A5043157830- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Astronomy and Astrophysical Research
- Molecular Spectroscopy and Structure
- Astronomical Observations and Instrumentation
- Astrophysical Phenomena and Observations
- Galaxies: Formation, Evolution, Phenomena
- Adaptive optics and wavefront sensing
- Atmospheric Ozone and Climate
- Solar and Space Plasma Dynamics
- Calibration and Measurement Techniques
- Planetary Science and Exploration
- Space Exploration and Technology
- Transition Metal Oxide Nanomaterials
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- Spacecraft and Cryogenic Technologies
- Radio Astronomy Observations and Technology
- Scientific Research and Discoveries
- Spectroscopy and Laser Applications
- Gas Sensing Nanomaterials and Sensors
- Ga2O3 and related materials
- Astrophysics and Cosmic Phenomena
- Superconducting Materials and Applications
Kiel University
2016-2025
Institute of Theoretical Physics
2009-2024
Max Planck Institute for Astronomy
2012-2022
University of Regensburg
2022
The University of Sydney
2020
Centro de Astrobiología
2018-2020
Universidad Autónoma de Madrid
2020
Technische Universität Berlin
2018-2019
University of Virginia
2010-2018
University of Cambridge
2018
In the following we present material in tabular and graphical form, with aim to allow non-specialist obtain a realistic estimate of diffuse night sky brightness over wide range wavelengths from far UV longward Lyα far-infrared. At same time data are provide reference for cases which background has be discussed, including planning space observations issue protection observatory sites. We try give critical presentation status at beginning 1997.
Recent observations by the Atacama Large Millimeter/submillimeter Array (ALMA) of disks around young stars revealed distinct asymmetries in dust continuum emission. In this work we want to study axisymmetric and non-axisymmetric structures, evocated magneto-rotational instability outer regions protoplanetary disks. We combine results state-of-the-art numerical simulations with post-processing radiative transfer (RT) generate synthetic maps predictions for ALMA. performed non-ideal global 3D...
We report on the properties of pre-main-sequence objects in Taurus molecular clouds as observed seven mid- and far-infrared bands with Spitzer Space Telescope. There are 215 previously identified members star-forming region our ∼44 deg2 map; these exhibit a range colors that we take to define young stars still surrounded by circumstellar dust (noting ∼20% bona fide no detectable excesses). looked for new survey field similar properties, aided extensive optical, X-ray, ultraviolet imaging,...
The AGN-heated dust distribution (the "torus") is increasingly recognized not only as the absorber required in unifying models, but a tracer for reservoir that feeds nuclear Super-Massive Black Hole. Yet, even its most basic structural properties (such extent, geometry and elongation) are unknown all few archetypal objects. Since AGNs unresolved mid-infrared, we utilize MID-infrared interferometric Instrument (MIDI) at Very Large Telescope Interferometer (VLTI) sensitive to structures small...
view Abstract Citations (327) References (55) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Lunar Occultation and Direct Imaging Survey of Multiplicity in the Ophiuchus Taurus Star-forming Regions Simon, M. ; Ghez, A. Leinert, Ch. Cassar, L. Chen, W. P. Howell, R. Jameson, F. Matthews, K. Neugebauer, G. Richichi, We present an IR lunar occultation direct imaging search for companions star-forming region update a similar region. The is sensitive to angular...
Aims.To test the dust torus model for active galactic nuclei directly, we study extent and morphology of nuclear distribution in Circinus galaxy using high resolution interferometric observations mid-infrared.
We present the first long baseline mid-infrared interferometric observations of circumstellar disks surrounding Herbig Ae/Be stars. The were obtained using instrument MIDI at European Southern Observatory (ESO) Very Large Telescope Interferometer VLTI on Cerro Paranal. 102 m given by telescopes UT1 and UT3 was employed, which provides a maximum full spatial resolution 20 milli-arcsec (mas) wavelength 10 μm. signal spectrally dispersed 30, giving resolved visibility information from 8 μm to...
We present Spitzer photometric (IRAC and MIPS) spectroscopic (IRS low resolution) observations for 314 stars in the Formation Evolution of Planetary Systems Legacy program. These data are used to investigate properties evolution circumstellar dust around solar-type spanning ages from approximately 3 Myr–3 Gyr. identify 46 sources that exhibit excess infrared emission above stellar photosphere at 24 μm, 21 with excesses 70 μm. Five an have characteristics optically thick primordial disks,...
Tori of Active Galactic Nuclei are made up a mixture hot and cold gas, as well dust. In order to protect the dust grains from destruction by gas energetic radiation accretion disk, is often assumed be distributed in clouds. our new 3D model AGN tori, torus modelled wedge-shaped disk which dusty clouds randomly distributed, taking density distribution corresponding continuous into account. We especially concentrate on differences between clumpy models terms temperature distributions, surface...
