A5088802164- Astrophysical Phenomena and Observations
- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Medical Imaging Techniques and Applications
- Gamma-ray bursts and supernovae
- Advanced X-ray and CT Imaging
- Astronomical Observations and Instrumentation
- Archaeology and ancient environmental studies
- Paleopathology and ancient diseases
- Astro and Planetary Science
- Advanced Measurement and Metrology Techniques
- Astronomy and Astrophysical Research
- Pleistocene-Era Hominins and Archaeology
- Advanced X-ray Imaging Techniques
- Gas Dynamics and Kinetic Theory
- Scientific Measurement and Uncertainty Evaluation
- Forensic Anthropology and Bioarchaeology Studies
- Cultural Heritage Materials Analysis
- Welding Techniques and Residual Stresses
- Advanced Electron Microscopy Techniques and Applications
- Concrete Corrosion and Durability
- Advanced ceramic materials synthesis
- History and Developments in Astronomy
- Historical Astronomy and Related Studies
- Galaxies: Formation, Evolution, Phenomena
Zuse Institute Berlin
2019-2021
Thermo Fisher Scientific (Germany)
2017-2021
Federal Institute For Materials Research and Testing
2010-2019
Bluegrass Advanced Materials (United States)
2014
Physikalisch-Technische Bundesanstalt
2010
Leibniz Institute for Astrophysics Potsdam
2001-2009
University of Potsdam
2005
Abstract STELLA is a robotic observatory with two fully automatic telescopes (STELLA‐I and STELLA‐II) located at the Teide Observatory in Tenerife, Spain. Not only are but also entire observatory, no human presence needed for observing ‐ not even remote control. STELLA‐I supports high‐resolution, fiber‐fed benchmounted echelle spectrograph wide‐field CCD imaging photometer while STELLA‐II feeds similar wide‐band testbed prototype adaptive optics telescopes. The first telescope scheduled...
We present time-series optical photometry of five new cataclysmic variables (CVs) identified by the Hamburg Quasar Survey (HQS). The deep eclipses observed in HS 0129+2933 (= TT Tri), 0220+0603 and 0455+8315 provided very accurate orbital periods 3.35129827(65), 3.58098501(34) 3.56937674(26) h, respectively. 0805+3822 shows grazing has a likely period 3.2169(2) h. Time-resolved spectroscopy CVs (with exception 0805+3822) is also presented. Radial velocity studies Balmer emission lines an...
We present follow-up spectroscopy and photometry of 11 post-common envelope binary (PCEB) candidates identified from multiple Sloan Digital Sky Survey (SDSS) in an earlier paper. Radial velocity measurements using the Na i λλ8183.27, 8194.81 absorption doublet were performed for nine these systems provided six orbital periods range Porb= 2.7– 17.4 h. Three PCEB did not show significant radial variations data, we discuss implications use SDSS alone to identify PCEBs. Differential confirmed...
Archaeological bone, ivory and antler, as well objects manufactured from them, are largely studied to extract much information possible these materials. Among others, one key question in archaeology is the exact identification of material. Even if different kinds osseous material seems be trivial many cases, it can a difficult issue when small, heavily carved more or less altered ancient concerned. This study was focused on determination parameters allowing distinction archaeological ivory,...
Macroscopic, periodic, dark and bright patterns are observed on sections of elephant tusk, in the dentin part (ivory). The motifs—also called Schreger pattern—vary depending orientation tusk: perpendicular to tusk axis, a checkerboard pattern is present whereas longitudinal it, alternating stripes observed. This has been used identify mammoth ivory archeological artifacts informs continuous tissue growth mechanisms tusk. However, its origin, assumed be related 3D structure empty microtubules...
Achieving traceability is crucial for complex measurement techniques, especially coordinate measuring machines (CMMs). For CMMs using tactile probes, can certain measurements be achieved model-based uncertainty budgets. Up to now, simula-tions could used applicable only CMM of regular geometries, but are available as an add-on different CMMs. This procedure accepted by guidelines and inter-national standards (VDI/VDE 2617-7, supplement 1 [1] GUM). Furthermore, empirical ap-proaches assess...
