X-ray Astronomy with CCDs: Calibration of the Advanced CCD Imaging Spectrometer and Observations of Rotation-powered Pulsars by Michael James Pivovaroff B.A. Physics, University of California, Berkeley (1993) Submitted to the Department of Physics in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY June 2000 c Massachusetts Institute of Technology 2000. All rights reserved.

Author...... Department of Physics May 2, 2000 Certifiedby...... George R. Ricker Senior Research Scientist Thesis Supervisor Certifiedby...... Victoria M. Kaspi Professor Thesis Supervisor Accepted by ...... Thomas J. Greytak Associate Department Head for Education

X-ray Astronomy with CCDs: Calibration of the Advanced CCD Imaging Spectrometer and Observations of Rotation-powered Pulsars

by Michael James Pivovaroff Submitted to the Department of Physics on May 2, 2000, in partial fulfillment of the requirements for the degree of Doctor of Philosophy

Abstract

This dissertation concerns the use of charge coupled devices (CCDs) for X-ray astron- omy. Part I of this thesis focuses on the calibration of the Advanced CCD Imaging Spectrometer (ACIS), one of the two primary focal plane instruments on the Chandra X-ray Observatory. I begin by presenting a series of measurements made using undis- persed synchrotron radiation. I analyzed the results of these experiments to extract parameters necessary to model the absolute detection efficiency of CCDs used as ref- erence standards for ACIS characterization. I also discuss a novel “mesh” technique I pioneered to non-destructively measure the sub-pixel structure of CCDs, including the channel stops and gates. This work also provided a valuable tool for understand- ing the way charge is collected inside certain regions of the ACIS detectors. Guided by the results of the mesh experiments, I performed additional measurements to con- strain recombination effects in the channel stops. Part II of this thesis concerns the X-ray properties of rotation-powered (radio) pulsars. High energy observations serve as a powerful diagnostic of the energetics and emission mechanisms of neutron stars. Associations between pulsars and the remnants of their supernovae provide independent measures of the distance and age of neutron stars, as well as constraints on their initial velocities, magnetic fields, and spin periods. I analyze ASCA and ROSAT observations of three young pulsars which are particularly well-suited for addressing these issues. I also present observations of the rotation-powered pulsar with the highest known magnetic field, and describe how the results relate to anomalous X-ray pulsars, another type of neutron star. Finally, IanalyzeChandra observations of the supernova remnant Cas A. These data fully demonstrate the capabilities of ACIS and reveal a previously unknown point source at the center of the remnant.

Thesis Supervisor: George Ricker Title: Senior Research Scientist

Thesis Supervisor: Victoria Kaspi Title: Professor Brat~ m Pivovarovym pos v waets to the Brothers Pivovaroff Acknowledgements

