Roban Kramer

TL;DR: Astropy as discussed by the authors is a Python package for astronomy-related functionality, including support for domain-specific file formats such as flexible image transport system (FITS) files, Virtual Observatory (VO) tables, common ASCII table formats, unit and physical quantity conversions, physical constants specific to astronomy, celestial coordinate and time transformations, world coordinate system (WCS) support, generalized containers for representing gridded as well as tabular data, and a framework for cosmological transformations and conversions.

TL;DR: Astropy as mentioned in this paper provides core astronomy-related functionality to the community, including support for domain-specific file formats such as Flexible Image Transport System (FITS) files, Virtual Observatory (VO) tables, and common ASCII table formats, unit and physical quantity conversions, physical constants specific to astronomy, celestial coordinate and time transformations, world coordinate system (WCS) support, generalized containers for representing gridded as well as tabular data, and a framework for cosmological transformations and conversions.

TL;DR: In this paper, the authors present constrained radiative transfer calculations of Lyα photons propagating through clumpy, dusty, large scale outflows, and explore whether they can quantitatively explain the Lyα halos that have been observed around Lyman Break Galaxies.

Abstract: In the near future, measurements of metal absorption features in the intergalactic medium (IGM) will become an important constraint on models of the formation and evolution of the earliest galaxies, the properties of the first stars, and the reionization and enrichment of the IGM. The first measurement of a metal abundance in the IGM at a redshift approaching the epoch of reionization already offers intriguing hints. Between z = 5:8 and 4:7 (a 0:3 Gyr interval only 1 Gyr after the big bang), the measured density of CIV absorbers in the IGM increased by a factor of � 3:5 (Ryan-Weber et al. 2009; Becker, Rauch & Sargent 2009). If these values prove to be accurate, they pose two puzzles. (1) The total amount of Civ at z = 5:8 implies too little star formation to reionize the IGM by z = 6 or to match the WMAP electron scattering optical depth (�). (2) The rapid growth from z � 6–5 is faster than the buildup of stellar mass or the increase in the star formation rate density over the same interval. We show that a delay of � 0:5–0:7 Gyr between the instantaneous production of ionizing photons and the later production of metal absorption features (added to the delay due to stellar lifetimes) can provide the full explanation for both puzzles. We calculate the delay in metal production due to finite stellar lifetimes alone and find that it is too short (� 0:2 Gyr) to explain the rapid evolution. The additional delay could naturally be explained as the result of � 100 km=s outflows carrying carbon to distances of � 50–70 kpc, the typical distance between galaxies and Civ absorbers in