<p>Syftet med detta examensarbete är att ta reda på hur elevers uppfattningar om de rörelser som sker i vårt solsystem stämmer överens med de vetenskapliga fakta som finns. I våra vardagliga situationer refererar vi till det vi med ögats hjälp kan uppfatta i fråga om vad som rör sig eller ej. Hur påverkas eleverna av de dagliga uttryck som de får höra sedan de är mycket små, och har de en möjlighet att med skolans hjälp förändra dessa tankesätt?</p><p>Undersökningen genomfördes med hjälp av kvalitativa intervjuer av elever i skolår 1 respektive 5. Detta för att se hur stor skillnaden är mellan de elever som inte har erhållit någon undervisning om solsystemet och de elever som ska ha uppnått de mål för fysik som skolverket har ställt upp.</p><p>Eleverna som deltog i studien valdes slumpmässigt ur respektive klasser. De fick besvara 14 frågor, var och en för sig. De besvarade frågorna olika utförligt, vissa var mycket fåordiga. Ibland var jag tvungen att ställa följdfrågor, eftersom jag ville förstå eleverna på ett bra sätt.</p><p>Resultatet av undersökningen visar att elevernas kunskaper inom området har en stor variation, även inom samma åldrar. Detta kan härledas till elevernas eget intresse av vårt solsystem. Den slutsats som jag har dragit av undersökningen är att det är viktigt att ta reda på vilka föreställningar som eleverna har inför arbetet med arbetsområdet.</p> / <p>The purpose of this degree project is to find pupils´ understanding about the movements which occur in our solar system and compare them with the scientific facts we know about. In our daily life we refer to what we can see with the help from our eyes whether something moves or not. How do the pupils´ get affected by these daily expressions they hear from early ages, and do they have an opportunity with the help from the school to change these ways of thinking?</p><p>The survey was carried out with help of qualitative interviews of pupils´ in class 1 and 5. This because to see how large the difference is between pupils´ who hasn’t received any education about the solar system and the pupils´ who are supposed to have reached the goals compiled by The National Agency for Education.</p><p>The pupils´ who took part in this study were chosen by random from both classes. They answered to 14 questions, each and everyone on their own. They answered the questions with various details, some were very taciturn. Sometimes I had to ask resulting questions, since I wanted to understand the pupils´ properly.</p><p>The result of the survey shows that the pupils´ knowledge within the area have a large variation, even within the same ages. This can be deduced to the interest of the pupils´ in our solar system. The conclusion I have maid from this survey are that it is important to find out which understandings the pupils´ have before the work with the subject area.</p>

There exists many astronomical objects that vary in brightness. Objects such as variable stars like the Cepheids that periodically expands and contracts their outer layers, or the active galactic nuclei (AGN) where accretion of matter into a black hole generates a often varying brightness. Several candidates for being such variable objects have been identified as a result of the Vanishing and Appearing Stuff during a Century of Observations (VASCO) project. These candidates were then narrowed down to a handful that showed variability towards the infrared part of the spectrum. This bachelor’s thesis then aims to look further into these candidates using various databases and catalogues taking data from several sky surveys (SDSS, 2MASS etc). This is done to get better overview of the objects lightcurve over a bigger part of the spectrum, to establish whether the variability is real or a result from errors and to form a hypothesis of what kind of objects they could be. The result obtained from the data from the surveys points towards all the objects being real variable objects. The hypothesis is that all the objects are AGN’s that vary in brightness. / Det existerar många olika astronomiska objekt som varierar i ljusstyrka. Allt från variabla stjärnor som Cepheiderna som periodvis expanderar och kontraherar dess yttre skikt, till aktiva galaxkärnor där ackretion av materia in i ett svart hål genererar en ofta varierande ljusstyrka. Ett flertal kandidater för just sådana varierande objekt har identifierats som ett resultat av VASCO projektet. Dessa kandidater har sedan skalats ner till en handfull mängd kandidater som visade variation mot den infraröda delen av spektrumet. Detta kandidatarbete siktar på att vidare undersöka dessa kandidater genom att använda diverse astronomiska databaser och kataloger för att få data från flera kartläggningsprojekt (t.ex. SDSS, 2MASS etc). Detta är gjort för att få en bättre överblick över objektens ljuskurvor över en större del av spektrumet, att fastställa ifall objekten är riktiga variabla objekt eller uppstått på grund av diverse fel, samt att framställa en hypotes för vad det är för typ av objekt de kan vara. Resultaten från undersökningarna pekar på att alla objekten är riktiga variabla objekt. Hypotesen är att alla av objekten är aktiva galaxkärnor som varierar i ljusstyrka.

