Effective absorbing column density in the gamma-ray burst afterglow X-ray spectra

May 16, 2014
6 pages
Published in:
  • Mon.Not.Roy.Astron.Soc. 441 (2014) 4, 3634-3639
  • Published: Jul 11, 2014
e-Print:

Citations per year

20142016201820202022102
Abstract: (Oxford University Press)
We investigate the scaling relation between the observed amount of absorption in the X-ray spectra of gamma-ray burst afterglows and the absorber redshift. Through dedicated numerical simulations of an ideal instrument, we establish that this dependence has a power-law shape with index 2.4. However, for real instruments, this value depends on their low-energy cut-off, spectral resolution and on the detector spectral response in general. We thus provide appropriate scaling laws for specific instruments. Finally, we discuss the possibility to measure the absorber redshift from X-ray data alone. We find that 10^5-10^6 counts in the 0.3–10 keV band are needed to constrain the redshift with 10 per cent accuracy. As a test case, we discuss the XMM–Newton observation of GRB 090618 at z = 0.54. We are able to recover the correct redshift of this burst with the expected accuracy.
Note:
  • MNRAS accepted. 6 figures. 3 tables
  • gamma-ray burst: general
  • gamma-ray burst: individual: GRB 090618
  • X-rays: general
  • X-rays: ISM