Gamma-ray Burst 050925

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN/BACODINE POSITION NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 25 Sep 05 09:04:46 UT
  NOTICE_TYPE:     Swift-BAT GRB Position
  TRIGGER_NUM:     156838,   Seg_Num: 0
  GRB_RA:          303.445d {+20h 13m 47s} (J2000),
                   303.500d {+20h 14m 00s} (current),
                   302.963d {+20h 11m 51s} (1950)
  GRB_DEC:         +34.334d {+34d 20' 04"} (J2000),
                   +34.352d {+34d 21' 08"} (current),
                   +34.182d {+34d 10' 55"} (1950)
  GRB_ERROR:       4.00 [arcmin radius, statistical only]
  GRB_INTEN:       767 [cnts]    Image_Peak=124 [image_cnts]
  TRIGGER_DUR:     0.064 [sec] 
  TRIGGER_INDEX:   10421     E_range: 25-100 keV
  BKG_INTEN:       32664 [cnts]
  BKG_TIME:        32664.00 SOD {09:04:24.00} UT
  BKG_DUR:         8 [sec]
  GRB_DATE:        13638 TJD;   268 DOY;   05/09/25
  GRB_TIME:        32673.53 SOD {09:04:33.53} UT
  GRB_PHI:         -15.74 [deg]
  GRB_THETA:        45.01 [deg]
  SOLN_STATUS:     0x3
  RATE_SIGNIF:     32.34 [sigma]
  IMAGE_SIGNIF:    12.32 [sigma]
  MERIT_PARAMS:     +1  +0  +0  -4  +2 +11  +0  +1 +43  +1 
  SUN_POSTN:       182.20d {+12h 08m 48s}   -0.95d {-00d 57' 13"}
  SUN_DIST:        115.99 [deg]
  MOON_POSTN:       94.11d {+06h 16m 26s}  +28.61d {+28d 36' 19"}
  MOON_DIST:       111.18 [deg]
  MOON_ILLUM:      49 [%]
  GAL_COORDS:       72.30, -0.07 [deg] galactic lon,lat of the burst (or transient)
  ECL_COORDS:      318.14, 52.33 [deg] ecliptic lon,lat of the burst (or transient)
  COMMENTS:        SWIFT-BAT GRB Coordinates.  
  COMMENTS:        This is a rate trigger.  
  COMMENTS:        A point_source was found.  
  COMMENTS:        This does not match any source in the on-board catalog.  
  COMMENTS:        This does not match any source in the ground catalog.  
  COMMENTS:        This is a GRB.  
  

• red DSS finding chart ps-file
  
  
• GCN/SWIFT NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 25 Sep 05 09:06:11 UT
  NOTICE_TYPE:     Swift-XRT Nack-Position
  TRIGGER_NUM:     156838,   Seg_Num: 0
  POINT_RA:        303.489d {+20h 13m 57s} (J2000)
  POINT_DEC:       +34.339d {+34d 20' 20"} (J2000)
  GRB_DATE:        13638 TJD;   268 DOY;   05/09/25
  GRB_TIME:        32765.32 SOD {09:06:05.32} UT
  COUNTS:          3    Min_needed= 20
  STD_DEV:         0.00   Max_StdDev_for_Good=28.44 [arcsec]
  PH2_ITER:        1    Max_iter_allowed= 4
  ERROR_CODE:      1
  COMMENTS:        SWIFT-XRT Nack Position.  
  COMMENTS:        No source found in the image.  
  

• GCN/SWIFT NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 25 Sep 05 09:08:12 UT
  NOTICE_TYPE:     Swift-BAT GRB Lightcurve
  TRIGGER_NUM:     156838,   Seg_Num: 0
  GRB_RA:          303.445d {+20h 13m 47s} (J2000),
                   303.500d {+20h 14m 00s} (current),
                   302.963d {+20h 11m 51s} (1950)
  GRB_DEC:         +34.334d {+34d 20' 04"} (J2000),
                   +34.352d {+34d 21' 08"} (current),
                   +34.182d {+34d 10' 55"} (1950)
  GRB_DATE:        13638 TJD;   268 DOY;   05/09/25
  GRB_TIME:        32673.62 SOD {09:04:33.62} UT
  TRIGGER_INDEX:   10421
  GRB_PHI:         -15.74 [deg]
  GRB_THETA:        45.01 [deg]
  DELTA_TIME:      22.00 [sec]
  TRIGGER_DUR:     0.064 [sec] 
  LC_URL:          sw00156838000msb.lc
  SUN_POSTN:       182.20d {+12h 08m 48s}   -0.95d {-00d 57' 13"}
  SUN_DIST:        115.99 [deg]
  MOON_POSTN:       94.11d {+06h 16m 26s}  +28.61d {+28d 36' 19"}
  MOON_DIST:       111.18 [deg]
  MOON_ILLUM:      49 [%]
  GAL_COORDS:       72.30, -0.07 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      318.14, 52.33 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-BAT GRB Lightcurve.  
  COMMENTS:           
  COMMENTS:        The next comments were copied from the BAT_POS Notice:  
  COMMENTS:        This is a rate trigger.  
  COMMENTS:        A point_source was found.  
  COMMENTS:        This does not match any source in the on-board catalog.  
  COMMENTS:        This does not match any source in the ground catalog.  
  COMMENTS:        This is a GRB.  
  

