relative fluxes

[Miguel Cerviño]

> Does this only arise on the theory side?  The justification would be  
> stronger for a general solution if there were also empirical use  
> cases.

:), It also could be stronger if we are looking for interoperability  
in the analysis of data in the VO:
If you look to transform observed data (fluxes) in physcal properties  
(luminosities, ages etc)
you need theoretical models....


>
>> If you work with color (also theoretical) you need the offset (zero  
>> point) and the scalling factor (solar masses)
>
> How should this be expressed?  For example:  units = 1.33 Msun +  
> 0.43 ?

Not exactly: the 1.33 Msun multiplies the value in the table first and  
0.43 is added after the multiplication operation... (it like the  
translation from Celsius degrees to Farent. that I think has appeared  
some time ago here...)
Any case, I think that a filter zero point is relevant "per se" not  
only for theory, but for the description of filter system itself...

Since it is impossible to put all the astronomical community in common  
accord about units, maybe a parser can perform the operation (and in  
this case the final user can misunderstood what "units" means). May be  
use
the "scale" in the way Sebastian suggest and to add an "offset" field  
if needed is the more clear way...

cheers

	m


-------------------------------------------------------------
"Nunca se debe intentar contentar a
quienes nunca se van a dar por contentos"

                        Javier Marias

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