TABLE OF CONTENTS:
1. Introduction and Background:
The GCN system distributes location information derived from the Interplanetary Network (IPN) @ UC Berkeley and the IPN @ GSFC. There are 3 variations of this IPN-based set of Notices. These IPN Notices are different than the regular GCN Notice (which contain burst information from a single instrument detection) in that these IPN Notices combine burst information 1, 2, 3 or more spacecraft.
The IPN is a system of spacecraft that use gamma-ray arrival time information at multiple spacecraft to triangulate the direction of a GRB. The mission-instruments that currently (as of Aug 2008) constribute to the IPN are: Mars_Odyssey-HEND, Mars_Odyssey-GRS, RHESSI, KONUS-Wind, Swift-BAT, MESSENGER-GRNS, Suzaku-WAM, INTEGRAL-SPIACS, SuperAGILE, AGILE-GRID, AGILE-MCAL, Fermi-GBM, and Fermi-LAT. Kevin Hurley (UCB), khurley@sunspot.ssl.berkeley.edu is the PI for the IPN.
2. The IPN Notice Types:
There are three variations of GCN/IPN information:
(1) IPN_POS,
(2) IPN_SEGMENT, and
(3) IPN_RAW.
These types along with their inputs and outputs are summarized in Table 1.
2.1) The IPN_POS type is the result of a 3 (or more) spacecraft IPN timing
triangulation solution. These are burst positions with small error boxes
(as opposed to the annulii, segments, or timestamps described below).
(On rare occaisions there will be two error boxes in the IPN_Position Notice
instead of the usual single error box.)
Here is the announcement for this new Notice type.
See the list of archived Position Notices.
2.2) The IPN_SEGMENT type combines the intersection of a 2-spacecraft-IPN annulus and an error circle from spacecraft-instrument that produces a large error circle. Combining the annulus plus an error circle yields a segment section along the annulus.
In the past (1995-2001), this large error circle instrument was BATSE. Coming soon (late 2008),
this IPN_SEGMENT type will resume by using Fermi-GBM as the large error-circle instrument.
The annulii segments are long (2-10 deg) and narrow (2-30 arcmin).
See the list of archived annulus Segment Notices.
2.3) The IPN_RAW type comes in two sub-types:
(a) a timestamp-only from a countrate increase detection by a single spacecraft, and
(b) an IPN annulus derived when two spacecraft detect the same burst.
The annuli are narrow (2-30 arcmin) and have a radius of 0-90 deg on the sky.
Here is the announcement for this new Notice type.
See the list of archived Raw Notices.
TYPE | NUM S/C | CONTRIBUTION CONTENT | OUTPUT CONTENT |
---|---|---|---|
IPN_POS | 3,4,5... | A Rate Increase Timestamp from each s/c | Error box |
IPN_SEGMENT | 2 | A Full Annulus and an Error Circle | Annulus segment |
IPN_RAW(1) | 1 | A single Rate Increase Timestamp | Timestamp |
IPN_RAW(2) | 2 | A Rate Increase Timestamp from each s/c | Full annulus |
3. The "IPN" Notice Sequence of Activities:
The following 3 sections descript the sequence of activities, data contributors, and the processing involved to produce the respective Notice types.
3.1) For IPN_POS:
a) The GCN system also runs "auto_near" (now defuuct) and "auto_konus" programs.
These two programs automatically receive daily transfers of data from the two spacecraft,
process them looking for GRBs, and when GRBs are found,
the extracted lightcurves (with timing information) are sent to K.Hurley's deamon at UCB.
b) A daemon on the UCB machine monitors for incoming NEAR and KONUS light curves,
and when it detects one it looks to see if the appropriate section
of the Ulysses data has been received from JPL/DSN.
If that portion of the data has not arrived,
it continues to periodically check until it does arrive.
c) Depending on the relative timing of the GRB and the data dumps through the DSN,
the wait can be 1-25 hours (more on the weekends).
d) When the Ulysses data has been transferred from JPL,
it is searched for a matching GRB and when a significant enough match is found,
IPN annuli are calculated and the resulting position(s) is sent back to GCN for distribution.