  
• GCN/SWIFT NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 25 Sep 05 09:08:31 UT
  NOTICE_TYPE:     Swift-UVOT Source List
  TRIGGER_NUM:     156838,   Seg_Num: 0
  POINT_RA:        303.489d {+20h 13m 57s} (J2000)
  POINT_DEC:       +34.339d {+34d 20' 19"} (J2000)
  POINT_ROLL:      288.086d
  GRB_DATE:        13638 TJD;   268 DOY;   05/09/25
  GRB_TIME:        32763.73 SOD {09:06:03.73} UT
  FILTER:          3, V
  BKG_MEAN:        0.000000
  N_STARS:         190
  X_OFFSET:        476 [pixels]
  Y_OFFSET:        555 [pixels]
  X_MAX:           1435 [pixels]
  Y_MAX:           1514 [pixels]
  DET_THRESH:      6
  PHOTO_THRESH:    3
  SL_URL:          sw00156838000msufc.fits
  SUN_POSTN:       182.20d {+12h 08m 49s}   -0.95d {-00d 57' 15"}
  SUN_DIST:        116.02 [deg]
  MOON_POSTN:       94.12d {+06h 16m 29s}  +28.61d {+28d 36' 19"}
  MOON_DIST:       111.17 [deg]
  MOON_ILLUM:      49 [%]
  GAL_COORDS:       72.33, -0.10 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      318.20, 52.32 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Source List.  
  

• GCN/SWIFT NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 25 Sep 05 09:09:46 UT
  NOTICE_TYPE:     Swift-UVOT Image
  TRIGGER_NUM:     156838,   Seg_Num: 0
  POINT_RA:        303.489d {+20h 13m 57s} (J2000)
  POINT_DEC:       +34.339d {+34d 20' 19"} (J2000)
  ROLL:            288.086d
  GRB_DATE:        13638 TJD;   268 DOY;   05/09/25
  GRB_TIME:        32763.73 SOD {09:06:03.73} UT
  FILTER:          3, V
  EXPOSURE_ID:     2278
  X_OFFSET:        795 [pixels]
  Y_OFFSET:        874 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       955
  Y_GRB_POS:       1034
  BINNING_INDEX:   1
  IM_URL:          sw00156838000msuni.fits
  SUN_POSTN:       182.20d {+12h 08m 49s}   -0.95d {-00d 57' 15"}
  SUN_DIST:        116.02 [deg]
  MOON_POSTN:       94.12d {+06h 16m 29s}  +28.61d {+28d 36' 19"}
  MOON_DIST:       111.17 [deg]
  MOON_ILLUM:      49 [%]
  GAL_COORDS:       72.33, -0.10 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      318.20, 52.32 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Image.  
  COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
  COMMENTS:        The image has 2x2 binning (compression).  
  

  
• GCN/SWIFT NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 25 Sep 05 09:09:52 UT
  NOTICE_TYPE:     Swift-UVOT Processed Source List
  TRIGGER_NUM:     156838,   Seg_Num: 0
  POINT_RA:        303.489d {+20h 13m 57s} (J2000)
  POINT_DEC:       +34.339d {+34d 20' 19"} (J2000)
  POINT_ROLL:      288.086d
  GRB_DATE:        13638 TJD;   268 DOY;   05/09/25
  GRB_TIME:        32763.73 SOD {09:06:03.73} UT
  FILTER:          3, V
  BKG_MEAN:        0.000000
  N_STARS:         190
  X_OFFSET:        476 [pixels]
  Y_OFFSET:        555 [pixels]
  X_MAX:           1435 [pixels]
  Y_MAX:           1514 [pixels]
  DET_THRESH:      6
  PHOTO_THRESH:    3
  SL_URL:          sw00156838000msufc.fits
  SUN_POSTN:       182.20d {+12h 08m 49s}   -0.95d {-00d 57' 15"}
  SUN_DIST:        116.02 [deg]
  MOON_POSTN:       94.12d {+06h 16m 29s}  +28.61d {+28d 36' 19"}
  MOON_DIST:       111.17 [deg]
  MOON_ILLUM:      49 [%]
  GAL_COORDS:       72.33, -0.10 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      318.20, 52.32 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Processed Source List.  
  

