Colors and shapes of light from the Fast Radio Burst 20180916B
Colors and shapes of light from the Fast Radio Burst 20180916B
Dokument öffnen (34.1MB)Art der Hochschulschrift
DissertationPrüfungsdatum
09.03.2026Datum der Veröffentlichung
25.03.2026Erstgutachter
Kramer, MichaelZweitgutachter
Langer, NorbertMetadaten
Zur Langanzeige
Zitierbare Links 
Inhalt
This thesis presents three works that study spectral and polarization properties of emissions from an extragalactic transient source, Fast Radio Burst 20180916B. This source emits bursts of emission, with milliseconds of duration and hundreds of MHz of bandwidth, which have been detected across frequencies ranging from 100 MHz to 6 GHz. The transient source was localized to the outer edge of a quiescent spiral galaxy at a redshift of 0.0337. Observations with the Hubble Space Telescope or with the European VLBI Network did not reveal any persistent source at the FRB location. Although bursts from this source follow Poissonian statistics up to timescales of hours, they reveal a periodic behavior on timescales of days, wherein the bursts detected at 600 MHz only appear in a five-day active window that is periodic with a period of 16.34 days. Several low frequency (≲ 1 GHz) studies showed variations in the active window against observing frequency, such that active windows shift and scale with frequency. Polarimetric studies determined bursts to have high linear polarization fractions, almost no circular polarization fractions, and unchanging orientations (or Position Angle, PA) of the bursts. Continuous polarimetric monitoring also revealed the Rotation Measure (RM) of the bursts to vary in steps, where RM only varies stochastically during certain times and secularly during a specific epoch.
The first work of this thesis studies the variations in the active windows as a function of frequency.
The frequency dependency in periodicity is termed "chromaticity". This work included modeling of the active windows of low-frequency detections of bursts using power law models and testing the model at high frequencies by conducting observations with the 100-meter Effelsberg Radio Telescope at 4-8 GHz in the predicted active windows. The observations led to the first high-frequency detection of bursts from this source. Detection of the bursts confirmed the chromaticity and the burst activity at higher frequencies.
The second work of this thesis involves tracking the RM variations of the bursts detected using upgraded Giant Metrewave Radio Telescope (uGMRT) in 550-750 MHz. First, a versatile polarization calibration pipeline was developed, that can work with different calibration sources. The pipeline was used to polarization calibration all the bursts. Thereafter, an RM measurement strategy was devised, which was used to make all the measurements. The RM measurements corroborated with measurements made using different instruments. Additionally, the sensitivity of uGMRT allowed for a thorough study of burst statistics against their fluences.
The third and final work of this thesis measures and interprets PAs of the bursts detected using uGMRT.
It begins with fitting one RM and one PA to the bursts of an observation and showing that PAs vary less than 7 degrees within four hours. In addition, it reports the PA variations to follow the periodicity of the source, suggesting that PA variations and periodicity have the same cause. It also tentatively reports PA to vary within an active window by few deg hr−1, and from one active window to another at the same phase by 0.1 deg day−1. Notwithstanding, the non-variability of PA is used to set constraints on the source models that explain the long-term periodicity.
If the frequency of light can be perceived as its color, polarization of light can be perceived as its shape.
Therefore, the title of the thesis reads Colors and shapes of light from the Fast Radio Burst 20180916B.
The Chapter 1 of this thesis shows how polarization of light traces an ellipse that has an orientation, an axial ratio, and a sense of rotation. Thereafter, it derives independent and additive parameterization of polarization, proposed by G. G. Stokes and named in his honor, the Stokes parameters. Lastly, the effect of Faraday rotation on the orientation of polarization of light is understood. The Chapter 2 of the thesis describes the phenomena of Fast Radio Bursts. It also describes the process of searching for a Fast Radio Burst, measuring different types of observables from the bursts, and the range of sciences that can be done with the measurements. The Chapter 3 of this thesis focuses solely on Fast Radio Burst 20180916B, which is regarded as the protagonist of this thesis. It contains all the known information about the source in one place. The Chapters 4, 5, and 6 are the science chapters of this thesis, which describe my contributions to the aforementioned three works of this thesis. Lastly, the final Chapter 7 concludes this thesis by describing my aspirations and motivations for my future.
