The current models of galaxy formation and evolution are facing several challenges in the low-mass dark matter haloes regime as they fail to fully explain the properties of dwarf (low-mass and low-luminosity) galaxies as we observe. It is becoming more evident that understanding the nature of dark matter is not possible without gaining a deeper knowledge of dwarf galaxies and the various processes responsible for their properties. Given the diversity of dwarfs, in addition to the observational limits due to their low luminosity, the endeavor towards understanding dwarf galaxies is a tricky assignment. Most of the research on dwarf galaxies in the past has focussed on the detailed properties of nearby systems or the most commonly occurring types of dwarfs. Alternatively, exceptional insight into these objects is gained through studying the most extreme examples.My research engages with the current research on dwarf galaxies to study different phenomena that contribute to their formation and evolution to understand the physics of the dark matter within these systems. In the past few years, I mostly focused on the properties of two classes of extreme dwarf galaxies in galaxy clusters, ultra-compact dwarf galaxies (UCDs) and ultra-diffuse galaxies (UDGs) by means of ground-based and space-based observations. (Image: HST view of UDG Dragonfly44 in the Coma galaxy cluster, credit: T. Saifollahi, NASA/HST)


Implications for galaxy formation models from observations of globular clusters around ultradiffuse galaxies (ADS), Teymoor Saifollahi, Dennis Zaritsky, Ignacio Trujillo, Reynier Peletier, Johan Knapen, Nicola Amorisco, Michael Beasley, Richard Donnerstein, Monthly Notices of the Royal Astronomical Society, 2022

Ultra-compact dwarfs beyond the centre of the Fornax galaxy cluster: hints of UCD formation in low-density environments (ADS), Teymoor Saifollahi, Joachim Janz, Reynier F Peletier, Michele Cantiello, Michael Hilker, Steffen Mieske, Edwin A Valentijn, Aku Venhola, Gijs Verdoes Kleijn, Monthly Notices of the Royal Astronomical Society, 2021

The number of globular clusters around the iconic UDG DF44 is as expected for dwarf galaxies (ADS), Teymoor Saifollahi, Ignacio Trujillo, Michael A Beasley, Reynier F Peletier, Johan H Knapen, Monthly Notices of the Royal Astronomical Society, 2021 (in the media:, Youtube)

All Publications

(PhD Thesis) Understanding the extreme classes of dwarf galaxies (link), Teymoor Saifollahi, University of Groningen, 2022