GCN Circular 2421

HETE Prompt GRB Light Curves and Color-Color Diagrams

The HETE team has implemented software which will automatically post to 
the HETE web site (http://space.mit.edu/HETE/Bursts) lightcurves from 
localized GRBs within minutes of the reception of the full burst data 
set.  The lightcurves are in ASCII format and include time since trigger 
(seconds), and Fregate band A, B, and C counts/second, where band A is
7-40 keV, band B is 7-80 keV, band C is 30-400 keV, and the bin size is 
160ms.  The lightcurves will typically cover a five-minute time period 
starting roughly two minutes before the burst trigger time, and so will 
include ample data for fitting the background.

A sample of such a lightcurve file can be found at

  http://space.mit.edu/HETE/Bursts/GRB030723/GCN_LCs-H2777.dat

The burst web page will also include a color-color diagram calculated 
from the counts fluence in Fregate bands A, B, and C.  This color-color 
diagram, which plots the ratio of band B to band A counts fluence vs. 
the ratio of band C to band A counts fluence, is useful in distinguishing
XRFs from classical GRBs, and X-ray rich GRBs form a bridge between the 
two distributions:  for an example, see

  http://space.mit.edu/HETE/Bursts/GRB030723

Further improvements in the prompt data to the web page are being 
implemented and will be announced soon.