The first work of this thesis studies the variations in the active windows as a function of frequency.
The frequency dependency in periodicity is termed "chromaticity". This work included modeling of the active windows of low-frequency detections of bursts using power law models and testing the model at high frequencies by conducting observations with the 100-meter Effelsberg Radio Telescope at 4-8 GHz in the predicted active windows. The observations led to the first high-frequency detection of bursts from this source. Detection of the bursts confirmed the chromaticity and the burst activity at higher frequencies.
The second work of this thesis involves tracking the RM variations of the bursts detected using upgraded Giant Metrewave Radio Telescope (uGMRT) in 550-750 MHz. First, a versatile polarization calibration pipeline was developed, that can work with different calibration sources. The pipeline was used to polarization calibration all the bursts. Thereafter, an RM measurement strategy was devised, which was used to make all the measurements. The RM measurements corroborated with measurements made using different instruments. Additionally, the sensitivity of uGMRT allowed for a thorough study of burst statistics against their fluences.
The third and final work of this thesis measures and interprets PAs of the bursts detected using uGMRT.
It begins with fitting one RM and one PA to the bursts of an observation and showing that PAs vary less than 7 degrees within four hours. In addition, it reports the PA variations to follow the periodicity of the source, suggesting that PA variations and periodicity have the same cause. It also tentatively reports PA to vary within an active window by few deg hr−1, and from one active window to another at the same phase by 0.1 deg day−1. Notwithstanding, the non-variability of PA is used to set constraints on the source models that explain the long-term periodicity.
If the frequency of light can be perceived as its color, polarization of light can be perceived as its shape.
Therefore, the title of the thesis reads Colors and shapes of light from the Fast Radio Burst 20180916B.
The Chapter 1 of this thesis shows how polarization of light traces an ellipse that has an orientation, an axial ratio, and a sense of rotation. Thereafter, it derives independent and additive parameterization of polarization, proposed by G. G. Stokes and named in his honor, the Stokes parameters. Lastly, the effect of Faraday rotation on the orientation of polarization of light is understood. The Chapter 2 of the thesis describes the phenomena of Fast Radio Bursts. It also describes the process of searching for a Fast Radio Burst, measuring different types of observables from the bursts, and the range of sciences that can be done with the measurements. The Chapter 3 of this thesis focuses solely on Fast Radio Burst 20180916B, which is regarded as the protagonist of this thesis. It contains all the known information about the source in one place. The Chapters 4, 5, and 6 are the science chapters of this thesis, which describe my contributions to the aforementioned three works of this thesis. Lastly, the final Chapter 7 concludes this thesis by describing my aspirations and motivations for my future.
Schlagwörter
Transient, Polarization, Fast Radio Burst
Klassifikation (DDC)
500 Naturwissenschaften 520 Astronomie, KartografieBethapudi, Suryarao: Colors and shapes of light from the Fast Radio Burst 20180916B. - Bonn, 2026. - Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn.
