//////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2536 SUBJECT: GRB 040228 (=H3066?,=H3067?): A Long GRB Localized by the HETE-2 WXM DATE: 04/02/28 05:29:49 GMT FROM: Don Lamb at U.Chicago Y. Nakagawa, G. Ricker, J-L. Atteia, N. Kawai, D. Lamb, and S. Woosley, on behalf of the HETE Science Team; T. Donaghy, E. Fenimore, M. Galassi, C. Graziani, M. Matsuoka, T. Sakamoto, R. Satoh, Y. Shirasaki, M. Suzuki, T. Tamagawa, K. Torii, Y. Urata, T. Yamazaki, Y. Yamamoto, and A. Yoshida, on behalf of the HETE WXM Team; N. Butler, G. Crew, J. Doty, A. Dullighan, G. Prigozhin, R. Vanderspek, J. Villasenor, J. G. Jernigan, A. Levine, G. Azzibrouck, J. Braga, R. Manchanda, and G. Pizzichini, on behalf of the HETE Operations and HETE Optical-SXC Teams; M. Boer, J-F Olive, J-P Dezalay, C. Barraud, and K. Hurley, on behalf of the HETE FREGATE Team; report: At 00:08:55.95s UTC (535.95s UT) and 00:12:44.08s UTC (764.08s UT) on 2004 February 28, the HETE-2 FREGATE instrument detected triggers H3066 and H3067. H3066 is a multi-peaked burst with a duration of ~40s in the FREGATE 7-80 and 30-400 keV energy bands; no significant emission associated with H3066 is seen in the WXM 2-25 keV energy band or in the FREGATE 7-40 keV energy band. H3067 consists of a single peak with a duration of ~10 seconds in the FREGATE 30-400 keV energy band; again, no significant emission associated with H3067 is seen in the WXM 2-25 keV energy band or in the FREGATE 7-40 keV energy band. At ~00:13:24 UTC (~800 UT) (~40 seconds after trigger H3067), an X-ray pulse with a duration of >50 seconds is visible in the WXM 2-15 keV energy band. Ground analysis of the WXM data produced a localization that was reported in a GCN Notice at 02:22:44 UT. The WXM localization can be expresssed as a 90% confidence rectangle whose center is at WXM-ground: RA = +10h 12m 12s, Dec = -07d 19' 33" (J2000), and whose corners lie at WXM-ground: RA = +10h 12m 55.6s, Dec = -7d 48' 36" RA = +10h 11m 29.3s, Dec = -7d 47' 46" RA = +10h 11m 28.8s, Dec = -6d 50' 35" RA = +10h 12m 55.4s, Dec = -6d 51' 22" (J2000). The spectrum of the X-ray pulse is such that, had it been detected alone, it would be classified as an XRF. However, the temporal coincidence with the two preceding triggers suggests that the X-ray pulse may be associated with them, and is in fact a soft late phase of the GRB. Because we are unable to localize either H3066 or H3067, we are unable to confirm this possibility at this time. An IPN localization of either H3066 or H3067 could help to resolve the situation, and to determine whether H3066, H3067, and the X-ray pulse are all part of the same burst or not. Light curves for H3066, H3067, and the X-ray pulse, and a skymap showing the localization of the X-ray pulse is provided at the following URL: http://space.mit.edu/HETE/Bursts/GRB040228. //////////////////////////////////////////////////////////////////////// TITLE: GCN/HETE BURST POSITION NOTICE NOTICE_DATE: Sat 28 Feb 04 00:08:59 UT NOTICE_TYPE: HETE S/C_Alert TRIGGER_NUM: 3066, Seq_Num: 1 GRB_DATE: 13063 TJD; 59 DOY; 04/02/28 GRB_TIME: 535.95 SOD {00:08:55.95} UT TRIGGER_SOURCE: Trigger on the 25-400 keV band. GAMMA_RATE: 162 [cnts/s] on a 0.160 [sec] timescale SC_LONG: 348 [deg East] SUN_POSTN: 340.36d {+22h 41m 26s} -8.29d {-08d 17' 28"} MOON_POSTN: 65.06d {+04h 20m 15s} +23.55d {+23d 32' 43"} MOON_ILLUM: 49 [%] COMMENTS: No s/c ACS pointing info available yet. COMMENTS: Probable GRB. ////////////////////////////////////////////////////////////////////// TITLE: GCN/HETE BURST POSITION NOTICE NOTICE_DATE: Sat 28 Feb 04 00:13:13 UT NOTICE_TYPE: HETE S/C_Alert TRIGGER_NUM: 3067, Seq_Num: 1 GRB_DATE: 