Publications (60)
Constraining the Nature of the PDS 70 Protoplanets with VLTI/GRAVITY
J. J. Wang, A. Vigan, S. Lacour +101
We present K-band interferometric observations of the PDS 70 protoplanets along with their host star using VLTI/GRAVITY. We obtained K-band spectra and 100 as precision astrome…
Direct confirmation of the radial-velocity planet Pic c
M. Nowak, S. Lacour, A. -M. Lagrange +90
Methods used to detect giant exoplanets can be broadly divided into two categories: indirect and direct. Indirect methods are more sensitive to planets with a small orbital period,…
Four-of-a-kind? Comprehensive atmospheric characterisation of the HR 8799 planets with VLTI/GRAVITY
E. Nasedkin, P. Mollière, S. Lacour +95
With four companions at separations from 16 to 71 au, HR 8799 is a unique target for direct imaging, presenting an opportunity for the comparative study of exoplanets with a shared…
V/Vmax statistic and Neo-Classic Cosmological Tests
L. Van Waerbeke, G. Mathez, Y. Mellier +2
A new cosmological test is derived, based on the distribution of individual V/Vmax in a complete redshift-limited sample of distant objects. The fundamental assumption is that, in…
MOLsphere and pulsations of the Galactic Center's red supergiant GCIRS 7 from VLTI/GRAVITY
GRAVITY Collaboration, G. RodrÃguez-Coira, T. Paumard +55
GCIRS 7, the brightest star in the Galactic central parsec, formed Myr ago together with dozens of massive stars in a disk orbiting the central black-hole. It has been argu…
A geometric distance measurement to the Galactic Center black hole with 0.3% uncertainty
R. Abuter, A. Amorim, M. Bauboeck +51
We present a 0.16% precise and 0.27% accurate determination of R0, the distance to the Galactic Center. Our measurement uses the star S2 on its 16-year orbit around the massive bla…
GRAVITY chromatic imaging of Eta Car's core
GRAVITY Collaboration, J. Sanchez-Bermudez, G. Weigelt +132
Eta Car is one of the most intriguing luminous blue variables in the Galaxy. Observations and models at different wavelengths suggest a central binary with a 5.54 yr period residin…
VLTI/GRAVITY Observations and Characterization of the Brown Dwarf Companion HD 72946 B
W. O. Balmer, L. Pueyo, T. Stolker +96
Tension remains between the observed and modeled properties of substellar objects, but objects in binary orbits, with known dynamical masses can provide a way forward. HD 72946 B i…
GRAVITY+ Wavefront Sensors: High-Contrast, Laser Guide Star, Adaptive Optics systems for the VLTI
G. Bourdarot, F. Eisenhauer, S. Yazıcı +53
We present the Wavefront Sensor units of the Gravity Plus Adaptive Optics (GPAO) system, which will equip all 8m class telescopes of the VLTI and is an instrumental part of the GRA…
High contrast at short separation with VLTI/GRAVITY: Bringing Gaia companions to light
N. Pourré, T. O. Winterhalder, J. -B. Le Bouquin +173
Since 2019, GRAVITY has provided direct observations of giant planets and brown dwarfs at separations of down to 95 mas from the host star. Some of these observations have provided…
Detection of the gravitational redshift in the orbit of the star S2 near the Galactic centre massive black hole
GRAVITY Collaboration, R. Abuter, A. Amorim +95
The highly elliptical, 16-year-period orbit of the star S2 around the massive black hole candidate Sgr A* is a sensitive probe of the gravitational field in the Galactic centre. Ne…
Polarimetry and Astrometry of NIR Flares as Event Horizon Scale, Dynamical Probes for the Mass of Sgr A*
The GRAVITY Collaboration, R. Abuter, N. Aimar +66
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…
A measure of the size of the magnetospheric accretion region in TW Hydrae
R. Garcia Lopez, A. Natta, A. Caratti o Garatti +69
Stars form by accreting material from their surrounding disks. There is a consensus that matter flowing through the disk is channelled onto the stellar surface by the stellar magne…
A catalogue of dual-field interferometric binary calibrators
M. Nowak, S. Lacour, R. Abuter +97
Dual-field interferometric observations with VLTI/GRAVITY sometimes require the use of a "binary calibrator", a binary star whose individual components remain unresolved by the int…
Where intermediate-mass black holes could hide in the Galactic Centre: A full parameter study with the S2 orbit
The GRAVITY Collaboration, O. Straub, M. Bauböck +59
In the Milky Way the central massive black hole, SgrA*, coexists with a compact nuclear star cluster that contains a sub-parsec concentration of fast-moving young stars called S-st…
Improving the astrometric performance of VLTI-PRIMA
J. Woillez, R. Abuter, L. Andolfato +18
In the summer of 2011, the first on-sky astrometric commissioning of PRIMA-Astrometry delivered a performance of 3 m'' for a 10 '' separation on bright objects, orders of magnitude…
Exomoon search with VLTI/GRAVITY around the substellar companion HD 206893 B
Q. Kral, J. Wang, J. Kammerer +130
Direct astrometric detection of exomoons remains unexplored. This study presents the first application of high-precision astrometry to search for exomoons around substellar compani…
