ASTRO SEMINAR

The speaker will be Prof. Avishai Dekel

Place: Holcblat Hall

Time: Wednesday, 30/Apr/2003, 14:00

Title: Feedback to the Rescue of Galaxy Formation in CDM Cosmology

Abstract Galaxy formation theory within the CDM paradigm faces several difficulties such as the cusp/core discrepancy, the angular-momentum loss, and the missing dwarfs. These problems are modeled in simple terms within the merger picture and a common solution is proposed: feedback effects from supernovae and background radiation. In particular, new data from SDSS and the Local Group refine the scaling relations obeyed by LSB/dwarf galaxies over a range of 5 decades in stellar mass (representing 95% of the galaxies). A simple model of supernova feedback naturally recovers these relations and explains the distinction between LSB and bright galaxies, indicating that the feedback effects have a primary role in determining the galaxy properties along the LSB sequence. Radiative feedback is more effective than previously thought -- it may explain dark mini-haloes with no luminous component and the distinction between dwarf spheroidals and irregulars.