Red population of Abell 1314 : A rest-frame narrowband photometric evolutionary analysis

Yuvraj Harsha Sreedhar1,*
1University of Vienna, Institute of Astronomy, Türkenschanzstraße 17, A-1180 Vienna, Austria

Received: April 24 2014 | Accepted: September 30 2014

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Red sequence galaxies form with an intense burst of star formation in the early universe to evolve passively into massive, metal rich, old galaxies at z ~ 0. But Abell 1314 (z=0.034) is found to host almost all red sequence galaxy members – identified using the mz index, classified using the Principle Component Analysis technique and SDSS colour correlations – some of which show properties of low-mass, star forming, and metal rich galaxies. The variably spread Intra-Cluster Medium (ICM) near the core forms a vital part in influencing the evolution of these members. To study their evolution, I correlated di erent parameters of the rest-frame narrowband photometry and the derived luminosity-weighted mean Single Stellar Population model ages and metallicities.

The study finds the member galaxies evolve di erently in three di erent sections of the cluster: 1. the region of ≤ 200 kpc hosts passively evolving old, massive systems which accumulate mass by dry, minor mergers, 2. the zone between 200-500 kpc shows stripped systems (or in the process of being gas stripped) by ram pressure with moderate star formation history, 3. the outer regions (≤ 500 kpc) show low-mass red objects with blue, star forming Butcher-Oemler galaxy like colours. This sort of environmental condition is known to harbour hybrid systems, like, the pseudo bulges, blue sequence E/S0 and Butcher-Oemler like satellite cluster galaxies. Overall, the cluster is found to be poor, quiescent with galaxies to have formed by the monolithic structure formation in the early universe and are now evolving with mergers and gas stripping processes by ram pressure.

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Keywords : galaxies: formation – galaxies: evolution – galaxies: clusters: individual: A1314 – galaxies: fundamental parameters (classification, colours, luminosities, masses, radii, etc.) – galaxies: interactions – galaxies: photometry