Gamma-ray Burst 991105

On November 5, 1999, 16:40:44 UT a GRB (BATSE trigger 7841) was detected by the BeppoSAX GRBM and WFC instruments and localized to 5 arcmin accuracy. A BeppoSAX follow-up observation with the NFI instruments was not performed due to sun-angle constraints.

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• IAUC 7301 WFC discovery
• IAUC 7303 correction of WFC position

• BACODINE FINAL BURST POSITION NOTICE
  

  NOTICE_DATE:   Fri 05 Nov 99 16:42:25 UT
  NOTICE_TYPE:   Final
  TRIGGER_NUM:   7841
  GRB_RA:        184.04d {+12h 16m 10s} (J2000),
                 184.04d {+12h 16m 10s} (current),
                 183.37d {+12h 13m 28s} (1950)
  GRB_DEC:       -62.49d {-62d 29' 26"} (J2000),
                 -62.49d {-62d 29' 23"} (current),
                 -62.21d {-62d 12' 46"} (1950)
  GRB_ERROR:     2.9 [deg radius, statistical only]
  GRB_FLUENCE:   12253 [cnts]    Peak=3645 [cnts/sec]  Del_t=6.4 [sec]
  GRB_TIME:      60044.79 SOD {16:40:44.79} UT
  GRB_DATE:      11487 TJD;   309 DOY;   99/11/05
  

• BACODINE/HUNTSVILLE/LOCBURST BURST POSITION NOTICE
  

  NOTICE_DATE:   Fri 05 Nov 99 17:09:13 UT
  NOTICE_TYPE:   Hunts_Locburst
  TRIGGER_NUM:   7841
  GRB_RA:        160.65d {+10h 42m 36s} (J2000),
                 160.65d {+10h 42m 36s} (current),
                 160.17d {+10h 40m 42s} (1950)
  GRB_DEC:       -60.22d {-60d 13' 14"} (J2000),
                 -60.22d {-60d 13' 11"} (current),
                 -59.96d {-59d 57' 30"} (1950)
  GRB_ERROR:     2.0 [deg radius, statistical only]
  GRB_INTEN:     3390 [cnts]    Peak=3390 [cnts/sec]
  GRB_TIME:      60044.79 SOD {16:40:44.79} UT
  GRB_DATE:      11487 TJD;   309 DOY;   99/11/05
  

• BeppoSAX GRB alert n. 99/29 and GCN notice #430
  On Nov.5, 16:40:44 UT a GRB (GRB991105) was detected simultaneously by the GRBM and WFC of BeppoSAX (also BATSE trigger #7841).
  Preliminary coordinates from WFC are:

  R.A.(2000)=180.80
  DEC(2000)= -66.76
  

  with an error radius of about 5'.
• BeppoSAX GRB alert n. 99/30 and GCN notice #431
  Refined coordinates from WFC are:

    R.A.(2000)= 180.753
    DEC(2000)= -66.814
  

  with an error radius of about 3.6'
• GCN notice #432
  M.J.S. Smith, J.in't Zand, Space Research Organization of the Netherlands (SRON), Utrecht, G. Tarei, M. Dadina, BeppoSAX Scientific Operation Center (SOC), Rome, and L. Piro, Istituto di Astrofisica Spaziale/CNR, Rome report:
  The BeppoSAX Gamma Ray Burst Monitor (GRBM) and Wide Field Camera (WFC unit 2) observed a gamma-ray burst triggered on November 5.6950 UT (BATSE trigger 7701). A preliminary analysis reveals a duration of 13 s in the GRBM, with a peak intensity of 970 cts/s in the 40-700 keV energy band. In the WFC, the duration is 40 s and the peak flux is 1.1 Crab (2-28 keV). The position of the X-ray counterpart is R.A. = 12h 03m 01s, Decl. = -66d 48' 49" (equinox 2000.0) with an 99% error radius of 3.6'. A BeppoSAX NFI follow-up observation will not be performed due to sun-angle constraints.
• BeppoSAX GRB alert n. 99/32 and GCN notice #433
  The refined position of GB991105 distributed in the BeppoSAX Mail n. 99/30 and GCN Circular 432 has been revised to:
  

