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We study the ionized outflows to the North-East of the edge-on spiral galaxy NGC 4945 with the combination of the Fabry-Perot (FP) and long-slit (LS) observations at the South African Large Telescope (SALT). The FP observation was used to analyse Hα emission, introduce first map of ionized outflows (Hα), continuum, kinematic map (the velocity and velocity dispersion) from some H II regions and SNRs to quantify their impact on the surroundings. Different filaments of ionized gas were traced as well as, bubble shape structure could extended from giant H II region (A3), which shows structure as a feedback onto surroundings. The LS observation introduced the physical properties in these areas with more details by tracing Hα and Hβ as recombination lines and ([N II]λλ6549,6583, [S II]λλ6717,6731 as forbidden lines. The diagnostic diagram based on two ratios (Hα/[N II] and Hα/[S II]) was used to determine the type of these regions which eject ionized outflows. The determined electron densities in the selected regions show a range of values between 2 to 860 cm−3, the highest value appears in region that shows properties of SNR. The oxygen and nitrogen abundances were calculated by using N2 and N2S2 indices for H II regions and SNRs. The oxygen abundances are stable within (2 - 6) kpc of the galactocentric distance, while the abundance of nitrogen rises with increasing the galactocentric distance. The correlation between oxygen and nitrogen abundances presents a mild negative with high metallicity.

We present the first spatially resolved map of stellar proper motions within the central (similar to 3.1 x 2.4 kpc) regions of the Small Magellanic Cloud (SMC). The data used for this study encompasses four tiles from the ongoing near-infrared VISTA survey of the Magellanic Clouds system and covers a total contiguous area on the sky of similar to 6.81 deg(2). Proper motions have been calculated independently in two dimensions from the spatial offsets in the K-s filter over time baselines between 22 and 27 months. The reflex motions of approximately 33 000 background galaxies are used to calibrate the stellar motions to an absolute scale. The resulting catalog is composed of more than 690 000 stars which have been selected based on their position in the (J - K-s; K-s) color-magnitude diagram. For the median absolute proper motion of the SMC, we find (mu(alpha) cos(delta), mu(alpha)) = (1.087 +/- 0.192 (sys.) +/- 0.003 (stat.), -1.187 +/- 0.008 (sys.) +/- 0.003 (stat.)) mas yr(-1), consistent with previous studies. Mapping the proper motions as a function of position within the SMC reveals a nonuniform velocity pattern indicative of a tidal feature behind the main body of the SMC and a flow of stars in the south-east moving predominantly along the line-of-sight.

Using the PACS and SPIRE spectrometers on-board the Herschel Space Observatory, we obtained spectra of two red supergiants (RSGs) in the Large Magellanic Cloud (LMC). Multiple rotational CO emission lines (J = 6–5 to 15-14) and 15 H2O lines were detected from IRAS 05280−6910, and one CO line was detected from WOH G64. This is the first time that CO rotational lines have been detected from evolved stars in the LMC. Their CO line intensities are as strong as those of the Galactic RSG, VY CMa. Modelling the CO lines and the spectral energy distribution results in an estimated mass-loss rate for IRAS 05280−6910 of 3 × 10−4 M⊙ yr−1. The model assumes a gas-to-dust ratio and a CO-to-H2 abundance ratio is estimated from the Galactic values scaled by the LMC metallicity ([Fe/H] ∼ −0.3), i.e. that the CO-to-dust ratio is constant for Galactic and LMC metallicities within the uncertainties of the model. The key factor determining the CO line intensities and the mass-loss rate found to be the stellar luminosity.

