Star Stream Velocity Distributions in CDM and WDM Galactic Halos
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| Main Authors: | , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866914913849442304 |
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| author | Carlberg, Raymond G. Jenkins, Adrian Frenk, Carlos S. Cooper, Andrew P. |
| author_facet | Carlberg, Raymond G. Jenkins, Adrian Frenk, Carlos S. Cooper, Andrew P. |
| contents | The dark matter subhalos orbiting in a galactic halo perturb the orbits of stars in thin stellar streams. Over time the random velocities in the streams develop non-Gaussian wings. The rate of velocity increase is approximately a random walk at a rate proportional to the number of subhalos, primarily those in the mass range $\approx 10^{6-7} M_\odot$. The distribution of random velocities in long, thin, streams is measured in simulated Milky Way-like halos that develop in representative WDM and CDM cosmologies. The radial velocity distributions are well modeled as the sum of a Gaussian and an exponential. The resulting MCMC fits find Gaussian cores of 1-2 km/sec and exponential wings that increase from 3 km/sec for 5.5 keV WDM, 4 km/sec for 7 keV WDM, to 6 km/sec for a CDM halo. The observational prospects to use stream measurements to constrain the nature of galactic dark matter are discussed. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2405_18522 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Star Stream Velocity Distributions in CDM and WDM Galactic Halos Carlberg, Raymond G. Jenkins, Adrian Frenk, Carlos S. Cooper, Andrew P. Astrophysics of Galaxies The dark matter subhalos orbiting in a galactic halo perturb the orbits of stars in thin stellar streams. Over time the random velocities in the streams develop non-Gaussian wings. The rate of velocity increase is approximately a random walk at a rate proportional to the number of subhalos, primarily those in the mass range $\approx 10^{6-7} M_\odot$. The distribution of random velocities in long, thin, streams is measured in simulated Milky Way-like halos that develop in representative WDM and CDM cosmologies. The radial velocity distributions are well modeled as the sum of a Gaussian and an exponential. The resulting MCMC fits find Gaussian cores of 1-2 km/sec and exponential wings that increase from 3 km/sec for 5.5 keV WDM, 4 km/sec for 7 keV WDM, to 6 km/sec for a CDM halo. The observational prospects to use stream measurements to constrain the nature of galactic dark matter are discussed. |
| title | Star Stream Velocity Distributions in CDM and WDM Galactic Halos |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2405.18522 |