Gamma-ray Burst 001025

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN notice #861
  D. A. Smith (UMich), A. M. Levine, and R. Remillard (MIT), on behalf of the RXTE/ASM teams at MIT and NASA/GSFC, and and K. Hurley (UCB) and T. Cline (NASA/GSFC) on behalf of the NEAR GRB team, report:
  The RXTE All-Sky Monitor has detected a gamma-ray burst, beginning at about 03:10:05 UTC on 25 Oct 2000. As recorded by the ASM, the light curve consists of a single peak, lasting approximately 15-20 seconds. The event was hard, as measured in the ASM, reaching a peak 5-12 keV flux of ~4 Crab, and a 1.5-3 keV flux of ~1.5 Crab. It was detected in a single camera, yielding an error box with a length of 1.6 degrees and a width of 4.0 arcminutes. The center of the error box is at R.A. = 8h38m, Decl. = -13o16'.0 (J2000.0). The corners of the box are at the locations:
  

  130.2309d {08h40m55s} -13.6681d {-13o40'05"}
  130.2542d {08h41m01s} -13.6247d {-13o37'29"}
  128.7598d {08h35m02s} -12.8590d {-12o51'32"}
  128.7357d {08h34m57s} -12.9034d {-12o54'12"}
  

  NEAR also observed this burst. As observed by NEAR, in the energy range >~100 keV, and with 1 s resolution, the burst consisted of a single one second long spike followed by weak emission for ~5 seconds. A very coarse comparison of the NEAR and RXTE times gives an annulus which contains, but does not improve upon the ASM error box. Data from the Konus-Wind and/or Ulysses experiments will be available around 0600 UT on the 26th, and should result in a small RXTE/IPN error box.
  See the web page at http://xte.mit.edu/grb001025/ for figures and further developments.
  

  The dark blue lines in the above figure represent an annulus derived from a very coarse comparison of the arrival times at NEAR and RXTE.The green lines show the improved annulus from triangulation from Ulysses and NEAR.

  

  The joint error box superimposed over the DSS.

• GCN notice #863
  K. Hurley and T. Cline, on behalf of the Ulysses and NEAR GRB teams, and D. Smith, on behalf of the RXTE ASM GRB team, report:
  Ulysses and NEAR observed this burst (GCN #861). As observed by Ulysses, it had a duration ~5 s, a 25-100 keV fluence of ~3.2E-06 erg/cm^2, and a peak flux over 0.5 s of 2.0E-06 erg/cm^2 s. Using the RXTE ASM error box and the IPN annulus, we derive an ~25 sq. armin. error box (3 sigma) whose coordinates are:

       RA(2000)         DEC(2000)
  08 h 36 m 36.5 s  -13 o 04 ' 30 "  (CENTER)
  08 h 36 m 41.9 s  -13 o 07 ' 00 "  (CORNER)
  08 h 36 m 54.3 s  -13 o 05 ' 00 "  (CORNER)
  08 h 36 m 30.5 s  -13 o 02 ' 00 "  (CORNER)
  08 h 36 m 19.5 s  -13 o 04 ' 00 "  (CORNER)
  

  This error box may be improved.
• GCN notice #864
  K. Hurley reports:
  There was an error of about 1' in the coordinates cited in GCN 863. The coordinates of the IPN/RXTE error box should have been

          RA(2000)        DEC(2000)
  
  08 h 36 m 34.7 s        -13 o 05 ' 03 "  (CENTER)
  08 h 36 m 40.8 s        -13 o 07 ' 30 "  (CORNER)
  08 h 36 m 53.3 s        -13 o 05 ' 46 "  (CORNER)
  08 h 36 m 28.8 s        -13 o 02 ' 35 "  (CORNER)
  08 h 36 m 16.1 s        -13 o 04 ' 20 "  (CORNER)
  

