RAPID DECLINE OF Lyα EMISSION TOWARD THE REIONIZATION ERA

Tilvi, Vithal; Papovich, Casey; Finkelstein, Steven L.; Long, James P.; Song, Mimi; Dickinson, Mark; Ferguson, Henry C.; Koekemoer, Anton M.; Giavalisco, Mauro; Mobasher, Bahram

doi:10.1088/0004-637x/794/1/5

Cited by 200 publications

(234 citation statements)

References 74 publications

(146 reference statements)

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“…0.35 at z ∼ 7 and z ∼ 8, respectively, in agreement with the measurements of declining Lyman alpha emission fraction of high-redshift galaxies (Stark et al 2010;Treu et al 2013;Faisst et al 2014;Pentericci et al 2014;Schenker et al 2014;Tilvi et al 2014; see also the solid pentagons in Fig. 10).…”

Section: Other Reionization Constraintssupporting

confidence: 87%

“…Reionization is relatively wellconstrained to be completed at z 6 by analysis of the Gunn-Peterson effect (Gunn & Peterson 1965) in the spectra of high-redshift QSOs (e.g., Fan et al 2006;Willott et al 2007;Bolton et al 2011;McGreer et al 2015) and gammaray bursts (GRBs, e.g., Chornock et al 2013). Preliminary measurements of the IGM neutral fraction at z ∼ 7-8 have been made using the Lyα emission fraction of star-forming galaxies (e.g., Stark et al 2010;Treu et al 2013;Pentericci et al 2014;Tilvi et al 2014;Faisst et al 2014;Schenker et al 2014). On the other hand, the integrated Thomson scattering optical depth, τes, due to the scattering of CMB photons off free electrons after reionization, places an important integral constraint on the extended reionization history.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Constraints on the star formation efficiency of galaxies during the epoch of reionization

Sun

Furlanetto

2016

Mon. Not. R. Astron. Soc.

183

157

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Reionization is thought to have occurred in the redshift range of 6 < z < 9, which is now being probed by both deep galaxy surveys and CMB observations. Using halo abundance matching over the redshift range 5 < z < 8 and assuming smooth, continuous gas accretion, we develop a model for the star formation efficiency f of dark matter halos at z > 6 that matches the measured galaxy luminosity functions at these redshifts. We find that f peaks at ∼ 30% at halo masses M ∼ 10 11 -10 12 M , in qualitative agreement with its behavior at lower redshifts. We then investigate the cosmic star formation histories and the corresponding models of reionization for a range of extrapolations to small halo masses. We use a variety of observations to further constrain the characteristics of the galaxy populations, including the escape fraction of UV photons. Our approach provides an empirically-calibrated, physically-motivated model for the properties of star-forming galaxies sourcing the epoch of reionization. In the case where star formation in low-mass halos is maximally efficient, an average escape fraction ∼ 0.1 can reproduce the optical depth reported by Planck, whereas inefficient star formation in these halos requires either about twice as many UV photons to escape, or an escape fraction that increases towards higher redshifts. Our models also predict how future observations with JWST can improve our understanding of these galaxy populations.

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Section: Other Reionization Constraintssupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Constraints on the star formation efficiency of galaxies during the epoch of reionization

Sun

Furlanetto

2016

Mon. Not. R. Astron. Soc.

183

157

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“…Qualitatively, the non-negligible neutral fraction predicted by our model at z ∼ > 7 is consistent with the observed high optical depth of Lyα (Ouchi et al 2010;Treu et al 2013;Pentericci et al 2014;Schenker et al 2014;Tilvi et al 2014;Faisst et al 2014, K. B. Schmidt et al 2015, ApJ submitted), however the conversion from the Lyα emission fraction to the volume filling factor of ionized hydrogen is difficult and requires several assumptions . In particular, to make constraints on reionization it is generally assumed that there are no changes in galaxy and the Lyα emission line properties, which necessitates a rapid evolution of the global ionization fraction between z ∼ 6 and z ∼ 7.…”

Section: Q(z)supporting

confidence: 85%

“…We plot our results from integrating the model UV LFs to two magnitude limits of Mab = −17 (green) and Mab = −12 (purple), with 1σ confidence regions as shaded regions. We also plot constraints derived from observations of: Lyα emission from galaxies (open circles, Ouchi et al 2010;Pentericci et al 2014;Tilvi et al 2014;Faisst et al 2014;Schenker et al 2014); the Lyα forest (filled circles, Fan et al 2006); the clustering of Lyα emitting galaxies (square, Ouchi et al 2010); GRB spectra damping wings (diamond, McQuinn et al 2008); dark gaps in the Lyα forest (upper triangles, McGreer et al 2015); quasar near zones (star, Venemans et al 2015); and quasar spectra damping wings (lower triangle, Schroeder et al 2013). We also plot the Planck Collaboration et al (2015) redshift of instantaneous reionization.…”

