Sensitivity to point-like sources of the ALTO atmospheric particle detector array, designed for 200 GeV\rm 200\,GeV--50 TeV\rm 50\,TeV γ\gamma-ray astronomy

In the context of atmospheric shower arrays designed for $\gamma$-ray astronomy and in the context of the ALTO project, we present: a study of the impact of heavier nuclei in the cosmic-ray background on the estimated $\gamma$-ray detection performance on the basis of dedicated Monte Carlo simulations, a method to calculate the sensitivity to a point-like source, and finally the required observation times to reach a firm detection on a list of known point-like sources.Comment: 16 pages, 7 figures, accepted for publication in JHEAP (Journal of High-Energy Astrophysics

Variation in Glycemic Outcomes in Focal Forms of Congenital Hyperinsulinism - The UK Perspective

Context: In focal congenital hyperinsulinism (CHI), localized clonal expansion of pancreatic β-cells causes excess insulin secretion and severe hypoglycemia. Surgery is curative, but not all lesions are amenable to surgery. Objective: We describe surgical and nonsurgical outcomes of focal CHI in a national cohort. Methods: Patients with focal CHI were retrospectively reviewed at 2 specialist centers, 2003-2018. Results: Of 59 patients with focal CHI, 57 had heterozygous mutations in ABCC8/KCNJ11 (51 paternally inherited, 6 de novo). Fluorine-18 L-3,4 dihydroxyphenylalanine positron emission tomography computed tomography scan identified focal lesions in 51 patients. In 5 patients, imaging was inconclusive; the diagnosis was established by frozen section histopathology in 3 patients, a lesion was not identified in 1 patient, and 1 declined surgery. Most patients (n = 56) were unresponsive to diazoxide, of whom 33 were unresponsive or partially responsive to somatostatin receptor analog (SSRA) therapy. Fifty-five patients underwent surgery: 40 had immediate resolution of CHI, 10 had persistent hypoglycemia and a focus was not identified on biopsy in 5. In the 10 patients with persistent hypoglycemia, 7 underwent further surgery with resolution in 4 and ongoing hypoglycemia requiring SSRA in 3. Nine (15% of cohort) patients (1 complex surgical access; 4 biopsy negative; 4 declined surgery) were managed conservatively; medication was discontinued in 8 children at a median (range) age 2.4 (1.5-7.7) years and 1 remains on SSRA at 16 years with improved fasting tolerance and reduction in SSRA dose. Conclusion: Despite a unifying genetic basis of disease, we report inherent heterogeneity in focal CHI patients impacting outcomes of both surgical and medical management

Developing a congenital hyperinsulinism prioritized research agenda:a patient-driven international collaborative research network

Introduction: Congenital Hyperinsulinism (HI) is a rare disease that causes severe and recurrent hypoglycemia due to dysregulated insulin secretion. HI is the most frequent cause of severe, persistent hypoglycemia in newborns and children. Disease management is focused on preventing the neurological consequences associated with hypoglycemic brain injury; however, treatment is complex, often suboptimal, and places a large burden on families and individuals living with HI. Congenital Hyperinsulinism International (CHI) is an international patient organization that received a grant from the Chan Zuckerberg Initiative to establish the CHI Collaborative Research Network (CRN), a collaborative body to accelerate research for HI. Assessment process: Stakeholder groups relevant to HI, including individuals living with HI, families, researchers, clinicians, nurses, and industry partners, were identified to join the CRN and work together to create a prioritized research agenda (PRA) to systematically rank research priorities. CRN members worked across 7 workstream groups through a structured process to brainstorm gaps and corresponding solutions to formalize the HI PRA. Actionable recommendations: A total of 362 gaps were identified across research, infrastructure, knowledge, and funding. All groups identified the need for an HI Natural History Study; therefore, this item was identified as a priority that would automatically be placed on the finalized list. Other top gaps identified in the PRA addressed preventing brain damage and the need to increase awareness and understanding related to the role of early and effective diagnosis in preventing brain damage. Discussion: The formation of the CRN and the development of the PRA have already led to new collaborations, which are fundamental to progress. The PRA process allowed individuals to come to a consensus on the critical needs and to chart short- and long-term approaches to fill the gaps. CRN members continue to meet regularly in working groups focused on special projects to fill gaps identified as high priority by the PRA. Through this active and multidimensional alliance, the CRN is re-imagining the future for people living with HI by improving outcomes through more timely and accurate diagnosis, more effective and less burdensome treatments, more easily obtainable expert care, and better tools to manage HI.</p

