Sarah Gallagher, Professor

Sarah Gallagher

Contact Information

Office: PAB 205
Tel: (519) 661-2111 x86707

Personal web page 

Research Areas

Active Galaxies
Black Holes 
Compact Groups of Galaxies

Research Interests

I am an extragalactic astronomer with an inclusive attitude towards the electromagnetic spectrum. I've used observations from the radio through the X-ray to study quasars (actively growing supermassive black holes) and compact galaxy groups. The growing black holes powering quasars are found in the centres of distant galaxies, and a quasar can outshine all of the stars in its galaxy a thousand times over. While they are growing, quasars often also spew out material at high speeds in energetic winds. My research focusses on understanding the relationship between black hole growth and winds, the properties of these winds, and their interactions with their host galaxies. A compact galaxy group comprises a handful of large galaxies within a few galaxy radii of eachother. As a result, the galaxies undergo repeated gravitational encounters that alter their shapes and star formation histories over time. In addition to being spectacularly beautiful, this unusual environment allows our team to study how cold gas - the fuel for star formation - is processed while being pushed and pulled by multiple galaxies in close proximity.



  1. Lenkic, Tzanavaris, Gallagher et al. 2016 "The ultraviolet and infrared star formation rates of compact group galaxies: an expanded sample,” MNRAS, 459, 2948
  2. Tammour, Gallagher et al. 2016 "Insights into quasar UV spectra using unsupervised clustering analysis” MNRAS, 459, 1659
  3. Gallagher et al. 2015, "Investigating the structure of the windy torus in quasars,” MNRAS, 451, 2991
  4. Fedotov, Gallagher, et al. 2015, "A comprehensive HST BVI catalogue of star clusters in five Hickson compact groups of galaxies,” MNRAS, 449, 2937
  5. Tammour, Gallagher, et al. 2015, "Tracing quasar narrow-line regions across redshift: a library of high-S/N optical spectra,” MNRAS, 448, 3354
  6. Desjardins, Gallagher, et al. 2006, "Some Like It Hot: Linking Diffuse X-Ray Luminosity, Baryonic Mass, and Star Formation Rate in Compact Groups of Galaxies,” ApJ, 790, 132
  7. Vulic, Gallagher, & Barmby 2014,  "Faint X-Ray Binaries and their Optical Counterparts in M31,” ApJ, 790, 136

[Complete Publications Listing]


Physics 1502: Enriched Introductory Physics II
Astronomy 1021: General Astronomy
Physics 1302: Introductory Physics II
Physics 1402: Physics for Engineering Students II
Astronomy 3302A: The Interstellar MediumAstronomy 2801: Stars, Galaxies, and Cosmology

Astronomy 9606: Radiative Processes in Astrophysics
Astronomy 9608: Extragalactic Astronomy 


  • Faculty Scholar Award 2016-2018
  • Faculty of Science Outreach Award, 2010
  • Ontario Ministry of Research & Innovation Early Researcher Award, 2010-2014
  • International Union of Pure and Applied Physics Commission on Astrophysics Young Physicist Prize (Honorable Mention), 2008
  • Spitzer Fellowship, 2003-2006

Professional Activities

  • Science Advisor to the President, Canadian Space Agency, Oct 2018-Sept 2022
  • Mauna Kea Spectroscopic Explorer Science Team, member, 2014-present
  • Joint Committee on Space Astronomy, member, 2015-2017
  • Canadian Astronomical Society (CASCA) Board, Directory, 2014-2017
  • Canadian Time Allocation Committee (CanTAC), chair, 2013-2014, member, 2011-2014
  • Space Telescope User's Committee, 2009-2011
  • Local Organizing Committee, CASCA 2011, co-chair, 2011
  • Canadian Astronomical Society (CASCA), full member
  • American Astronomical Society (AAS), full member