3.2) For IPN_SEGMENT:
The IPN_SEG Notices use the data from two different spacecraft.
The exact sequence of steps is:
In the CGRO-BATSE era:
a) When the GCN program detects a burst in the BATSE telemetry stream,
it produces a BATSE light curve in the 20-100 keV energy band
using the 1-sec sampled DISCLA data,
and sends that light curve to a machine at UCB. (T+5 min)
b) A daemon on the UCB machine monitors for incoming BATSE light curves,
and when it detects one it looks to see if the appropriate section
of the Ulysses data has been received from JPL/DSN.
If that portion of the data has not arrived,
it continues to periodically check until it does arrive.
c) Depending on the relative timing of the GRB and the data dumps through the DSN,
the wait can be 1-25 hours (more on the weekends).
d) When the Ulysses data has been transferred from JPL,
it is searched for a matching GRB and when a significant enough match is found,
an IPN annulus is calculated and sent back to GSFC.
e) This annulus is combined with the latest/best
BATSE-Original/-Final/-MAXBC/-LOCBURST/-AD error circle that is available
and a notice is composed and sent
to all GCN sites (this is the human-in-the-loop part).
The GCN system captures and automatically transfers to Kevin Hurley (UC Berkeley)
the BATSE light curve for a GRB. This gets the appropriate data to UCB a couple days
before the Huntsville BATSE team could do so, thus eliminating a couple days
from the total time delay. The range of time delays (T_burst to Notice_time)
is on average 24 to 48 hours (with the shortest being 11 hours to date).
The GCN system also processes the telemetry downloads from the Wind-KONUS and NEAR-XGRS instruments,
finds & extracts the GRBs in those data, and sends the lightcurves to the IPN deamon at UCB.
And from then on the sequence of processing events is the same, and the distribution
of the various IPN Notices types is the same. The time delays for these Notices
are comparable to the BATSE-Ulysses-based Notices, because the TM download latencies
of Wind and NEAR are comparable to Ulysses (CGRO-BATSE is the only real-time system, currently).
In the Fermi-GBM era:
It is the same as above except that the BATSE lightcurve is replaced with the GBM lightcurve, and
the BATSE error circle is replaced with the GBM error circle, and
Ulysses is replaced by a combination of non-earth-orbit spacecraft.
3.3) For IPN_RAW:
a) Any of the ~8 mission-instruments that contribute to the IPN systen (as of Aug 08)
search their respective data sets looking for countrate increases.
Some missions use human-search techniques and others use automated searches.
b) If the increase is determined to be due to a burst (as determined by humans in the loop
using the lightcurve shape and spectral information), then a message is sent to GCN
giving the date and time of the burst.
c) A daemon on the GCN imports this message, converts it to the standard GCN format,
and distributes it to those sites that have this IPN_RAW type enabled.
IPN_POS:
These can be used like any of the other (small) error box/circle position notices by follow-up instruments with small (10-20 arcmin) FOV.
IPN_SEG:
These can be use by either (a) instruments with large FOVs (1-10 deg), or
(b) by small FOV instruments that are willing to tile the annulus segment.
IPN_RAW:
Since this type contains only the timestamp of a GRB (and sometimes an annulus
on the sky), 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 might include not only
wide-angle optical cameras, but also neutrino, gravitational radiation,
and TeV detectors; although, of course, anybody is free to receive this Notice type.)
Not all timestamp notices will be followed up with localization information;
please contact Kevin Hurley and/or Valentin Pal'shin (khurley AT ssl.berkeley.edu,
val AT mail.ioffe.ru) if you need further information on an event.
For IPN_POS Notices, the error boxes will be in the several arcmin and above range. For about 55% of the Notices there will be only a single error box, but because 3 spacecraft yield only 2 unique annuli and these 2 annuli cross in 2 locations, there can be 2 error boxes reports (~25% of the cases). A 4th spacecraft or other directional information from some spacecraft (e.g. imaging from SAX-WFC or north/south ecliptic hemispheres from Wind-KONUS, etc).
