Physics colloquium

Date
Tue, May 5, 2026 3:30 pm - 4:30 pm
Location
1410 Toll Building

Description

Paul Martini, Professor of Astronomy, The Ohio State University 

Title: Cosmology with Large Spectroscopic Surveys

Large scale spectroscopic surveys provide unique information that addresses many fundamental questions in physics, especially the nature of cosmic acceleration or dark energy, dark matter, and primordial inflation. The Dark Energy Spectroscopic Instrument (DESI) collaboration has released new cosmological results based on over 14 million extragalactic objects with 0.1 < z < 4.2 from the first three years of survey operations. We have used this dataset to measure Baryon Acoustic Oscillations (BAO) to determine the transverse comoving distance and Hubble expansion rate, as well as combined these results with other datasets to explore extensions to the standard flat LCDM cosmological model and obtain constraints on the sum of neutrino masses. I will describe the design and implementation of the DESI survey and summarize the recent cosmology results, with a particular focus on the Lyman Alpha forest measurement at z > 2. The collaboration now has nearly five years of data in hand, and I will discuss the plans for this analysis and forecasts for DESI results with the data we plan to obtain through the end of 2028. Several future surveys that would start after 2028 are in active development, and I will conclude with a brief motivation for these new surveys and the technology development underway to meet their goals.


Host: Drew Baden