On the use of seminumerical simulations in predicting the 21-cm signal from the epoch of reionization

Majumdar, Suman; Mellema, Garrelt; Datta, Kanan K.; Jensen, Hannes; Choudhury, Tirthankar Roy; Bharadwaj, Somnath; Friedrich, Martina M.

doi:10.1093/mnras/stu1342

Cited by 103 publications

(119 citation statements)

References 80 publications

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“…The fact that ARTIST and InstESF are -at similar x HI values, although at very different redshifts -similar in power spectrum and topology, is in agreement with what found by Zahn et al (2011);Majumdar et al (2014) and Hutter (2018). While TimeIntESF has, in principle, a more physically-motivated ionisation condition, further improvements to the model are clearly required to obtain a topology consistent with the one predicted by the self-consistent RT calculation of ARTIST.…”

Section: Discussionsupporting

confidence: 83%

Artist: fast radiative transfer for large-scale simulations of the epoch of reionization

Molaro

Davé

Hassan

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We introduce the "Asymmetric Radiative Transfer In Shells Technique" (Artist), a new method for photon propagation on large scales that explicitly conserves photons, propagates photons at the speed of light, approximately accounts for photon directionality, and closely reproduces results of more detailed radiative transfer (RT) codes. Crucially, it is computationally fast enough to evolve the large cosmological volumes required to predict the 21cm power spectrum on scales that will be probed by future experiments targeting the Epoch of Reionisation (EoR). Most semi-numerical models aimed at predicting the EoR 21cm signal make use of an excursion set formalism (ESF) approach, which achieves computational viability by compromising on photon conservation, constraining ionised regions to be spherical by construction, and not accounting for light-travel time. By implementing our RT method within the semi-numerical code SimFast21, we show that Artist predicts a significantly different evolution for the EoR ionisation field compared to the code's native ESF. In particular, Artist predicts a more gradual evolution of the volume-averaged ionisation fraction, and up to an order-of-magnitude difference in the ionisation power, depending on the physical parameters assumed. Its application to large-scale EoR simulations will therefore allow more physically-motivated constraints to be obtained for key EoR parameters, such as the escape fraction. and moment-based methods, with different strengths and weaknesses, balancing accuracy versus computational efficiency (Trac & Gnedin 2011). Often, while these methods can be made optimally accurate with sufficient computational investment, they remain computationally prohibitive in large-scale cosmological simulations that seek to reproduce the evolution of the universe on at least tens of Mpc scales, while simultaneously ensuring that the injection and propagation of photons on the smallest scales is both accurate and self-consistent.One particular such case, currently at the forefront of astrophysical research, is the modelling of the last global phase-change in the history of the universe -the epoch of reionisation (EoR). The sources of the photons respon-

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Section: Discussionsupporting

confidence: 83%

Artist: fast radiative transfer for large-scale simulations of the epoch of reionization

Molaro

Davé

Hassan

et al. 2019

Monthly Notices of the Royal Astronomical Society

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“…The estimation of each multipole moment through Equation (5) will be independent of the other, as this representation is in an orthonormal basis. Under the quasi-linear model of Mao et al (2012), only the first three even multipole moments will have nonzero values (Majumdar, Bharadwaj & Choudhury 2013;Majumdar et al 2014):…”

Section: Quantifying the Power Spectrum Anisotropymentioning

confidence: 99%

Effects of the sources of reionization on 21-cm redshift-space distortions

Majumdar¹,

Jensen²,

Mellema³

et al. 2015

Mon. Not. R. Astron. Soc.

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The observed 21-cm signal from the epoch of reionization will be distorted along the line-of-sight by the peculiar velocities of matter particles. These redshift-space distortions will affect the contrast in the signal and will also make it anisotropic. This anisotropy contains information about the cross-correlation between the matter density field and the neutral hydrogen field, and could thus potentially be used to extract information about the sources of reionization. In this paper, we study a collection of simulated reionization scenarios assuming different models for the sources of reionization. We show that the 21-cm anisotropy is best measured by the quadrupole moment of the power spectrum. We find that, unless the properties of the reionization sources are extreme in some way, the quadrupole moment evolves very predictably as a function of global neutral fraction. This predictability implies that redshift-space distortions are not a very sensitive tool for distinguishing between reionization sources. However, the quadrupole moment can be used as a model-independent probe for constraining the reionization history. We show that such measurements can be done to some extent by first-generation instruments such as LOFAR, while the SKA should be able to measure the reionization history using the quadrupole moment of the power spectrum to great accuracy.

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“…There has been extensive theoretical work modelling both the 21-cm signal (including Beane & Lidz 2018;Shimabukuro & Semelin 2017;Kulkarni et al 2017;Hassan et al 2016;Kulkarni et al 2016;Mesinger et al 2011;McQuinn et al 2006) and the LAE population (including Laursen et al 2018;Inoue et al 2018;Weinberger et al 2019;Mason et al 2018;Kakiichi et al 2016;Hutter et al 2015;Gronke et al 2015;Hutter et al 2014;Zheng & Wallace 2014;Jensen et al 2013;Dijkstra et al 2007) during the epoch of reionization. The epoch of reionization has been explored with analytic prescriptions (such as Furlanetto et al 2004), using semi-numerical modelling (such as Mesinger et al 2011;Majumdar et al 2014), and full numerical simulation (such as Trac & Cen 2007;Rosdahl et al 2018;Chardin et al 2015). The challenge of modelling reionization is to try to capture the physical processes which occur on extremely different scales: from the largescale ionized bubble structure (McQuinn et al 2007a;Zahn et al 2007;Giri et al 2018), to the small-scale self-shielding of neutral gas clumps (Rahmati et al 2013;Chardin et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Probing delayed-end reionization histories with the 21-cm LAE cross-power spectrum

Weinberger

Kulkarni

Haehnelt

2020

Monthly Notices of the Royal Astronomical Society

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We model the 21-cm signal and LAE population evolution during the epoch of reionization in order to predict the 21cm-LAE cross-power spectrum. We employ highdynamic-range simulations of the IGM to create models that are consistent with constraints from the CMB, Lyman-α forest and LAE population statistics. Using these models we consider the evolution of the cross-power spectrum for a selection of realistic reionization histories and predict the sensitivity of current and upcoming surveys to measuring this signal. We find that the imprint of a delayed-end to reionization can be observed by future surveys, and that strong constraints can be placed on the progression of reionization as late as z = 5.7 using a Subaru-SKA survey. We make predictions for the signal-to-noise ratios achievable by combinations of Subaru/PFS with the MWA, LOFAR, HERA and SKA interferometers. We find that a Subaru-SKA survey could measure the cross-power spectrum for a late reionization at z = 6.6 with a total signal-to-noise greater than 5, making it possible to constrain both the timing and bubble size at the end of reionization. Furthermore, we find that expanding the current Subaru/PFS survey area and depth by a factor of three would double the total signal-to-noise.

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On the use of seminumerical simulations in predicting the 21-cm signal from the epoch of reionization

Cited by 103 publications

References 80 publications

Artist: fast radiative transfer for large-scale simulations of the epoch of reionization

Artist: fast radiative transfer for large-scale simulations of the epoch of reionization

Effects of the sources of reionization on 21-cm redshift-space distortions

Probing delayed-end reionization histories with the 21-cm LAE cross-power spectrum

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