Fermi LAT Search for Dark Matter in Gamma-ray Lines and the Inclusive Photon Spectrum

Dark matter particle annihilation or decay can produce monochromatic gamma-ray lines and contribute to the diffuse gamma-ray background. Flux upper limits are presented for gamma-ray spectral lines from 7 to 200 GeV and for the diffuse gamma-ray background from 4.8 GeV to 264 GeV obtained from two years of Fermi Large Area Telescope data integrated over most of the sky. We give cross section upper limits and decay lifetime lower limits for dark matter models that produce gamma-ray lines or contribute to the diffuse spectrum, including models proposed as explanations of the PAMELA and Fermi cosmic-ray data.Comment: Accepted for publication in Physical Review

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

A contribuição dos estudos transculturais dos países latino-americanos e caribenhos para a revisão da CID-10: resultados preliminares The contribution of Latin American and Caribbean countries on culture bound syndromes studies for the ICD-10 revision: key findings from a working in progress

OBJETIVO: Esta revisão visa identificar as evidências dos estudos de países da América Latina e do Caribe para a inclusão das síndromes transculturais na versão da Classificação Internacional de Doenças para sua 11ª Edição. MÉTODO: Os estudos foram identificados nas bases do Medline, LILACS e EMBASE, no período de 1992 a 2008, e classificados segundo o tipo de estudo, tipo de transtorno, país e número de publicações por ano. RESULTADOS: Foram selecionadas e classificadas 163 publicações: 33 no Medline, 90 no EMBASE e 40 no LILACS. A percentagem das síndromes transculturais ("culture bound-syndrome") correspondeu a 9% no Medline, 12% no EMBASE e 2,5% no LILACS. Dos 15 estudos sobre síndromes transculturais, dois eram sobre "nervios e ataque de nervios", dois sobre "susto", quatro sobre a relação entre crenças religiosas, "feitiçaria", transe e apresentação dos transtornos mentais, um sobre proposta de uma nova categoria diagnóstica, três artigos teóricos e três sobre psicopatoplastia dos transtornos mentais. CONCLUSÃO: A escassez de estudos sobre síndromes transculturais pode ter ocorrido pela dificuldade em rastrear os estudos por problema de indexação das publicações, falta de interesse em publicar tais estudos em periódicos indexados e a dificuldade de acesso às publicações. Dentre os estudos identificados, não há uma evidência clara que aponte quais modificações são necessárias nas classificações diagnósticas atuais.<br>OBJECTIVE: This review aims to verify the scientific evidences for the inclusion of culture bound syndromes in the International Classification of Diseases towards its 11th edition based on studies from Latin American and Caribbean countries. METHOD: Studies were identified in Medline, LILACS and EMBASE databases for the period between 1992 and 2008, and then classified according to the type of study, to the mental disorder, country and number of publications per year. RESULTS: 163 studies were selected and classified: 33 in MedlLne, 90 in EMBASE e 40 in LILACS. The percentage of culture bound-syndrome corresponded to 9% in Medline, 12% in EMBASE e 2.5% in LILACS. Among fifteen studies on cultural bound syndromes, two were about "nervios and ataque de nervios", two about "susto", four about the relationship between religion beliefs, witchery, trance and mental disorders, one with a proposal for new diagnostic category, three about theoretic issues and three about the pathoplasty of mental disorders. CONCLUSION: The scarcity of studies on culture bound syndromes might be due to the indexation problems hindering the screening of studies; lack of interest on publishing such studies in indexed journals (publication bias) and due to difficulty to access them. There is no robust evidence identified among cross-cultural studies to recommend changes for International Classification of Diseases-11th edition

Gamma-ray blazar spectra with HESS II mono analysis: The case of PKS2155-304 and PG1553+113

Context. The addition of a 28 m Cherenkov telescope (CT5) to the H.E.S.S. array extended the experiment's sensitivity to lower energies. The lowest energy threshold is obtained using monoscopic analysis of data taken with CT5, providing access to gamma-ray energies below 100 GeV for small zenith angle observations. Such an extension of the instrument's energy range is particularly beneficial for studies of active galactic nuclei with soft spectra, as expected for those at a redshift >= 0.5. The high-frequency peaked BL Lac objects PKS 2155-304 (z = 0.116) and PG 1553 + 113 (0.43 100 GeV interpreted as being due to interactions with the extragalactic background light (EBL). Aims. The aims of this work are twofold: to demonstrate the monoscopic analysis of CT5 data with a low energy threshold, and to obtain accurate measurements of the spectral energy distributions (SED) of PKS 2155-304 and PG 1553 + 113 near their SED peaks at energies approximate to 100 GeV. Methods. Multiple observational campaigns of PKS 2155 304 and PG 1553 + 113 were conducted during 2013 and 2014 using the full H.E.S.S. II instrument (CT1-5). A monoscopic analysis of the data taken with the new CT5 telescope was developed along with an investigation into the systematic uncertainties on the spectral parameters which are derived from this analysis. Results. Using the data from CT5, the energy spectra of PKS 2155 304 and PG 1553 + 113 were reconstructed down to conservative threshold energies of 80 GeV for PKS 2155 304, which transits near zenith, and 110 GeV for the more northern PG 1553 + 113. The measured spectra, well fitted in both cases by a log-parabola spectral model ( with a 5.0 similar to statistical preference for non-zero curvature for PKS 2155 304 and 4.5 sigma for PG 1553+113), were found consistent with spectra derived from contemporaneous Fermi-LAT data, indicating a sharp break in the observed spectra of both sources at E approximate to 100 GeV. When corrected for EBL absorption, the intrinsic H.E.S.S. II mono and Fermi-LAT spectrum of PKS 2155 304 was found to show significant curvature. For PG 1553+113, however, no significant detection of curvature in the intrinsic spectrum could be found within statistical and systematic uncertainties

Multimessenger observations of a flaring blazar coincident with high-energy neutrino IceCube-170922A

Previous detections of individual astrophysical sources of neutrinos are limited to the Sun and the supernova 1987A, whereas the origins of the diffuse flux of high-energy cosmic neutrinos remain unidentified. On 22 September 2017, we detected a high-energy neutrino, IceCube-170922A, with an energy of ~290 tera–electron volts. Its arrival direction was consistent with the location of a known γ-ray blazar, TXS 0506+056, observed to be in a flaring state. An extensive multiwavelength campaign followed, ranging from radio frequencies to γ-rays. These observations characterize the variability and energetics of the blazar and include the detection of TXS 0506+056 in very-high-energy γ-rays. This observation of a neutrino in spatial coincidence with a γ-ray–emitting blazar during an active phase suggests that blazars may be a source of high-energy neutrinos