Fermi LAT Search for Internal Bremsstrahlung Signatures from Dark Matter Annihilation

By T. Bringmann, Xiaoyuan Huang, A. Ibarra, S. Vogl, Christoph Weniger. 2012

394 citations recorded by the source corpus.

A commonly encountered obstacle in indirect searches for galactic dark matter is how to disentangle possible signals from astrophysical backgrounds. Given that such signals are most likely subdominant, the search for pronounced spectral features plays a key role for indirect detection experiments; monochromatic gamma-ray lines or similar features related to internal bremsstrahlung, in particular, provide smoking gun signatures. We perform a dedicated search for the latter in the data taken by the Fermi gamma-ray space telescope during its first 43 months. To this end, we use a new adaptive procedure to select optimal target regions that takes into account both standard and contracted dark matter profiles. The behaviour of our statistical method is tested by a subsampling analysis of the full sky data and found to reproduce the theoretical expectations very well. The limits on the dark matter annihilation cross-section that we derive are stronger than what can be obtained from the observation of dwarf galaxies and, at least for the model considered here, collider searches. While these limits are still not quite strong enough to probe annihilation rates expected for thermally produced dark matter, future prospects to do so are very good. In fact, we already find a weak indication, with a significance of 3.1σ (4.3σ) when (not) taking into account the look-elsewhere effect, for an internal bremsstrahlung-like signal that would correspond to a dark matter mass of ~150 GeV; the same signal is also well fitted by a gamma-ray line at around 130 GeV. Although this would be a fascinating possibility, we caution that a much more dedicated analysis and additional data will be necessary to rule out or confirm this option.

Subfields: Materials Chemistry, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/9bafee3f681f77ebcb28f16de9a65e8eb07f3117

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Citations in the corpus

Numerical simulations of the dark universe: State of the art and the next decade (2012, background): “Intriguingly, the recently reported 130 GeV gamma-ray line from the Galactic Center [105–108] appears to be offset by about 1.”
Fermi 130 GeV gamma-ray excess and dark matter annihilation in sub-haloes and in the Galactic centre (2012, background): “However, other narrow peak-like spectra like from internal bremsstrahlung [3] or narrow boxes due to massive intermediate particles [10] are still allowed within present Fermi-LAT energy resolution.”
Optimized dark matter searches in deep observations of Segue 1 with MAGIC (2013, background): “In addition, it is worth mentioning that there is a recently claimed hint of a line-like signal at ∼130 GeV in the Fermi -LAT data of the GC region [40, 64]: if the observed signal originates from direct DM annihilation into two photons, the WIMP particle should have a mass of mχ = 129±2.”
A Tentative Gamma-Ray Line from Dark Matter Annihilation at the Fermi Large Area Telescope (2012, methodology): “eﬁne the optimal target region as the set of pixels To for which the integrated SNR RTo = P q i∈To µi P i∈To ci , (2.5) is maximized. To ﬁnd To, we use the approximate but eﬃcient algorithm from Ref. [49]. The resulting target regions, optimized for our ﬁve reference DM proﬁles, are shown in the lef”
WIMP dark matter candidates and searches—current status and future prospects (2017, background): “Another excess in the Fermi-LAT data from the GC was reported in 2012 by [337, 338].”
An Introduction to Particle Dark Matter (2019, methodology): “From data by the FermiLAT(5) Bringmann [18] and Weniger [79] identified a 130 GeV line from the galactic center that was initially explained by recurring to DM annihilation.”
Search for gamma-ray spectral lines with the Fermi Large Area Telescope and dark matter implications (2013, neutral): “This feature has been detected more significantly in spectra containing γ rays near the GC [49, 39, 50, 51], nearby galaxy clusters [52], and unassociated LAT sources [53] (see also [54]).”
MadDM v.3.0: A comprehensive tool for dark matter studies (2018, background): “Final state radiation in dark matter annihilation: the case of internal bremsstrahlung In this section we show how MadDM can easily reproduce the internal bremsstrahlung phenomenon in 2 → 3 annihilation processes [89–95].”
Sensitivity projections for dark matter searches with the Fermi large area telescope (2016, methodology): “[57, 241] used somewhat different ROIs that were created by selecting a set of pixels with the largest expected signal-to-noise given the observed data and a similar set of DM density profiles; however the difference in ROIs does not significantly alter the results.”
Double-Disk Dark Matter (2013, background): “These could include observations such as the recently reported Fermi line [3,4], which is challenging to explain without significant boost factors or tuned scenarios (many of which are summarized in [5, 6]).”
The dark Z′ portal: direct, indirect and collider searches (2013, background): “The 130 GeV gamma-ray line observed in the Fermi-LAT data [32, 33] has appeared as a smoking gun signature for a 130 GeV DM particle which has a fairly large annihilation cross section into γγ.”
Gamma Ray Signals from Dark Matter: Concepts, Status and Prospects (2012, background): “ e in the data from around 20GeV to at least 300GeV (we checked this explicitly by performing line searches along the galactic disc, as well as a subsampling analysis of anti-GC data – see also Refs. [13, 14, 246]; conﬂicting claims [245, 247] may likely be explained as statistical ﬂuctuations at th”