Professor Koushiappas works in the interface between cosmology and particle physics. His work is predominantly in the area of dark matter physics and the search for the nature of the dark matter particle from an experimentally-motivated theoretical perspective. He is interested in the effects of the dark matter particle properties (mass, couplings) to the large-scale structure of the universe, the disentanglement of diffuse high-energy astrophysical backgrounds in the context of dark matter searches, as well as new statistical approaches to a wide variety of problems. He also maintain interests in classical astrophysical problems and has also made contributions in the fields of galaxy formation, gravitational lensing and gravitational waves. He joined Brown University in the summer of 2008. Before that he was a postdoctoral researcher in the Theoretical Division at Los Alamos National Laboratory, and prior to that he was a postdoctoral researcher in the Department of Physics at ETH-Zurich (Swiss Federal Institute of Technology). He received his Ph.D. from The Ohio State University in 2004.
| Vattis, Kyriakos, Koushiappas, Savvas M., Loeb, Abraham. "Dark matter decaying in the late Universe can relieve the H0 tension." Physical Review D, vol. 99, no. 12, 2019. |
| Vattis, Kyriakos, Koushiappas, Savvas M. "Self-interacting dark matter constraints in a thick dark disk scenario." Physical Review D, vol. 97, no. 10, 2018. |
| Koushiappas, Savvas M., Loeb, Abraham. "Dynamics of Dwarf Galaxies Disfavor Stellar-Mass Black Holes as Dark Matter." Physical Review Letters, vol. 119, no. 4, 2017. |
| Koushiappas, Savvas M., Loeb, Abraham. "Maximum Redshift of Gravitational Wave Merger Events." Physical Review Letters, vol. 119, no. 22, 2017. |
| Blackadder, Gordon, Koushiappas, Savvas M. "Cosmological constraints to dark matter with two- and many-body decays." Physical Review D, vol. 93, no. 2, 2016. |
| Geringer-Sameth, Alex, Koushiappas, Savvas M., Walker, Matthew G. "Comprehensive search for dark matter annihilation in dwarf galaxies." Physical Review D, vol. 91, no. 8, 2015. |
| Bonnivard, Vincent, Combet, Céline, Maurin, David, Geringer-Sameth, Alex, Koushiappas, Savvas M., Walker, Matthew G., Mateo, Mario, Olszewski, Edward W., Bailey III, John I. "DARK MATTER ANNIHILATION AND DECAY PROFILES FOR THE RETICULUM II DWARF SPHEROIDAL GALAXY." ApJ, vol. 808, no. 2, 2015, pp. L36. |
| Geringer-Sameth, Alex, Koushiappas, Savvas M., Walker, Matthew. "DWARF GALAXY ANNIHILATION AND DECAY EMISSION PROFILES FOR DARK MATTER EXPERIMENTS." ApJ, vol. 801, no. 2, 2015, pp. 74. |
| Geringer-Sameth, Alex, Walker, Matthew G., Koushiappas, Savvas M., Koposov, Sergey E., Belokurov, Vasily, Torrealba, Gabriel, Evans, N. Wyn. "Indication of Gamma-Ray Emission from the Newly Discovered Dwarf Galaxy Reticulum II." Phys. Rev. Lett., vol. 115, no. 8, 2015. |
| Blackadder, Gordon, Koushiappas, Savvas M. "Dark matter with two- and many-body decays and supernovae type Ia." Physical Review D, vol. 90, no. 10, 2014. |
| Geringer-Sameth, Alex, Koushiappas, Savvas M. "Dark matter line search using a joint analysis of dwarf galaxies with the Fermi Gamma-ray Space Telescope." Physical Review D, vol. 86, no. 2, 2012. |
| Geringer-Sameth, Alex, Koushiappas, Savvas M. "Detecting unresolved moving sources in a diffuse background." Monthly Notices of the Royal Astronomical Society, vol. 425, no. 2, 2012, pp. 862-877. |
| Geringer-Sameth, Alex, Koushiappas, Savvas M. "Extracting the unresolved pulsar contribution to the gamma-ray background." Monthly Notices of the Royal Astronomical Society, vol. 421, no. 2, 2012, pp. 1813-1824. |
| Geringer-Sameth, Alex, Koushiappas, Savvas M. "Exclusion of Canonical Weakly Interacting Massive Particles by Joint Analysis of Milky Way Dwarf Galaxies with Data from the Fermi Gamma-Ray Space Telescope." Phys. Rev. Lett., vol. 107, no. 24, 2011. |
| Reed, Darren S., Koushiappas, Savvas M., Gao, Liang. "Non-universality of halo profiles and implications for dark matter experiments." Monthly Notices of the Royal Astronomical Society, vol. 415, no. 4, 2011, pp. 3177-3188. |
| Chen, Jacqueline, Koushiappas, Savvas M., Zentner, Andrew R. "THE EFFECTS OF HALO-TO-HALO VARIATION ON SUBSTRUCTURE LENSING." ApJ, vol. 741, no. 2, 2011, pp. 117. |
