This document describes study of an active star forming region in our galaxy (the Milky Way) known as W22. Physical conditions in these regions can help us in understanding star formation processes in the universe and hence the structure and evolution of the universe. Zeeman effect measurements in 18 cm OH absorption line were carried out in order to estimate the line of sight magnetic field strength in the molecular cloud associated with this star forming region. Other physical parameters such as hydrogen column density, optical depth, critical magnetic field were also determined from these measurements. The region was mapped at 18 cm and the distribution of molecular gas within this star forming complex was described.

A unified theory of star formation remains one of the major unsolved issues in astrophysics. Presented here are the results of multi-molecular lines mapping of the entire giant molecular cloud G333, comprised sites of low- and high-mass star forming regions in various evolution stages of star formation. The result shows the spatial distribution of CS, HCO+, HCN and HNC are similar on large scales, while N2H+ seems to trace preferentially the very densest regions, possibly due to the chemical difference, that N2H+ is sensitive to temperature and readily destroyed by CO. Two analysis methods were used to characterise this large set of data cubes: GAUSSCLUMPS and principal component analysis (PCA). We found the clumps are heavily fragmented with a beam filling factor of ~0.2. We found no correlation between clump radius and line width, contradicts to Larson's Law. Possible explanation is the clumps are fragmented and unresolved with the resolution of Mopra beam, thus the decomposed clump radius is blended and no physical properties can be interpreted. PCA of the velocity dimension found no significant differences among CS, HCO+, HNC and C2H line emissions, suggesting these four molecules are `well-mixed' on large scale, possibly by turbulence. PCA of the integrated emission maps separates molecules into low (13CO and C18O) and high (the rest) density tracers, identifies anti-correlation between HCO+ and N2H+ (due to the depletion of CO). The possibility of removing the scanning patterns of the `on-the-fly' mapping with PCA was also explored. The detection of broad thermal SiO from the massive dense cold core G333.125-0.562, along with other collected transitions, suggesting the core will host massive star formation and the SiO emission arises from shocks associated with an outflow in the cold core. Result of the modelling infall with 3D radiative transfer code using the derived physical parameters have successfully reproduce the line profiles. Recent observation of the 3 and 7 mm continuum emission suggestive of warm dust emission rather than free-free emission from HII, further supports the core is in a very young stage of star formation.

The new CRISP filter at the Swedish 1-m Solar Telescope provides opportunities for observing the solar atmosphere with unprecedented spatial resolution and cadence. In order to benefit from the high quality of observational data from this instrument, we have developed methods for calibrating and restoring polarized Stokes images, obtained at optical and near infrared wavelengths, taking into account field-of-view variations of the filter properties. In order to facilitate velocity measurements, a time series from a 3D hydrodynamical granulation simulation is used to compute quiet Sun spectral line profiles at different heliocentric angles. The synthetic line profiles, with their convective blueshifts, can be used as absolute references for line-of-sight velocities. Observations of the Ca II 8542 Å line are used to study magnetic fields in chromospheric fibrils. The line wings show the granulation pattern at mid-photospheric heights whereas the overlying chromosphere is seen in the core of the line. Using full Stokes data, we have attempted to observationally verify the alignment of chromospheric fibrils with the magnetic field. Our results suggest that in most cases fibrils are aligned along the magnetic field direction, but we also find examples where this is not the case. Detailed interpretation of Stokes data from spectral lines formed in the chromospheric data can be made using non-LTE inversion codes. For the first time, we use a realistic 3D MHD chromospheric simulation of the quiet Sun to assess how well NLTE inversions recover physical quantities from spectropolarimetric observations of Ca II 8542 Å. We demonstrate that inversions provide realistic estimates of depth-averaged quantities in the chromosphere, although high spectral resolution and high sensitivity are needed to measure quiet Sun chromospheric magnetic fields. / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Submitted. Paper 2: Manuscript. Paper 3: Submitted. Paper 4: Submitted.

Transiting planet candidates around rapidly rotating stars, a number of which have been found by the Kepler mission, are not amenable to follow-up via the usual radial velocity techniques due to their rotationally broadened stellar lines. An alternative method is Doppler tomography. In this method, the distortions of the stellar spectral lines due to subtracted light during the transit are spectroscopically resolved. This allows us to not only validate the transiting planet candidate but also to obtain the spin-orbit misalignment for the system. The spin-orbit misalignment is a powerful statistical tracer of the migration histories of planets. I discuss our project to perform Doppler tomographic observations of Kepler candidates and other transiting planets using the facilities at McDonald Observatory. I present our first transit detection, that of Kepler-13 b, and discuss some other recent results. / text

This diploma thesis describes optimization of the experimental parameters for Laser-induced breakdown spectroscopy of plant samples. First part deals with the theoretical method of LIBS and explains the principles and terms. In the next part there is described device which was used for measurements. Main part of diploma thesis describes creation of program for measurement-automation. Main task of program was to solve the connection of autofocus on the sample with the sample automatic movement. Furthermore are described and elaborated specific measurements for optimization of the experimental parameters for Laser-induced breakdown spectroscopy of plant samples.

