Heating the Intergalactic Medium by X-Rays From Population Iii Binaries in High-Redshift Galaxies

Xu, Hao; Ahn, Kyungjin; Wise, John H.; Norman, Michael L.; O’Shea, Brian W.

doi:10.1088/0004-637x/791/2/110

Cited by 69 publications

(71 citation statements)

References 114 publications

(169 reference statements)

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“…Many details of the physical implementation of the implementation of the physics and also sub-grid recipes are provided in Xu et al (2013Xu et al ( , 2014 and Chen et al (2014). In the "Renaissance" simulations, flattening in the UV LF is a direct result of the Figure 13.…”

Section: Comparison With Theoretical Expectationsmentioning

confidence: 99%

The z ∼ 6 Luminosity Function Fainter than −15 mag from the Hubble Frontier Fields: The Impact of Magnification Uncertainties

Bouwens

Oesch

Illingworth

et al. 2017

ApJ

286

428

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We use the largest sample of z 6 galaxies to date from the first four Hubble Frontier Fields clusters to set constraints on the shape of the z 6 luminosity functions (LFs) to fainter than M 14 AB UV, = -mag. We quantify, for the first time, the impact of magnification uncertainties on LF results and thus provide more realistic constraints than other recent work. Our simulations reveal that, for the highly magnified sources, the systematic uncertainties can become extremely large fainter than −14 mag, reaching several orders of magnitude at 95% confidence at approximately−12 mag. Our new forward-modeling formalism incorporates the impact of magnification uncertainties into the LF results by exploiting the availability of many independent magnification models for the same cluster. One public magnification model is used to construct a mock high-redshift galaxy sample that is then analyzed using the other magnification models to construct an LF. Large systematic errors occur at high magnifications ( 30  m ) because of differences between the models. The volume densities we derive for faint (−17 mag) sources are ∼3-4× lower than one recent report and give a faint-end slope 1.92 0.04 a = - , which is 3.0-3.5σ shallower (including or not including the size uncertainties, respectively). We introduce a new curvature parameter δ to model the faint end of the LF and demonstrate that the observations permit (at 68% confidence) a turn-over at z 6 in the range of −15.3 to −14.2 mag, depending on the assumed lensing model. The present consideration of magnification errors and new size determinations raise doubts about previous reports regarding the form of the LF at 14 mag >-. We discuss the implications of our turn-over constraints in the context of recent theoretical predictions.

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Section: Comparison With Theoretical Expectationsmentioning

confidence: 99%

The z ∼ 6 Luminosity Function Fainter than −15 mag from the Hubble Frontier Fields: The Impact of Magnification Uncertainties

Bouwens

Oesch

Illingworth

et al. 2017

ApJ

286

428

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“…We allowed further local refinement (and then, the star formation) in the Lagrangian volume of the finest nested grid based on baryon or dark matter overdensity for up to 12 total levels of refinement (i.e., a comoving resolution of 19 pc in the finest cells.) For more details about the calculations and scientific results about Renaissance Simulations, see Xu et al (2013Xu et al ( , 2014; Chen et al (2014); O'Shea et al (2015).…”

Section: The Renaissance Simulations and X-ray Modelsmentioning

confidence: 99%

“…We do this in two different ways. In Method 1, we adopt the same simple prescription described in Xu et al (2014); namely for every root grid cell in the refinement volume containing X-ray emitting sources, we sum up their baryon density ρ and X-ray luminosity L. Dividing by the number of emitting cells we have their average values ρ andL. Then, in the unrefined portion of the simulation volume, if the root grid cell's baryon density ρ ≥ρ, we assign it an X-ray luminosityL.…”

Section: The Renaissance Simulations and X-ray Modelsmentioning

confidence: 99%

“…X-rays from Pop III binaries have been suggested to produce a pre-heated IGM (e.g., Mirabel et al 2011;Haiman 2011;Visbal et al 2012;Mesinger et al 2013;Madau & Fragos 2016), and to partially ionize the IGM in large volumes (e.g., Ostriker & Gnedin 1996;Pritchard & Furlanetto 2007). Xu et al (2014) showed that Pop III binaries might be the dominant X-ray sources at high redshifts and discussed how the IGM might be heated locally by hundred eV photons and globally by the X-ray background from keV photons. Homogeneously heating of the IGM on tens to hundreds Mpc scales by an X-ray background may be important to understand the linewidths of Lyα forest spectra (Tytler et al 2009) and high-z 21-cm neutral hydrogen line signatures (Ahn et al 2015).…”

