Dynamical and Photometric Properties of Dwarf Galaxies in Coma Cluster

¹ School of Astronomy, Institute for Research in Fundamental Sciences (IPM), PO Box 19395-5531, Tehran, Iran
² Department of Physics, Sharif University of Technology, PO Box 11155-9161, Tehran, Iran
³ Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead CH41 1LD, UK
⁴ Institute for Astronomy, Univ. of Hawaii, 2680 Woodlawn Dr., Honolulu, HI 96821, USA
⁵ Gemini Observatory, Northern Operations Center, 670 N. A’ohoku Place, Hilo, Hawaii, 96720, USA

e-mail: ehsan@ipm.ir

Abstract

We study the fundamental and the photometric plane of a sample of ~50 dwarf galaxies within the core of Coma cluster observed with DEIMOS on Keck II down to M_R ~−15 Mag. We also carried out a galaxy structure modeling using the HST/ACS I-band images for a larger sample. We found larger velocity dispersions for fainter dwarfs than what expected from mass-luminosity trends of brighter Coma galaxies. In addition, fainter galaxies do not lie on the fundamental plane of brighter dwarfs and their deviations from the fundamental plane increases as their luminosities, central velocity dispersions and Sérsic indices decrease. We also noticed that those faint galaxies, which are outliers in the fundamental plane relation, have excess light at their central region with respect to their corresponding Sérsic model.