2005A&A...442...63R


C.D.S. - SIMBAD4 rel 1.7 - 2019.09.15CEST10:30:10

2005A&A...442...63R - Astronomy and Astrophysics, volume 442, 63-68 (2005/10-4)

Intergalactic HeII absorption towards QSO 1157+3143.

REIMERS D., FECHNER C., HAGEN H.-J., JAKOBSEN P., TYTLER D. and KIRKMAN D.

Abstract (from CDS):

We report the discovery of a further line of sight allowing detection of HeII Lyα absorption by the intergalactic medium. A HST/STIS survey of 32 bright z∼3 quasars selected from the Hamburg Quasar Surveys yielded one detection toward QSO 1157+3143 (z∼3, B≃17). A 10 orbit follow-up spectrum reveals a UV spectrum significantly suppressed by two intervening Lyman limit systems at z=2.77 and 2.94, but with the continuum flux recovering sufficiently shortward of ∼1700Å to allow study of the HeII absorption spectrum in the redshift range 2.75≤z≤2.97. The absorption is characterized by alternating voids and dense filament structures seen in both HeII and HI. Attempts to model the HeII opacity in terms of HI Lyα forest absorption are not successful in the voids, suggesting that HeII reionization is not complete between z=2.77 and 2.97 or that an optically thin Lyman limit system with z≃0.3 is responsible for the additional opacity.

Abstract Copyright:

Journal keyword(s): galaxies: quasars: individual: QSO 1157+3143 - galaxies: quasars: absorption lines - cosmology: observations

Simbad objects: 5

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Number of rows : 5

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2019
#notes
1 LBQS 0302-0019 QSO 03 04 49.8591748182 -00 08 13.537401746   18.08 17.80 17.5   ~ 227 0
2 QSO B1157+3143 QSO 12 00 06.2494598212 +31 26 30.839054589   16.76 16.47     ~ 55 0
3 HS 1700+6416 QSO 17 01 00.6195618802 +64 12 09.118927057   16.39 16.17     ~ 327 0
4 QSO B1935-692 QSO 19 40 25.5273425126 -69 07 56.972951491   18.36 18.8     ~ 98 1
5 QSO B2347-4342 QSO 23 50 34.2595236845 -43 25 59.680334378   16.3 16.3     ~ 156 0

    Equat.    Gal    SGal    Ecl

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2019.09.15-10:30:10

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