Meiksin, A.; Khochfar, Sadegh; Paardekooper, Jan-Pieter; Dalla Vecchia, C.; Kohn, Saul
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 471, Issue 3, p.3632-3645
Advertised on:
11
2017
Citations
6
Refereed citations
6
Description
The diffuse soft X-ray emissivity from galactic winds is computed during
the Epoch of Reionization (EoR). We consider two analytic models, a
pressure-driven wind and a superbubble model, and a 3D cosmological
simulation including gas dynamics from the First Billion Years (FiBY)
project. The analytic models are normalized to match the diffuse X-ray
emissivity of star-forming galaxies in the nearby Universe. The
cosmological simulation uses physically motivated star formation and
wind prescriptions, and includes radiative transfer corrections. The
models and the simulation all are found to produce sufficient heating of
the intergalactic medium to be detectable by current and planned radio
facilities through 21 cm measurements during the EoR. While the analytic
models predict a 21 cm emission signal relative to the cosmic microwave
backgroundsets in by ztrans ≃ 8-10, the predicted signal
in the FiBY simulation remains in absorption until reionization
completes. The 21 cm absorption differential brightness temperature
reaches a minimum of ΔT ≃ -130 to -200 mK, depending on
model. Allowing for additional heat from high-mass X-ray binaries pushes
the transition to emission to ztrans ≃ 10-12, with
shallower absorption signatures having a minimum of ΔT ≃ -110
to -140 mK. The 21 cm signal may be a means of distinguishing between
the wind models, with the superbubble model favouring earlier reheating.
While an early transition to emission may indicate X-ray binaries
dominate the reheating, a transition to emission as early as
ztrans > 12 would suggest the presence of additional heat
sources.
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