I work in the rich field of pulsars. My work focuses on how pulsars can be used to detect and study gravitational waves from exotic astrophysical objects like supermassive binary black holes or cosmic strings. By pushing precision pulsar timing to its limits with world-class radio telescopes and instrumentation and continually improving data analysis techniques, the pulsar community is poised to detect extremely low-frequency gravitational waves within five to ten years and begin a new era in the study of black holes, gravity, and currently unknown astrophysical phenomena.
Work in this vein has steered my interests in many varied directions. Study of extraordinary systems like J0737-3039 (the double pulsar) or J1614-2230 (a two-solar-mass neutron star) allow us to test theories of gravity with unprecedented precision and learn things about nuclear physics that cannot be learned in any other way. How many comparably special systems there are in the galaxy is not known, but ongoing and near-future surveys from radio to gamma ray wavelengths stand to unveil much about the galactic pulsar population. Optimizing the efficacy of these surveys is an interesting problem. Dynamics of the ionized interstellar medium and phenomena intrinsic to pulsars like pulse jitter and micro glitches are obstacles to extremely high-precision timing, but in their own right, are fantastically interesting. Careful study of them can aid precision timing efforts and yield exciting stand-alone science.
Here's a little bit about my background. I'm from Ceres, California. I don't know exactly when I developed an affinity for astronomy, but I was very young. I graduated from Ceres High School in 2003 before attending The University of California, Berkeley (Go Bears!). I double-majored in physics and math at Berkeley and received my B.A. in 2007. While at Berkeley, I had the opportunity to work with members of the CARMA observatory, my first experience with radio astronomy. I began my doctoral study at Cornell University in 2008. In my first several years at Cornell I seized opportunities to teach undergraduate courses in the Department of Physics, something I greatly enjoyed and found very rewarding. I pursued research opportunities within Cornell's Department of Astronomy, and found my niche working with Professor Jim Cordes and other members of Cornell's pulsar group.
6. D. R. Madison, J. M. Cordes, & S. Chatterjee, “Assessing Pulsar Timing Array Sensitivity to Gravitational Wave Bursts with Memory”, ApJ 788, 141 (2014)
5. D. R. Madison, S. Chatterjee, & J. M. Cordes, “The Benefits of VLBI Astrometry to Pulsar Timing Array Searches for Gravitational Radiation”, ApJ 777, 104 (2013)
4. Z. Arzoumanian, A. Brazier, S. Burke-Spolaor, S. Chamberlin, S. Chatterjee, J. M. Cordes, P. B. Demorest, X. Deng, T. Dolch, J. A. Ellis, R. D. Ferdman, N. Garver-Daniels, F. Jenet, G. Jones, V. M. Kaspi, M. Koop, M. Lam, T. J. W. Lazio, A. N. Lommen, D. R. Lorimer, J. Luo, R. S. Lynch, D. R. Madison, M. McLaughlin, S. T. McWilliams, D. J. Nice, N. Palliyaguru, T. T. Pennucci, S. M. Ransom, A. Sesana, X. Siemens, I. H. Stairs, D. R. Stinebring, K. Stovall, J. Swiggum, M. Vallisneri, R. van Haasteren, Y. Wang, & W. W. Zhu, “NANOGrav Limits on Gravitational Waves from Individual Supermassive Black Hole Binaries in Circular Orbits”, ApJ (2014)
3. J. B. Wang, G. Hobbs, W. Coles, R. M. Shannon, X. -J. Zhu, D. R. Madison, M. Kerr, V. Ravi, M. J. Keith, R. N. Manchester, Y. Levin, M. Bailes, N. D. R. Bhat, S. Burke-Spolaor, S. Dai, S. Oslowski, W. van Straten, L. Toomey, N. Wang, & L. Wen, “Searching for Gravitational Wave Memory Bursts with the Parkes Pulsar Timing Array”, MNRAS (~2014)
2. X.-J. Zhu, G. Hobbs, L. Wen, W. A. Coles, J.-B. Wang, R. M. Shannon, R. N. Manchester, M. Bailes, N. D. R. Bhat, S. Burke-Spolaor, S. Dai, M. J. Keith, M. Kerr, Y. Levin, D. R. Madison, S. Oslowski, V. Ravi, L. Toomey, & W. van Straten, “All-sky Search for Continuous Gravitational Waves in the PPTA DR1 Data”, MNRAS (2014)
1. T. Dolch, M. T. Lam, J. Cordes, S. Chatterjee, C. Bassa, B. Bhattacharyya, D. J. Champion, I. Cognard, K. Crowter, P. B. Demorest, J. W. T. Hessels, G. Janssen, F. A. Jenet, G. Jones, C. Jordan, R. Karuppusamy, V. Kondratiev, M. Keith, M. Kramer, P. Lazarus, T. J. W. Lazio, K. J. Lee, M. A. McLaughlin, J. Roy, R. M . Shannon, I. Stairs, K. Stovall, J. P. W. Verbiest, D. R. Madison, N. Palliyaguru, D. Perrodin, S. Ransom, B. Stappers, W. W. Zhu, S. Dai, G. Desvignes, L. Guillemot, K. Liu, A. Lyne, B. B. P. Perera, E. Petroff, J. M. Rankin, & R. Smits, “A 24-Hour Global Campaign to Assess Precision Timing of the Millisecond Pulsar J1713+0747”, ApJ (2014)