Gert Finger
A5021019201- Astronomy and Astrophysical Research
- Adaptive optics and wavefront sensing
- CCD and CMOS Imaging Sensors
- Stellar, planetary, and galactic studies
- Advanced Semiconductor Detectors and Materials
- Infrared Target Detection Methodologies
- Calibration and Measurement Techniques
- Astronomical Observations and Instrumentation
- Advanced Optical Sensing Technologies
- Spectroscopy and Laser Applications
- Semiconductor Lasers and Optical Devices
- Astrophysical Phenomena and Observations
- Astrophysics and Star Formation Studies
- Superconducting and THz Device Technology
- Astro and Planetary Science
- Gamma-ray bursts and supernovae
- Particle Detector Development and Performance
- Antenna Design and Optimization
- Advanced optical system design
- Medical Imaging Techniques and Applications
- Optical Systems and Laser Technology
- Optical Wireless Communication Technologies
- Semiconductor Quantum Structures and Devices
- Building Energy and Comfort Optimization
- Atmospheric Ozone and Climate
Max Planck Institute for Extraterrestrial Physics
2022-2024
European Southern Observatory
2006-2020
Leibniz Institute for Astrophysics Potsdam
2014
University of Groningen
2014
Sto (Germany)
2007
Observatoire de Paris
2006
European Southern Observatory
2006
École Polytechnique Fédérale de Lausanne
1982
ETH Zurich
1981
Infrared Laboratories (United States)
1979
X-shooter is the first 2nd generation instrument of ESO Very Large Telescope(VLT). It a very efficient, single-target, intermediate-resolution spectrograph that was installed at Cassegrain focus UT2 in 2009. The covers, single exposure, spectral range from 300 to 2500 nm. designed maximize sensitivity this through dichroic splitting three arms with optimized optics, coatings, dispersive elements and detectors. operates intermediate resolution (R~4,000 - 17,000, depending on wavelength slit...
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...
GRAVITY is a new instrument to coherently combine the light of European Southern Observatory Very Large Telescope Interferometer form telescope with an equivalent 130 m diameter angular resolution and collecting area 200 m$^2$. The comprises fiber fed integrated optics beam combination, high spectroscopy, built-in analysis control, near-infrared wavefront sensing, phase-tracking, dual operation laser metrology [...]. This article gives overview reports on performance first astronomical...
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...
Tight relationships exist in the local universe between central stellar properties of galaxies and mass their supermassive black hole. These suggest holes co-evolve, with main regulation mechanism being energetic feedback from accretion onto hole during its quasar phase. A crucial question is how relationship evolves time; a key epoch to probe this at peaks star formation growth 8-12 billion years ago (redshifts 1-3). Here we report dynamical measurement luminous redshift 2, look back time...
CRIRES is a cryogenic, pre-dispersed, infrared echelle spectrograph designed to provide resolving power lambda/(Delta lambda) of 10<sup>5</sup> between 1 and 5mu m at the Nasmyth focus B 8m VLT unit telescope #1 (Antu). A curvature sensing adaptive optics system feed used minimize slit losses diffraction limited spatial resolution along slit. mosaic 4 Aladdin~III InSb-arrays packaged on custom-fabricated ceramics boards has been developed. This provides for an effective 4096x512 pixel focal...
The Adaptive Optics NIR Instrument NAOS-CONICA has been commissioned at the VLT (UT4) between November 2001 and March 2002. After summarizing observational capabilities of this multimode instrument in combination with powerful AO-system, we will present first on sky results instrumental performance for several non-direct imaging modes: High spatial resolution slit-spectroscopy optical thermal region tested. For compact sources below 2 arcsec extension, Wollaston prism polarimetry is used....
The 4MOST consortium is currently halfway through a Conceptual Design study for ESO with the aim to develop wide-field (>3 square degree, goal >5 degree), high-multiplex (>1500 fibres, 3000 fibres) spectroscopic survey facility an 4m-class telescope (VISTA). will run permanently on perform 5 year public yielding more than 20 million spectra at resolution R~5000 ({\lambda}=390-1000 nm) and 2 R~20,000 (395-456.5 nm & 587-673 nm). design especially intended complement three key all-sky,...
We describe the design, development, and performance of HAWK-I, new High-Acuity Wide-field K-band Imager for ESO's Very Large Telescope, which is equipped with a mosaic four 2 k arrays operates from 0.9-2.4 μm over 0.1´´ pixels. A novel feature use all reflective optics that, together filters excellent throughput detectors high quantum efficiency, has yielded an extremely throughput. Commissioning science verification observations have already delivered variety deep images that demonstrate...
The 4MOST[1] instrument is a concept for wide-field, fibre-fed high multiplex spectroscopic facility on the ESO VISTA telescope designed to perform massive (initially >25x106 spectra in 5 years) combined all-sky public survey. main science drivers are: Gaia follow up of chemo-dynamical structure Milky Way, stellar radial velocities, parameters and abundances, chemical tagging; eROSITA cosmology with x-ray clusters galaxies, X-ray AGN/galaxy evolution z~5, Galactic sources resolving edge;...