  
• GCN/SWIFT NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 25 Sep 05 09:10:24 UT
  NOTICE_TYPE:     Swift-UVOT Processed Image
  TRIGGER_NUM:     156838,   Seg_Num: 0
  POINT_RA:        303.489d {+20h 13m 57s} (J2000)
  POINT_DEC:       +34.339d {+34d 20' 19"} (J2000)
  ROLL:            288.086d
  GRB_DATE:        13638 TJD;   268 DOY;   05/09/25
  GRB_TIME:        32763.73 SOD {09:06:03.73} UT
  FILTER:          3, V
  EXPOSURE_ID:     2278
  X_OFFSET:        795 [pixels]
  Y_OFFSET:        874 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       955
  Y_GRB_POS:       1034
  BINNING_INDEX:   1
  IM_URL:          sw00156838000msuni.fits
  SUN_POSTN:       182.20d {+12h 08m 49s}   -0.95d {-00d 57' 15"}
  SUN_DIST:        116.02 [deg]
  MOON_POSTN:       94.12d {+06h 16m 29s}  +28.61d {+28d 36' 19"}
  MOON_DIST:       111.17 [deg]
  MOON_ILLUM:      49 [%]
  GAL_COORDS:       72.33, -0.10 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      318.20, 52.32 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Processed Image.  
  

  
• GCN/SWIFT NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 25 Sep 05 10:04:57 UT
  NOTICE_TYPE:     Swift-UVOT Source List
  TRIGGER_NUM:     156838,   Seg_Num: 0
  POINT_RA:        303.479d {+20h 13m 55s} (J2000)
  POINT_DEC:       +34.342d {+34d 20' 29"} (J2000)
  POINT_ROLL:      288.058d
  GRB_DATE:        13638 TJD;   268 DOY;   05/09/25
  GRB_TIME:        36042.45 SOD {10:00:42.45} UT
  FILTER:          3, V
  BKG_MEAN:        1.000000
  N_STARS:         190
  X_OFFSET:        476 [pixels]
  Y_OFFSET:        555 [pixels]
  X_MAX:           1435 [pixels]
  Y_MAX:           1514 [pixels]
  DET_THRESH:      9
  PHOTO_THRESH:    4
  SL_URL:          sw00156838000msufc.fits
  SUN_POSTN:       182.24d {+12h 08m 57s}   -0.97d {-00d 58' 08"}
  SUN_DIST:        116.00 [deg]
  MOON_POSTN:       94.65d {+06h 18m 35s}  +28.60d {+28d 35' 56"}
  MOON_DIST:       111.37 [deg]
  MOON_ILLUM:      49 [%]
  GAL_COORDS:       72.33, -0.09 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      318.18, 52.33 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Source List.  
  

• GCN/SWIFT NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 25 Sep 05 10:05:52 UT
  NOTICE_TYPE:     Swift-UVOT Processed Source List
  TRIGGER_NUM:     156838,   Seg_Num: 0
  POINT_RA:        303.479d {+20h 13m 55s} (J2000)
  POINT_DEC:       +34.342d {+34d 20' 29"} (J2000)
  POINT_ROLL:      288.058d
  GRB_DATE:        13638 TJD;   268 DOY;   05/09/25
  GRB_TIME:        36042.45 SOD {10:00:42.45} UT
  FILTER:          3, V
  BKG_MEAN:        1.000000
  N_STARS:         190
  X_OFFSET:        476 [pixels]
  Y_OFFSET:        555 [pixels]
  X_MAX:           1435 [pixels]
  Y_MAX:           1514 [pixels]
  DET_THRESH:      9
  PHOTO_THRESH:    4
  SL_URL:          sw00156838000msufc.fits
  SUN_POSTN:       182.24d {+12h 08m 57s}   -0.97d {-00d 58' 08"}
  SUN_DIST:        116.00 [deg]
  MOON_POSTN:       94.65d {+06h 18m 35s}  +28.60d {+28d 35' 56"}
  MOON_DIST:       111.37 [deg]
  MOON_ILLUM:      49 [%]
  GAL_COORDS:       72.33, -0.09 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      318.18, 52.33 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Processed Source List.  
  

