Searching for dark matter sub-structure with HAWC

Abeysekara, A. U.; Albert, A.; Alfaro, R.; Álvarez, C.; Arceo, R.; Arteaga‐Velázquez, J. C.; Rojas, D. Avila; Solares, H. A. Ayala; Belmont‐Moreno, E.; BenZvi, S.; Brisbois, C.; Caballero-Mora, K. S.; Carramiñana, A.; Casanova, S.; Cotzomi, J.; León, S. Coutińo de; León, C. De; Fuente, Eduardo de la; Dichiara, S.; Dingus, B. L.; DuVernois, Michael; Díaz-Vélez, J. C.; Engel, Kristi; Espinoza, C.; Fleischhack, Henrike; Fraija, N.; Galván-Gaméz, A.; García-González, J. A.; González, M. M.; Goodman, J. A.; Harding, J. Patrick; Hona, B.; Hueyotl-Zahuantitla, F.; Hüntemeyer, P.; Iriarte, A.; Lara, A.; Lee, W. H.; Vargas, H. León; Linnemann, J.; Longinotti, A. L.; Luis-Raya, G.; Lundeen, J.; Malone, K.; Marinelli, S. S.; Martı́nez, O.; Martínez-Castellanos, I.; Martínez-Castro, J.; Matthews, John; Miranda-Romagnoli, P.; Moreno, E.; Mostafá, M.; Nayerhoda, A.; Nellen, L.; Newbold, M.; Noriega-Papaqui, R.; Pérez-Pérez, E. G.; Ren, Z.; Rho, Chang Dong; Rivière, C.; Rosa-González, D.; Rosenberg, M.; Salazar, H.; Greus, F. Salesa; Sandoval, A.; Schneider, M.; Sinnis, G.; Smith, A. J.; Springer, R. W.; Tollefson, K.; Torres, I.; Vianello, G.; Weisgarber, T.; Wood, J.; Yapici, T.; Zepeda, A.; Zhou, H.; Álvarez, José David Ruiz

doi:10.1088/1475-7516/2019/07/022

Cited by 16 publications

(16 citation statements)

References 49 publications

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“…The limited sensitivity of ARGO-YBJ is mainly due to the presence of the Sun shadow whose displacement is comparable to the detector angular resolution. This problem should be at least partially solved by EAS arrays as HAWC (Abeysekara et al 2013), currently running, and LHAASO (Cao 2014), in construction, owing to their capability to reject a large fraction of the hadron-induced air showers. The sensitivity predicted for LHAASO (He 2018) is shown in Fig.6.…”

Section: Discussionmentioning

confidence: 99%

Search for Gamma-Ray Emission from the Sun during Solar Minimum with the ARGO-YBJ Experiment

Bartoli¹,

Bernardini²,

Bi³

et al. 2019

ApJ

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The hadronic interaction of cosmic rays with solar atmosphere can produce high energy gamma rays. The gamma-ray luminosity is correlated both with the flux of primary cosmic rays and the intensity of the solar magnetic field. The gamma rays below 200 GeV have been observed by Fermi without any evident energy cutoff. The bright gamma-ray flux above 100 GeV has been detected only during solar minimum. The only available data in TeV range come from the HAWC observations, however outside the solar minimum. The ARGO-YBJ dataset has been used to search for sub-TeV/TeV gamma rays from the Sun during the solar minimum from 2008 to 2010, the same time period covered by the Fermi data. A suitable model containing the Sun shadow, solar disk emission and inverse-Compton emission has been developed, and the chi-square minimization method was used to quantitatively estimate the disk gamma-ray signal. The result shows that no significant gamma-ray signal is detected and upper limits to the gamma-ray flux at 0.3−7 TeV are set at 95% confidence level. In the low energy range these limits are consistent with the extrapolation of the Fermi-LAT measurements taken during solar minimum and are compatible with a softening of the gamma-ray spectrum below 1 TeV. They provide also an experimental upper bound to any solar disk emission at TeV energies. Models of dark matter annihilation via long-lived mediators predicting gamma-ray fluxes > 10 −7 GeV cm −2 s −1 below 1 TeV are ruled out by the ARGO-YBJ limits.

