- Title
- LyC escape from SPHINX galaxies in the Epoch of Reionization
- Date
- 2022.08.17
- Writer
- 천문우주학과
- 게시글 내용
-
LyC escape from SPHINX galaxies in the Epoch of Reionization
Joakim Rosdahl, Jérémy Blaizot, Harley Katz, Taysun Kimm, Thibault Garel, Martin Haehnelt, Laura C. Keating, Sergion Martin-Alvarez, Léo Michel-Dansac, Pierre Ocvirk
We measure escape fractions, fesc, of ionizing radiation from galaxies in the SPHINX suite of cosmological radiation-hydrodynamical simulations of reionization, resolving halos with Mvir⪆7.5×107 M⊙ with a minimum cell width of ≈10 pc. Our new and largest 20 co-moving Mpc wide volume contains tens of thousands of star-forming galaxies with halo masses up to a few times 1011 M⊙. The simulated galaxies agree well with observational constraints of the UV luminosity function in the Epoch of Reionization. The escape fraction fluctuates strongly in individual galaxies over timescales of a few Myrs, due to its regulation by supernova and radiation feedback, and at any given time a tiny fraction of star-forming galaxies emits a large fraction of the ionizing radiation escaping into the inter-galactic medium. Statistically, fesc peaks in intermediate-mass, intermediate-brightness, and low-metallicity galaxies (M∗≈107 M⊙, M1500≈−17, Z≲5×10−3 Z⊙), dropping strongly for lower and higher masses, brighter and dimmer galaxies, and more metal-rich galaxies. The escape fraction correlates positively with both the short-term and long-term specific star formation rate. According to SPHINX, galaxies too dim to be yet observed, with M1500⪆−17, provide about 55 percent of the photons contributing to reionization. The global averaged fesc naturally decreases with decreasing redshift, as predicted by UV background models and low-redshift observations. This evolution is driven by decreasing specific star formation rates over cosmic time.
- 저자명
- Taysun Kimm