Thomas Dauser
A5036973720- Astrophysical Phenomena and Observations
- Pulsars and Gravitational Waves Research
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Galaxies: Formation, Evolution, Phenomena
- Glioma Diagnosis and Treatment
- Mechanics and Biomechanics Studies
- Particle Detector Development and Performance
- High-pressure geophysics and materials
- Superconducting and THz Device Technology
- Astronomy and Astrophysical Research
- Particle Accelerators and Free-Electron Lasers
- Astronomical Observations and Instrumentation
- Radio Astronomy Observations and Technology
- Calibration and Measurement Techniques
- Stellar, planetary, and galactic studies
- Advanced X-ray Imaging Techniques
- Superconducting Materials and Applications
- Brain Metastases and Treatment
- Radiation Therapy and Dosimetry
- Relativity and Gravitational Theory
- Microtubule and mitosis dynamics
- Adaptive optics and wavefront sensing
- Magnetic confinement fusion research
- Hedgehog Signaling Pathway Studies
Sonneberg Observatory
2015-2025
Friedrich-Alexander-Universität Erlangen-Nürnberg
2015-2024
RUAG (Germany)
2024
California Institute of Technology
2024
University of Utah
2023
Texas Children's Hospital
2007-2021
ETH Zurich
2021
University of Würzburg
2021
RWTH Aachen University
2021
TU Dortmund University
2021
eROSITA (extended ROentgen Survey with an Imaging Telescope Array) is the primary instrument on Spectrum-Roentgen-Gamma (SRG) mission, which was successfully launched July 13, 2019, from Baikonour cosmodrome. After commissioning of and a subsequent calibration performance verification phase, started survey entire sky December 2019. By end 2023, eight complete scans celestial sphere will have been performed, each lasting six months. At this program, all-sky in soft X-ray band (0.2--2.3\,keV)...
X-ray reflection models are used to constrain the properties of accretion disk, such as degree ionization gas and elemental abundances. In combination with general relativistic ray tracing codes, additional parameters like spin black hole inclination system can be determined. However, current for studies only provide angle-averaged solutions flux reflected at surface disk. Moreover, emission angle photons changes over disk due light bending. To overcome this simplification, we have...
X-ray irradiation of the accretion disc leads to strong reflection features, which are then broadened and distorted by relativistic effects. We present a detailed, general approach model this for different geometries primary source. These include standard point source on rotational axis as well more jet-like sources, radially elongated accelerating. Incorporating code in relline line emission, shape any configuration can be predicted. study how affect determination spin black hole. Broad...
We present an extended scheme for the calculation of profiles emission lines from accretion discs around rotating black holes.The includes with angular momenta which are parallel and antiparallel respect to hole's momentum, as both configurations assumed be stable.We discuss line shapes such a code modelling observational data this in X-ray analysis programs.Based on Green's function approach, arbitrary radius dependence disc emissivity limb darkening laws can easily taken into account,...
Abstract In many active galaxies, the X-ray reflection features from innermost regions of accretion disc are relativistically distorted. This distortion allows us to measure parameters black hole such as its spin. The ratio in flux between direct and reflected radiation, so-called fraction, is determined directly geometry location primary source radiation. We calculate fraction lamp post order determine maximal possible value for a given show that high fractions excess two only rapidly...
We present a new and complete library of synthetic spectra for modeling the component emission that is reflected from an illuminated accretion disk. The were computed using updated version our code xillver incorporates routines richer atomic database. offer in form table model extensive grid reflection models cover wide range parameters. Each individual characterized by photon index Γ illuminating radiation, ionization parameter ξ at surface disk (i.e., ratio X-ray flux to gas density), iron...
The X-ray Integral Field Unit (X-IFU) is the high resolution spectrometer of ESA Athena observatory. Over a field view 5' equivalent diameter, it will deliver spectra from 0.2 to 12 keV with spectral 2.5 eV up 7 on ∼ 5" pixels. X-IFU based large format array super-conducting molybdenum-gold Transition Edge Sensors cooled at 90 mK, each coupled an absorber made gold and bismuth pitch 249 μm. A cryogenic anti-coincidence detector located underneath prime TES enables non background be reduced....
