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No description available.

In recent decades, thousands of exoplanets have been discovered. The next step is to characterize theobserved planets in terms of their radii, masses, density, physical conditions and composition of theiratmospheres. Several space-based observatories such as TESS and CHEOPS have started determiningthe first three observables but characterization of exoplanetary atmospheres is waiting for observationcampaigns with instruments like CRIRES+ at the VLT and NIRSpec on the JWST. To ensure the efficiencyof data acquisition, careful planning of observations is necessary. In this project we developeda software tool to select and rank candidates based on the feasibility of observations of atmosphericfeatures during transits with CRIRES+. We also review different techniques to retrieve transmissionspectra from transit observations and modeling of exoplanet atmospheres in order to clarify the requirementsfor the data. Our CRIRES-planning-tool is built on astronomical observation planningmethods from astropy and astroplan and the exposure time calculator designed for CRIRES+ byESO and UU. We conclude that observations for atmospheric characterization with CRIRES+ are feasible.However, we observed that for a robust candidate selection, careful iterative tuning of proposedconstraints is required.

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Denna undersökning har som syfte att bidra till ökad förståelse av astronomiundervisningensplats i den Svenska gymnasieskolan. Huvudmålet med undersökningen har varit att söka svarpå de fyra följande forskningsfrågorna: Vilken plats får astronomin i undervisningen?, Inkluderarlärarna elevernas astronomikunskaper när de sätter slutbetyg i kursen?, Skiljer det sigmycket mellan olika lärares undervisning? och Upplever lärarna några särskilda svårigheter medatt undervisa i astronomi?. Studien har även haft ett bisyfte att genomföra en översättning avdiagnostestet ADT 2.0 från engelska till svenska. Detta för att möjliggöra en användning försvenska gymnasielärare. Som metod valdes en webbaserad enkätstudie att utföras. Totalt settdeltog 23 ämneslärare i fysik, varav 20 deltagande svarade på enkäten och tre respondenterdeltog i förberedande intervjuer. Antalet deltagande är inte tillräckligt för att någon slutsatsska kunna ställas gällande undervisningen i de svenska gymnasieskolorna, men resultatet följer ilinje med tidigare undersökningar. Resultatet indikerar att astronomin får en undanskymd rolldär merparten av deltagarna ägnar 1 till 6 lektioner på området. 52 procent av lärarna vägerinte in elevernas astronomikunskaper i slutbetyget. Gällande lärarnas egna svårigheter med attundervisa astronomi anger 30 procent att de känner sig ha förlite kunskaper inom ämnet. / The purpose of this study is to contribute to the knowledge of the astronomy education inSwedish upper secondary schools. The main goal of the study is to find answers on the followingfour questions: What position is given to the astronomy in Swedish upper secondary education?,Is the students’ knowledge of astronomy accounted for when the teachers are setting the grades?,Does the astronomy teaching vary a lot between different teachers? and Do teachers experienceany difficulties with teaching astronomy? The study has a second goal of translating the AstronomyDiagnostic Test ADT 2.0 from English to Swedish. To collect the data from teachers inSwedish high schools, participating teachers answered a web-based survey. In total, 23 physicsteachers participated in the study, of which 20 teachers completed the survey and 3 teacherswere interviewed. The number of participants is not enough to make a generalising conclusionsabout astronomy education in Swedish upper secondary schools. However the findings are inagreement with previous studies. I found that astronomy gets a small role in the education,where most of the teachers dedicate just 1 to 6 lessons to astronomy. 52 percent of the teachersdo not account for the student knowledge in astronomy when grading the course. When it comesto the teachers own experienced difficulties, 30 percent of the participants specify that they feelthat they have too little knowledge in astronomy.

A small report that investigates neutrino emission from supernovae, in order to estimate at what distance you will have to be from a supernova for the neutrino radiation to kill you.

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This thesis considers emission from gamma-ray bursts (GRBs), the most powerful explosions known in the Universe. Most GRBs are likely associated with the final stages of stellar evolution, where the core of a massive star collapses, and gives birth to a highly compact object such as a neutron star or black hole. The wide energy range of the Fermi Gamma-ray Space Telescope allows for unprecedented studies of GRBs. Fermi data is used to study the emission released at the photosphere of the relativistic outow ejected from the central compact object. The thesis present studies of two of the strongest GRBs ever detected; GRB 090902B (Papers I, II) and GRB 110721A (Paper III). Photospheric emission is identied and its properties are studied for both GRBs. For the first time, observational evidence is found for spectral broadening of photospheric emission. Motivated by these results, possible mechanisms to make the emission from the photosphere appear broader than the Planck spectrum are examined. Two separate theoretical explanations are presented. Apart from the possibility of energy dissipation below the photosphere (Paper II), geometrical effects in outflows with angle dependent properties is shown to significantly broaden the photospheric spectrum (Paper IV). Most importantly, the observed spectrum below the peak energy may become significantly softer inthe latter case. This thesis thus concludes that photospheric emission in GRBs may be more common than previously thought. This is because the emission spectrum from the jet photosphere does not necessarily need to be a Planck function. On the contrary it is shown that broader and/or multicomponent spectra naturally arise, consistent with what is generally observed. In particular, the thesis presents a new mechanism for spectral broadening due to geometrical effects, which must be taken into consideration in the study of GRB emission. / <p>QC 20120907</p>

When high-energy neutrinos interact with matter, radio waves will be emitted. Radio detectionallows us to measure UHE(&gt; 1016eV) neutrinos by instrumenting a huge volume with a sparsearray of radio antenna stations at a low cost. The radio signal measured by the antennas can then beanalyzed to estimate the physics quantity of the corresponding interaction. Traditional reconstructionmethods are time-consuming to develop and often do not account for all information in the signal. Onthe other hand, deep learning-based reconstruction is a powerful technique for radio detector data.Promising results predicting the neutrino energy and direction have been already achieved. However,so far, only the nominal value was predicted, but for the interpretation of data, the event-by-eventuncertainty is crucial and almost as important as the reconstruction of the nominal value. In thisthesis, I added an event-by-event uncertainty prediction of neutrino energy to the deep learningreconstruction using two methods: 1) Likelihood Inference or 2) Normalising Flows. NormalizingFlows allows predicting arbitrary PDFs event-by-event, whereas the first method only predicts astandard deviation per event. The predicted PDFs using Normalising Flows are close to a Gaussian.Hence, both methods can be used interchangeably

HD 140283, also known as the Methuselah star, is an old, metal-poor star on the subgiant branch.It has been the subject of many studies due to its relatively large apparent brightness, and due to itbeing one of the oldest stars known. Accurate age measurements can therefore put limits on the ageof the Universe, and help constrain cosmological models. We present a new investigation of the ageof HD 140283, based on the precise parallax measured by Gaia, PARSEC and BaSTI stellar isochronemodels, and a careful consideration of systematics. We find τ = 13.8 ± 0.5 Gyr, where the error isdominated by the effective temperature uncertainty. This does not imply an obvious tension with thestandard ΛCDM cosmological model (τuniverse = 13.80 ± 0.02 Gyr).