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 H.E.S.S. 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.Comment: ICRC 2021 conference proceedings, 9 pages, 1 figure, 1 tabl

Search and first detection of very-high-energy photons in gamma-ray bursts: an analysis with HAWC and H.E.S.S.

This thesis is devoted to the study of extremely energetic short-timescale astrophysical events, Gamma-ray bursts (GRBs). GRBs exhibit broad-band bright non-thermal emission, which was analysed using two major experiments: the High Altitude Water Cherenkov observatory (HAWC) and the High Energy Stereoscopic System (H.E.S.S.). The two experiments are in many respects complementary for the observation of very high energy (VHE) gamma-ray emission from GRBs, and in this work the respective advantages were exploited to maximise the sensitivity to VHE signals. After the analysis of several tens of GRBs observed using H.E.S.S. until 2017, where no significant emission was detected, improvements in the observation strategy of H.E.S.S. allowed the detection of GRB~180729B and GRB~190829A. These detections are presented in context with multi-wavelength data, proposing plausible emission mechanisms, thus concluding a decade-long search for these elusive phenomena at VHE. In the second part, novel methods to improve the accuracy of the HAWC detector simulation are presented, including better modelling of the detector efficiencies and electronics. A model that accounts for the detector response and the GRB flux evolution has been developed to estimate the optimal integration time for VHE searches with HAWC. Thanks to these improvements, it is possible to exploit the wide field of view and high duty cycle of HAWC for the search of VHE emission in several tens of GRBs. Preliminary evidence for emission is found in one of the GRBs studied, and upper limits are obtained for all the GRBs analysed and placed in context of the X-ray properties of these events. Finally, the limits and detections presented in this work are placed within the framework of the current understanding of GRBs and prospects for future and present VHE gamma-ray detectors are presented

3-jet events in PbPb collisions

Three jet events in PbPb and pp collisions are studied where jets are clustered by the anti-kt and XCone algorithms. By implementing the pull observable a possible modification of the color connection between the subleading and the third jet is searched, for this, measurement of the angle between the pull vector of the second and third jet is made looking for color connection. In this report due to confidentiality of data, only the results in Monte Carlo simulations is discussed

The case of the missing VHE GRBs: A retrospective study of Swift gamma-ray bursts with Imaging Atmospheric Cherenkov Telescopes

International audienceGamma-ray bursts (GRBs) are particle acceleration sites that can emit photons in the very high-energy (VHE) domain through non-thermal processes. From 2004 until 2018, the current generation of Imaging Atmospheric Cherenkov Telescopes (IACTs) did not detect any GRB in the VHE domain. However, from 2018 to 2020, five detections have been reported. In this work, we try to solve the case of the missing VHE GBRs prior to 2018. We aim to identify GRBs that might have eluded VHE detection in the past years by the H.E.S.S., MAGIC, and VERITAS IACTs. To do so, we study GRBs with known redshift detected by \emph{Swift} from 2004 until June 2022. We first identify all GRBs that could have been observed by these IACTs since 2004, considering observation conditions and visibility constraints. We assume a relation between the X-rays and the VHE gamma rays based on the VHE GRBs detected to date and combine this with the redshift measurements, instrument response information, and observation conditions to predict the observed VHE gamma-ray flux from the \emph{Swift}-XRT measurements. We report findings on 12 bright low-redshift GRBs that we identify as most likely to have been detected in the VHE domain by current IACTs. The rate of IACT-detectable GRBs with ideal observation conditions is $<$1 VHE GRB per year with the current configuration. With its lower energy threshold and higher sensitivity, this rate increases to $\sim$4 VHE GRBs per year with CTA

Susceptibilidad al consumo de tabaco en estudiantes no fumadores de 10 ciudades mexicanas

Objetivo. Identificar la susceptibilidad cognitiva a fumar y los factores asociados en estudiantes de 12 a 15 años. Material y métodos. Se analizó la medición basal de una encuesta autoaplicable en 12 293 estudiantes no fumadores de escuelas secundarias, en el ciclo 2005-2006. Susceptible es aquel que contestó que aceptará un cigarrillo de su mejor amigo y cree que el año próximo fumará. Se obtuvieron modelos de regresión logística de multinivel. Resultados. La prevalencia de susceptibilidad fue de 30%. Los factores asociados fueron autoestima baja (RM = 1.2, IC95% 1.0-1.5), búsqueda de nuevas sensaciones (RM = 1.6, IC95% 1.3-2.0) y actitud favorable a fumar (RM = 2.6, IC95% 2.2-3.2), así como permisividad social reflejada en reglas del hogar (RM = 2.2, IC95% 1.7-2.8). Sólo en mujeres existió interacción entre permisividad de fumar en el hogar y consumo de tabaco en padres (RM = 2.1, IC95% 1.1-3.8). Conclusiones. La prevención debe promover la sensibilización de profesores y padres de familia como modelos antitabaco e incentivar hogares libres de tabaco

Gamma-Ray Burst observation at Very High Energy with H.E.S.S.