For IPN_SEG Notice type, the annulii segments are long (2-10 deg) and narrow (2-30 arcmin) yielding an error box area of 4 sq.arcmin to 5 sq.deg.
For IPN_RAW Notice type, the annulii are narrow (2-30 arcmin) and have a radiius of 0-90 degrees.
TYPE | SHAPE | SIZE |
---|---|---|
IPN_POS | Box | X by Y arcmin |
IPN_SEGMENT | Annulus segment | 2-30 arcmin wide by 2-10 deg long |
IPN_RAW(1) | Full annulus | 2-30 arcmin wide, 0-90 deg radius |
IPN_RAW(2) | - | - |
6. Distribution Methods & Filter Functions:
Unlike all the other GCN notice types, the IPN_SEG Notices are currently only available via the full-format e-mail distribution method. The data set is not compatible with the Pager (long and short forms), or the Internet socket methods. See Table 3 for a breakdown of what Notice IPN Types are available via which distribution methods.
METHOD | POS | SEG | RAW |
---|---|---|---|
Socket | YES | NO | YES |
YES | YES | YES | |
Pager | YES | NO | YES |
SPager | YES | NO | YES |
Subject | YES | NO | YES |
Subject hh:mm | YES | NO | YES |
Sites can elect to receive each of the 3 IPN Notice types on a Type-by-Type basis.
There is a separate dis/enable bit for each type.
Filtering method "Visible" and "Night" do not apply the IPN_RAW and IPN_SEGMENT types.
However, Timedelay and ErrorBox_size filters do apply to all 3 types.
For all 3 types, the format of the full-format e-mail form (appended below) is very similar to the other sources in the GCN. It is based on a "TOKEN: value" scheme to allow for both the easy reading by humans and the easy parsing by computer daemons.
The packing format and content of the socket packet method is also very similar to that used in the othe socket packets. Those GCN sites using the Internet socket method should refer to the socket definition document to get the details (packet types 31, 32, and 39).
8.1) IPN_POS
Both variations of this Notice type are shown in Section 10.1
The single-box form is like the other notice type with the exception
that it has the RA,Dec locations fo the four corners of the box specified.
The two-box form has the center and 4 corners of the second box also given.
8.2) IPN_SEG
After the twenty or so lines of the "TOKEN: value's", a set of RA,Dec,Distance values sampled along the center-line of the annulus segment are listed. These RA,Dec values span the plus/minus 3-sigma confidence limits along the arc based on the uncertainty (statistical plus systematic) of the mission-instrument that provided the error circle. (In the past this was the BATSE-Original/-Final/MAXBC/-LOCBURST/-AD locations; and now it will be the Fermi-GBM error circles.) The distance value is the angular distance between the error-circle location and the sampled position along the arc. [Note: Earlier forms (pre 12Dec97) of these IPN_SEGMENT Notices did not have the distance column and only had the "Most Probably" location identified.]
The packing format and content of the socket packet method is also very similar to that used in the Original packets (type=1). Those GCN sites using the Internet socket method should refer to the socket definition document to get the details (this is packet_type=32).
8.3) IPN_RAW
Both variations of the Notice type are shown in Section 10.3 (the Timestamp-only and the Annulus).
For more information, please contact:
Scott Barthelmy (NASA-GSFC) (301-286-3106)
scott@lheamail.gsfc.nasa.gov
for GCN matters, and
Kevin Hurley (UCB)
khurley@sunspot.ssl.berkeley.edu
or
Valentin Pal'shin (Ioffe Physico-Technical Institute)
val@mail.ioffe.ru
for IPN related issues.
Here are two examples of the full e-mail distribution method. The first is an example of a 1-box Notice. In addition to the usual first few ilnes which are common to all GCN Notices, ther eis the RA,Dec for the center of the error box, then the RA,Dec of the 4 corners of the error box, the radius of the circle which circumscibes the diamond-shapped box, the area of the box in square arcminutes, the peak flux, fluence, and duration of the burst (if known; in first example they are not known; they are in the second example), and then the usual locations/distances of the Sun amd Moon, plus some comments.
