10,318 research outputs found
Jet-cloud/star interaction as an interpretation of neutrino outburst from the blazar TXS 0506+056
Recently, a high-energy neutrino event IceCube-170922A in the spatial and
temporal coincidence with the flaring gamma-ray blazar TXS 0506+056 was
reported. A neutrino outburst between September 2014 and March 2015 was
discovered in the same direction by a further investigation of years of
IceCube data, while the blazar is in a quiescent state during the outburst with
a gamma-ray flux only about one-fifth of the neutrino flux. In this letter, we
propose the neutrino outburst originates from the interaction between a
relativistic jet and a dense gas cloud which may be formed via the tidally
disrupted envelope of a red giant being blown by the impact of the jet.
Gamma-ray photons and electron/positron pairs that are produced correspondingly
will induce electromagnetic cascades. Comptonization of the cascade emission
inside the cloud forms an X-ray photon field with Wien distribution. GeV flux
is suppressed due to the absorption by the Comptonized photon field and, as a
result, a hard spectrum above 10 GeV is formed. The gamma-ray spectrum
predicted in our model is consistent with the Fermi-LAT data of TXS 0506+056.Comment: 6 pages, 3 figure
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Association between Temperature and Emergency Room Visits for Cardiorespiratory Diseases, Metabolic Syndrome-Related Diseases, and Accidents in Metropolitan Taipei
Objective: This study evaluated risks of the emergency room visits (ERV) for cerebrovascular diseases, heart diseases, ischemic heart disease, hypertensive diseases, chronic renal failure (CRF), diabetes mellitus (DM), asthma, chronic airway obstruction not elsewhere classified (CAO), and accidents associated with the ambient temperature from 2000 to 2009 in metropolitan Taipei. Methods: The distributed lag non-linear model was used to estimate the cumulative relative risk (RR) and confidence interval (CI) of cause-specific ERV associated with daily temperature from lag 0 to lag 3 after controlling for potential confounders. Results: This study identified that temperatures related to the lowest risk of ERV was 26 °C for cerebrovascular diseases, 18 °C for CRF, DM, and accidents, and 30 °C for hypertensive diseases, asthma, and CAO. These temperatures were used as the reference temperatures to measure RR for the corresponding diseases. A low temperature (14°C) increased the ERV risk for cerebrovascular diseases, hypertensive diseases, and asthma, with respective cumulative 4-day RRs of 1.56 (95% CI: 1.23, 1.97), 1.78 (95% CI: 1.37, 2.34), and 2.93 (95% CI: 1.26, 6.79). The effects were greater on, or after, lag one. At 32°C, the cumulative 4-day RR for ERV was significant for CRF (RR = 2.36; 95% CI: 1.33, 4.19) and accidents (RR = 1.23; 95% CI: 1.14, 1.33) and the highest RR was seen on lag 0 for CRF (RR = 1.69; 95% CI: 1.01, 3.58), DM (RR = 1.69; 95% CI: 1.09, 2.61), and accidents (RR = 1.19; 95% CI: 1.11, 1.27). Conclusions: Higher temperatures are associated with the increased ERV risks for CRF, DM, and accidents and lower temperatures with the increased ERV risks for cerebrovascular diseases, hypertensive diseases, and asthma in the subtropical metropolitan
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