Search for dissertations about: "21-cm"

Showing result 1 - 5 of 6 swedish dissertations containing the word 21-cm.

  2. 1. Tomographic study of the 21-cm signal

    Author : Sambit Kumar Giri; Garrelt Mellema; Matthew Hayes; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; dark ages; reionization; first stars – early universe – methods: statistical – radio lines: galaxies – techniques: interferometric – techniques: image processing; Astronomy; astronomi;

    Abstract : The next generation radio telescopes such as the Square Kilometre Array (SKA) will be able to produce images of the redshifted Hi (neutral hydrogen) 21-cm signal from the Epoch of reionization (EoR). In this thesis, we use the simulated tomographic images of the signal and investigate methods to extract and interpret information from those images. READ MORE

  4. 2. Tomographic studies of the 21-cm signal during reionization : Going beyond the power spectrum

    Author : Sambit K. Giri; Garrelt Mellema; Benoît Semelin; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; reionization; non-gaussianity; first stars; image processing; Astronomy; astronomi;

    Abstract : The formation of the first luminous sources in the Universe, such as the first generation of stars and accreting black holes, led to the ionization of hydrogen gas present in the intergalactic medium (IGM). This period in which the Universe transitioned from a cold and neutral state to a predominantly hot and ionized state is known as the Epoch of Reionization (EoR). READ MORE

  5. 3. Understanding the large-scale structure of the the21-cm signal originating from the Epoch of Reionisation

    Author : Ivelin Georgiev; Garrelt Mellema; Jens Jasche; Aurel Schneider; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; reionisation; cosmology; 21-cm; large-scale structure; Astronomy; astronomi;

    Abstract : The first billion years from the beginning of the Universe is the focus of multiple astronomical facilities in the upcoming decade. This unique era is marked by the formation of the first stars and galaxies, which release ionising radiation into the intergalactic medium(IGM). READ MORE

  6. 4. Simulating observational probes of reionization

    Author : Hannes Jensen; Garrelt Mellema; Adam Lidz; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Astronomy; astronomi;

    Abstract : The time in the history of the Universe when the first stars and galaxies formed and ionized the gas in the intergalactic medium is known as the Epoch of Reionization. This transformative time period, which took place within the first billion years after the Big Bang, is still relatively unexplored due to the significant difficulties associated with observing so far back in time. READ MORE

  7. 5. Next Generation Wideband Antenna Arrays for Communications and Radio Astrophysics

    Author : Christos Kolitsidas; Lars Jonsson; Christophe Craeye; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; array figure of merit; fundamental limits; wideband array; wide scan-angle array; strongly coupled asymmetric dipole array; periodic loading; soft Vivaldi array; 21cm Cosmology; Epoch of Reionization; Electrical Engineering; Elektro- och systemteknik;

    Abstract : Wideband, wide-scan antenna arrays are a promising candidate for the future wireless networks and as well as an essential part of experimental radio astrophysics. Understanding the underline physics of the element performance in the array environment is paramount to develop and improve the performance of array systems. READ MORE