TABLE OF CONTENTS:
The GCN system has been modified to incorporate the distribution
of locations of GRBs detected by the INTEGRAL spacecraft;
both the localizations by ISGRI and the unlocalized detections
by the SPI Anti-Coincidence Shield (ACS).
About 1 times a month, there will be a GRB in the FOV
of the ISGRI instrument that is bright enough to be localized.
The telemetry from INTEGRAL is transmitted to the ground continuously.
On the ground, automated processing looks for "bursts" in the data stream
and calculates images. If a peak is found in an image
(with a high enough significance),
then that position is transmitted to the GCN system and then on to those
sites that have requested that type of Notice (and if the burst detection
meets the site's other filtering criteria).
Like all the other sources of GRB locations within the GCN system,
users can elect to receive (or not) these INTEGRAL Notices.
The GCN/INTEGRAL (Wakeup, Refined, Offline, Weak) Notices are archived within the GCN website
in the Table of INTEGRAL GRBs.
Notice Types, Content, and Purpose
There are 6 GCN/INTEGRAL Notice types. They are:
1) POINTDIR packets contain the RA,Dec look-direction of the s/c
after the next slew. The date and time of that upcoming slew
are also given. This serves as a heads-up to those sites
who want to track the INTEGRAL FOV to minimize the delay
until their first observation.
2) SPIACS packets notifies that SPI Anti-Coincidence Shield has detected a burst.
The date, time, and intensity are given. There can be no position information
from this type of burst detection. The SPIACS notices are archived at SPI-ACS Triggers, Lightcurves.
3) WAKEUP packets contain an RA,Dec location for the burst.
They are issued only once per burst, but may not be present for all bursts.
This type of Notice comes first in the sequence of Notices on the burst.
Since it is based on the least amount of data in the processing,
it has the lowest significant in the localization and lowest confidence
in the burst-vs-nonburst identification. (The threshold is 8 sigma.)
These WAKEUP Notices come from automated pipeline ground processing.
4) REFINED packets are issued only if there is more data
with an increased significance that improves the detection and localization
of the burst. There can be 0 to N of these Notces for each burst.
These REFINED Notices come from automated pipeline ground processing.
5) OFFLINE packets are generated manually by ground personnel.
Typically, only one Notice will be issued for each burst,
but the possibility for more than one is allowed for exceptional cases.
The OFFLINE Notice represents the final confirmation (or rejection)
of a GRB and contains the most accurate GRB properties distributed by IBAS.
The typical time delay for these Notices is 1 to a few hours.
6) WEAK packets are subthreshold event triggers (ie sigma is in the range 6.5 to 8.)).
This is below the normal threshold level for the ALERTs, REFINEDs, and OFFLINE.
These may or may not be followed by ALERTs, REFINEDs, and OFFLINE;
it depends on the later portions of the lightcurve.
Many (fraction is TBD) of these WEAKs are false positives.
This notice type is intended for automated/robotic telescopes
that do not incur human reasources to follow-up these low-probability triggers.
The automated ground-based analysis of the INTEGRAL telemetry
will generate GRB notifications and positions in real time.
In addition, human-involved analyses of the data may result
in a revised position within a few hours after the burst.
The timescales and localization precisions at the various Notice types are as follows:
Subtype Time since burst Loc precision Comments ======= ================ ============= ======== WEAK ~?min <4' Low-significance events WAKEUP ~1min <4' First Notice with a position REFINED 1-2min <4' Uses more data (if a long burst) OFFLINE 1-3 hr <4' Human-involved post-processing SPI_ACS ~1min n/a Timestamp only; no position information
The sequence of activities for a typical burst follows:
1) The ISGRI instrument detects a rate increase (a "trigger").
2) The data is transmitted to the ground and processed at the ISDC.
This trigger detection is within ~1 min of the actual onset of the burst.
3) A "wakeup" message is generated by the IBAS automated processing s/w (few sec).
It is forwarded to the GCN computer, where it is received, reformated,
and distributed to those sites wishing that Notice type.
The INTEGRAL-to-GCN-to-World PROCEDURE:
Like the other missions that contribute GRB positions, GCN receives those
positions messages from the respective mission operations teams, reformats
them into the standard GCN formats, and distributes them to the sites
using the usual distribution methods and filtering. INTEGRAL is no different.
Samples of the E-mail, Pager, Short-form Pager, & Subject-only
distribution methods of the five GCN/INTEGRAL Notice types are included below.
The format is very similar to the other spacecraft-instrument sources of GRB locations.