Direct imaging discovery of a young giant planet orbiting on Solar System scales
T. Stolker, M. Samland, L. B. F. M. Waters +102
HD 135344 AB is a young visual binary system that is best known for the protoplanetary disk around the secondary star. The circumstellar environment of the A0-type primary star, on…
The mass of Beta Pictoris c from Beta Pictoris b orbital motion
S. Lacour, J. J. Wang, L. Rodet +96
We aim to demonstrate that the presence and mass of an exoplanet can now be effectively derived from the astrometry of another exoplanet. We combined previous astrometry of Pi…
First VLTI/GRAVITY Observations of HIP 65426 b: Evidence for a Low or Moderate Orbital Eccentricity
S. Blunt, W. O. Balmer, J. J. Wang +95
Giant exoplanets have been directly imaged over orders of magnitude of orbital separations, prompting theoretical and observational investigations of their formation pathways. In t…
Constraints on the Orbit of the Young Substellar Companion GQ Lup B from High-Resolution Spectroscopy and VLTI/GRAVITY Astrometry
Vidya Venkatesan, S. Blunt, J. J. Wang +99
Understanding the orbits of giant planets is critical for testing planet formation models, particularly at wide separations greater than 10 au where traditional core accretion beco…
Detection of faint stars near SgrA* with GRAVITY
GRAVITY Collaboration, R. Abuter, A. Amorim +58
The spin of the supermassive black hole that resides at the Galactic Centre can in principle be measured by accurate measurements of the orbits of stars that are much closer to Sgr…
The wind and the magnetospheric accretion onto the T Tauri star S Coronae Australis at sub-au resolution
R. Garcia Lopez, K. Perraut, A. Caratti o Garatti +70
To investigate the inner regions of protoplanetary disks, we performed near-infrared interferometric observations of the classical TTauri binary system S CrA. We present the first…
Reaching micro-arcsecond astrometry with long baseline optical interferometry; application to the GRAVITY instrument
S. Lacour, F. Eisenhauer, S. Gillessen +10
A basic principle of long baseline interferometry is that an optical path difference (OPD) directly translates into an astrometric measurement. In the simplest case, the OPD is equ…
Pure Luminosity Evolution Hypothesis for QSOs: From Luminosity Functions to Synthetic Catalogues
G. Mathez, L. Van Waerbeke, Y. Mellier +2
This paper describes the simulation of realistic Monte-Carlo extragalactic catalogues, aimed at comparing the behaviour of cosmological tests versus input parameters. QSO catalogue…
Detection of orbital motions near the last stable circular orbit of the massive black hole SgrA*
GRAVITY Collaboration, R. Abuter, A. Amorim +57
We report the detection of continuous positional and polarization changes of the compact source SgrA* in high states ('flares') of its variable near- infrared emission with the nea…
A dynamical measure of the black hole mass in a quasar 11 billion years ago
R. Abuter, F. Allouche, A. Amorim +124
Tight relationships exist in the local universe between the central stellar properties of galaxies and the mass of their supermassive black hole. These suggest galaxies and black h…
Combining Gaia and GRAVITY: Characterising five new Directly Detected Substellar Companions
T. O. Winterhalder, S. Lacour, A. Mérand +96
Precise mass constraints are vital for the characterisation of brown dwarfs and exoplanets. Here we present how the combination of data obtained by Gaia and GRAVITY can help enlarg…
Orbit and atmosphere of HIP 99770 b through the eyes of VLTI/GRAVITY
T. O. Winterhalder, J. Kammerer, S. Lacour +92
Context: Inferring the likely formation channel of giant exoplanets and brown dwarf companions from orbital and atmospheric observables remains a formidable challenge. Further and…
Using the motion of S2 to constrain scalar clouds around SgrA*
GRAVITY Collaboration, A. Foschi, R. Abuter +67
The motion of S2, one of the stars closest to the Galactic Centre, has been measured accurately and used to study the compact object at the centre of the Milky Way. It is commonly…
First Light for GRAVITY Wide: Large Separation Fringe Tracking for the Very Large Telescope Interferometer
GRAVITY+ Collaboration, :, R. Abuter +114
GRAVITY+ is the upgrade of GRAVITY and the Very Large Telescope Interferometer (VLTI) with wide-separation fringe tracking, new adaptive optics, and laser guide stars on all four 8…
First direct detection of an exoplanet by optical interferometry; Astrometry and K-band spectroscopy of HR8799 e
S. Lacour, M. Nowak, J. Wang +85
To date, infrared interferometry at best achieved contrast ratios of a few times on bright targets. GRAVITY, with its dual-field mode, is now capable of high contrast obs…
SINFONI in the Galactic Center: young stars and IR flares in the central light month
F. Eisenhauer, R. Genzel, T. Alexander +18
We report 75 milli-arcsec resolution, near-IR imaging spectroscopy within the central 30 light days of the Galactic Center [...]. To a limiting magnitude of K~16, 9 of 10 stars in…
