Calvin College Physics and Astronomy Department

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Deborah B. Haarsma: Research

A possible gravitational lens? In my research, I pursue questions about galaxies and the universe as a whole, and what can be learned about them by observing at radio wavelengths. Most of my work has been in the area of gravitational lensing, a phenomenon of general relativity in which light is bent by gravitational fields, distorting and multiplying the images of distant galaxies. I am currently working on a search for new gravitational lenses (see picture at left). Gravitational lenses can be used to determine the mass and dark matter content of galaxies by measuring their effect on more distant radio sources. Gravitational lenses can also be used to determine the expansion rate of the universe, its mass density, and the cosmological constant, which in turn determine the age, curvature, and future of the universe. I have also studied the changes in the properties of galaxies over the history of the universe, using the faint radio emission of distant young galaxies.

My work is supported by a Cottrell College Science Award from Research Corporation entitled ``Cosmological Parameters Through Gravitational Lens Time Delays''.

Research links
Journal articles

Links for my summer research students:

o Careers in Astronomy
o 2002 NRAO Synthesis Imaging Summer School (powerpoint presentations)
o List of unix basic unix commands | Another list of basic commands | Emacs commands
o Basics of radio astronomy from NRAO | from the Jet Propulsion Lab
o Interferometry simulation | Fourier transform examples
o The VLA for Astronomers, especially the | Overview | Image Gallery | VLA status summary
VLA Archive Search | JObserve | VLA Calibrator Manual
o Gravitational lens introduction and simulation from Pete Newbury | Lens an astrophysicist | SimpLens javascript
o Review article on gravitational lenses
o CASTLeS Lens Data Base | Keeton's modeling software | DS9 imaging manual
o NASA ADS Abstract Service | LANL astro-ph preprint server
o FIRST survey | SDSS survey | NED
o Travel Expense forms: pdf | Excel

Journal Articles:

You can browse a complete list of my refereed publications and conference proceedings as listed in the NASA Astrophysics Data System Abstract Service.

``Toward a Resolution of the Discrepancy Between Different Estimators of Star Formation Rate.''
Hopkins, A. M., Connolly, A. J., Haarsma, D. B., and Cram, L. E. 2001
Astronomical Journal, 122, 288.

``Further investigation of the time delay, magnification ratios, and variability in the gravitational lens 0218+357.''
Cohen, A. S., Hewitt, J. N., Moore, C. B., Haarsma, D. B. 2000
Astrophysical Journal, 545, 578.

``Faint Radio Sources and Star Formation History.''
Haarsma, D. B., Partridge, R. B., Windhorst, R. A., and Richards, E. A. 2000.
Astrophysical Journal, 544, 651

``The Radio Wavelength Time Delay of Gravitational Lens 0957+561.''
Haarsma, D. B., Hewitt, J. N., Lehar, J., Burke, B. F. 1999.
Astrophysical Journal, 510, 64.

``Radio Wavelength Constraints on the Sources of the Far Infrared Background.''
Haarsma, D. B., Partridge, R. B. 1998.
Astrophysical Journal, 503, L5.

``Low Surface Brightness Radio Structure in the Field of Gravitational Lens 0957+561,''
Avruch, I. M., Cohen, A. S., Lehar, J., Conner, S. R., Haarsma, D. B., Burke, B. F. 1997.
Astrophysical Journal, 488, L121.

``The 6 cm Light Curves of B0957+561, 1979-1994: New Features and Implications for the Time Delay,''
Haarsma, D. B., Hewitt, J. N., Lehar, J., Burke, B. F. 1997.
Astrophysical Journal, 479, 102.

Content updated August 2004


				Deborah Haarsma