Spectral analysis of the gamma-ray background near the dwarf Milky Way satellite Segue 1: Improved limits on the cross section of neutralino dark matter annihilation

Baushev, A. N.; Federici, S.; Pohl, M.

doi:10.1103/physrevd.86.063521

Cited by 24 publications

(33 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In light of this result for the Bayesian parameter inference, we do not expect to find Bayesian evidence for the DM signal hypothesis from either data set when we perform a Bayesian model comparison later in this section. 13 We make use the software pippi [87] for plotting the marginalised posterior distributions and profile likelihoods. β RET II ≈ 0.60 (β RET II ≈ 0.53), which is considerably lower than the all-sky value of 1.…”

Section: Analysis Of Reticulum IImentioning

confidence: 99%

A global analysis of dark matter signals from 27 dwarf spheroidal galaxies using 11 years of Fermi-LAT observations

Hoof

Geringer-Sameth

Trotta

2020

J. Cosmol. Astropart. Phys.

119

View full text Add to dashboard Cite

We perform a search for a dark matter signal in Fermi-LAT gamma-ray data from 27 Milky Way dwarf spheroidal galaxies with spectroscopically measured J -factors. Our analysis properly includes uncertainties in J -factors and background normalisations and systematically compares results from a Bayesian and a frequentist perspective. We revisit the dwarf spheroidal galaxy Reticulum II, confirming that the purported gamma-ray excess seen in Pass 7 data is much weaker in Pass 8, independently of the statistical approach adopted. We introduce for the first time posterior predictive distributions to accurately quantify the probability of a dark matter detection from another dwarf galaxy given a tentative excess. A global analysis including all 27 dwarfs shows no indication for a signal in the τ + τ − and bb channels. We present new stringent Bayesian and frequentist upper limits on the velocity-averaged annihilation cross section as a function of the dark matter mass. The best-fit dark matter parameters associated with the Galactic Centre excess are excluded at more than 95% confidence level/posterior probability in the frequentist/Bayesian framework. However, from a Bayesian model comparison perspective, dark matter annihilation within the dwarfs is not strongly disfavoured compared to a background-only model. These results constitute the highest exposure analysis on the most complete sample of dwarfs to date.

show abstract

Section: Analysis Of Reticulum IImentioning

confidence: 99%

A global analysis of dark matter signals from 27 dwarf spheroidal galaxies using 11 years of Fermi-LAT observations

Hoof

Geringer-Sameth

Trotta

2020

J. Cosmol. Astropart. Phys.

119

View full text Add to dashboard Cite

show abstract

“…This motivates the use of Milky Way dwarf galaxies as annihilation targets, an idea first suggested by [38] and further explored in [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58] (among others). These sources have very high mass-to-light ratios and are free of any known astrophysical sources of gamma-rays.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive search for dark matter annihilation in dwarf galaxies

2015

View full text Add to dashboard Cite

We present a new formalism designed to discover dark matter annihilation occurring in the Milky Way's dwarf galaxies. The statistical framework extracts all available information in the data by simultaneously combining observations of all the dwarf galaxies and incorporating the impact of particle physics properties, the distribution of dark matter in the dwarfs, and the detector response. The method performs maximally powerful frequentist searches and produces confidence limits on particle physics parameters. Probability distributions of test statistics under various hypotheses are constructed exactly, without relying on large sample approximations. The derived limits have proper coverage by construction and claims of detection are not biased by imperfect background modeling. We implement this formalism using data from the Fermi Gamma-ray Space Telescope to search for an annihilation signal in the complete sample of Milky Way dwarfs whose dark matter distributions can be reliably determined. We find that the observed data is consistent with background for each of the dwarf galaxies individually as well as in a joint analysis. The strongest constraints are at small dark matter particle masses. Taking the median of the systematic uncertainty in dwarf density profiles, the cross section upper limits are below the pure s-wave weak scale relic abundance value (2.2×10 −26 cm 3 s −1 ) for dark matter masses below 26 GeV (for annihilation into bb), 29 GeV (τ + τ − ), 35 GeV (uū, dd, ss, cc, and gg), 6 GeV (e + e − ), and 114 GeV (γγ). For dark matter particle masses less than 1 TeV, these represent the strongest limits obtained to date using dwarf galaxies.

show abstract

“…The search for γ-rays in dwarf galaxies [e.g. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] provides an alternative to searches in regions that enjoy superior statistics but suffer from complicated backgrounds (e.g. the Galactic center [21][22][23][24][25][26][27][28][29][30][31]).…”

mentioning

confidence: 99%

Indication of Gamma-Ray Emission from the Newly Discovered Dwarf Galaxy Reticulum II

et al. 2015

View full text Add to dashboard Cite

We present a search for γ-ray emission from the direction of the newly discovered dwarf galaxy Reticulum II. Using Fermi-LAT data, we detect a signal that exceeds expected backgrounds between ∼ 2 − 10 GeV and is consistent with annihilation of dark matter for particle masses less than a few × 10 2 GeV. Modeling the background as a Poisson process based on Fermi-LAT diffuse models, and taking into account trials factors, we detect emission with p-value less than 9.8 × 10 −5 (> 3.7σ). An alternative, model-independent treatment of background reduces the significance, raising the p-value to 9.7 × 10 −3 (2.3σ). Even in this case, however, Reticulum II has the most significant γ-ray signal of any known dwarf galaxy. If Reticulum II has a dark matter halo that is similar to those inferred for other nearby dwarfs, the signal is consistent with the s-wave relic abundance cross section for annihilation.PACS numbers: 95.35.+d, 95.55.Ka, 98.56.Wm Dark matter's non-gravitational interactions have profound implications for particle physics beyond the Standard Model, motivating searches for high-energy photons produced via annihilation. The search for γ-rays in dwarf galaxies [e.g.

show abstract

Spectral analysis of the gamma-ray background near the dwarf Milky Way satellite Segue 1: Improved limits on the cross section of neutralino dark matter annihilation

Cited by 24 publications

References 30 publications

A global analysis of dark matter signals from 27 dwarf spheroidal galaxies using 11 years of Fermi-LAT observations

A global analysis of dark matter signals from 27 dwarf spheroidal galaxies using 11 years of Fermi-LAT observations

Comprehensive search for dark matter annihilation in dwarf galaxies

Indication of Gamma-Ray Emission from the Newly Discovered Dwarf Galaxy Reticulum II

Contact Info

Product

Resources

About