Structuring Metadata for the Cherenkov Telescope Array

The landscape of ground-based gamma-ray astronomy is changing drastically with the perspective of the Cherenkov Telescope Array (CTA) composed of more than 100 Cherenkov telescopes. For the first time in this energy domain, CTA will be operated as an observatory open to the astronomy community. In this context, a structured high level data model is being developed to describe a CTA observation. The data model includes different classes of metadata on the project definition, the configuration of the instrument, the ambient conditions, the data acquisition and the data processing. This last part relies on the Provenance Data Model developed within the International Virtual Observatory Alliance (IVOA), for which CTA is one of the main use cases. The CTA data model should also be compatible with the Virtual Observatory (VO) for data diffusion. We have thus developed a web-based data diffusion prototype to test this requirement and ensure the compliance

The Value of High-Frequency Repetitive Transcranial Magnetic Stimulation of the Motor Cortex to Treat Central Pain Sensitization Associated With Knee Osteoarthritis

AimChronic pain associated with knee osteoarthritis may develop in connection with a maladaptive process of pain sensitization in the central nervous system. Repetitive transcranial magnetic stimulation (rTMS) has been proposed to treat various pain syndromes related to central sensitization phenomenon, but was never applied in the context of knee osteoarthritis.MethodsA 71-year-old woman presenting clinical evidence of central sensitization of pain associated with left knee osteoarthritis underwent monthly sessions of rTMS delivered at 10 Hz over the right motor cortex.ResultsFrom the week following the third session, she began to improve on various clinical aspects, including pain. After 10 sessions (i.e., almost one year of follow-up), pain was reduced by 67%, especially regarding neuropathic components, while sleep disorders and fatigue also improved by 57–67%. The central sensitization inventory (CSI) score was reduced by 70%.ConclusionThis observation suggests that high-frequency motor cortex rTMS could be a therapeutic option to treat neuropathic pain and psychological symptoms associated with central sensitization developing in the context of chronic osteoarthritis of the knee joint

Long-Term Relief of Painful Bladder Syndrome by High-Intensity, Low-Frequency Repetitive Transcranial Magnetic Stimulation of the Right and Left Dorsolateral Prefrontal Cortices

Aim: To show the value of low-frequency repetitive transcranial magnetic stimulation (rTMS) of the dorsolateral prefrontal cortex (DLPFC) to treat bladder pain syndrome (BPS), characterized by suprapubic pain, urgency and increased micturition frequency.Methods: A 68-year-old woman with BPS underwent 16 sessions of high-intensity, low-frequency (1 Hz) rTMS of the DLPFC, first on the right hemisphere (one daily session for 5 days, followed by one weekly session for 5 weeks), and then on the left hemisphere (one monthly session for 6 months).Results: At the end of the rTMS protocol, suprapubic pain completely vanished, micturition frequency dramatically decreased (by 60–80%), while fatigue and sleep quality improved (by 57–60%). The patient reported an overall satisfaction rate of 80% and her activities of daily living tending to normalize.Conclusion: This is the first report showing that high-intensity, low-frequency rTMS delivered on the DLPFC region of both hemispheres can relieve most symptoms of BPS (pain, urinary symptoms, and interference with physical functioning) in clinical practice

Gammapy: A Python package for gamma-ray astronomy

In this article, we present Gammapy, an open-source Python package for the analysis of astronomical $\gamma$-ray data, and illustrate the functionalities of its first long-term-support release, version 1.0. Built on the modern Python scientific ecosystem, Gammapy provides a uniform platform for reducing and modeling data from different $\gamma$-ray instruments for many analysis scenarios. Gammapy complies with several well-established data conventions in high-energy astrophysics, providing serialized data products that are interoperable with other software packages. Starting from event lists and instrument response functions, Gammapy provides functionalities to reduce these data by binning them in energy and sky coordinates. Several techniques for background estimation are implemented in the package to handle the residual hadronic background affecting $\gamma$-ray instruments. After the data are binned, the flux and morphology of one or more $\gamma$-ray sources can be estimated using Poisson maximum likelihood fitting and assuming a variety of spectral, temporal, and spatial models. Estimation of flux points, likelihood profiles, and light curves is also supported. After describing the structure of the package, we show, using publicly available $\gamma$-ray data, the capabilities of Gammapy in multiple traditional and novel $\gamma$-ray analysis scenarios, such as spectral and spectro-morphological modeling and estimations of a spectral energy distribution and a light curve. Its flexibility and power are displayed in a final multi-instrument example, where datasets from different instruments, at different stages of data reduction, are simultaneously fitted with an astrophysical flux model.Comment: 26 pages, 16 figure

Astronomie gamma depuis le sol et l’espace : premières analyses du réseau hybride HESS-II et recherche de candidats blazars parmi les sources non-identifiées du Fermi-LAT