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5-88737
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5-88737
@phdthesis{handle:20.500.11811/14014,
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5-88737,
doi: https://doi.org/10.48565/bonndoc-826,
author = {{Suryarao Bethapudi}},
title = {Colors and shapes of light from the Fast Radio Burst 20180916B},
school = {Rheinische Friedrich-Wilhelms-Universität Bonn},
year = 2026,
month = mar,
note = {This thesis presents three works that study spectral and polarization properties of emissions from an extragalactic transient source, Fast Radio Burst 20180916B. This source emits bursts of emission, with milliseconds of duration and hundreds of MHz of bandwidth, which have been detected across frequencies ranging from 100 MHz to 6 GHz. The transient source was localized to the outer edge of a quiescent spiral galaxy at a redshift of 0.0337. Observations with the Hubble Space Telescope or with the European VLBI Network did not reveal any persistent source at the FRB location. Although bursts from this source follow Poissonian statistics up to timescales of hours, they reveal a periodic behavior on timescales of days, wherein the bursts detected at 600 MHz only appear in a five-day active window that is periodic with a period of 16.34 days. Several low frequency (≲ 1 GHz) studies showed variations in the active window against observing frequency, such that active windows shift and scale with frequency. Polarimetric studies determined bursts to have high linear polarization fractions, almost no circular polarization fractions, and unchanging orientations (or Position Angle, PA) of the bursts. Continuous polarimetric monitoring also revealed the Rotation Measure (RM) of the bursts to vary in steps, where RM only varies stochastically during certain times and secularly during a specific epoch.
The first work of this thesis studies the variations in the active windows as a function of frequency.
The frequency dependency in periodicity is termed "chromaticity". This work included modeling of the active windows of low-frequency detections of bursts using power law models and testing the model at high frequencies by conducting observations with the 100-meter Effelsberg Radio Telescope at 4-8 GHz in the predicted active windows. The observations led to the first high-frequency detection of bursts from this source. Detection of the bursts confirmed the chromaticity and the burst activity at higher frequencies.
The second work of this thesis involves tracking the RM variations of the bursts detected using upgraded Giant Metrewave Radio Telescope (uGMRT) in 550-750 MHz. First, a versatile polarization calibration pipeline was developed, that can work with different calibration sources. The pipeline was used to polarization calibration all the bursts. Thereafter, an RM measurement strategy was devised, which was used to make all the measurements. The RM measurements corroborated with measurements made using different instruments. Additionally, the sensitivity of uGMRT allowed for a thorough study of burst statistics against their fluences.
The third and final work of this thesis measures and interprets PAs of the bursts detected using uGMRT.
It begins with fitting one RM and one PA to the bursts of an observation and showing that PAs vary less than 7 degrees within four hours. In addition, it reports the PA variations to follow the periodicity of the source, suggesting that PA variations and periodicity have the same cause. It also tentatively reports PA to vary within an active window by few deg hr−1, and from one active window to another at the same phase by 0.1 deg day−1. Notwithstanding, the non-variability of PA is used to set constraints on the source models that explain the long-term periodicity.
If the frequency of light can be perceived as its color, polarization of light can be perceived as its shape.
Therefore, the title of the thesis reads Colors and shapes of light from the Fast Radio Burst 20180916B.
The Chapter 1 of this thesis shows how polarization of light traces an ellipse that has an orientation, an axial ratio, and a sense of rotation. Thereafter, it derives independent and additive parameterization of polarization, proposed by G. G. Stokes and named in his honor, the Stokes parameters. Lastly, the effect of Faraday rotation on the orientation of polarization of light is understood. The Chapter 2 of the thesis describes the phenomena of Fast Radio Bursts. It also describes the process of searching for a Fast Radio Burst, measuring different types of observables from the bursts, and the range of sciences that can be done with the measurements. The Chapter 3 of this thesis focuses solely on Fast Radio Burst 20180916B, which is regarded as the protagonist of this thesis. It contains all the known information about the source in one place. The Chapters 4, 5, and 6 are the science chapters of this thesis, which describe my contributions to the aforementioned three works of this thesis. Lastly, the final Chapter 7 concludes this thesis by describing my aspirations and motivations for my future.},
url = {https://hdl.handle.net/20.500.11811/14014}
}
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5-88737,
doi: https://doi.org/10.48565/bonndoc-826,
author = {{Suryarao Bethapudi}},
title = {Colors and shapes of light from the Fast Radio Burst 20180916B},
school = {Rheinische Friedrich-Wilhelms-Universität Bonn},
year = 2026,
month = mar,
note = {This thesis presents three works that study spectral and polarization properties of emissions from an extragalactic transient source, Fast Radio Burst 20180916B. This source emits bursts of emission, with milliseconds of duration and hundreds of MHz of bandwidth, which have been detected across frequencies ranging from 100 MHz to 6 GHz. The transient source was localized to the outer edge of a quiescent spiral galaxy at a redshift of 0.0337. Observations with the Hubble Space Telescope or with the European VLBI Network did not reveal any persistent source at the FRB location. Although bursts from this source follow Poissonian statistics up to timescales of hours, they reveal a periodic behavior on timescales of days, wherein the bursts detected at 600 MHz only appear in a five-day active window that is periodic with a period of 16.34 days. Several low frequency (≲ 1 GHz) studies showed variations in the active window against observing frequency, such that active windows shift and scale with frequency. Polarimetric studies determined bursts to have high linear polarization fractions, almost no circular polarization fractions, and unchanging orientations (or Position Angle, PA) of the bursts. Continuous polarimetric monitoring also revealed the Rotation Measure (RM) of the bursts to vary in steps, where RM only varies stochastically during certain times and secularly during a specific epoch.