The socket packet contents and format are similar to the other mission-specific packet types
and are described in detail in the socket packet definition document.
This document also has explanations of the various fields in the packet (their content, values, and
implications for use), and those same fields are manifested in the various email and pager formats.
The POINTDIR Notice is type=51;
the SPIACS Notice is type=52;
the WAKEUP Notice is type=53;
the REFINED Notice is type=54;
the OFFLINE Notice is type=55; and
the WEAK Notice is type=56.
Sites can elect to receive each of the 6 INTEGRAL Notice types on a Notice by Notice basis.
There is a separate dis/enable bit for each type.
See filtering to see which filter functions are applicable.
This filtering applies to all the existing distribution methods/media.
The uncertainty in the location will depend on (a) the burst intensity,
(b) its position relative to ISGRI's FOV, and
(c) the relative locations and intensities of other sources in the FOV.
The typical error for the WAKEUP Notice is ultimately 6-8 arcmin (diameter),
and ~6 arcmin (diameter) for the REFINED and OFFLINE Notices.
The WEAK Notices will have a ~8 arcmin (diameter) error circle.
The systematic uncertainty depends on the satellite attitude knowledge
and varies from 0 arcmin to ? deg (diameter) in the worst situations.
The errors quoted in the Position Notices includes only the statistical contribution.
To allow sites to "practice" on INTEGRAL Notices, there are INTEGRAL Test Notices.
There is a flag (in the socket pkts) which indicates if the current packet
is a "real" Notice or a Test Notice. Each of the 6 types uses this 'test' flag bit.
Sites can elect to receive these INTEGRAL Test Notices. There is only
one controlling parameter in the "sites.cfg" file for each site.
This controls all 6 "test" versions of the 6 INTEGRAL Notices. If this flag is on
then the site will receive 'test' version of each of the 6 basic types.
Currently, these 'test' Notices come from the INTEGRAL operations center, and are issued every 6 hours.
(If there is a desire from the user community, GCN will implement its own version
of Test Notices for INTEGRAL (much like the Test Notices for the BATSE and HETE missions).)
The INTEGRAL spacecraft pointing direction (ie FOV) is always known via the POINTDIR Notices.
It is therfore possible to minimize the slewing time of a ground-based telescope
by having it looking at the RA,Dec listed in the POINTDIR Notices.
Further, the telescope can continuously tile the FOV in a "patrol" mode
all night long thereby obtaining images just prior to the burst.
This is most suitable for automated systems.
Sites are encouraged to acknowledge INTEGRAL and GCN in their publications
based on follow-up observations using these GCN/INTEGRAL locations.
For further information on this, please contact
Scott Barthelmy (for GCN issues),
or see the
INTEGRAL (IBAS at ISDC), and
INTEGRAL (IBAS at Milano), Then click "IBAS Alerts Page Updated in REAL TIME!" to get the Alerts Tables, and
INTEGRAL (ISDC) web page,
INTEGRAL (ESA) web page,
and
these GCN web pages, and
GCN/INTEGRAL GRB table.
Examples of the 6 Notice types of the e-mail formats are shown below.
The "/////" divider bars are NOT part of the messages.
Do not take the actual values shown in these examples as real GRBs.
While based on trial & real data from the mission,
they have been adjusted to provide a broader representation
of the various combinations of fields and value ranges.
For those sites/people that use demons and/or incoming e-mail filters,
the "Subject" lines for the all notice types are fixed,
and the strings are:
for the 4 burst-position-based Notices (Weak, Wakeup, Refined, & Offline):
GCN/INTEGRAL_POSITION
for the Pointing_Direction Notice:
GCN/INTEGRAL_POINTING_DIR
for the SPI ACS burst timestamp Notice:
GCN/INTEGRAL_SPIACS_TRIGGER
/////////////////////////Wakeup e-mail format///////////////////////////////
TITLE: GCN/INTEGRAL NOTICE
NOTICE_DATE: Thu 27 Feb 03 08:43:48 UT
NOTICE_TYPE: INTEGRAL Wakeup
TRIGGER_NUM: 214, Sub_Num: 0
GRB_RA: 74.3243d {+04h 57m 18s} (J2000),
74.3711d {+04h 57m 29s} (current),
73.5841d {+04h 54m 20s} (1950)
GRB_DEC: +20.4849d {+20d 29' 05"} (J2000),
+20.4896d {+20d 29' 23"} (current),
+20.4079d {+20d 24' 28"} (1950)
GRB_ERROR: 5.00 [arcmin, radius, statistical only]
GRB_INTEN: 15.82 [sigma]
GRB_TIME: 31336.25 SOD {08:42:16.25} UT
GRB_DATE: 12697 TJD; 58 DOY; 03/02/27
SC_RA: 82.22 [deg] (J2000)
SC_DEC: 15.98 [deg] (J2000)
SUN_POSTN: 339.98d {+22h 39m 55s} -8.44d {-08d 26' 31"}
SUN_DIST: 97.03 [deg]
MOON_POSTN: 296.68d {+19h 46m 42s} -25.14d {-25d 08' 36"}
MOON_DIST: 140.88 [deg]
GAL_COORDS: 180.87,-13.81 [deg] galactic lon,lat of the burst
ECL_COORDS: 75.33, -2.16 [deg] ecliptic lon,lat of the burst
COMMENTS: INTEGRAL GRB Coordinates.
