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

Refinement of the critical genomic region for congenital hyperinsulinism in the Chromosome 9p deletion syndrome

Version 2; peer review: 3 approved. Available from F1000 Research via the DOI in this recordBackground: Large contiguous gene deletions at the distal end of the short arm of chromosome 9 result in the complex multi-organ condition chromosome 9p deletion syndrome. A range of clinical features can result from these deletions with the most common being facial dysmorphisms and neurological impairment. Congenital hyperinsulinism is a rarely reported feature of the syndrome with the genetic mechanism for the dysregulated insulin secretion being unknown. Methods: We studied the clinical and genetic characteristics of 12 individuals with chromosome 9p deletions who had a history of neonatal hypoglycaemia. Using off-target reads generated from targeted next-generation sequencing of the genes known to cause hyperinsulinaemic hypoglycaemia (n=9), or microarray analysis (n=3), we mapped the minimal shared deleted region on chromosome 9 in this cohort. Targeted sequencing was performed in three patients to search for a recessive mutation unmasked by the deletion. Results: In 10/12 patients with hypoglycaemia, hyperinsulinism was confirmed biochemically. A range of extra-pancreatic features were also reported in these patients consistent with the diagnosis of the Chromosome 9p deletion syndrome. The minimal deleted region was mapped to 7.2 Mb, encompassing 38 protein-coding genes. In silico analysis of these genes highlighted SMARCA2 and RFX3 as potential candidates for the hypoglycaemia. Targeted sequencing performed on three of the patients did not identify a second disease-causing variant within the minimal deleted region. Conclusions: This study identifies 9p deletions as an important cause of hyperinsulinaemic hypoglycaemia and increases the number of cases reported with 9p deletions and hypoglycaemia to 15 making this a more common feature of the syndrome than previously appreciated. Whilst the precise genetic mechanism of the dysregulated insulin secretion could not be determined in these patients, mapping the deletion breakpoints highlighted potential candidate genes for hypoglycaemia within the deleted region.Wellcome TrustRoyal Societ

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

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

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

Revisiting the PeVatron candidate MGRO J1908+06 with an updated H.E.S.S. analysis

Detecting and studying galactic gamma-ray sources emitting very-high energy photons sheds light on the acceleration and propagation of cosmic rays presumably created in these sources. Currently, there are few sources emitting photons with energies exceeding 100 TeV. In this work we revisit the unidentified source MGRO J1908+06, initially detected by Milagro, using an updated H.E.S.S. dataset and analysis pipeline. The vicinity of the source contains a supernova remnant and pulsars as well as molecular clouds. This makes the identification of the primary source(s) of galactic cosmic rays as well as the nature of the gamma-ray emission challenging, especially in light of the recent HAWC and LHAASO detection of the high energy tail of its spectrum. Exploiting the better angular resolution as compared to particle detectors, we investigate the morphology of the source as well as its spectral properties

Evidence of 100 TeV γ-ray emission from HESS J1702-420 : a new PeVatron candidate

The identification of active PeVatrons, hadronic particle accelerators reaching the knee of the cosmic-ray spectrum (at the energy of few PeV), is crucial to understand the origin of cosmic rays in the Galaxy. In this context, we report on new H.E.S.S. observations of the PeVatron candidate HESS J1702-420, which bring evidence for the presence of γ-rays up to 100 TeV. This is the first time in the history of H.E.S.S. that photons with such high energy are observed. Remarkably, the new deep observations allowed the discovery of a new γ-ray source component, called HESS J1702-420A, that was previously hidden under the bulk emission traditionally associated with HESS J1702-420. This new object has a power-law spectral slope < 2 and a γ-ray spectrum that, extending with no sign of curvature up to 100 TeV, makes it an excellent candidate site for the presence of PeV-energy cosmic rays. This discovery brings new information to the ongoing debate on the nature of the unidentified source HESSJ1702-420, and on the origin of Galactic cosmic rays