4MOST is a wide-field, high-multiplex spectroscopic survey facility under development for the VISTA telescope of European Southern Observatory (ESO). Its main science drivers are in fields galactic archeology, high-energy physics, galaxy evolution and cosmology. will particular provide complements to large area surveys coming from space missions like Gaia, eROSITA, Euclid, PLATO ground-based facilities VISTA, VST, DES, LSST SKA. The baseline concept features 2.5 degree diameter field-of-view...
The only way to overcome the CMOS noise barrier of near infrared sensors used for wavefront sensing and fringe tracking is amplification photoelectron signal inside pixel by means avalanche gain. In 2007 ESO started a program at Selex develop electron photodiode arrays (eAPD) tracking. first step cutoff wavelength was reduced from 4.5 micron 2.5 in order verify that dark current scales with bandgap can be less than one electron/ms, value required sensing. growth technology liquid phase...
HARMONI is the E-ELT's first light visible and near-infrared integral field spectrograph. It will provide four different spatial scales, ranging from coarse spaxels of 60 × 30 mas best suited for seeing limited observations, to 4 that Nyquist sample diffraction point spread function E-ELT at wavelengths. Each spaxel scale may be combined with eleven spectral settings, a range resolving powers (R ~3500, 7500 20000) instantaneous wavelength coverage spanning 0.5 – 2.4 μm instrument. In autumn...
The performance of the current high speed near infrared HgCdTe sensors operating in fringe trackers, wavefront and tip-tilt is severely limited by noise silicon readout interface circuit (ROIC), even if state-of-the- art CMOS designs are used. A major improvement can only be achieved amplification photoelectron signal directly at point absorption means avalanche gain inside pixel. Unlike silicon, offers noiseless gain. This has been verified with LPE grown 320x256 pixel...
HAWK-I (High Acuity, Wide field K-band Imaging) is a 0.9 μm - 2.5 wide near infrared imager designed to sample the best images delivered over large of 7.5 arcmin x arcmin. cryogenic instrument be installed on one Very Large Telescope Nasmyth foci. It employs catadioptric design and focal plane equipped with mosaic four HAWAII 2 RG arrays. Two filter wheels allow insert broad band narrow filters. The remain compatible an adaptive secondary system under study for VLT.
HARMONI is a visible and near-infrared (0.47 to 2.45 μm) integral field spectrometer, providing the E-ELT's core spectroscopic capability, over range of resolving powers from R (≡λ/Δλ)~500 R~20000. The instrument provides simultaneous spectra ~32000 spaxels at near-IR wavelengths, arranged in √2:1 aspect ratio contiguous field. conceived as workhorse instrument, addressing many key science cases, will exploit scientific potential its early years, starting first light. spatial pixel (spaxel)...
In 2007 ESO started a program at SELEX (now LEONARDO) to develop noiseless near infrared HgCdTe electron avalanche photodiode arrays (eAPD)[1][2][3]. This eAPD technology is only way overcome the limiting CMOS noise barrier of sensors used for wavefront sensing and fringe tracking. After several development cycles solid state engineering techniques which can be easily applied chosen growth metal organic vapour phase epitaxy (MOVPE), have matured resulted in SAPHIRA arrays. They format...
The GRAVITY instrument has been revolutionary for near-infrared interferometry by pushing sensitivity and precision to previously unknown limits. With the upgrade of Very Large Telescope Interferometer (VLTI) in GRAVITY+, these limits will be pushed even further, with vastly improved sky coverage, as well faint-science high-contrast capabilities. This includes implementation wide-field off-axis fringe-tracking, new adaptive optics systems on all Unit Telescopes, laser guide stars an upgraded...
Since adaptive optics on large telescopes provides almost diffraction limited resolution, Nyquist sampling of moderate fields requires format arrays. Because substrate sizes there is a tendency to shrink the pixel size extend array beyond 2Kx2K. However, with smaller coupling capacitance between neighboring pixels becomes more important and its effect performance basic parameters arrays has be analyzed. Therefore, techniques measure conversion gain will presented. The comparison method...
MATISSE is foreseen as a mid-infrared spectro-interferometer combining the beams of up to four UTs/ATs Very Large Telescope Interferometer (VLTI) European Southern Observatory. The related science case study demonstrates enormous capability new generation beam combiner. will constitute an evolution two-beam interferometric instrument MIDI. MIDI very successful which offers perfect combination spectral and angular resolution. New characteristics present in give access mapping distribution...
Recently ESO has commissioned the HAWK-I camera which is equipped with a 2×2 mosaic of λc~ 2.5 µm HAWAII-2RG arrays. The arrays have high quantum efficiency and achieve photon shot noise limited performance on telescope. Using reference pixels it can be shown that readout for most by MBE grown HgCdTe material not multiplexer or data acquisition chain. Results obtained guide window will presented. Inter-channel crosstalk fringing in detector substrate discussed. dynamic range detectors...
We observe the HMXB BP Cru using interferometry in near-infrared K band with VLTI/GRAVITY. Continuum visibilities are at most partially resolved, consistent predicted size of hypergiant. Differential visibility amplitude ($\Delta |V| \sim 5\%$) and phase \phi 2 \deg$) signatures observed across HeI $2.059 \mu$m Br$\gamma$ lines, latter seen strongly emission, unusual for donor star's spectral type. For a baseline $B 100$m, differential RMS $\sim 0.2 \deg$ corresponds to an astrometric...