Thomas Harrison » Research Staff

Thomas Harrison

Research Faculty, Observatory Research Specialist NMSUAstronomy
575.646.3628

Education
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Biographical Info

Research

Dr. Harrison’s main research interest is cataclysmic variables (CVs) and other interacting binaries observed across the electromagentic spectraum, concentrating on their fundamental properties: distances, component masses, luminosities, abundances, and emission processes. He has led or participated in several astrometric projects to measure the distances to cataclysmic variables and classical novae (and other astrophysically important stars, such as Cepheid and RR Lyr variables, very low metallicity stars, and planetary nebulae) using the Fine Guidance Sensors (FGS) on the Hubble Space Telescope.

Dr. Harrison specializes in infrared observations, and has obtained infrared spectra of cataclysmic variable stars and X-ray binaries using APO, the IRTF, the VLT, Keck, and Gemini. These data reveal that the secondary stars in these systems are peculiar with highly unusual abundance patterns. This suggests that their evolutionary history must be different from the currently accepted paradigm. Recently, graduate student Ryan Hamilton (now at SOFIA) modified MOOG to allow us to generate synthetic K-band spectra to determine absolute abundances. We have quantified the carbon abundance in several CVs and find it is dramatically subsolar (~20%). This is an ongoing, NSF-funded project that will eventually spread into the J and H-bands.

Another prominent research area is magnetic cataclysmic variables. We have used the Spitzer Observatory and data from the WISE mission to examine the mid-infrared spectra of Intermediate Polars (systems where B < 10 MG on the primary white dwarfs), and non-magnetic CVs finding that synchrotron emission is probably an important process in most CVs. We have also obtained X-ray observations of V1500 Cyg using XMM. These latter data show that the spin rate of the white dwarf is rapidly synchronizing with the orbital period (V1500 Cyg is a highly magnetic system that was knocked out of synchronous rotation by a classical nova eruption in 1975), much faster than had been predicted (200 years).

Recent graduates
  • Student name (link?), PhD, year. “Thesis title.”
  • Student name (link?), PhD, year. “Thesis title.”
Teaching

Dr. Harrison currently oversees the Astronomy 110 laboratories which includes the development of new labs, as well as maintenance of the campus observing facilities (two Meade 12″ telescopes). He has taught “Introduction to Astronomy” [ASTR-110], “Revolutionary Ideas in Science” [ASTR-301], and “Into the Final Frontier” [ASTR-308]. He also supervised the graduate seminar for Spring 2015 [ASTR-500].

 

Selected recent publications (student authors denoted by *):

Quantifying the Carbon Abundances in the Secondary Stars of SS Cygni, RU Pegasi, and GK Persei,, Harrison, T. E., & Hamilton, R. T. 2015, AJ, in press

The WISE Light Curves of Polars, Harrison, T. E., & Campbell, R. K., 2015, ApJSupp, 219, 32

The WISE Light Curves of Z Camelopardalis During Outburst: Evidence for Synchrotron Emission?, Harrison, T. E. 2014, ApJ, 791, L18

Herschel Observations of Circinus X-1 During Outburst and Quiescence, Harrison, T. E., et al. 2014, AJ, 148,1

Phase-Resolved Infrared Spectroscopy and Photometry of V1500 Cygni, and a Search for Similar Old Classical Novae, Harrison, T. E., et al. 2013, AJ, 146, 37

Hubble Space Telescope Fine Guidance Sensor Parallaxes for Four Classical Novae, Harrison, T. E., et al. 2013, ApJ, 767, 7

Herschel Observations of Cataclysmic Variables, Harrison, T. E., et al. 2013, AJ, 145, 19

 

All Publications

 

Updated 4 weeks ago.