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ESA's PLATO mission aims the detection and characterization of terrestrial planets around solar-type stars as well as the study of host star properties. The noise-to-signal ratio (NSR) is the main performance parameter of the PLATO instrument, which consists of 24 Normal Cameras and 2 Fast Cameras. In order to justify, verify and breakdown NSR-relevant requirements the software simulator PINE was developed. PINE models the signal pathway from a target star to the digital output of a camera based on physical models and considers the major noise contributors. In this paper, the simulator's coarse mode is introduced which allows fast performance analyses on instrument level. The added value of PINE is illustrated by exemplary applications. [ABSTRACT FROM AUTHOR]

There is a great need for an easy-to-use tool to simulate drying of concrete floors. In order to model practical situations, the tool should take into account changing conditions, especially wetting at worksite, but also temperature. For this purpose, a simulation program was developed for drying time estimations for concrete floors, which was published in 2021 and is named as the "by2020 Concrete drying time estimate". This study presents the results of the laboratory test series conducted to calibrate the drying time estimations of the by2020 software. As all possible scenarios for practical situations were not possible to study in the test series, results from the literature were partly used for calibration and validation of the tool. A methodology for test series for calibration of the drying time estimation model is proposed based on this study. It was found that a model suitable for practical applications can be implemented based on relative humidity measurements only. However, the tests series of relative humidity measurements should take into account the influence of various factors such as wetting period and different temperature conditions. [ABSTRACT FROM AUTHOR]

The Paleoproterozoic Svecofennian Central Finland Granitoid Complex (CFGC) has been regarded as an area of low mineralisation potential. The Hiekkapohja area, 20 km north-east of the town of Jyväskylä, host a concentration of variable metalliferous showings. Samples from mineralised boulders and outcrops display variable combinations of anomalously high concentrations of Cu, Mo, Zn, Pb, W, Pb, Ag, As, and Au. The area is composed mainly of peraluminous and ferroan granitoids. The dominant porphyritic Hiekkapohja granodiorite (~1.88 Ga) is cross-cut by the equigranular Soimavuori granite of similar age. The porphyritic Lehesvuori granite on the western side of the study area represents marginally older (~1.89 Ga) magmatism. The paragenetic sequence of the ore minerals shows that the Hiekkapohja area has been affected by at least two separate stages of hydrothermal activity. The first mineralisation stage was widespread, crystallising typically chalcopyrite, pyrrhotite, sphalerite, galena, arsenopyrite, magnetite and Ag-bearing minerals. After the first stage, a low temperature oxidising phase formed hematite and marcasite. The second mineralisation stage enclosed low temperature minerals, such as marcasite and native Ag and Ag-minerals, as inclusions inside chalcopyrite, pyrite, pyrrhotite, sphalerite, and arsenopyrite. The mineralised samples typically display signs of K-metasomatism and less commonly signs of propylitic alteration. During the second mineralisation stage the fluid flow was controlled by the dominant 120°-135° trending shear zones. Both the hydrothermal activity and the regional geology indicate that porphyry type ore forming processes have occurred in the Hiekkapohja area. Paleoproterozoic resetting of the remanent magnetisation is further evidence for the role of the hydrothermal system. [ABSTRACT FROM AUTHOR]

One of the most powerful techniques to study the dark sector of the Universe is weak gravitational lensing. In practice, to infer the reduced shear, weak lensing measures galaxy shapes, which are the consequence of both the intrinsic ellipticity of the sources and of the integrated gravitational lensing effect along the line of sight. Hence, a very large number of galaxies is required in order to average over their individual properties and to isolate the weak lensing cosmic shear signal. If this 'shape noise' can be reduced, significant advances in the power of a weak lensing surveys can be expected. This paper describes a general method for extracting the probability distributions of parameters from catalogues of data using Voronoi cells, which has several applications, and has synergies with Bayesian hierarchical modelling approaches. This allows us to construct a probability distribution for the variance of the intrinsic ellipticity as a function of galaxy property using only photometric data, allowing a reduction of shape noise. As a proof of concept the method is applied to the CFHTLenS survey data. We use this approach to investigate trends of galaxy properties in the data and apply this to the case of weak lensing power spectra. [ABSTRACT FROM AUTHOR]