13063 TJD; 59 DOY; 04/02/28 GRB_TIME: 764.08 SOD {00:12:44.08} UT TRIGGER_SOURCE: Trigger on the 25-400 keV band. WXM_SIG/NOISE: 0.1 sig/noise on a 6.720 [sec] timescale SC_-Z_RA: 160 [deg] SC_-Z_DEC: 9 [deg] SC_LONG: 2 [deg East] SUN_POSTN: 340.36d {+22h 41m 26s} -8.29d {-08d 17' 24"} MOON_POSTN: 65.10d {+04h 20m 23s} +23.55d {+23d 33' 10"} MOON_ILLUM: 49 [%] COMMENTS: Probable GRB. ////////////////////////////////////////////////////////////////////// TITLE: GCN/HETE BURST POSITION NOTICE NOTICE_DATE: Sat 28 Feb 04 00:17:03 UT NOTICE_TYPE: HETE S/C_Last TRIGGER_NUM: 3067, Seq_Num: 2 GRB_DATE: 13063 TJD; 59 DOY; 04/02/28 GRB_TIME: 764.08 SOD {00:12:44.08} UT TRIGGER_SOURCE: Trigger on the 25-400 keV band. WXM_SIG/NOISE: 0.1 sig/noise on a 6.720 [sec] timescale SC_-Z_RA: 160 [deg] SC_-Z_DEC: 9 [deg] SC_LONG: 2 [deg East] SUN_POSTN: 340.36d {+22h 41m 26s} -8.29d {-08d 17' 24"} MOON_POSTN: 65.10d {+04h 20m 23s} +23.55d {+23d 33' 10"} MOON_ILLUM: 49 [%] COMMENTS: Probable GRB. COMMENTS: There is no position known for this trigger at this time. ////////////////////////////////////////////////////////////////////// TITLE: GCN/HETE BURST POSITION NOTICE NOTICE_DATE: Sat 28 Feb 04 02:22:44 UT NOTICE_TYPE: HETE Ground Analysis TRIGGER_NUM: 3067, Seq_Num: 3 GRB_DATE: 13063 TJD; 59 DOY; 04/02/28 GRB_TIME: 764.08 SOD {00:12:44.08} UT TRIGGER_SOURCE: Trigger on the 25-400 keV band. WXM_SIG/NOISE: 0.1 sig/noise on a 6.720 [sec] timescale SC_-Z_RA: 160 [deg] SC_-Z_DEC: 9 [deg] SC_LONG: 2 [deg East] WXM_CNTR_RA: 153.051d {+10h 12m 12s} (J2000), 153.103d {+10h 12m 25s} (current), 152.427d {+10h 09m 42s} (1950) WXM_CNTR_DEC: -7.326d {-07d 19' 33"} (J2000), -7.347d {-07d 20' 48"} (current), -7.079d {-07d 04' 43"} (1950) WXM_CORNER1: 153.2320 -7.8100 [deg] WXM_CORNER2: 152.8720 -7.7960 [deg] WXM_CORNER3: 152.8700 -6.8430 [deg] WXM_CORNER4: 153.2310 -6.8560 [deg] WXM_MAX_SIZE: 61.88 [arcmin] diameter WXM_LOC_SN: 9 sig/noise (pt src in image) WXM_IMAGE_SN: X= 3.3 Y= 2.1 [sig/noise] WXM_LC_SN: X= 8.8 Y= 5.1 [sig/noise] SUN_POSTN: 340.36d {+22h 41m 26s} -8.29d {-08d 17' 24"} SUN_DIST: 162.77 [deg] MOON_POSTN: 65.10d {+04h 20m 23s} +23.55d {+23d 33' 10"} MOON_DIST: 91.12 [deg] MOON_ILLUM: 49 [%] GAL_COORDS: 248.91,38.31 [deg] galactic lon,lat of the burst ECL_COORDS: 157.75,-17.21 [deg] ecliptic lon,lat of the burst COMMENTS: Definite GRB. COMMENTS: Burst_Validity flag is true. COMMENTS: WXM data refined since S/C_Last Notice. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2537 SUBJECT: GRB040228 : KISO optical follow-up observation DATE: 04/03/01 01:50:54 GMT FROM: Yuji Urata at RIKEN Y. Sarugaku (JAXA/ISAS), T. Aoki, Y. Urata, K.Y. Huang, and T. Tamagawa on behalf of KISO GRB Team report; "We have observed the entire HETE-2 error region of GRB040228 (Nakagawa et al. GCN2536) with Kiso observatory 1.05 m Schmidt telescope using 2kx2k CCD camera which field of view is 50 x 50 arcmin. We obtained Rc-band data sets (300 sec x 4 frames), starting at Feb. 28 12:11 UT (0.5 days after the burst). The limiting magnitude for each images is about 19.5 mag. Comparison with DSS II red images, no new object was detected down to the limiting magnitude." This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2538 SUBJECT: IPN triangulation of GRB040228 (H3066, H3067) DATE: 04/03/02 01:15:17 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley and T. Cline, on behalf of the Ulysses, HETE, Mars Odyssey, and Konus GRB teams, I. Mitrofanov, S. Charyshnikov, V. Grinkov, A. Kozyrev, M. Litvak, and A. Sanin, on behalf of the HEND-Odyssey GRB team, W. Boynton, C. Fellows, K. Harshman, C. Shinohara and R. Starr, on behalf of the GRS-Odyssey GRB