The Fate of the First Galaxies. III. Properties of Primordial Dwarf Galaxies and their Impact on the Intergalactic Medium
| dc.creator | Ricotti, Massimo | |
| dc.creator | Gnedin, Nickolay Y. | |
| dc.creator | Shull, J. Michael | |
| dc.date | 2008-02-19 | |
| dc.date.accessioned | 2026-07-07T11:56:11Z | |
| dc.date.available | 2026-07-07T11:56:11Z | |
| dc.description | In two previous papers, we presented simulations of the first galaxies in a representative volume of the Universe. The simulations are unique because we model feedback-regulated galaxy formation, using time-dependent, spatially-inhomogeneous radiative transfer coupled to hydrodynamics. Here, we study the properties of simulated primordial dwarf galaxies with masses <2x10^8 Msolar and investigate their impact on the intergalactic medium. While many primordial galaxies are dark, about 100--500 per comoving Mpc^3 are luminous but relatively faint. They form preferentially in chain structures, and have low surface brightness stellar spheroids extending to 20% of the virial radius. Their interstellar medium has mean density n_H~10--100 cm^-3, metallicity Z~ 0.01--0.1 Zsolar and can sustain a multi-phase structure. With large scatter, the mean efficiency of star formation scales with halo mass, <f_*> \propto M_dm^2, independent of redshift. Because of feedback, halos smaller than a critical mass, M_crit(z), are devoid of most of their baryons. More interestingly, we find that dark halos have always a smaller M_crit(z) than luminous ones. Metal enrichment of the intergalactic medium is inhomogeneous, with only a 1%--10% volume filling factor of enriched gas with [Z/H]>-3.0 and 10%--50% with [Z/H]>-5.0. At z=10, the fraction of stars with metallicity Z<10^-3 Zsolar is 10^-6 of the total stellar mass. Although detections of high-redshift dwarf galaxies with the James Webb Space Telescope will be a challenge, studies of their fossil records in the local Universe are promising because of their large spatial density. | |
| dc.description | 19 pages, 13 figures, 2 tables (emulateapj). Submitted to ApJ | |
| dc.identifier | https://arxiv.org/abs/0802.2715 | |
| dc.identifier | http://arxiv.org/abs/0802.2715 | |
| dc.identifier | Astrophys.J.685:21-39,2008 | |
| dc.identifier | doi:10.1086/590901 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/205497 | |
| dc.subject | Astrophysics | |
| dc.title | The Fate of the First Galaxies. III. Properties of Primordial Dwarf Galaxies and their Impact on the Intergalactic Medium | |
| dc.type | text |