Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 2606.06963

From Cosmic Web to Supernova Remnants: Modeling FRB DM to Trace Baryons across Multiple Scales

Zhao Joseph Zhang
View original source ↗Read source document ↗Export metadata ↓

Abstract

Fast radio bursts (FRBs) provide a powerful probe of ionized baryons through their dispersion measures (DMs), but the observed signal contains contributions from the intergalactic medium (IGM), circumgalactic (CGM) gas, host galaxies, and source-local environments. In this thesis, I investigate FRB DMs from cosmic-web to source-local scales using cosmological simulations, zoom-in galaxy simulations, and supernova-remnant (SNR) simulations. Using the CROCODILE simulation suite, I study the DM-$z$ relation, baryon distribution, halo contributions, and host-galaxy DMs. AGN feedback redistributes baryons from halo centers into the diffuse CGM/IGM gas, particularly affecting DM contributions from massive foreground halos. From the simulated DM-$z$ relation, I derive diffuse baryon fractions of $f_{\rm diff}=0.865^{+0.101}_{-0.165}$ and $0.856^{+0.101}_{-0.162}$ for the fiducial and NoBH models. Host-galaxy DM contributions range from below 100 pc cm$^{-3}$ in dwarf galaxies to above 1300 pc cm$^{-3}$ in cluster environments. I also model young magnetars embedded in SNRs using one-dimensional hydrodynamical simulations. The dominant time-variable DM component arises from unshocked ejecta, while the shocked region contributes only a minor fraction. Comparisons with FRB 20190520B and FRB 20121102 suggest source-local DM contributions of tens to hundreds of pc cm$^{-3}$. Most models become transparent to GHz radio emission within 70 yr. In contrast, the shocked region dominates the RM contribution and evolution, with the $11\,M_\odot$ single-star model best reproducing the RM evolution of FRB 20121102. These results demonstrate that FRB dispersion measures must be interpreted as multi-component signals spanning a wide range of physical scales, linking the cosmic web, gaseous halos, host galaxies, and compact-object environments

Explore related subjects

astro-ph.CO

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Zhao Joseph Zhang. 2026-06-05. From Cosmic Web to Supernova Remnants: Modeling FRB DM to Trace Baryons across Multiple Scales. https://arxiv.org/abs/2606.06963

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Absorption effects in the expanding Universe: spectral transmittance functions of the intergalactic medium for distant sources

We construct two self-consistent analytic approximations to the neutral hydrogen fraction, $x_{\rm HI}(z)$, and the helium ionization fractions, $x_{\rm HeI}(z)$, $x_{\rm HeII}(z)$, and $x_{\rm HeIII}(z)$, that are consistent with current constraints inferred from quasar spectra, galaxy surveys, and CMB polarization measurements. These approximations describe observationally motivated early- and late-reionization scenarios. Using these histories, we analyse the formation of broad absorption troughs in the continuum spectra of high-redshift sources over $1\leq z_{\rm s}\leq15$. We assume that neutral hydrogen and helium in a homogeneous diffuse intergalactic medium reside predominantly in their ground states and absorb radiation through the Lyman-series lines and continua of HI, HeI, and HeII. We compute the wavelength-dependent optical depths for the first 39 Lyman-series lines of HI and HeII, the first 10 lines of HeI, and the corresponding continua, and use them to derive spectral transmittance functions, $T(λ;z_{\rm s})$. As illustrative applications, we apply them to toy-model continuum spectra of starless haloes and to model spectra of a low-metallicity dwarf galaxy at different redshifts. Spectral features in sources at $5\lesssim z_{\rm s}\lesssim7$ caused by intergalactic absorption are found to be particularly sensitive to the adopted hydrogen and helium ionization histories

astro-ph.CO↗
arXiv2026

Union3.1: Reducing Systematics in Supernova Cosmology with Self-consistent Measurements of Host Galaxy Properties for 2000 Type Ia Supernovae

Photometrically derived distances of Type Ia supernovae (SNe Ia) rely on a $\sim5\%$ empirical correction based on host galaxy properties, e.g., global stellar mass. Unbiased cosmology inference therefore requires the self-consistent determination of host properties across the full range of redshifts probed, which we undertake here for approximately 2000 SNe in the Union3 compilation (now Union3.1). We use homogeneous, optical-infrared photometry from the DESI Legacy Imaging Surveys to infer global galaxy properties using the stellar population synthesis and SED-fitting code Prospector. We find that the host masses of $z<0.1$ SNe in Union3 were on average overestimated, while the opposite was true for $z<0.15$ SNe in Pantheon+. After correction, the two studies' average distance modulus estimated for low-redshift SNe, previously $>0.03$ mag discrepant, come into 0.01 mag agreement. Updating the UNITY SN analysis, we find the uncertainties on all standardization parameters shrink to $0.6$-$0.9\times$ their previous sizes. For flat-$Λ$CDM, we find from SNe alone $Ω_m=0.344^{+0.026}_{-0.025}$ (a $-0.4σ$ shift from Union3). We then combine with measurements of Baryon Acoustic Oscillations and the Cosmic Microwave Background exactly as done by DESI DR2 and find for flat $w_0w_a$CDM, $w_0=-0.719\pm0.084$ and $w_a=-0.95^{+0.29}_{-0.26}$, corresponding to $3.4σ$ evidence against a cosmological constant (down from $3.8σ$ per DESI-DR2+Planck+Union3). Updating the DESI-DR2+Planck+SN combined probe analysis with the recent Dovekie recalibration of DES-SN5YR (B. Popovic et al. 2025) or the updated Pantheon+, we find $3.4σ$ (was $4.2σ$ before Dovekie) and $3.2σ$ (was $2.8σ$ before our correction to Pantheon+) evidence, respectively, against a cosmological constant--a significantly improved consistency between SN analyses.

astro-ph.CO↗
arXiv2026

Reconciling large-scale Lyman-$α$ correlations with the SCRIPT Semi-numerical Model

Recent analyses of high-redshift Lyman-$α$ forest observations have revealed strong correlations on scales exceeding 200 cMpc at redshift z = 6. Reproducing these large-scale correlations has proven challenging for current large-volume reionization simulations. In this work, we investigate these large-scale correlations using mock spectra generated from the extended SCRIPT semi-numerical reionization model. We find that while the fiducial model ensemble systematically predicts smaller correlation lengths than those inferred from the 67 sightlines in the extended XQR-30 sample, 17.5% of individual mock realizations can naturally reproduce the observed signal. Using a delete-2 jackknife analysis, we demonstrate that the observed large-scale correlation length is disproportionately driven by a rare pair of highly transmissive sightlines associated with high-redshift transmission spikes. By inserting two such highly transmissive sightlines into our mock realizations, the fraction of realizations consistent with the observed redshift evolution and correlation length increases significantly from 17.5% to 74.1%. Furthermore, we show that spatial fluctuations in the ionizing mean free path remain an essential physical ingredient for reproducing the observed correlation structure. Our results suggest that the unexpectedly large Lyman-$α$ correlations can be reconciled with existing reionization models when accounting for cosmic variance and the outsized statistical impact of highly transmissive sightlines that occur as prominent outliers within the observational sample.

astro-ph.CO↗