Intergalactic HeII absorption towards QSO 1157+3143

Abstract

We report the discovery of a further line of sight allowing detection of HeII Ly alpha 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 supressed by two intervening Lyman limit systems at z=2.77 and 2.94, but with the continuum flux recovering sufficiently shortward of ~ 1700 A 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 Ly alpha 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.

6 pages, 4 figures, accepted by A&A

References in corpus (8)

• The thermal history of the intergalactic medium
• The Evolution of the Effective Equation of State of the IGM
• Constraints on reionization from the thermal history of the intergalactic medium
• Resolving the Structure of Ionized Helium in the Intergalactic Medium with the Far Ultraviolet Spectroscopic Explorer
• The Fluctuating Intergalactic Radiation Field at Redshifts z = 2.3-2.9 from He II and H I Absorption towards HE 2347-4342
• Caught in the act: a helium-reionizing quasar near the line of sight to Q0302-003
• Detection of Intergalactic HeII Absorption at Redshift 3.5
• The Absorbers Toward CSO 118: Superclustering at {z~3}, or an Intrinsic Absorption Complex?

Cited by in corpus (38)

• The Physics of the Intergalactic Medium
• HeII Reionization and its Effect on the IGM
• Evolution of the Intergalactic Opacity: Implications for the Ionizing Background, Cosmic Star Formation, and Quasar Activity
• A Direct Precision Measurement of the Intergalactic Lyman-alpha Opacity at 2<z<4.2
• The SDSS-III Baryon Oscillation Spectroscopic Survey: The Quasar Luminosity Function from Data Release Nine
• Possible evidence for an inverted temperature-density relation in the intergalactic medium from the flux distribution of the Lyman-alpha forest
• Early and Extended Helium Reionization Over More Than 600 Million Years of Cosmic Time
• The photoheating of the intergalactic medium in synthesis models of the UV background
• The End of Helium Reionization at z~2.7 Inferred from Cosmic Variance in HST/COS HeII Lyman Alpha Absorption Spectra
• A New Constraint on the Escape Fraction in Distant Galaxies Using Gamma-ray Burst Afterglow Spectroscopy
• The History and Morphology of Helium Reionization
• The imprint of inhomogeneous HeII reionization on the HI and HeII Ly-alpha forest
• GALEX far-UV color selection of UV-bright high-redshift quasars
• The UV spectrum of HS1700+6416 II. FUSE observations of the HeII Lyman alpha forest
• Reionisation scenarios and the temperature of the IGM
• Photo-heating and the fate of hard photons during the reionisation of HeII by quasars
• Spatial fluctuations in the spectral shape of the UV background at 2<z<3 and the reionization of helium
• Quasars near the line of sight towards Q 0302-003 and the transverse proximity effect
• Statistical Detection of the HeII Transverse Proximity Effect: Evidence for Sustained Quasar Activity for $>$25 Million Years
• Inhomogeneous Helium Reionization and the Equation of State of the Intergalactic Medium
• The Evolution of the HeII-Ionizing Background at Redshifts 2.3<z<3.8 Inferred from a Statistical Sample of 24 HST/COS HeII Ly$\alpha$ Absorption Spectra
• Spectral shape of the UV ionizing background and HeII absorption at redshifts 1.8 < z < 2.9
• The evolution of the helium-ionizing background at z ~ 2-3
• The impact of helium reionization on the structure of the intergalactic medium
• Fluctuations in the Ionizing Background During and After Helium Reionization
• A High Yield of New Sightlines for the Study of Intergalactic Helium: Far-UV-Bright Quasars from SDSS, GALEX, and HST
• Large-Scale Fluctuations in the HeII Lyman-alpha Forest and HeII Reionization
• Helium reionization and the thermal proximity effect
• Ten More New Sightlines for the Study of Intergalactic Helium, and Hundreds of Far-UV-Bright Quasars, from SDSS, GALEX, and HST
• HST Spectral Observations near the He II Ly-alpha Break: Implications for He II Reionization
• Science with the World Space Observatory - Ultraviolet
• The HeII Lyman alpha forest and the thermal state of the IGM
• Probing reionization using quasar near-zones at redshift z ~ 6
• Quark-Novae, cosmic reionization, and early r-process element production
• Carbon ionization states and the cosmic far-UV background with HeII absorption
• Measuring photo-ionization rate and mean free path of HeII ionizing photons at $2.5\le z\le 3.6$: Evidence for late and rapid HeII reionization Part-II
• Helium reionization in the presence of self-annihilating clumpy dark matter
• Impact of Sommerfeld enhancement on helium reionization via WIMP dark matter