5 research outputs found

    Observation of a sudden cessation of a very-high-energy gamma-ray flare in PKS 1510-089 with H.E.S.S. and MAGIC in May 2016

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    The flat spectrum radio quasar (FSRQ) PKS 1510-089 is known for its complex multiwavelength behavior, and is one of only a few FSRQs detected at very high energy (VHE, E >100 GeV) -rays. VHE -ray observations with H.E.S.S. and MAGIC during late May and early June 2016 resulted in the detection of an unprecedented flare, which reveals for the first time VHE -ray intranight variability in this source. While a common variability timescale of 1.5 hr is found, there is a significant deviation near the end of the flare with a timescale of ∼ 20 min marking the cessation of the event. The peak flux is nearly two orders of magnitude above the low-level emission. For the first time, curvature is detected in the VHE -ray spectrum of PKS 1510-089, which is fully explained through absorption by the extragalactic background light. Optical R-band observations with ATOM reveal a counterpart of the -ray flare, even though the detailed flux evolution differs from the VHE lightcurve. Interestingly, a steep flux decrease is observed at the same time as the cessation of the VHE flare. In the high energy (HE, E >100 MeV) -ray band only a moderate flux increase is observed with Fermi-LAT, while the HE -ray spectrum significantly hardens up to a photon index of 1.6. A search for broad-line region (BLR) absorption features in the -ray spectrum indicates that the emission region is located outside of the BLR. Radio VLBI observations reveal a fast moving knot interacting with a standing jet feature around the time of the flare. As the standing feature is located ∼ 50 pc from the black hole, the emission region of the flare may have been located at a significant distance from the black hole. If this correlation is indeed true, VHE rays have been produced far down the jet where turbulent plasma crosses a standing shock.Accepted manuscrip

    Workplace incivility and work outcomes:Cross-cultural comparison between Australian and Singaporean employees

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    Workplace incivility is a common issue experienced by employees around the globe. However, research has found cultural variability in how workplace incivility is perceived and interpreted. Studies have shown that employees from high power distance societies tend to be more accepting of workplace mistreatment than employees from low power distance societies. Adopting Conservation of Resources (COR) theory and national culture as theoretical frameworks, we tested a moderated mediation model that linked the experience of workplace incivility, burnout/exhaustion, job satisfaction and work withdrawal between Australian and Singaporean white‐collar employees. Data were collected through an online survey of 301 Australian and 303 Singaporean employees. Results indicated that workplace incivility contributed to burnout/exhaustion, which in turn predicted employees’ job dissatisfaction and work withdrawal. Specifically, Australians were more negatively affected by workplace incivility than Singaporeans. The findings suggest the need to consider employees’ national culture/ethnicity when examining relationships between mistreatment in different workplaces and the outcomes

    Detection of the Geminga pulsar with MAGIC hints at a power-law tail emission beyond 15 GeV

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    We report the detection of pulsed gamma-ray emission from the Geminga pulsar (PSR J0633+1746) between 15 GeV and 75 GeV. This is the first time a middle-aged pulsar has been detected up to these energies. Observations were carried out with the MAGIC telescopes between 2017 and 2019 using the low-energy threshold Sum-Trigger-II system. After quality selection cuts, 3c80 h of observational data were used for this analysis. To compare with the emission at lower energies below the sensitivity range of MAGIC, 11 years of Fermi-LAT data above 100 MeV were also analysed. From the two pulses per rotation seen by Fermi-LAT, only the second one, P2, is detected in the MAGIC energy range, with a significance of 6.3\u3c3. The spectrum measured by MAGIC is well-represented by a simple power law of spectral index \u393 = 5.62 \ub1 0.54, which smoothly extends the Fermi-LAT spectrum. A joint fit to MAGIC and Fermi-LAT data rules out the existence of a sub-exponential cut-off in the combined energy range at the 3.6\u3c3 significance level. The power-law tail emission detected by MAGIC is interpreted as the transition from curvature radiation to Inverse Compton Scattering of particles accelerated in the northern outer gap
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