Asymptotic Giant Branch (AGB) stars are stars with low- to intermediate mass in a late stage in their stellar evolution. An important feature of stellar evolution is the ongoing nucleosynthesis, the creation of heavier elements. Unlike main sequence stars, the AGB stars have a thick convective envelope which makes it possible to dredge-up the heavier fused elements from the stellar core to its surface. AGB stars are also pulsating variable stars, meaning the interior expands and contracts, causing the brightness to fluctuate. These pulsations will also play a major role in the mass loss observed in these stars. The mass loss is caused by stellar winds that accelerate gas and dust from the surface of these stars and thereby chemical enrich the interstellar medium. It is important to understand the properties of these pulsations since they play a key role in how stellar winds are produced and then enrich the galaxy with heavier synthesized elements. These pulsation periods can be observed with their corresponding Light-Curves, where the periodic motion of the brightness can be clearly seen. The main goal with this project is to calculate these pulsation periods for different AGB stars and compare these values with the periods listed in the General Catalogue of Variable Stars (GCVS). The comparison between these values gives a better understanding of methods of determining these periods and the uncertainties that follow. / Asymptotiska jättegrenen är en del av slutstadiet för låg- till medelmassiva stjärnor (AGB stjärnor). Ett viktigt kännetecken hos stjärnutvecklingen är den pågående nukleosyntesen, sammanslagningen av tyngre ämnen i stjärnans inre. Till skillnad mot stjärnor på huvudserien har AGB stjärnor ett tjockt konvektivt lager som gör det möjligt att dra upp dessa nybildade ämnen till stjärnans yta. AGB stjärnor är pulserande variabla stjärnor där variationer i stjärnans radie gör att ljusstyrkan varierar. Dessa pulsationer kommer även att spela en viktig roll för den massförlust som observeras hos dessa stjärnor. Massförlusten orsakas av stjärnvindar som accelererar gas och stoft från stjärnans yta och därmed kemiskt berikar det interstellära mediet. Det är viktigt att förstå dessa pulsationer eftersom de är en viktig komponent för hur stjärnvindar uppstår och sedan berikar galaxer med tyngre ämnen. Dessa pulsationsperioder kan studeras genom att observera stjärnornas ljuskurvor, där man tydligt ser det periodiska beteendet hos ljusstyrkan. Det huvudsakliga målet med detta projekt är att beräkna dessa perioder för olika AGB stjärnor och att sedan jämföra dem med värden från General Catalogue of Variable Stars (GCVS). Jämförelsen mellan dessa värden ger en bättre förståelse för metoderna som används för att bestämma dessa perioder och hur osäkra dessa värden är.

Abstract In this report I present a study of possible age gradients in the Green Pea galaxy J145735.13+223201.8 to be able to conclude if there is an extended star forming history in such a galaxy. Data are coming from two different sources, highly resolved images in four different wavelengths of stars in the galaxy, and of nebular gas in a narrow band Ha Balmer line filter, from the Hubble Space Telescope (HST), as well as spectral line information from the Sloan Digital Sky Survey (SDSS). I compare the observations with stellar population models from two different libraries, Yggdrasil and Starburst99. Due to the highly resolved images from HST this is one of the first studies of spatially resolved stellar populations in a Green Pea galaxy. With the help from these spatially resolved images it was possible to study star clumps independently from each other. This would not be possible when using only data from SDSS. In this way it was possible to conclude an age difference between the centre of the galaxy and its outskirts. I found that the galaxy has an age gradient at a confidence level greater than 95%.