The second example is that of a 2-box Notice. All the fields for the 1-box Notice are present, plus there is an additional RA,Dec for the center of the second box and the RA,Dec's for its 4 corners. The time interval for the PEAK_FLUX measurement may or may not be present from Notice to Notice.
===================== A Single Box Notice Example ============================= TITLE: GCN/IPN POSITION NOTICE NOTICE_DATE: Sun 03 Sep 00 18:59:47 UT NOTICE_TYPE: IPN Single Box IPN_NUMBER: 190 GRB_DATE: 11776 TJD; 233 DOY; 00/08/20 GRB_TIME: 31024.00 SOD {08:37:04.00} UT GRB_IPN_RA: 120.1544d {+08h 00m 37s} (J2000), 120.1616d {+08h 00m 39s} (current), 119.5881d {+07h 58m 21s} (1950) GRB_IPN_DEC: -17.1604d {-17d 09' 36"} (J2000), -17.1622d {-17d 09' 43"} (current), -17.0217d {-17d 01' 17"} (1950) GRB_ERROR1_RA1: 120.0077d {+08h 00m 02s} (J2000) GRB_ERROR1_DEC1: -17.2444d {-17d 14' 39"} (J2000) GRB_ERROR1_RA2: 120.5493d {+08h 02m 12s} (J2000) GRB_ERROR1_DEC2: -16.7594d {-16d 45' 33"} (J2000) GRB_ERROR1_RA3: 119.7892d {+07h 59m 09s} (J2000) GRB_ERROR1_DEC3: -17.5441d {-17d 32' 38"} (J2000) GRB_ERROR1_RA4: 120.3031d {+08h 01m 13s} (J2000) GRB_ERROR1_DEC4: -17.0753d {-17d 04' 30"} (J2000) GRB_ERROR: 21.28 [arcmin radius, 3 sigma] GRB_BOX_AREA: 196 [sq.arcmin] GRB_PEAK_FLUX: unknown [erg/cm2/sec] GRB_FLUENCE: unknown [erg/cm2] GRB_DURATION: unknown [sec] SUN_POSTN: 149.82d {+09h 59m 17s} +12.30d {+12d 17' 42"} SUN_DIST: 41.55 [deg] MOON_POSTN: 27.27d {+01h 49m 05s} +5.65d {+05d 39' 10"} MOON_DIST: 94.42 [deg] COMMENTS: IPN triangulation localization. COMMENTS: This is a preliminary, 3 sigma error box. COMMENTS: GCN message is being issued. ===================== A Double Box Notice Example ============================= TITLE: GCN/IPN POSITION NOTICE NOTICE_DATE: Sun 03 Sep 00 18:59:02 UT NOTICE_TYPE: IPN Double Box IPN_NUMBER: 187 GRB_DATE: 11776 TJD; 233 DOY; 00/08/20 GRB_TIME: 31024.00 SOD {08:37:04.00} UT GRB_IPN_RA: 120.1544d {+08h 00m 37s} (J2000), 120.1616d {+08h 00m 39s} (current), 119.5881d {+07h 58m 21s} (1950) GRB_IPN_DEC: -17.1604d {-17d 09' 36"} (J2000), -17.1622d {-17d 09' 43"} (current), -17.0217d {-17d 01' 17"} (1950) GRB_ERROR1_RA1: 120.0077d {+08h 00m 02s} (J2000) GRB_ERROR1_DEC1: -17.2444d {-17d 14' 39"} (J2000) GRB_ERROR1_RA2: 120.5493d {+08h 02m 12s} (J2000) GRB_ERROR1_DEC2: -16.7594d {-16d 45' 33"} (J2000) GRB_ERROR1_RA3: 119.7892d {+07h 59m 09s} (J2000) GRB_ERROR1_DEC3: -17.5441d {-17d 32' 38"} (J2000) GRB_ERROR1_RA4: 120.3031d {+08h 01m 13s} (J2000) GRB_ERROR1_DEC4: -17.0753d {-17d 04' 30"} (J2000) GRB_IPN2_RA: 134.3352d {+08h 57m 20s} (J2000) GRB_IPN2_DEC: -8.8200d {-08d 49' 11"} (J2000) GRB_ERROR2_RA1: 134.4769d {+08h 57m 54s} (J2000) GRB_ERROR2_DEC1: -8.7360d {-08d 44' 09"} (J2000) GRB_ERROR2_RA2: 133.7972d {+08h 55m 11s} (J2000) GRB_ERROR2_DEC2: -8.9647d {-08d 57' 52"} (J2000) GRB_ERROR2_RA3: 134.8437d {+08h 59m 22s} (J2000) GRB_ERROR2_DEC3: -8.6931d {-08d 41' 34"} (J2000) GRB_ERROR2_RA4: 134.1915d {+08h 56m 46s} (J2000) GRB_ERROR2_DEC4: -8.9054d {-08d 54' 18"} (J2000) GRB_ERROR: 21.28 [arcmin radius, 3 sigma] GRB_BOX_AREA: 196 [sq.arcmin] GRB_PEAK_FLUX: 2.7e-06 [erg/cm2/sec] in a 0.50 sec interval GRB_FLUENCE: 3.9e-05 [erg/cm2] GRB_DURATION: 39.0 [sec] SUN_POSTN: 149.82d {+09h 59m 17s} +12.30d {+12d 17' 42"} SUN_DIST: 41.55 [deg] MOON_POSTN: 27.27d {+01h 49m 05s} +5.65d {+05d 39' 10"} MOON_DIST: 94.42 [deg] COMMENTS: IPN triangulation localization. COMMENTS: This is a preliminary, 3 sigma error box. COMMENTS: GCN message is being issued.
