[vsnet-grb 181497] GCN/IPN_RAW Timestamp-only Notices

[Bacodine]

TO:  All GCN Notice Customers
RE:  Resumption of the IPN_RAW notice type
DT:  01 Aug 2012
FR:  Kevin Hurley, Scott Barthelmy


INTRODUCTION:

Recently, discussions with several experimenters, whose instruments
collect very large amounts of daily data, have indicated that there is
a need for a rapid notification of the times of GRBs, so that a
relatively small amount of experiment data can be saved for later
analysis.  This has led to the development of a new subtype of the
IPN_RAW Notice type.  It will contain only the trigger times of GRBs
and candidate GRBs.  These times will be obtained automatically from
INTEGRAL SPI-ACS, Konus-Wind, and Suzaku WAM triggers.

The IPN_RAW Notice Type was initially introduced as a means to
circulate preliminary information on Interplanetary Network GRBs.
Currently, there are 3 types of notices based on IPN information:
IPN_RAW which contains a timestamp, an event duration, and an
Earth-crossing window; IPN_SEGMENT which contains the intersection
of an IPN annulus and a large errorbox location; and IPN_POSITION
which contains an error region ("box") formed from multiple annuli.
Because the information for an IPN_RAW had to be generated by hand
for each GRB, it proved to be too time-consuming to maintain, and
the last IPN_RAW notice was sent out in 2009.  We are announcing
a change to only the IPN_RAW notice type.  It is being split into two subtypes:
(a) the new timestamp-only subtype, and
(b) the original definition timestamp + event_duration + Earth-cross_window.
At this time, it is unclear if the latter form will ever be issued again,
but we are keeping the option open.


CONTRIBUTING IPN MISSIONS:

The new IPN_RAW Notices will contain only the trigger times of GRBs and
candidate GRBs.  These times will be obtained automatically from
INTEGRAL SPI-ACS, Konus-Wind, and Suzaku WAM triggers (others may be added
in the future).


TIME DELAYS:

The delay between the trigger time and the notice will be a function
of the downlink times of the various missions, but most delays
will not exceed one day, and should be considerably shorter in most cases.
Note that different instruments may trigger on different parts of a GRB,
so that in extreme cases, GRB emission may be occurring within
several hundred seconds of a trigger time.


OCCURRENCE RATES:

The IPN detects approximately 325 confirmed GRBs per year; about 200 of
them are INTEGRAL, Konus, and/or Suzaku triggers.  Of the 325, about 100
are not detected or are not localized by Swift or Fermi.  Of the 100,
most, but not all, are triggers; some are found in later analysis 
of untriggered data, and at the present time, we will not announce them
in the IPN_RAW Notices.

About 60 triggers/year are from unconfirmed GRBs; these are typically events
which are observed by a single IPN instrument, and they cannot be localized
by triangulation, although in some cases, very coarse localization information
can be obtained for them by other means.  IPN experiments also trigger
on particles and solar flares, and the automated procedure cannot distinguish
between various event types, although this can be done in later analysis.

About 100 IPN triggers/year are from GRBs which are detected and localized
by the Swift BAT and/or the Fermi GBM.  Usually, triangulation of these events
can refine the Fermi localization, but not the Swift ones.

To summarize, about one IPN_RAW Notice will be generated each day,
and multiple Notices can be generated for a given burst.


POSSIBLE USE CASE:

Since this type contains only the timestamp of a GRB/Transient/noise,
it is envisioned that this Notice type is suitable for those sites
that want to time-correlate any detections in their instruments
with those mission-instruments in the IPN network.  (This use-case is similar
to that of the sub-threshold notice types from Swift-BAT and INTEGRAL.)


LOCALIZATIONS CAN COME LATER:

Every IPN event is analyzed, and its origin (solar, confirmed cosmic,
unconfirmed cosmic, particle) and localization are determined if possible.
Since most IPN localizations are judged not to warrant rapid follow-up observations,
only about 20 per year are announced in GCN Circulars.  The data on all
IPN localizations, however, are public and are available at ssl.berkeley.edu/ipn3,
or by contacting khurley at ssl.berkeley.edu.


ACTION ITEM:

If, after reviewing the information above/below, you want to receive
these IPN_RAW, please send me a request to have them enabled.  You can do this
by forwarding this email (which has your important sitename identifier)
to scott at milkyway.gsfc.nasa.gov .
Or you can go to  http://gcn.gsfc.nasa.gov/gcn/config_builder.html
and select "#2 Modify an existing config".
Your current configuration is appended below.
(You can also take this opportunity to make other changes to your configuration.)


REMINDER OF RECENT ADDITIONS TO GCN:

In case you have missed them, here is a brief list of the most recent additions
to the GCN system.  You might consider signing up for these Notice types as well.
The full announcements/descriptions for each of these can be found at:  http://gcn.gsfc.nasa.gov/gcn/whats_new.html
SWIFT_BAT_SUB_SUB_THRESHOLD (May 2012) // Swift-BAT Triggers with very low significance; use for temporal coincidences
VOEvent Direct Server (Mar 2012)       // Added 3 VOEvent servers to allow for direct distribution of VOEvents
FERMI_LAT_MON/_TRANS (Aug 2011)        // Flare-ups from known sources monitored by Fermi-LAT & non-GRB transients
FERMI_LAT_GND (Aug 2011)               // Automated ground processing to get GRB positions
MOA  (Aug 2011)                        // Locations of up-coming gravitational lensing events
DOW_TOD  (Jun 2011)                    // Preprogrammed notices at specific days-of-week & time-of-day
FERMI_GBM FIN_POS  (Jun 2011)          // Human-in-the-loop ground-based analysis
MAXI_UNKNOWN/_KNOWN (Apr 2011)         // Unknown transients & Flare-ups from Known sources
INTEGRAL_WEAK  (Feb 2011)              // Subthreshold detections by INTEGRAL
SWIFT_BAT_MONITOR (Feb 2010)           // Flare-ups from known sources monitored by Swift-BAT


Sincerely,
Scott

Scott Barthelmy                      NASA-GSFC, Code 661, Greenbelt, MD   20771
PHONE:  301-286-3106                 (office)       CELL:   301-346-3733
EMAIL:  scott at lheamail.gsfc.nasa.gov
PAGER:  3013463733 at cingularme.com
WEB:    http://gcn.gsfc.nasa.gov/gcn


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DATES      25jun05   23oct07
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DIST_METHOD   EMAIL
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POC_NAME      Daisaku Nogami
POC_ADDRESS   vsnet-grb at ooruri.kusastro.kyoto-u.ac.jp
DAILY_REPORT_ENABLE   0
DAILY_REPORT_ADDRESS  vsnet-grb at ooruri.kusastro.kyoto-u.ac.jp
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