TABLE OF CONTENTS:
The GCN system has been modified to incorporate the distribution
of positions of GRB Counterparts detected by all the other instruments and telescopes.
These are locations of GRB counterparts detected by follow-up observers.
Like all the other sources of GRB information within the GCN system,
users can elect to receive (or not) these COUNTERPART Notices.
The GCN/COUNTERPART Notices are archived within the GCN website
in the Table of COUNTERPART Notices.
Notice Type, Content, and Purpose
There is only one notice type for COUNTERPART.
They are issued only when a follow-up observer detects a counterpart AND submits a notice
via the web page form.
They contain the calculated RA,Dec location of the burst counterpart candidate,
the date and time of the event, and several fields relating to the event:
To submit a Counterpart Notice, you must be in the Circulars list -- this is the vetting process.
The "cntrpart_ra" and "cntrpart_dec" are the RA,Dec coordinates of the burst counterpart.
The "intensity" a measure of the intensity or flux of the counterpart (mag for optical, flux for radio and other).
The "inten_error" field contains the uncertainty (statistical plus systematic)
of the cp_inten value. The units are also centi-magnitudes or centi-uJy or
centi-units for 'other' (eg centi-kHz, centi-MHz, centi-GHz, centi-keV,...,centi-TeV).
(See the 'expo' subfield in the 'filter' value.)
The "cntrpart_error" is the radius of the circle that will contain on average 68% of the events.
The "duration" is the time interval of the search window of the event_times stream
looking for an increase.
The "seeing" field contains the seeing during the observation. The units are centi-arcsec.
The "obs_tjd" is the Truncated Julian Day of the start of the observation.
The "obs_sod" is the Seconds-of-Day of the start of the observation.
The "obs_dur" is the duration in centi-seconds of the observation. The seconds
is multiplied by 100 and then integerized (i.e. the units are centi-sec; 10 msec).
The "id_conf" is the confidence level of the identification of the counterpart to the GRB.
The percentage_value is multiplied by 100 and then integerized (i.e. the units are centi-%).
The "trigger_id" field contains bit_flags which attempt to identify
the type of the counterpart.
The defined flags are:
Bit_Num Item_name Description
------- --------- -----------
0 n/a n/a
1 definite_grb 0=No or 1=Yes, it is definitely a GRB
2 n/a n/a
The "misc" field contains various bit_flags and the message sequence number.
The defined flags are:
Bit_Num Item_name Description
------- --------- -----------
0-4 n/a n/a
5-6 type optical=1/radio=2/other=3
The "tele_name" is 16 bytes to store the ASCII string of the name of the telescope
that made the follow-up observation and counterpart detection.
The name can be 0-15 characters long; it will always be null-terminated.
The "name" is 60 bytes to store the ASCII string of the name of the person
that made the follow-up observation and counterpart detection.
The name can be 0-59 characters long; it will always be null-terminated.
The sequence of activities for a typical burst follows:
1) A burst happens and is deteced by some GRB-detecting space-based instrument.
2) The location of this burst is distributed to the world community by GCN.
3) Some person/group/instrument makes a follow-up observation of the burst error box.
4) They identify a counterpart to that burst.
5) They submit that counterpart locatin to GCN.
6) The Counterpart Notice is distributed to the world community (based on the site's configurations).
Samples of the E-mail, Pager, Short-form Pager, and Subject-only
distribution methods of the GCN/COUNTERPART Notice are included below.
The format is very similar to the other spacecraft-instrument sources
of GRB locations -- the GCN-standard "TOKEN: value" format.
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.
The COUNTERPART Notice is type=45.
Sites can elect to receive the COUNTERPART Notice type.
This filtering applies to all the existing distribution
methods/media (sockets, email, pagers, cell).
The uncertainty in the location will depend on:
(a) the counterpart_intensity,
(b) the waveband the follow-up observation is being made,
(c) the positional accuracy of the intrument/telescope making the follow-up observation,
(d) the seeing (if this is an optical follow-up, which will be most of them).
There is no test_notice version of this COUNTERPART type.
There are several other mission-based test notices within GCN, and
maybe they can fullfill your test notice needs.
Sites are encouraged to acknowledge the site/person and GCN in their publications
that contributed the counterpart notice that your follow-up observations were based on.
For further information on this, please contact
Scott Barthelmy (for GCN issues),
and
these GCN web pages, and
GCN/COUNTERPART GRB table.
Examples of the COUNTERPART Notice type 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 data from the instrument,
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 constant.
The subject-line strings are (respectively):
The 'raw' versions:
GCN/COUNTERPART_GRB_POSITION
/////////////////////////COUNTERPART e-mail format//////////////////////////////
TITLE: GCN/GRB_COUNTERPART POSITION NOTICE
NOTICE_DATE: Wed 07 Oct 06 10:34:46 UT
NOTICE_TYPE: Optical
TRIGGER_NUM: 123456
CNTRPART_RA: 123.4560d {+08h 13m 49.4s} (J2000),
123.4588d {+08h 13m 50.1s} (current),
122.8101d {+08h 11m 14.4s} (1950)
CNTRPART_DEC: +1.2344d {+01d 14' 03.8"} (J2000),
+1.2337d {+01d 14' 01.4"} (current),
+1.3866d {+01d 23' 11.6"} (1950)
CNTRPART_ERROR: 599.8 [arcsec, radius]
GRB_DATE: 14015 TJD; 280 DOY; 06/10/07
GRB_TIME: 36488.81 SOD {10:08:08.81} UT
OBS_DATE: 14015 TJD; 280 DOY; 06/10/07
OBS_TIME: 36518.00 SOD {10:08:38.00} UT
OBS_DUR: 10.0 [sec]
MAG: 16.5 +/- 1.0
FILTER: U
SEEING: 1.5 [arcsec]
TELESCOPE: ROTSE
SUBMITOR: Eli_Rykoff
SUN_POSTN: 202.82d {+13h 31m 16s} -9.54d {-09d 32' 34"}
SUN_DIST: 79.72 [deg] Sun_angle= 5.3 [hr] (West of Sun)
MOON_POSTN: 162.75d {+10h 51m 01s} +8.81d {+08d 48' 28"}
MOON_DIST: 39.84 [deg]
MOON_ILLUM: 14 [%]
GAL_COORDS: 221.51, 18.83 [deg] galactic lon,lat of the counterpart
ECL_COORDS: 125.46,-18.18 [deg] ecliptic lon,lat of the counterpart
COMMENTS: GRB COUNTERPART Coordinates.
////////////////////////////////////////////////////////////////////////////
Examples 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.
/////////////////////////COUNTERPART Pager format////////////////////////////// GCN/COUNTERPART Optical RA=218.27d DEC=+59.36d ERR=0.5deg TIME: 23:05:12.83 UT MAG=16.5 +/- 1.0 FILTER=U SEEING=1.5 [arcsec] ///////////////////////////////////////////////////////////////////////////
Examples 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.
[i need to fill in the rest of these examples!!!] /////////////////////////COUNTERPART Short-Pager format///////////////////////// ////////////////////////////////////////////////////////////////////////////
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:
[i need to fill in these examples!!!] /////////////////////////COUNTERPART Subject-only format///////////////////////// ///////////////////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////////////////////////////