A5043368585- Molecular Junctions and Nanostructures
- Organic Electronics and Photovoltaics
- Galaxies: Formation, Evolution, Phenomena
- Luminescence and Fluorescent Materials
- Spectroscopy and Quantum Chemical Studies
- Astronomy and Astrophysical Research
- Conducting polymers and applications
- Mechanical and Optical Resonators
- Force Microscopy Techniques and Applications
- Photonic Crystals and Applications
- Astrophysics and Cosmic Phenomena
- Photoreceptor and optogenetics research
- Photonic and Optical Devices
- Nanofabrication and Lithography Techniques
- Molecular spectroscopy and chirality
- Surface and Thin Film Phenomena
- Porphyrin and Phthalocyanine Chemistry
- Liquid Crystal Research Advancements
- Surface Chemistry and Catalysis
- Laser Material Processing Techniques
- Nonlinear Optical Materials Studies
- Neuroscience and Neural Engineering
- Adaptive optics and wavefront sensing
- Surface Roughness and Optical Measurements
- X-ray Diffraction in Crystallography
Max Planck Institute for Extraterrestrial Physics
2023-2024
University of Southern Denmark
2014-2024
Philipps University of Marburg
1976-2021
Faculty of Design
1998-2018
Carl von Ossietzky Universität Oldenburg
2007-2009
University of Bonn
2009
Humboldt-Universität zu Berlin
2002-2008
University College South Denmark
2007
Humboldt State University
2002-2006
Odense University Hospital
2001-2003
The eROSITA telescope array aboard the Spektrum Roentgen Gamma (SRG) satellite began surveying sky in December 2019, with aim of producing all-sky X-ray source lists and maps an unprecedented depth. Here we present catalogues both point-like extended sources using data acquired first six months survey operations (eRASS1; completed June 2020) over half whose proprietary rights lie German Consortium. We describe observation process, analysis pipelines, characteristics sources. With nearly 930...
Clusters of galaxies can be used as powerful probes to study astrophysical processes on large scales, test theories the growth structure, and constrain cosmological models. The driving science goal SRG/eROSITA All-Sky Survey is assemble a sample X-ray clusters with well-defined selection function determine evolution mass and, hence, parameters. We present here catalog 12 247 optically confirmed galaxy groups detected in 0.2–2.3 keV extended sources 13 116 deg 2 region western Galactic half...
The evolution of the cluster mass function traces growth linear density perturbations, providing valuable insights into structures, nature dark matter, and cosmological parameters governing Universe. primary science goal eROSITA, on board Spectrum Roentgen Gamma (SRG) mission, is to constrain cosmology through function. In this paper, we present a set constraints obtained from 5259 clusters galaxies detected over an area 12791 deg 2 in western Galactic hemisphere eROSITA’s first All-Sky...
Abstract A facile route to soft matter self‐powered bulk heterojunction photodiode detectors sensitive the circular polarization state of light is shown based on intrinsic excitonic dichroism photoactive layer blend. As detecting materials, enantiopure semiconducting small molecular squaraine derivates opposite handedness are employed. Via Mueller matrix ellipsometry, proven be H‐type nature and not originating from mesoscopic structural ordering. Within green spectral range, photodiodes...
Molecular chirality and the inherently connected differential absorption of circular polarized light (CD) combined with semiconducting properties offers great potential for chiral opto-electronics. Here we discuss temperature-controlled assembly enantiopure prolinol functionalized squaraines opposite handedness into intrinsically dichroic, molecular J-aggregates in spincasted thin films. By Mueller matrix spectroscopy accurately probe an extraordinary high excitonic dichroism, which is not...
The first SRG/eROSITA All-Sky Survey (eRASS1) provides the largest intracluster medium-selected galaxy cluster and group catalog covering western Galactic hemisphere. Compared to samples selected purely on X-ray extent, sample purity can be enhanced by identifying candidates using optical near-infrared data from DESI Legacy Imaging Surveys. Using red-sequence-based finder eROMaPPer , we measured individual photometric properties (redshift z λ richness center, BCG position) for 12000 eRASS1...