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...
Abstract Quasi-periodic eruptions (QPEs) are a recently identified class of X-ray transient associated with tidal disruption events by supermassive black holes, and for which there multiple possible explanations. In this paper we present simple model requires the hole be spinning, misaligned accretion flow (both conditions almost certainly met) that rate is few times Eddington limit. We speculate resulting Lense-Thirring torques force disc entrained outflows to precess, leading increased...
The only relativistic reflection model that implements a parameter relating the intensity incident on an accretion disk to observed is relxill. used in earlier versions of this model, referred as strength, unsatisfactory, and it has been superseded by provides insight into geometry, namely fraction. fraction defined ratio coronal illuminating reaches observer. relxill combines general ray-tracing code photoionization compute component radiation reflected from illuminated internal source....
Current models of the spectrum X-rays reflected from accretion disks around black holes and other compact objects are commonly calculated assuming that density disk atmosphere is constant within several Thomson depths irradiated surface. An important simplifying assumption these ionization structure gas completely specified by a single, fixed value parameter $\xi$, which ratio incident flux to density. The typically at $n_e=10^{15}$ cm$^{-3}$. Motivated observations, we consider higher...
We present 3-50 keV NuSTAR observations of the AGN Mrk 335 in a very low flux state. The spectrum is dominated by strong features at energies iron line 5-7 and Compton hump from 10-30 keV. source variable during observation, with variability concentrated energies, which suggesting either relativistic reflection or absorption scenario. In this work we focus on interpretation, making use new models that self consistently calculate fraction, blurring angle-dependent for different coronal...
The X-ray Integral Field Unit (X-IFU) on board the Advanced Telescope for High-ENergy Astrophysics (Athena) will provide spatially resolved high-resolution spectroscopy from 0.2 to 12 keV, with 5 arc second pixels over a field of view minute equivalent diameter and spectral resolution 2.5 eV up 7 keV. In this paper, we first review core scientific objectives Athena, driving main performance parameters X-IFU, namely resolution, view, effective area, count rate capabilities, instrumental...
Central nervous system Langerhans cell histiocytosis (CNS-LCH) brain involvement may include mass lesions and/or a neurodegenerative disease (LCH-ND) of unknown etiology. The goal this study was to define the mechanisms pathogenesis that drive CNS-LCH.Cerebrospinal fluid (CSF) biomarkers including CSF proteins and extracellular BRAFV600E DNA were analyzed in from patients with CNS-LCH compared tumors other conditions. Additionally, presence tested peripheral mononuclear blood cells (PBMCs)...
We discuss the application of simple relativistically-blurred X-ray reflection models to determination spin and inner radius disc in accreting black holes. Observationally, nature corona is uncertain a priori, but robust disk can be made when emissivity index tightly constrained. When well illuminated, hole also determined. Using modelling derived from ray tracing, we show that truncation requires location coronal source quasi-static at height less than disc. Robust measurements require...
We present a high density disc reflection spectral analysis of sample 17 Seyfert 1 galaxies to study the inner densities at different black hole mass scales and accretion rates. All available XMM-Newton observations in archive are used. OM optical/UV band used estimate their find that 65% sources our show significantly higher than 1e15 cm^{-3}, which was assumed previous reflection-based analyses. The best-fit an anti-correlation with rate. High model can successfully explain soft excess...
We analyze {\it simultaneously} six composite RXTE} spectra of GX 339--4 in the hard state comprising 77 million counts collected over 196 ks. The source are ordered by luminosity and spanthe range 1.6\% to 17\% Eddington luminosity. Crucially, using our new tool {\tt pcacorr}, we re-calibrate data a precision 0.1\%, an order magnitude improvement all earlier work. Using advanced reflection model relxill}, target strong features component emission reflected from disk, namely,...