Publication

Opening the low frequency window to the high redshift Universe

Vedantham, H., 2015, [Groningen]: University of Groningen. 185 p.

Research output: ThesisThesis fully internal (DIV)Academic

APA

Vedantham, H. (2015). Opening the low frequency window to the high redshift Universe. [Groningen]: University of Groningen.

Author

Vedantham, Harish. / Opening the low frequency window to the high redshift Universe. [Groningen] : University of Groningen, 2015. 185 p.

Harvard

Vedantham, H 2015, 'Opening the low frequency window to the high redshift Universe', Doctor of Philosophy, University of Groningen, [Groningen].

Standard

Opening the low frequency window to the high redshift Universe. / Vedantham, Harish.

[Groningen] : University of Groningen, 2015. 185 p.

Research output: ThesisThesis fully internal (DIV)Academic

Vancouver

Vedantham H. Opening the low frequency window to the high redshift Universe. [Groningen]: University of Groningen, 2015. 185 p.


BibTeX

@phdthesis{87cf6d9240a443a28146b44bb603dede,
title = "Opening the low frequency window to the high redshift Universe",
abstract = "The epoch of formation of the first luminous structures (stars and galaxies) called the Comic Dawn, is one of the last unexplored periods in the history of the Universe. A new generation of radio telescopes such as LOFAR aim to revolutionize our understanding of structure formation in the early Universe by directly observing the 21-cm line of hydrogen from this epoch. Due to cosmic expansion, this 21-cm signal reaches us at low radio frequencies (50 to 200 MHz). Properly accounting for and correcting the effects of propagation through an atmospheric layer called the ionosphere is an important outstanding challenge in low frequency observations. In this thesis, I develop a mathematical framework to study ionospheric scintillation (akin to stellar twinkling) and compute its effects on radio observations of the early Universe. I find that although formidable, ionospheric corruptions do not pose a fundamental limit to achieve a detection of the 21-cm signal from the early Universe. In addition, I also demonstrate a new observational technique that uses the Moon as a temperature reference to accurately measure the spectrum of the radio sky. While this technique may in future lead to a detection of the sky-averaged 21-cm signal from the cosmic dawn, I touch upon its potential in the near future to determine lunar crustal composition and temperature at unprecedented depths.",
author = "Harish Vedantham",
year = "2015",
language = "English",
isbn = "978-90-367-7988-3",
publisher = "University of Groningen",
school = "University of Groningen",

}

RIS

TY - THES

T1 - Opening the low frequency window to the high redshift Universe

AU - Vedantham, Harish

PY - 2015

Y1 - 2015

N2 - The epoch of formation of the first luminous structures (stars and galaxies) called the Comic Dawn, is one of the last unexplored periods in the history of the Universe. A new generation of radio telescopes such as LOFAR aim to revolutionize our understanding of structure formation in the early Universe by directly observing the 21-cm line of hydrogen from this epoch. Due to cosmic expansion, this 21-cm signal reaches us at low radio frequencies (50 to 200 MHz). Properly accounting for and correcting the effects of propagation through an atmospheric layer called the ionosphere is an important outstanding challenge in low frequency observations. In this thesis, I develop a mathematical framework to study ionospheric scintillation (akin to stellar twinkling) and compute its effects on radio observations of the early Universe. I find that although formidable, ionospheric corruptions do not pose a fundamental limit to achieve a detection of the 21-cm signal from the early Universe. In addition, I also demonstrate a new observational technique that uses the Moon as a temperature reference to accurately measure the spectrum of the radio sky. While this technique may in future lead to a detection of the sky-averaged 21-cm signal from the cosmic dawn, I touch upon its potential in the near future to determine lunar crustal composition and temperature at unprecedented depths.

AB - The epoch of formation of the first luminous structures (stars and galaxies) called the Comic Dawn, is one of the last unexplored periods in the history of the Universe. A new generation of radio telescopes such as LOFAR aim to revolutionize our understanding of structure formation in the early Universe by directly observing the 21-cm line of hydrogen from this epoch. Due to cosmic expansion, this 21-cm signal reaches us at low radio frequencies (50 to 200 MHz). Properly accounting for and correcting the effects of propagation through an atmospheric layer called the ionosphere is an important outstanding challenge in low frequency observations. In this thesis, I develop a mathematical framework to study ionospheric scintillation (akin to stellar twinkling) and compute its effects on radio observations of the early Universe. I find that although formidable, ionospheric corruptions do not pose a fundamental limit to achieve a detection of the 21-cm signal from the early Universe. In addition, I also demonstrate a new observational technique that uses the Moon as a temperature reference to accurately measure the spectrum of the radio sky. While this technique may in future lead to a detection of the sky-averaged 21-cm signal from the cosmic dawn, I touch upon its potential in the near future to determine lunar crustal composition and temperature at unprecedented depths.

M3 - Thesis fully internal (DIV)

SN - 978-90-367-7988-3

PB - University of Groningen

CY - [Groningen]

ER -

ID: 20633606