Nick Gnedin The Brief History of Time End of inflation: Today: - PowerPoint PPT Presentation

Faintest Galaxies in the JWST Era Nick Gnedin

The Brief History of Time End of inflation: Today: z=10 27 z=0 t=10 -36 s t=13.7 Gyr

The Brief History of Time ionized neutral ionized RE-IONIZATION

What We Know Now : Galaxy Luminosity Functions  Data (may) exist all the way to z =10 and M UV =-13. = -2.5 log 10 (L * )+5 10 8 L  10 6 L  Livermore+ 2016 Bouwens+2015

What We Know Now : Galaxy Luminosity Functions  High redshift galaxies are not particularly glaring.  The faintest ones are detected with the help of gravitational lensing in HST Frontier Fields.

The Flood Is Coming: JWST  James Webb Space Telescope (JWST) is the primary NASA mission for the next decade. Launch date: 2021? Destination: L2 Mirror: 6 meters

The Flood Is Coming: JWST  Studying reionization sources is the primary science goal of JWST.  It will perform a range of surveys of varying depth, greatly improving Covered with lensing precision of luminosity functions, as well as studying individual galaxies. -25 -15 -13 Mason+ 2015

The Flood Is Coming  Reionization research is on the brink of a major breakthrough(s). Forthcoming observations will make all existing models obsolete.  Hence, theorists’ task is not to make more models now, but rather to develop new modeling technology.  And it is happening: • DRAGONS • Aurora • Emma • Cosmic Dawn • Renaissance Simulations • CRASH • SPHINX • CROC

The Flood Is Coming  One (typical) example in action:  Disclaimer: other projects/efforts are achieving similar overall levels of computational scale, agreement with data, etc.

Simulating Reionization: Physics  Dark matter  Gas dynamics  Atomic processes  Radiative transfer  Star formation & stellar feedback

Simulating Reionization: Physics  Star formation & stellar feedback are modeled as a sub-grid recipe . We are not starting from scratch, just using what is shown to work by low-z projects (Illustris, EAGLE, NIHAO, MUFASA, …).

Simulating Reionization: Scales  Capturing most of star-forming galaxies requires boxes ~ 50-100 Mpc (comoving).  Resolving star formation requires resolution ~100-200 pc (depends on your sub-grid model).  Resolving all star-forming galaxies requires mass resolution of about 10 6 M  .  Conclusion: we need simulations with  spatial dynamic range L/ ∆ x ~ 100,000  mass dynamic range M box /M cell ~ 10 billion

Moore’s Law REIONIZATION Doubling in speed every 13 months

Simulating Reionization: CROC on Blue Waters Box size: 120 Mpc Resolution: 100 pc

CROC in Blue Waters

The CROC Project: Convergence Study Mass 10 17 M  10 7 M  10 6 M  Space 100 pc 60 Mpc 120 Mpc

The CROC Project: Success  Galaxies (and many other things) are ok!

The Role of JWST: There Will Be Blood!  All simulation agree with the data where the data exist.  They all disagree (for a good reason!) strongly JWST in the regime that JWST will probe.  JWST will kill most (or all) existing models.

Take Aw ay Points  Models will not die in vain – they differ for physical reasons, encapsulating our ignorance of star formation and stellar feedback.  JWST measurements will strongly constraint such models, telling us important information about “sub-grid” processes (for example, whether stars can form in atomic gas).  We are entering a golden age of reionization studies, with observations and theory in good balance to ensure rapid progress.  Lots of fun ahead…

The End