H.E.S.S. and Suzaku observations of the Vela X pulsar wind nebula

International audience$Context$. Pulsar wind nebulae (PWNe) represent the most prominent population of Galactic very-high-energy gamma-ray sources and are thought to be an efficient source of leptonic cosmic rays. Vela X is a nearby middle-aged PWN, which shows bright X-ray and TeV gamma-ray emission towards an elongated structure called the cocoon. $Aims$. Since TeV emission is likely inverse-Compton emission of electrons, predominantly from interactions with the cosmic microwave background, while X-ray emission is synchrotron radiation of the same electrons, we aim to derive the properties of the relativistic particles and of magnetic fields with minimal modelling. $Methods$. We used data from the $Suzaku$ XIS to derive the spectra from three compact regions in Vela X covering distances from 0.3 to 4 pc from the pulsar along the cocoon. We obtained gamma-ray spectra of the same regions from H.E.S.S. observations and fitted a radiative model to the multi-wavelength spectra. $Results$. The TeV electron spectra and magnetic field strengths are consistent within the uncertainties for the three regions, with energy densities of the order 10$^{−12}$ erg cm$^{−3}$. The data indicate the presence of a cutoff in the electron spectrum at energies of $\sim$100 TeV and a magnetic field strength of $\sim$6 $\mu$G. Constraints on the presence of turbulent magnetic fields are weak. $Conclusions$. The pressure of TeV electrons and magnetic fields in the cocoon is dynamically negligible, requiring the presence of another dominant pressure component to balance the pulsar wind at the termination shock. Sub-TeV electrons cannot completely account for the missing pressure, which may be provided either by relativistic ions or from mixing of the ejecta with the pulsar wind. The electron spectra are consistent with expectations from transport scenarios dominated either by advection via the reverse shock or by diffusion, but for the latter the role of radiative losses near the termination shock needs to be further investigated in the light of the measured cutoff energies. Constraints on turbulent magnetic fields and the shape of the electron cutoff can be improved by spectral measurements in the energy range ≳ 10 keV

H.E.S.S. follow-up of BBH merger events

We present here, follow-up observations of four Binary black hole BBH eventsperformed with the High Energy Stereoscopic System (H.E.S.S.) in the Very HighEnergy (VHE) gamma-ray domain during the second and third LIGO/Virgoobservation runs. Detailed analyses of the obtained data did not showsignificant VHE emission. We derive integral upper limit maps considering ageneric $E^{-2}$ source spectrum in the most sensitive H.E.S.S energy intervalranging from 1 to 10 TeV. We also consider Extragalactic Background Lightabsorption effects and derive integral upper limits over the full accessibleenergy range. We finally derive upper limits of the VHE luminosity for eachevent and compare them with the expected VHE emission from GRBs. Thesecomparisons allow us to assess the H.E.S.S. gravitational wave follow-upstrategies. For the fourth GW observing run O4, we do not expect tofundamentally alter our observing strategy, and will continue to prioritize skycoverage like for the previous runs<br

Science verification of the new FlashCam-based camera in the 28m telescope of H.E.S.S

In October 2019 the central 28m telescope of the H.E.S.S. experiment has been upgraded with a new camera. The camera is based on the FlashCam design which has been developed in view of a possible future implementation in the medium-sized telescopes of the Cherenkov Telescope Array (CTA). We report here on the results of the science verification program that has been performed after commissioning of the new camera, to show that the camera and software pipelines are working up to expectations