//////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1332 SUBJECT: Short RXTE/ASM transient 020406; may be a GRB DATE: 02/04/06 22:47:03 GMT FROM: Don Smith at U michigan D. A. Smith (U of Michigan) and A. M. Levine (MIT) report on behalf of the RXTE/ASM teams at MIT and NASA/GSFC: The ASM has detected a hard, brief (>~30 s), bright (peak 5-12 flux ~2 Crab) X-ray flare from a location inconsistent with any known source in the ASM catalog. The event appears to have be a single flare (the ASM scanned off the source before the flux went to zero), beginning at around 2002/04/06 18:18:15 (UTC). The flare was detected in two of the ASM scanning shadow cameras, although the source location was barely 30 arcminutes from the edge of SSC 1, rendering localization difficult in this camera. Nevertheless, we believe the source to be localized to within a parallelogram (with 90% confidence) centered on the coordinates (J2000.0): 19h 00m 24s.29, 01d 24' 49".1 With corners at the following locations: R.A.: 18 59 54.01 19 04 11.18 19 03 45.70 18 59 28.52 Dec.: 01 23 9.06 01 24 55.62 01 27 34.74 01 25 47.48 The characteristics of these observations are similar to other detections of GRBs with the ASM, and so we tentatively designate it as GRB 020406. We await confirmations with higher energy / IPN instruments. //////////////////////////////////////////////////////////////////////// TITLE: GCN/RXTE_ASM BURST POSITION NOTICE NOTICE_DATE: Sat 06 Apr 02 22:51:33 UT NOTICE_TYPE: RXTE-ASM Initial TRIGGER_NUM: No correlation with BATSE is possible. GRB_DATE: 12370 TJD; 96 DOY; 02/04/06 GRB_TIME: 65916.37 SOD {18:18:36.37} UT POSITION_TYPE: Box GRB_RXTE_RA: 285.101d {+19h 00m 24s} (J2000), 285.130d {+19h 00m 31s} (current), 284.467d {+18h 57m 52s} (1950) GRB_RXTE_DEC: +1.414d {+01d 24' 50"} (J2000), +1.417d {+01d 25' 02"} (current), +1.343d {+01d 20' 34"} (1950) GRB_ERROR_RA1: 284.975d {+18h 59m 54s} (J2000) GRB_ERROR_DEC1: 1.386d {+01d 23' 09"} (J2000) GRB_ERROR_RA2: 286.047d {+19h 04m 11s} (J2000) GRB_ERROR_DEC2: 1.415d {+01d 24' 54"} (J2000) GRB_ERROR_RA3: 285.940d {+19h 03m 46s} (J2000) GRB_ERROR_DEC3: 1.460d {+01d 27' 36"} (J2000) GRB_ERROR_RA4: 284.869d {+18h 59m 29s} (J2000) GRB_ERROR_DEC4: 1.430d {+01d 25' 48"} (J2000) GRB_RXTE_ERROR: 0.600 [deg radius (stat+sys), 90%] GRB_RXTE_INTEN: 2000.00 [mCrab] SUN_POSTN: 15.46d {+01h 01m 51s} +6.59d {+06d 35' 34"} SUN_DIST: 90.17 [deg] MOON_POSTN: 314.22d {+20h 56m 53s} -21.32d {-21d 18' 55"} MOON_DIST: 36.40 [deg] COMMENTS: RXTE-ASM GRB Coordinates. COMMENTS: Likely GRB: hard x-ray flare from uncataloged location. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1338 SUBJECT: GRB020406(?), optical observations DATE: 02/04/07 22:25:26 GMT FROM: Arne A. Henden at USNO/USRA D. Durig (ddurig@sewanee.edu) and A. McDermott report on behalf of the International AAVSO GRB Network: We observed the RXTE/ASM error box for the short X-ray transient 020406 (Smith et al. GCN 1332), that may be related to a GRB, with the Cordell-Lorenz Observatory 0.3m telescope and ST-9E/AO-7 CCD system. The western half of the error box was mosaiced with limiting magnitude approximately 20. Near the center of the error box an object was found that does not appear on either the blue or red POSS-II plate. At coordinates: 19:00:42.10 +01:27:22.4 J2000 +/- 0.2s +/- 0.4" this object had an estimated unfiltered magnitude of 18.9 (USNO-A2.0 red) on a 10-minute exposure with midpoint UTD 020407.394 (13hrs after the ASM detection); two subsequent exposures showed fading behavior (19.2 and 19.3mag), but a constant brightness also fits within the photometric errors. No known GCVS variable star nor known asteroid is near this position. As this is a crowded field with no obvious galaxies on the POSS plates, this object may just be an unrelated galactic variable of large amplitude. