Using a ground-based photometric telescope for observing global modes of solar oscillation

Persistent Link:
http://hdl.handle.net/10150/284258
Title:
Using a ground-based photometric telescope for observing global modes of solar oscillation
Author:
Shah, Nitesh Navin
Issue Date:
2000
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
A new technique for ground based photometric helioseismology has been implemented. The technique is able to detect low amplitude oscillations in the solar irradiance by making simultaneous measurements at continuum wavelengths of 0.507 μm, 0.747 μm, and 1.600 μm. Data is collected from a rectangular region covering approximately 57% of the solar disk, extending ±0.30 R(⊙) about the solar rotational axis, and ±0.38 R(⊙) about the solar equator, using square pixels varying in linear size from 0.032 R(⊙) to 0.053 R(⊙). A differential spatial filter is applied, taking advantage of cancellations of undesired variations and forming a signal which is sensitive to most modes with spherical harmonic index l ≤ 7. Linear combinations are made of the three solar signals and the telescope internal Temperature signal, mitigating the deleterious effects of the terrestrial atmosphere and of local temperature variations. Frequencies of local maxima in the Power Spectrum of the residual signal, in the 400 μHz to 850 μHz range, are found to be consistent with those determined by solar limb profile measurements made in 1979. The measured coincidence levels indicate that the probability that the 1979 and 1999 data sets are random with respect to one another is approximately 5 x 10⁻⁹. Frequency shifts between the 1979 data and the 1999 data, possibly related to the solar activity cycle, are found: δν(n=1;l=4,...,7) = -0.16 ± 0.01 μHz, δν(n=2;l=3,...,7) = -0.04 ± 0.01 μHz, and δν(n=3;l=2,...,4) = -0.11 ± 0.01 μHz.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Physics, Astronomy and Astrophysics.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Physics
Degree Grantor:
University of Arizona
Advisor:
Hill, Henry A.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleUsing a ground-based photometric telescope for observing global modes of solar oscillationen_US
dc.creatorShah, Nitesh Navinen_US
dc.contributor.authorShah, Nitesh Navinen_US
dc.date.issued2000en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractA new technique for ground based photometric helioseismology has been implemented. The technique is able to detect low amplitude oscillations in the solar irradiance by making simultaneous measurements at continuum wavelengths of 0.507 μm, 0.747 μm, and 1.600 μm. Data is collected from a rectangular region covering approximately 57% of the solar disk, extending ±0.30 R(⊙) about the solar rotational axis, and ±0.38 R(⊙) about the solar equator, using square pixels varying in linear size from 0.032 R(⊙) to 0.053 R(⊙). A differential spatial filter is applied, taking advantage of cancellations of undesired variations and forming a signal which is sensitive to most modes with spherical harmonic index l ≤ 7. Linear combinations are made of the three solar signals and the telescope internal Temperature signal, mitigating the deleterious effects of the terrestrial atmosphere and of local temperature variations. Frequencies of local maxima in the Power Spectrum of the residual signal, in the 400 μHz to 850 μHz range, are found to be consistent with those determined by solar limb profile measurements made in 1979. The measured coincidence levels indicate that the probability that the 1979 and 1999 data sets are random with respect to one another is approximately 5 x 10⁻⁹. Frequency shifts between the 1979 data and the 1999 data, possibly related to the solar activity cycle, are found: δν(n=1;l=4,...,7) = -0.16 ± 0.01 μHz, δν(n=2;l=3,...,7) = -0.04 ± 0.01 μHz, and δν(n=3;l=2,...,4) = -0.11 ± 0.01 μHz.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectPhysics, Astronomy and Astrophysics.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplinePhysicsen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorHill, Henry A.en_US
dc.identifier.proquest9992072en_US
dc.identifier.bibrecord.b41166796en_US
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