LINE-EMITTING GALAXIES BEYOND A REDSHIFT OF 7: AN IMPROVED METHOD FOR ESTIMATING THE EVOLVING NEUTRALITY OF THE INTERGALACTIC MEDIUM

By M. Schenker, Richard S. Ellis, N. Konidaris, D. Stark. 2014

197 citations recorded by the source corpus.

The redshift-dependent fraction of color-selected galaxies revealing Lyman alpha (Lyα) emission, xLyα has become the most valuable constraint on the evolving neutrality of the early intergalactic medium. However, in addition to resonant scattering by neutral gas, the visibility of Lyα is also dependent on the intrinsic properties of the host galaxy, including its stellar population, dust content, and the nature of outflowing gas. Taking advantage of significant progress we have made in determining the line-emitting properties of z ≃ 4–6 galaxies, we propose an improved method, based on using the measured slopes of the rest-frame ultraviolet continua of galaxies, to interpret the growing body of near-infrared spectra of z > 7 galaxies in order to take into account these host galaxy dependencies. In a first application of our new method, we demonstrate its potential via a new spectroscopic survey of 7 < z < 8 galaxies undertaken with the Keck MOSFIRE spectrograph. Together with earlier published data, our data provide improved estimates of the evolving visibility of Lyα, particularly at redshift z ≃ 8. As a by-product, we also present a promising new line-emitting galaxy candidate, detected at 4.0σ at redshift z = 7.62. We discuss the improving constraints on the evolving neutral fraction over 6 < z < 8 and the implications for cosmic reionization.

Subfields: Astronomy and Astrophysics, Electrical and Electronic Engineering, Instrumentation

View Paper: https://www.semanticscholar.org/paper/f3a8096e9d0ad180c3afc388ba22cf40396313d0

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In Astronomy and Astrophysics

1. Richard S. Ellis
2. R. Bouwens
3. P. Oesch
4. G. Illingworth
5. L. Hernquist
6. J. Dunlop
7. M. Franx
8. P. V. van Dokkum