Section: Q(z)mentioning

confidence: 99%

The Galaxy UV Luminosity Function Before the Epoch of Reionization

Mason

Trenti²,

Treu

2015

Proc. IAU

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We present a model for the evolution of the galaxy ultraviolet (UV) luminosity function (LF) across cosmic time where star formation is linked to the assembly of dark matter halos under the assumption of a mass dependent, but redshift independent, efficiency. We introduce a new self-consistent treatment of the halo star formation history, which allows us to make predictions at z > 10 (lookback time ∼ < 500 Myr), when growth is rapid. With a calibration at a single redshift to set the stellar-to-halo mass ratio, and no further degrees of freedom, our model captures the evolution of the UV LF over all available observations (0 ∼ < z ∼ < 10). The significant drop in luminosity density of currently detectable galaxies beyond z ∼ 8 is explained by a shift of star formation toward less massive, fainter galaxies. Assuming that star formation proceeds down to atomic cooling halos, we derive a reionization optical depth τ = 0.056 +0.007 −0.010 , fully consistent with the latest Planck measurement, implying that the universe is fully reionized at z = 7.84 +0.65 −0.98 . In addition, our model naturally produces smoothly rising star formation histories for galaxies with L ∼ < L * in agreement with observations and hydrodynamical simulations. Before the epoch of reionization at z > 10 we predict the LF to remain well-described by a Schechter function, but with an increasingly steep faint-end slope (α ∼ −3.5 at z ∼ 16). Finally, we construct forecasts for surveys with JWST and WFIRST and predict that galaxies out to z ∼ 14 will be observed. Galaxies at z > 15 will likely be accessible to JWST and WFIRST only through the assistance of strong lensing magnification.

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“…Stark et al 2010Stark et al , 2011Fontana et al 2010;Pentericci et al 2011;Caruana et al 2014;Faisst et al 2014;Schenker et al 2014;Tilvi et al 2014). However, this interpretation is complicated by caveats including the redshift dependence of the relative effects of dust on Lyα and ultraviolet (UV) continuum photons (Dayal & Ferrara 2012) and the fact that simple cuts in EW and UV luminosity may lead to uncertainties in the LAE number densities (Dijkstra & Wyithe 2012).…”

Section: Introductionmentioning

confidence: 99%

Clustering and lifetime of Lyman Alpha Emitters in the Epoch of Reionization

Hutter

Dayal

Müller

2015

Monthly Notices of the Royal Astronomical Society

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We calculate Lyman Alpha Emitter (LAE) angular correlation functions (ACFs) at z 6.6 and the fraction of lifetime (for the 100 Myrs preceding z 6.6) galaxies spend as Lyman Break Galaxies (LBGs) or as LBGs with Lyman Alpha (Lyα) emission using a model that combines SPH cosmological simulations (GADGET-2), dust attenuation and a radiative transfer code (pCRASH). The ACFs are a powerful tool that significantly narrows the 3D parameter space allowed by LAE Lyα and UV luminosity functions (LFs) alone. With this work, we simultaneously constrain the escape fraction of ionizing photons f esc = 0.05 − 0.5, the mean fraction of neutral hydrogen in the intergalactic medium (IGM) χ HI < ∼ 0.01 and the dust-dependent ratio of the escape fractions of Lyα and UV continuum photons f α /f c = 0.6 − 1.2. Our results show that reionization has the largest impact on the amplitude of the ACFs, and its imprints are clearly distinguishable from those of f esc and f α /f c . We also show that galaxies with a critical stellar mass of M * = 10 8.5 (10 9.5 )M produce enough luminosity to stay visible as LBGs (LAEs). Finally, the fraction of time during the past 100 Myrs prior to z = 6.6 a galaxy spends as a LBG or as a LBG with Lyα emission increases with the UV magnitude (and the stellar mass M * ): considering observed (dust and IGM attenuated) luminosities, the fraction of time a galaxy spends as a LBG (LAE) increases from 65% to 100% ( 0 − 100%) as M U V decreases from M U V = −18.0 to −23.5 (M * increases from 10 8 − 10 10.5 M ). Thus in our model the brightest (most massive) LBGs most often show Lyα emission.

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RAPID DECLINE OF Lyα EMISSION TOWARD THE REIONIZATION ERA

Cited by 200 publications

References 74 publications

Constraints on the star formation efficiency of galaxies during the epoch of reionization

Constraints on the star formation efficiency of galaxies during the epoch of reionization

The Galaxy UV Luminosity Function Before the Epoch of Reionization

Clustering and lifetime of Lyman Alpha Emitters in the Epoch of Reionization

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