C. Straubmeier
A5006047518- Adaptive optics and wavefront sensing
- Astrophysical Phenomena and Observations
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Pulsars and Gravitational Waves Research
- Astronomical Observations and Instrumentation
- Galaxies: Formation, Evolution, Phenomena
- Astro and Planetary Science
- Optical Systems and Laser Technology
- Calibration and Measurement Techniques
- Advanced Measurement and Metrology Techniques
- Mechanics and Biomechanics Studies
- Advanced optical system design
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Optical measurement and interference techniques
- Radio Astronomy Observations and Technology
- Geophysics and Gravity Measurements
- Spectroscopy and Laser Applications
- Heat Transfer Mechanisms
- History and Developments in Astronomy
- Atmospheric Ozone and Climate
- High-pressure geophysics and materials
- Relativity and Gravitational Theory
University of Cologne
2015-2024
Max Planck Institute for Extraterrestrial Physics
2000-2024
CBS International Business School
2022
Max Planck Society
2001-2021
Centre National de la Recherche Scientifique
2020
Observatoire de Paris
2018-2020
Sorbonne Université
2020
Université Paris Cité
2020
Laboratoire d’études spatiales et d’instrumentation en astrophysique
2020
Max Planck Institute for Radio Astronomy
2017
The highly elliptical, 16-year-period orbit of the star S2 around massive black hole candidate Sgr A ✻ is a sensitive probe gravitational field in Galactic centre. Near pericentre at 120 AU ≈ 1400 Schwarzschild radii, has an orbital speed ≈7650 km s −1 , such that first-order effects Special and General Relativity have now become detectable with current capabilities. Over past 26 years, we monitored radial velocity motion on sky S2, mainly SINFONI NACO adaptive optics instruments ESO Very...
The stars orbiting the compact radio source Sgr A* in Galactic Centre are precision probes of gravitational field around closest massive black hole. In addition to adaptive optics assisted astrometry (with NACO / VLT) and spectroscopy SINFONI VLT, NIRC2 Keck GNIRS Gemini) over three decades, since 2016/2017 we have obtained 30-100 mu-as with four-telescope interferometric beam combiner GRAVITY VLTI reaching a sensitivity mK = 20 when combining data from one night. We present simultaneous...
The GRAVITY instrument on the ESO VLTI pioneers field of high-precision near-infrared interferometry by providing astrometry at $10 - 100\,\mu$as level. Measurements such high precision crucially depend control systematic effects. Here, we investigate how aberrations introduced small optical imperfections along path from telescope to detector affect astrometry. We develop an analytical model that describes impact measurement complex visibilities. Our formalism accounts for pupil-plane and...
We present new astrometric and polarimetric observations of flares from Sgr A* obtained with GRAVITY, the near-infrared interferometer at ESO's Very Large Telescope Interferometer (VLTI), bringing total sample well-covered to four ones six, where we have for two good coverage in both domains. All show clockwise motion plane sky a period around an hour, polarization vector rotates by one full loop same time. Given apparent similarities flares, common fit, taking into account absence strong...
By using the GRAVITY instrument with near-infrared (NIR) Very Large Telescope Interferometer (VLTI), structure of broad (emission-)line region (BLR) in active galactic nuclei (AGNs) can be spatially resolved, allowing central black hole (BH) mass to determined. This work reports new NIR VLTI/GRAVITY interferometric spectra for four type 1 AGNs (Mrk 509, PDS 456, Mrk 1239, and IC 4329A) resolved broad-line emission. Dynamical modelling data constrains BLR radius BH measurements our targets...
Aims.The centre of the Milky Way is nearest nucleus a galaxy and offers unique possibility to study structure dynamics dense stellar cluster around super-massive black hole.
To date, infrared interferometry at best achieved contrast ratios of a few times $10^{-4}$ on bright targets. GRAVITY, with its dual-field mode, is now capable high observations, enabling the direct observation exoplanets. We demonstrate technique HR8799, young planetary system composed four known giant used GRAVITY fringe tracker to lock fringes central star, and integrated off-axis HR8799e planet situated 390 mas from star. Data reduction included post-processing remove flux leaking star...
Context. β Pictoris is arguably one of the most studied stellar systems outside our own. Some 30 yr observations have revealed a highly-structured circumstellar disk, with rings, belts, and giant planet: b. However very little known about how this system came into being. Aims. Our objective to estimate C/O ratio in atmosphere b obtain an dynamical mass planet, as well refine its orbital parameters using high-precision astrometry. Methods. We used GRAVITY instrument four 8.2 m telescopes Very...
We present K-band interferometric observations of the PDS 70 protoplanets along with their host star using VLTI/GRAVITY. obtained spectra and 100 $\mu$as precision astrometry both b c in two epochs, as well spatially resolving hot inner disk around star. Rejecting unstable orbits, we found a nonzero eccentricity for $0.17 \pm 0.06$, near-circular orbit c, an orbital configuration that is consistent planets migrating into 2:1 mean motion resonance. Enforcing dynamical stability, 95% upper...