  
• GCN notice #4034
  S.T. Holland (GSFC/USRA), S. Barthelmy (GSFC), A. Beardmore (U. Leicester), N. Gehrels (GSFC), J. Kennea (PSU), K. Page (U. Leicester), D. Palmer (LANL), S. Rosen (MSSL) on behalf of the Swift team:
  At 09:04:33 UT, Swift-BAT triggered and located GRB050925 (trigger=156838). The BAT on-board calculated location is RA,Dec 303.445d,+34.334d {20h 13m 47s,+34d 20' 04"} (J2000), with an uncertainty of 3 arcmin (radius, 90% containment, stat+sys). We note that the galactic latitude is -0.1. The BAT light curve shows a single-peak structure with a total duration of less than 128 msec. The peak count rate was ~8000 counts/sec (15-350 keV), for the 128-msec binning at 0.00 seconds after the trigger.
  The spacecraft slewed immediately and the XRT began observing the GRB at 09:06:05 UT, 92 sec after the BAT trigger. The on-board detection algorithm failed to centroid on a source, so no prompt X-ray position is available. The XRT prompt spectra and lightcurve show no signficant X-ray emission in the field, suggesting that any X-ray counterpart to this burst is faint.
  The UVOT began observing this field 91 sec after the BAT trigger. The small UVOT TDRSS image covers 25% of the BAT error circle. However, the full-field UVOT source list contains only catalogued sources, and in particular no uncatalogued source is found inside the BAT error circle. At the present time it is not possible to determine a limiting magnitude for this field. The V-band extinction in this direction is A_V = 7.05 mag.
  We note that this burst has soft emission in BAT which may not be consistent with it being in the short-hard class of GRB. At low galactic latitude it is possible that it is a new SGR. At this point we can not be sure of its classification.
• GCN/SWIFT NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 25 Sep 05 10:06:07 UT
  NOTICE_TYPE:     Swift-UVOT Image
  TRIGGER_NUM:     156838,   Seg_Num: 0
  POINT_RA:        303.479d {+20h 13m 55s} (J2000)
  POINT_DEC:       +34.342d {+34d 20' 29"} (J2000)
  ROLL:            288.058d
  GRB_DATE:        13638 TJD;   268 DOY;   05/09/25
  GRB_TIME:        36042.45 SOD {10:00:42.45} UT
  FILTER:          3, V
  EXPOSURE_ID:     2278
  X_OFFSET:        795 [pixels]
  Y_OFFSET:        874 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       955
  Y_GRB_POS:       1034
  BINNING_INDEX:   1
  IM_URL:          sw00156838000msuni.fits
  SUN_POSTN:       182.24d {+12h 08m 57s}   -0.97d {-00d 58' 08"}
  SUN_DIST:        116.00 [deg]
  MOON_POSTN:       94.65d {+06h 18m 35s}  +28.60d {+28d 35' 56"}
  MOON_DIST:       111.37 [deg]
  MOON_ILLUM:      49 [%]
  GAL_COORDS:       72.33, -0.09 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      318.18, 52.33 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Image.  
  COMMENTS:        The GRB Position came from the Window Position in the Mode Command.  
  COMMENTS:        The image has 2x2 binning (compression).  
  

  
• GCN/SWIFT NOTICE
  

  TITLE:           GCN/SWIFT NOTICE
  NOTICE_DATE:     Sun 25 Sep 05 10:06:24 UT
  NOTICE_TYPE:     Swift-UVOT Processed Image
  TRIGGER_NUM:     156838,   Seg_Num: 0
  POINT_RA:        303.479d {+20h 13m 55s} (J2000)
  POINT_DEC:       +34.342d {+34d 20' 29"} (J2000)
  ROLL:            288.058d
  GRB_DATE:        13638 TJD;   268 DOY;   05/09/25
  GRB_TIME:        36042.45 SOD {10:00:42.45} UT
  FILTER:          3, V
  EXPOSURE_ID:     2278
  X_OFFSET:        795 [pixels]
  Y_OFFSET:        874 [pixels]
  WIDTH:           160 [pixels]
  HEIGHT:          160 [pixels]
  X_GRB_POS:       955
  Y_GRB_POS:       1034
  BINNING_INDEX:   1
  IM_URL:          sw00156838000msuni.fits
  SUN_POSTN:       182.24d {+12h 08m 57s}   -0.97d {-00d 58' 08"}
  SUN_DIST:        116.00 [deg]
  MOON_POSTN:       94.65d {+06h 18m 35s}  +28.60d {+28d 35' 56"}
  MOON_DIST:       111.37 [deg]
  MOON_ILLUM:      49 [%]
  GAL_COORDS:       72.33, -0.09 [deg] galactic lon,lat of the pointing direction
  ECL_COORDS:      318.18, 52.33 [deg] ecliptic lon,lat of the pointing direction
  COMMENTS:        SWIFT-UVOT Processed Image.  
  

