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1 Key Types Introduction Michelson Summer School on High-Contrast Imaging Caltech, Pasadena 20-23 July 2004 Wesley A. Traub Harvard-Smithsonian Center.

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Presentation on theme: "1 Key Types Introduction Michelson Summer School on High-Contrast Imaging Caltech, Pasadena 20-23 July 2004 Wesley A. Traub Harvard-Smithsonian Center."— Presentation transcript:

1 1 Key Types Introduction Michelson Summer School on High-Contrast Imaging Caltech, Pasadena 20-23 July 2004 Wesley A. Traub Harvard-Smithsonian Center for Astrophysics

2 2 C, IWA, OWA types perturbations Reminders of main topics

3 3 C Ref: McCarthy & Zuckerman (2004); Macintosh et al (2003) 20 arcsec radius circle K~20 mag Bkgd objects 7 arcsec wand J~21 mag Bkgd object

4 4 Search space: best to date Airy Halo 1.Keck 2.IRCAL, Lick AO, K 3.Ks, AO, NACO, VLTI 4.WFPC2, HST, I 5.CFHT, AO, H 6.Keck NICMOS, 10sig 7.50% det, HST, H 8.XAO, 10m, R, 2007

5 5 Earth & Jupiter-Saturn, 100 stars Simulations by Bob Brown, STScI

6 6 Earth & Jupiter-Saturn Regions

7 7 Radial-velocity Stars

8 8 RV stars and brown dwarfs

9 9 1.8-m range

10 10 TPF-C Range

11 11 C, IWA, OWA Contrast C: Example: C = 10 -10 driven by Earth/Sun = 2x10 -10. Inner working angle IWA: Example: IWA = 3 /D driven by 1 AU/10pc = 0.100 arcsec. Outer working angle OWA: Example: OWA = 48 /D driven by N = 96 actuator DM.

12 12 Image-plane coronagraph simulation Ref.: Pascal Borde 2004 1st pupil 1st image with Airy rings mask, centered on star image 2nd pupil Lyot stop, blocks bright edges 2nd image, no star, bright planet

13 13 Wide-band (quadrant-phase) mask

14 14 Shaped-pupil mask Kasdin, Vanderbei, Littman, & Spergel, preprint, 2004 Pupil: Spergel-Kasdin prolate-spheroidal mask Image: dark areas < 10 -10 transmission Image: cut along the x-axis v u A(x, 0) = exp(-(  x/ ) 2 ) A(0, y) = periodic & messy x y

15 15 Discrete-mapped pupil (2): Densification Entrance pupil, sparsely filled FOV is small. Image with many aliases Densified pupil Clean image, narrow FOV

16 16 Continuous-mapped pupil Compact star image, easily blocked Input wavefront: uniform amplitude. Mirror 1 Mirror 2 Output wavefront: prolate-spheroidal amplitude. 100 dB = 10 -10 = 25 mag Output image: prolate spheroid

17 17 Nulling-shearing coronagraph

18 18 Phase ripple and speckles No DM: With DM: Phase ripples from primary mirror errors Polishing errors on primary Speckles generated by 3 sinusoidal components of the polishing errors Pupil plane Image plane

19 19 Phase + amplitude ripple and speckles h(u) =  n (a n +ia n ')cos(Knu) + (b n +ib n ')sin(Knu) = total ripples Describes all possible phase and amplitude ripples (= errors). DM can give I(  ) =  (0) +  n [(b n ’) 2 + (a n ’) 2 ]  (k  +Kn)  bigger speckles + [ 0 + 0 ]  (k  -Kn)]  smaller (zero) speckles


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