Number counts of galaxy clusters across redshift are a powerful cosmological probe, if precise and accurate reconstruction the underlying mass distribution is performed -- challenge called calibration. With advent wide deep photometric surveys, weak gravitational lensing by has become method choice to perform this measurement. We measure validate (WL) signature in shape galaxies observed first 3 years DES Y3 caused selected all-sky survey SRG/eROSITA. These data then used determine scaling...
Aims. Characterising galaxy cluster populations from a catalogue of sources selected in astronomical surveys requires knowledge sample incompleteness, known as the selection function. The first All-Sky Survey (eRASS1) by eROSITA on board Spectrum Roentgen Gamma (SRG) has enabled collection large samples clusters detected soft X-ray band over western Galactic hemisphere. driving goal consists constraining cosmological parameters, which puts stringent requirements accuracy and flexibility...
We show by a combination of spectrally resolved fluorescence and atomic force microscopy that individual, single crystalline, needlelike aggregates hexaphenyl molecules with submicron cross-sectional dimensions act as optical waveguides (``nanofibers'') in the blue spectral range. The nanofibers are formed via laser-supported, dipole-assisted self-assembly on crystalline mica substrates. This method allows us to modify morphology individual well their mutual distances overall orientation...
We report on dipole-assisted, self-assembled formation of p-6P and p-5P needles cleaved heated mica (0001) surfaces. Low-energy electron diffraction (LEED) reveals that the are single crystalline with (11̄1̄) face parallel to surface, consisting stacks laying molecules oriented along direction microscopic dipoles surface. They have submicrometer cross-sectional dimensions lengths as large millimeters. Moreover, due strong dipole confinement individual molecules, form domains entities. A...
We study gain and lasing processes in individual self-assembled organic nanofibers grown on mica substrates. The gain-induced response of the is found to depend sensitively fiber structure. In homogeneous fibers where no coherent optical feedback present, high net (of up 103cm−1) results spectral narrowing at material peaks. case strong feedback, which occurs long with randomly distributed scattering centers, turn responsible for low-threshold random laser action.
Abstract A new route to bottom‐up organic nanotechnology is presented. Molecular building blocks with specific optoelectronic properties are designed and grown via directed self‐assembly arrays of morphologically controlled light‐emitting nanofibers on template surfaces. The fibers can be easily transferred from the growth substrate device platforms either as single entities or ordered arrays. Due extraordinary flexibility in design their they serve key elements next‐generation nanophotonic devices.
Superclusters of galaxies mark the large-scale overdense regions in Universe. provide an ideal environment to study structure formation and search for emission intergalactic medium such as cosmic filaments WHIM. In this work, we present largest-to-date catalog X-ray-selected superclusters identified first SRG/eROSITA All-Sky Survey (eRASS1). By applying Friends-of-Friends (FoF) method on galaxy clusters detected eRASS1, 1338 supercluster systems western Galactic hemisphere up redshift 0.8,...
This article presents a parametrized response model that enhances the limit of detection (LOD) piezoelectrically driven microcantilever (PD-MC) based gas sensors by accounting for adsorption-induced variations in elastic properties functionalization layer (binder) and nonlinear motional dynamics PD-MC. The developed is demonstrated quantifying cadaverine, volatile biogenic diamine whose concentration used to assess freshness meat. At low concentrations an increase resonance frequency...
Galaxy cluster gas temperatures ( T ) play a crucial role in many cosmological and astrophysical studies. However, it has been shown that measurements can significantly vary between different X-ray telescopes. These biases propagate to several applications which be used, such as measuring hydrostatic masses constraining the angular variation of parameters. Thus, is important accurately cross-calibrate instruments account for systematic biases. In this work, we present cross-calibration...