<p>Opisani&nbsp; su&nbsp; detalji&nbsp; konstrukcije&nbsp; novog&nbsp; izvora&nbsp; plazme, u impulsnom režimu, konstruisanog za&nbsp; potrebe ekscitacija linija berilijuma u&nbsp; prisustvu berilijumske&nbsp; pra&scaron;ine.&nbsp; Konstrukcija&nbsp; izvora&nbsp; je ostvarena&nbsp; na&nbsp; takav&nbsp; način&nbsp; da&nbsp; je&nbsp; sprečeno prodiranje&nbsp; čestica&nbsp; pra&scaron;ine&nbsp; u&nbsp; atmosferu&nbsp; laboratorije.&nbsp; Opisane&nbsp; su&nbsp; dodatne&nbsp; 2&nbsp; cevi&nbsp; za pražnjenje&nbsp; konstruisane&nbsp; od&nbsp; Al2O3 i&nbsp; SiO 2 . Pronađeni&nbsp; su&nbsp; i&nbsp; opisani&nbsp; optimalni&nbsp; uslovi&nbsp; za&nbsp; rad<br />izvora&nbsp; plazme.&nbsp; Vrednosti&nbsp; elektronske&nbsp; koncentracije,&nbsp; određene&nbsp; nakon&nbsp; maksimuma<br />struje,&nbsp; kori&scaron;ćenjem&nbsp; vodonikove&nbsp; balmer&nbsp; beta linije,&nbsp; kreću&nbsp; se&nbsp; u&nbsp; opsegu&nbsp; 1,16-9,2&nbsp; ∙10<br />22&nbsp; m -3 . Elektronska temperatura je određena&nbsp; na&nbsp; osnovu relativnih&nbsp; intenziteta&nbsp; linija&nbsp; dva&nbsp; uzastopna jonizaciona&nbsp; stanja&nbsp; istog&nbsp; elementa&nbsp; i&nbsp; kreće&nbsp; se&nbsp; u opsegu&nbsp; 10&nbsp; 500-15&nbsp; 500&nbsp; K.&nbsp; Prikazane&nbsp; su snimljene&nbsp; linije&nbsp; berilijuma,&nbsp; osim&nbsp; rezonantnih. Dato&nbsp; je&nbsp; poređenje&nbsp; snimljenih&nbsp; linija&nbsp; sa postojećim&nbsp; teorisjkim&nbsp; podacima.&nbsp; Dve&nbsp; linije berilijuma&nbsp; koje&nbsp; se&nbsp; pojavljuju&nbsp; sa&nbsp; zabranjenom komponentom su prikazane prvi put. Pokazano je&nbsp; da&nbsp; postoji&nbsp; tipičan&nbsp; trend&nbsp; zavisnosti&nbsp; odnosa dozvoljene&nbsp; i&nbsp; zabranjene&nbsp; komponente,&nbsp; kao&nbsp; i rastojanja&nbsp; između&nbsp; položaja&nbsp; maksimuma intenziteta ove dve komponente, od elektronske koncentracije,&nbsp; koji&nbsp; se&nbsp; javlja&nbsp; kod&nbsp; linija&nbsp; sa zabranjenim&nbsp; komponentama,&nbsp;&nbsp;&nbsp; &scaron;to&nbsp; govori&nbsp; o<br />mogućnosti ove linije za primenu u dijagnostici plazme.</p> / <p>Construction&nbsp; details&nbsp; of&nbsp; new&nbsp; plasma&nbsp; source,&nbsp; running in pulsed regime,&nbsp; for beryllium spectral line&nbsp; studies,&nbsp; in&nbsp; the&nbsp; presence&nbsp; of&nbsp; beryllium&nbsp; dust particles are presented.&nbsp; The construction of the source&nbsp; was&nbsp; realised&nbsp; in&nbsp; such&nbsp; a&nbsp; way&nbsp; that&nbsp; it prevented&nbsp; the&nbsp; ingress&nbsp; of&nbsp; dust&nbsp; particles&nbsp; into&nbsp; the laboratory&nbsp; atmospher.&nbsp; Construction&nbsp; details&nbsp; and<br />testing&nbsp; of&nbsp; BeO&nbsp; discharge&nbsp; tube&nbsp; in&nbsp; comparison with&nbsp; SiO2 and&nbsp; Al2O3 discharge&nbsp; tubes&nbsp; are&nbsp; presented,&nbsp; also.&nbsp; Optimal&nbsp; conditions&nbsp; for&nbsp; plasma source operation&nbsp; and beryllium line studies are found.&nbsp; The&nbsp; electron&nbsp; density&nbsp; measured&nbsp; after discharge current maximum is determined from&nbsp; the peak separation of the hydrogen Balmer beta<br />spectral&nbsp; line,&nbsp; and&nbsp; the&nbsp; electron&nbsp; temperature&nbsp; is&nbsp; determined&nbsp; from&nbsp; the&nbsp; ratios&nbsp; of&nbsp; the&nbsp; relative&nbsp; intensities&nbsp; of&nbsp; Be&nbsp; spectral&nbsp; lines&nbsp; emitted&nbsp; from successive&nbsp; ionized&nbsp; stages&nbsp; of&nbsp; atoms.&nbsp; Maximum values&nbsp; of&nbsp; electron&nbsp; density&nbsp; and&nbsp; temperature&nbsp; are measured&nbsp; to&nbsp; be&nbsp; 9.3∙1022 m -3 and&nbsp; 16&nbsp; 800&nbsp; K, respectively.&nbsp; The&nbsp; recorded&nbsp; spectral&nbsp; lines&nbsp; of beryllium,&nbsp; other&nbsp; then&nbsp; resonant&nbsp; lines,&nbsp; are&nbsp; presented. The lines&nbsp; with forbidden component are&nbsp; described&nbsp; for&nbsp; the&nbsp; first&nbsp; time.&nbsp; The&nbsp; functional dependence of the wavelength separation range and&nbsp; peak&nbsp; intensity&nbsp; ratio&nbsp; of&nbsp; these&nbsp; lines&nbsp; upon<br />electron&nbsp; number&nbsp; density&nbsp; suggests&nbsp; the&nbsp; complex profile of the forbidden and allowed line, which can be used for diagnostics of low-temperature beryllium containing plasmas.</p>