The first work of this thesis studies the variations in the active windows as a function of frequency.
The frequency dependency in periodicity is termed "chromaticity". This work included modeling of the active windows of low-frequency detections of bursts using power law models and testing the model at high frequencies by conducting observations with the 100-meter Effelsberg Radio Telescope at 4-8 GHz in the predicted active windows. The observations led to the first high-frequency detection of bursts from this source. Detection of the bursts confirmed the chromaticity and the burst activity at higher frequencies.
The second work of this thesis involves tracking the RM variations of the bursts detected using upgraded Giant Metrewave Radio Telescope (uGMRT) in 550-750 MHz. First, a versatile polarization calibration pipeline was developed, that can work with different calibration sources. The pipeline was used to polarization calibration all the bursts. Thereafter, an RM measurement strategy was devised, which was used to make all the measurements. The RM measurements corroborated with measurements made using different instruments. Additionally, the sensitivity of uGMRT allowed for a thorough study of burst statistics against their fluences.
The third and final work of this thesis measures and interprets PAs of the bursts detected using uGMRT.
It begins with fitting one RM and one PA to the bursts of an observation and showing that PAs vary less than 7 degrees within four hours. In addition, it reports the PA variations to follow the periodicity of the source, suggesting that PA variations and periodicity have the same cause. It also tentatively reports PA to vary within an active window by few deg hr−1, and from one active window to another at the same phase by 0.1 deg day−1. Notwithstanding, the non-variability of PA is used to set constraints on the source models that explain the long-term periodicity.
If the frequency of light can be perceived as its color, polarization of light can be perceived as its shape.
Therefore, the title of the thesis reads Colors and shapes of light from the Fast Radio Burst 20180916B.
The Chapter 1 of this thesis shows how polarization of light traces an ellipse that has an orientation, an axial ratio, and a sense of rotation. Thereafter, it derives independent and additive parameterization of polarization, proposed by G. G. Stokes and named in his honor, the Stokes parameters. Lastly, the effect of Faraday rotation on the orientation of polarization of light is understood. The Chapter 2 of the thesis describes the phenomena of Fast Radio Bursts. It also describes the process of searching for a Fast Radio Burst, measuring different types of observables from the bursts, and the range of sciences that can be done with the measurements. The Chapter 3 of this thesis focuses solely on Fast Radio Burst 20180916B, which is regarded as the protagonist of this thesis. It contains all the known information about the source in one place. The Chapters 4, 5, and 6 are the science chapters of this thesis, which describe my contributions to the aforementioned three works of this thesis. Lastly, the final Chapter 7 concludes this thesis by describing my aspirations and motivations for my future.},
url = {https://hdl.handle.net/20.500.11811/14014}
}
Die folgenden Nutzungsbestimmungen sind mit dieser Ressource verbunden:
