The VISTA near infrared survey of the Magellanic System (VMC) will provide deep Y JKs photometry reaching stars in the oldest turn-off point all over 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 first...

Aims. The knowledge of the number and physical nature of low-metallicity massive galaxies is crucial for determining and interpreting the mass-metallicity relation (MZR). Methods. Using VLT-ISAAC near-infrared (NIR) spectroscopy of 39 zCOSMOS 0.5 < z < 0.9 galaxies, we have measured Hα and [N II] λ 6584 emission line fluxes for galaxies with [O II] λ 3727, Hβ, and [O III] λ 5007 available from ...

Based on the gamma-ray burst (GRB) event rate at redshifts of 4 ≤ z ≤ 12, which is assessed by the spectral peak energy-to-luminosity relation recently found by Yonetoku et al., we observationally derive the star formation rate (SFR) for Pop III stars in a high redshift universe. As a result, we find that Pop III stars could form continuously at 4 ≤ z ≤ 12. Using the derived Pop III SFR, we att...

Abstract. The recent finding that the IGIMF (integrated galaxial initial stellar mass function) composed of all newly formed stars in all young star clusters has, in dependence of the SFR, a steeper slope in the high mass regime than the underlying canonical IMF of each star cluster offers new insights into the galactic star formation process: The classical linear relation between the SFR and t...

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Using self-consistent chemodynamical simulations including star formation, supernova feedback, and chemical enrichment, I show the dependence of cosmic star formation and chemical enrichment histories on the initial mass function (IMF). The effects of Pop-III IMF can be only seen in the elemental abundance ratios at z > ∼ 4 or [Fe/H] < ∼ −2. The preferable IMF has a flatter slope in the case of...

Abstract Using a currently most representative sample of 477 late-type galaxies within 11 Mpc the Milky Way with measured star-formation rates (SFRs) from far ultraviolet (FUV) and Hα emission line fluxes, we select extreme ratios: SFR(Hα)/SFR(FUV) &amp;gt; 2 &amp;lt; 1/20. Each subsample amounts to ∼5% total number consists dwarf stellar masses M*/M⊙ = (5.5 − 9.5) dex. In spite huge difference...

Most color imaging systems today are based on a monochrome detector with a color filter array (CFA). Typically the Bayer CFA is used. An imaging system’s spatial frequency response (SFR) is one of its most meaningful characteristics. It is directly related to the system’s capability to resolve objects. This work presents a model for calculating the SFR of a Bayer color capture system. Our two d...

Conventional point spread function (PSF) measurement methods often use parametric models for the estimation of the PSF. This limits the shape of the PSF to a specific form provided by the model. However, there are unconventional imaging systems like multispectral cameras with optical bandpass filters, which produce an ab-normal, e.g., unsymmetric PSF. To estimate such PSFs we have developed a n...

Methods for the determination of star formation rates (SFR) from integrated populations are reviewed. We discuss the assumptions and underlying uncertainties (e.g. IMF slope, Mup, metallicity, SF history etc.) used in the calibrations of UV, FIR, Hα, and [O ii] λ3727 indicators. The “universality” of empirically calibrated indicators such as [O ii] is examined. We also present preliminary resul...