Sökning: "Rahman Amanullah"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden Rahman Amanullah.

1. 1. Observations of distant supernovae and cosmological implications

   Författare :Rahman Amanullah; Ariel Goobar; Adam Riess; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; cosmological parameters; cosmology; astro physics; supernovae; type Ia supernova; Cosmology; Kosmologi;

   Sammanfattning : Type Ia supernovae can be used as distance indicators for probing the expansion history of the Universe. The method has proved to be an efficient tool in cosmology and played a decisive role in the discovery of a yet unknown energy form, dark energy, that drives the accelerated expansion of the Universe. LÄS MER

3. 2. The Circumstellar Environment of Type Ia Supernovae

   Författare :Raphael Ferretti; Rahman Amanullah; Ariel Goobar; Josh Simon; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Type Ia supernovae; extinction; supernova cosmology; fysik; Physics;

   Sammanfattning : Type Ia supernovae (SNe Ia) have proven to be extremely useful for measuring cosmological distances and were used for the discovery of the accelerated expansion of the universe. Although thousands of SNe Ia have been observed to date, many questions surrounding the physics of the explosions and the nature of their progenitor systems remain unanswered. LÄS MER

4. 3. 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

5. 4. Search for lensed supernovae behind the galaxy cluster Abell 1689

   Författare :Tanja Petrushevska; Rahman Amanullah; Ariel Goobar; Peter Lundqvist; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; lensed supernovae; gravitational lensing; galaxy cluster Abell 1689; Astronomy; astronomi; fysik; Physics;

   Sammanfattning : Distant supernovae probe the history of cosmic expansion and star formation, and provide important information on their progenitor models. Investigation of supernovae type Ia for  are needed to reveal any evolution in their intrinsic properties, and thus their utility as existing distance indicators. LÄS MER

7. 5. Supernovae seen through gravitational telescopes

   Författare :Tanja Petrushevska; Rahman Amanullah; Ariel Goobar; Saurabh Jha; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; supernovae; strong gravitational lensing; star formation history; supernova rates; supernovor Gravitationslins; fysik; Physics;

   Sammanfattning : Galaxies, and clusters of galaxies, can act as gravitational lenses and magnify the light of objects behind them. The effect enables observations of very distant supernovae, that otherwise would be too faint to be detected by existing telescopes, and allows studies of the frequency and properties of these rare phenomena when the universe was young. LÄS MER