We present initial results from a Ðeld survey for extremely red objects [EROs, deÐned here as (R[K@) º 6 mag] covering 154 arcmin2 of sky, from the Ðrst of seven deep, wide-Ðeld K@ images obtained as part of the Calar Alto Deep Imaging Survey (CADIS). The 5 p point source detection limits are K@ \ 20.5 mag and R \ 25.0 mag, while extended-source limits are up to 0.50È0.75 mag brighter. We identify a total of eight bright EROs with K@ ¹ 19.0 mag. Six of these bright EROs are resolved and are likely to be galaxies, while the remaining two are unresolved, with colors consistent with their being low-mass galactic stars. We derive a surface density for the six bright, extragalactic EROs of 0.039^0.016 arcmin~2, which is higher by a factor of 4 than previous values. We estimate that the volume density of bright EROs to be as high as that of nearby Seyfert galaxies.

Abstract. The emission line survey within the Calar Alto Deep Imaging Survey (CADIS) detects emission line galaxies by a scan with an imaging Fabry-Perot interferometer. It covers 5 fields of >100 each in three wavelengths windows centered on λ 700, 820, and 920 nm, and reaches to a typical limiting line flux of 3× 10 −20 W m −2 . This is the deepest emission line survey covering a field of several 100 . Galaxies between z = 0.25 and z = 1.4 are detected by prominent emission lines (from Hα to [O ]372.7) falling into the FP scans. Additional observations with a dozen medium band filters allow to establish the line identification and thus the redshift of the galaxies to better than σ z = 0.001. On the basis of a total of more than 400 emission line galaxies detected in Hα (92 galaxies), [O ]500.7 (124 galaxies), or [O ]372.7 (222 galaxies) we measure the instantaneous star formation rate (SFR) in the range 0.24 < z < 1.21. With this purely emission line selected sample we are able to reach much fainter emission line galaxies than previous, continuum-selected samples. Thus completeness corrections are much less important. Although the relative [O ] emission line strength depends on excitation and metallicity and shows strong variation, the mean line ratios yield SFR[O ] values consistent with the SFR evolution. Our results substantiates the indications from previous studies (based on small galaxy samples) that the SFR decreases by a factor of ∼20 between z = 1.2 and today. In fact, for a Ω m = 0.3, Ω λ = 0.7 cosmology, we find an exponential declineρ SFR ∝ exp(−t lookback /2.6 Gyr). This decrease of the SFR with time follows an exponential law which is compatible with the decreasing galaxy merger rate as expected from model calculations. The inferred SF density is in perfect agreement with that deduced from the FIR emission of optically selected galaxies which is explained by a large overlap between both populations. We show that self-consistent extinction corrections of both our emission lines and the UV continua lead to consistent results for the SF density.

Abstract. Flood detention areas serve the primary purpose of controlled water storage during large flood events in order to decrease the flood risk downstream along the river. These areas are often used for agricultural production. While various damage estimation methods exist for urban areas, there are only a few, most often simpler approaches for loss estimation in rural areas. The loss assessment can provide an estimate of the financial provisions required for the farmers' compensation (e.g., in the context of cost-benefit analyses of detention measures). Flood risk is a combination of potential damage and probability of flooding. Losses in agricultural areas exhibit a strong seasonal pattern, and the flooding probability also has a seasonal variation. In the present study, flood risk is assessed for a planned detention area alongside the Elbe River in Germany based on two loss and probability estimation approaches of different time frames, namely a monthly and an annual approach. The results show that the overall potential damage in the proposed detention area amounts to approximately 40 000 € a−1, with approximately equal losses for each of the main land uses, agriculture and road infrastructure. A sensitivity analysis showed that the probability of flooding (i.e., the frequency of operation of the detention area) has the largest impact on the overall flood risk.

Abstract. We present the B-band luminosity function and comoving space and luminosity densities for a sample of 2779 I-band selected field galaxies based on multi-color data from the CADIS survey. The sample is complete down to I815 = 22 without correction and with completeness correction extends to I815 = 23.0. By means of a new multi-color analysis the objects are classified according to their spectral energy distributions (SEDs) and their redshifts are determined with typical errors of δz ≤ 0.03. We have split our sample into four redshift bins between z = 0.1 and z = 1.04 and into three SED bins E-Sa, Sa-Sc and starbursting (emission line) galaxies. The evolution of the luminosity function is clearly differential with SED. The normalization φ * of the luminosity function for the E-Sa galaxies decreases towards higher redshift, and we find evidence that the comoving galaxy space density decreases with redshift as well. In contrast, we find φ * and the comoving space density increasing with redshift for the Sa-Sc galaxies. For the starburst galaxies we find a steepening of the luminosity function at the faint end and their comoving space density increases with redshift.

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