TO: All GCN Sites RE: A New GCN Notice type from the Interplanetary Network DT: 18 Sep 00 INTRODUCTION This is to announce the addition of the GCN/IPN_POSITION Notices to the GCN system. These Notices are different from the IPN_ANNULUS and IPN_SEGMENT Notices, in that they are true error-box locations; not annulii or segments of annulii. The GCN/IPN_POSITION Notices are burst locations produced from a 3 (or more) spacecraft triangulation. Up to now, IPN positions have been sent out in the free-format GCN Circulars. Now, they will also be sent out in the GCN standard tokenized format which is suitable for human consumption and computer parsing. BACKGROUND The IPN has been operating in the past with two distant spacecraft, NEAR and Ulysses. However, contacts with the NEAR spacecraft have been on a weekly basis, and much of the burst data has been received too late for rapid follow-up work. This changed in Dec 1999, when NEAR approached the asteroid Eros -- there is daily data recovery for the remainder of the mission (through Feb 2001 at least). The IPN will therefore have not only NEAR and Ulysses, but also the near-Earth spacecraft WIND, BeppoSAX, and HETE-II, all of which should be able to transmit GRB data to Earth within one day or so of detection. In APRIL 2001, the launch of Mars Surveyor Orbiter is expected, which will once more complete the network. THE IPN-to-GCN PROCEDURE Part of the current GCN system automatically captures the burst data from the WIND & NEAR missions and sends it to Kevin Hurley (UC Berkeley). At UCB, these data are combined with the Ulysses data to form true error-box locations. The generation of these locations is done semi-automatically, on a case-by-case basis. After the location is generated, it is sent to the GCN system for distribution to those sites requesting the information. EXPECTED PERFORMANCE Based on past results, we expect to be able to triangulate 1 - 2 GRBs/week with the 3 spacecraft IPN. The error box sizes will be in the 10 sq.arcminute range and above. We will make every effort to obtain these localizations as rapidly as possible, and circulate them via the GCN, as we have been doing in the past. For somewhat less than half the IPN localizations, there will be only 3 spacecraft. This means that without any other location information (e.g. ecliptic latitude from KONUS), there will be two error box locations. Both boxes will be listed in the Notice. For the rest of the IPN Notices, there will be only a single error box. NOTICE CONTENT: As mentioned above, these new GCN/IPN_Position Notices will be in the standard GCN "TOKEN: value" format. Examples of both the single-box and double-box GCN/IPN Notices are appended below. While the details of the contents of these Notices is discussed in the URL below, there are a few items worth mentioning here. The IPN serial number ("IPN_NUMBER: nnn") will have gaps in the sequence and will not be the same for the updated postion Notices issued for the same burst. This number counts the IPN calculations, not the burst. The error given for the position ("GRB_ERROR: 21.28 [arcmin radius, 3 sigma]") is the radius of the circle that circumscribes the entire 4-corner box listed. Because some sites filter Notices based on the size of the position uncertainty, it is necessary to assign a single value of error to each burst position. Even though these boxes will be diamond-shapped in general, the most appropriate single-value for the uncertainty is the radius of a circumscribing circle. THE DETAILS This announcement notice gives a brief description of the new Notice type and how it can be used. The full details are listed in the URL: http://gcn.gsfc.nasa.gov/gcn/ipn.html YOUR ACTION REQUIRED If you wish to receive these GCN/IPN_POSITION Notices (by any of the usual distribution methods: email, sockets, cell phones or pagers), please send a request to Scott Barthelmy (scott@lheamail.gsfc.nasa.gov). As with all the GCN Notice types, filtering can be used on a per-site basis to select which IPN_POSITION Notices you will receive. [Please note that two new filtering criteria were recently added that allow the site to filter on error box size and on time delay.] POSTSCRIPT: HETE2 is scheduled to launch 06 Oct 2000. The final effort is underway to complete the process to distribute GCN/HETE Notices. And announcment will be forthcoming describe what these Notices will be and the usual opportunity to sign up for receiving this additional new Notice type. ======================================================= TITLE: GCN/IPN POSITION NOTICE NOTICE_DATE: Sat 16 Sep 00 20:47:09 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' 37"} (J2000), -17.1622d {-17d 09' 43"} (current), -17.0218d {-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 of circumscribing circle, 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: A GCN Circular is also being issued. ======================================================= ======================================================= TITLE: GCN/IPN POSITION NOTICE NOTICE_DATE: Sat 16 Sep 00 20:46:46 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' 37"} (J2000), -17.1622d {-17d 09' 43"} (current), -17.0218d {-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: 134.3429d {+08h 57m 22s} (J2000) GRB_IPN2_DEC: -8.8224d {-08d 49' 20"} (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 of circumscribing circle, 3 sigma] GRB_BOX_AREA: 196 [sq.arcmin] GRB_PEAK_FLUX: 2.7e-06 [erg/cm2/sec in 25-100 keV] in a 0.50 sec interval GRB_FLUENCE: 3.9e-05 [erg/cm2 in 25-100 keV] 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: A GCN Circular is also being issued. =======================================================