School of
Astronomy (SoA) - Weekly Seminar
Fundamental
and Photometric Plane of dwarf galaxies in Coma
Ehsan Kourkchi (SUT and IPM)
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 R-band
luminosity of -15 Magnitudes.
Deimos with sampling rate of 0.3 Angstrom per pixel and
FWHM resolution of 1.6 Angstrom is suitable for
observations of very faint dwarf galaxies and small
velocity dispersions. It enables us to
measure the velocity dispersions down to ~10 km/s for
the wavelength range between 7500 to 10,000 Angstrom.
Calcium triplet lines in this range allow us to obtain
the velocity dispersion for the sample
galaxies with high precision. We also performed a
comprehensive error analysis to better estimate the
uncertainties of this key observable.
We also carried out a galaxy structure modeling using
the 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 dwarf
galaxies and their deviations from the fundamental plane
increases as their luminosities, central
velocity dispersions and Sersic 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 Sersic model. Photometric plane for
the sample galaxies shows reduced scatter around the
plane at the faint end, in comparison to the same in the
fundamental plane
Wednesday
/ 12-May-2010 / 22-Ordibehesht-1389/ 2:00 PM
IPM
Larak Building, School of Astronomy
Address:
Larak Garden,
opposite Araj, Artesh Highway,Tehran, Iran
E-mail:
astro(at)ipm.ir
