Keck Mid-Infrared Imaging of the QSO 2237+0305

Using the Long Wavelength Spectrometer on Keck I, we have imaged the gravitationally lensed radio quiet quasi-stellar object (QSO) 2237+0305 at 8.9 and 11.7 microns for the first time. The mid-infrared flux ratios are inconsistent with the optical flux ratios, but agree with the radio flux ratios and with some published gravitational lens models. These flux ratios indicate that the infrared emission is not affected by microlensing, which rules out the synchrotron emission model. The infrared emission is likely produced by hot dust extended on a length scale of more than 0.03 parsecs. The spectral energy distribution further implies a narrow range of dust temperatures, suggesting that the dust may be located in a shell extending between ~1 to 3 parsecs from the nucleus, and intercepting about half of the QSO luminosity.Comment: Accepted to ApJ, 8 pages, 3 figures (1 color). Please email [email protected] if you have any comments or questions about this pape

Bochner-Almost Periodicity for Stochastic Processes

International audienceWe compare several notions of almost periodicity for continuous processes defined on the time interval $I=R$ or $I=[0,+\infty)$ with values in a separable Banach space $E$ (or more generally a separable completely regular topological space): almost periodicity in distribution, in probability, in quadratic mean, almost sure almost periodicity, almost sure equi-almost periodicity. In the deterministic case, all these notions reduce to Bochner-almost periodicity, which is equivalent to Bohr-almost periodicity when $I=R$, and to asymptotic Bohr-almost periodicity when $I=[0,+\infty)$

San Bernardino Cave (Italy) and the appearance of Levallois technology in Europe: results of a radiometric and technological reassessment.

The introduction of Levallois technology in Europe marked the transition from the Lower to the early Middle Paleolithic. This new method of flake production was accompanied by significant behavioral changes in hominin populations. The emergence of this technological advance is considered homogeneous in the European archaeological record at the Marine isotopic stage (MIS) 9/MIS 8 boundary. In this paper we report a series of combined electron spin resonance/U-series dates on mammal bones and teeth recovered from the lower units of San Bernardino Cave, Italy, and the technological analyses of the lithic assemblages. San Bernardino Cave has yielded the earliest evidence of Levallois production on the Italian Peninsula recovered to date. In addition to our results and the review of the archaeological record, we describe the chronological and geographical differences between European territories and diversities in terms of technological developments. The belated emergence of Levallois technology in Italy compared to western Europe corresponds to the late Italian Neanderthal speciation event. The new radiometric dates and the technological analyses of San Bernardino Cave raise the issue of the different roles of glacial refugia in the peopling and the spread of innovative flaking strategies in Europe during the late Middle Pleistocene