Stars in the universe are organized into galaxies that often include many billions of stars. Galaxies have many additional components, including hot, warm, and cool diffuse gas, cold gas clouds, extended halos of dark matter and, sometimes, central supermassive black holes. X-rays may be emitted from interstellar gas that is hotter than a million degrees Kelvin, by individual supernova remnants and X-ray binaries that are part of the stellar population, and by gas falling into the central black hole. The detailed characteristics of these X-ray emitting components are used to study the star formation history, and the evolution and structure of galaxies - including our own Milky Way. Our group studies X-rays from discrete sources and diffuse emission in galaxies near and far in order to understand their origin, evolution, and structure. Many of these researchers belong to a joint research effort based at the NASA/Goddard Space Flight Center, Johns Hopkins University, and CRESST II / University of Maryland (Baltimore County or College Park) studying galaxies across the electromagnetic spectrum (including in X-rays). For updates on the activities of a sub-group of X-ray galaxies research led by Ann Hornschemeier, see

Current Group Members

Selected Research and Presented Papers

  • Hodges-Kluck, E., Bregman, J.N., Li, Jiangtao, 2018, ApJ, 866, 126, The Hot, Accreted Halo of NGC 891 (NASA ADS)

  • Vulic, N., Hornschemeier, A. E., Wik, D. R., et al., 2018, ApJ, 861, 150, Black Holes and Neutron Stars in Nearby Galaxies: Insights from NuSTAR (NASA ADS)

  • Ogorzalek, A., Zhuravleva, I., Allen, S. W., Pinto, C., Werner, N., Mantz, A. B., Canning, R. E. A., Fabian, A. C., Kaastra, J. S., and de Plaa, J. 2017, MNRAS, 472, 1659, Improved measurements of turbulence in the hot gaseous atmospheres of nearby giant elliptical galaxies (NASA ADS)

  • Hodges-Kluck, E., Cafmeyer, J., Bregman, J.N., 2016, ApJ, 833, 58, Ultraviolet Halos Around Spiral Galaxies. I. Morphology (NASA ADS)

  • Hodges-Kluck, E., Miller, M.J., Bregman, J.N., 2016, ApJ, 822, 21, The Rotation of the Hot Gas around the Milky Way (NASA ADS)

  • Basu-Zych, A. R., Lehmer, B., Fragos, T., et al., 2016, ApJ, 818, 140, Exploring the Overabundance of ULXs in Metal- and Dust-poor Local Lyman Break Analogs, (NASA ADS)

  • Tzanavaris, P., Hornschemeier, A. E., Gallagher, S. C., et al., 2016, ApJ, 817, 95, Exploring X-Ray Binary Populations in Compact Group Galaxies with Chandra, (NASA ADS)

  • Basu-Zych, A. R., Lehmer, B. D., Hornschemeier, A. E., et al., 2013, ApJ, 774, 152, Evidence for Elevated X-ray Emission in Local Lyman Break Galaxy Analogs, (NASA ADS)

  • Tzanavaris, P., Fragos, T., Tremmel, M., Jenkins, L., et al., 2013, ApJ, 774, 136, Modeling X-ray Binary Evolution in Normal Galaxies: Insights from SINGS (NASA ADS)

  • Basu-Zych, A. R., Lehmer, B. D., Hornschemeier, A. E., et al., 2013, ApJ, 762, 45, The X-Ray Star Formation Story as Told by Lyman Break Galaxies in the 4 Ms CDF-S, (NASA ADS)

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