International audienceFermi-LAT observations have proven that GeV γ-ray emission is a relatively common feature for many Gamma Ray Bursts (GRB). However the low effective area of space detectors implies low statistics for high energy photons which prevent any physical interpretation at such energy range. The current generation of Imaging Atmospheric Cherenkov Telescopes (IACTs) array of > 104 m2 effective area above a few tens of GeV is able to detect higher energy photons.The High Energy Stereoscopic System (H.E.S.S.) is one of the current generation of IACTs. The large light collection area of the largest telescope and its fast slewing make it perfectly suitable to observe γ rays below 100 GeV with an unprecedented sensitivity. Several tens of GRBs have been observed since 2007. This contribution is about the results of this large sample of observation above a few tens of GeV

Desafíos y tendencias para la perdurabilidad de las organizaciones en escenarios de incertidumbre

This research book contains chapters that analyze the development and strengthening of organizations to become increasingly competitive, facing the opportunities of new business models in the global context. Among the topics discussed are: solutions to problems inherent to the quality of life, productivity, competitiveness, and sustainable development of organizations through innovation, marketing, training, and human talent, among others.Este libro de investigación presenta capítulos que analizan el desarrollo y el fortalecimiento de las organizaciones para hacerse cada vez más competitivas frente a las oportunidades de nuevos modelos de negocios en contextos glocales. Entre los temas presentados se abordan soluciones a problemáticas inherentes a la calidad de vida, la productividad, la competitividad y el desarrollo sostenible de las organizaciones, mediante la innovación, el marketing, la formación y el talento humano, entre otros.Este livro de pesquisa apresenta capítulos que analisam o desenvolvimento e o fortalecimento das organizações para se tornarem cada vez mais competitivas frente às oportunidades de novos modelos de negócios em contextos glocais. Entre os temas apresentados se abordam soluções a problemáticas inerentes à qualidade de vida, a produtividade, a competitividade e o desenvolvimento sustentável das organizações, mediante a inovação, o marketing, a formação e o talento humano, entre outros

The High-Altitude water cherenkov (HAWC) observatory in México: The primary detector

The High-Altitude Water Cherenkov (HAWC) observatory is a second-generation continuously operated, wide field-of-view, TeV gamma-ray observatory. The HAWC observatory and its analysis techniques build on experience of the Milagro experiment in using ground-based water Cherenkov detectors for gamma-ray astronomy. HAWC is located on the Sierra Negra volcano in México at an elevation of 4100 meters above sea level. The completed HAWC observatory principal detector (HAWC) consists of 300 closely spaced water Cherenkov detectors, each equipped with four photomultiplier tubes to provide timing and charge information to reconstruct the extensive air shower energy and arrival direction. The HAWC observatory has been optimized to observe transient and steady emission from sources of gamma rays within an energy range from several hundred GeV to several hundred TeV. However, most of the air showers detected are initiated by cosmic rays, allowing studies of cosmic rays also to be performed. This paper describes the characteristics of the HAWC main array and its hardware.UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Físic

Combined dark matter searches towards dwarf spheroidal galaxies with Fermi-LAT, HAWC, H.E.S.S., MAGIC, and VERITAS

Cosmological and astrophysical observations suggest that 85\% of the total matter of the Universe is made of Dark Matter (DM). However, its nature remains one of the most challenging and fundamental open questions of particle physics. Assuming particle DM, this exotic form of matter cannot consist of Standard Model (SM) particles. Many models have been developed to attempt unraveling the nature of DM such as Weakly Interacting Massive Particles (WIMPs), the most favored particle candidates. WIMP annihilations and decay could produce SM particles which in turn hadronize and decay to give SM secondaries such as high energy $\gamma$ rays. In the framework of indirect DM search, observations of promising targets are used to search for signatures of DM annihilation. Among these, the dwarf spheroidal galaxies (dSphs) are commonly favored owing to their expected high DM content and negligible astrophysical background. In this work, we present the very first combination of 20 dSph observations, performed by the Fermi-LAT, HAWC, H.E.S.S., MAGIC, and VERITAS collaborations in order to maximize the sensitivity of DM searches and improve the current results. We use a joint maximum likelihood approach combining each experiment's individual analysis to derive more constraining upper limits on the WIMP DM self-annihilation cross-section as a function of DM particle mass. We present new DM constraints over the widest mass range ever reported, extending from 5 GeV to 100 TeV thanks to the combination of these five different $\gamma$-ray instruments