Details

Autor(en) / Beteiligte

• Tanvir, N R
• LeVan, A J
• Fruchter, A S
• Fynbo, J P U
• Hjorth, J
• Wiersema, K
• Bremer, M N
• Rhoads, J
• Jakobsson, P
• O'Brien, P T

Titel

STAR FORMATION IN THE EARLY UNIVERSE: BEYOND THE TIP OF THE ICEBERG

Ist Teil von

• The Astrophysical journal, 2012-07, Vol.754 (1), p.1-13

Ort / Verlag

United States

Erscheinungsjahr

2012

Link zum Volltext

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• We present late-time Hubble Space Telescope (HST) imaging of the fields of six Swift gamma-ray bursts (GRBs) lying at 5.0 [lap] z [lap] 9.5. Our data include very deep observations of the field of the most distant spectroscopically confirmed burst, GRB 090423, at z = 8.2. Using the precise positions afforded by their afterglows, we can place stringent limits on the luminosities of their host galaxies. None of the others are significantly detected, meaning that all the hosts lie below L* at their respective redshifts, with star formation rates (SFRs) [lap] 4 M sub([middot in circle]) yr super(-1) in all cases. Indeed, stacking the five fields with WFC3-IR data, we conclude a mean SFR < 0.17 M sub([middot in circle]) yr super(-1) per galaxy. These results support the proposition that the bulk of star formation, and hence integrated UV luminosity, at high redshifts arises in galaxies below the detection limits of deep-field observations.