Handling of magnitude systems
The handling of magnitude systems was a bit confuse in version 2.0. We now use (for versions >=2.2) a more comprehensive scheme.
fitmodel.card, each magnitude system is identified by a key referencing a description file in the data directory. For instance,
As for previous versions, the key has to be mentionned in the light curves, along with the instrument name and the pass band. For instance,
The description file contains the path to a calibrated spectrum of a reference star ( in ergs/s/cm2/A), and a list of magnitudes for this star for various instruments and pass-bands. For instance,
# 2009 release of CALSPEC @SPECTRUM MagSys/bd_17d4708_stisnic_002.ascii # Magnitudes in the Landolt system : Landolt & Uomoto (2007) STANDARD U 9.724 STANDARD B 9.907 STANDARD V 9.464 STANDARD R 9.166 STANDARD I 8.846 # Magnitudes in the Megacam local natural system : Regnault et al (2009), Table 7 MEGACAM u 9.7688 # annexe papier calib08 MEGACAM g 9.6906 MEGACAM r 9.2183 MEGACAM i 8.9142 MEGACAM z 8.7736
The labels for instruments has to be the same as in the fitmodel.card file:
The pass bands have to match those in the instrument filter wheel file.
... @FILTERS FilterWheel ...
U U_bessel sux-shifted.dat B B_bessel sb-shifted.dat V V_bessel sv-shifted.dat R R_bessel sr-shifted.dat I I_bessel si-shifted.dat
The only exception is the AB magnitude system which directly implemented in the C++ code.