Radiation damage to space-based charge-coupled device detectors creates defects which result in an increasing charge transfer inefficiency (CTI) that causes spurious image trailing. Most of the trailing can be corrected during post-processing, by modelling the charge trapping and moving electrons back to where they belong. However, such correction is not perfect - and damage is continuing to accumulate in orbit. To aid future development, we quantify the limitations of current approaches, and determine where imperfect knowledge of model parameters most degrades measurements of photometry and morphology. As a concrete application, we simulate 1.5 x 109 'worst-case' galaxy and 1.5 x 108 star images to test the performance of the Euclid visual instrument detectors. There are two separable challenges. If the model used to correct CTI is perfectly the same as that used to add CTI, 99.68 per cent of spurious ellipticity is corrected in our setup. This is because readout noise is not subject to CTI, but gets overcorrected during correction. Secondly, if we assume the first issue to be solved, knowledge of the charge trap density within Δp/p = (0.0272 ± 0.0005) per cent and the characteristic release time of the dominant species to be known within ΔT/T = (0.0400 ± 0.0004) per cent will be required. This work presents the next level of definition of in-orbit CTI calibration procedures for Euclid. [ABSTRACT FROM AUTHOR]

Radiation damage to space-based charge-coupled device detectors creates defects which result in an increasing charge transfer inefficiency (CTI) that causes spurious image trailing. Most of the trailing can be corrected during post-processing, by modelling the charge trapping and moving electrons back to where they belong. However, such correction is not perfect - and damage is continuing to accumulate in orbit. To aid future development, we quantify the limitations of current approaches, and determine where imperfect knowledge of model parameters most degrades measurements of photometry and morphology. As a concrete application, we simulate 1.5 × 109 'worst-case' galaxy and 1.5 × 108 star images to test the performance of the Euclid visual instrument detectors. There are two separable challenges. If the model used to correct CTI is perfectly the same as that used to add CTI, 99.68 per cent of spurious ellipticity is corrected in our setup. This is because readout noise is not subject to CTI, but gets overcorrected during correction. Secondly, if we assume the first issue to be solved, knowledge of the charge trap density within Δp/p = (0.0272 ± 0.0005) per cent and the characteristic release time of the dominant species to be known within Δt/t = (0.0400 ± 0.0004) per cent will be required. This work presents the next level of definition of in-orbit CTI calibration procedures for Euclid. [ABSTRACT FROM AUTHOR]

In this paper we present the testing of a back-illuminated development Euclid Visible Instrument (VIS) Charge-Coupled Device (CCD) to measure the intrinsic CCD Point Spread Function (PSF) characteristics using a novel modelling technique. We model the optical spot projection system and the CCD273-84 PSF jointly. We fit a model using Bayesian posterior probability density function, sampling to all available data simultaneously. The generative model fitting is shown, using simulated data, to allow good parameter estimations even when these data are not well sampled. Using available spot data we characterise a CCD273-84 PSF as a function of wavelength and intensity. The CCD PSF kernel size was found to increase with increasing intensity and decreasing wavelength. [ABSTRACT FROM AUTHOR]

ABSTRACT We make use of a semi-analytic cosmological model that includes simple prescriptions for dust attenuation and emission to make predictions for the observable and physical properties of galaxies that may be detected by the recently launched Herschel Space Observatory in deep fields such as Great Observatories Origins Deep Survey- Herschel. We compare our predictions for differential galaxy number counts in the Herschel Photodetector Array Camera and Spectrometer (PACS) (100 and 160 μm) and Spectral and Photometric Imaging Receiver (SPIRE) (250, 350 and 500 μm) bands with available observations. We find very good agreement with the counts in the PACS bands, for the overall counts and for galaxies binned by redshift at z < 2. At z > 2 our model underpredicts the number of bright galaxies in the PACS bands by a factor of 10. The agreement is much worse for all three SPIRE bands and becomes progressively worse with increasing wavelength. We discuss a number of possible reasons for these discrepancies and hypothesize that the effect of blending on the observational flux estimates is likely to be the dominant issue. We note that the PACS number counts are relatively robust to changes in the dust-emission templates, at least for the three sets of templates that we have tested, while the predicted SPIRE number counts are more template dependent especially at low redshift. We present quantitative predictions for the relationship between the observed PACS 160 and SPIRE 250 μm fluxes and physical quantities such as halo mass, stellar mass, cold gas mass, star formation rate and total infrared (IR) luminosity, at different redshifts. We also present predictions for the radial sizes of Herschel-selected discs at high redshift ( z > 2) and find reasonable agreement with the available observations. Finally, we present quantitative predictions for the correlation between the PACS 160 μm flux and the probability that a galaxy has experienced a recent major or minor merger. Although our models predict a strong correlation between these quantities, such that more IR-luminous galaxies are more likely to be merger driven, we find that a significant fraction (more than half) of all high-redshift IR-luminous galaxies detected by Herschel are able to attain their high star formation rates without enhancement by a merger. [ABSTRACT FROM AUTHOR]

