First light and reionization: A conference summary

Barton, Elizabeth J.; Bullock, James S.; Cooray, Asantha; Kaplinghat, Manoj

doi:10.1016/j.newar.2005.11.024

Cited by 3 publications

(3 citation statements)

References 69 publications

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“…On the other hand, a fit of the observed LF with f 912 HI ≈ 0 and ignoring dust attenuation yields a conservative lower limit of f Lyα IGM 0.1 − 0.4 at z ≈ 6.5 (see Dijkstra, Wyithe & Haiman 2007). Figure 7 also shows our predictions for the LAE LF at z ≈ 8, when the Lyα line lies in the J band (see Barton et al 2006), assuming f Lyα IGM ≈ 0.5. However, if indeed the reionization is due to LBGs, we expect that the IGM ionization level can be significantly lower at this redshift, and the dimming of the Lyα luminosity substantially stronger.…”

Section: The Interstellar Dust Attenuates L Intmentioning

confidence: 90%

The Role of the Dust in Primeval Galaxies: A Simple Physical Model for Lyman Break Galaxies and Lyα Emitters

Mao

Lapi

Granato

et al. 2007

ApJ

101

134

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We explore the onset of star formation in the early universe, exploiting the observations of high-redshift LBGs and Ly emitters (LAEs), in the framework of the galaxy formation scenario elaborated by Granato and coworkers, already successfully tested against the wealth of data on later evolutionary stages. Complementing the model with a simple, physically plausible recipe for the evolution of dust attenuation in metal-poor galaxies, we reproduce the LFs of LBGs and of LAEs at different redshifts. This recipe yields a much faster increase with galactic age of attenuation in more massive galaxies, endowed with higher SFRs. These objects have therefore shorter lifetimes in the LAE and LBG phases and are more easily detected in the dusty submillimeter-bright (SMB) phase. The short UV-bright lifetimes of massive objects strongly mitigate the effect of the fast increase of the massive halo density with decreasing redshift, thus accounting for the weaker evolution of the LBG LF, compared to that of the halo mass function, and the even weaker evolution between z % 6 and z % 3 of the LAE LF. The much lower fraction of LBGs hosting detectable nuclear activity, compared to SMB galaxies, comes out naturally from the evolutionary sequence yielded by the model, which features the coevolution of galaxies and active nuclei. In this framework LAEs are on the average expected to be younger, with lower stellar masses, more compact, and associated with less massive halos than LBGs. Finally, we show that the IGM can be completely reionized at redshift z % 6Y7 by massive stars shining in protogalactic spheroids with halo masses from a few times 10 10 to a few times 10 11 M , showing up as faint LBGs with magnitude in the range À17 P M 1350 P À20, without resorting to any special stellar IMF.

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Section: The Interstellar Dust Attenuates L Intmentioning

confidence: 90%

The Role of the Dust in Primeval Galaxies: A Simple Physical Model for Lyman Break Galaxies and Lyα Emitters

Mao

Lapi

Granato

et al. 2007

ApJ

101

134

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“…Such studies have been limited to a redshift range of z<6.6. New attempts are in progress [9][10][11][12] to search for galaxy populations at 7<z<10, using deep narrowband imaging observations with near-infrared cameras, aiming for high sensitivity despite the limited survey volume. We have taken another approach to survey z=7 LAEs, specifically using the last OH window accessible with a wide-field charge-coupled device (CCD) camera.…”

Section: (Refs 4-8)mentioning

confidence: 99%

A galaxy at a redshift z = 6.96

Iye

Ota

Kashikawa

et al. 2006

Nature

338

441

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When galaxy formation started in the history of the Universe remains unclear. Studies of the cosmic microwave background indicate that the Universe, after initial cooling (following the Big Bang), was reheated and reionized by hot stars in newborn galaxies at a redshift in the range 6 < z < 14 (ref. 1). Though several candidate galaxies at redshift z > 7 have been identified photometrically, galaxies with spectroscopically confirmed redshifts have been confined to z < 6.6 (refs 4-8). Here we report a spectroscopic redshift of z = 6.96 (corresponding to just 750 Myr after the Big Bang) for a galaxy whose spectrum clearly shows Lyman-alpha emission at 9,682 A, indicating active star formation at a rate of approximately 10M(o) yr(-1), where M(o) is the mass of the Sun. This demonstrates that galaxy formation was under way when the Universe was only approximately 6 per cent of its present age. The number density of galaxies at z approximately 7 seems to be only 18-36 per cent of the density at z = 6.6.

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“…Reionization marks the historical event when hydrogen in the universe transformed from mostly neutral to mostly ionized; it has only recently become accessible via observations and numerical simulations and has stirred great interest and advances in our understanding of early structure formation (see e.g. reviews by Barkana & Loeb 2001; Loeb & Barkana 2001; Barton et al 2006; Loeb 2006).…”

Section: Introductionmentioning

confidence: 99%

Source mergers and bubble growth during reionization

Cohn

Chang

2007

Monthly Notices of the Royal Astronomical Society

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The recently introduced models of reionization bubbles based on extended Press–Schechter theory (by Furlanetto, Hernquist & Zaldarriaga) are generalized to include mergers of ionization sources. Sources with a recent major merger are taken to have enhanced photon production due to star formation, and accretion on to a central black hole if a black hole is present. This produces a scatter in the number of ionized photons corresponding to a halo of a given mass and a change in photon production over time for any given halo mass. By extending previous methods, photon production histories, bubble distributions and ionization histories are computed for several different parameter and recombination assumptions. The resulting distributions interpolate between previously calculated limiting cases.

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First light and reionization: A conference summary

Cited by 3 publications

References 69 publications

The Role of the Dust in Primeval Galaxies: A Simple Physical Model for Lyman Break Galaxies and Lyα Emitters

The Role of the Dust in Primeval Galaxies: A Simple Physical Model for Lyman Break Galaxies and Lyα Emitters

A galaxy at a redshift z = 6.96

Source mergers and bubble growth during reionization

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