Testing Homogeneity with Galaxy Star Formation Histories

Understand

Observationally confirming spatial homogeneity on sufficiently large cosmological scales is of importance to test one of the underpinning assumptions of cosmology, and is also imperative for correctly interpreting dark energy.

• A challenging aspect of this is that homogeneity must be probed inside our past lightcone, while observations take place on the lightcone.
• The star formation history (SFH) in the galaxy fossil record provides a novel way to do this.
• We calculate the SFH of stacked Luminous Red Galaxy (LRG) spectra obtained from the Sloan Digital Sky Survey.