We study the properties, evolution and formation mechanisms of isolated field elliptical (IfE) galaxies. We create a ‘mock’ catalogue of IfE galaxies from the Millennium Simulation Galaxy Catalogue, and trace their merging histories. The formation, identity and assembly redshifts of simulated isolated and non-isolated elliptical galaxies are studied and compared. Observational and numerical data are used to compare age, mass and the colour–magnitude relation. Our results, based on simulation data, show that almost 7 per cent of all elliptical galaxies brighter than −19 mag in B band can be classified as IfE galaxies. Results also show that isolated elliptical galaxies have a rather flat luminosity function; a number density of mag−1, throughout their B-band magnitudes. IfE galaxies show bluer colours than non-isolated elliptical galaxies and they appear younger, in a statistical sense, according to their mass-weighted age. IfE galaxies also form and assemble at lower redshifts compared to non-isolated elliptical galaxies. About 46 per cent of IfE galaxies have undergone at least one major merging event in their formation history, while the same fraction is only ∼33 per cent for non-isolated ellipticals. Almost all (∼98 per cent) isolated elliptical galaxies show merging activity during their evolution, pointing towards the importance of mergers in the formation of IfE galaxies. The mean time of the last major merging is at or 6 Gyr ago for isolated ellipticals, while non-isolated ellipticals experience their last major merging significantly earlier at or 8 Gyr ago. After inspecting merger trees of simulated IfE galaxies, we conclude that three different, yet typical, formation mechanisms can be identified: solitude, coupling and cannibalism. Our results also predict a previously unobserved population of blue, dim and light galaxies that fulfil observational criteria to be classified as IfE galaxies. This separate population comprises ∼26 per cent of all IfEs. [ABSTRACT FROM AUTHOR]

Intranight polarization variability in active galactic nuclei (AGN) has not been studied extensively so far. Studying the variability in polarization makes it possible to distinguish between different emission mechanisms. Thus, it can help answering the question if intranight variability in radio-loud and radio-quiet AGN is of the same or of fundamentally different origin. In this paper, we investigate intranight polarization variability in AGN. Our sample consists of 28 AGN at low to moderate redshifts , 12 of which are radio-quiet quasars (RQQs) and 16 are radio-loud blazars. The subsample of blazars consists of eight flat-spectrum radio-quasars (FSRQs) and eight BL Lac objects. Each AGN was observed for a time-span of ∼4 h in the R band to measure polarization and variability. Using statistical methods, we determine duty cycles for polarized emission and polarization intranight variability. We find clear differences between the two samples. A majority of the radio-loud AGN show moderate to high degrees of polarization, more than half of them also show variability in polarization. There seems to be a dividing line for polarization intranight variability at per cent over which all objects vary in polarization. We did not find clear correlations between the strength of the variability and the redshift or degree of polarization. Only two out of 12 RQQs show polarized emission, both at levels of per cent. The lack of polarization intranight variability in radio-quiet AGN points towards accretion instabilities being the cause for intranight flux variability whereas the high duty cycle of polarization variability in radio-loud objects is more likely caused by instabilities in the jet or changes of physical conditions in the jet plasma. We were able to constrain the time-scale of the detected variations to >4 h. Further studies of intranight polarization variability will be necessary to reveal exact physical conditions behind this phenomenon. [ABSTRACT FROM AUTHOR]

We have compared numerical simulations to observations for the nearby (<40 Mpc) groups of galaxies. The group identification is carried out using a group-finding algorithm developed by Huchra & Geller. Using cosmological N-body simulation code with the Λcold dark matter (ΛCDM) cosmology, we show that the dynamical properties of groups of galaxies identified from the simulation data are, in general, in a moderate, within 2σ, agreement with the observational catalogues of groups of galaxies. As simulations offer more dynamical information than observations, we used the N-body simulation data to calculate whether the nearby groups of galaxies are gravitationally bound objects by using their virial ratio. We show that in a ΛCDM cosmology about 20 per cent of nearby groups of galaxies, identified by the same algorithm as in the case of observations, are not bound, but merely groups in a visual sense. This is quite significant, specifically because estimations of group masses in observations are often based on an assumption that groups of galaxies found by the friends-of-friends algorithm are gravitationally bound objects. Simulations with different resolutions show the same results. We also show how the fraction of gravitationally unbound groups varies when the apparent magnitude limit of the sample and the value of the cosmological constant Λ is changed. In general, a larger value of the generates slightly more unbound groups. [ABSTRACT FROM AUTHOR]