Laser-supported, dipole-assisted self-assembly results in blue-light guiding nanostructures, namely single-crystalline nanofibers of hexaphenyl molecules. The are up to 1 mm long, extremely well-aligned each other and their cross sections can be tuned span the range from nonguiding single optical modes at λ=425.5 nm. An analytical theory for such organic waveguides reproduce quantitatively experimentally observed behavior. From measured damping propagating, vibrationally dressed excitons...
Abstract Light‐emitting organic nanofibers made of phenyl molecules like para ‐hexaphenyl ( p ‐6P) and grown on muscovite mica form a model system well‐suited for the study optics in sub‐wavelength regime. We demonstrate that p‐ 6P can be with high control morphology individual nanoaggregates also mutual alignment aggregates by use appropriate growth conditions substrate surfaces. The detached from substrate, thus allowing one to optical response under huge variety fundamentally different...
The detection of the extended X-ray-emission intracluster medium by first SRG/eROSITA All-Sky Survey (eRASS1), combined with optical and near-infrared follow-up, resulted in identification more than 12000 galaxy clusters, yielding precise constraints on cosmological parameters. However, some clusters galaxies can be misclassified as point sources eROSITA's source algorithm due to interplay between point-spread function, shallow depth survey, compact (cool core) X-ray emission, bright active...
The first SRG/eROSITA all-sky X-ray survey, eRASS1, resulted in a catalogue of over twelve thousand optically-confirmed galaxy groups and clusters the western Galactic hemisphere. Using eROSITA images these objects, we measure study their morphological properties, including concentration, central density slope, ellipticity, power ratios, photon asymmetry, centroid shift Gini coefficient. We also introduce new forward-modelled parameters which take account instrument point spread function...
Ultra-light axions are hypothetical scalar particles that influence the evolution of large-scale structures Universe. Depending on their mass, they can potentially be part dark matter component Universe, as candidates commonly referred to fuzzy matter. While strong constraints have been established for pure models, more general scenario where ultra-light constitute only a fraction has limited few observational probes. In this work, we use galaxy cluster number counts obtained from first...
The first SRG/eROSITA all-sky X-ray survey, eRASS1, resulted in a catalogue of over 12000 optically confirmed galaxy groups and clusters the western Galactic hemisphere. Using eROSITA images these objects, we measured studied their morphological properties, including concentration, central density slope, ellipticity, power ratios, photon asymmetry, centroid shift, Gini coefficient. We also introduced new forward-modelled parameters that take account instrument point spread function (PSF),...
We aim to participate in the calibration of X-ray photon count rate halo mass scaling relation galaxy clusters selected first eROSITA All-Sky Survey on western Galactic hemisphere (eRASS1) using weak-lensing (WL) data from fourth release Kilo-Degree (KiDS-1000) . therefore measured radial shear profiles around eRASS1 background galaxies KiDS-1000 as well cluster member contamination. Furthermore, we provide consistency checks with other stage-III surveys that take part Dark Energy Year 3...
Recent advancements in methods used wide-area surveys have demonstrated the reliability of number density galaxy clusters as a viable tool for precision cosmology. Beyond testing current cosmological paradigm, cluster counts can also be to investigate discrepancies currently affecting measurements. In particular, studies based on cosmic shear and other large-scale structure probes routinely find value amplitude fluctuations universe Sh = σ_ (Ω_ m smaller than one inferred from primary...
One-dimensional light amplification in individual p-sexiphenyl nanofibers is investigated. The influence of fiber morphology on propagation properties studied via optical and atomic force microscopy. Isolated are shown to yield low-threshold random laser emission the deep blue. Model calculations coherent one-dimensional media qualitatively reproduce experimental results. Implications for photonic nanosensors briefly discussed.
As a step toward the realization of neuroprosthetics for vision restoration, we follow an electrophysiological patch-clamp approach to study fundamental photoelectrical stimulation mechanism neuronal model cells by organic semiconductor-electrolyte interface. Our photoactive layer consisting anilino-squaraine donor blended with fullerene acceptor is supporting growth cell line (N2A cells) without adhesion on it and not impairing viability. The transient photocurrent signal upon illumination...