Star formation is inefficient. Only a few percent of the available gas in molecular clouds forms stars, leading to the observed low star formation rate (SFR). The same holds when averaged over many molecular clouds, such that the SFR of whole galaxies is again surprisingly low. Indeed, considering the low temperatures, molecular clouds should be highly gravitationally unstable and collapse on t...

It has been suggested that a continuous low star formation rate has been the dominant regime in IZw 18 and in dwarf galaxies for the lifetime of these objects (Legrand et al. 1999). Here, we discuss and model various star-forming histories for IZw 18. Particularly, we show that if the metallicity observed in IZw 18 results from starburst events only, the observed colors constrain the fraction o...

BACKGROUND The Swedish Fracture Register (SFR) currently contains information on more than 190,000 fractures. Patient Reported Outcome Measures (PROMs) are used for monitoring functional results after fracture treatment. One weakness, as in many surveys, is a low response rate. The aim of the current study was to examine if non-responders of a survey in the SFR differ in PROMs scores, how age a...

At a redshift of 0.18, Abell 1689 is so far the most distant cluster of galaxies for which substantial mid–infrared (MIR) data have been published. Its mapping with the ISOCAM camera onboard the ISO satellite allowed the detection of 30 cluster members at 6.75 μm (LW2 filter) and 16 cluster members at 15 μm (LW3 filter) within a clustercentric radius of 0.5 Mpc (?) Paper I]Fadda00b. We present ...

Context. Ultraluminous infrared galaxies are merging systems characterized for containing large amounts of dust and emitting the bulk of their energy in the infrared. Dust affects several of the observed properties derived from optical and near-IR rest-frame data such as the stellar morphology, and the ionized gas distribution. Systematic analysis of the dust distribution in representative samp...

The well-established Modulation Transfer Function (MTF) is an imaging performance parameter that is well suited to describing certain sources of detail loss, such as optical focus and motion blur. As performance standards have developed for digital imaging systems, the MTF concept has been adapted and applied as the spatial frequency response (SFR). The international standard for measuring digi...

The VISTA near infrared survey of the Magellanic System (VMC) will provide deep Y JKs photometry reaching stars in the oldest turn-off point throughout the Magellanic Clouds (MCs). As part of the preparation for the survey, we aim to access the accuracy in the star formation history (SFH) that can be expected from VMC data, in particular for the Large Magellanic Cloud (LMC). To this aim, we fir...

January 2003 is still alive in my memory: a medical student during his IFMSA exchange in Egypt wanders the premises of the University Hospital in As-syut. Instead of the research in neural tube defects in newborns he is supposed to do, he spends his days until dusk in various operation theatres watching surgeries – many of them for the first time in his life – and has no idea about his future c...

We describe a technique that for the first time measures star formation rates (SFRs) in damped Lyman alpha systems (DLAs) directly. We assume that massive stars form in DLAs, and that the FUV radiation they emit heats the gas by the grain photoelectric mechanism. We infer the heating rate by equating it to the cooling rate measured by the strength of CII∗ 1335.7 absorption. Since the heating ra...