Quasars with HeII absorption (Reionisation)

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Introduction

The small number of QSOs with HeII absorption is a byproduct of the high redshift (z > 2.8) for HST to observe the 304 \AA line and the scarcity of lines of sight free of intervening DLAs (few percent at z=3.

Quasars with HeII absorption

  • Q0302-003 3.2935 \pm 0.0006
  • PKS 1935-692 3.154 \pm 0.001
  • QSO 1157+3143 2.989 \pm 0.001
  • HE 2347-4342 2.885 \pm 0.005
  • HS 1700+6416 2.736 \pm 0.001

Display a trough with interupted absorption

  • Q0302-003 3.2935 \pm 0.0006
  • PKS 1935-692 3.154 \pm 0.001
  • QSO 1157+3143 2.989 \pm 0.001
  • HE 2347-4342 2.885 \pm 0.005

Dispay weak absorption, matching the HI forest

  • HE 2347-4342 2.885 \pm 0.005
  • HS 1700+6416 2.736 \pm 0.001

References by object

  • HE 2347-4342 2.885 \pm 0.005
    • Reimers97 1997A&A...327..890R
  • Q0302-003
    • Heap00 2000ApJ...534...69H
    • JJWR03: Jakobsen, Jansen, Wagner, Reimers 2003A&A...397..891J
  • HE 2347-4342
    • DKZ96 1996Natur.380...47D
  • QSO 1157+3143
    • Reimers05 2005A&A...442...63R

HE 2347-4342

HE2347-4342 HeII forest.gif

Section of the GHRS spectrum and error spectrum (dotted curve) of HE 2347-4342 with the flux given in 10-15 erg s-1 cm-2 Å-1. The expected position of the He II 303.78 Å edge for a QSO redshift of z=2.885 is indicated by the vertical dashed line. (Reimers97)


Q0302-003 and PKS 1935-692

Q0302-003 HeII forest.gif Comparison of the He II Gunn-Peterson absorption trough plotted as a function of redshift for the He II line at 303.78 Å. Q0302-003 and PKS 1935-692 were observed with STIS, and HE 2347-4342 by GHRS. The downward arrows denote the redshift of the QSO. As in Fig. 4, the spectral region near geocoronal Lyα is grayed out. In the case of PKS 1935-692, which has an intervening damped Lyα system at z = 0.30, the predicted absorption spectrum from the DLA is also shown in gray as a warning that the opacity at z < 3 should not be interpreted as Gunn-Peterson absorption. (Heap00)

Q0302-003 low opacity feature.gif Comparison in redshift between the measured emission redshift of QSO 03020-0014 (cross) and the isolated low opacity HeII feature at z\simeq 3.056 seen in the STIS spectrum of Q0302-003 (binned full line). The dotted curve denotes the 1σ statistical uncertainty per pixel of the STIS spectrum. (JJWR03)

Q0302-003 z=3.286 HeII Lya Jakobsen.gif Q0302-003 at z=3.286 (Peter Jakobsen)

HS 1700+6416

The helium absorption is referenced in a Nature article to which I don't have access.

QSO 1157+3143

QSO1157+3143 HeII forest.gif

HeII 304 \AA absorption in QSO 1157+3143.

AKA: HS 1157+3143, SDSS J120006.26+312630.9

--Etittley 14:38, 27 June 2007 (BST) Back to Reionisation

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