We present near-infrared interferometric data on the Seyfert 2 galaxy NGC 1068, obtained with GRAVITY instrument European Southern Observatory Very Large Telescope Interferometer. The extensive baseline coverage from 5 to 60 M\lambda allowed us reconstruct a continuum image of nucleus an unrivaled 0.2 pc resolution in K-band. find thin ring-like structure emission radius r = 0.24+/-0.03 pc, inclination i 70+/-5 deg, position angle PA -50+/-4 and h/r < 0.14, which we associate dust...
Methods used to detect giant exoplanets can be broadly divided into two categories: indirect and direct. Indirect methods are more sensitive planets with a small orbital period, whereas direct detection is orbiting at large distance from their host star. %, thus on long period. This dichotomy makes it difficult combine the techniques single target once. Simultaneous measurements made by offer possibility of determining mass luminosity method testing formation models. Here, we aim show how...
Infrared observations of Sgr A* probe the region close to event horizon black hole at Galactic center. These can constrain properties low-luminosity accretion as well that itself. The GRAVITY instrument ESO VLTI has recently detected continuous circular relativistic motion during infrared flares which been interpreted orbital near horizon. Here we analyze astrometric data from these flares, taking into account effects out-of-plane and shear material hole. We have developed a new code predict...
Using VLTI/GRAVITY and SINFONI data, we investigate the subparsec gas dust structure around nearby type 1 active galactic nucleus (AGN) hosted by NGC 3783. The K -band coverage of GRAVITY uniquely allows simultaneous analysis size kinematics broad line region (BLR), near-infrared(near-IR)-continuum-emitting hot dust, coronal (CLR). We find BLR, probed through Br γ emission, to be well described a rotating, thick disc with radial distribution clouds peaking in inner region. In our BLR model,...
Aims. We aim to demonstrate that the presence and mass of an exoplanet can now be effectively derived from astrometry another exoplanet. Methods. combined previous β Pictoris b with a new set observations GRAVITY interferometer. The orbital motion is fit using Markov chain Monte Carlo simulations in Jacobi coordinates. inner planet, c, was also reobserved at separation 96 mas, confirming estimations. Results. From planet only, we (i) detect c (ii) constrain its 10.04 −3.10 +4.53 M Jup . If...
With four companions at separations from 16 to 71 au, HR 8799 is a unique target for direct imaging, presenting an opportunity the comparative study of exoplanets with shared formation history. Combining new VLTI/GRAVITY observations obtained within ExoGRAVITY program archival data, we perform systematic atmospheric characterisation all planets. We explore different levels model flexibility understand temperature structure, chemistry and clouds each planet using both petitRADTRANS retrievals...
Context. The GRAVITY beam-combiner at the Very Large Telescope Interferometer has recently made important contributions to many different fields of astronomy, from observations Galactic centre study massive stars, young stellar objects, exoplanet atmospheres, and active galactic nuclei. These achievements were only possible by development several key technologies, including reliable high-performance fringe trackers. systems compensate for disturbances ranging atmospheric turbulence...
We report on the first simultaneous near-infrared/X-ray detection of Sgr A* counterpart associated with massive 3– black hole at center Milky Way. The observations have been carried out using NACO adaptive optics (AO) instrument European Southern Observatory's Very Large Telescope and ACIS-I aboard Chandra X-ray Observatory. also quasi-simultaneous a wavelength 3.4 mm Berkeley-Illinois-Maryland Association (BIMA) array. A flare was detected in X-domain an excess 2–8 keV luminosity about...
We present a comprehensive data description for Ks-band measurements of Sgr A*. characterize the statistical properties variability A* in near-infrared, which we find to be consistent with single-state process forming power-law distribution flux density. discover linear rms-flux relation flux-density range up 12 mJy on timescale 24 minutes. This and density implies phenomenological, formally non-linear model can simulate observed extrapolate its behavior higher levels longer timescales....
The GRAVITY instrument has been commissioned on the VLTI during 2016 and is now available to astronomical community. It first optical interferometer capable of observing sources as faint magnitude 19 in K-band. This possible thanks fringe tracker which compensates differential piston based measurements a brighter off-axis reference source. goal this paper consign main developments made context tracker. could serve basis for future tracking systems. therefore covers all aspects tracker, from...
We present new near-infrared VLTI/GRAVITY interferometric spectra that spatially resolve the broad Br$\gamma$ emission line in nucleus of active galaxy IRAS 09149-6206. use these data to measure size region (BLR) and estimate mass central black hole. Using an improved phase calibration method reduces differential uncertainty 0.05 degree per baseline across spectrum, we detect a signal reaches maximum ~0.5 between continuum. This represents offset ~120 $\mu$as (0.14 pc) BLR centroid hot dust...