{
  "bibcode": "2004GCN..2897....1F",
  "body": "P. Ferrero (IASF/CNR- Bologna/ Osservatorio e Universita' di Teramo),\nG. Pizzichini (IASF/CNR- Bologna), G. Greco, C. Bartolini, A. Guarnieri, \nand A. Piccioni(Universita' di Bologna), and R.Gualandi (INAF/ Bologna Observatory)\nreport:    \n   \nWe observed the optical afterglow of INTEGRAL GRB 041218 (Mereghetti et \nal.,GCN 2858) detected by Torii (GCN 2860) and Gorosabel et al. (GCN \n2861), using the 152 cm telescope in Loiano (Bologna University) on \nDecember, 18 (Greco et al., GCN 2863) in clear sky conditions and strong \nwinds (seeing ~3).\n\nOur photometric analysis of the images gives the following results:\n\n----------------------------------------------------\nFilter     UT mean         magOT            exp\n----------------------------------------------------\nRc         Dec 18.758    19.74 +- 0.07      600s\nRc         Dec 18.765    19.74 +- 0.06      600s\nRc         Dec 18.781    20.04 +- 0.07      600s\nRc         Dec 18.792    20.27 +- 0.07      600s\nRc         Dec 18.800    20.58 +- 0.09      600s\nRc         Dec 18.807    20.45 +- 0.09      600s\nRc         Dec 18.814    20.64 +- 0.09      600s\nRc         Dec 18.824    20.63 +- 0.09      600s\nRc         Dec 18.840    20.81 +- 0.08      2x600s\nRc         Dec 18.854    20.90 +- 0.10      2x600s\nRc         Dec 18.872    20.75 +- 0.09      3x600s\nV          Dec 18.906    >19.1 (1 sigma)    600s\nRc         Dec 18.913    >21   (1 sigma)    600s\nB          Dec 18.895       >20.4           600s\n----------------------------------------------------\n\nIn the time interval of our observations we find the same decay index \nalpha = 1.4 given by D'Avanzo et al., GCN 2879, with the possible \nexception of the Rc magnitude at UT 18.872, which is however still within \n3 sigmas of the extrapolation from the other points.\n\nThe following stars have been used:\n\nR.A.: 24.853910   Decl.:+71.385923\nR.A.: 24.801607   Decl.:+71.360825\nR.A.: 24.831858   Decl.:+71.343547  \nfor Rc photometry;\nR.A.: 24.909680   Decl.:+71.278967\nfor V upper limit   (Henden, GCN 2869); \n\nR.A.: 24.903450   Decl.:+71.379872\nfor B upper limit (USNOA.2).\n\n \n\nThis message can be quoted.",
  "circularId": 2897,
  "createdOn": 1103822742000,
  "email": "pizzichini@bo.iasf.cnr.it",
  "subject": "GRB 041218: optical observations",
  "submitter": "Graziella Pizzichini at IASF/CNR,Bologna  <pizzichini@bo.iasf.cnr.it>",
  "eventId": "GRB 041218"
}