This shows the format of the GCN/IPN_SEG e-mail messages sent to all GCN sites. The format is of the form "TOKEN: value(s)" on each line. This format is a reasonable compromise between human readable and machine readable/parsable formats. A more detailed explanation of the contents of this notice type is given after this example.
TITLE: GCN/IPN/HUNTSVILLE LOCALIZATION NOTICE_TYPE: Final (based on the Huntsville AD Report location) NOTICE_DATE: Tue Feb 10 02:09:09 GMT 1998 TRIGGER_NUM: 6593 GRB_DATE: 98/02/08 GRB_TIME: 12:50:59.93 UT BACO_RA: 55.38d {+03h 41m 31s} (J2000) BACO_DEC: -72.28d {-72d 17' 01"} HUNT_RA: 61.09d {+04h 04m 21s} (J2000) HUNT_DEC: -75.50d {-75d 29' 45"} HUNT_ERR: 1.63 [degees radius, statistical only] B_H_DELTA: 3.57 [deg] HUNT_SC_AZ: 301.30 [deg] HUNT_SC_EL: -22.20 [deg] {Zen_angle=112.20} SUN_POSTN: 321.98d {+21h 27m 54s} -14.95d {-14d 57' 09"} (Current) SUN_B_DIST: 76.80 [deg] MOON_POSTN: 106.91d {+07h 07m 38s} +18.25d {+18d 14' 44"} (Current) MOON_B_DIST: 96.81 [deg] ANNULUS_RA: 344.6931d {+22h 58m 46s} (J2000) ANNULUS_DEC: -12.2244d {-12d 13' 27"} ANNULUS_RADIUS: 74.510 [deg] ANNULUS_WIDTH: 0.072 [deg] (Total width) COMMENTS: GRB. SINGLE PULSE. COMPLEX. STARTS AT ABOUT T-10S. COMMENTS: DURATION ABOUT 50S. COMMENTS: VISIBLE ABOVE 300 KEV. This IPN localization is preliminary. The "total width" of the annulus was selected to include all known uncertainties and systematics. The final analysis will reduce this width. All follow-up queries should be addressed to Kevin Hurley (UC Berkeley, khurley@sunspot.ssl.berkeley.edu). The center of the IPN annulus is tabulated below along the segment that intersects the Huntsville error circle. The Distance column is the sky-angle distance between the Huntville location and the sampled position on the arc segment. The position of maximum probability plus the 1-, 2-, & 3-sigma containment probabilities (statistical+systematic) are marked. A detailed description of the format, content, and meaning of this document is given in the URL: http://gcn.gsfc.nasa.gov/gcn/ipn.html (J2000) RA DEC Distance 54.194 -80.169 4.88 <=== +3-sigma probability 54.347 -80.089 4.80 54.498 -80.009 4.71 54.649 -79.927 4.63 54.799 -79.844 4.54 54.948 -79.760 4.45 55.096 -79.675 4.36 55.243 -79.588 4.27 55.389 -79.501 4.18 55.535 -79.413 4.09 55.679 -79.323 4.00 55.823 -79.233 3.90 55.965 -79.141 3.81 56.106 -79.048 3.71 56.247 -78.954 3.61 56.386 -78.859 3.51 56.525 -78.763 3.42 56.662 -78.666 3.31 56.798 -78.567 3.21 <=== +2-sigma probability 56.933 -78.467 3.11 57.067 -78.366 3.01 57.200 -78.264 2.90 57.332 -78.161 2.79 57.463 -78.057 2.69 57.592 -77.951 2.58 57.720 -77.845 2.47 57.847 -77.737 2.36 57.973 -77.628 2.25 58.098 -77.518 2.13 58.222 -77.406 2.02 58.344 -77.294 1.91 58.465 -77.180 1.79 58.585 -77.065 1.67 58.703 -76.949 1.56 <=== +1-sigma probability 58.820 -76.832 1.44 58.936 -76.714 1.32 59.051 -76.594 1.20 