Cosmology and Astrophysics with cosmic neutral hydrogen

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 Time:  Friday, January 18, 2019, 09:00am
 Title:  Cosmology and Astrophysics with cosmic neutral hydrogen
 Speaker:  Dr. Francisco Villaescusa-Navarro (Flatiron Institute)



I will discuss the advantages of observing the Universe through 21cm intensity mapping. I will point out that in order to extract the maximum cosmological and astrophysical information from 21cm surveys such as Tianlai, FAST, and SKA, accurate theoretical predictions for the distribution of the cosmic signal are needed. I will present the limitations of using linear theory to achieve that, and will show how we can use state-of-the-art magneto-hydrodynamic simulations to model the distribution of HI from linear to fully non-linear scales. I will show the most sophisticated, and computationally expensive, 21cm maps created to-date, and present the ingredients needed to reproduce them without running expensive hydrodynamic simulations. I will show how 21cm observations can be used to learn about the efficiency of astrophysical processes and to constrain the nature of dark matter and the sum of the neutrino masses. I will present results from simulations that contain the cosmological signal, system noise and foregrounds, to show how well we can determine the position of the BAO peak with SKA.

I am a Flatiron Research Fellow at the new Center for Computational Astrophysics in New York City. I work on a large variety of topics of large-scale structure such as 21cm intensity mapping, cosmic neutrinos, galaxy clustering, cosmic voids, redshift-space distortions, the Lya-forest, and modified gravity. I am an expert on computational cosmology. I am the author of the HADES simulations, a suite of more than 1000 N-body and hydrodynamic simulations with massive and massless neutrinos. I have recently developed the Quijote simulations, a set of 23000 N-body simulations, containing more than 3.3 trillions of particles at a single redshift, designed to quantify the information content on cosmological observables. I co-lead the Square Kilometre Array cosmological simulations working group. I am also the co-leader of the cosmological probes focused group of the Simulating Multi-Scale Astrophysics to Understand Galaxies Consortium (SMAUG) international collaboration. Before coming to New York, I was a cosmoIGM fellow at the Trieste Observatory in Italy. I did my Ph.D. between the University of Valencia in Spain and Harvard University.

Host: Prof. Yi Mao

Slides: 20190118-Navarro.pdf