Introducing SPHINX-MHD: the impact of primordial magnetic fields on the first galaxies, reionization, and the global 21-cm signal

We present the first results from SPHINX-MHD, a suite of cosmological radiation-magnetohydrodynamics simulations designed to study impact primordial magnetic fields (PMFs) on galaxy formation and evolution intergalactic medium during epoch reionization. The are among employ multi-frequency, on-the-fly radiation transfer constrained transport ideal MHD in context simultaneously model inhomogeneous process reionization as well growth PMFs. run series $(5\,\text{cMpc})^3$ volumes, varying both strength seed field ($B_0$) its spectral index ($n_B$). find that PMFs have $n_B > -0.562\log_{10}\left(\frac{B_0}{1{\rm n}G}\right) - 3.35$ produce electron optical depths ($\tau_e$) inconsistent with CMB constraints due unrealistically early collapse low-mass dwarf galaxies. For $n_B\geq-2.9$, our considerably tighter than $\sim{\rm n}G$ Planck. do not satisfy little history or shape UV luminosity function. Likewise, detecting changes Lya forest will be challenging because photoionisation photoheating efficiently smooth density field. However, we absorption feature global 21cm signal is sensitive indicator properties PMFs, even for those $\tau_e$ constraint. Furthermore, strong can marginally increase escape LyC photons by up 25\% shrink effective radii galaxies $\sim44\%$ which could completeness fraction surveys. Finally, show surveys magnitude limit ${\rm M_{UV,1500}=-13}$ probe sources provide majority out $z=12$.