We report on the analysis of the 10–1000 TeV large-scale sidereal anisotropy of Galactic cosmic rays (GCRs) with the data collected by the Tibet Air Shower Array from 1995 October to 2010 February. In this analysis, we improve the energy estimate and extend the decl. range down to −30°. We find that the anisotropy maps above 100 TeV are distinct from that at a multi-TeV band. The so-called tail-in and loss-cone features identified at low energies get less significant, and a new component appears at ∼100 TeV. The spatial distribution of the GCR intensity with an excess (7.2σ pre-trial, 5.2σ post-trial) and a deficit (−5.8σ pre-trial) are observed in the 300 TeV anisotropy map, in close agreement with IceCube’s results at 400 TeV. Combining the Tibet results in the northern sky with IceCube’s results in the southern sky, we establish a full-sky picture of the anisotropy in hundreds of TeV band. We further find that the amplitude of the first order anisotropy increases sharply above ∼100 TeV, indicating a new component of the anisotropy. All these results may shed new light on understanding the origin and propagation of GCRs.
HESS J1843–033 is a very high energy gamma-ray source whose origin remains unidentified. This work presents, for the first time, the energy spectrum of gamma rays beyond 100 TeV from the HESS J1843–033 region using the data recorded by the Tibet air shower array and its underground muon detector array. A gamma-ray source with an extension of 0.°34 ± 0.°12 is successfully detected above 25 TeV at (α, δ) = (281.°09 ± 0.°10, −3.°76 ± 0.°09) near HESS J1843–033 with a statistical significance of 6.2σ, and the source is named TASG J1844–038. The position of TASG J1844–038 is consistent with those of HESS J1843–033, eHWC J1842–035, and LHAASO J1843–0338. The measured gamma-ray energy spectrum in 25 TeV < E < 130 TeV is described with
dN
/
dE
=
(
9.70
±
1.89
)
×
10
−
16
(E/40 TeV)−3.26±0.30 TeV−1 cm−2 s−1, and the spectral fit to the combined spectra of HESS J1843–033, LHAASO J1843–0338, and TASG J1844–038 implies the existence of a cutoff at 49.5 ± 9.0 TeV. Associations of TASG J1844–038 with SNR G28.6–0.1 and PSR J1844–0346 are also discussed in detail for the first time.
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