Search for: All records

We use FIRE-2 zoom simulations of Milky Way size disk galaxies to derive easy-to-use relationships between the observed circular speed of the Galaxy at the Solar location,v_c, and dark matter properties of relevance for direct detection experiments: the dark matter density, the dark matter velocity dispersion, and the speed distribution of dark matter particles near the Solar location. We find that both the local dark matter density and 3D velocity dispersion follow tight power laws withv_c. Using this relation together with the observed circular speed of the Milky Way at the Solar radius, we infer the local dark matter density and velocity dispersion near the Sun to beρ= 0.42±0.06 GeV cm^-3and^σ_3D= 280⁺¹⁹_-18km s^-1. We also find that the distribution of dark matter particle speeds is well-described by a modified Maxwellian with two shape parameters, both of which correlate with the observedv_c. We use that modified Maxwellian to predict the speed distribution of dark matter near the Sun and find that it peaks at a most probable speed of 257 km s^-1and begins to truncate sharply above 470 km s^-1. This peak speed is somewhat higher than expected from the standard halo model, and the truncation occurs well below the formal escape speed to infinity, with fewer very-high-speed particles than assumed in the standard halo model. 

Making sense of what to do about the many daunting socio-environmental issues that we face will require intercultural understanding, openness to learning, and a capacity to draw on the strengths of multiple perspectives and to recognize limitations of dominant perspectives such as Eurocentric science. Navigating multiple perspectives in the school science classroom can be particularly treacherous for Indigenous students, whose cultural worldviews have often been excluded or denigrated in Eurocentric educational contexts. We present findings from a partnership project that is designing, implementing, studying, and refining instructional experiences for middle school students from significantly/predominantly Indigenous communities in Alaska and Hawai’i. This paper describes our efforts to understand project partners’ standpoints, acknowledging that in designing and implementing multi-perspective middle school science instruction, it will be critical to understand the multiple perspectives that we ourselves bring to the work. We present and discuss the views that project partners (including teachers) have shared concerning science, science education, multiple perspectives, and Indigenous cultural integrity and potential consequentiality for the project’s collaborative work. Five prominent themes relate to (1) the challenge of defining Indigenous and Eurocentric science for application in an instructional design context, (2) relationships with place, (3) centrality of language, (4) scaffolding and understanding learning through a multi-perspective lens, and (5) constraints associated with Eurocentric classroom and science contexts.