Detection of variable VHE gamma-ray emission from the extra-galactic gamma-ray binary LMC P3

Context. Recently, the high-energy (HE, 0.1-100 GeV) $\gamma$-ray emission from the object LMC P3 in the Large Magellanic Cloud (LMC) has been discovered to be modulated with a 10.3-day period, making it the first extra-galactic $\gamma$-ray binary. Aims. This work aims at the detection of very-high-energy (VHE, >100 GeV) $\gamma$-ray emission and the search for modulation of the VHE signal with the orbital period of the binary system. Methods. LMC P3 has been observed with the High Energy Stereoscopic System (H.E.S.S.); the acceptance-corrected exposure time is 100 h. The data set has been folded with the known orbital period of the system in order to test for variability of the emission. Energy spectra are obtained for the orbit-averaged data set, and for the orbital phase bin around the VHE maximum. Results. VHE $\gamma$-ray emission is detected with a statistical significance of 6.4 $\sigma$. The data clearly show variability which is phase-locked to the orbital period of the system. Periodicity cannot be deduced from the H.E.S.S. data set alone. The orbit-averaged luminosity in the $1-10$ TeV energy range is $(1.4 \pm 0.2) \times 10^{35}$ erg/s. A luminosity of $(5 \pm 1) \times 10^{35}$ erg/s is reached during 20% of the orbit. HE and VHE $\gamma$-ray emissions are anti-correlated. LMC P3 is the most luminous $\gamma$-ray binary known so far.Comment: 5 pages, 3 figures, 1 table, accepted for publication in A&

A deep spectromorphological study of the γ -ray emission surrounding the young massive stellar cluster Westerlund 1

Context. Young massive stellar clusters are extreme environments and potentially provide the means for efficient particle acceleration. Indeed, they are increasingly considered as being responsible for a significant fraction of cosmic rays (CRs) that are accelerated within the Milky Way. Westerlund 1, the most massive known young stellar cluster in our Galaxy, is a prime candidate for studying this hypothesis. While the very-high-energy γ-ray source HESS J1646-458 has been detected in the vicinity of Westerlund 1 in the past, its association could not be firmly identified. Aims. We aim to identify the physical processes responsible for the γ-ray emission around Westerlund 1 and thus to understand the role of massive stellar clusters in the acceleration of Galactic CRs better. Methods. Using 164 h of data recorded with the High Energy Stereoscopic System (H.E.S.S.), we carried out a deep spectromorphological study of the γ-ray emission of HESS J1646-458. We furthermore employed H I and CO observations of the region to infer the presence of gas that could serve as target material for interactions of accelerated CRs. Results. We detected large-scale (~2 diameter) γ-ray emission with a complex morphology, exhibiting a shell-like structure and showing no significant variation with γ-ray energy. The combined energy spectrum of the emission extends to several tens of TeV, and it is uniform across the entire source region. We did not find a clear correlation of the γ-ray emission with gas clouds as identified through H I and CO observations. Conclusions. We conclude that, of the known objects within the region, only Westerlund 1 can explain the majority of the γ-ray emission. Several CR acceleration sites and mechanisms are conceivable and discussed in detail. While it seems clear that Westerlund 1 acts as a powerful particle accelerator, no firm conclusions on the contribution of massive stellar clusters to the flux of Galactic CRs in general can be drawn at this point

A real-time electronic symptom monitoring system for patients after discharge following surgery: a pilot study in cancer-related surgery