The last six years of my life have been dominated by the mostly enjoyable, always challenging, ommnipresence of MIT. I take this opportunity to thank all those indi- viduals who helped me not only with this thesis, but with all aspects of my graduate career and life outside of astrophysics. I am deeply indebted to my co-advisor George Ricker for taking a chance and giving me a home in the MIT CCD Laboratory. He has provided the freedom and support necessary to pursue my research interests and develop scientifically. I am equally appreciative of my other co-advisor, Vicky Kaspi. I have learned an incredible amount of astrophysics from her and have greatly benefited from her very attentive tutelage. I have truly enjoyed our interactions and am grateful for her willingness to always make time for me. In addition to George and Vicky, I wish to thank Saul Rappaport and Ray Ashoori, the other members of my thesis committee, for their valuable comments on my dissertation. I have also had the benefit of a collective guidance from five members of the CCD Lab. Together, they have taught me an incredible amount, and I am very happy and fortunate to have had such good teachers and friends. Steve Jones, renaissance scientist, gave me my first chance to take a lead role on a project and showed me how to simultaneously strive for excellence and happiness. Gregory Prigozhin, detector guru, has always been incredibly patient in explaining device physics, no matter how trivial the concept. I am grateful to him for always asking (and listening to) how I was doing. Roland Vanderspek, computer expert, always had time to help, from showing me the wonders of Apiezon to tricks in HTML. More importantly, he gave practical advice on how to maintain separation between my work and personal life. Steve Kissel, renaissance man, be it in tippling (local or abroad), literary discussion, or even the more prosaic experimental work, was always a willing and instructive guide and collaborator. Mark Bautz, dean of the lab, who more than any other person, shaped me as a scientist. Additionally, he provided significant insight and perspective at crucial points during my graduate career. I am also grateful for the friendships developed with Tye Brady, Dave Breslau, Bryan Gaensler, Fred Baganoff, Keith Gendreau, Bev LaMarr, Mike Malm, and Glen Monnelly. Keith showed me the ropes when I first got to the Institute, taught me the joys of home brew, and made me feel like I was part of the team. Mike and Glen de- served special attention for having endured my idiosyncrasies and musical despotism while sharing an office with me the last three years. I also wish to thank Fred Miller, Rosemary Hanlon, Kelley Fischer, and Jean Farewell for all their assistance and help, and more generally, making the Lab run smoothly. The process of general exams was a particularly grueling experience for me. Two people deserve special thanks. Al Levine was the one person I could consistently count on for help, both in solving the more abusive exam problems and in explaining the underlying concepts. Katy Hope provided an unlimited amount of moral support and had confidence in my eventual success. My fellow graduate students in the astrophysics division proved to be not only generous and helpful, but amazing friends. Derek Fox, Patrick Wojdowski, Jeff Kom- mers, Froney Crawford, and Pete Csatorday answered innumerable question and gave me many tips on astrophysical data analysis. Pete, Froney and I started at the same time. We took classes together, struggled through various ordeals, and spent count- less hours in the Hong Kong, Muddy Charles, and Miracle of Science putting it all in perspective. In addition to those already mentioned, I had the pleasure to work with additional astronomers both at and away from MIT. I thank Eric Gotthelf, Fernando Camilo, and Deepto Chakrabarty for all their input and help with our collaborations. I also wish to thank Martin Weisskopf and Steve Murray for sending me figures of Chandra’s other science instruments, and Ken Ebisawa for invaluable assistance with analysis of ASCA GIS data. Throughout grad school, I have counted on a number of different artists and their work for spiritual re-charging. In no particular order, I credit Merle Haggard, Richard Diebenkorn, Professor Beam of Central Kentucky, Miles Davis, Charles Bukowski, Liz Phair, Wayne Shorter, Radiohead, Robinson Jeffers, Willie Nelson, Mark Rothko, Portishead, David Mamet, Professor Aberlour of Speyside, and the American Analog Set. A smaller group of people outside of physics deserve an equal amount of recogni- tion. Jay Yap, Craig Colby, Stacey Balius, Clint Harder, and Matt Boone helped me maintain sanity. I depended on them to keep me connected with reality and to remind me of a world away from the Institute. I single out three friends for playing particu- larly influential roles and always watching my back. Sam Smith has continually given sagely advice and recommended the choicest of tunes. I have always admired your integrity and will continue to appreciate your friendship. Paul Ellickson endured me as a house-mate for three years and burned the better part of a decade doing a whole lot of nothing with me. I hope you enjoyed and valued this time as much as I did. Finally, I thank Sarah Elmes for her understanding and trust. You reminded me to relax, filled me with happiness, and helped me finish this long journey. I close by acknowledging the unwavering support and love of my parents, Jo Anne and Daniel, and my sister, Jamie. My mother taught me the joys of reading and encouraged my curiosity and inquisitiveness, even in the face of destroyed household appliances. My father instilled in me the virtue of taking pride in my work and always emphasized the importance of putting all my energy and ability into whatever projects I’ve undertaken. My sister blazed a trail for me to follow through both college and grad school. I constantly relied upon your endless supply of faith and excitement for my efforts.