The interstellar extinction curve from 4000 Å to 6500 Å

Indicators of star formation : 4000 Å break and Balmer lines

The behaviour of the 4000 Å break index and of the equivalent width of the main Balmer lines is investigated a) for a single star as a function of effective temperature, gravity and metallicity and b) for a single stellar population as a function of age and metallicity. Consequences for the interpretation of integrated spectra are presented.

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Wavelength (å)

We present near-infrared (observed frame) spectra of the high-redshift quasar S4 0636+68 at z = 3.2 which was previously thought to be one of a group of “strong” Fe II emitters (i.e., F (Fe IIλλ4434–4684)/F (Hβ) > 1). Our K-band spectrum clearly shows emission lines of Hβ and [O III]λλ4959, 5007 as well as optical Fe II emission. Our computed value of F (Fe II λλ4434–4684)/F (Hβ) ≃ 0.8 for S4 0...

The Å Publish/Subscribe Framework

This paper describes the design and implementation of a novel decentralized publish/subscribe framework. The primary goal of the design was for a high level of end-developer and user accessibility and simplicity. Furthermore, it was desired to have strong support for occasionally-connected clients and support for mobile and web-based systems. Content-based event patterns can be defined using sc...

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