Disclosing the gamma-ray burst circumburst ambient with XMM-Newton

Long GRBs signal the death of massive stars. Their afterglow emission can beused to probe the progenitor ambient through a detailed study of the absorptionpattern. This is done at optical wavelengths with impressive results. Detailedstudies of the absorption pattern imprinted in the X ray spectrum by thecircumburst material can be carried out, allowing us to shed light on thematerial metallicity, composition and distance of the absorber. We propose tocontinue observing bright Swift GRBs within 9 hr to derive with highersignificance an unbiased characterization of the circumburst material. For verybright GRBs we can also search for WHIM features using the GRB as a lighthouse. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]