Supernovae (SNe) and more specifically Core-Collapsed SNe (CC SNe) are signatures of on-going star formation (SF), and higher star formation rates. In this project, we perform a study of all SNe ever discovered inside a specific type of galaxy: a type-1 Active Galactic Nucleus (AGN1). We calculate the SN detection fraction for CC SNe and thermonuclear SNe in AGN1. In AGN1, inclination of the host galaxy and the radial distance of the SN to the center of the galaxy are displayed. As a second goal, we gather all SNe from the OpenSN catalogue found close to an AGN1, classify them and compare them with the full sample of OpenSN catalogue host galaxies. Results:We found and calculated the SN detection fraction of AGN1s. We found 16 SNe exploding in 13 different AGN1 host galaxies. The CC/Ia SN ratio is ~ 0.78. Comparing by similar morphology, the AGN1-host galaxies with all the host galaxies from OpenSN, we see that the detection fractions are higher in spiral AGN1 hosts than in normal spiral galaxies, but the difference is not significant (~ 0.4\sigma) to be considered.

<p>The information about the chemical compositions of stars is encoded in their spectra. Accurate determinations of these compositions are crucial for our understanding of stellar nucleosynthesis and Galactic chemical evolution. The determination of elemental abundances in stars requires models for the stellar atmospheres and the processes of line formation. Nearly all spectroscopic analyses of late-type stars carried out today are based on one-dimensional (1D), hydrostatic model atmospheres and on the assumption of local thermodynamic equilibrium (LTE). This approach can lead to large systematic errors in the predicted stellar atmospheric structures and line-strengths, and, hence, in the derived stellar abundances. In this thesis, examples of departures from LTE and from hydrostatic equilibrium are explored. The effects of background line opacities (line-blocking) due to atomic lines on the statistical equilibrium of Fe are investigated in late-type stars. Accounting for this line opacity is important at solar metallicity, where line-blocking significantly reduces the rates of radiatively induced ionizations of Fe. On the contrary, the effects of line-blocking in metal-poor stars are insignificant. In metal-poor stars, the dominant uncertainty in the statistical equilibrium of Fe is the treatment of inelastic H+Fe collisions. Substantial departures of Fe abundances from LTE are found at low metallicities: about 0.3 dex with efficient H+Fe collisions and about 0.5 dex without. The impact of three-dimensional (3D) hydrodynamical model atmospheres on line formation in red giant stars is also investigated. Inhomogeneities and correlated velocity fields in 3D models and differences between the mean 3D stratifications and corresponding 1D model atmospheres can significantly affect the predicted line strengths and derived abundances, in particular at very low metallicities. In LTE, the differences between 3D and 1D abundances of C, N, and O derived from CH, NH, and OH weak low-excitation lines are in the range -0.5 dex to -1.0 dex at [Fe/H]=-3. Large negative corrections (about -0.8 dex) are also found in LTE for weak low-excitation neutral Fe lines. We also investigate the impact of 3D hydrodynamical model stellar atmospheres on the determination of elemental abundances in the carbon-rich, hyper iron-poor stars HE 0107-5240 and HE 1327-2326. The lower temperatures of the line-forming regions of the 3D models compared with 1D models cause changes in the predicted spectral line strengths. In particular we find the 3D abundances of C, N, and O to be lower by about -0.8 dex (or more) than estimated from a 1D analysis. The 3D abundance of Fe is decreased but only by -0.2 dex. Departures from LTE for Fe might actually be very large for these stars and dominate over the effects due to granulation.</p>

