Probing the Ionization State of the Universe at z > 6

By R. White, Robert H. Becker, Xiaohui Fan, M. Strauss. 2003

255 citations recorded by the source corpus.

We present high signal-to-noise ratio Keck ESI spectra of the two quasars known to have Gunn-Peterson absorption troughs, SDSS J1030+0524 (z = 6.28) and SDSS J1148+5251 (z = 6.37). The Lyα and Lyβ troughs for SDSS J1030+0524 are very black and show no evidence of any emission over a redshift interval of ∼0.2, starting at z = 6. On the other hand, SDSS J1148+5251 shows a number of emission peaks in the Lyβ Gunn-Peterson trough along with a single weak peak in the Lyα trough. The Lyα emission has corresponding Lyβ emission, suggesting that it is indeed a region of lower optical depth in the intergalactic medium at z = 6.08. The stronger Lyβ peaks in the spectrum of SDSS J1148+5251 could also conceivably be the result of "leaks" in the intergalactic medium (IGM), but we suggest instead that they are Lyα emission from an intervening galaxy at z = 4.9. This hypothesis gains credence from a strong complex of C IV absorption at the same redshift and from the detection of continuum emission in the Lyα trough at the expected brightness. If this proposal is correct, the quasar light has probably been magnified through gravitational lensing by the intervening galaxy. The Strömgren sphere observed in the absorption spectrum of SDSS J1148+5251 is significantly smaller than expected on the basis of its brightness, which is consistent with the hypothesis that the quasar is lensed. If our argument for lensing is correct, the optical depths derived from the troughs of SDSS J1148+5251 are only lower limits [albeit still quite strong, with τ(Lyα) > 16 inferred from the Lyβ trough]. The Lyβ absorption trough of SDSS J1030+0524 gives the single best measurement of the IGM transmission at z > 6, with an inferred optical depth of τ(Lyα) > 22.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/33285cabfe7f95094b5ddc22b6006c33b29d53f6

