Shapelet Space STEP
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Shapelet Space Shapelet Space STEP STEP F. William High F. William High , , Research Assistant Research Assistant Caltech Caltech Tuesday, July 26, 2005 Tuesday, July 26, 2005
description
Shapelet Space STEP. F. William High , Research Assistant Caltech Tuesday, July 26, 2005. Overview. Set σ γ / n 1/2 ~ 0.1% n g ~ 100/arcmin 2 σ γ ~ 0.3 n im = 50 or 100 Various θ px HDF Galaxies (mostly) Raytraced PSFs FOV 200”x200” SNAP 160”x160” ACS. T exp 1 ks SNAP wide - PowerPoint PPT Presentation
Transcript of Shapelet Space STEP
Shapelet Space Shapelet Space STEPSTEPF. William HighF. William High,,Research AssistantResearch AssistantCaltechCaltech
Tuesday, July 26, 2005Tuesday, July 26, 2005
7/26/20057/26/2005 Shapelet Space STEPShapelet Space STEP F. William High, CaltechF. William High, Caltech
OverviewOverview
Set Set σσγγ//nn1/21/2 ~ 0.1% ~ 0.1% nngg ~ 100/arcmin ~ 100/arcmin22
σσγγ ~ 0.3 ~ 0.3 nnimim = 50 or 100 = 50 or 100
Various Various θθpxpx
HDF Galaxies (mostly)HDF Galaxies (mostly) Raytraced PSFsRaytraced PSFs FOVFOV
200”x200” SNAP200”x200” SNAP 160”x160” ACS160”x160” ACS
HDFHDF
Raytraced Raytraced PSFsPSFs
Measure Measure ShapeletsShapelets
Change Change orientation, orientation, size, flux, size, flux, ShapeletsShapelets
ShearShear PSF PSF convolveconvolve
TTexpexp
1 ks SNAP wide1 ks SNAP wide 2 ks ACS WFPC22 ks ACS WFPC2
Uniform across “chip”:Uniform across “chip”: DepthDepth NoiseNoise Input shearInput shear PSFPSF
7/26/20057/26/2005 Shapelet Space STEPShapelet Space STEP F. William High, CaltechF. William High, Caltech
The StarsThe Stars
Label: Label: psf*psf*
PSFPSF SourceSource
A, BA, B SNAP SNAP BaselineBaseline
Steve Kent’s Steve Kent’s `raytrace` `raytrace` softwaresoftware
CC 1.4 meter 1.4 meter “SNAP”“SNAP”
Also Also `raytrace``raytrace`
D-LD-L ACSACS TinyTimTinyTim
Our PSFs account for:Our PSFs account for:
• Diffraction, including strutsDiffraction, including struts
• Charge diffusionCharge diffusion One globular cluster per psf*One globular cluster per psf*
Convolve in Shapelet spaceConvolve in Shapelet space
7/26/20057/26/2005 Shapelet Space STEPShapelet Space STEP F. William High, CaltechF. William High, Caltech
The GalaxiesThe Galaxies
Label: Label: psf*psf*
PSFPSF θθpxpx Object Object TypeType
AA SNAP SNAP BaselineBaseline
0.05”0.05” ShapeletShapelet
BB 0.10”0.10”
CC 1.4 meter 1.4 meter “SNAP”“SNAP”
0.040.04
DD ACSACS 0.04”0.04”
EE 0.10”0.10”
FF 0.04”0.04” ExponentialExponential
GG 0.10”0.10”
H-LH-L 0.04”0.04” ShapeletShapelet
Lo
garith
mic
Lo
garith
mic
grayscale
grayscale
Shear to 4Shear to 4thth order order in Shapelet spacein Shapelet space
7/26/20057/26/2005 Shapelet Space STEPShapelet Space STEP F. William High, CaltechF. William High, Caltech
The NoiseThe Noise
Shot noiseShot noise: readout, zodiacal (but : readout, zodiacal (but background subtracted)background subtracted) Exposure timeExposure time ttexpexp = ~1 ks SNAP, ~2 ks ACS = ~1 ks SNAP, ~2 ks ACS
Larger Larger θθpxpx @ fixed t @ fixed texpexp ↔ larger noise ↔ larger noise &&
signal-to-noisesignal-to-noise
Perfect Perfect Charge Transfer EfficiencyCharge Transfer Efficiency UncorrelatedUncorrelated: pre-: pre-drizzledrizzle
7/26/20057/26/2005 Shapelet Space STEPShapelet Space STEP F. William High, CaltechF. William High, Caltech
The ResultThe Result
7/26/20057/26/2005 Shapelet Space STEPShapelet Space STEP F. William High, CaltechF. William High, Caltech
ConclusionConclusion
962 images, 7-11 arcmin962 images, 7-11 arcmin22, 40 Gb total, 40 Gb total ftp://ftp://www.astro.caltech.edu/pub/fwh/SpaceSTEPwww.astro.caltech.edu/pub/fwh/SpaceSTEP//
100+ parallel processors @ NERSC/LBL100+ parallel processors @ NERSC/LBL Email Will (Email Will ([email protected]@astro.caltech.edu) and ) and
Richard (Richard ([email protected]@astro.caltech.edu) with ) with questionsquestions
Deadline: mid-SeptemberDeadline: mid-September