  
• GCN notice #4035
  C. Guidorzi, C.G. Mundell, A. Gomboc, I. A. Steele, C.J. Mottram, A. Monfardini, R.J. Smith, D. Carter, M.F. Bode (Liverpool JMU), E. Rol, P. O'Brien, N. Bannister (Leicester) report:
  "The 2-m Faulkes North Telescope robotically followed up Swift burst GRB050925 3.3 min after the GRB trigger time. The automatic "detection mode" procedure did not detect any obvious candidate brighter than about R=19 mag from 3x10-s images (mean epoch of 3.7 min after the GRB), with FOV of 4.6'x4.6' centred on the BAT in-flight location. The field is crowded and the extinction in V is about 6.3 mag (Schlegel et al. maps). Visual inspection of the images confirms the reported non-detection.
  The limiting magnitude is automatically calculated with respect to the USNOB1.0 'R2' values of the field objects."
• GCN notice #4036
  Y. Qiu, C.L. Lu (BAO), Y.Q. Lou (THCA), Y. Urata (RIKEN), K.Y. Huang (NCU) on behalf of EAFON report
  " We have imaged the entire error region of GRB 050925 (Holland et al. GCN 4034) using 0.8-m telescope at XingLong Observatory, China. The I-band observations were performed form 11.27 UT to 11.78 UT (~ 2.19 to 2.70 hours after the burst). Compare with DSS-II images, no new source was found in our co-add image (300s x 6). The limiting magnitude is I~ 20.6, in comparison with USNO-B1.0 stars(S/N=3). The extinction in I is about 4.1 mag (Schlegel et al. 1998).
  This message may be cited."
• GCN notice #4037
  C. Markwardt (GSFC/UMD), L. Barbier (GSFC), S. Barthelmy (GSFC), J. Cummings (GSFC/NRC), E. Fenimore (LANL), N. Gehrels (GSFC), D. Hullinger (GSFC/UMD), K. Hurley (UC Berkeley), H. Krimm (GSFC/USRA), J. Norris (GSFC), D. Palmer (LANL), A. Parsons (GSFC), T. Sakamoto (GSFC/NRC), G. Sato (ISAS), J. Tueller (GSFC) on behalf of the Swift-BAT team:
  Using the full data set from the recent telemetry downlink, we report further analysis of Swift-BAT Trigger #156838 (Holland, et al., GCN 4034). The ground-analysis position is RA,Dec 303.476,+34.332 {20h 13m 54.2s,34d 19' 54.0"} (J2000) with an uncertainty of 1.5 arcmin (radius, 90%, stat+sys). T90 is 0.068 +- 0.027 sec. The lightcurve is a single spike. Other than the initial spike at the trigger time, there is no detectable emission from T-300 to T+454 sec. Fitting our standard simple power law over the full interval from T-0.039 to T+0.614 sec, the photon index is 1.74 +/- 0.17 with a fluence of 7.5 +/- 0.9 X 10^-8 erg/cm^2. The flux in a 1-sec wide window starting at T-0.39 sec is 1.5 +/- 0.3 ph/cm^2/sec. We also fit a blackbody spectrum yielding a slightly improved reduced Chi2 with kT = 15.4 +/- 1.5 keV. We note that this kT is consistant with small-flare events from SGRs and that the RA,Dec is not any of the known SGRs. All values are in the 15-150 keV band at the 90% confidence level.
• GCN notice #4038
  S. Rosen (MSSL), S. T. Holland (GSFC/USRA), F. Marshall(GSFC), P. Boyd (GSFC-UMBC), N. Gehrels (GSFC) on behalf of the Swift/UVOT team.
  The Swift/UVOT began observing the field of the short-soft burst, GRB050925, at 09:06:03 UT, 90s seconds after the BAT trigger (Holland et al., GCN 4034). There has been no reported XRT detection of a fading afterglow and no counterpart found in ground-based observations (GCN 4035 and 4036) so no positional information other than the BAT location (revised position from Markwardt et al., GCN 4037) is currently available.
  Within the 1.5 arcmin BAT error circle (GCN 4037), no new optical/UV source is detected and we derive the following 3 sigma upper limit magnitudes on any optical/UV counterpart in the summed images in each UVOT filter (from 6" radius apertures centred on the BAT location which is representative of the local background).

