Dissertation/Thesis Abstract

Tidally triggered star formation in gravitationally interacting galaxies and selected work in optical instrumentation
by Woods, Deborah Freedman, Ph.D., Harvard University, 2009, 299; 3385558
Abstract (Summary)

In the first part of this thesis I present studies of tidally triggered star formation in pairs of gravitationally interacting galaxies. I use spectroscopic and photometric observations of local systems to demonstrate that triggered star formation depends both on intrinsic galaxy properties and on relative properties of the system. Minor galaxy interactions, where the luminosity ratio of the galaxies exceeds about six, produce triggered star formation only in the lower luminosity companion. In interactions between galaxies of similar luminosity, the blue galaxies exhibit tidally triggered star formation, but the red galaxies do not.

I measure the strength, frequency, and timescale of gravitational tidal interactions between galaxy pairs in a complete spectroscopic survey at redshifts 0.08 to 0.38. A third of the galaxies with young stellar populations interacting with a companion of similar luminosity experience enhanced star formation activity. However, the most extreme bursts of triggered star formation are rare and short lived. The typical duration for enhanced star formation in interacting galaxies is of order 300 Myr.

In the second part of this thesis I describe the development of optical instrumentation in support of large spectroscopic surveys. I analyze the effects of flexure in the Binospec spectrograph, a multi-object spectrograph for the 6.5-meter MMT telescope at Mt. Hopkins, AZ. I design the active flexure control system and the calibration system, two physically distinct systems that together will enable accurate and stable spectro-photometric calibration.

Improvements to telescope collimation and mirror support provide additional benefit to spectroscopic surveys through superior image quality and spectrograph efficiency. I design and build a Shack-Hartmann wavefront sensor for the 1.5-meter Tillinghast telescope at Mount Hopkins, AZ. The wavefront sensor and accompanying software serve as valuable tools for measuring and correcting for optical aberrations.

Indexing (document details)
Advisor: Fabricant, Daniel G., Geller, Margaret J.
Commitee:
School: Harvard University
School Location: United States -- Massachusetts
Source: DAI-B 70/11, Dissertation Abstracts International
Source Type: DISSERTATION
Subjects: Astronomy
Keywords: Flexure, Galaxy pairs, Star formation, Tidally triggered, Wavefront sensor
Publication Number: 3385558
ISBN: 9781109494709
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