NPTFit: A Code Package for Non-Poissonian Template Fitting

Mishra-Sharma, Siddharth; Rodd, Nicholas L.; Safdi, Benjamin R.

doi:10.3847/1538-3881/aa6d5f

Cited by 44 publications

(59 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[43]), described in more detail in the Supplementary Material. To this end, we perform a template fitting analysis (using NPTFit [44]) with 413 weeks of Fermi Pass 8 data collected from August 4, 2008 to July 7, 2016. We restrict to the UltracleanVeto event class; furthermore, we only use the top quartile of events as ranked by point-spread function (PSF).…”

Section: Discussionmentioning

confidence: 99%

γ -ray Constraints on Decaying Dark Matter and Implications for IceCube

et al. 2017

Self Cite

View full text Add to dashboard Cite

Utilizing the Fermi measurement of the gamma-ray spectrum toward the Inner Galaxy, we derive some of the strongest constraints to date on the dark matter (DM) lifetime in the mass range from hundreds of MeV to above an EeV. Our profile-likelihood based analysis relies on 413 weeks of Fermi Pass 8 data from 200 MeV to 2 TeV, along with up-to-date models for diffuse gamma-ray emission within the Milky Way. We model Galactic and extragalactic DM decay and include contributions to the DM-induced gamma-ray flux resulting from both primary emission and inverse-Compton scattering of primary electrons and positrons. For the extragalactic flux, we also calculate the spectrum associated with cascades of high-energy gamma-rays scattering off of the cosmic background radiation. We argue that a decaying DM interpretation for the 10 TeV-1 PeV neutrino flux observed by IceCube is disfavored by our constraints. Our results also challenge a decaying DM explanation of the AMS-02 positron flux. We interpret the results in terms of individual final states and in the context of simplified scenarios such as a hidden-sector glueball model.

show abstract

Section: Discussionmentioning

confidence: 99%

γ -ray Constraints on Decaying Dark Matter and Implications for IceCube

et al. 2017

Self Cite

View full text Add to dashboard Cite

show abstract

“…We adopted a 30 • ×30 • region-of-interest around the Galactic Center, masking the regions within 1 • of the Galactic Plane and around the 68% containment radii of the 300 brightest and most variable sources contained in the 3FGL catalog (Acero et al 2015). 10 To obtain the results shown in this figure, we performed a template based analysis of this dataset, implemented using NPTFit (Mishra-Sharma et al 2017). The fit includes templates intended to describe the Galactic diffuse emission, isotropic flux, emission associated with the Fermi bubbles (Su et al 2010), emission from the known 3FGL sources, and the flux corresponding to the excess.…”

Section: Galprop Analysismentioning

confidence: 99%

Comment on “Characterizing the population of pulsars in the Galactic bulge with the Fermi large area telescope” [arXiv:1705.00009v1]

Bartels

Linden

Mishra-Sharma

et al. 2018

Physics of the Dark Universe

Self Cite

View full text Add to dashboard Cite

The Fermi-LAT Collaboration recently presented a new catalog of gamma-ray sources located within the 40 • × 40 • region around the Galactic Center (Ajello et al. 2017) -the Second Fermi Inner Galaxy (2FIG) catalog. Utilizing this catalog, they analyzed models for the spatial distribution and luminosity function of sources with a pulsar-like gamma-ray spectrum. Ajello et al. (2017) v1 also claimed to detect, in addition to a disklike population of pulsar-like sources, an approximately 7σ preference for an additional centrally concentrated population of pulsar-like sources, which they referred to as a "Galactic Bulge" population. Such a population would be of great interest, as it would support a pulsar interpretation of the gamma-ray excess that has long been observed in this region. In an effort to further explore the implications of this new source catalog, we attempted to reproduce the results presented by the Fermi-LAT Collaboration, but failed to do so. Mimicking as closely as possible the analysis techniques undertaken in Ajello et al. (2017), we instead find that our likelihood analysis favors a very different spatial distribution and luminosity function for these sources. Most notably, our results do not exhibit a strong preference for a "Galactic Bulge" population of pulsars. Furthermore, we find that masking the regions immediately surrounding each of the 2FIG pulsar candidates does not significantly impact the spectrum or intensity of the Galactic Center gamma-ray excess. Although these results refute the claim of strong evidence for a centrally concentrated pulsar population presented in Ajello et al. (2017), they neither rule out nor provide support for the possibility that the Galactic Center excess is generated by a population of low-luminosity and currently largely unobserved pulsars. In a spirit of maximal openness and transparency, we have made our analysis code available at https://github.com/bsafdi/GCE-2FIG.

show abstract

“…We implement template fitting with the package NPTFit [77], which uses MultiNest [78,79] by default, but we have employed Minuit [80] in our analysis.…”

Section: Methodsmentioning

confidence: 99%

Mapping extragalactic dark matter annihilation with galaxy surveys: A systematic study of stacked group searches

2018

Self Cite

View full text Add to dashboard Cite

Dark matter in the halos surrounding galaxy groups and clusters can annihilate to high-energy photons. Recent advancements in the construction of galaxy group catalogs provide many thousands of potential extragalactic targets for dark matter. In this paper, we outline a procedure to infer the dark matter signal associated with a given galaxy group. Applying this procedure to a catalog of sources, one can create a full-sky map of the brightest extragalactic dark matter targets in the nearby Universe (z 0.03), supplementing sources of dark matter annihilation from within the Local Group. As with searches for dark matter in dwarf galaxies, these extragalactic targets can be stacked together to enhance the signals associated with dark matter. We validate this procedure on mock Fermi gamma-ray data sets using a galaxy catalog constructed from the DarkSky N -body cosmological simulation and demonstrate that the limits are robust, at O(1) levels, to systematic uncertainties on halo mass and concentration. We also quantify other sources of systematic uncertainty arising from the analysis and modeling assumptions. Our results suggest that a stacking analysis using galaxy group catalogs provides a powerful opportunity to discover extragalactic dark matter and complements existing studies of Milky Way dwarf galaxies.

show abstract

NPTFit: A Code Package for Non-Poissonian Template Fitting

Cited by 44 publications

References 55 publications

γ -ray Constraints on Decaying Dark Matter and Implications for IceCube

γ -ray Constraints on Decaying Dark Matter and Implications for IceCube

Comment on “Characterizing the population of pulsars in the Galactic bulge with the Fermi large area telescope” [arXiv:1705.00009v1]

Mapping extragalactic dark matter annihilation with galaxy surveys: A systematic study of stacked group searches

Contact Info

Product

Resources

About