Background: Advances in peri-operative care of surgical oncology patients result in shorter hospital stays. Earlier discharge may bring benefits, but complications can occur while patients are recovering at home. Electronic patient-reported outcome (ePRO) systems may enhance remote, real-time symptom monitoring and detection of complications after hospital discharge, thereby improving patient safety and outcomes. Evidence of the effectiveness of ePRO systems in surgical oncology is lacking. This pilot study evaluated the feasibility of a real-time electronic symptom monitoring system for patients after discharge following cancer-related upper gastrointestinal surgery. Methods: A pilot study in two UK hospitals included patients who had undergone cancer-related upper gastrointestinal surgery. Participants completed the ePRO symptom-report at discharge, twice in the first week and weekly post-discharge. Symptom-report completeness, system actions, barriers to using the ePRO system and technical performance were examined. The ePRO surgery system is an online symptom-report that allows clinicians to view patient symptom-reports within hospital electronic health records and was developed as part of the eRAPID project. Clinically derived algorithms provide patients with tailored self-management advice, prompts to contact a clinician or automated clinician alerts depending on symptom severity. Interviews with participants and clinicians determined the acceptability of the ePRO system to support patients and their clinical management during recovery. Results: Ninety-one patients were approached, of which 40 consented to participate (27 male, mean age 64 years). Symptom-report response rates were high (range 63–100%). Of 197 ePRO completions analysed, 76 (39%) triggered self-management advice, 72 (36%) trigged advice to contact a clinician, 9 (5%) triggered a clinician alert and 40 (20%) did not require advice. Participants found the ePRO system reassuring, providing timely information and advice relevant to supporting their recovery. Clinicians regarded the system as a useful adjunct to usual care, by signposting patients to seek appropriate help and enhancing their understanding of patients’ experiences during recovery. Conclusion: Use of the ePRO system for the real-time, remote monitoring of symptoms in patients recovering from cancer-related upper gastrointestinal surgery is feasible and acceptable. A definitive randomised controlled trial is needed to evaluate the impact of the system on patients’ wellbeing after hospital discharge

Preliminary evidence on the uptake, use and benefits of the CONSORT-PRO extension.

PURPOSE: This study assessed the uptake of the CONsolidated Standards of Reporting Trials (CONSORT)-Patient-Reported Outcomes (PRO) statement; determined if use of CONSORT-PRO was associated with more complete reporting of PRO endpoints in randomised controlled trials (RCTs) and identified the extent to which high-impact journals publishing RCTs with PRO endpoints endorse CONSORT-PRO. METHODS: CONSORT-PRO citations were identified by systematically searching Medline, EMBASE and Google from 2013 (year CONSORT-PRO released) to 17 December 2015. RCTs that cited CONSORT-PRO (cases) were compared to a comparable control sample of RCTs in terms of adherence to CONSORT-PRO using t tests. General linear models assessed the relationship between CONSORT-PRO score and key, pre-specified variables. The 100 highest-impact journals that published RCTs with PRO endpoints (2014-2015) were identified via a systematic Medline search. Instructions for authors were reviewed to determine whether journals endorsed CONSORT-PRO. RESULTS: Total CONSORT-PRO scores ranged from 47 to 100% for cases and 25-96% for controls. Cases had significantly higher total CONSORT-PRO scores compared to controls: t = 2.64, p = 0.01. 'Citing CONSORT-PRO', 'journal endorsing CONSORT-PRO' and 'dedicated PRO paper' were significant predictors of higher CONSORT-PRO adherence score: R (2) = 0.48, p < 0.001. 11/100 top-ranked journals endorsed CONSORT-PRO in their instructions to authors, seven of these journals published RCTs included as cases in this study. CONCLUSION: This study demonstrated improved PRO reporting associated with journal endorsement and author use of the CONSORT-PRO extension. Despite growing awareness, more work is needed to promote appropriate use of CONSORT-PRO to improve completeness of reporting; in particular, stronger journal endorsement of CONSORT-PRO

Constraints on the intergalactic magnetic field using Fermi-LAT and H.E.S.S. blazar observations

Magnetic fields in galaxies and galaxy clusters are believed to be the result of the amplification of intergalactic seed fields during the formation of large-scale structures in the universe. However, the origin, strength, and morphology of this intergalactic magnetic field (IGMF) remain unknown. Lower limits on (or indirect detection of) the IGMF can be obtained from observations of high-energy gamma rays from distant blazars. Gamma rays interact with the extragalactic background light to produce electron-positron pairs, which can subsequently initiate electromagnetic cascades. The $\gamma$-ray signature of the cascade depends on the IGMF since it deflects the pairs. Here we report on a new search for this cascade emission using a combined data set from the Fermi Large Area Telescope and the High Energy Stereoscopic System. Using state-of-the-art Monte Carlo predictions for the cascade signal, our results place a lower limit on the IGMF of $B > 7.1\times10^{-16}$ G for a coherence length of 1 Mpc even when blazar duty cycles as short as 10 yr are assumed. This improves on previous lower limits by a factor of 2. For longer duty cycles of $10^4$ ($10^7$) yr, IGMF strengths below $1.8\times10^{-14}$ G ($3.9\times10^{-14}$ G) are excluded, which rules out specific models for IGMF generation in the early universe.Comment: 20 pages, 7 figures, 4 tables. Accepted for publication in ApJ Letters. Auxiliary data is provided in electronic format at https://zenodo.org/record/801431

Deep observations of Kepler's SNR with H.E.S.S.

Kepler’s supernova remnant (SNR) which is produced by the most recent naked-eye supernova in our Galaxy is one of the best studied SNRs, but its gamma-ray detection has eluded us so far. Observations with modern imaging atmospheric Cherenkov telescopes (IACT) have enlarged the knowledge about nearby SNRs with ages younger than 500 years by establishing Cassiopeia A and Tycho’s SNRs as very high energy (VHE) gamma-ray sources and setting a lower limit on the distance to Kepler’s SNR. This SNR is significantly more distant than the other two and expected to be one of the faintest gamma-ray sources within reach of the IACT arrays of this generation. We report strong evidence for a VHE signal from Kepler’s SNR based on deep observations of the High Energy Stereoscopic System (H.E.S.S.) with an exposure of 152 hours, including 122 hours accumulated in 2017-2020. We further discuss implications of this result for cosmic-ray acceleration in young SNRs

Detection of extended TeV emission around the Geminga pulsar with H.E.S.S.

Highly extended gamma-ray emission around the Geminga pulsar was discovered by Milagro and verified by HAWC. Despite many observations with Imaging Atmospheric Cherenkov Telescopes (IACTs), detection of gamma-ray emission on angular scales exceeding the IACT field-of-view has proven challenging. Recent developments in analysis techniques have enabled the detection of significant emission around Geminga in archival data with H.E.S.S.. In 2019, further data on the Geminga region were obtained with an adapted observation strategy. Following the announcement of the detection of significant TeV emission around Geminga in archival data, in this contribution we present the detection in an independent dataset. New analysis results will be presented, and emphasis given to the technical challenges involved in observations of highly extended gamma-ray emission with IACTs

Astronomy outreach in Namibia : H.E.S.S. and beyond

Astronomy plays a major role in the scientific landscape of Namibia. Because of its excellent sky conditions, Namibia is home to ground-based observatories like the High Energy Spectroscopic System (H.E.S.S.), in operation since 2002. Located near the Gamsberg mountain, H.E.S.S. performs groundbreaking science by detecting very-high-energy gamma rays from astronomical objects. The fascinating stories behind many of them are featured regularly in the "Source of the Month", a blog-like format intended for the general public with more than 170 features to date. In addition to other online communication via social media, H.E.S.S. outreach activities have been covered locally, e.g. through 'open days' and guided tours on the site itself. An overview of the H.E.S.S. outreach activities are presented in this contribution, along with discussions relating to the current landscape of astronomy outreach and education in Namibia. There has also been significant activity in the country in recent months, whereby astronomy is being used to further sustainable development via human capacity-building. Finally, as we take into account the future prospects of radio astronomy in the country, momentum for a wider range of astrophysics research is clearly building — this presents a great opportunity for the astronomy community to come together to capitalise on this movement and support astronomy outreach, with the overarching aim to advance sustainable development in Namibia

Detection of new Extreme BL Lac objects with H.E.S.S. and Swift XRT

Extreme high synchrotron peaked blazars (EHBLs) are amongst the most powerful accelerators found in nature. Usually the synchrotron peak frequency of an EHBL is above 10$^{17}$ Hz, i.e., lies in the range of medium to hard X-rays making them ideal sources to study particle acceleration and radiative processes. EHBL objects are commonly observed at energies beyond several TeV, making them powerful probes of gamma-ray absorption in the intergalactic medium. During the last decade, several attempts have been made to increase the number of EHBL detected at TeV energies and probe their spectral characteristics. Here we report new detections of EHBLs in the TeV energy regime, each at a redshift of less than 0.2, by the High Energy Stereoscopic System (H.E.S.S.). Also, we report on X-ray observations of these EHBLs candidates with Swift-XRT. In conjunction with the very high energy observations, this allows us to probe the radiation mechanisms and the underlying particle acceleration processes