Sökning: "SNe"

Visar resultat 1 - 5 av 24 avhandlingar innehållade ordet SNe.

1. 1. Looking for the high-mass progenitors of stripped-envelope supernovae

   Författare :Emir Karamehmetoglu; Jesper Sollerman; Francesco Taddia; Punam Chandra; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Supernova; Supernovae; Stripped-envelope supernovae; SN Type Ibc; SN; SNe; SN progenitor; Type Ibn; Astronomy; astronomi;

   Sammanfattning : Stripped-envelope supernovae were thought to be the explosions of very massive stars (& 20 M) that lost their outer layers of hydrogen and/or helium in strong stellar winds. However, recent studies have highlighted that most stripped-envelope supernovae seem to be arising from rela- tively lower-mass progenitor stars in the 12 20 M(sun) range, creating a mystery about the fate of the higher-mass stars. LÄS MER

3. 2. Self-supervised deep learning and EEG categorization

   Författare :Mats Svantesson; Magnus Thordstein; Håkan Olausson; Anders Eklund; Gerald Cooray; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; EEG; Deep Learning; Self-supervised; Interrater Agreement; T- SNE;

   Sammanfattning : Deep learning has the potential to be used to improve and streamline EEG analysis. At the present, classifiers and supervised learning dominate the field. Supervised learning depends on target labels which most often are created by human experts manually classifying data. LÄS MER

4. 3. Supernova surroundings on circumstellar and galactic scales

   Författare :Anders Nyholm; Jesper Sollerman; Peter Lundqvist; Philip James; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; supernovae; circumstellar medium; SNe Type IIn; iPTF13z; intermediate Palomar Transient Factory; active galactic nuclei; SN 2014J; Astronomy; astronomi;

   Sammanfattning : Some stars cease to be in a bright and destructive display called a supernova. This thesis explores what we can learn about supernovae (SNe) by studying their immediate surroundings, and what the SNe can teach us about their environments. LÄS MER

5. 4. Observations of rare supernovae and their environments

   Författare :Francesco Taddia; Jesper Sollerman; Maryam Modjaz; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Supernova; stellar evolution; metallicity; circumstellar interaction; Astronomy; astronomi;

   Sammanfattning : Supernovae (SNe) are the final stage in the life of massive stars. Their explosion unbinds the progenitor star revealing its inner layers. The SN ejecta interact with the circumstellar material (CSM), providing further information on the progenitor star. LÄS MER

7. 5. Sources of Dust Extinction in Type Ia Supernovae : Measurements and constraints from X-rays to the Infrared

   Författare :Joel Johansson; Edvard Mörtsell; Ariel Goobar; Rahman Amanullah; Bruno Leibundgut; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; supernovae; interstellar dust; circumstellar dust; cosmology; fysik; Physics;

   Sammanfattning : The use of Type Ia supernovae (SNe Ia) as distance indicators is essential for studying the expansion history of the Universe and for exploring the nature of dark energy. However, a lack of understanding of the progenitor systems and the empirically derived colour-brightness corrections represent severe limitations for SNe Ia as cosmological probes. LÄS MER