TO:  All GCN Notice recipients
RE:  A New INTEGRAL Notice type is available
DT:  24 Feb 2011


INTRODUCTION:

The GCN system has been modified to incorporate the distribution
of the INTEGRAL_WEAK position notices.

The INTEGRAL IBAS Team (Sandro Mereghetti et al) have added
a new message type ("Weak") (S.Mereghetti, Circ 11766)
to their existing list of "Wakeup", "Update" and "Offline" position
messages (and "PointDir" & "SPIACS").  This new notice type lowers
the trigger threshold from the normal 8.0 sigma value to 6.5 sigma.
(The original 3 position notice types still maintain their 8.0 sigma
threshold.)

CONFIDENCE LEVEL:
Since the threshold has been turned down, the likelihood of each trigger
being due to a real GRB (or other astrophysical transient) is low
(actual value is TBD).  Most of the triggers will be due to noise
fluctuations.  As such these WEAK Notices are most suited
for robotic telescopes that do not incur any/much human-related effort   
to make the observations.

LOCATION ERROR:
The position uncertainty is less than 4 arcmin (radius).

SEQUENCE OF NOTICES:
These Weak notices may occur (a) before the start of the usual
sequence of Wakeup, Update and Offline; or (b) stand-alone,   
ie not followed by one ore more of the others.  It all depends
on the time evolution of the signal in the IBIS detector. 

DISTRIBUTION and FORMAT:
This INTEGRAL_WEAK notice type (like the 5 original INTEGRAL types)
is available in all the GCN distribution methods and formats
(socket-based and e-mail-based).  The format for the "WEAK" notices
is exacly the same as the "Wakeup/Update/Offline" types
(both socket-packet & the various email formats; both regular
and VOEvent XML formats).

MORE INFORMATION:
Can be found at:  http://gcn.gsfc.nasa.gov/gcn/integral.html
And the socket packets contents/format can be found at:
http://gcn.gsfc.nasa.gov/gcn/sock_pkt_def_doc.html   
under Type=56.
Also:  http://www.isdc.unige.ch/integral/science/grb#IBAS

ACTION ITEM:
If you want to receive these INTEGRAL_WEAK position notices,
please send me a request to have them enabled.  You can do this
by forwarding this email to scott@milkyway.gsfc.nasa.gov .
Or use the web page:  http://gcn.gsfc.nasa.gov/gcn/config_builder.html
and select #2 (and type in your sitename).
(You can also take this opportunity to make other changes to your
configuration.)
Your current configuration is listed below.


Sincerely,
Scott

Scott Barthelmy                      NASA-GSFC, Code 661, Greenbelt, MD   20771
PHONE:  301-286-3106                 (office)       CELL:   301-346-3733
FAX:    301-286-1684                 (1st choice,  -1682 2nd choice)
EMAIL:  scott@lheamail.gsfc.nasa.gov
PAGER:  3013463733@cingularme.com
WEB:    http://gcn.gsfc.nasa.gov/gcn