Pow.D 4 -6 (1+c  ) 2 100GF 30PF 800PF Laser power*-/D/D W 80W 160W 1: D=30 m, =1  m, FoV= 1’ 2: D=50 m, =0.5  m, FoV= 2’ 3: D=100 m, =0.5  m, FoV= 2’ >>> Fundamental limits: #DM (,  ), #GS > #DM <<< Fov = 2’, ~ 6 DM / FoV = 4’, 15 DMs ! (at ~ 1 micron) * no smart tricks

December 4,2002GSMT SWG21 Sample Numerical Results (CP Turbulence, 3 DM’s) Sample Numerical Results (CP Turbulence, 3 DM’s)

December 4,2002GSMT SWG22 Critical Technology to develop Deformable Mirrors : –Deformable secondaries (butable) –Dense / Compact DMs (d=1mm? 8’ waffers / 5mm Xinetics) High speed CCD arrays for WFS Fast computers/Alternative control schemes –“segmented pupil” –Layer oriented WFSs Lasers (short pulses) Cost: $50 to $100M. To be started ASAP. AO defines the ELT’s critical path !