Although I have been trained as a research astronomer, my interests are quite multi-discipline and span many of the physical sciences; indeed, I am most drawn to areas of research which demand knowledge and skills in multiple fields. Although I had limited access to research opportunities as an undergraduate, I took advantage of as many summer internship programs as possible, and pursued whatever opportunities arouse at my home universities.
Since arriving at UC Santa Cruz, I have been fortunate enough to work for the Laboratory for Adaptive Optics, the research wing of the Center for Adaptive Optics, under the direction of Don Gavel and Claire Max. This has been a perfect opportunity, as it allows me to learn and use elements of many different disciplines, including Astronomy (a clear and fundamental knowledge and understanding of the needs and requirements of the Astronomy Community), Theoretical Optical Physics, Laboratory Optics, and Adaptive Optics.
The Laboratory for Adaptive Optics :
The Pyramid Pyramid Project
Dr. Donald
Gavel, Dr. Claire Max, UC Santa Cruz, Advisors
I am the Lead Graduate Researcher on the LAO's Lenslet-based Pyramid Project.
This page is being updated...
Next Generation Wavefront Sensors:
Lenslet Based Pyramid Wavefront Sensing (PWFS)
Dr. Donald
Gavel, Dr. Claire Max, UC Santa Cruz, Advisors
Since arriving at UCSC as a graduate student, I have felt priviledged (and quite humbled) by the opportunity to work in one of the world's foremost optical laboratories for the study and implementation of cutting edge Adaptive Optics technology. My major area of research for LAO has been the characterization and bench testing of a novel implementation of Roberto Ragazzoni's Pyramid Wavefront Sensor: Lenslet-based PWFS.
Although PWFS systems offer performance and sensitivity gains over traditional Shack-Hartman sensors (as well as a number of other reasons to prefer them as the wavefront sensor of choice for large telescopes), the original formulation is hampered by the nature of its architecture. Brian Bauman, an optical engineer at LAO, conceived of a clever way to simplify the design using ubiquitous lenslet-array technology.
The first results from testing this new implementation have now been published; the paper can be found here, and several posters can be found in publications. More results will be coming soon; keep an eye on the publications page.
Ultraviolet
Spectroscopic Analysis of Mass Flow
in the Interacting Binary U Cephei
Dr.
George McCluskey, Dr. Gary DeLeo, Lehigh University, REU Advisors
U Cephei is a quiescent, interacting, Algol-type binary (B7 V+ G8 III-IV) that ranges in magnitude from 6.8 to 9.2, with an orbital period of approximately 2.5 days. The International Ultraviolet Explorer satellite, on which Dr. McCluskey was a frequent guest investigator, provided adequate phase coverage spectra across 1.2 orbits in 1989, in both the near and far UV. We consructed light curves at several different UV wavelengths from this data in an attempt to understand the variable mass flow phenomena known to occur in this system.
The light curves indicated significant departures from those expected from quiescent eclipsing systems. It is known that U Cephei exhibited a major mass-flow outburst in 1986, and it appears that a weaker outburst may be visible in the spectra that we analyzed. It may be concluded that U Cephei, and a number of other Algol-type binaries studied elsewhere, show pseudophotospheric accretion phenomena, mass exchange and systemic mass loss with occasional, variable, short-term increases in activity.
The abstract can be found here.
Also, Dr. McCluskey is one of the editors of an excellent text on Interacting Binaries, The Realm of Interacting Binary Stars. The text can be purchased here.
Impact Ejection Panspermia
Dr.
Greg Laughlin, UC Santa Cruz, Advisor
The word 'Panspermia' is from the Greek, and literally means ‘seeds everywhere.’ In its modern usage, it refers to the concept that life exists and is distributed throughout space in the form of microbes or spores, which pass from world to world and spark the growth of life. Panspermia as a valid scientific hypothesis has a long and pedigreed history, originating with the Greeks and passing through many modern theoretical incarnations.
Our research specifically focused on examining the transport of microbial life on rock ejected from earth. We wanted to answer the following question: What is the probability that life has been ejected from our planet over the course of our history, and has then impacted another world in our galaxy? The answer to ths question has profound ramifications: not only those concerning the possibility of passing earth life to other worlds, but those concerning the origination of life on earth itself.
The results of our work found that, although there are microrganisms that are easily capable of surviving all of the challenges of interstellar travel, the probability of capture by another planetary system is vanishingly small. It should be noted that this in no way negates the possibilty of transport between worlds in our own system, a situation that seems quite possible.
A link to the poster of our work can be found here.
Discerning
the Surface Figures of the Keck Mirror Segmants
via Shack-Hartmann
Wavefront Sensing
Dr.
Gary Chanan, UC Irvine Wavefront Sensing Group, REU Advisor
The difficulty in assuring high quality images from multi-segmented telescopes, such as the Keck and most proposed future large telescopes, arises from two different considerations: the correct positioning of the segments with respect to each other, a process known as phasing, and errors inherent in the individual segments themselves. These errors in segment surface figures result from gravitational and structural stress, and introduce incoherence in addition to that caused by segment phasing error.
The desired error in the surface figure of a Keck segment relative to its design specification is 40nm, and the determination of the actual error is made using the Phasing Camera System, which is an implementation of Shack-Hartman wavefront sensing. At the time I started my research, the computational algorithm in use was built on a modal approach, ie., an assumption that the wavefront aberrations resulting from segment distortions could be described in terms of combinations of Zernike Polynomials. This approach simplified the requisite calculations, but was known to lead to inaccuracies in surface characterization. My project was to implement a zonal algorithm, which completely solves for the surface figure without the assumption of a zernike polynomial combination.
The paper that resulted from this project, Zonal-Trigonal Implementation of Shack-Hartman Wavefront Sensing: Application to the Surface Figures of the Keck Telescope, can be found here.
Scientific Creativity Through Digital Media
Dr.
Hideo Mabuchi, CalTech, SURF Advisor
Although not hard science, this project went towards the development of another of my great loves: the presentation of difficult science to those without a science background. The purpose of the project was to explore methods of utilizing digital multimedia to present inherently difficult concepts in quantum mechanics to an educated lay audience. Although our design group was specifically focused on the topics of Bell inequalities and quantum entanglement, our desire was to create a presentation format that would lend itself generically to the instruction of most difficult science concepts. Even given the fact that we had an extremely short development period (< 10 weeks), we were able to show proof of concept and garnered interest from many media organizations, including the Annenberg foundation.
Some of my writings and reports on the project can be found here (coming soon).
Scientific Illustration
Dr. Alfred
A. Actor, Pennsylvania State University, Advisor
In many ways, I owe a great deal of both my love of physics and the development of my career path to this brilliant and dedicated educator and quantum field theorist. When I returned to university after 15 years of absence, Dr. Actor acted as both my mentor and my friend, spending countless hours in free-form discussion about the nature of the physical world, the beauty of mathematics, and the quest for understanding. Indeed, if it were not for his infectious love of science, I would more then likely not be pursuing my current path.
That being said, he also provided me with many excellent opportunities, one of which was the development of my skills as a science illustrator. An example of my work can be found in his paper Point and Line Boundaries in Scalar Casimir Theory, found here.