//////////////////////////////////////////////////////////////////////// From piro@ias.rm.cnr.it Sun May 28 09:17:24 2000 Date: Sun, 28 May 2000 15:10:03 +0200 (DFT) From: "Luigi Piro, BeppoSAX Mission Scientist" To: BEPPOSAX GRB ALERT LIST_2: ; Subject: BeppoSAX mail n.00/10: GRB ALERT: GRB000528 BeppoSAX mail n.00/10: GRB ALERT: GRB000528 On May 28 at 08:46:35 UT a strong and long burst (GRB000528) was detected by GRBM and WFC2 (2-26 keV). The position is: R.A.= 161.354 Decl.= -34.002 with an error radius of 4'. The follow-on is technically feasible, but the unavailability of Mission Planners during Sunday and the switching-off of instruments during weekend nights doesn't allow a useful and fast repointing of satellite (see GCN 634). Giangiacomo Gandolfi on behalf of BeppoSAX Mission Scientist #----------------------------------#------------------------------------------# Luigi Piro | E-mail: Istituto Astrofisica Spaziale | piro@ias.rm.cnr.it C.N.R. | SAX program: saxsci@ias.rm.cnr.it Via Fosso del Cavaliere | phone: -39-06-4993-4007 I-00133 Roma | phone BeppoSAX center: -39-06-4079-6393 Italy | fax(CNR) : -39-06-20660188 #__________________________________#___________________________________________# //////////////////////////////////////////////////////////////////////// From piro@ias.rm.cnr.it Sun May 28 14:23:34 2000 Date: Sun, 28 May 2000 20:17:43 +0200 (DFT) From: "Luigi Piro, BeppoSAX Mission Scientist" To: BEPPOSAX GRB ALERT LIST_2: ; Subject: BeppoSAX MAIL n. 00/11: GRB000528 refined WFC position BeppoSAX MAIL n. 00/11: GRB000528 refined WFC position Refined coordinates from WFC are: R.A.(2000)= 161.276 DEC(2000)= -33.983 i.e. 4' off from the preliminary position. The error radius is 2'. Thanks to BeppoSAX staff personal efforts we are planning a NFI follow-on, with the instruments switched on during the whole night. G. Gandolfi on behalf of BeppoSAX Mission Scientist #----------------------------------#------------------------------------------# Luigi Piro | E-mail: Istituto Astrofisica Spaziale | piro@ias.rm.cnr.it C.N.R. | SAX program: saxsci@ias.rm.cnr.it Via Fosso del Cavaliere | phone: -39-06-4993-4007 I-00133 Roma | phone BeppoSAX center: -39-06-4079-6393 Italy | fax(CNR) : -39-06-20660188 #__________________________________#___________________________________________# //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 674 SUBJECT: GRB 000528 Optical Observations DATE: 00/05/28 23:53:07 GMT FROM: Jens Hjorth at U.Copenhagen GRB 000528 Optical Observations B. L. Jensen, J. Hjorth, H. Pedersen (University of Copenhagen), J. Gorosabel (DSRI), J. A. L. Aguerri (IAC), and A. A. Kaas (NOT) report on behalf of a larger European collaboration: "We have imaged the error circle of GRB 000528 (Piro & Gandolfi, BeppoSAX Mail ## 00/10, 00/11) with the 2.5-m Nordic Optical Telescope. Two 300-s R-band exposures were obtained with ALFOSC on 28.90 May 2000 UT. The data were obtained at high (2.7) airmass but in fairly good seeing (1.4" FWHM) and reach a limiting magnitude of about R = 22.3. No obvious candidate optical counterpart to GRB 000528 is found down to a limit of R ~ 21.5 by comparison with the Digitized Sky Survey (DSS-2, AAO SES red). The NOT image is posted at http://www.astro.ku.dk/~brian_j/grb/grb000528/ ." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 675 SUBJECT: GRB000528: BeppoSAX GRBM observations DATE: 00/05/29 07:31:16 GMT FROM: Filippo Frontera at ITESRE CNR C. Guidorzi, E. Montanari, F. Frontera (Department of Physics, University of Ferrara, Italy) and M. Feroci (IAS/CNR, Rome) on behalf of a larger collaboration report: "With reference to the GRB000528 occurred on May 28.366 UT and localized with the BeppoSAX WFC no. 2 (see BeppoSAX Mails ## 00/10 and 00/11), a preliminary analysis of the GRBM data shows a complex time profile of this GRB with two main peaks of decreasing intensity. The peak flux is of 1.7E3 cts/s in the 40-700 keV energy band corresponding to 1.44 +/- 0.04) x 10^(-6) erg/cm2/s . The GRB duration is of about 80 s. A preliminary spectral analysis reveals an evident softening evolution with an average power law photon index of about 1.9. We are now able to derive rough GRB positions from the GRBM data. The GRBM position obtained for this GRB is R.A.