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confidence: 99%

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X-Ray Background at High Redshifts From Pop Iii Remnants: Results From Pop Iii Star Formation Rates in the Renaissance Simulations

Ahn

Norman

et al. 2016

ApJ

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Due to their long mean free paths, X-rays are expected to have global impacts on the properties of the intergalactic medium (IGM) by their large scale heating and ionizing processes. At high redshifts, X-rays from Population (Pop) III binaries might have important effects on cosmic reionization and the Lyα forest. As a continuation of our previous work on Pop III binary X-rays , we use the Pop III distribution and evolution from the Renaissance Simulations, a suite of self-consistent cosmological radiation hydrodynamics simulations of the formation of the first galaxies, to calculate the X-ray luminosity density and background over the redshift range 20 ≥ z ≥ 7.6. As we find that Pop III star formation continues at a low, nearly constant rate to the end of reionization, X-rays are being continuously produced at significant rates compared to other possible X-ray sources, such as AGNs and normal X-ray binaries during the same period of time. We estimate that Pop III binaries produce approximately 6 eV of energy in the X-rays per hydrogen atom. We calculate the X-ray background for different monochromatic photon energies. KeV X-rays redshift and accumulate to produce a strong X-ray background spectrum extending to roughly 500 eV. The X-ray background is strong enough to heat the IGM to ∼ 1000 K and to ionize a few percent of the neutral hydrogen. These effects are important for an understanding of the neutral hydrogen hyperfine transition 21-cm line signatures, the Lyα forest, and the Thomson optical depth to the CMB.

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“…Fewer ionizing photons are then needed to keep the gas ionized, which facilitates reionization (e.g., Pawlik, Schaye, & van Scherpenzeel 2009;Shull et al 2012;Finlator et al 2012;Sobacchi & Mesinger 2014). This positive feedback from photoheating will be especially strong if X-ray sources preheat the gas before it is reionized (e.g., Madau et al 2004;Ricotti, Ostriker, & Gnedin 2005;Haiman 2011;Jeon et al 2014a;Xu et al 2014;Knevitt et al 2014). …”

Section: Introductionmentioning

confidence: 99%

Spatially adaptive radiation-hydrodynamical simulations of galaxy formation during cosmological reionization

Pawlik

Schaye

Vecchia

2015

Monthly Notices of the Royal Astronomical Society

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We present a suite of cosmological radiation-hydrodynamical simulations of the assembly of galaxies driving the reionization of the intergalactic medium (IGM) at z 6. The simulations account for the hydrodynamical feedback from photoionization heating and the explosion of massive stars as supernovae (SNe). Our reference simulation, which was carried out in a box of size 25 h −1 comoving Mpc using 2 × 512 3 particles, produces a reasonable reionization history and matches the observed UV luminosity function of galaxies. Simulations with different box sizes and resolutions are used to investigate numerical convergence, and simulations in which either SNe or photoionization heating or both are turned off, are used to investigate the role of feedback from star formation. Ionizing radiation is treated using accurate radiative transfer at the high spatially adaptive resolution at which the hydrodynamics is carried out. SN feedback strongly reduces the star formation rates (SFRs) over nearly the full mass range of simulated galaxies and is required to yield SFRs in agreement with observations. Photoheating helps to suppress star formation in low-mass galaxies, but its impact on the cosmic SFR is small. Because the effect of photoheating is masked by the strong SN feedback, it does not imprint a signature on the UV galaxy luminosity function, although we note that our resolution is insufficient to model star-forming minihaloes cooling through molecular hydrogen transitions. Photoheating does provide a strong positive feedback on reionization because it smooths density fluctuations in the IGM, which lowers the IGM recombination rate substantially. Our simulations demonstrate a tight non-linear coupling of galaxy formation and reionization, motivating the need for the accurate and simultaneous inclusion of photoheating and SN feedback in models of the early Universe.

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Heating the Intergalactic Medium by X-Rays From Population Iii Binaries in High-Redshift Galaxies

Cited by 69 publications

References 114 publications

The z ∼ 6 Luminosity Function Fainter than −15 mag from the Hubble Frontier Fields: The Impact of Magnification Uncertainties

The z ∼ 6 Luminosity Function Fainter than −15 mag from the Hubble Frontier Fields: The Impact of Magnification Uncertainties

X-Ray Background at High Redshifts From Pop Iii Remnants: Results From Pop Iii Star Formation Rates in the Renaissance Simulations

Spatially adaptive radiation-hydrodynamical simulations of galaxy formation during cosmological reionization

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