Abstract Most knowledge about the structure, function, and evolution of early compound eyes is based on investigations in trilobites. However, these studies dealt mainly with cuticular lenses little was known internal anatomy. Only recently some data crystalline cones retinula cells were reported for a Cambrian trilobite species. Here, we describe eye structures two other genera. The Ordovician Asaphus sp. reveals preserved situated underneath lenses. same true Devonian species Archegonus (...
Aims.We report the discovery of five new dwarf novae that were spectroscopically identified in Hamburg Quasar Survey (HQS), and discuss properties sample from HQS.
Decent optical photometry of the canditate magnetic CV Paloma has uncovered three persistent periods at 157, 146, and 136 min, which we interpret as manifestation orbital motion system, white dwarf's spin, a related side-band frequency other two. All periodicities are caused by double-humped modulation about 1 mag appearing only certain fractions beat cycle, it probably originates from one or two accretion spots. Our data is consistent with plausible solutions, spin period being either 146...
We report on the discovery of a very low mass (VLM) star in solar neighborhood, originally identified as an optical counterpart flaring X-ray source detected ROSAT All-Sky survey. Optical spectroscopy and infrared photometry consistently reveal spectral type distance ≈ pc. The 1RXS J115928.5-524717 shows large proper motion /year. is fourth object among VLM stars displaying huge flare, reaching unprecedent value .
We present phase-resolved, high-resolution (1.3 Å) spectroscopy of the brightest near-synchronous polar BY Cam taken on two different occasions in 1998 and 1999. The first tomographic study such a system reveals line emission spread out over large velocity range forming crescent at negative vy velocities Doppler maps. In contrast to majority synchronous AM Her systems there is only weak indication for presence focused accretion stream. These facts suggest that matter accreted via an extended...
Archival X-ray observations of EF Eridani obtained in a low state revealed distinct detections at luminosity 2 1029 erg s-1, three orders magnitude below its high value. The plasma temperature was found to be as keV, factor 10 the state. X-ray/UV/IR spectral energy distribution suggests faint residual accretion rather than coronal emission being responsible for low-state emission. Eri thus showed clear transition from shock-dominated cyclotron-dominated From optical/UV we re-determine...
Aims. We study the timing and spectral properties of intermediate polar MU Camelopardalis (1RXS J062518.2+733433) to determine accretion modes geometry from multi-wavelength, multi-epoch observational data.
Based on high-resolution optical spectroscopy in the blue and near infra-red spectral range, we derived velocity images (Doppler tomograms) of mass-donating secondary star accretion stream long-period eclipsing polar V1309 Ori (RX J0515.41+0104.6). Combined with HST-spectroscopy high time resolution photometry were able to derive main system parameters determine geometry binary. The length eclipse white dwarf is s, mass ratio -1.63, orbital inclination -. surface could be resolved Doppler...
We present the results of 50 hours time-resolved R-band photometry ROSAT all-sky survey source 1RXS J062518.2+733433. The was identified by Wei et al. ([CITE]) as a cataclysmic variable. Our photometry, performed in 10 nights between February 11, 2003, and March 21, reveals two stable periodicities at 19.7874 283.118 min, which are probable spin orbital periods binary. therefore classify J062518.2+733433 an intermediate polar. Analysis RASS X-ray observations reveal variability 100% flux...
(Abridged). The cataclysmic binary V405 Peg, originally discovered as ROSAT Bright Source (RBS) 1955 (= 1RXS J230949.6+213523), shows a strong contribution from late-type secondary star in its optical spectrum, which led Schwope et al. to suggest it be among the nearest binaries. We present extensive observations of Peg. Time-series spectroscopy orbital period, Porb, 0.1776469(7) d 4.2635 hr), or 5.629 cycle/d. classify M3 - M4.5. Astrometry with MDM 2.4m telescope gives parallax 7.2 +- 1.1...