  I regret any confusion this may have caused, but I do have a good excuse (jet lag).
• GCN notice #866
  M. Uemura, T. Kato, R. Ishioka, H. Iwamatsu (Kyoto Univ.) and H. Yamaoka (Kyushu Univ.) report on behalf of VSNET-grb collaboration:
  We have observed the error box of GRB 001025A (Hurley et al., GCN #863, #864) with 8 x 300s R band exposures with the 60-cm RC telescope at Ouda station starting Oct. 26.79 UT. Due to the bad weather, the limiting magnitude was mag about 18.0. Comparing with Digital Sky Survey 2nd generation R image, no new object has not detected within the error box. Further observation is planned to be carried out tonight.
• GCN notice #867
  J. P. U. Fynbo, P. Moller (ESO, Garching), B. Milvang-Jensen (U. of Nottigham), I. Burud (U. of Liege), M. I. Andersen (U. of Oulu), H. Pedersen, B. L. Jensen, J. Hjorth (U. of Copenhagen), and J. Gorosabel (DSRI, Copenhagen), on behalf of a larger collaboration report:
  We have obtained images covering the error box of GRB 001025 (Smith et al., GCN #861; Hurley et al., GCNs #863, 864) with the 1.54-m Danish Telescope (+DFOSC) on La Silla, the 8.2-m Antu (VLT UT1) (+FORS1) on Paranal, and the 2.56-m Nordic Optical Telescope (NOT) (+ALFOSC) on La Palma, as follows:

  Start (UT)   Tel.  Filter  Exp.time  Seeing Lim.Mag
  ===================================================
  Oct. 26.29   Dk-1.5m R     3x300s    1.4"   ~22.5
  Oct. 26.34   Antu    R     10x200s   0.8"   ~24.5
  
  Oct. 27.20   NOT     R     13x600s   1.7"   ~23.2
  Oct. 27.32   Antu    R     8x200s    0.8"   ~24.5
  

  The limits are preliminary and based on USNO-A2.0 photometry. Comparison of the images yields no significantly variable objects down to R=24.5.
  A section of the Antu Oct. 26.34 image is available at: http://www.astro.ku.dk/~brian_j/grb/grb001025/ .
  and reproduced below:
  

• GCN notice #869
  B. Altieri, N. Schartel, M. Santos, L. Tomas, M. Guainazzi (XMM-Newton SOC, ESA), L. Piro (IAS/CNR), A. Parmar (SSD/ESA) report:
  XMM-Newton observed the location of GRB001025 (Hurley et al. GCN 864) from Oct.27.003 to Oct.27.46 UT, i.e. 1.9 days after the burst. Preliminary analysis of the EPIC-pn and EPIC-MOS images show the presence of at least 4 sources in the error box. The brighter source (S1) has a flux of about 1-2 10**-13 erg/cm2/s in the 0.5-10 keV range. We cannot exclude a decay by about 40% over the whole observation, that would be expected from a decay power law with a slope of -1.5, the average value observed in X-ray afterglows. The remaining sources (S2, S3 & S4) are too faint to constrain the variability.
  The following coordinates have been derived with a preliminary attitude reconstruction (equinox 2000):

  S1  R.A.= 8h36m38.7s  Decl.= -13 06' 00"
  S2  R.A.= 8h36m30.1s  Decl.= -13 05' 31"
  S3  R.A.= 8h36m30.5s  Decl.= -13 03' 48"
  S4  R.A.= 8h36m48.6s  Decl.= -13 05' 47"
  

  At this stage of reduction the error is expected to be less than 20". Refined coordinates will be distributed as soon as the final attitude reconstruction is obtained.
• GCN notice #884
  B. Altieri, N. Schartel, D. Lumb (XMM-Newton), L. Piro (IAS/CNR), A. Parmar (SSD/ESA) report:
  analysis of the XMM-Newton observation of GRB001025 (Altieri et al. GCN 869) based on the final attitude reconstruction shows the presence of 2 sources in the IPN/RXTE error box (Hurley et al. GCN864):

  S1 (J2000): R.A. =  8h36m35.92s   Decl. =  -13 04' 09.9"
  S2 (J2000): R.A. =  8h36m27.24s   Decl. =  -13 03' 41.5"
  

  The error is expected to be less than 10".
  Seven objects in the field of view of the X-ray cameras (30 arcminute diameter) appear to be the counterpart of sources in the USNO-A2.0 catalogue. They show position coincidences better than 7 arcsec for the positions obtained from the EPIC-MOS images and better than 4 arcsec for the positions obtained from the EPIC-pn image, respectively.