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Section: Discussionmentioning

confidence: 99%

Search for Gamma-Ray Emission from the Sun during Solar Minimum with the ARGO-YBJ Experiment

Bartoli¹,

Bernardini²,

Bi³

et al. 2019

ApJ

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“…The high-energy SAγ flux during solar minimum has immediate implications for TeV solar gamma-ray searches. In this regime, only ground-based air shower experiments and water Cherenkov telescopes, such as ARGO-YBJ [20], Tibet AS-gamma [21], HAWC [22,23], and LHAASO [24,25] are capable of solar observations. Figure 5 also compares the SAγ flux with the 1-year differential sensitivity of HAWC and LHAASO.…”

Section: B Detection Prospects At Tev Energiesmentioning

confidence: 99%

Unexpected dip in the solar gamma-ray spectrum

Tang

Linden

et al. 2018

Phys. Rev. D

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The solar disk is a bright source of multi-GeV gamma rays, due to the interactions of hadronic cosmic rays with the solar atmosphere. However, the underlying production mechanism is not understood, except that its efficiency must be greatly enhanced by magnetic fields that redirect some cosmic rays from ingoing to outgoing before they interact. To elucidate the nature of this emission, we perform a new analysis of solar atmospheric gamma rays with 9 years of Fermi-LAT data, which spans nearly the full 11-year solar cycle. We detect significant gamma-ray emission from the solar disk from 1 GeV up to 200 GeV. The overall gamma-ray spectrum is much harder (∼ E −2.2 γ ) than the cosmic-ray spectrum (∼ E −2.7 CR ). We find a clear anticorrelation between the solar cycle phase and the gamma-ray flux between 1-10 GeV. Surprisingly, we observe a spectral dip between ∼30-50 GeV in an otherwise power-law spectrum. This was not predicted, is not understood, and may provide crucial clues to the gamma-ray emission mechanism. The flux above 100 GeV, which is brightest during the solar minimum, poses exciting opportunities for HAWC, LHAASO, IceCube, and KM3NeT.

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“…In any case, this immediately questions the conclusion reached in [1], where the brightest subhalo was found, on average, at ∼10 kpc from the Galactic center and at similar distance from Earth. Experimental limits on DM from galactic subhalos, derived from Fermi-LAT [16][17][18][19][20][21][22][23][24] or expected from prolonged operation [25], from HAWC [26,27], or future instruments such as GAMMA 400 [28] and CTA [1,29], should also be impacted by this result.…”

Section: Introductionmentioning

confidence: 99%

γ-ray and ν Searches for Dark-Matter Subhalos in the Milky Way with a Baryonic Potential

et al. 2019

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The distribution of dark-matter (DM) subhalos in our galaxy remains disputed, leading to varying γ-ray and ν flux predictions from their annihilation or decay. In this work, we study how, in the inner galaxy, subhalo tidal disruption from the galactic baryonic potential impacts these signals. Based on state-of-the art modeling of this effect from numerical simulations and semi-analytical results, updated subhalo spatial distributions are derived and included in the CLUMPY code. The latter is used to produce a thousand realizations of the γ-ray and ν sky. Compared to predictions based on DM only, we conclude a decrease of the flux of the brightest subhalo by a factor of 2 to 7 for annihilating DM and no impact on decaying DM: the discovery prospects or limits subhalos can set on DM candidates are affected by the same factor. This study also provides probability density functions for the distance, mass, and angular distribution of the brightest subhalo, among which the mass may hint at its nature: it is most likely a dwarf spheroidal galaxy in the case of strong tidal effects from the baryonic potential, whereas it is lighter and possibly a dark halo for DM only or less pronounced tidal effects.

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Searching for dark matter sub-structure with HAWC

Cited by 16 publications

References 49 publications

Search for Gamma-Ray Emission from the Sun during Solar Minimum with the ARGO-YBJ Experiment

Search for Gamma-Ray Emission from the Sun during Solar Minimum with the ARGO-YBJ Experiment

Unexpected dip in the solar gamma-ray spectrum

γ-ray and ν Searches for Dark-Matter Subhalos in the Milky Way with a Baryonic Potential

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