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Stephane Charlot

Publications and source records attributed to Stephane Charlot.

183 records · Page 11Linked to original sources
arXiv1996

Angular Sizes of Faint Field Disk Galaxies: Intrinsic Luminosity Evolution

In order to explain the small scale-lengths detected in the recent deep field observations performed from large ground-based telescopes and from the Hubble Space Telescope, we investigate the predictions at high redshifts for disk galaxies that formed by infall. Changes with redshift in the observed properties of field galaxies are directly related to the evolution of the disks and of the stellar populations. We see that changes in the rest frame luminosity of a galaxy induce smaller values of half-light radii than are predicted assuming no evolution. Comparisons are presented with two observed samples from Mutz et al. (1994) and Smail et al. (1995).

astro-ph↗
arXiv1996

Cosmic Emissivity and Background Intensity from Damped Lyman-Alpha Galaxies

We present a new method to compute the cosmic emissivity $\E_ν$ and background intensity $J_ν$. Our method is based entirely on data from quasar absorption-line studies, namely, the comoving density of HI and the mean metallicity and dust-to-gas ratio in damped Ly$α$ galaxies. These observations, when combined with models of cosmic chemical evolution, are sufficient to determine the comoving rate of star formation as a function of redshift. From this, we compute $\E_ν$ and $J_ν$ using stellar population synthesis models. Our method includes a self-consistent treatment of the absorption and reradiation of starlight by dust. In all of our calculations, the near-UV emissivity declines rapidly between $z\approx1$ and $z=0$, in agreement with estimates from the Canada-France Redshift Survey. The background intensity is consistent with a wide variety of observational limits and with a tentative detection at far-IR wavelengths.

astro-ph↗