The epoch of cosmic heating by early sources of X-rays

Eide, Marius B.; Graziani, Luca; Ciardi, B.; Feng, Yu; Kakiichi, Koki; Matteo, Tiziana Di

doi:10.1093/mnras/sty272

Cited by 71 publications

(67 citation statements)

References 125 publications

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“…The difference found between our work and that in Eide et al (2018) is model dependent and is in part due to their seeding algorithm only allowing the formation of black holes in haloes greater than 10 10 M , resulting in a much lower number density of QSOs. This lower density combined with the assumption that QSOs have optically thick, geometrically thin disks (as described in Shakura & Sunyaev (1973)) leads to a somewhat more conservative heating prediction than in our models.…”

Section: Discussionmentioning

confidence: 66%

Evaluating the QSO contribution to the 21-cm signal from the Cosmic Dawn

Ross

Dixon

Ghara

et al. 2019

Monthly Notices of the Royal Astronomical Society

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The upcoming radio interferometer Square Kilometre Array (SKA) is expected to directly detect the redshifted 21-cm signal from the neutral hydrogen present during the Cosmic Dawn. Temperature fluctuations from X-ray heating of the neutral intergalactic medium can dominate the fluctuations in the 21-cm signal from this time. This heating depends on the abundance, clustering, and properties of the X-ray sources present, which remain highly uncertain. We present a suite of three new large-volume, 349 Mpc a side, fully numerical radiative transfer simulations including QSO-like sources, extending the work previously presented in Ross et al. (2017). The results show that our QSOs have a modest contribution to the heating budget, yet significantly impact the 21-cm signal. Initially, the power spectrum is boosted on large scales by heating from the biased QSO-like sources, before decreasing on all scales. Fluctuations from images of the 21-cm signal with resolutions corresponding to SKA1-Low at the appropriate redshifts are well above the expected noise for deep integrations, indicating that imaging could be feasible for all the X-ray source models considered. The most notable contribution of the QSOs is a dramatic increase in non-Gaussianity of the signal, as measured by the skewness and kurtosis of the 21-cm probability distribution functions. However, in the case of late Lyman-α saturation, this non-Gaussianity could be dramatically decreased particularly when heating occurs earlier. We conclude that increased non-Gaussianity is a promising signature of rare X-ray sources at this time, provided that Lyman-α saturation occurs before heating dominates the 21-cm signal.

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Section: Discussionmentioning

confidence: 66%

Evaluating the QSO contribution to the 21-cm signal from the Cosmic Dawn

Ross

Dixon

Ghara

et al. 2019

Monthly Notices of the Royal Astronomical Society

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“…The heating and ionization rates per baryon inside the mostly neutral IGM are calculated with (see also, e.g. Baek & Ferrara 2013;Madau & Fragos 2017;Eide et al 2018)…”

Section: Corresponding Uv Luminosity Functionsmentioning

confidence: 99%

Inferring the astrophysics of reionization and cosmic dawn from galaxy luminosity functions and the 21-cm signal

Park

Mesinger

Greig

et al. 2019

Monthly Notices of the Royal Astronomical Society

244

279

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The properties of the first galaxies, expected to drive the Cosmic Dawn (CD) and the Epoch of Reionization (EoR), are encoded in the 3D structure of the cosmic 21-cm signal. Parameter inference from upcoming 21-cm observations promises to revolutionize our understanding of these unseen galaxies. However, prior inference was done using models with several simplifying assumptions. Here we introduce a flexible, physicallymotivated parametrization for high-z galaxy properties, implementing it in the public code 21cmfast. In particular, we allow their star formation rates and ionizing escape fraction to scale with the masses of their host dark matter halos, and directly compute inhomogeneous, sub-grid recombinations in the intergalactic medium. Combining current Hubble observations of the rest-frame UV luminosity function (UV LFs) at high-z with a mock 1000h 21-cm observation using the Hydrogen Epoch of Reionization Arrays (HERA), we constrain the parameters of our model using a Monte Carlo Markov Chain sampler of 3D simulations, 21cmmc. We show that the amplitude and scaling of the stellar mass with halo mass is strongly constrained by LF observations, while the remaining galaxy properties are constrained mainly by 21-cm observations. The two data sets compliment each other quite well, mitigating degeneracies intrinsic to each observation. All eight of our astrophysical parameters are able to be constrained at the level of ∼ 10% or better. The updated versions of 21cmfast and 21cmmc used in this work are publicly available.

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“…It is expected that X-rays, through their long mean free paths, are a dominant source of heat in the neutral IGM, outside of the HII regions which surround the nascent galaxies (e.g. Pritchard & Furlanetto 2007;McQuinn & O'Leary 2012;Mesinger et al 2013;Madau & Fragos 2017;Eide et al 2018). 21CMFAST computes the angle-averaged specific X-ray intensity (in units of erg s −1 keV −1 cm −2 sr −1 ) in each simulation cell at a given spatial position and redshift.…”

Section: Mock 21-cm Signalmentioning

confidence: 99%

Properties of reionization-era galaxies from JWST luminosity functions and 21-cm interferometry

Park

Gillet

Mesinger

et al. 2019

Monthly Notices of the Royal Astronomical Society

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Next generation observatories will enable us to study the first billion years of our Universe in unprecedented detail. Foremost among these are 21-cm interferometry with the Hydrogen Epoch of Reionization Arrays (HERA) and the Square Kilometre Array (SKA), and high-z galaxy observations with the James Webb Space Telescope (JWST). Taking a basic galaxy model, in which we allow the star formation rates and ionizing escape fractions to have a power-law dependence on halo mass with an exponential turnover below some threshold, we quantify how observations from these instruments can be used to constrain the astrophysics of high-z galaxies. For this purpose, we generate mock JWST LFs, based on two different hydrodynamical cosmological simulations; these have intrinsic luminosity functions (LFs) which turn over at different scales and yet are fully consistent with present-day observations. We also generate mock 21-cm power spectrum observations, using 1000h observations with SKA1 and a moderate foreground model. Using only JWST data, we predict up to a factor of 2-3 improvement (compared with HST) in the fractional uncertainty of the star formation rate to halo mass relation and the scales at which the LFs peak (i.e. turnover). Most parameters regulating the UV galaxy properties can be constrained at the level of ∼ 10% or better, if either (i) we are able to better characterize systematic lensing uncertainties than currently possible; or (ii) the intrinsic LFs peak at magnitudes brighter than M UV ∼ < −13. Otherwise, improvement over HST-based inference is modest. When combining with upcoming 21-cm observations, we are able to significantly mitigate degeneracies, and constrain all of our astrophysical parameters, even for our most pessimistic assumptions about upcoming JWST LFs. The 21-cm observations also result in an order of magnitude improvement in constraints on the EoR history.

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The epoch of cosmic heating by early sources of X-rays

Cited by 71 publications

References 125 publications

Evaluating the QSO contribution to the 21-cm signal from the Cosmic Dawn

Evaluating the QSO contribution to the 21-cm signal from the Cosmic Dawn

Inferring the astrophysics of reionization and cosmic dawn from galaxy luminosity functions and the 21-cm signal

Properties of reionization-era galaxies from JWST luminosity functions and 21-cm interferometry

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