In Electrical and Electronic Engineering

1. Richard S. Ellis
2. R. Bouwens
3. P. Oesch
4. D. Stark
5. G. Illingworth
6. J. Dunlop
7. I. Labbé
8. M. Franx

In Instrumentation

1. Richard S. Ellis
2. R. Bouwens
3. M. Franx
4. P. Oesch
5. P. V. van Dokkum
6. G. Illingworth
7. J. Dunlop
8. I. Labbé

Citations in the corpus

• Lyman-α spectral properties of five newly discovered Lyman continuum emitters (2016, background): “Observations also witness a sudden transition in the evolution of the Lyα properties of galaxies with redshift: the fraction of Lyα emitting galaxies among LBGs increases regularly with redshift, up to z ∼ 6 where a sharp decrease is observed (e.g. Schenker et al. 2014).”
• ARE ULTRA-FAINT GALAXIES AT z = 6–8 RESPONSIBLE FOR COSMIC REIONIZATION? COMBINED CONSTRAINTS FROM THE HUBBLE FRONTIER FIELDS CLUSTERS AND PARALLELS (2015, background): “Indeed, the increasing neutral hydrogen fraction at z > 6 easily absorbs and diffuses Lyα photons(Atek et al. 2009; Stark et al. 2010; Caruana et al. 2014; Schenker et al. 2014b).”
• Feedback-regulated star formation and escape of LyC photons from mini-haloes during reionization (2016, background): “…spectra of 5<∼ z <∼ 6 QSOs (Becker et al. 2015) and the observed rapid evolution of Lyα emitters at z > 6 (Ono et al. 2012; Caruana et al. 2014; Schenker et al. 2014; Pentericci et al. 2014; Tilvi et al. 2014; Matthee et al. 2015) suggest that reionisation may have ended later than…”
• Identification of the brightest Lyα emitters at z = 6.6 : Implications for the evolution of the luminosity function in the reionization era (2015, methodology): “…2014; Caruana et al. 2014), indicating either a lower intrinsic escape of Lyα (e.g. Dijkstra et al. 2014), an increased column density of absorbing clouds (Bolton & Haehnelt 2013), or a higher neutral fraction of the IGM (Santos 2004; Dijkstra et al. 2007; Schenker et al. 2014; Taylor & Lidz 2014).”
• The Universe Is Reionizing at z ∼ 7: Bayesian Inference of the IGM Neutral Fraction Using Lyα Emission from Galaxies (2017, background): “…(e.g. Fontana et al. 2010; Stark et al. 2010; Caruana et al. 2012; Treu et al. 2013; Caruana et al. 2014; Faisst et al. 2014; Tilvi et al. 2014; Schenker et al. 2014; Pentericci et al. 2014), as well as an evolving Lyα luminosity function (e.g., Ouchi et al. 2010; Zheng et al. 2017; Ota et…”
• COSMIC REIONIZATION AND EARLY STAR-FORMING GALAXIES: A JOINT ANALYSIS OF NEW CONSTRAINTS FROM PLANCK AND THE HUBBLE SPACE TELESCOPE (2015, background): “…star forming galaxies showing Lymanα emission (e.g., Stark et al. 2010) now extended to z ∼ 7 − 8 from Treu et al. (2013), Pentericci et al. (2014) and Schenker et al. (2014), the Lyman-α damping wing absorption constraints from GRB host galaxies by Chornock et al. (2013), and the number of dark…”
• REIONIZATION AFTER PLANCK: THE DERIVED GROWTH OF THE COSMIC IONIZING EMISSIVITY NOW MATCHES THE GROWTH OF THE GALAXY UV LUMINOSITY DENSITY (2015, background): “…the better study of bright quasars and improved statistics on Lyα emission in normal star-forming galaxies, to better probe the ionization state of the z = 6–9 universe (e.g., Mortlock et al. 2011; Ono et al. 2012; Pentericci et al. 2014 [P14]; Caruana et al. 2014; Schenker et al. 2014 [S14]).”
• Ultraviolet emission lines in young low-mass galaxies at z ≃ 2: physical properties and implications for studies at z > 7 (2014, background): “Asa result of the attenuation of Lyα in z ≃ 7 galaxies (e.g., Schenker et al. 2012, Ono et al. 2012, Pentericci et al. 2012, Treu et al. 2013, Schenker et al. 2014), these UV emission lines likely provide our best hope of confirming very high redshift galaxies with groundbased facilities.”
• Spectroscopic detections of C iii] λ1909 Å at z ≃ 6–7: a new probe of early star-forming galaxies and cosmic reionization (2014, methodology): “As described in §1, the Lyα emitter fraction appears to drop rapidly over 6 < z < 8 (e.g., Ono et al. 2012; Treu et al. 2013; Pentericci et al. 2014; Schenker et al. 2014; Tilvi et al. 2014), as might be expected if the IGM is partially neutral at z ' 7− 8.”
• Spectroscopic detection of C iv λ1548 in a galaxy at z = 7.045: implications for the ionizing spectra of reionization-era galaxies (2015, background): “While Lyα emission is very common among z ' 6 galaxies (Stark et al. 2011), it is exceedingly rare at z ' 7 (e.g., Treu et al. 2013; Schenker et al. 2014; Tilvi et al. 2014).”
• Can the intergalactic medium cause a rapid drop in Lyα emission at z > 6? (2014, methodology): “9 in Schenker et al. (2014), their claimed evolution of z = 6 → 8 is inconsistent with IGM attenuation by more than 5σ, while non-Bayesian upper limits at z ≈ 8 (e.g. Treu et al. 2013; Tilvi et al. 2014) are fully consistent with no evolution over this redshift range. c© 0000 RAS, MNRAS 000, 000–000”
• The THESEUS space mission concept: science case, design and expected performances (2017, methodology): “ation et al. 2016), whereas the observations of the Gunn-Peterson trough in the spectra of distant quasars and galaxies indicate it was largely finished by z˘6.5 (see, e.g., Caruana et al. 2012, 2014; Schenker et al. 2014). Statistical measurements of the fluctuations in the redshifted 21 cm line of n”
• Radiation Backgrounds at Cosmic Dawn: X-Rays from Compact Binaries (2016, background): “2015), the dark pixel statistics (McGreer et al. 2015), and the swift drop observed in the space density of Lyα emitting galaxies at z > 6 (e.g. Choudhury et al. 2015; Schenker et al. 2014).”
• CONTRASTING GALAXY FORMATION FROM QUANTUM WAVE DARK MATTER, ψDM, WITH ΛCDM, USING PLANCK AND HUBBLE DATA (2015, background): “Recent observations indicate that reionization undergoes a rapid evolution at < <z6 8 and is completed at ~z 6 (Fan et al. 2006; Schroeder et al. 2013; Schenker et al. 2014; McGreer et al. 2015).”
• Inferences on the timeline of reionization at z ∼ 8 from the KMOS Lens-Amplified Spectroscopic Survey (2019, methodology): “…equivalent width (EW) distribution, decreases rapidly (e.g., Fontana et al. 2010; Pentericci et al. 2011; Caruana et al. 2012; Treu et al. 2012, 2013; Ono et al. 2012; Caruana et al. 2014; Pentericci et al. 2014; Schenker et al. 2014; Tilvi et al. 2014; Faisst et al. 2014; Jung et al. 2018).”
• SILVERRUSH. IV. Lyα luminosity functions at z = 5.7 and 6.6 studied with ∼1300 Lyα emitters on the 14–21 deg2 sky (2017, background): “The studies of Lyα emitting fractions indicate xHI & 0.5 at z ∼ 7 (e.g., Pentericci et al. 2011; Schenker et al. 2012; Ono et al. 2012; Treu et al. 2012; Caruana et al. 2012; Caruana et al. 2014; Pentericci et al. 2014; Schenker et al. 2014).”
• Using Lyman-α to detect galaxies that leak Lyman continuum (2014, background): “The evolution of the number of Lyα emitting galaxies among the population of LBGs with a sudden drop at z > 6 (Stark et al. 2010; Ono et al. 2012; Schenker et al. 2014) is usually interpreted as due to an increase of the neutral fraction of the IGM.”