      Filter  T_range(sec)  Exp(sec)  3sig UL
  
        V        90-50567     3885     20.2
        B      3787-57196     4600     21.8
        U      3682-56297     4654     21.2
        UVW1   3578-52239     4080     21.4
        UVM2   3473-51474     4541     21.8
        UVW2   3892-62080     4356     21.8
  

  Where T_range is the time post-trigger over which the summed images were accumulated and Exp is the total exposure time. The magnitudes upper limits are not corrected for extinction which is high since the BAT position is in the galactic plane.
• GCN notice #4039
  A.J. van der Horst (University of Amsterdam) reports on behalf of a larger collaboration:
  "We observed the position of the short burst GRB 050925 at 4.9 GHz with the Westerbork Synthesis Radio Telescope at Sep 25 13.48 UT to Sep 26 1.47 UT, i.e. 0.18 - 0.68 days after the burst (GCN 4034). No radio sources are seen in the refined Swift-BAT error circle (GCN 4037) above a 3-sigma level of 72 microJy. We measure a formal flux of 44 +/- 24 microJy at the center of the error circle (GCN 4037). We note there is a bright radio source, with a flux of 878 +/- 31 microJy, just outside this error circle at RA 20h13m47.8s, Dec +34d18'38" (J2000)."
  This message may be cited.
• GCN notice #4042
  J. S. Bloom (UC Berkeley) reports:
  "We observed the field of GRB 050925 (=Swift #156838), a possible new SGR (Holland et al. GCN #4034), with the PAIRITEL 1.3m starting on 2005-09-26 02:44:26 UTC. We find no significantly detected source within 1 arcsec of the bright radio source reported by van der Horst (GCN #4039). The approximate 5 sigma upper limits in the 1490 sec integration is Ks > 18.3 mag, H > 18.5, and J > 19.3 mag. Further observations are planned."
  A finding chart showing the 2MASS and PAIRITEL images may be found at: http://astro.berkeley.edu/~jbloom/sgr2013+34.gif
  This message may be cited.
  
