[vsnet-grb 92965] GCN/Fermi-LAT_Update Notices available
Bacodine
vxw at capella.gsfc.nasa.gov
Sun Mar 1 07:52:34 JST 2009
TO: All GCN Notice recipients
RE: Fermi-LAT_Update_Position Notice type is available
DT: 28 Feb 09
INTRODUCTION:
The GCN system has been modified to incorporate the distribution
of positions of GRBs detected by the LAT instrument on the Fermi spacecraft.
These LAT-based Notices are the results of on-board (realtime) processing.
They are called the LAT_Update Notice type.
(There are 2 other LAT-based Notice types, but they are not ready
for public distribution - they may be announced later.)
About 5 times per year, the flight software in LAT will detect a burst.
The time delays for the LAT_Update are in the 10-20 sec range.
The location uncertainties are in the 10-100 arcmin range.
ACTION ITEM:
If, after reviewing the information below, you want to receive
these Fermi-LAT_Update Position notices, please send me a request
to have them enabled. You can do this by forwarding this email to
scott at milkyway.gsfc.nasa.gov .
(You can also request changes to any part of your configuration.
A reminder: Fermi-GBM notice types were added back in Oct 2008,
the SIMBAD_NED search_results notice type in Aug 2008, and
AGILE notice types in July 2008.)
NOTICE TYPES, CONTENT, and PURPOSE:
There are 3 LAT Notice types. (Currently, only the "Update" type is being
made available by the Fermi-LAT Team for public distribution.) They are:
1) LAT_Initial Position Notice contains the position using the initial
(smallest) portion of the data.
They are issued 1 time per trigger.
This type is not yet available for public distribution.
2) LAT_Update Notice contains the RA,Dec location for the burst detected by LAT.
They are calculated by the on-board Flight software.
They are issued 6 times per burst.
Currently ONLY the 2nd of these Updates is available for public distribution.
The rationale for this choice of public distribution or not is a trade
between the amount of source photons collected and background photons collected.
The LAT Team decided that this "2nd Update" notice contains, on average,
the best balance of signal and noise.
3) LAT_Ground_Refined_Position Notice contains the RA,Dec location
for the burst detected by LAT.
The positions are calculated by automated ground software 4-6 hours
after the burst trigger. More sophisticated algorithms are applied
to the data to improve the location accuracy.
There can be 0, 1, or more instances of this Notice Type per trigger.
This type is not yet available for public distribution.
4) Test Notice is identical in format and content to the 3 Position Notices
except that the Test Notices contain computer-generated RA,Dec locations and
all the other fields.
These Test Notices are generated by the GCN computer every ~3.6 hrs.
They allow the receiving site to practice on the Position Notice types.
This LAT_Test type has been available for many months.
ERRORS and TIME_DELAYS:
The timescales and localization precisions of the various notice types
are as follows:
TIME SINCE LOCATION
TYPE BURST ACCURACY COMMENTS
========= ============ ========== ========
Initial 2-4 sec 10-100 arcmin On-board processing (Not public)
Update 2-32 sec 10-100 arcmin On-board processing (2nd of 6 is public)
Gnd_Refined 4-6 hrs 5-30 arcmin Ground processing (Not yet public)
GRB CONFIDENCE LEVEL:
The LAT Team has also required that only those LAT_Update_Position notices
that have a summed Temporal_statistic plus Image_statistic greater than 120
will be distributed to the public. This threshold filtering removes
a large number of "noise" triggers. It is expected that the percentage
of these ">120"-Update Notices will be >99.9% real GRBs.
ARCHIVE STORAGE:
The GCN/FERMI Notices are archived within the GCN website
in the Table of FERMI GRBs: http://gcn.gsfc.nasa.gov/gcn/fermi_grbs.html
This archives both the GBM Notice types and the LAT_Update notice type.
MORE INFORMATION:
Can be found at: http://gcn.gsfc.nasa.gov/gcn/fermi.html
NOTICE EXAMPLE:
Here is an example of a full-format email LAT_Update Position Notice:
TITLE: GCN/FERMI NOTICE
NOTICE_DATE: Tue 17 Feb 09 04:57:02 UT
NOTICE_TYPE: Fermi-LAT Update Position
RECORD_NUM: 2
TRIGGER_NUM: 256539404
GRB_RA: 214.417d {+14h 17m 40s} (J2000),
214.536d {+14h 18m 09s} (current),
213.764d {+14h 15m 03s} (1950)
GRB_DEC: -4.383d {-04d 22' 59"} (J2000),
-4.425d {-04d 25' 30"} (current),
-4.153d {-04d 09' 09"} (1950)
GRB_ERROR: 57.00 [arcmin radius, statistical only]
GRB_INTEN_TOT: 18 [cnts]
GRB_INTEN1: 7 [cnts] (0-100 MeV)
GRB_INTEN2: 6 [cnts] (0.1-1 GeV)
GRB_INTEN3: 3 [cnts] ( 1-10 GeV)
GRB_INTEN4: 2 [cnts] (10-up GeV)
INTEG_DUR: 3.169 [sec]
TRIGGER_INDEX: 0
GRB_DATE: 14879 TJD; 48 DOY; 09/02/17
GRB_TIME: 17805.09 SOD {04:56:45.09} UT
SOLN_STATUS: 0x30000003
TEMP_TEST_STAT: 81.50 (log(prob), time domain)
IMAGE_TEST_STAT: 53.25 (log(prob), image domain)
SUN_POSTN: 330.81d {+22h 03m 14s} -11.94d {-11d 56' 20"}
SUN_DIST: 114.57 [deg] Sun_angle= 7.8 [hr] (West of Sun)
MOON_POSTN: 238.87d {+15h 55m 29s} -25.36d {-25d 21' 40"}
MOON_DIST: 31.36 [deg]
MOON_ILLUM: 47 [%]
GAL_COORDS: 339.67, 52.23 [deg] galactic lon,lat of the burst (or transient)
ECL_COORDS: 213.65, 8.86 [deg] ecliptic lon,lat of the burst (or transient)
COMMENTS: Fermi-LAT Coordinates.