Aims. In this study we use multi-epoch near-infrared observations from the VISTA survey of the Magellanic Cloud system (VMC) to measure the proper motions of different stellar populations in a tile of 1.5 deg2 in size in the direction of the Galactic globular cluster 47 Tuc. We obtain the proper motion of the cluster itself, of the Small Magellanic Cloud (SMC), and of the field Milky Way stars. Methods. Stars of the three main stellar components are selected according to their spatial distributions and their distributions in colour−magnitude diagrams. Their average coordinate displacement is computed from the difference between multiple Ks-band observations for stars as faint as Ks = 19 mag. Proper motions are derived from the slope of the best-fitting line among ten VMC epochs over a time baseline of ~1 yr. Background galaxies are used to calibrate the absolute astrometric reference frame. Results. The resulting absolute proper motion of 47 Tuc is (μαcos(δ), μδ) = (+7.26 ± 0.03, −1.25 ± 0.03) mas yr-1. This measurement refers to about 35 000 sources distributed between 10′ and 60′ from the cluster centre. For the SMC we obtain (μαcos(δ), μδ) = (+1.16 ± 0.07, −0.81 ± 0.07) mas yr-1 from about 5250 red clump and red giant branch stars. The absolute proper motion of the Milky Way population in the line of sight (l = 305.9, b = −44.9) of this VISTA tile is (μαcos(δ), μδ) = (+10.22 ± 0.14, −1.27 ± 0.12) mas yr-1 and has been calculated from about 4000 sources. Systematic uncertainties associated with the astrometric reference system are 0.18 mas yr-1. Thanks to the proper motion we detect 47 Tuc stars beyond its tidal radius.

The aim of this thesis was to study the evolution of spiral galaxies by quantifying the impact of the ionized outflows in spiral galaxies on the surrounding interstellar medium. This project was based on optical Fabry-P´erot and long-slit observations with the instrument RSS (Robert Stobie Spectrograph) at the 10 m Southern African Large Telescope (SALT). I focussed on two types of nearby spirals, the first of which is a face-on spiral galaxy (NGC 300) in order to study the kinematics of outflows from Hii regions, and their impact on their surroundings as well as the present-day chemical abundances across these areas. I used the CLOUDY model to compare with my results in order to quantify the conditions in these areas. The second object was the Seyfert 2 galaxy NGC 4945, which shows high activity in the centre (AGN and starburst). I studied the physical properties of the ionize dejected material, their kinematics and morphology. I presented a first kinematic map for the central area based on Fabry-P´erot observations of H_ and [N II]. The shapes of emission lines in this area were analysed to estimate the physical conditions in the areas of interest. The final chapter shows preliminary results of an on-going optical and radio survey for a sample of 36 Southern edge-on disc galaxies in order to study the disc−halo interface by tracing extended ionized extraplanar gas. My results from the previous three projects show that the outflows from Hii regions and AGN and/or starburst play an important role in re-shaping the surrounding ISM by forming filaments or shells. The kinematics of the surrounding gas are affected by the outflows also. My results suggest that the ionized ejected material from the centre of NGC 4945 forms a bi-conal structure, and I constructed a model for the shape of the bi-cone according to my results.

This thesis presents sub-arcsecond resolution observations of massive Young Stellar Objects (YSOs) in two satellite galaxies of the Milky Way, the Magellanic Clouds. With metallicities of »0.5 and »0.2 Z¯ for the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC), respectively the Magellanic Clouds present a unique opportunity to study star formation in environments which differ significantly from those of our own Galaxy.\ud \ud 19 targets in the SMC and 3 targets in the Hii region LHA 120-N113 in the LMC were observed with the near-infrared integral field spectrograph SINFONI at the VLT. Archival SINFONI data towards 7 targets in the Tarantula nebula in the LMC were also obtained. These observations reveal a wide variety of spatially extended emission line morphologies, indicative of outflows and compact Hii regions. Additionally, the most direct indications to date for the presence of discs in massive YSOs in the Magellanic Clouds are presented.\ud \ud Previously obtained optical spectra towards massive YSOs in the SMC have been analysed, as well as newly obtained spectra using the Robert Stobie Spectrograph (RSS) at the Southern African Large Telescope (SALT). Fabry-Perot interferometric observations obtained with RSS at SALT towards two star forming Hii regions in the Magellanic Clouds, are also presented, along with a new Fabry-Perot data reduction pipeline. Through analysis of the optical spectra in the context of the SINFONI data the massive YSOs in the SMC appear to reside in a porous ISM, allowing a large mean-free-path for energetic photons.\ud \ud Through a comparison of massive YSOs in the Magellanic Clouds and a previously obtained Galactic sample, evidence of significantly enhanced accretion rates towards the YSOs in the Magellanic Clouds is detected. Whilst the underlying mechanism of this enhancement is uncertain, there appears to be a convincing correlation between metallicity and accretion rates in massive YSOs.