/////////////////////////Refined e-mail format//////////////////////////////
TITLE: GCN/INTEGRAL NOTICE
NOTICE_DATE: Thu 27 Feb 03 08:43:59 UT
NOTICE_TYPE: INTEGRAL Refined
TRIGGER_NUM: 214, Sub_Num: 1
GRB_RA: 74.3243d {+04h 57m 18s} (J2000),
74.3711d {+04h 57m 29s} (current),
73.5841d {+04h 54m 20s} (1950)
GRB_DEC: +20.4849d {+20d 29' 05"} (J2000),
+20.4896d {+20d 29' 23"} (current),
+20.4079d {+20d 24' 28"} (1950)
GRB_ERROR: 5.00 [arcmin, radius, statistical only]
GRB_INTEN: 15.82 [sigma]
GRB_TIME: 31336.25 SOD {08:42:16.25} UT
GRB_DATE: 12697 TJD; 58 DOY; 03/02/27
SC_RA: 82.22 [deg] (J2000)
SC_DEC: 15.98 [deg] (J2000)
SUN_POSTN: 339.98d {+22h 39m 55s} -8.44d {-08d 26' 31"}
SUN_DIST: 97.03 [deg]
MOON_POSTN: 296.68d {+19h 46m 42s} -25.14d {-25d 08' 36"}
MOON_DIST: 140.88 [deg]
GAL_COORDS: 180.87,-13.81 [deg] galactic lon,lat of the burst
ECL_COORDS: 75.33, -2.16 [deg] ecliptic lon,lat of the burst
COMMENTS: INTEGRAL GRB Coordinates.
/////////////////////////Offline e-mail format//////////////////////////////
TITLE: GCN/INTEGRAL NOTICE
NOTICE_DATE: Thu 27 Feb 03 09:29:48 UT
NOTICE_TYPE: INTEGRAL Offline
TRIGGER_NUM: 214, Sub_Num: 2
GRB_RA: 74.3243d {+04h 57m 18s} (J2000),
74.3711d {+04h 57m 29s} (current),
73.5841d {+04h 54m 20s} (1950)
GRB_DEC: +20.4849d {+20d 29' 05"} (J2000),
+20.4896d {+20d 29' 23"} (current),
+20.4079d {+20d 24' 28"} (1950)
GRB_ERROR: 5.00 [arcmin, radius, statistical only]
GRB_INTEN: 15.82 [sigma]
GRB_TIME: 31336.25 SOD {08:42:16.25} UT
GRB_DATE: 12697 TJD; 58 DOY; 03/02/27
SC_RA: 82.22 [deg] (J2000)
SC_DEC: 15.98 [deg] (J2000)
SUN_POSTN: 339.98d {+22h 39m 55s} -8.44d {-08d 26' 31"}
SUN_DIST: 97.03 [deg]
MOON_POSTN: 296.68d {+19h 46m 42s} -25.14d {-25d 08' 36"}
MOON_DIST: 140.88 [deg]
GAL_COORDS: 180.87,-13.81 [deg] galactic lon,lat of the burst
ECL_COORDS: 75.33, -2.16 [deg] ecliptic lon,lat of the burst
COMMENTS: INTEGRAL GRB Coordinates.
