Title: | Binary pulsars as probes of a Galactic dark matter disk |
Author: |
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Date: | 2018-03 |
Language: | English |
Scope: | 1-11 |
University/Institute: | Háskóli Íslands University of Iceland |
School: | School of Engineering and Natural Sciences (UI) Verkfræði- og náttúruvísindasvið (HÍ) |
Department: | Raunvísindastofnun (HÍ) Science Institute (UI) |
Series: | Physics of the Dark Universe;19 |
ISSN: | 2212-6864 |
DOI: | 10.1016/j.dark.2017.10.005 |
Subject: | Dark disk; Binary pulsar; Stjörnufræði; Stjarneðlisfræði |
URI: | https://hdl.handle.net/20.500.11815/679 |
Citation:Caputo, A., Zavala, J., & Blas, D. (2018). Binary pulsars as probes of a Galactic dark matter disk. Physics of the Dark Universe, 19, 1-11. doi:https://doi.org/10.1016/j.dark.2017.10.005
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Abstract:As a binary pulsar moves through a wind of dark matter particles, the resulting dynamical friction modifies
the binary’s orbit. We study this effect for the double disk dark matter (DDDM) scenario, where a fraction
of the dark matter is dissipative and settles into a thin disk. For binaries within the dark disk, this effect
is enhanced due to the higher dark matter density and lower velocity dispersion of the dark disk, and
due to its co-rotation with the baryonic disk. We estimate the effect and compare it with observations for
two different limits in the Knudsen number (Kn). First, in the case where DDDM is effectively collisionless
within the characteristic scale of the binary (Kn ≫ 1) and ignoring the possible interaction between the
pair of dark matter wakes. Second, in the fully collisional case (Kn ≪ 1), where a fluid description can
be adopted and the interaction of the pair of wakes is taken into account. We find that the change in the
orbital period is of the same order of magnitude in both limits. A comparison with observations reveals
good prospects to probe currently allowed DDDM models with timing data from binary pulsars in the
near future. We finally comment on the possibility of extending the analysis to the intermediate (rarefied
gas) case with Kn ∼ 1.
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Rights:This is an open access article under the CC BY-NC-ND
license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
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