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1341 SUBJECT: ASM GRB candidate 020406 refined error box DATE: 02/04/08 23:24:57 GMT FROM: Don Smith at U michigan D. A. Smith (U of Michigan) and R. Remillard (MIT) report on behalf of the RXTE/ASM teams at MIT and NASA/GSFC: Further RXTE/ASM detections of the event reported in GCN Circ. No. 1332 have been discovered in the ASM production data, missing from the realtime data stream available on the day of the event. Rather than scanning *off* the source, as we reported, the ASM scan actually moved to put the source *closer* to the center of the FOV, greatly increasing the detector area exposed to this source. The time series data show that the source remained bright, with some evidence for fading, for at least 100 seconds after the end of the observation reported in GCN Circ. 1332. The light curve is strongest in the 5-12 keV band, with an average count rate during the second dwell of 21.3+-0.7 c/s, as compared to only 3.0+-0.6 c/s in the 1.5-3 keV band (ASM rates for the Crab are 25.4 and 26.8 in the soft and hard bands, respectively). Using the strongest detection of this source in each camera, we were able to greatly refine our error box to a parallelogram roughly 3 arcminutes on a side. This box is centered on the coordinates R.A.: 19h 01m 45.95s, Decl: 1d 26' 15.7", and its corners are located at the following coordinates (all coordinates in epoch J2000.0): R.A. Decl. 285.4381 1.4150 285.3389 1.4563 285.4472 1.4595 285.5416 1.4201 This refined localization appears to rule out the counterpart candidate proposed by Durig & McDermott in GCN #1138. A background-subtracted 5-12 keV light curve and the four ASM localizations of this event can be seen at http://xte.mit.edu/grb/grb020406/ //////////////////////////////////////////////////////////////////////// TITLE: GCN/RXTE_ASM BURST POSITION NOTICE NOTICE_DATE: Mon 08 Apr 02 23:32:43 UT NOTICE_TYPE: RXTE-ASM Update TRIGGER_NUM: No correlation with BATSE is possible. GRB_DATE: 12370 TJD; 96 DOY; 02/04/06 GRB_TIME: 65916.37 SOD {18:18:36.37} UT POSITION_TYPE: Box GRB_RXTE_RA: 285.441d {+19h 01m 46s} (J2000), 285.470d {+19h 01m 53s} (current), 284.807d {+18h 59m 14s} (1950) GRB_RXTE_DEC: +1.438d {+01d 26' 17"} (J2000), +1.441d {+01d 26' 29"} (current), +1.365d {+01d 21' 55"} (1950) GRB_ERROR_RA1: 285.438d {+19h 01m 45s} (J2000) GRB_ERROR_DEC1: 1.415d {+01d 24' 54"} (J2000) GRB_ERROR_RA2: 285.339d {+19h 01m 21s} (J2000) GRB_ERROR_DEC2: 1.456d {+01d 27' 22"} (J2000) GRB_ERROR_RA3: 285.447d {+19h 01m 47s} (J2000) GRB_ERROR_DEC3: 1.460d {+01d 27' 36"} (J2000) GRB_ERROR_RA4: 285.542d {+19h 02m 10s} (J2000) GRB_ERROR_DEC4: 1.420d {+01d 25' 12"} (J2000) GRB_RXTE_ERROR: 0.100 [deg radius (stat+sys), 90%] GRB_RXTE_INTEN: 2000.00 [mCrab] SUN_POSTN: 15.46d {+01h 01m 51s} +6.59d {+06d 35' 34"} SUN_DIST: 89.83 [deg] MOON_POSTN: 314.22d {+20h 56m 53s} -21.32d {-21d 18' 55"} MOON_DIST: 36.16 [deg] COMMENTS: RXTE-ASM GRB Coordinates. COMMENTS: Greatly refined error box; see http://xte.mit.edu/grb/grb020406 COMMENTS: for more information //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1351 SUBJECT: GRB020406(?), optical observations DATE: 02/04/10 21:40:53 GMT FROM: Arne A. Henden at USNO/USRA D. Durig and A. McDermott (Cordell-Lorenz) and B. Gary (Santa Barbara) report on behalf of the International AAVSO GRB Network: We observed the RXTE/ASM revised error box for the possible GRB 020406 (Smith et al. GCN 1332, 1341) with the Cordell-Lorenz Observatory 30cm telescope (ST-9E/AO-7 CCD) and Gary 25cm telescope (ST-8E). coverage lim mag UTD entire box CR=17 020407.356 western half CR=20 020407.356 central 80% Rc=17.5 020407.500 remaining 20% Rc=17.1 020407.500 entire box CR=20 020410 Where CR = unfiltered, using R-band zeropoint, and Rc = taken with a standard Cousins R filter. No new objects were found in the revised error box to the limiting magnitudes listed above. In addition, the entire original box was covered to CR=17 on 020407.4 with no new source detected. The candidate mentioned in Durig and McDermott (GCN 1338) was reobserved on 020410 and has shown no fading over the past 72 hours; it can be eliminated as a possible afterglow candidate.