/////////////////////////Point_Dir e-mail format////////////////////////////
TITLE: GCN/INTEGRAL NOTICE
NOTICE_DATE: Sun 02 Mar 03 01:08:36 UT
NOTICE_TYPE: INTEGRAL Pointing Direction
NEXT_POINT_RA: 264.6968d {+17h 38m 47s} (J2000)
NEXT_POINT_DEC: -31.6639d {-31d 39' 49"} (J2000)
SLEW_TIME: 74518.00 SOD {20:41:58.00} UT
SLEW_DATE: 12699 TJD; 60 DOY; 03/03/01
SUN_POSTN: 342.33d {+22h 49m 19s} -7.50d {-07d 29' 49"}
SUN_DIST: 75.52 [deg]
MOON_POSTN: 330.31d {+22h 01m 14s} -17.42d {-17d 25' 08"}
MOON_DIST: 60.45 [deg]
GAL_COORDS: 356.90, -0.19 [deg] galactic lon,lat of the pointing direction
ECL_COORDS: 265.44, -8.31 [deg] ecliptic lon,lat of the pointing direction
COMMENTS: INTEGRAL Slew Notice.
/////////////////////////SPIACS e-mail format///////////////////////////////
TITLE: GCN/INTEGRAL NOTICE
NOTICE_DATE: Sat 31 Aug 02 21:08:02 UT
NOTICE_TYPE: INTEGRAL SPI ACS Trigger
GRB_INTEN: 1134 [sigma]
GRB_TIME: 43403.68 SOD {12:03:23.68} UT
GRB_DATE: 12417 TJD; 143 DOY; 02/05/23
COMMENTS: INTEGRAL GRB SPI_ACS Trigger.
////////////////////////////////////////////////////////////////////////////
/////////////////////////Weak e-mail format///////////////////////////////
TITLE: GCN/INTEGRAL NOTICE
NOTICE_DATE: Thu 27 Feb 03 08:43:38 UT
NOTICE_TYPE: INTEGRAL Weak
TRIGGER_NUM: 214, Sub_Num: 0
GRB_RA: 74.3245d {+04h 57m 18s} (J2000),
74.3713d {+04h 57m 29s} (current),
73.5843d {+04h 54m 20s} (1950)
GRB_DEC: +20.4848d {+20d 29' 05"} (J2000),
+20.4895d {+20d 29' 23"} (current),
+20.4078d {+20d 24' 28"} (1950)
GRB_ERROR: 5.00 [arcmin, radius, statistical only]
GRB_INTEN: 6.82 [sigma]
GRB_TIME: 31326.25 SOD {08:42:06.25} UT
GRB_DATE: 12697 TJD; 58 DOY; 03/02/27
SC_RA: 82.22 [deg] (J2000)
SC_DEC: 15.98 [deg] (J2000)
SUN_POSTN: 339.98d {+22h 39m 55s} -8.44d {-08d 26' 31"}
SUN_DIST: 97.03 [deg]
MOON_POSTN: 296.68d {+19h 46m 42s} -25.14d {-25d 08' 36"}
MOON_DIST: 140.88 [deg]
GAL_COORDS: 180.87,-13.81 [deg] galactic lon,lat of the burst
ECL_COORDS: 75.33, -2.16 [deg] ecliptic lon,lat of the burst
COMMENTS: INTEGRAL GRB Coordinates.
Examples of the 6 types of the (regular) pager formats are shown below. There are no "Subject" lines for these e-mails sent to the pager companies because the Subject line would use up valuable character counts from the maximum displayable for the body of the message.
/////////////////////////Wakeup Pager format////////////////////////////////// GCN/INTEGRAL GRB Wakeup RA=186.698d DEC=-62.789d TIME: 12:38:52.33 UT I=12.74 sigma /////////////////////////Refined Pager format///////////////////////////////// GCN/INTEGRAL GRB Refined RA=186.798d DEC=-62.879d TIME: 12:38:52.33 UT I=13.33 sigma /////////////////////////Offline Pager format///////////////////////////////// GCN/INTEGRAL GRB Offline RA=186.789d DEC=-62.883d TIME: 12:38:52.33 UT I=13.14 sigma /////////////////////////Point_Dir Pager format/////////////////////////////// GCN/INTEGRAL PointDir NEXT_RA=234.190d DEC=-45.340d SLEW_DATE_TIME: 03/03/02 16:31:46.00 UT /////////////////////////SPIACS Pager format////////////////////////////////// GCN/INTEGRAL GRB SPI_ACS Trigger TIME: 12:03:23.68 UT I=11.34 sigma /////////////////////////Weak Pager format////////////////////////////////// GCN/INTEGRAL GRB Weak RA=186.698d DEC=-62.897d TIME: 12:38:40.15 UT I=6.14 sigma //////////////////////////////////////////////////////////////////////////////
Examples of the 6 types of the short-form pager format are shown below. There are no "Subject" lines for these e-mails sent to the pager companies, because the Subject-line would use up valuable character counts from the maximum displayable for the body of the message. And it was the very limited display character count of some companies that motivated the short-form pager method in the first place.
