SPITZER PHOTOMETRY OF THE TRANSITING EXOPLANETS CoRoT-1 AND CoRoT-2
25th CoRoT Scientific Council : 24-25 sept 2007 - M.O. - L.J. Evaluation of exo N1 data M.Ollivier -...
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Transcript of 25th CoRoT Scientific Council : 24-25 sept 2007 - M.O. - L.J. Evaluation of exo N1 data M.Ollivier -...
25th CoRoT Scientific Council : 24-25 sept 2007 - M.O. - L.J.
Evaluation of exo N1 data
M.Ollivier - L Jorda
25th CoRoT Scientific Council : 24-25 sept 2007 - M.O. - L.J.
Goal of the evaluation
• Check if N1 data are compliant with N1 specifications
• Global noise not larger than 1.5 times the photon noise for a K0 star of mag 14 (photon noise = 700 ppm over 512 seconds, 250 ppm over 1hour)
25th CoRoT Scientific Council : 24-25 sept 2007 - M.O. - L.J.
Conclusion of first evaluation (june 2007)
• White photometry– Pb with outliers (SAA)– Pb with hot pixels, particularly when present in a
background window – When outliers are flagged and kept away, specification is
reached whatever the magnitude is
• Colored photometry– Drift (red : positive slope, green and blue : negative
slope)– As a consequence, specification in term of stability is not
reached (even if OK fter slope correction).
Conclusion : not far from N1 requirements
25th CoRoT Scientific Council : 24-25 sept 2007 - M.O. - L.J.
What has changed in the pipeline ?
• Optimisation of parameters for cosmics detection
• Flag of the SAA input / output (not implemented in tested data)
• How to correct hot pixels (cf. VL and MA presentations)
25th CoRoT Scientific Council : 24-25 sept 2007 - M.O. - L.J.
Method
• Starting from N1 data (LRc01 in this case, IR01 in previous evaluation)
• Use of unflagged data only• 512 second sampling• Removal of low frequencies (substraction of a fit
over 16 samples)• Removal of outliers (only unflagged points)• Evaluation of mean and variance of residuals
25th CoRoT Scientific Council : 24-25 sept 2007 - M.O. - L.J.
White photometry1 hour White photometry
0
0,5
1
1,5
2
2,5
3
3,5
4
11,8 12 12,2 12,4 12,6 12,8 13 13,2 13,4 13,6
Magnitude
S/N (photon noise unit)
25th CoRoT Scientific Council : 24-25 sept 2007 - M.O. - L.J.
White photometry (2)
• Very few outliers that have not been detected and flagged
• The hot pixels are very present and really need to be treated.
25th CoRoT Scientific Council : 24-25 sept 2007 - M.O. - L.J.
Colored photometry• Real pb of color correction in quite all LRc01 LCs.
25th CoRoT Scientific Council : 24-25 sept 2007 - M.O. - L.J.
Colored photometry (2)Colored photometry
0
2
4
6
8
10
12
11,8 12 12,2 12,4 12,6 12,8 13 13,2 13,4 13,6
Magnitude
S/N (photo noise unit)
25th CoRoT Scientific Council : 24-25 sept 2007 - M.O. - L.J.
Colored photometry (3)
• Intra color correction not optimized
• Pb of drift not corrected
• S/N requirement not compliant with the specification
Colored photometry processing must be improved (by the project or by users ?)
25th CoRoT Scientific Council : 24-25 sept 2007 - M.O. - L.J.
Conclusions
• White photometry is OK (from S/N requirement point of view)
• A processing for of hot pixels should be implemented
• Colored photometry is still not at the required level.
25th CoRoT Scientific Council : 24-25 sept 2007 - M.O. - L.J.
“nice” LCs
25th CoRoT Scientific Council : 24-25 sept 2007 - M.O. - L.J.
“nice” LCs