This parameter pulls double duty, used to enter the radiation
temperature in units of 10K in the case of a blackbody or
bremsstrahlung input model. It also is used to input
the power-law index (in energy),
, in the case of a power-law model. Note
that
is defined as in
so generally
will be less than zero (this is the opposite of the convention
used by xspec). XSTAR always works with
specific luminosity
in units erg s
erg
,
and never uses
or
, for example.