The information about the chemical compositions of stars is encoded in their spectra. Accurate determinations of these compositions are crucial for our understanding of stellar nucleosynthesis and Galactic chemical evolution. The determination of elemental abundances in stars requires models for the stellar atmospheres and the processes of line formation. Nearly all spectroscopic analyses of late-type stars carried out today are based on one-dimensional (1D), hydrostatic model atmospheres and on the assumption of local thermodynamic equilibrium (LTE). This approach can lead to large systematic errors in the predicted stellar atmospheric structures and line-strengths, and, hence, in the derived stellar abundances. In this thesis, examples of departures from LTE and from hydrostatic equilibrium are explored. The effects of background line opacities (line-blocking) due to atomic lines on the statistical equilibrium of Fe are investigated in late-type stars. Accounting for this line opacity is important at solar metallicity, where line-blocking significantly reduces the rates of radiatively induced ionizations of Fe. On the contrary, the effects of line-blocking in metal-poor stars are insignificant. In metal-poor stars, the dominant uncertainty in the statistical equilibrium of Fe is the treatment of inelastic H+Fe collisions. Substantial departures of Fe abundances from LTE are found at low metallicities: about 0.3 dex with efficient H+Fe collisions and about 0.5 dex without. The impact of three-dimensional (3D) hydrodynamical model atmospheres on line formation in red giant stars is also investigated. Inhomogeneities and correlated velocity fields in 3D models and differences between the mean 3D stratifications and corresponding 1D model atmospheres can significantly affect the predicted line strengths and derived abundances, in particular at very low metallicities. In LTE, the differences between 3D and 1D abundances of C, N, and O derived from CH, NH, and OH weak low-excitation lines are in the range -0.5 dex to -1.0 dex at [Fe/H]=-3. Large negative corrections (about -0.8 dex) are also found in LTE for weak low-excitation neutral Fe lines. We also investigate the impact of 3D hydrodynamical model stellar atmospheres on the determination of elemental abundances in the carbon-rich, hyper iron-poor stars HE 0107-5240 and HE 1327-2326. The lower temperatures of the line-forming regions of the 3D models compared with 1D models cause changes in the predicted spectral line strengths. In particular we find the 3D abundances of C, N, and O to be lower by about -0.8 dex (or more) than estimated from a 1D analysis. The 3D abundance of Fe is decreased but only by -0.2 dex. Departures from LTE for Fe might actually be very large for these stars and dominate over the effects due to granulation.

Syftet med detta examensarbete är att ta reda på hur elevers uppfattningar om de rörelser som sker i vårt solsystem stämmer överens med de vetenskapliga fakta som finns. I våra vardagliga situationer refererar vi till det vi med ögats hjälp kan uppfatta i fråga om vad som rör sig eller ej. Hur påverkas eleverna av de dagliga uttryck som de får höra sedan de är mycket små, och har de en möjlighet att med skolans hjälp förändra dessa tankesätt? Undersökningen genomfördes med hjälp av kvalitativa intervjuer av elever i skolår 1 respektive 5. Detta för att se hur stor skillnaden är mellan de elever som inte har erhållit någon undervisning om solsystemet och de elever som ska ha uppnått de mål för fysik som skolverket har ställt upp. Eleverna som deltog i studien valdes slumpmässigt ur respektive klasser. De fick besvara 14 frågor, var och en för sig. De besvarade frågorna olika utförligt, vissa var mycket fåordiga. Ibland var jag tvungen att ställa följdfrågor, eftersom jag ville förstå eleverna på ett bra sätt. Resultatet av undersökningen visar att elevernas kunskaper inom området har en stor variation, även inom samma åldrar. Detta kan härledas till elevernas eget intresse av vårt solsystem. Den slutsats som jag har dragit av undersökningen är att det är viktigt att ta reda på vilka föreställningar som eleverna har inför arbetet med arbetsområdet. / The purpose of this degree project is to find pupils´ understanding about the movements which occur in our solar system and compare them with the scientific facts we know about. In our daily life we refer to what we can see with the help from our eyes whether something moves or not. How do the pupils´ get affected by these daily expressions they hear from early ages, and do they have an opportunity with the help from the school to change these ways of thinking? The survey was carried out with help of qualitative interviews of pupils´ in class 1 and 5. This because to see how large the difference is between pupils´ who hasn’t received any education about the solar system and the pupils´ who are supposed to have reached the goals compiled by The National Agency for Education. The pupils´ who took part in this study were chosen by random from both classes. They answered to 14 questions, each and everyone on their own. They answered the questions with various details, some were very taciturn. Sometimes I had to ask resulting questions, since I wanted to understand the pupils´ properly. The result of the survey shows that the pupils´ knowledge within the area have a large variation, even within the same ages. This can be deduced to the interest of the pupils´ in our solar system. The conclusion I have maid from this survey are that it is important to find out which understandings the pupils´ have before the work with the subject area.

