Scaling relations for dark matter annihilation and decay profiles in dwarf spheroidal galaxies

Journal Article · Mon Oct 22 00:00:00 EDT 2018 · Monthly Notices of the Royal Astronomical Society

DOI:https://doi.org/10.1093/mnras/sty2839· OSTI ID:1630203

Pace, Andrew B.  ^[1]; Strigari, Louis E.  ^[1]

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1. George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A&M University, College Station, TX 77843, USA

Measuring the dark matter distribution in dwarf spheroidal galaxies (dSphs) from stellar kinematics is crucial for indirect dark matter searches, as these distributions set the fluxes for both dark matter annihilation (J-Factor) and decay (D-Factor). Here, we produce a compilation of J- and D-Factors for dSphs, including new calculations for several newly discovered Milky Way (MW) satellites, for dSphs outside of the MW virial radius, and for M31 satellites. From this compilation, we test for scaling relations between the J- and D-factors and physical properties of the dSphs such as the velocity dispersion ($$σ_{los}$$), the distance (d), and the stellar half-light radius ($$r_{1/2}$$). In this study, we find that the following scaling relation minimizes the residuals as compared to different functional dependences on the observed dSphs properties $$J$$(0$$ο\atop{.}$$5) = $$10^{17.87}$$ ($$σ_{los}$$/5 km $$s^{—1}$$)$$^4$ (d/100 kpc)$$^{—2}$$ $$(r_{1/2}$$/100 pc)$$^{—1}$$⁠. We find that this relation has considerably smaller scatter as compared to the simpler relations that scale only as 1/$d^2$. We further explore scalings with luminosity ($$L_V$$), and find that the data do not strongly prefer a scaling including $$L_V$$ as compared to a pure 1/$d^2$ scaling. The scaling relations we derive can be used to estimate the J-Factor without the full dynamical analysis, and will be useful for estimating limits on particle dark matter properties from new systems that do not have high-quality stellar kinematics.

• Research Organization: Texas A & M Univ., College Station, TX (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: de-sc0010813; SC0010813
• OSTI ID: 1630203
• Alternate ID(s): OSTI ID: 1611529
• Journal Information: Monthly Notices of the Royal Astronomical Society, Journal Name: Monthly Notices of the Royal Astronomical Society Vol. 482 Journal Issue: 3; ISSN 0035-8711
• Publisher: Oxford University Press
• Country of Publication: United Kingdom
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
kinematics and dynamics of galaxies
local group
dark matter
theory of cosmology