59.164 -76.474 1.08 59.276 -76.352 0.96 59.387 -76.229 0.84 59.497 -76.105 0.72 59.605 -75.980 0.60 59.712 -75.853 0.49 59.817 -75.726 0.39 59.922 -75.597 0.31 60.025 -75.468 0.27 60.126 -75.337 0.29 <=== Max probability 60.226 -75.205 0.37 60.325 -75.073 0.47 60.423 -74.939 0.59 60.519 -74.804 0.71 60.614 -74.668 0.84 60.708 -74.531 0.97 60.800 -74.393 1.11 60.892 -74.254 1.25 60.981 -74.114 1.39 61.070 -73.973 1.53 61.157 -73.831 1.67 <=== -1-sigma probability 61.243 -73.688 1.81 61.327 -73.544 1.96 61.411 -73.400 2.10 61.493 -73.254 2.25 61.573 -73.107 2.40 61.653 -72.960 2.54 61.731 -72.812 2.69 61.808 -72.663 2.84 61.884 -72.513 3.00 61.958 -72.362 3.15 62.031 -72.210 3.30 <=== -2-sigma probability 62.104 -72.058 3.45 62.174 -71.905 3.61 62.244 -71.751 3.76 62.313 -71.596 3.92 62.380 -71.441 4.08 62.446 -71.285 4.23 62.511 -71.128 4.39 62.575 -70.971 4.55 62.637 -70.812 4.71 62.699 -70.654 4.87 62.760 -70.494 5.03 <=== -3-sigma probability -------------------------------- THE END --------------------------------
Details of the content of the IPN_SEGMENT E-mail: GCN/IPN/Huntsville GRB Location Notices Ver: 10 Apr 95 SDB Attached above is an example of a new capability of GCN. GCN is distributing the GRB localizations determined by the Interplanetary Network (IPN). Kevin Hurley is the PI for the IPN operation. Since IPN localizations depend on the Ulysses spacecraft (and the GRO-BATSE instrument), the time delays between the GRB and these notices will be in the 1 to 3 day time range (when we eventually get all the procedures down). Clearly, this is much different than the "few seconds" delays of the BATSE-Original Notices, but the idea is to provide a global service within the GCN network of sites and operations. This service will allow for a more speedy analysis of the appropriate sub-region in observations made by wide FOV instruments. Also, the already existing GCN distribution network will allow for more timely follow-up observations by instruments that have small FOVs (comparable to IPN arc segments). And in late '96, the IPN network be able to produce small boxes, instead of annuli segments, when the Russian Mars 96 spacecraft comes online. The format of the GCN/IPN notices will be: (1) A header of the pertinant numbers (in the standard GCN e-mail notice style) suitable for easy parsing by programs. The GCN and HUNTSVILLE locations of the GRB are given along with the angular distance between the two. The Huntsville location is preliminary and may differ slightly from the "final" location that will appear in the BATSE catalog. The position of the Sun & Moon are given plus their separations from the GCN location as a reference for optical observers. There are four fields for the IPN annulus: the RA & Dec of the center of the annulus, the radius of it, and the total width of the annulus. (2) Some comments describing the status/accuracy of this localization and any "special" comments on that specific burst. (3) The arc segment in RA,Dec tabular form. The location along the arc segment that has the maximum probablilty of the GRB location is marked. This position is not a rigorous quantitative determination, but a determination made by a human folding