Dark matter (DM) constitutes one of the most intriguing but so far unresolved issues in physics. In many extensions of the Standard Model of particle physics, the existence of a stable Weakly Interacting Massive Particle (WIMP) is predicted. The WIMP is an excellent DM particle candidate. One of the most interesting scenarios is the creation of monochromatic gamma-rays from the annihilation or decay of these particles. This type of signal would represent a “smoking gun” for DM, since no other known astrophysical process should be able to produce it. In this thesis, the search for spectral lines with the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope (Fermi) is presented. The satellite was successfully launched from Cape Canaveral in Florida, USA, on 11 June, 2008. The energy resolution and performance of the detector are both key factors in the search and are investigated here using beam test data, taken at CERN in 2006 with a scaled-down version of the Fermi-LAT instrument. A variety of statistical methods, based on both hypothesis tests and confidence interval calculations, are then reviewed and tested in terms of their statistical power and coverage. A selection of the statistical methods are further developed into peak finding algorithms and applied to a simulated data set called obssim2, which corresponds to one year of observations with the Fermi-LAT instrument, and to almost one year of Fermi-LAT data in the energy range 20–300 GeV. The analysis on Fermi-LAT data yielded no detection of spectral lines, so limits are placed on the velocity-averaged cross-section, <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?%3C%5Csigma%20v%3E_%7B%5Cgamma%20X%7D" />, and the decay lifetime, <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?%5Ctau_%7B%5Cgamma%20X%7D" />, and theoretical implications are discussed. / QC20100525 / GLAST

This thesis deals with a general overview of laser-induced breakdown spectroscopy - ablation of material and plasma formation when a change of the surrounding environment occurs. The aim is to establish ideal conditions for improving detection, which is difficult for some elements when the measurement takes place in the ambient atmosphere. This is the reason why we change the ambient conditions, the gas (air, helium, argon) and its pressure. Buffer gases (helium, argon) influence the development of the material ablation and quality of generated plasma. That is why we inspect the changes in the signal according to particular atmospheres (signal change in buffer gases compared to the ambient atmosphere). The first part of the thesis presents the principle and physical nature of laser ablation with a brief search of experiments performed so far for similar purposes. Based on this search we determine conclusions about the influence of buffer gasses and pressure on the detection used gasses. In the second part of the work, the controlled experiment is presented, which consisted of the detection of spectral lines of fluorine and potassium, see chapter 5.6 and molecular transitions of calcium fluoride, see chapter 5.10. In a controlled experiment, we established two assumptions. The first assumption is the influence of the inert gas atmosphere, which should significantly improve the detection of fluorine and potassium compared to the air atmosphere. We confirmed this finding only for the argon atmosphere. In contrast, in the helium atmosphere, the detection of none of the elements improved. The second assumption is the effect of reducing the ambient pressure, which in combination with an inert gas should allow the detection of fluorine even at low concentrations in the sample. We consider the measured glass disk in chapter 5.7 to be such a sample. This assumption is not confirmed, as the increased intensity of the fluorine spectral line does not manifest itself in any way when the pressure in the vacuum chamber decreases. Finally, in chapter 7 from the results of individual parts of the experiment, the most suitable conditions for the future detection of the measured substances were proposed: fluorine, potassium and calcium fluoride molecules.