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RAS E-ELT meeting 9th May 08 Fraser Clarke Towards EPICS; high contrast spectroscopy Fraser Clarke N Thatte, G Salter, M Tecza C Verinaud, M Kasper (EPICS co-PIs) R Gratton (EPICS science team)
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RAS E-ELT meeting 9th May 08 Fraser Clarke EPICS top level requirements EPICS is the proposed planet finding instrument for the E-ELT Two modes of operation –Imaging spectroscopy –Polarimetric imaging Top Level Requirements –600-1700nm (goal 350-2500nm) [600-900 for Polarimetry] –R>50 for discovery; R>>50 for characterisation [Spectroscopy] –Nyquist sampled imaging (2mas/pixel) –2” FoV (goal 4”) –Inner Working Angle < 30mas (goal 15mas) –Strehl at H~90% (I=9) [>50% at 600nm for Polarimetry] –Coronagraphic rejection better than 10 4 (tbc) –Polarimetric sensitivity 10 -5 Phase A study underway now. Due to be completed by Oct 2009.
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RAS E-ELT meeting 9th May 08 Fraser Clarke EPICS key science 1.Young self-luminous gas giants in star forming regions or young associations –Determine frequency and mass distribution of giant planets 2.Detection and characterisation of mature gas giants at orbital distances between ~5 and 15AU in the solar neighbourhood (15pc) 3.Imaging and characterisation of warm or young Jupiters previously found by R.V. or imaging searches with smaller telescopes –Understand giant planets’ atmospheric composition and structure 4.Detection and 1st order characterisation of warm Neptunes, massive rocky planets and super-Earths around very nearby stars (<10pc); with ultimate goal of detecting such planets located in the HZ (M-dwarfs and systems <4pc)
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RAS E-ELT meeting 9th May 08 Fraser Clarke EPICS consortium G Tinetti (UCL)
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RAS E-ELT meeting 9th May 08 Fraser Clarke Oxford involvement in EPICS Niranjan Thatte leads IFS workpackage –Oxford concentrates on Image Slicers –INAF/Padova (R Gratton) developing “BIGRE” lenslet approach Oxford deliverables; –IFS optical design analysis –Slicer prototype –SINFONI coronagraph (not funded in EPICS Phase A, but present in list of deliverables!) –Data reduction algorithms
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RAS E-ELT meeting 9th May 08 Fraser Clarke Speckles; limits on high contrast Light not put into diffraction limited core of PSF interferes coherently to produce speckles Some speckles, caused by imperfections in optical train, are long lasting (many minutes, or more), and cannot be integrated out –Super-speckles Super-speckles are diffraction limited, and look like real objects at a given wavelength => Major limit to contrast in current systems
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RAS E-ELT meeting 9th May 08 Fraser Clarke A third way… (wavelength) Speckles scale with wavelength ( /D), so they move out from central star as one goes to longer wavelengths Planets are at a fixed position on the sky which doesn’t change with wavelength Use wavelength scaling of Airy pattern and speckles to remove starlight and isolate planet’s signature. (Sparks & Ford 2002)
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RAS E-ELT meeting 9th May 08 Fraser Clarke Concept demonstrator AB Dor C as target 5 mag fainter companion 200 mas away VLT + SINFONI data DDT P76 (end of January 2006) 2 x 20 min on-source in two rotator settings First Airy Null at 60 mas in K band. Results published in; –Thatte et al 2007, MNRAS, 378, 1229 –Close et al 2007, ApJ, 665, 736
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RAS E-ELT meeting 9th May 08 Fraser Clarke Spectroscopy at the diffraction limit Input data cube (normalised)
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RAS E-ELT meeting 9th May 08 Fraser Clarke Spectroscopy at the diffraction limit Subtracted azimuthally averaged PSF Stepping through in wavelength from 1.45- 2.4um
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RAS E-ELT meeting 9th May 08 Fraser Clarke Super speckles in the raw data Subtract azimuthally averaged PSF Monochromatic image Super-speckles clearly visible
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RAS E-ELT meeting 9th May 08 Fraser Clarke Super speckles after processing Same wavelength slice after SD technique Speckles well removed
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RAS E-ELT meeting 9th May 08 Fraser Clarke 9 mag at 0.2” w/o coronagraph!! Thatte et al, 2007, MNRAS, 378, 1229
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RAS E-ELT meeting 9th May 08 Fraser Clarke Spectra of AB Dor C
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RAS E-ELT meeting 9th May 08 Fraser Clarke Spectral type of AB Dor C Close et al., 2007,ApJ, 665, 736
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RAS E-ELT meeting 9th May 08 Fraser Clarke Spectral type of AB Dor C Close et al., ApJL, submitted
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RAS E-ELT meeting 9th May 08 Fraser Clarke Steps towards EPICS Continuing to improve SD technique for EPICS data (Graeme Salter) Simulated data cube provided by C Verinaud for EPICS –1024x1024 with 444 wavelengths –Many speckles and “N” planets…
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RAS E-ELT meeting 9th May 08 Fraser Clarke Found 6 of 7 planets! SD technique found 6 of 7 planets in the datacube (Differential imaging only found 2) Particularly good further from star, where speckles move more. Tiger-stripe issue understood (fitting error), and should be fixed now
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RAS E-ELT meeting 9th May 08 Fraser Clarke Summary EPICS phase A study progressing, and due for submission to ESO by Oct 2009 Oxford leading IFS work package Many pronged approach to investigating high contrast capabilities of image slicers 1.Slicer bench test in the lab 2.SINFONI coronagraph test on sky 3.Optical design analysis 4.Development of new data reduction techniques
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RAS E-ELT meeting 9th May 08 Fraser Clarke Global plan - IFS optical design analysis Get complex amplitudes (post-coronagraph and exAO) from Christophe’s simulation Add IFS induced aberrations using optical design of IFS Try to quantify difference between IFS detected data cube and input data cube in terms of limiting contrast Input steps: static only, incl. AO + coronagraph, varying atmospheric turbulence IFS steps: Design only, manufacturing too.
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RAS E-ELT meeting 9th May 08 Fraser Clarke Progress - slicer prototype Price quote for slicer prototype 1 arm spectrograph optics available Need lab test up with phase screen, and simple coronagraph (or should we move our setup somewhere else) Procurement for detector and readout system launched.
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RAS E-ELT meeting 9th May 08 Fraser Clarke Progress - SINFONI coronagraph Proposal to ESO for instrument upgrade in preparation MPE would not like to be formally involved, but offers to help. Request for manpower funding to go in to STFC soon (already?) Hardware funding? (ESO)
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