(2000)= 160 and DEC(2000) = -29 with an error radius of 5 deg, that is fully consistent with that given with the WFC." This message is citable. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 677 SUBJECT: GRB 000528 - WFC measurements DATE: 00/05/29 15:30:36 GMT FROM: Jean int Zand at SRON J. in 't Zand and J. Heise, Space Research Organization of the Netherlands (SRON), Utrecht; E. Kuulkers, SRON and Astronomical Institute, Utrecht University; G. D'Andreta and G. Celidonio, BeppoSAX Science Operations Center, Telespazio, Rome; J.M. Muller, SRON and BeppoSAX Science Data Center, Telespazio, Rome; G. Gandolfi and E. Costa, Istituto di Astrofisica Spaziale, CNR, Rome; and F. Frontera, Istituto Tecnologie e Studio Radiazioni Extraterrestri, Bologna, report: "GRB 000528, which was detected by the BeppoSAX Gamma-Ray Burst Monitor on May 28.366 UT (GCN Circ. 675), was simultaneously detected with Wide Field Camera (WFC) unit 2. While the burst lasted for about 80 s in gamma-rays (40-700 keV), it lasted about 120 s in x-rays (2-26 keV). The WFC-determined position is R.A. = 10h45m06.3s, Decl. = -33o58'59" (equinox 2000.0), with an error radius of 2' (99-percent confidence level). The 2-26 keV peak flux is 1.9 Crab units." //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 681 SUBJECT: IPN localization and time history of GRB000528 DATE: 00/05/30 20:51:09 GMT FROM: Kevin Hurley at UCBerkeley/SSL K. Hurley, on behalf of the Ulysses GRB team, T. Cline and E. Mazets, on behalf of the Konus-Wind GRB team, and F. Frontera, C. Guidorzi, and E. Montanari, on behalf of the BeppoSAX GRBM team, report: Ulysses, Konus, and the BeppoSAX GRBM observed this burst (GCN #677). Triangulation gives a preliminary annulus centered at RA(2000)=129.532, Decl.(2000)=-33.150, with radius 26.478 +/- 0.111 degr. (3 sigma). This annulus intersects the BeppoSAX WFC error circle at two points (RA, Decl.=161.292, -34.013, and RA, Decl.=161.283, -33.950), reducing its area by over a factor of two. A map has been posted at ssl.berkeley.edu/ipn3/000528. This localization can be improved. In addition, we call attention to the fact that the Ulysses data clearly show a second episode of emission which follows the burst by ~600 seconds, with intensity approximately as great as that in the burst itself. It is possible that this is from the same source as the burst; we are investigating whether the Konus or GRBM data can be used to verify this. The time history has been posted at the same site. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 683 SUBJECT: GRB000528: BeppoSAX NFI follow-up preliminary analysis DATE: 00/05/31 17:34:20 GMT FROM: Giangiacomo Gandolfi at IAS/CNR Frascati A BeppoSAX follow up of GRB000528 with the Narrow Field Instruments started around May 28 at 20:50 UT, i.e. about 12 hours after the GRB. Preliminary analysis of the MECS (1.6-10 keV) data shows two previously unknown sources inside the field. The preliminary WFC error box (BeppoSAX Mail #10) contains both objects, while the refined one (BeppoSAX Mail #11 and GCN 677) only the second. Object #1: R.A.(2000)= 161.365 DEC(2000)= -33.975 Object #2: R.A.(2000)= 161.287 DEC(2000)= -33.986 both with an error radius of 1.5'. The source #1 is possibly fading, while the #2 seems to be consistent with a constant flux. Further and more detailed analysis are in progress. G. Gandolfi on behalf of BeppoSAX Mission Scientist //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 686 SUBJECT: GRB000528, Radio Observations DATE: 00/06/02 23:12:58 GMT FROM: Edo Berger at Caltech E. Berger (Caltech) and D. A. Frail (NRAO) report on behalf of a larger collaboration: "On June 1.11 UT we used the VLA at 8.46 GHz to observe the field centered on the refined position provided by the SAX WFC (GCN 677). There are no obvious radio candidates brighter than 0.14 mJy (3.5 sigma) inside the 1.5' region centered on object #2, which was identified by the SAX NFI (GCN 683). The 1.5' region centered on object #1 