This manuscript is about high energy gamma-ray astronomy (between ~30 MeV and ~300 GeV) with the Fermi-LAT satellite and very high energy gamma-ray astronomy (above ~100GeV) via the H.E.S.S. experiment. The second phase of the H.E.S.S. experiment began in July 2012 with the inauguration of a fifth 28m-diameter telescope added to the intial array composed of four 12m-diameter imaging atmospheric Cherenkov telescopes. In the first part of this thesis, we present the development of an analysis in hybrid mode based on a multivariate method dedicated to detect and study sources with different spectral shapes and the first analysis results on real data. The second part is dedicated to the research of blazar candidates among the Fermi-LAT unidentified sources of the 2FGL catalog. A first development is based on a multivariate approach using discriminant parameters built with the 2FGL catalog parameters. A second development is done with the use of the WISE satellite catalog and a non-parametric technic in order to find the blazar-like infrared counterparts of the unidentified sources of the 2FGL catalog.Ce manuscrit traite d'astronomie gamma de haute énergie (entre ~30 MeV et ~300 GeV) par l'intermédiaire du satellite Fermi-LAT et d'astronomie gamma de très haute énergie (au-delà de ~100 GeV) via l'expérience H.E.S.S. La seconde phase de l'expérience H.E.S.S. a débuté en juillet 2012 avec l'ajout d'un cinquième télescope de 28 mètres de diamètre au réseau initialement constitué de quatre télescopes de 12 mètres de diamètre d'imagerie atmosphérique Tcherenkov. Dans la première partie de cette thèse, nous présentons le développement d'une analyse en mode hybride basée sur une méthode multivariée dédiée à la détection et à l'étude de sources ayant des caractéristiques spectrales différentes ainsi que les premiers résultats des analyses de données réelles. La seconde partie est dédiée à la recherche des candidats blazars parmi les sources non identifiées du Fermi-LAT du catalogue 2FGL. Un premier travail est consacré à l'identification des candidats blazars à l'aide de méthodes multivariées utilisant des variables discriminantes construites à partir des paramètres du catalogue 2FGL. Dans un second temps, à l'aide du catalogue de sources infrarouges obtenues par le satellite WISE et d'une méthode non-paramétrique nous recherchons les contreparties de type blazars des sources non-identifiées

Research and characterisation of blazar candidates in the Fermi/LAT 3FGL catalogue using multivariate classifications

International audienceIn the recently published 3FGL catalogue, the Fermi/LAT collaboration reports the detection of γ-ray emission from 3034 sources obtained after 4 years of observations. The nature of 1010 of those sources is unknown, whereas 2023 have counter-parts well identified in other wavelengths. Most of the associated sources are quoted as blazars (1717/2023), but the BL Lac or FSRQ nature of 573 of these blazars is still undetermined. The aim of this study is two-fold. First, to significantly increase the number of blazar candidates from a search among the high number of Fermi/LAT 3FGL unassociated sources. Second, to determine the BL Lac or FSRQ nature of the blazar candidates, including those determined as such in this work and the blazar candidates of uncertain type (BCU) already present in the 3FGL catalogue. For this purpose, multivariate classifiers –boosted decision trees and multilayer perceptron neural networks– are trained on the basis of carefully chosen discriminant parameters. The decisions of these classifiers have been combined in order to obtain high source identification efficiencies along with well controlled rates of fake associations. From this work we obtain a sample of 538 blazar candidates among the 1010 unassociated sources of the 3FGL catalogue. We obtain also a sample of 490 BL Lac and 270 FSRQs both from our 538 blazar candidates and from the sample of 573 BCUs of the 3FGL catalogue. All list of candidates are available at https://unidgamma.in2p3.fr in FITS format

Research and characterisation of blazar candidates among the Fermi/LAT 3FGL catalogue using multivariate classifications

International audienceContext. In the recently published 3FGL catalogue, the Fermi/LAT collaboration reports the detection of γ-ray emission from 3034 sources obtained after four years of observations. The nature of 1010 of those sources is unknown, whereas 2023 have well-identified counterparts in other wavelengths. Most of the associated sources are labelled as blazars (1717/2023), but the BL Lac or FSRQ nature of 573 of these blazars is still undetermined.Aims. The aim of this study was two-fold. First, to significantly increase the number of blazar candidates from a search among the large number of Fermi/LAT 3FGL unassociated sources (case A). Second, to determine the BL Lac or FSRQ nature of the blazar candidates, including those determined as such in this work and the blazar candidates of uncertain type (BCU) that are already present in the 3FGL catalogue (case B).Methods. For this purpose, multivariate classifiers – boosted decision trees and multilayer perceptron neural networks – were trained using samples of labelled sources with no caution flag from the 3FGL catalogue and carefully chosen discriminant parameters. The decisions of the classifiers were combined in order to obtain a high level of source identification along with well controlled numbers of expected false associations. Specifically for case A, dedicated classifications were generated for high (| b | > 10°) and low (| b | ≤ 10°) galactic latitude sources; in addition, the application of classifiers to samples of sources with caution flag was considered separately, and specific performance metrics were estimated. Results. We obtained a sample of 595 blazar candidates (high and low galactic latitude) among the unassociated sources of the 3FGL catalogue. We also obtained a sample of 509 BL Lacs and 295 FSRQs from the blazar candidates cited above and the BCUs of the 3FGL catalogue. The number of expected false associations is given for different samples of candidates. It is, in particular, notably low (~9/425) for the sample of high-latitude blazar candidates from case A.Key words: gamma rays: galaxies / galaxies: active / BL Lacertae objects: general / methods: statistical / catalogs⋆ Full Tables 5 and 7 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/602/A8

Blazars identification among the unidentified sources of the 3FGL gamma-ray catalog

International audienc

Structuring metadata for the Cherenkov Telescope Array

International audienceThe landscape of ground-based gamma-ray astronomy is changing drastically with the perspective of the Cherenkov Telescope Array (CTA) composed of more than 100 Cherenkov telescopes. For the first time in this energy domain, CTA will be operated as an observatory open to the astronomy community. In this context, a structured high level data model is being developed to describe a CTA observation. The data model includes different classes of metadata on the project definition, the configuration of the instrument, the ambient conditions, the data acquisition and the data processing. This last part relies on the Provenance Data Model developed within the International Virtual Observatory Alliance (IVOA), for which CTA is one of the main use cases. The CTA data model should also be compatible with the Virtual Observatory (VO) for data diffusion. We have thus developed a web-based data diffusion prototype to test this requirement and ensure the compliance