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Bill Wheaton
William A Wheaton is a retired astrophysicist (PhD UCSD 1976) living (1979-2010 ff) in Pasadena CA. At the age of 77, I must acknowledge that in the last 5 or 10 years I am rapidly losing my memory, to the point that I can barely do even simple calculations I used to breeze through in my head. It is embarassing to admit of course, but silly to deny. So I will likely be a somewhat different, and diminished person (though hopefully not "a grave man if you look for me tomorrow").
I am also disabled since birth, due to a cartilage defect (diastrophic displasia, affecting almost all my joints to some extent) that has left me with artifical hips, knees, and a partially replaced shoulder. Too bad, but I can only be grateful for the advances in orthopedic surgery, year after year, that have staved off total disability, along with the outstanding doctors (Drs. MacBride and Shorb, Oklahoma City, before 1950; Dr. Boast, Shriners Hosp, San Francisco CA, 1953 - 1956; Dr Amstutz, 1982-2000), and many other medical people whose combined efforts have saved me.
Unfortunately there are a number of holes in my professional career, probably partially due to my disability. In particular my thesis, while apprently considered good, was never published due to the stresses of post-doctoral work with Walter Lewin's wonderful group at MIT (mostly on SAS 3 and HEAO-1, 1976-1979).
The greatest blessings, however, have been my wife, Georgia Hale, son David Wheaton, and two spectacular granddaughters, Aurora and Myrina Wheaton. I am enormously grateful to them for the happiest periods in my life. I am also greatly indebted to many wonderful friends who have inspired and supported me, year after year.
My graduate school work was mostly in X-Ray astronomy, my thesis on hard X-ray (7 to 500 kev; significant detections of diffuse emission out to about 50 keV) mapping of the Milky Way, using the UCSD Cosmic X-Ray Telescope on OSO-7, Principle Investigator Larry S Peterson. My most significant publication was observation of a cosmic gamma-ray burst, with position localization to a few degrees (Wheaton et al, ApJ Letters, 1973).
After 1979 I went to the Caltech/JPL Jet Propulsion Laboratory, working with data from Allan S Jacobson's high resolution Ge spectrometer on NASA's Third High Energy Astronomy Observatory, HEAO 3. My most significant contribution to this work was a refomulation of the analysis to make better use of data dominated by very low count rate Poisson distributed observations. This methodology made possible the paper of Mahoney et al. ApJ 1986, reporting the observation of the 26Al 1.8 MeV emission of the Milky Way. Because the decay lifetime of 26Al is only on the order of 1 million years, Mahoney et al concluded that radioactive 26Al is constantly being renewed in the Milky Way on that time scale of 1 million years or less, with roughly 3 Solar Masses of Al26 being currently present in the Galaxy, and thus that the creation of new elemental matter is constanly ongoing from recent supernovi.
It had often been claimed (P. R. Bevinton, "Data Reduction and Error Analysis for the Physcal Sciences", Magraw-Hill, 1969) that accurate count rate data could only be made with observed event counts of over ~30 or so per data bin. In particular, estimates of the uncertainty in each observation, as derived from the square root of the OBSERVED counts in a bin, are typically seriously biased. Details were presented later in a 1990 ApJ paper by Wheaton et al. that shows how unbiased estimates of photon fluxes, based on abitrarily low expected counts, can be obtained by taking care that the weighting of each data bin is strictly independent of the observed photon counts in that bin. The HEAO 3 spectrometer often returned count rates at high energies of less than one count per day, with only ~20 sec or so of observing time per bin, as dictated by the observatory spin rate and the ~30 deg FOV of the instrument. The reformulation of the 0.511 MeV positron annihilation emission of the Galactic Center, as first reported (Riegler et al, 1980), which had appeared to be variable on time scales of less than a year, was consequently shown to be consistent with a constant over the HEAO 3 observations. On the other hand, in the 1980s, Jim Ling and I were able to show that there was strong and variable 0.511 MeV emission from the black hole candidate Cygnus X-1.
I am also disabled since birth, due to a cartilage defect (diastrophic displasia, affecting almost all my joints to some extent) that has left me with artifical hips, knees, and a partially replaced shoulder. Too bad, but I can only be grateful for the advances in orthopedic surgery, year after year, that have staved off total disability, along with the outstanding doctors (Drs. MacBride and Shorb, Oklahoma City, before 1950; Dr. Boast, Shriners Hosp, San Francisco CA, 1953 - 1956; Dr Amstutz, 1982-2000), and many other medical people whose combined efforts have saved me.
Unfortunately there are a number of holes in my professional career, probably partially due to my disability. In particular my thesis, while apprently considered good, was never published due to the stresses of post-doctoral work with Walter Lewin's wonderful group at MIT (mostly on SAS 3 and HEAO-1, 1976-1979).
The greatest blessings, however, have been my wife, Georgia Hale, son David Wheaton, and two spectacular granddaughters, Aurora and Myrina Wheaton. I am enormously grateful to them for the happiest periods in my life. I am also greatly indebted to many wonderful friends who have inspired and supported me, year after year.
My graduate school work was mostly in X-Ray astronomy, my thesis on hard X-ray (7 to 500 kev; significant detections of diffuse emission out to about 50 keV) mapping of the Milky Way, using the UCSD Cosmic X-Ray Telescope on OSO-7, Principle Investigator Larry S Peterson. My most significant publication was observation of a cosmic gamma-ray burst, with position localization to a few degrees (Wheaton et al, ApJ Letters, 1973).
After 1979 I went to the Caltech/JPL Jet Propulsion Laboratory, working with data from Allan S Jacobson's high resolution Ge spectrometer on NASA's Third High Energy Astronomy Observatory, HEAO 3. My most significant contribution to this work was a refomulation of the analysis to make better use of data dominated by very low count rate Poisson distributed observations. This methodology made possible the paper of Mahoney et al. ApJ 1986, reporting the observation of the 26Al 1.8 MeV emission of the Milky Way. Because the decay lifetime of 26Al is only on the order of 1 million years, Mahoney et al concluded that radioactive 26Al is constantly being renewed in the Milky Way on that time scale of 1 million years or less, with roughly 3 Solar Masses of Al26 being currently present in the Galaxy, and thus that the creation of new elemental matter is constanly ongoing from recent supernovi.
It had often been claimed (P. R. Bevinton, "Data Reduction and Error Analysis for the Physcal Sciences", Magraw-Hill, 1969) that accurate count rate data could only be made with observed event counts of over ~30 or so per data bin. In particular, estimates of the uncertainty in each observation, as derived from the square root of the OBSERVED counts in a bin, are typically seriously biased. Details were presented later in a 1990 ApJ paper by Wheaton et al. that shows how unbiased estimates of photon fluxes, based on abitrarily low expected counts, can be obtained by taking care that the weighting of each data bin is strictly independent of the observed photon counts in that bin. The HEAO 3 spectrometer often returned count rates at high energies of less than one count per day, with only ~20 sec or so of observing time per bin, as dictated by the observatory spin rate and the ~30 deg FOV of the instrument. The reformulation of the 0.511 MeV positron annihilation emission of the Galactic Center, as first reported (Riegler et al, 1980), which had appeared to be variable on time scales of less than a year, was consequently shown to be consistent with a constant over the HEAO 3 observations. On the other hand, in the 1980s, Jim Ling and I were able to show that there was strong and variable 0.511 MeV emission from the black hole candidate Cygnus X-1.
