Detection of GRB 060927 at z=5.47: Implications for the use of gamma-ray bursts as probes of the end of the dark ages

Ruiz-Velasco, A.; Swan, H.; Troja, E.; Malesani, D.; Fynbo, J.; Starling, R.; Xu, D.; Aharonian, F.; Akerlof, C.; Andersen, M.; Ashley, M.; Barthelmy, S.; Bersier, D.; Ceron, J.; Castro-Tirado, A.; Gehrels, N.; Goegues, E.; Gorosabel, J.; Guidorzi, C.; Guever, Tolga; Hjorth, J.; Horns, D.; Huang, K.; Jakobsson, P.; Jensen, B.; Kiziloglu, Ue.; Kouveliotou, C.; Krimm, H.; Ledoux, C.; Levan, A.; Marsh, T.; McKay, T.; Melandri, A.; Milvang-Jensen, B.; Mundell, C.; O'Brien, P.; Oezel, M.; Phillips, A.; Quimby, R.; Rowell, G.; Rujopakarn, W.; Rykoff, E.; Schaefer, B.; Sollerman, J.; Tanvir, N.; Thoene, C.; Urata, Y.; Vestrand, W.; Vreeswijk, P.; Watson, D.; Wheeler, J.; Wijers, R.; Wren, J.; Yost, S.; Yuan, F.; Zhai, M.; Zheng, W.

doi:10.1086/521546

Detection of GRB 060927 at z=5.47: Implications for the use of gamma-ray bursts as probes of the end of the dark ages

Atıf İçin Kopyala

Ruiz-Velasco A. E., Swan H., Troja E., Malesani D., Fynbo J. P. U., Starling R. L. C., ...Daha Fazla

ASTROPHYSICAL JOURNAL, cilt.669, sa.1, ss.1-9, 2007 (SCI-Expanded)

Yayın Türü: Makale / Tam Makale
Cilt numarası: 669 Sayı: 1
Basım Tarihi: 2007
Doi Numarası: 10.1086/521546
Dergi Adı: ASTROPHYSICAL JOURNAL
Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
Sayfa Sayıları: ss.1-9
İstanbul Üniversitesi Adresli: Evet

Özet

We report on follow-up observations of the gamma-ray burst GRB 060927 using the robotic ROTSE-IIIa telescope and a suite of larger aperture ground-based telescopes. An optical afterglow was detected 20 s after the burst, the earliest rest-frame detection of optical emission from any GRB. Spectroscopy performed with the VLT about 13 hr after the trigger shows a continuumbreak at lambda approximate to 8070 angstrom, produced by neutral hydrogen absorption at z approximate to 5.6. We also detect an absorption line at 8158 angstrom, which we interpret as Si II lambda 1260 at z = 5. 467. Hence, GRB 060927 is the second most distant GRB with a spectroscopically measured redshift. The shape of the red wing of the spectral break can be fitted by a damped Ly alpha profile with a column density with log (N-H/cm(-2)) = 22-50 +/- 0.15. We discuss the implications of thiswork for the use ofGRBs as probes of the end of the dark ages and draw threemain conclusions: (1) GRB afterglows originating from z less than or similar to 6 should be relatively easy to detect from the ground, but rapid near-infrared monitoring is necessary to ensure that they are found; (2) the presence of large H I column densities in some GRB host galaxies at z > 5 makes the use of GRBs to probe the reionization epoch via spectroscopy of the red damping wing challenging; and ( 3) GRBs appear crucial to locate typical star-forming galaxies at z > 5, and therefore the type of galaxies responsible for the reionization of the universe.