| Baxter, Eric J., Dodelson, Scott, Koushiappas, Savvas M., Strigari, Louis E. "Constraining dark matter in galactic substructure." Physical Review D, vol. 82, no. 12, 2010. |
| Koushiappas, Savvas M., Zentner, Andrew R., Kravtsov, Andrey V. "Distribution of annihilation luminosities in dark matter substructure." Physical Review D, vol. 82, no. 8, 2010. |
| Kamionkowski, Marc, Koushiappas, Savvas M., Kuhlen, Michael. "Galactic substructure and dark-matter annihilation in the Milky Way halo." Physical Review D, vol. 81, no. 4, 2010. |
| Chen, Jacqueline, Koushiappas, Savvas M. "GRAVITATIONAL NANOLENSING FROM SUBSOLAR MASS DARK MATTER HALOS." ApJ, vol. 724, no. 1, 2010, pp. 400-410. |
| Koushiappas, Savvas M., Kamionkowski, Marc. "Galactic Substructure and Energetic Neutrinos from the Sun and Earth." Phys. Rev. Lett., vol. 103, no. 12, 2009. |
| Koushiappas, Savvas M. "The detection of subsolar mass dark matter halos." New Journal of Physics, vol. 11, no. 10, 2009, pp. 105012. |
| Ando, Shin’ichiro, Kamionkowski, Marc, Lee, Samuel K., Koushiappas, Savvas M. "Can proper motions of dark-matter subhalos be detected?." Physical Review D, vol. 78, no. 10, 2008. |
| Kamionkowski, Marc, Koushiappas, Savvas M. "Galactic substructure and direct detection of dark matter." Physical Review D, vol. 77, no. 10, 2008. |
| Strigari, Louis E., Koushiappas, Savvas M., Bullock, James S., Kaplinghat, Manoj, Simon, Joshua D., Geha, Marla, Willman, Beth. "The Most Dark‐Matter–dominated Galaxies: Predicted Gamma‐Ray Signals from the Faintest Milky Way Dwarfs." ApJ, vol. 678, no. 2, 2008, pp. 614-620. |
| Miniati, Francesco, Koushiappas, Savvas M., Di Matteo, Tiziana. "Angular Anisotropies in the Cosmic Gamma-Ray Background as a Probe of Its Origin." ApJ, vol. 667, no. 1, 2007, pp. L1-L4. |
| Abazajian, Kevork N., Markevitch, Maxim, Koushiappas, Savvas M., Hickox, Ryan C. "Limits on the radiative decay of sterile neutrino dark matter from the unresolved cosmic and soft x-ray backgrounds." Physical Review D, vol. 75, no. 6, 2007. |
| Strigari, Louis E., Koushiappas, Savvas M., Bullock, James S., Kaplinghat, Manoj. "Precise constraints on the dark matter content of Milky Way dwarf galaxies for gamma-ray experiments." Physical Review D, vol. 75, no. 8, 2007. |
| Abazajian, Kevork, Koushiappas, Savvas M. "Constraints on sterile neutrino dark matter." Physical Review D, vol. 74, no. 2, 2006. |
| Koushiappas, Savvas M. "Proper Motion of Gamma Rays from Microhalo Sources." Phys. Rev. Lett., vol. 97, no. 19, 2006. |
| Koushiappas, Savvas M., Zentner, Andrew R. "Testing Models of Supermassive Black Hole Seed Formation through Gravity Waves." ApJ, vol. 639, no. 1, 2006, pp. 7-22. |
| ZENTNER, A. R., KOUSHIAPPAS, S. M., KAZANTZIDIS, S. "DARK MATTER HALOS: SHAPES, THE SUBSTRUCTURE CRISIS, AND INDIRECT DETECTION." The Identification of Dark Matter, 2005. |
| Koushiappas, Savvas M., Bullock, James S., Dekel, Avishai. "Massive black hole seeds from low angular momentum material." Monthly Notices of the Royal Astronomical Society, vol. 354, no. 1, 2004, pp. 292-304. |
| Koushiappas, Savvas M., Zentner, Andrew R., Walker, Terrence P. "Observability of gamma rays from neutralino annihilations in the Milky Way substructure." Physical Review D, vol. 69, no. 4, 2004. |
| Year | Degree | Institution |
|---|---|---|
| 2004 | PhD | Ohio State University |
| 1998 | BS | University of New Mexico |
Department of Energy, Office of High Energy Physics, 2017-2019
National Science Foundation, Division of Physics (Theoretial Physics), 2014-2017
NASA Fermi Guest Investigator, 2013-2015
Department of Energy, Office of High Energy Physics, 2012-2015
NASA EPSCoR-RID, 2012
Richard B. Salomon Award, 2012-2013
National Science Foundation, Division of Physics (Theoretical Physics), 2010-2013
Leon Heller Publication Prize Award (Los Alamos National Laboratory), 2008
| PHYS 0040 - Basic Physics B |
| PHYS 0470 - Electricity and Magnetism |
| PHYS 0500 - Advanced Classical Mechanics |
| PHYS 1250 - Stellar Structure and the Interstellar Medium |
| PHYS 1280 - Introduction to Cosmology |
| PHYS 1510 - Advanced Electromagnetic Theory |
| PHYS 2280 - Astrophysics and Cosmology |