The optical turbulence, which creates perturbations of the wavefronts coming from the stars, is caused by small-scale fluctuations in the index of refraction of the atmosphere and is a problem for astronomers because it limits the maximum resolution of the ground-based telescopes. One way of identifying the best sites to build astronomical observatories, where the influence of the optical turbulence is as small as possible, is to use the standard meteorological parameters to get a first idea of the potential of a site. In the first part of this thesis the three sites on the Internal Antarctic Plateau that are the most interesting for astronomers (Dome A, Dome C and the South Pole) are investigated using the operational analyses of the ECMWF and a ranking of these three sites is presented. The second part of this thesis focuses on the ability of the mesoscale model Meso-NH to simulate the optical turbulence as well as the wind speed at Mt Graham (AZ, USA). A rich sample of measurements of the vertical distribution of the optical turbulence, the largest sample used in this type of study so far, is used to calibrate the Meso-NH model and to quantify its ability to simulate the optical turbulence. The measurements are distributed over different periods of the year thus making it possible to evaluate the performance of the model in different seasons. Both the vertical distribution of the optical turbulence and the astroclimatic parameters (seeing, wavefront coherence time and isoplanatic angle) are investigated. / Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 708

It is now widely known that most of the large galaxies we observe (e.g. the Milky Way) host in their center a supermassive black hole ($10^{6}-10^{9}$ $M_\odot$). Several relationships between the central black hole mass and the properties of the stars in the central part of the galaxy have been established in the past 3 decades indicating that the central black hole is able to efficiently structure the matter around it due to episodes of accretion of matter onto the black hole. Recent infrared and optical sky surveys have detected supermassive black holes with masses around $10^{8-9}$ $M_\odot$ when the universe was less than a tenth of its current age and current theories have difficulties explaining how such massive objects could have formed over such short timescales. The goal of the present work is to shed light on the properties of a still largely unknown extreme accretion regime, the so called super-Eddington accretion regime. If such accretion regime could be sustained over sufficient timescales, it could play an important role in both the rapid growth of supermassive black holes as well as its co-evolution with its host galaxy. The aim of this work is therefore to apply high resolution spectroscopy to Ultraluminous X-ray sources in order to identify narrow spectral features to derive constrains on the outflows expected from super-Eddington accreting sources using data from the XMM-Newton observatory. For this purpose I developed a framework to analyse low count background dominated spectra that uses a Monte Carlo approach to detect these narrow features. After analysis of the source Holmberg II X-1, I identify 7 unresolved discrete features with a 3$\sigma$ confidence level that can be tentatively identified with ionic species. Furthermore, the instrumental resolution allows us to put upper limits on the broadening of the lines. This findings will allow us to probe the properties of the outflows of the super-Eddington regime and by extending the analysis to other sources we will able to characterize the observational properties of this accretion regime.