Searching for dark matter annihilation in recently discovered Milky Way satellites with Fermi-LAT

Journal Article · Tue Jan 10 00:00:00 EST 2017 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/834/2/110· OSTI ID:22869526

Albert, A.; Wood, M. ^[1]; Anderson, B.; Meyer, M.; Sánchez-Conde, M. ^[2]; Bechtol, K. ^[3]; Drlica-Wagner, A. ^[4]; Strigari, L. ^[5]; Abbott, T. M. C. ^[6]; Abdalla, F. B.; Brooks, D. ^[7]; Benoit-Lévy, A.; Bertin, E. ^[8]; Bernstein, G. M. ^[9]; Bernstein, R. A. ^[10]; Burke, D. L. ^[11]; Rosell, A. Carnero ^[12]; others, and

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1. Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)
2. Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm (Sweden)
3. Dept. of Physics and Wisconsin IceCube Particle Astrophysics Center, University of Wisconsin, Madison, WI 53706 (United States)
4. Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States)
5. George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, and Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States)
6. Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory, Casilla 603, La Serena (Chile)
7. Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)
8. CNRS, UMR 7095, Institut d’Astrophysique de Paris, F-75014, Paris (France)
9. Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States)
10. Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
11. Kavli Institute for Particle Astrophysics and Cosmology, P.O. Box 2450, Stanford University, Stanford, CA 94305 (United States)
12. Laboratório Interinstitucional de e-Astronomia—LIneA, Rua Gal. José Cristino 77, Rio de Janeiro, RJ—20921-400 (Brazil)

We search for excess γ-ray emission coincident with the positions of confirmed and candidate Milky Way satellite galaxies using six years of data from the Fermi Large Area Telescope (LAT). Our sample of 45 stellar systems includes 28 kinematically confirmed dark-matter-dominated dwarf spheroidal galaxies (dSphs) and 17 recently discovered systems that have photometric characteristics consistent with the population of known dSphs. For each of these targets, the relative predicted γ-ray flux due to dark matter annihilation is taken from kinematic analysis if available, and estimated from a distance-based scaling relation otherwise, assuming that the stellar systems are DM-dominated dSphs. LAT data coincident with four of the newly discovered targets show a slight preference (each ∼2σ local) for γ-ray emission in excess of the background. However, the ensemble of derived γ-ray flux upper limits for individual targets is consistent with the expectation from analyzing random blank-sky regions, and a combined analysis of the population of stellar systems yields no globally significant excess (global significance <1σ). Our analysis has increased sensitivity compared to the analysis of 15 confirmed dSphs by Ackermann et al. The observed constraints on the DM annihilation cross section are statistically consistent with the background expectation, improving by a factor of ∼2 for large DM masses (m{sub DM,b b-bar }≳1 TeV and m{sub DM,τ{sup +}τ{sup −}}≳70 GeV) and weakening by a factor of ∼1.5 at lower masses relative to previously observed limits.

• OSTI ID: 22869526
• Journal Information: Astrophysical Journal, Vol. 834, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ANNIHILATION
COMPARATIVE EVALUATIONS
COSMIC PHOTONS
CROSS SECTIONS
DISTANCE
DWARF STARS
EMISSION
GEV RANGE 10-100
MASS
MILKY WAY
NONLUMINOUS MATTER
RANDOMNESS
SATELLITES
SCALING
SENSITIVITY
TELESCOPES
TEV RANGE 01-10