• GCN notice #4043
  A.P. Beardmore (U. Leicester), K.L. Page (U. Leicester), N. Gehrels (GSFC), J. Greiner (MPE), J. Kennea (PSU), J. Nousek (PSU), J.P. Osborne (U. Leicester) and G. Tagliaferri (INAF-OAB) report on behalf of the Swift/XRT team:
  We have analysed 27.8 ks of XRT data for the BAT soft short burst (trigger 156838; GCN 4034, Holland et al.), starting 99.5 s after the BAT trigger. No fading X-ray source is found within the refined BAT error circle (GCN 4037, Markwardt et al.). However, there exists a source with a constant count rate of 0.0015+/-0.0004 counts s^-1 at RA(2000) = 20 13 48.0, Dec(J2000) = +34 19 53.7 (6.4 arcsec radius uncertainty at 90% containment) within the BAT error circle, coincident with a B=13.0, R=11.6 magnitude USNO object (GSC0267902398 in the Guide Star Catalogue).
  The spectrum of this source is best modelled by either a blackbody (with a temperature of 0.19 +0.10/-0.05 keV, column density < 0.3E22 cm^-2 and an unabsorbed 0.2-10.0 keV flux of 7.0E-14 ergs cm^-2 s^-1) or a thermal plasma Mekal model (with a temperature of 0.87 +0.41/-0.44 keV, column density < 0.2E22 cm^-2, an abundance consistent with solar and an unabsorbed 0.2-10.0 keV flux of 4.6E-14 ergs cm^-2 s^-1). We note the observed column density upper limit to this source is significantly less than the Galactic value of 1.1E22 cm^-22 (Dickey & Lockman, 1990), suggesting it is nearby and unlikely to be a GRB.
  Except for the XRT source coincident with the USNO object, there are no sources detected within the BAT error circle. The 3 sigma upper limit on the count-rate is 0.0006 counts s^-1, corresponding to an unabsorbed 0.2-10 keV flux of 3.0E-14 ergs cm^-2 s^-1 assuming a Crab-like spectrum.
• GCN notice #4057
  A.J. van der Horst (University of Amsterdam) reports on behalf of a larger collaboration:
  "We reobserved the position of the short burst GRB 050925 at 4.9 GHz with the Westerbork Synthesis Radio Telescope at Oct 1 14.66 UT to Oct 2 1.08 UT, i.e. 6.23 - 6.67 days after the burst (GCN 4034). No radio sources are seen in the refined Swift-BAT error circle (GCN 4037) above a 3-sigma level of 66 microJy. We measure a formal flux of 10 +/- 22 microJy at the center of the error circle (GCN 4037). The bright radio source we reported in GCN 4039, just outside this error circle, has a flux of 881 +/- 32 microJy; so this source did not vary significantly between ~0.43 and ~6.45 days."
  This message may be cited.
• GCN Circular #4264
  Nanda Rea (SRON), Elisa Costantini (SRON) and Gianluca Israel (INAF-OAR)
  report:
  We report on the preliminary analysis of a 27ks XMM-Newton ToO observation of GRB 050925 (GCN 4034 Holland et al.; GCN 4037 Markwardt et al.) performed on 2005 October 12. The very short (128 ms) duration of this GRB and the lack of any bright UV/Opt/IR afterglow (GCN 4038 Rosen et al.; GCN 4035 Guidorzi et al.; GCN 4036 Qiu et al.; GCN 4042 Bloom et al.) suggested a probable Soft Gamma-Ray Repeater (SGR) nature of this burst. A bright, seemingly not variable, radio source was reported at 4.9 GHz, just outside the refined Swift-BAT error circle (GCN 4039 and GCN 4057 van der Horst et al.).
  In the Swift-BAT 1.5 arcminutes error circle of GRB 050925 (GCN 4037 Markwardt et al.) the XMM-PN detects only one source at RA: 20 13 47.84, Dec: 34 19 52.0 (1.2 arcsec associated error circle; errors given at 90%). The Epic-PN source count rate is 0.022+/-0.001 counts/s. This source is consistent with the one detected by the Swift-XRT (GCN 4043 Beardmore et al.). The USNO object, previously consistent with the XRT position, lies now outside the refined XMM error circle.
  A preliminary timing analysis does not show any significant periodic signal. The source spectrum is soft and not well fitted by simple models as absorbed power-law, blackbody or bremsstrahlung (chi^2/dof=4.0, 2.8 and 3.1, respectively). The fit improves using two components, power-law plus blackbody or two blackbodies (chi^2/dof=0.9). The correspondent absorbed flux (4x10^-14 ergs*cm^-2*s^-1 in the 0.5-10 keV band) is consistent with the XRT value. A detailed spectral analysis is on-going. As already noted in GCN 4043 by Page et al., the absorption value of this source (~10^21 cm^-2) is very low compared with the Galactic absorption in that direction (~10^22 cm^-2), suggesting a probable nearby object. Note that there is not any X-ray source (flux upper limit of ~10^-15 ergs*cm^-2*s^-1) coincident with the position of the bright radio source reported in GCN 4039 and GCN 4057 (van der Horst et al.).
  At this stage, this source cannot be unambiguously identified neither as a Soft Gamma-Ray Repeater in quiescence, nor as the responsible for the GRB 050925.
  We thank the XMM-Newton team for having performed this observation.
• GCN Circular #4274
  A.De Luca, P.Caraveo, P.Esposito, S.Mereghetti, A.Tiengo (INAF/IASF Mi), report:
  we have analyzed the data from the XMM-Newton observation of the soft short burst GRB050925, observed by Swift to have characteristics similar to that of Soft Gamma Repeaters (SGRs) (Holland et al., GCN4034). An independent analysis of the XMM data was reported by Rea et al.(GCN4264).
  We give here the detailed results of a source detection on the EPIC dataset. Such results will become an important reference in case the putative SGR will enter a phase of enhanced activity.
  We used independently the pn camera data and the combined MOS1+MOS2 data. We selected the energy ranges 0.3-2 keV, 2-8 keV and 0.3-8 keV. The MOS and pn positions are found to be consistent within ~1.5 arcsec, in agreement with the known astrometric accuracy of the EPIC cameras. Thus, we assume 1.5 arcsec as the 1sigma uncertainty on the X-ray sources' positions. In the source list below we quote the J2000 coordinates as derived from the pn camera (unless otherwise specified).
  Since the field of GRB050925 is very crowded we focus on the region closer to the 1.5 arcmin BAT error circle (Markwardt et al., GCN4037). 6 X-ray sources (named XMM1...XMM6) are detected within 2 arcmin of the BAT coordinates.
  Finding charts from pn and MOS data may be found at http://www.iasf-milano.inaf.it/~deluca/grb050925 Please note that the circles around XMM sources are meant to help locate them. In the scale used for the figures the XMM error boxes are smaller than 1 pixel.
  Sources inside the BAT circle:

