I can see your halo: Constraining the Milky Way halo DM with FRB population studies

Fuente: arXiv
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Main Authors: Hoffmann, Jordan, James, Clancy, Prochaska, Jason Xavier, Glowacki, Marcin
Format: Preprint
Published: 2026
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author Hoffmann, Jordan
James, Clancy
Prochaska, Jason Xavier
Glowacki, Marcin
author_facet Hoffmann, Jordan
James, Clancy
Prochaska, Jason Xavier
Glowacki, Marcin
contents Fast radio bursts (FRBs) probe the electron column density along the line of sight and hence can be used to probe foreground structures. One such structure is the Galactic halo. In this work, we use a total of 98 high Galactic latitude ($|b| > 20^\circ$) FRBs detected by ASKAP, Parkes, DSA and FAST with 32 associated redshifts to constrain the dispersion measure (DM) contribution from the Galactic halo. We simultaneously fit unknown FRB population parameters, which show correlations with the Galactic halo but are not completely degenerate. We primarily use an isotropic model for the halo, but find no evidence favouring a particular halo model. We find DM$_{\rm MW,halo}$=$68^{+27}_{-24}$pc/cm$^3$, which is in agreement with other results within the literature. Previous constraints on DM$_{\rm MW,halo}$ with FRBs have used a few, low-DM FRBs. However, this is highly subject to fluctuations between different lines of sight, and hence using a larger number of sightlines as we do is more likely to be representative of the true average contribution. Nevertheless, we show that individual FRBs can still skew the data significantly and hence will be important in the future for more precise results.
format Preprint
id arxiv_https___arxiv_org_abs_2601_05496
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle I can see your halo: Constraining the Milky Way halo DM with FRB population studies
Hoffmann, Jordan
James, Clancy
Prochaska, Jason Xavier
Glowacki, Marcin
Astrophysics of Galaxies
Cosmology and Nongalactic Astrophysics
Fast radio bursts (FRBs) probe the electron column density along the line of sight and hence can be used to probe foreground structures. One such structure is the Galactic halo. In this work, we use a total of 98 high Galactic latitude ($|b| > 20^\circ$) FRBs detected by ASKAP, Parkes, DSA and FAST with 32 associated redshifts to constrain the dispersion measure (DM) contribution from the Galactic halo. We simultaneously fit unknown FRB population parameters, which show correlations with the Galactic halo but are not completely degenerate. We primarily use an isotropic model for the halo, but find no evidence favouring a particular halo model. We find DM$_{\rm MW,halo}$=$68^{+27}_{-24}$pc/cm$^3$, which is in agreement with other results within the literature. Previous constraints on DM$_{\rm MW,halo}$ with FRBs have used a few, low-DM FRBs. However, this is highly subject to fluctuations between different lines of sight, and hence using a larger number of sightlines as we do is more likely to be representative of the true average contribution. Nevertheless, we show that individual FRBs can still skew the data significantly and hence will be important in the future for more precise results.
title I can see your halo: Constraining the Milky Way halo DM with FRB population studies
topic Astrophysics of Galaxies
Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2601.05496