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John P. Finley

Professor of Physics
Office: Physics 302
Telephone: (765) 494-5048
Fax: (765) 494-0706

B.S., Physics 1984 West Chester University
Ph.D., Physics 1990 University of Wisconsin-Madison

Research Interests

  • Optical, X-ray, and gamma ray studies of compact objects
  • The evolution of galactic supernova remnants and their impact on the interstellar medium
  • The origin of the soft X-ray background
  • The origin of the cosmic rays


Prof. Finley carries out a multi-wavelength research program in astrophysics with a primary emphasis on the physics of compact objects and their interstellar environs. The research program involves data acquired at optical wavelengths (energies ~ eV) through the very high energy gamma-ray (energies ~1012 eV). Compact objects are endpoints of stellar evolution and their extremes of density (p > pNuclear), magnetic field (B ~1012 Gauss), and temperature (TSurface > 106 K) present unique laboratories for the study of matter which can not be duplicated in a terrestrial setting. The physics and astronomy issues which are addressed in this research touch upon many fundamental physics issues: the equation of state of ultradense matter, the nature of matter in the presence of large magnetic fields, the coupling between the stellar matter and the dynamics of the stellar rotation, the electrodynamics of the magnetosphere and the origin of the cosmic rays, the origin of the "pulsar" mechanism, and the nature of the massive compact objects which lie at the heart of active galactic nuclei to name a few. Insight into these issues requires a comprehensive overview of the energetics in the optical, ultraviolet, X-ray, and gamma-ray energy bands of the electromagnetic spectrum. Prof. Finley participated in optical campaigns utilizing large telescopes of the National Optical Astronomy Observatory at both Kitt Peak in Arizona and Cerro Tololo in Chile, the National Observatory of Mexico(UNAM) in Baja California, Mexico and the European Southern Observatory (ESO) at Cerro La Silla in Chile. The ultraviolet, X-ray, and low energy gamma-ray studies have been carried out as a guest observer with several orbiting space based telescopes operated by NASA: the Extreme Ultraviolet Explorer (EUVE) in the UV domain; the Roentgen Satellite (ROSAT), the Advanced Satellite for Cosmology and Astrophysics (ASCA), and Chandra in the soft X-rays; the Rossi X-ray Timing Explorer (RXTE) and the Compton Gamma-Ray Observatory (CGRO) in the hard X-ray/gamma-ray region. At the highest accessible gamma-ray energies, as part of the VERITAS collaboration, Prof. Finley utilizes the 10m telescope at the Fred Lawrence Whipple Observatory on Mt. Hopkins in Southern Arizona.


Future research efforts involve the pursuit of the above outlined avenues of investigation utilizing the next generation of detectors in both the VHE gamma-ray domain and aboard X-ray/Gamma ray satellites. Prof. Finley is presently involved in the construction phase of a large project called VERITAS (the Very Energetic Radiation Imaging Telescope Array System), an array of 7 VHE gamma-ray telescopes which is the next step in ground based gamma-ray astronomy. The array, when complete, will push the sensitivity and energy threshold down by yet another order of magnitude and will overlap in bandpass with space based observatories for the first time. This proposal won an internal Smithsonian competition and construction began in fiscal year 2003 and will extend through fiscal year 2006. Funds in support of the Purdue effort originate with the Department of Energy. Prof. Finley plans to explore advanced detector designs utilizing recent technologies such as avalanche photodiodes (APDs) and hybrid photomultipliers for this effort. This project is expected to have duration well into the second decade of this millennium.

The research which Prof. Finley pursues in the X-ray domain will continue with advanced detectors which are soon to be placed in orbit by NASA. The large bandpass, imaging capabilities, and spectral resolution of CHANDRA will allow the programs which he has been carrying out to become more refined. The expected duration of the CHANDRA mission has a baseline of 10 years and will probably proceed beyond that time frame. The current suite of space based detectors which he has been utilizing as a guest observer will gradually be phased out over the first few years of the CHANDRA mission but will still be viable research tools in the interim.

Graduate Students Supervised

  • Sangwook Park, "The Large Scale Structure of the Soft X-ray Background Along the Galactic Plane" 1994-1997 currently on staff at the Goddard Space Flight Center.
  • Radhika Srinivasan, "High Energy Search for Pulsating Neutron Stars" 1995-1998 currently at the Indiana University School of Medicine, Department of Imaging Sciencenter.
  • Tony Hall, "X-ray Binary Systems" 1996-2000, currently a postdoctoral associate at Iowa State University.

Undergraduate Senior Theses Supervised

  • Andrew Becker, "Open Star Cluster Photometry" 1995.
  • Rollin Thomas, "The Enigmatic Clock in 2S 0114+65" 1996.
  • Jackie Jensen, "Multi-Wavelength Observations of Markarian 421" 1998.

Professional Experience

  • August, 2002-Present: Purdue University Department of Physics and Astronomy. Professor
  • August, 2002-August, 2006: Purdue University Department of Physics and Astronomy. Associate Dept. Head
  • August, 1999-July, 2000: F. L. Whipple Observatory, Harvard-Smithsonian Center for Astrophysics. Visiting Scientist
  • August, 1998-August, 2002: Purdue University Department of Physics and Astronomy. Associate Professor
  • August, 1993-August, 1998: Purdue University Department of Physics and Astronomy. Assistant Professor
  • March, 1991-August, 1993: University of Wisconsin{Madison Astrophysics Group. Assistant Scientist
  • September, 1990-March, 1991: University of Wisconsin{Madison High Energy Group. Research Associate
  • January 1984-June 1985: Argonne National Laboratory High Energy Physics Division. Research assistant under the direction of Dr. A. Barry Wicklund. ZGS E-441.

Selected Publications

  1. "TeV Gamma-Ray Observations of the Galactic Center" Kosack, K. et al., The Astrophysical Journal, 608:L97-L100, 2004 June 20.
  2. "X-Ray Spectral Variability of Extreme BL Lacertae Active Galactic Nucleus H1426+428" Falcone, A. D., Cui, W. K., & Finley, J. P., The Astrophysical Journal, 601:165-172, 2004 January 20.
  3. "Detection of TeV Gamma Rays from the BL Lacertae Object 1ES 1959+650 with the Whipple 10 Meter Telescope" Holder, J. et al., The Astrophysical Journal, 583:L9-L12, 2003 January 20.
  4. "VERITAS: the Very Energetic Radiation Imaging Telescope Array System" Weekes, T. C. et al., Astroparticle Physics, 17:221-243, 2002.
  5. "RXTE Observations of the X-Ray Binary 2S 0114+650" Hall, T. A., Finley, J. P., Corbet, R. H. D., & Thomas, R. C., The Astrophysical Journal , 536: 450-454, 2000 June 10.