  XMM1 - RA 20:13:47.81, Dec +34:19:51.9 - it is the brightest
         source located within the BAT error circle. It is the
         steady source discovered in Swift/XRT data by Beardmore
         et al. (GCN4043) and interpreted as a field star.
         Its coordinates, within errors, are consistent with a bright
         optical source (B~12.4, R~11.9, source id.1243-0400741 in
         USNO-B1). Its spectrum is well described by a mekal plasma
         model with NH<5x10^20 cm^-2, kT~0.6 keV, abundance ~0.3 solar
         values and observed flux of 2.7x10^-14 erg cm^-2 s^-1
         in 0.3-8 keV. The resulting Fx/Fopt is of ~3x10^-4.
         Thus, in agreement with Beardmore et al.(GCN4043), we
         conclude that source XMM1 is most likely a nearby star.
         Rea et al.(GCN4264), assuming a smaller X-ray error circle,
         questioned the association with the bright optical source
  
  XMM2 - RA 20:13:57.85, Dec +34:19:56.5 - detected with S/N~3,
         in the 0.3-2 keV range only.
         Assuming a Crab spectrum with Galactic absorption
         (1.1x10^22 cm^-2 according to Dickey & Lockman, 1990), its
         observed flux is (2-3)x10^-15 erg cm^-2 s^-1 (0.3-2 keV).
         No obvious optical counterparts are found in the DSS plates.
  

  Sources outside the BAT circle:

  XMM3 - RA 20:13:54.97, Dec +34:18:22.4 - located at 1.55 arcmin
         from the BAT position, it is detected with S/N~3
         in MOS data only (in the pn detector it lies on a bad column),
         with a flux  similar to source XMM2.
         An optical source with R~17 is found within 3 arcsec.
  
  XMM4 - RA 20:13:56.06, Dec +34:21:28.9 - located at 1.61 arcmin
         from the BAT position, it is detected with S/N~3
         in MOS data only (in the pn detector  it lies on a bad column),
         with a flux similar to source XMM2.
         An optical source with R~16.5 is found within 2.2 arcsec.
  
  XMM5 - RA 20:14:01.59, Dec +34:21:03.1 - located at 1.89 arcmin
         from the BAT position, it lies within 1.5 arcsec of a
         bright optical source (B~13.1, R~11.4, source id.1243-0401091
         in USNO-B1 catalog), its spectrum is consistent with a mekal
         plasma model with absorption smaller than the Galactic value,
         kT~0.67 keV and abundance ~0.4 solar values; the observed flux
         is ~1x10^-14 erg cm^-2 s^-1 (0.2-5 keV). Fx/Fopt is ~10^-4.
         It is most likely  a star.
  
  XMM6 - RA 20:13:45.17, Dec +34:20:23.8 - located at 1.93 arcmin
         from the BAT position, its spectrum is consistent
         with a power law (photon index ~1.8) absorbed by the Galactic
         column. Its observed flux is ~2x10^-14 erg cm^-2 s^-1
         (0.2-8 keV). No obvious optical counterparts.
  

  No other sources within 2 arcmin of the BAT position are seen. Using the present XMM observation we can estimate the upper limit flux as follows: assuming a Crab-like spectrum with Galactic absorption, a S/N=3 detection corresponds to a flux of ~3x10^-15 erg cm^-2 s^-1 in the 0.3-2 keV band and ~8x10^-15 erg cm^-2 s^-1 in the 0.3-8 keV band.
  We thank the XMM Project Scientist, N.Schartel, for approval of this TOO, and the XMM people at Vilspa for performing it.
• 1008.0226 from 3 Aug 10
  T. Sakamoto et al.: Probing the Nature of Short Swift Bursts via Deep INTEGRAL Monitoring of GRB 050925
  M. Parsons, G. Sato, M. Stamatikos, J. Tueller We present results from Swift, XMM-Newton, and deep INTEGRAL monitoring in the region of GRB 050925. This short Swift burst is a candidate for a newly discovered soft gamma-ray repeater (SGR) with the following observational burst properties: 1) galactic plane (b=-0.1 deg) localization, 2) 150 msec duration, and 3) a blackbody rather than a simple power-law spectral shape (with a significance level of 97%). We found two possible X-ray counterparts of GRB 050925 by comparing the X-ray images from Swift XRT and XMM-Newton. Both X-ray sources show the transient behavior with a power-law decay index shallower than -1. We found no hard X-ray emission nor any additional burst from the location of GRB 050925 in ~5 Ms of INTEGRAL data. We discuss about the three BATSE short bursts which might be associated with GRB 050925, based on their location and the duration. Assuming GRB 050925 is associated with the H II regions (W 58) at the galactic longitude of l=70 deg, we also discuss the source frame properties of GRB 050925.