Oral Presentation
Constraining the distribution of cosmic baryons from FLIMFLAM survey
Presenter: Khrykin Ilya (Kavli IPMU)
The 'Missing Baryon Problem' has been resolved thanks to recent samples of localized fast radio bursts (FRBs) with measured redshifts, but major questions remain regarding the relative distribution of cosmic baryons in the diffuse IGM vs galactic halos, and the extent of the latter, with implications for galaxy formation and feedback models. Constraining the relative cosmic baryon distribution, however, is challenging due to the large cosmic variance in the line-of-sight baryon distribution at fixed FRB redshift due to the cosmic web as well as individual intervening galaxy haloes. I will show that this issue can be mitigated by measuring the spectroscopic redshift distribution of foreground galaxies in front of localized FRBs in order to map out the cosmic web as well as characterize intervening galactic halos. I will describe FLIMFLAM, an ongoing 40-night spectroscopic survey on the Anglo-Australian Telescope (and other facilities) that will map the foregrounds of ~20-30 localized FRBs primarily detected by CRAFT/ASKAP and localized by the F^4 collaboration. FLIMFLAM will provide the first direct constraints on the relative partition of baryons in the CGM and IGM, as well as on the characteristic sizes of galaxy CGM halos. Using the MCMC algorithm, we predict that a sample of 30 FRBs will be enough to constrain the fraction of cosmic baryons in the IGM/CGM to unprecedented precision of ~5-10%.
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