/////////////////////////Weak Short-Pager format//////////////////////////// INTEGRAL Weak RA=0.536 DEC=+2.045d /////////////////////////Wakeup Short-Pager format//////////////////////////// INTEGRAL Wakeup RA=0.563 DEC=+2.054d /////////////////////////Refined Short-Pager format/////////////////////////// INTEGRAL Refined RA=0.573 DEC=+2.044d /////////////////////////Offline Short-Pager format/////////////////////////// INTEGRAL Offline RA=0.463 DEC=+2.044d /////////////////////////Point_Dir Short-Pager format///////////////////////// INTEGRAL Pointing Dir RA=-0.671 DEC=-0.292d /////////////////////////SPIACS Short-Pager format//////////////////////////// INTEGRAL SPI_ACS Trigger T=12:03:23.68 Inten=11.34 //////////////////////////////////////////////////////////////////////////////
There are two variations of the Subject-only format: decimal degrees and RA=hh:mm:ss Dec=DDdMMmSSs format. The two variations are shown below:
/////////////////////////Weak Subject-only format//////////////////////////// Subject: INTEGRAL Weak RA=186.689 DEC=-62.798d //////////////////////// Subject: INTEGRAL Weak RA=+12:26:73 DEC=-62:46:61 E=4.0arcmin T=12:38:40.33 I=6.14 /////////////////////////Wakeup Subject-only format//////////////////////////// Subject: INTEGRAL Wakeup RA=186.698 DEC=-62.789d //////////////////////// Subject: INTEGRAL Wakeup RA=+12:26:37 DEC=-62:46:16 E=4.2arcmin T=12:38:52.33 I=12.74 /////////////////////////Refined Subject-only format/////////////////////////// Subject: INTEGRAL Refined RA=186.698 DEC=-62.789d //////////////////////// Subject: INTEGRAL Refined RA=+12:26:37 DEC=-62:46:16 E=4.2arcmin T=12:38:52.33 I=12.74 /////////////////////////Offline Subject-only format/////////////////////////// Subject: INTEGRAL Offline RA=186.698 DEC=-62.789d //////////////////////// Subject: INTEGRAL Offline RA=+12:26:37 DEC=-62:46:16 E=4.2arcmin T=12:38:52.33 I=12.74 /////////////////////////Point_Dir Subject-only format///////////////////////// Subject: INTEGRAL PointDir RA=86.998 DEC=-33.149d //////////////////////// Subject: INTEGRAL PointDir RA=+04:26:37 DEC=-33:46:16 /////////////////////////SPIACS Subject-only format//////////////////////////// Subject: INTEGRAL SPI_ACS Time=12:38:52.33 Inten=12.74 //////////////////////// Subject: INTEGRAL SPI_ACS T=12:38:52.33 I=12.74 ///////////////////////////////////////////////////////////////////////////////
Here is an example of the INTEGRAL Test Notice (e_mail format).
//////////////////////////////////////////////////////////////////////////////
TITLE: GCN/INTEGRAL NOTICE
NOTICE_DATE: Wed 04 Sep 02 19:08:09 UT
NOTICE_TYPE: TEST INTEGRAL Offline
TRIGGER_NUM: 234, Sub_Num: 0
GRB_RA: 1.2037d {+00h 04m 49s} (J2000),
1.2343d {+00h 04m 56s} (current),
0.5630d {+00h 02m 15s} (1950)
GRB_DEC: +2.3323d {+02d 19' 56"} (J2000),
+2.3456d {+02d 20' 44"} (current),
+2.0539d {+02d 03' 14"} (1950)
GRB_ERROR: 1.02 [arcmin, radius, statistical only]
GRB_INTEN: 11.34 [sigma]
GRB_TIME: 43403.68 SOD {12:03:23.68} UT
GRB_DATE: 12417 TJD; 143 DOY; 02/05/23
SC_RA: 1.46 [deg] (J2000)
SC_DEC: 2.48 [deg] (J2000)
SUN_POSTN: 60.11d {+04h 00m 27s} +20.60d {+20d 35' 60"}
SUN_DIST: 60.14 [deg]
MOON_POSTN: 201.73d {+13h 26m 56s} -4.51d {-04d 30' 47"}
MOON_DIST: 159.43 [deg]
GAL_COORDS: 100.23,-58.47 [deg] galactic lon,lat of the burst
ECL_COORDS: 2.03, 1.66 [deg] ecliptic lon,lat of the burst
COMMENTS: INTEGRAL GRB TEST Coordinates.
//////////////////////////////////////////////////////////////////////////////