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

Citations in the corpus

Observational Constraints on Cosmic Reionization (2006, background): “Wyithe & Loeb (2005a) further showed that the Gunn-Peterson optical depth variations to be of order unity on a scale of ∼ 100 comoving Mpc.”
UV Luminosity Functions at z~4, 5, and 6 from the Hubble Ultra Deep Field and Other Deep Hubble Space Telescope ACS Fields: Evolution and Star Formation History (2007, background): “…ionizing radiation output of high-redshift galaxies since it was discovered that hydrogen remains almost entirely ionized since a redshift of z ∼ 6 (Becker et al. 2001; Fan et al. 2002; White et al. 2003; Fan et al. 2006) and that galaxies are the only obvious candidates to produce this radiation.”
Self-regulated reionization (2006, methodology): “…help explain why the CMB polarization experiments indicate that reionization was well advanced byz >∼ 11 (Spergel & et al. 2006), while quasar absorption spectra suggest that reionization ended later, atz ∼ 6.5 (e.g. Fan et al. 2002; White et al. 2003), implying that the EOR was extended in time.”
Statistical Probes of Reionization with 21 Centimeter Tomography (2004, background): “Evidence for this Gunn & Peterson (1965) effect has been found near z∼ 6.5 (Becker et al. 2001; White et al. 2003).”
The Growth of H II Regions During Reionization (2004, background): “Observations of Lyα absorption in the spectra of high-redshift quasars indicate that reionization ends at z ∼ 6.5 (Becker et al. 2001; Fan et al. 2002; White et al. 2003; Wyithe & Loeb 2004), although this interpretation is controversial (Songaila 2004).”
Foreground simulations for the LOFAR-epoch of reionization experiment (2008, background): “…depth in the Gunn–Peterson troughs (Gunn & Peterson 1965) observed in the Sloan Digital Sky Survey quasar spectra (Becker et al. 2001; Fan et al. 2001; Pentericci et al. 2002; White et al. 2003; Fan et al. 2006), marking a lower limit to the redshift at which the Universe became completely ionized.”
Mapping Neutral Hydrogen during Reionization with the Lyα Emission from Quasar Ionization Fronts (2007, unknown): “…in terms of its counterpart obtained assuming an infinite speed of light, vI;NR(rI), by the relation vI(rI) ¼ vI;NR(rI) 1þ vI;NR(rI)=c ; ð11Þ regardless of the difference in physical times at which the I-front reaches the radius rI (Shapiro et al. 2006; see also White et al. 2003 & Yu 2005).”
Black Hole Masses and Enrichment of z ~ 6 SDSS Quasars (2007, background): “If the quasar is located in a region overdense by a factor D, the radius is reduced by D−1/3 (White et al. 2003).”
The First Cosmic Structures and Their Effects (2004, background): “…Telescope) (Pentericci et al. 2002) spectra of the Sloan Digital Sky Survey quasars SDSS J1030-0524 at z = 6.28, and SDSS J1148+5251 at z = 6.37 (White et al. 2003) might indicate that the universe is approaching the reionization epoch at z ≈ 6, consistent also with the dramatic increase in the…”
The Evolution of Optical Depth in the Lyα Forest: Evidence Against Reionization at z~6 (2006, unknown): “Perhaps the most dramatic inferences drawn from the evolution of Lyα transmitted flux is that the reionization of the IGM may have ended as late as z ∼ 6.2 (Becker et al. 2001; White et al. 2003; Fan et al. 2002, 2006).”
The morphology of H ii regions during reionization (2006, background): “Observations of high-redshift quasars, gamma-ray bursts and Lyα emitters are currently probing redshifts at which the Universe may have been significantly neutral (Becker et al. 2001; White et al. 2003; Santos et al. 2004; Fan et al. 2006; Kashikawa 2006; Totani et al. 2006).”
Model-independent evidence in favour of an end to reionization by z ≈ 6 (2014, methodology): “This includes masking Lyα absorption within the Lyβ forest, as 2 The ESI spectra used in Paper I, reduced using the method described in White et al. (2003), do present highly Gaussian noise properties according to this test. any DLA at these wavelengths would masquerade as Lyβ dark pixels.”
Constraining the Evolution of the Ionizing Background and the Epoch of Reionization with z ∼ 6 Quasars. II. A Sample of 19 Quasars (2005, methodology): “The GP trough detected in the spectrum of SDSS J1030+0524 (z = 6.28, Fan et al. 2001, Becker et al. 2001, White et al. 2003) shows complete absorption in the Lyα, β and γ transitions.”
Four Quasars above Redshift 6 Discovered by the Canada-France High-z Quasar Survey (2007, background): “…are detected towards SDSS J1044-0125 atz = 2.2786 and SDSS J1306+0356 at z = 2.20 and 2.53, while there is no MgII absorption towards SDSS J0836+0054, SDSS J1030+0524 and SDSS J1148+5251 (Becker et al. 2001; Djorgovski et al. 2001; Fan et al. 2003; White et al. 2003; Ryan-Weber et al. 2006).”
The Giant Gemini GMOS survey of zem > 4.4 quasars – I. Measuring the mean free path across cosmic time (2014, background): “Analysis of these data suggest that the transition to a predominantly ionized Universe occurs at z 6 (White et al. 2003; Bolton et al. 2011), where a sharp increase in the effective Lyα opacity may occur (but see Becker, Rauch & Sargent 2007).”
The FIRST-2MASS Red Quasar Survey (2007, background): “…of red quasars has challenged the view that all quasars are blue, UV-luminous sources and suggests that a large population of quasars with red colors exists (Webster et al. 1995; Cutri et al. 2001; Gregg et al. 2002; Richards et al. 2003; White et al. 2003b; Glikman et al. 2004, hereafter Paper I).”