ﻻ يوجد ملخص باللغة العربية
We investigate the radiative transport of dust in primordial galaxies in the presence of the UV radiation field from the first metal-free stars. We find that dust created in the first supernova (SN) explosions can be driven through the interior of the SN remnant to accumulate in the SN shells, where second-generation stars may form from compressed cooling gas. This scenario requires metal-free stars to form continuously over timescales of up to 10 Myr, consistent with recent estimates. Silicate and graphite grains, as well as iron-bearing magnetites, are transported to the shells for reasonable parameter assumptions, but their relative yields from primordial SNe is an important factor in the resulting abundance ratios. We compare the results of segregated grain transport with the current nucleosynthetic data on extremely metal-poor Galactic halo stars. Fossil signatures of this process may already have been detected in those iron-poor stars with enhanced carbon and silicate elements such as magnesium, silicon and oxygen. We discuss the implications of our results for the transition from first- to second-generation star formation in primordial galaxies, and the role played by the radiative transport of dust in this process.
We present the results of an observing program with the SCUBA bolometer array to measure the submillimetre (submm) dust continuum emission of 24 distant (z > 1) radio galaxies. We detected submm emission in 12 galaxies with S/N > 3, including 9 detec
We have used the Spitzer Space Telescope to study the dust properties of a sample of star-forming dwarf galaxies. The differences in the mid-infrared spectral energy distributions for these galaxies which, in general, are low metallicity systems, ind
We aim to characterize the relationship between dust properties. We also aim to provide equations to estimate accurate dust properties from limited observational datasets. We assemble a sample of 1,630 nearby (z<0.1) galaxies-over a large range of
We use cosmological simulations to assess how the explosion of the first stars in supernovae (SNe) influences early cosmic history. Specifically, we investigate the impact by SNe on the host systems for Population~III (Pop~III) star formation and exp
When, and how, did the first galaxies and supermassive black holes (SMBH) form, and how did they reionization the Universe? First galaxy formation and cosmic reionization are among the last frontiers in studies of cosmic structure formation. We delin