Search for line-like signals in the all-sky Fermi-LAT data

Li, Shang; Xia, Zi-Qing; Liang, Yun-Feng; Duan, Kai-Kai; Shen, Zhao-Qiang; Li, Xiang; Liu, Feng; Yuan, Qiang; Fan, Yi-Zhong; Chang, Jin

doi:10.1103/physrevd.99.123519

Cited by 10 publications

(6 citation statements)

References 41 publications

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“…A search for such gamma-ray spectrum can be done from the H.E.S.S. and Fermi-LAT data [50,51]. Non-observation of such gamma ray emission from dwarf galaxies could serve as an evidence for this model.…”

Section: Discussionmentioning

confidence: 99%

Galactic positron excess from selectively enhanced dark matter annihilation

2020

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Precision measurements of the positron flux in cosmic ray have revealed an unexplained bump in the spectrum around E 300 GeV, not clearly attributable to known astrophysical processes. We propose annihilation of dark matter of mass mχ = 780 GeV with a late-time cross section σv = 4.63 × 10 −24 cm 3 s −1 as a possible source. The nonmonotonic dependence of the annihilation rate on dark matter velocity, owing to a selective p-wave Sommerfeld enhancement, allows such a large signal from the Milky Way without violating corresponding constraints from CMB and dwarf galaxy observations. We briefly explore other signatures of this scenario, and outline avenues to test it in future experiments.

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Section: Discussionmentioning

confidence: 99%

Galactic positron excess from selectively enhanced dark matter annihilation

2020

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“…Great efforts have been paid to search for lines with Fermi Large Area Telescope (LAT) (Atwood et al 2009), but no significant signal has been found up to now (Abdo et al 2010;Vertongen & Weniger 2011;Ackermann et al 2012b;Bringmann et al 2012;Weniger 2012;Tempel et al 2012a;Su & Finkbeiner 2012a,b;Huang et al 2012b;Tempel et al 2012b;Ackermann et al 2013;Hektor et al 2013;Albert et al 2014;Ackermann et al 2015;Anderson et al 2016;Liang et al 2016a,b;Quincy Adams et al 2016;Liang et al 2017;Li et al 2019). Interestingly, some tentative lines have been reported above 3σ.…”

Section: Introductionmentioning

confidence: 99%

“…Another tentative line was found at ∼ 43 GeV in a GCls sample with a global significance of 3.0σ using 7.1-yr LAT P8R2 data (Liang et al 2016a). However, it does not appear in the Galactic center (Ackermann et al 2015), Milky Way satellites (Liang et al 2016b) and subhalos (Liang et al 2017;Li et al 2019). γ-ray line searches have also been performed with other telescopes such as DAMPE (Shen et al 2019), H.E.S.S.…”

Section: Introductionmentioning

confidence: 99%

Search for line-like and box-shaped spectral features from nearby galaxy clusters with 11.4 years of Fermi LAT data

Shen,

Xia,

Fan

2021

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Sharp spectral structures in the γ-ray band are an important dark matter (DM) signature. Previously, a tentative line feature at ∼ 43 GeV is reported in 16 nearby galaxy clusters (GCls) with 7.1 years of Fermi -LAT data, whose TS value is ∼ 16.7. In this work, we search for line signals and box-shaped structures using the stacked data from those 16 GCls with 11.4-yr P8R3 data. There is still a hint at ∼ 42 GeV, dominated by the radiation of Virgo and Ophiuchus clusters. Though the TS value was high up to 21.2 in October 2016, currently it has dropped to 13.1. Moreover, the TS value at ∼ 42 GeV decreases to 2.4 when the EDISP2 data are excluded from the analysis. Consequently, we do not find any statistically significant line-like signal and then set up the 95% confidence level upper limits on the thermally averaged cross section of DM annihilating into double photons. The same line search has been carried out for an alternative GCl sample from the Two Micron All-Sky Survey but no any evidence has been found. We also search for box-shaped features in those 16 baseline GCls.No signal is found as well and the corresponding upper limits on the annihilation cross section are given.

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“…The gamma-ray line above 10 GeV is one of the most important characteristic signals in the indirect detection of dark matter, as hardly any other astrophysical process can produce such kind of structure. Many works have been carried out on gamma-ray line search using the Fermi-LAT data, but only some tentative signals with low confidence are found so far [13][14][15][16][17][18], such as the line candidate found at about 43 GeV, which can also be interpreted as the product of annihilation of dark matter particles [19].…”

Section: Introductionmentioning

confidence: 99%

Optimal gamma-ray selections for monochromatic line searches with DAMPE

Xu¹,

Duan²,

Jiang³

et al. 2021

Preprint

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The DArk Matter Particle Explorer (DAMPE) is a space high-energy cosmic-ray detector covering a wide energy band with a high energy resolution. One of the key scientific goals of DAMPE is to carry out indirect detection of dark matter by searching for high-energy gamma-ray line structure. To promote the sensitivity of gamma-ray line search with DAMPE, it is crucial to improve the acceptance and energy resolution of gamma-ray photons. In this paper, we quantitatively prove that the photon sample with the largest ratio of acceptance to energy resolution is optimal for line search. We therefore develop a line-search sample specifically optimized for the line search.Meanwhile, in order to increase the statistics, we also selected the so called BGO-only photons that convert into e + e − pairs only in the BGO calorimeter. The standard, the line-search, and the BGO-only photon samples are then tested for line search individually and collectively. The results show that a significantly improved limit could be obtained from an appropriate combination of the date sets, and the increase is about 20% for the highest case compared with using the standard sample only.

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Search for line-like signals in the all-sky Fermi-LAT data

Cited by 10 publications

References 41 publications

Galactic positron excess from selectively enhanced dark matter annihilation

Galactic positron excess from selectively enhanced dark matter annihilation

Search for line-like and box-shaped spectral features from nearby galaxy clusters with 11.4 years of Fermi LAT data

Optimal gamma-ray selections for monochromatic line searches with DAMPE

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