Compare performance of GSP-Phot to Andy's SICK code when fitting only BP/RP.
Investigate fitting BP/RP alone, RVS alone, and BP/RP+RVS simultaneously with Andy's SICK code.
Is this a route to beat APSIS?
Where can BP/RP help to estimate abundances from RVS?
Where can RVS help to improve on BP/RP?
This project employs synthetic MARCS spectra.
GSP-Phot vs. SICK
GSP-Phot and SICK overall agree very nicely. No algorithm clearly outperforms the other.
logg: GSP-Phot is slightly better than SICK. SICK may suffer from some convergence problems (red dots below dwarfs).
[Fe/H]: SICK is slightly better than GSP-Phot. GSP-Phot appears to systematically underestimate [Fe/H] by ~1dex for some stars. These problematic stars are fainter than G~15, i.e., SICK estimates [Fe/H] more robustly at lower S/N than GSP-Phot.
2000 synthetic MARCS spectra in Gaia BP/RP.
Mostly Main-Sequence dwarfs but also some giants.
Teff from 4000K to 8000K.
Test spectra created by GOG. (Not by our own forward models!)
Examples of posterior samples
Posterior distributions mostly well behaved for BP/RP, i.e., fast convergence, unimodal.
Even in simple case the posteriors cannot be well approximated by a Gaussian.
Rare examples with multimodal posterior.
Results for fitting BP/RP alone
Compare initial guesses of GSP-Phot and SICK. (Possibly SVM fails for noisy data, which may explain why SICK estimates [Fe/H] better at faint magnitudes.)
SICK: BP/RP alone vs. RVS alone
SICK: Fitting BP/RP and RVS simultaneously
tests/astropars/challenge3.txt · Last modified: 2014/10/31 13:55 by randrae