Transitional disks represent a short stage of the evolution circumstellar material. Studies dust grains in these objects can provide pivotal information on mechanisms planet formation. Dissimilarities spatial distribution small (micron-size) and large (millimeter-size) have recently been pointed out. Constraints be obtained by imaging scattered light at near-infrared wavelengths. We aim resolving structures surface layer transitional (with particular emphasis inner 10 - 50 AU), thus...
Aims. We present a panchromatic study, involving multiple technique approach, of the circumstellar disc surrounding T Tauri star IM Lupi (Sz 82). Methods. have undertaken comprehensive observational study using photometry, spectroscopy, millimetre interferometry and multi-wavelength imaging. For first time, is resolved from optical near-infrared wavelengths in scattered light, to regime thermal emission. Our data-set, conjunction with existing photometric data, provides an extensive coverage...
This paper is one in a series presenting results obtained within the Formation and Evolution of Planetary Systems (FEPS) Legacy Science Program on Spitzer Space Telescope. Here we present study dust processing growth seven protoplanetary disks. Our spectra indicate that circumstellar silicate grains have grown to sizes at least 10 times larger than observed interstellar medium show evidence for non-negligible (~5% mass fractions) contribution from crystalline species. These are similar those...
Debris discs are a consequence of the planet formation process and constitute fingerprints planetesimal systems. Their solar system's counterparts asteroid Edgeworth-Kuiper belts. The DUNES survey aims at detecting extra-solar analogues to belt around solar-type stars, putting in this way system into context. allows us address some questions related prevalence properties We used {\it Herschel}/PACS observe sample nearby FGK stars. Data 100 160 $\mu$m were obtained, complemented cases with...
We present H- and Ks-band polarized differential images (PDI) of the Herbig Ae/Be star HD142527, revealing its optically thick outer disk nearly empty gap. The very small inner working angle (~0.1") high resolution achievable with an 8m-class telescope, together a careful polarimetric calibration strategy, allow us to achieve that surpass quality previous scattered light images. Previously known substructures are resolved more clearly new structures seen. Specifically, we able resolve 1)...
We present H-band Very Large Telescope/NACO polarized light images of the Herbig Ae/Be star HD 169142 probing its protoplanetary disk as close ∼01 to star. Our trace face-on out ∼17 (∼250 AU) and reveal distinct substructures for first time: (1) inner (≲20 appears be depleted in scattering dust grains; (2) an unresolved rim is imaged at ∼25 AU; (3) annular gap extends from ∼40 70 (4) local brightness asymmetries are found on opposite sides gap. discuss different explanations observed...
We resolved the enigma of anisotropic electronic transport in strained vanadium dioxide (VO2) films by inquiring into role that strain plays nanoscale phase separation vicinity insulator-to-metal transition. The root source anisotropy was visualized as formation a peculiar unidirectional stripe state which accompanies Furthermore, infrared spectroscopy unveils distinct facets electron-lattice interplay at three different stages These include initial sparse nonpercolating metallic domains...
We present polarimetric differential imaging (PDI) data of the circumstellar disk around Herbig Ae/Be star HD100546 obtained with VLT/NACO. resolve in polarized light H and Ks filter between ~0.1-1.4" (i.e., ~10-140 AU). The innermost regions are directly imaged for first time mean apparent inclination position angle derived. surface brightness along major axis drops off roughly S(r) ~ r^-3 but has a maximum 0.15" suggesting marginal detection main inner rim at ~15 AU. find significant...
Aims: We present POLARIS (POLArized RadIation Simulator), a newly developed three-dimensional Monte-Carlo radiative transfer code. was designed to calculate dust temperature, polarization maps, and spectral energy distributions. It is optimized handle data that results from sophisticated magneto-hydrodynamic simulations. The main purpose of the code prepare analyze multi-wavelength continuum measurements in context magnetic field studies interstellar medium. An exemplary application...
We report the simultaneous measurement of structural and electronic components metal-insulator transition (MIT) VO2 using electron photoelectron spectroscopies microscopies. show that these evolve over different temperature scales, are separated by an unusual monocliniclike metallic phase. Our results provide conclusive evidence new phase, recently identified in high-pressure nonequilibrium measurements, is accessible thermodynamic at ambient pressure, we discuss implications observations on...
The disks around Herbig Ae/Be stars are commonly divided into group I and II based on their far-infrared spectral energy distribution, the common interpretation for that is flared flat disks. Recent observations suggest many flaring have gaps, whereas thought to be gapless. different groups of objects can expected structural signatures in high-angular-resolution data. Over past 10 years, MIDI instrument Very Large Telescope Interferometer has collected several tens protoplanetary We model...
Dust grains with sizes around (sub)mm are expected to couple only weakly the gas motion in regions beyond 10 au of circumstellar disks. In this work, we investigate influence spatial distribution such on appearance magnetized protoplanetary We perform non-ideal global 3D magneto-hydrodynamic stratified disk simulations including particles different (50 micron 1 cm), using a Lagrangian particle solver. calculate dust temperature distribution, dynamically coupled submicron-sized grains, and...