The color of trigger H4043, defined by the ratio of
total counts in Fregate band C (30-400 keV) to band A (7-40 keV)
vs. band B (7-80 keV) to band A, overlaid on a the color-color
plot of all localized bursts detected to date. Note the separation
of XRFs, XRRs, and GRBs.
The signal to noise in Fregate band C (30-400 keV)
of trigger H4043 in relation to the S/N of band C
of other localized HETE triggers. We find empirically that
most XRFs are faint and soft: the fact that localized bursts
require a minimum S/N in the 2-25 keV band means that the
band C S/N should be low. We find a cutoff in the band
C S/N of 6.5 delineates the XRF/non-XRF population with
high reliability.