Galaxy Systems and Large Scale Structures

Halo-Galaxy Connection

The nature of the connection between the dark matter halos and their constituent galaxies is still unknown. To test various hypothesis we study galaxy groups and clusters. Galaxy groups and clusters are important for understanding galaxy evolution as well as structure formation. With a relatively lower velocities of galaxies in groups compared to clusters of galaxies, different mechanisms are likely to act in groups, e.g. more efficient mergers, than in clusters, e.g. ram pressure stripping and harassments, driven by relatively large velocities of galaxies in higher density Inter-galactic medium (IGM). Galaxy mergers and group scale mergers can influence the properties of galaxies, Star formation and the AGN as well as the IGM properties.

IPM staff involved: H. Khosroshahi, Amin Farhang, Mohammad Hossein Zholideh, Amirnezam Amiri

In collaboration with: Mojtaba Raouf (KASI, Korea), Ghassem Gozaliasl (Helsinki)

Fossil groups

Galaxy groups are in the spotlight, due to their suspected role in formation of massive galaxies. We are a leading research group on studies of fossil galaxy groups, evidently early formed groups with distinct halo, galaxy, IGM and AGN properties. We study various aspects of these groups and their galaxies in optical, radio, X-ray as well as the internal kinematic of their most luminous galaxies. We use cosmological simulations and observations to advance this research field. The research follows the pioneering work of the researchers at the University of Birmingham following the discovery of the first fossil galaxy groups by Ponman et al, 1994.

IPM staff involved: H. Khosroshahi, Amin Farhang, Mohammad Hossein Zholideh

In collaboration with: Mojtaba Raouf (KASI, Korea), Ghassem Gozaliasl (Helsinki), Gary Mamon (IAP), Alexis Finoguenov (Helsinki), Ali Dariush (IoA, Cambridge)

GAMA Project

GAMA is a project to exploit the latest generation of ground-based and space-borne survey facilities to study cosmology and galaxy formation and evolution.

At the heart of this project lies the GAMA spectroscopic survey of ~300,000 galaxies down to r < 19.8 mag over ~286 deg sq, carried out using the AAOmega multi-object spectrograph on the Anglo-Australian Telescope (AAT) by the GAMA team. This project was awarded 210 nights over 7 years (2008–2014) and the observations are now completed. This survey builds on, and is augmented by, previous spectroscopic surveys such as the Sloan Digital Sky Survey (SDSS), the 2dF Galaxy Redshift Survey (2dFGRS) and the Millennium Galaxy Catalogue (MGC).

IPM staff involved: H. Khosroshahi, Amirnezam Amiri

In collaboration with: Mojtaba Raouf (KASI, Korea), GAMA TEAM