   R.A. (2000) = 180.871
   DEC. (2000) = -66.757
  

  with the same error radius of 3.6'
• GCN notice #439
  Alberto Castro-Tirado, LAEFF-INTA (Madrid) and IAA-CSIC (Granada) Javier Gorosabel and Celia Sanchez-Fernandez, LAEFF-INTA (Madrid) Pam Kilmartin and John Hearnshaw, University of Canterbury Ian Bond, Nick Rattembury and Phil Yock, University of Auckland K. Ohnishi, Nagano National College of Technology and Marco Feroci, IAS (Frascati), on behalf of the BSAX team report:
  We have obtained six 10-minute exposures at the revised BeppoSAX WFC position for GRB 991105 (Piro et al. GCN 433) with the 0.61-m Mount John University Observatory (MJUO) telescope. The first set of images were taken on Nov 6.41 UT (17.1 hr after the GRB) through a broad band filter (R + I bandpass). The second one was obtained on Nov 7.37 UT with identical setup. After a visual comparison with the Digital Sky Survey and among the two co-added images, no sources varying by more than 0.3 mag were seen to the DSS limit (R about 21) within the BeppoSAX error box.
• GCN notice #441
  K. Hurley and T. Cline, on behalf of the NEAR GRB team, and M. Feroci, on behalf of the BeppoSAX GRB team, report:
  Although GRB991105 (GCN 433) was too weak to be observed by Ulysses, it was observed by NEAR. The preliminary IPN annulus for it is centered at RA=187.6492 deg., Decl.=-7.9319 deg. (J2000), and has a radius of 58.9882 +/- 0.0607 deg. (3 sigma). The annulus width is therefore about equal to the WFC error circle diameter, but it intersects it at:

  RA(2000)        Decl.(2000)
  12 h 03 m 52 s  -66 o  48' 13"
  12 h 02 m 59 s  -66 o  47' 30"
  

  and therefore reduces the WFC area slightly. A map may be found at ssl.berkeley.edu/ipn3/991105/. Some refinements to this annulus are expected which should further reduce the WFC error circle area.
• GCN notice #442
  R. M. Kippen, S. Phengshamnan & T. Giblin (University of Alabama in Huntsville) report on behalf of the BATSE GRB team:
  GRB 991105 was detected by BATSE on 1999 November 5.694963 UT as trigger number 7841. The event consisted of a complex series of pulses with two major episodes and significant spectral evolution. The T50 and T90 durations are 12.35 (-/+ 1.90) s and 48.64 (-/+ 1.36) s, respectively. The burst's peak flux (50-300 keV; integrated over 1.024 s) and fluence (>20 keV) are 1.98 (-/+ 0.06) photons cmE-2 sE-1 and 4.01 (-/+ 0.79) x 10E-6 erg cmE-2, respectively---ranking it in the top 20% (38%) of the BATSE burst flux (fluence) distribution. The average spectral hardness of the burst, as estimated by the ratio of 100-300 keV counts to those in the 50-100 keV range, is H32 = 0.83 (-/+ 0.01), which is average for bursts of this duration. The BATSE burst location is consistent with those measured by BeppoSAX (GCN 430) and the IPN (SAX/NEAR; GCN 411). The lightcurve for this event will be available shortly at: http://gammaray/batse/grb/lightcurve/
• GCN notice #449
  E. Palazzi, E. Pian, N. Masetti, F. Frontera (ITESRE, CNR, Bologna), E. Rol, P.M. Vreeswijk (U. of Amsterdam), P. McCarthy, H.-W. Chen, B. Schommer, C. Smith, N. Suntzeff (CTIO), H. Pedersen, J. Hjorth (CUO, Copenhagen), C. Kouveliotou (NASA-MSFC/USRA), T. Augusteijn, and R. Athreya (ESO) on behalf of the BeppoSAX and Amsterdam/Huntsville GRB optical follow-up teams, report:
  We have observed the revised BeppoSAX WFC error circle of GRB 991105 (Piro 1999, GCN 433) in the BRi bands at the ESO 2.2m telescope at La Silla (Chile) 15.8 and 39.9 hours after the burst.
  The field is very crowded as it lies on the Galactic plane. The reddening towards that direction is E(B-V) = 0.623 (Schlegel et al. 1998, ApJ 500, 525), implying a Galactic extinction of 2.7, 1.7 and 1.2 mag in B,R, and i, respectively. No galaxies are seen in the field, which is also indicative of considerable optical extinction.
  Photometric calibration was done using standard stars in the Landolt field SA98 (Landolt 1992, AJ 104, 340). The comparison between the two sets of images does not show any object with significant brightness variations larger than 0.5 mag down to the 3 sigma limiting magnitudes of R=23.5, B=22.5, i=22.0.
  We also observed the GRB field with the 4m telescope at CTIO (Chile), taking images in the R band over 4 nights starting 15 hours after the burst. SN search software has been applied to those images by N. Suntzeff and collaborators. No variables were detected in the field down to a 3 sigma limiting magnitude R=23.4, thus confirming the results from the ESO observations.