Searching for dark matter sub-structure with HAWC

Authors

A. U. Abeysekara, University of Utah
A. Albert, Los Alamos National Laboratory
R. Alfaro, Universidad Nacional Autónoma de México
C. Alvarez, Universidad Autónoma de Chiapas
R. Arceo, Universidad Autónoma de Chiapas
J. C. Arteaga-Valazquez, Universidad Michoacana de San Nicolás de Hidalgo
Chad Brisbois, Michigan Technological UniversityFollow
H. Fleischhack, Michigan Technological University
Binita Hona, Michigan Technological UniversityFollow
P. Huntemeyer, Michigan Technological University
et al.

Document Type

Article

Publication Date

7-2019

Department

Department of Physics

Abstract

Numerical simulations show that the dark matter halos surrounding galaxies are expected to contain many over-densities or sub-halos. The most massive of these sub-halos can be optically observed in the form of dwarf galaxies. However, most lower mass sub-halos are predicted to exist as dark dwarf galaxies: sub-halos like dwarf galaxies with no luminous counterpart. It may be possible to detect these unseen sub-halos from gamma-ray signals originating from dark matter annihilation. The High Altitude Water Cherenkov Observatory (HAWC) is a very high energy (500 GeV to >100 TeV) gamma ray detector with a wide field-of-view and near continuous duty cycle, making HAWC ideal for unbiased sky surveys. We perform a search for gamma ray signals from dark dwarfs in the Milky Way halo with HAWC. We perform a targeted search of HAWC gamma-ray sources which have no known association with lower-energy counterparts, based on an unbiased survey of the entire sky. With no sources found to strongly prefer dark matter models, we calculate the ability of HAWC to observe dark dwarfs. We also compute the HAWC sensitivity to potential future detections for a given model of dark matter substructure. Assuming thermal dark matter, we find the corresponding J-factor of a dark dwarf required to reach the HAWC detection criterion is 5.79× 10²⁰ GeV² cm⁻⁵ sr for one particular set of dark matter assumptions. HAWC is found to be able to competitively constrain dark matter annihilation from discovered halos with J-factors on the scale of 10¹⁹ GeV² cm⁻⁵ sr or greater, with better constraints obtained on dark matter models with >10 TeV masses and sources that transit overhead.

Publisher's Statement

© 2019 The Author(s). Publisher’s version of record: https://doi.org/10.1088/1475-7516/2019/07/022

Publication Title

Journal of Cosmology and Astroparticle Physics

Recommended Citation

Abeysekara, A. U., Albert, A., Alfaro, R., Alvarez, C., Arceo, R., Arteaga-Valazquez, J. C., Brisbois, C., Fleischhack, H., Hona, B., Huntemeyer, P., & et al. (2019). Searching for dark matter sub-structure with HAWC. Journal of Cosmology and Astroparticle Physics, 2019, 1-19. http://doi.org/10.1088/1475-7516/2019/07/022
Retrieved from: https://digitalcommons.mtu.edu/michigantech-p/647

Creative Commons License

This work is licensed under a Creative Commons Attribution 3.0 License.

Version

Publisher's PDF