Ultra-high-energy γ-ray emission associated with the tail of a bow-shock pulsar wind nebula

In this study, we present a comprehensive analysis of an unidentified point-like ultra-high-energy (UHE) γ-ray source, designated as 1LHAASO J1740+0948u, situated in the vicinity of the middle-aged pulsar PSR J1740+1000. The detection significance reached 17.1 σ (9.4 σ) above 25 TeV (100 TeV). The s...

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Language:English
Published: Elsevier 2025-04-01
Series:The Innovation
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Online Access:http://www.sciencedirect.com/science/article/pii/S2666675825000050
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description In this study, we present a comprehensive analysis of an unidentified point-like ultra-high-energy (UHE) γ-ray source, designated as 1LHAASO J1740+0948u, situated in the vicinity of the middle-aged pulsar PSR J1740+1000. The detection significance reached 17.1 σ (9.4 σ) above 25 TeV (100 TeV). The source energy spectrum extended up to 300 TeV, which was well fitted by a log-parabola function with N0 = (1.93 ± 0.23) × 10−16 TeV−1 cm−2 s−1, α = 2.14 ± 0.27, and β = 1.20 ± 0.41 at E0 = 30 TeV. The associated pulsar, PSR J1740+1000, resides at a high galactic latitude (Gb) and powers a bow-shock pulsar wind nebula (BSPWN) with an extended X-ray tail. The best-fit position of the γ-ray source appeared to be shifted by 0.2° with respect to the pulsar position. As (1) the currently identified pulsar halos do not demonstrate such offsets and (2) the centroid of the γ ray emission is approximately located at the extension of the X-ray tail, we speculate that the UHE γ-ray emission may originate from re-accelerated electron/positron pairs that are advected away in the bow-shock tail.
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spelling doaj-art-b789e8d53e884674b9d1dcb0b8916ca32025-08-20T03:17:57ZengElsevierThe Innovation2666-67582025-04-016410080210.1016/j.xinn.2025.100802Ultra-high-energy γ-ray emission associated with the tail of a bow-shock pulsar wind nebulaIn this study, we present a comprehensive analysis of an unidentified point-like ultra-high-energy (UHE) γ-ray source, designated as 1LHAASO J1740+0948u, situated in the vicinity of the middle-aged pulsar PSR J1740+1000. The detection significance reached 17.1 σ (9.4 σ) above 25 TeV (100 TeV). The source energy spectrum extended up to 300 TeV, which was well fitted by a log-parabola function with N0 = (1.93 ± 0.23) × 10−16 TeV−1 cm−2 s−1, α = 2.14 ± 0.27, and β = 1.20 ± 0.41 at E0 = 30 TeV. The associated pulsar, PSR J1740+1000, resides at a high galactic latitude (Gb) and powers a bow-shock pulsar wind nebula (BSPWN) with an extended X-ray tail. The best-fit position of the γ-ray source appeared to be shifted by 0.2° with respect to the pulsar position. As (1) the currently identified pulsar halos do not demonstrate such offsets and (2) the centroid of the γ ray emission is approximately located at the extension of the X-ray tail, we speculate that the UHE γ-ray emission may originate from re-accelerated electron/positron pairs that are advected away in the bow-shock tail.http://www.sciencedirect.com/science/article/pii/S2666675825000050LHAASOγ-ray astronomyBSPWN
spellingShingle Ultra-high-energy γ-ray emission associated with the tail of a bow-shock pulsar wind nebula
The Innovation
LHAASO
γ-ray astronomy
BSPWN
title Ultra-high-energy γ-ray emission associated with the tail of a bow-shock pulsar wind nebula
title_full Ultra-high-energy γ-ray emission associated with the tail of a bow-shock pulsar wind nebula
title_fullStr Ultra-high-energy γ-ray emission associated with the tail of a bow-shock pulsar wind nebula
title_full_unstemmed Ultra-high-energy γ-ray emission associated with the tail of a bow-shock pulsar wind nebula
title_short Ultra-high-energy γ-ray emission associated with the tail of a bow-shock pulsar wind nebula
title_sort ultra high energy γ ray emission associated with the tail of a bow shock pulsar wind nebula
topic LHAASO
γ-ray astronomy
BSPWN
url http://www.sciencedirect.com/science/article/pii/S2666675825000050