team, E. Mazets and S. Golenetskii, on behalf of the Konus-Wind GRB team, and G. Ricker, J-L Atteia, N. Kawai, D. Lamb, S. Woosley, J. Doty, R. Vanderspek, J. Villasenor, G. Crew, G. Monnelly, N. Butler, J.G. Jernigan, A. Levine, F. Martel, E. Morgan, G. Prigozhin, J. Braga, R. Manchanda, G. Pizzichini, Y. Shirasaki, C. Graziani, M. Matsuoka, T. Tamagawa, K. Torii, T. Sakamoto, A. Yoshida, E. Fenimore, M. Galassi, T. Tavenner, T. Donaghy, M. Boer, J-F Olive, and J-P Dezalay, on behalf of the HETE GRB team, report: Mars Odyssey (HEND and GRS) and Konus-Wind observed H3066 (GRB040228 at 00536 s, GCN 2536). In addition, Konus-Wind observed H3067 (GRB040228 at 00764 s) and the 50 s long X-ray pulse which followed it (GCN 2536). Neither of these was observed by Odyssey, but this is consistent with the lower intensity of H3067, and the spectral softness of the X-ray pulse (the Odyssey lower energy threshold is ~100 keV). Ulysses was off. We have triangulated H3066 to an annulus centered at RA, Decl (J2000) = 222.855, -17.387 degrees, whose radius is 31.387 +/- 0.055 degrees (3 sigma). The minimum distance between this annulus and the position of the X-ray pulse determined by the HETE WXM is ~37 degrees; in addition, this position is Mars-blocked to Odyssey. We therefore conclude that H3066 and the X-ray pulse are unrelated. Using Mars-blocking, the IPN annulus, and the Konus ecliptic latitude determination, we can restrict the arrival direction of H3066 to that portion of the annulus which lies between RA, Dec = 246, -42 degrees, and 253, -33 degrees. This area was far outside the HETE WXM FOV, further proof that H3066 and the X-ray pulse detected by the WXM are unrelated. However, Konus-Wind data indicate that the arrival directions of H3066, H3067, and the X-ray pulse are all consistent with an ecliptic latitude of -10 to -20 degrees. Thus H3067 may be related either to H3066 or to the X-ray pulse (but not both). It may also be an independent event. Finally, we note that the Odyssey data display a strong, 5 s long pulse ~350 s after the signal corresponding to H3066. We are investigating the possible relation of this pulse to the other bursts. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2539 SUBJECT: GRB 040228 Optical observations DATE: 04/03/02 19:12:13 GMT FROM: Holger Pedersen at Copenhagen U Obs H. Pedersen, Copenhagen University Observatory, on behalf of the GRACE team, reports: "The Descartes Optical Telescope, consisting of a parallactically mounted F=24 mm, f/2.8 lens and a 1472 x 2184 pixel CCD (pixel size: 6.8 micron), is currently undergoing tests at ESO, La Silla, during which serendipitous observations of the GRB040228 error box (Nakagawa et al. GCN 2536, see also Hurley et al. GCN 2538) were done on several nights starting February 22 d 1 h UTC. No filter was used, and all exposures lasted 30 s followed by 30 s read-out. During each of the first five nights integrations spanning several hours were obtained under mostly good conditions. No observations were attempted on February 27. On the night of trigger no. H3066 a partial clearing started more than an hour later. A set of 24 exposures obtained in the time interval from 75 to 99 minutes after the trigger are of fairly uniform quality and have been co-added. No candidate afterglow is seen in or near the error box to m(r) = 10.2, based on USNO photometry of U0825_07125568, a star near the centre of the error box. Observations taken in the time interval from 46 to 45 hours prior to the GRB likewise give no indication of 'preglow', to a limit of m(r) = 10.5. All values are preliminary and should not be published before further confirmation."