in the locations and sizes of the sizes of the BATSE-LOCBURST and HUNTSVILLE error circles. While every effort will be made to choose this location correctly, it should be used by observers only as a guide in making their follow-up observations. Eventually, I would like to be able to mark the table with plus and minus 3 sigma points which can also be used as a guide. Down the road, it may be possible to distribute all of this location information in graphical form via postscript files (or similar). Fields Descriptions: TITLE: GCN/IPN/HUNTSVILLE LOCALIZATION or GCN/IPN LOCALIZATION It depends on how much information went into the solution. NOTICE_TYPE: Original or Final The "Original" notices contain only the BATSE-Original location and the 1-sec BATSE DISCLA data light curve to cross- correlate witht he Ulysses lightcurve data. At a later time, the finer time-resolution BATSE data is available for the lightcurve cross-correlation and the Huntsville BATSE team GRB location is available for the "Final" notice. TRIGGER_NUM: This is a number assigned by the on-board BATSE flight software. It sequentially and uniquely identifies each trigger. DATE_TIME: The starting year/month/day hour:minute:second (UT) of the GRB as determined by BATSE. BACO_RA: BACO_DEC: The BACODINE GRB RA & Dec location: in decimal degrees; xxx.xx {0.00 to 359.99} +/-xx.xx {-90.00 to +90.00} The RA= HHh MMm SSs Dec= DDd MM' SS" format is included, so that humans need not repeat a tedious calculation. HUNT_RA: HUNT_DEC: The Huntsville GRB location (Final notices only). B_H_DELTA: The separation between the BACODINE & Huntsville locations. (Final notices only). HUNT_SC_AZ: HUNT_SC_EL: The Huntsville location in GRB Spacecraft Az,El coordinates: in decimal degrees; xxx.xx {0.00 to 359.99}. in decimal degrees; +/-xx.xx {-90.00 to +90.00}. The Zenith angle (90-El) is given as a convenience for the two z-axis instruments. (Final notices only). SUN_POSTN: SUN_B_DIST: MOON_POSTN: MOON_B_DIST: Sun & Moon Positions: There are four fields which give the RA,Dec locations (current epoch) of the Sun & the Moon and their angular distance from the burst location (in decimal degrees). The Sun & Moon locations are also given in HMS,d'" notation as well. The Sun position is accurate to +/-0.01 deg. The Moon location is accurate to +/-1 deg. These fields are a convenience to the human recipients who are planning follow-up observations. ANNULUS_RA: ANNULUS_DEC: ANNULUS_RADIUS: ANNULUS_WIDTH: The RA,Dec center of the IPN anulus: in decimal degrees; xxx.xx {0.00 to 359.99} +/-xx.xx {-90.00 to +90.00} The RA= HHh MMm SSs Dec= DDd MM' SS" format is included. The radius of the anulus in decimal degrees, and the total width of the anulus; where total width means that it is assigned to include statistical and all known systematic errors. COMMENTS: A brief description of the burst. It can be multiple lines. Typically, the duration and something about the light curve structure ("one peak", "multiple peaks", "FRED", etc).
Shown below are two full-format email examples of the two subtypes:
(Note the contents are somewhat constructed to show the variety
of the data product -- do not take these values as real GRBs.)
