Dan Homan
One of the things that excites me most about Physics is our continuing struggle to develop a better understanding of how the world works at a fundamental level. We Physicists also work to apply that understanding to complex, real world problems. For me, one of the great pleasures of Physics is finding creative ways to address these challenges. I enjoy teaching Physics and Astronomy at all levels in our curriculum.
Learning & Teaching
- ASTR 100 Current Topics in Astronomy
- ASTR 125 Quarks to the Cosmos
- ASTR 300 Astrophysics
- ASTR 311 Observational Astronomy
- PHYS 122 General Physics II
- PHYS 125 Principles of Physics I
- PHYS 126 Principles of Physics II
- PHYS 127 Principles of Physics III
- PHYS 305 Classical Mechanics
- PHYS 306 Electricity & Magnetism
- PHYS 320 Thermodynamics
- PHYS 400 Physics Seminar
- Professor, Denison University: 2015—Present
- Associate Professor, Denison University: 2009—2015
- Assistant Professor, Denison University: 2003—2009
- Jansky Fellow, National Radio Astronomy Observatory: 2001—2003
Research
Black Holes and Cosmic Jets
I study distant active galaxies. Active galaxies are extremely energetic galaxies, giving off so much energy that they can be viewed from billions of light years away. All of the unusual, energetic behavior in an active galaxy can ultimately be traced to its galactic center or nucleus, a region only a few light years across. These objects are therefore often called "Active Galactic Nuclei" or "AGN" for short. It is now believed that all AGN have, at their center, a super-massive black hole that is millions or even billions of times the mass of our Sun. Matter falling inward toward the black hole dramatically releases energy to generate the phenomena we observe.
There is a sub-class of AGN that have strong jets of plasma which stream outward from the galactic nucleus and are visible at radio wavelengths. These radio jets come in a number of morphologies with the most spectacular maintaining collimated flows for tens or even hundreds of thousands of light-years before terminating at hotspots in large, inflated radio lobes. I study these jets to understand their physical properties and how they are created by the super-massive black hole and accretion disk of in-falling matter at the center of the galaxy.
Works
Selected Recent Publications:
- “Residual Entropy as a Diagnostic and Stopping Metric for CLEAN” by Homan, D. C., Roth, J. S., Pushkarev, A. B. (2024). The Astronomical Journal, Volume 167, Issue 1, id.11, 8 pp.
- “MOJAVE XIX: Brightness Temperatures and Intrinsic Properties of Blazar Jets” by Homan, D. C., Cohen, M. H., Hovatta, T., Kellermann, K. I., Kovalev, Y. Y., Lister, M. L., Popkov, A. V., Pushkarev, A. B., Ros, E., Savolainen, T. (2021). The Astrophysical Journal, Volume 923, Issue 1, id.67, 23 pp.
- “MOJAVE: XVIII. Kinematics and Inner Jet Evolution of Bright Radio-Loud Active Galaxies by M. L. Lister, D. C. Homan, K. I. Kellermann, Y. Y. Kovalev, A. B. Pushkarev, E. Ros, T. Savolainen. (2021) The Astrophysical Journal, Volume 923, Issue 1, id.30, 19 pp.
- “TXS 0128+554: A Young Gamma-Ray-emitting Active Galactic Nucleus with Episodic Jet Activity” by M. L. Lister, D. C. Homan, Kovalev, Y. Y., Mandal, S., Pushkarev, A. B., Siemiginowska, A. (2020) The Astrophysical Journal, Volume 899, Issue 2, id.141
- “Constraints on Particles and Fields from Full Stokes Observations of AGN” by Homan, Daniel, Hovatta, Talvikki, Kovalev, Yuri, Lister, Matthew, Pushkarev, Alexander & Savolainen, Tuomas (2018) Galaxies, vol. 6, issue 1, p. 17
“MOJAVE XII: Acceleration and Collimation of Blazar Jets on Parsec Scales” by Homan, D. C., Lister, M. L., Kovalev, Y. Y., Pushkarev, A. B., Savolainen, T., Kellermann, K. I., Richards, J. L., and Ros, E. (2015) The Astrophysical Journal, Volume 798, Issue 2, article id. 134, 16 pp.
Other
- National Science Foundation RUI Research Grant (2007-2011)
- Cottrell College Science Award from Research Corporation (2005-2007)
- NASA Graduate Student Research Fellowship (1996-1999)
