1. 1 Leonardo Pinheiro da Silva Corot-Brazil Workshop – October 31, 2004 Corot Instrument Characterization based on in-flight collected data Leonardo Pinheiro da Silva Corot-Brazil Workshop October 31, 2004

2. 2 Leonardo Pinheiro da Silva Corot-Brazil Workshop – October 31, 2004 Introduction Some instrument components are susceptible to physical phenomena leading to undesired effects on the scientific data some might be corrected through modeling, with basis on correlated collected data (e.g. HK data) others are expected to be negligible, given the defined specifications for the photometric signal

3. 3 Leonardo Pinheiro da Silva Corot-Brazil Workshop – October 31, 2004 Objectives Though the analysis and characterization of some critical aspects we intend to: validate the theoretical models to be used on ground- based corrections evaluate the respective modeling parameters verify the hypothesis enabling some of the noise sources to be neglected

4. 4 Leonardo Pinheiro da Silva Corot-Brazil Workshop – October 31, 2004 instrument optics CCD detectors readout electronics Some Aspects of Interest - PSF (Temp. of the Lenses) - Bias Level (Temp. of Analogic Comp.) - Electronics’ Gain (Aging) - Spontaneous Generation of e - (CCD Temp.) - Pixel Response Non-Uniformity (+Attitude Jitter) - p + Impacts (Geo. Position, Effective Shielding)... digital processing

5. 5 Leonardo Pinheiro da Silva Corot-Brazil Workshop – October 31, 2004 Reduction of in-flight calibration data to provide: Dark Fields Bright pixels map Dark current law as f(T) Flat Fields Black pixels map Local PRNU statistics I. CCDs: Classic Characterization

6. 6 Leonardo Pinheiro da Silva Corot-Brazil Workshop – October 31, 2004 CCDs are susceptible to radiation which depends: on the satellite position in orbit on the effective shielding Effect on the photometry will depend on: the energy of incoming impacts (generated e - ) the impacted area of the CCD (disturbed pixels) Specific tools to characterize: incoming impacts as a function of satellite coordinates impact effects on the CCD (energy and scale statistics) CCDs: p + Flux at the Focal Plane

7. 7 Leonardo Pinheiro da Silva Corot-Brazil Workshop – October 31, 2004 (…) Set of images + satellite orbit data => p + flux (lat, lon) [p + /cm 2 /s] CCDs: p + Flux at the Focal Plane (lat,lon)

8. 8 Leonardo Pinheiro da Silva Corot-Brazil Workshop – October 31, 2004 II. Optics: Spread Function Collected star light is spread over a region of the detector’s surface distribution profile depends on stellar magnitude and type, position in the field of view, lenses’ temperature,.. Knowledge about the spread function is useful in jitter corrections and star coordinates evaluation Specific tools to estimate: high-resolution (sub-pixel) spread functions, given a set of images and corresponding satellite attitude data

9. 9 Leonardo Pinheiro da Silva Corot-Brazil Workshop – October 31, 2004 Spread Function: Sampled Data acquired data projected image spline interpolation

10. 10 Leonardo Pinheiro da Silva Corot-Brazil Workshop – October 31, 2004 Spread Function: Data Acquisition (m=6; T=6000K)restituted image ? attitude jitter spatial sampling

11. 11 Leonardo Pinheiro da Silva Corot-Brazil Workshop – October 31, 2004 Spread Function: Restitution typical sample projected image restituted image

12. 12 Leonardo Pinheiro da Silva Corot-Brazil Workshop – October 31, 2004 III. Readout Electronics Signal conditioning is done between the CCD outputs and A/D conversion Signal is amplified, an offset is imposed Components are sensitive to thermal fluctuations and aging Specific tools to characterize the behavior of: the offset level the electronic gain the readout noise

13. 13 Leonardo Pinheiro da Silva Corot-Brazil Workshop – October 31, 2004 Astero 1L Exo 1L Exo 2L Astero 2L Correlation to T probes, thermal sensitivity, temporal evolution, spectra,.. Example: Electronic Bias

14. 14 Leonardo Pinheiro da Silva Corot-Brazil Workshop – October 31, 2004 Conclusion Data processing algorithms have been developed with basis on available in-flight data and calibration requirements The set of algorithms has been integrated in a mock-up and will soon be migrated to an operational structure Further work is to be done on other instrument aspects which might also be interesting to characterize...