Gamma-ray Burst 001011

(All information courtesy of the instrument teams.)

Previous IAU Circulars

• none

• GCN notice #846 = BeppoSAX MAIL n. 00/25
  On Oct. 11, 15:54:50 U.T. a GRB (GRB001011) has been detected simultaneosly by the GRBM and WFC2 aboard BeppoSAX.
  Preliminary coordinates from WFC are:

  R.A.(2000)= 275.865
  DEC(2000)= -50.902
  

  The error radius at this stage of analysis is 5'.
  We are planning a BeppoSAX-NFI observation.
• GCN notice #847 = BeppoSAX MAIL n. 00/26
  Refined coordinates of GRB001011 from WFC are:

  R.A.(2000)= 275.768
  DEC.(2000)= -50.899
  

  The error radius is 2'.
  A BeppoSAX/NFI follow-up observation is not feasible due to the presence of the moon in one of the startrackers of the satellite.
• GCN notice #849
  J. Gorosabel (DSRI, Copenhagen), J. Hjorth (U. of Copenhagen and OMP, Toulouse), H. Pedersen, B. L. Jensen (U. of Copenhagen), J. P. U. Fynbo (ESO), M. I. Andersen (U. of Oulu), J. Greiner (AIP, Potsdam), A. J. Castro-Tirado (LAEFF-INTA, Madrid and IAA-CSIC, Granada), E. Pian (Astr. Obs., Trieste and ITESRE-CNR, Bologna), P. Vreeswijk, E. van den Heuvel (U. of Amsterdam), M. A. Treyer (LAM, Marseille), G. Mallen-Ornelas (U. of Toronto) report on behalf of a joint afterglow network:
  We have performed R, J and Ks-band observations of the GRB 001011 error box (Gandolfi et al. GCN #846) with the 1.54-m Danish and the 3.58-m New Technology Telescope (NTT) at ESO, La Silla as follows:
  

          Date (UT)       Telescope (Instr.)    Texp (s)  Filter
    ------------------------------------------------------------
    Oct. 11.963 - 11.967      NTT (SOFI)        15 x 60     Ks
    Oct. 11.967 - 11.982      NTT (SOFI)        15 x 60     J
    Oct. 11.983 - 12.000      NTT (SOFI)        15 x 60     Ks
    Oct. 11.993 - 12.036    1.54-m (DFOSC)      5 x 600     R 
    Oct. 14.003 - 14.052    1.54-m (DFOSC)      5 x 600     R
    ------------------------------------------------------------
  

  A comparison of the two sets of R-band images reveals a fading object (not present in the DSS-2) located at:

    RA(J2000)  =  18h 23m 04.6s
    Dec(J2000) = -50d 54' 16"
  

  with an uncertainty of 2". This location is consistent with the refined BeppoSAX WFC position (GCN #847). Preliminary aperture photometry yields for the optical transient:

   R = 20.6 +- 0.1 on Oct. 12.014 UT
   R = 23.5 +- 0.4 on Oct. 14.027 UT
  

  The zero point is based on the USNO-A2.0 star located at RA(J2000) = 18h 23m 1.658s, Dec(J2000) = -50d 54' 17.24" with magnitude R = 18.0.
  The object is also clearly detected in the J and Ks-band images.
  Given the location of the transient in the WFC error box, its absence in the DSS-2, and a power-law decay index of -1.4 which is typical of GRB afterglows, it is likely that the transient is the optical/infrared afterglow of GRB 001011.
  Finding charts can be found at: http://www.dsri.dk/~jgu/grb001011/
  We acknowledge the assistance from L. Vanzi, N. Ageorges, and H. Jones at La Silla.
  

  1.54-m Danish Telescope on Oct. 11.99-12.03 UT: R-band, Texp=5 x 600-s.

  

  1.54-m Danish Telescope on Oct. 14.00-14.05 UT: R-band, Texp=5 x 600-s.