===================== A Timestamp-only Notice Example ======================= TITLE: GCN/IPN ANNULUS NOTICE NOTICE_DATE: Sun 24 Aug 08 16:48:40 UT NOTICE_TYPE: IPN Time_only TRIGGER_NUM: 0 GRB_DATE: 14701 TJD; 236 DOY; 08/08/23 GRB_TIME: 31339.25 SOD {08:42:19.25} UT IPN_CENTER_RA: 0.0000d {+00h 00m 00s} (J2000) IPN_CENTER_DEC: +0.0000d {+00d 00' 00"} (J2000) IPN_RADIUS: +0.0000d IPN_WIDTH: +0.0000d = 0.00 [arcmin] = 0.00 [arcsec] IPN_WINDOW: 0.02 [sec] EVENT_DUR: 32.00 [sec] SUN_POSTN: 153.88d {+10h 15m 31s} +10.81d {+10d 48' 19"} SUN_DIST: 151.76 [deg] MOON_POSTN: 68.92d {+04h 35m 41s} +26.94d {+26d 56' 12"} MOON_DIST: 71.18 [deg] COMMENTS: IPN annulus notice. COMMENTS: This notice contains only a timestamp -- the RA,Dec,Radius,Width fields are undefined. COMMENTS: This is definitely a GRB. COMMENTS: The Suzaku-WAM instrument contributed to this notice. ===================== An Annulus Notice Example ============================= TITLE: GCN/IPN ANNULUS NOTICE NOTICE_DATE: Thu 21 Aug 08 05:03:30 UT NOTICE_TYPE: IPN Annulus TRIGGER_NUM: 1234 GRB_DATE: 14699 TJD; 234 DOY; 08/08/21 GRB_TIME: 7226.27 SOD {02:00:26.27} UT IPN_CENTER_RA: 75.409d {+05h 01m 38s} (J2000) IPN_CENTER_DEC: +55.199d {+55d 11' 56"} (J2000) IPN_RADIUS: +54.8501d IPN_WIDTH: +0.2202d = 13.21 [arcmin] = 792.36 [arcsec] IPN_WINDOW: n/a [sec] EVENT_DUR: 22.19 [sec] SUN_POSTN: 150.67d {+10h 02m 41s} +11.99d {+11d 59' 22"} SUN_DIST: 148.40 [deg] MOON_POSTN: 18.71d {+01h 14m 50s} +13.01d {+13d 00' 47"} MOON_DIST: 22.54 [deg] COMMENTS: IPN annulus notice. COMMENTS: This is definitely a GRB. COMMENTS: The Suzaku-WAM instrument contributed to this notice. COMMENTS: The Konus-Wind instrument contributed to this notice.
Details of the content of the IPN_RAW E-mail: The "trig_num" is some mission-specific identification number. It is optional; not all missions-instruments have an identification number. The "grb_date" is the Truncated Julian Day of the burst trigger, eg. TJD=13370 is 01 Jan 2005. The "grb_time" is the UT seconds-of-day (SOD) of the burst trigger. The "ipn_center_ra" & "ipn_center_dec" are the RA,Dec coordinates of the center of the IPN annulus (J2000). This field is valid only if the "trigger_id" 2^0 bit is a 0. The "ipn_radius" is the radius to the center of the IPN annulus. This field is valid only if the "trigger_id" 2^0 bit is a 0. The "ipn_width" is the 3-sigma width of the IPN annulus. The units are 0.0001-degrees (ie the fl.pt. error was multiplied by 10000 and then integerized). This field is valid only if the "trigger_id" 2^0 bit is a 0. The "ipn_window" is the amount of time slop that the Timestamp could vary depending on the direction of the burst wavefront (eg for a LEO s/c, this would be +-0.022 sec, and for Mars Observer, it would range from +/-250 sec to +/-1250 sec depending on the relative positions of Mars and Earth). The "event_duration" is the duration of the event in the specified instrument (see Misc flag bits). (Note that the different mission-instruments have different sensitivities and energy windows, so for a given GRB, there will be variations in this value from one instrument to the next.)
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