COMMENTS: The BurstID came from GBM.
The socket packets contents can be found at:
http://gcn.gsfc.nasa.gov/gcn/sock_pkt_def_doc.html
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 at lheamail.gsfc.nasa.gov
PAGER: 3013463733 at cingularme.com
WEB: http://gcn.gsfc.nasa.gov/gcn
///////////////////////////// Your Current Configuration ////////////////////////
Site_name: VSNET
Lon,Lat= 135.75 35.00
Distribution_method: EMAIL Attachment_format: NONE
Address: vsnet-grb at ooruri.kusastro.kyoto-u.ac.jp
Filter: ALL
Error_limit= 360.100 [deg, diameter]
Delta_T_limit= 999.900 [hr]
Swift_Trigger_ID_filter: Disabled
Sources & Notice Types/Subtypes:
RXTE-PCA_Alert_wont: Disabled
RXTE-PCA_Alert_will: Disabled
RXTE-PCA_nosaw: Enabled
RXTE-PCA_saw: Enabled
RXTE-ASM: Enabled
IPN_RAW: Disabled
IPN_POS: Enabled
RXTE-ASM_TRANS: Enabled
HETE_TEST: Disabled
TYPE2_TEST: Disabled
INTEGRAL_Test_notices: Disabled
SWIFT_BAT_GRB_TEST: Disabled
AGILE_GRB_TEST: Disabled
FERMI_GBM_TEST: Disabled
FERMI_LAT_TEST: Disabled
INTEGRAL_POINTDIR: Disabled
INTEGRAL_SPIACS: Enabled
INTEGRAL_WAKEUP: Enabled
INTEGRAL_REFINED: Enabled
INTEGRAL_OFFLINE: Enabled
GRB_CNTRPART: Disabled
MILAGRO_POS: Disabled
SWIFT_BAT_GRB_ALERT: enabled
SWIFT_BAT_GRB_POS: enabled
SWIFT_BAT_GRB_POS_NACK: enabled
SWIFT_BAT_SUBTHRESH_POS: Disabled
SWIFT_BAT_GRB_LIGHTCURVE: enabled
SWIFT_FOM_2OBS: enabled
SWIFT_SC_2SLEW: enabled
SWIFT_XRT_POS: enabled
SWIFT_XRT_POS_NACK: enabled
SWIFT_XRT_SPECTRUM: enabled
SWIFT_XRT_IMAGE: enabled
SWIFT_XRT_LIGHTCURVE: enabled
SWIFT_UVOT_IMAGE: enabled
SWIFT_UVOT_SRCLIST: enabled
SWIFT_UVOT_POS: enabled
SWIFT_UVOT_POS_NACK: Disabled
SWIFT_BAT_GRB_LC_PROC: enabled
SWIFT_XRT_SPECTRUM_PROC: enabled
SWIFT_XRT_IMAGE_PROC: enabled
SWIFT_UVOT_IMAGE_PROC: enabled
SWIFT_UVOT_SRCLIST_PROC: enabled
SWIFT_FULL_DATA_INIT: enabled
SWIFT_FULL_DATA_UPDATE: enabled
SWIFT_POINTDIR: enabled
SWIFT_BAT_TRANS: Disabled
SWIFT_BAT_SLEW_POS: Disabled
SWIFT_TOO_FOM: enabled
SWIFT_TOO_SLEW: enabled
AGILE_GRB_WAKEUP_POS: Disabled
AGILE_GRB_GROUND_POS: Disabled
AGILE_GRB_REFINED_POS: Disabled
AGILE_POINTDIR: Disabled
FERMI_GBM_ALERT: Disabled
FERMI_GBM_FLT_POS: Disabled
FERMI_GBM_GND_POS: Disabled
FERMI_LAT_POS_UPD: Disabled
FERMI_POINTDIR: Disabled
SIMBAD-NED: Disabled
General Adminastrivia Comments/Suggestions:
1) When requesting changes to your configuration,
it helps if you refer to your site_name.
2) If your site has more than one recipient (ie a list),
please review the list to see if anybody should be deleted;
(the volume of bounce-back-to-gcn emails gets large after a while).
3) If a new contact_person has taken over for the project, please inform me.
4) If your site is no longer active, please inform me.
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