contains one bright source which is also present in the NRAO VLA Sky Survey (NVSS). Further observations are planned" This message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 691 SUBJECT: GRB000528, optical observations at ESO DATE: 00/06/07 16:46:29 GMT FROM: Nicola Masetti at ITeSRE,CNR,Bologna E. Palazzi, N. Masetti, E. Pian, F. Frontera (ITESRE, CNR, Bologna), A.J. Castro-Tirado (LAEFF, IAA), J. Hjorth (Univ. of Copenhagen), P.M. Vreeswijk, E.P.J. van den Heuvel (Univ. of Amsterdam), J. Greiner (AIP), P. Francois, J. Brewer and O. Hainaut (ESO) and L. Piro (IAS, CNR, Rome), on behalf of a larger collaboration, report: "We obtained optical R-band images of the field of GRB000528 (BeppoSAX Mails #00/10, #00/11) on 2000 May 29.10, May 29.96 and June 4.02 UT (i.e. 18 hr, 38 hr and 160 hr after the GRB, respectively) with the 1.54-meter Danish telescope (plus DFOSC) at ESO - La Silla (Chile). These images contain the BeppoSAX WFC error box of this GRB (GCNs #677, #681) and the two MECS sources reported in GCN #683. Seeing was ~1.3 arcsec on the three epochs. Exposure times were 15 min for the first observation, 10 min for the second and 45 min for the third. Photometric calibration was performed using standard stars in the Landolt field SA107 (Landolt 1992, AJ 104, 340). The comparison between pairs of images does not reveal any object with significant brightness variation down to a 3-sigma limiting magnitude of R ~ 23.3.". This message can be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN GRB OBSERVATION REPORT NUMBER: 700 SUBJECT: GRB000528: follow-up X-ray measurements and update of IPN annulus DATE: 00/06/13 18:52:48 GMT FROM: Jean int Zand at SRON GRB000528: follow-up X-ray measurements and update of IPN annulus E. Kuulkers, L. Kuiper, J.J.M. in 't Zand, J. Heise (Space Research Organization Netherlands), L.A. Antonelli (Osservatorio Astronomico di Roma), K. Hurley (University of California, Berkeley), L. Salotti (ASI, Rome), M. Stornelli, G. Celidonio (Telespazio, Rome), E. Costa, M. Feroci, G. Gandolfi (IAS-CNR, Rome), F. Frontera (ITESRE-CNR, Bologna, and University of Ferrara) L. Nicastro (IFCAI-CNR, Palermo), T. Cline (NASA Goddard Space Flight Center), E Mazets (Ioffe Physici-Technical Institute, St. Petersburg), C. Guidorzi, and E. Montanari (University of Ferrara) report: The BeppoSAX narrow-field instruments observed the region of GRB000528 twice: from May 28.71 to May 29.57 UT (TOO1, 8.3-28.9 hours after the burst) and from May 31.65 to June 1.49 (TOO2). The total exposure time obtained with the Medium-Energy Concentrator Spectrometers (MECS) is 58 ksec. Two X-ray sources close to one another were detected in the field, one at R.A. = 10h 45h 28m, Dec. = -33d 58' 14" (J2000.0), which we designate as 1SAX J1045.5-3358 (object 1 in GCN 683), and the other at R.A. = 10h 45m 08s, Dec. = -33d 59' 26", which we designate as 1SAX J1045.1-3359 (object 2 in GCN 683). Both sources have a conservative positional error of 1.5'. Object 2 is inside the WFC error region (GCN 677) while the centroid of object 1 is 2.5 arcmin outside that region. We note that a bright and archival radio source has been reported coincident with object 1 (GCN 686). A refined IPN analysis using Ulysses, BeppoSAX, and Konus data indicates that object 1 is far less consistent with the IPN annuli than object 2. The countrates for object 1 in MECS units 2 and 3 combined are (2.10+/-0.44)E-3 and (1.21+/-0.36)E-3 c/s for TOO1 and TOO2 respectively and for object 2 (2.40+/-0.46)E-3 and (0.65+/-0.32)E-3 c/s. Object 2 shows the strongest fading. Based on all pieces of information, we identify object 2 (1SAX J1045.1-3359) as the likely X-ray afterglow of GRB 000528. For maps of the error regions, see URL http://wfc.sron.nl/GRB000528/ Neither the WFC nor the GRBM observed the delayed emission 600 s after the burst (GCN 681); the source was unocculted at this time, and this emission would have been detected with high significance if it had originated from this source. We conclude that this emission was either solar in origin, or possibly from a different GRB. This message may be cited.