Improved GRAVITY astrometric accuracy from modeling of optical aberrations
GRAVITY Collaboration, R. Abuter, A. Amorim +60
The GRAVITY instrument on the ESO VLTI pioneers the field of high-precision near-infrared interferometry by providing astrometry at the as level. Measurements at such…
Accretion-ejection morphology of the microquasar SS433 resolved at sub-au scale
GRAVITY Collaboration, P. -O. Petrucci, I. Waisberg +67
We present the first optical observation at sub-milliarcsecond (mas) scale of the microquasar SS 433 obtained with the GRAVITY instrument on the VLT interferometer. The 3.5 hour ex…
SINFONI - Integral Field Spectroscopy at 50 milli-arcsecond resolution with the ESO VLT
F. Eisenhauer, H. Bonnet, R. Abuter +21
SINFONI is an adaptive optics assisted near-infrared integral field spectrometer for the ESO VLT. The Adaptive Optics Module (built by the ESO Adaptive Optics Group) is a 60-elemen…
Deep Images of the Galactic Center with GRAVITY
GRAVITY Collaboration, R. Abuter, N. Aimar +65
Stellar orbits at the Galactic Center provide a very clean probe of the gravitational potential of the supermassive black hole. They can be studied with unique precision, beyond th…
Detection of Weak Lensing in the Fields of Luminous Radiosources
B. Fort, Y. Mellier, M. Dantel-Fort +2
We present a first attempt to reveal the possible existence of large foreground mass condensations directly responsible for the gravitational magnification of four distant luminous…
Sub-milliarcsecond Optical Interferometry of the HMXB BP Cru with VLTI/GRAVITY
GRAVITY Collaboration, I. Waisberg, J. Dexter +68
We observe the HMXB BP Cru using interferometry in the near-infrared K band with VLTI/GRAVITY. Continuum visibilities are at most partially resolved, consistent with the predicted…
First Light for GRAVITY: Phase Referencing Optical Interferometry for the Very Large Telescope Interferometer
GRAVITY Collaboration, R. Abuter, M. Accardo +130
GRAVITY is a new instrument to coherently combine the light of the European Southern Observatory Very Large Telescope Interferometer to form a telescope with an equivalent 130 m di…
The mass distribution in the Galactic Centre from interferometric astrometry of multiple stellar orbits
GRAVITY Collaboration, R. Abuter, N. Aimar +62
The stars orbiting the compact radio source Sgr A* in the Galactic Centre are precision probes of the gravitational field around the closest massive black hole. In addition to adap…
The Flux Distribution of Sgr A*
The GRAVITY Collaboration, R. Abuter, A. Amorim +54
The Galactic Center black hole Sagittarius A* is a variable NIR source that exhibits bright flux excursions called flares. The low-flux density turnover of the flux distribution is…
Using the motion of S2 to constrain vector clouds around SgrA*
GRAVITY Collaboration, A. Foschi, R. Abuter +53
The dark compact object at the centre of the Milky Way is well established to be a supermassive black hole with mass , but the nature…
Direct discovery of the inner exoplanet in the HD206893 system. Evidence for deuterium burning in a planetary-mass companion
S. Hinkley, S. Lacour, G. -D. Marleau +110
Long term precise radial velocity (RV) monitoring of the nearby star HD206893, as well as anomalies in the system proper motion, have suggested the presence of an additional, inner…
The ExoGRAVITY survey: A K-band spectral library of giant exoplanet and brown dwarf companions
J. Kammerer, T. O. Winterhalder, S. Lacour +106
Direct observations of exoplanet and brown dwarf companions with near-infrared interferometry, first enabled by the dual-field mode of VLTI/GRAVITY, provide unique measurements of…
Detection of the Schwarzschild precession in the orbit of the star S2 near the Galactic centre massive black hole
GRAVITY Collaboration, R. Abuter, A. Amorim +53
The star S2 orbiting the compact radio source Sgr A* is a precision probe of the gravitational field around the closest massive black hole (candidate). Over the last 2.7 decades we…
Peering into the formation history of beta Pictoris b with VLTI/GRAVITY long baseline interferometry
GRAVITY Collaboration, M. Nowak, S. Lacour +65
Our objective is to estimate the C/O ratio in the atmosphere of beta Pictoris b and obtain an estimate of the dynamical mass of the planet, as well as to refine its orbital paramet…
Estimation of the lateral mis-registrations of the GRAVITY + adaptive optics system
Anthony Berdeu, H. Bonnet, J. -B. Le Bouquin +16
Context. The GRAVITY+ upgrade implies a complete renewal of its adaptive optics (AO) systems. Its complex design, featuring moving components between the deformable mirrors and the…
Constraining particle acceleration in Sgr A* with simultaneous GRAVITY, Spitzer, NuSTAR and Chandra observations
R. Abuter, A. Amorim, M. Bauböck +81
We report the time-resolved spectral analysis of a bright near-infrared and moderate X-ray flare of Sgr A*. We obtained light curves in the -, -, and -bands in the mid- an…
Astrometric detection of a Neptune-mass candidate planet in the nearest M-dwarf binary system GJ65 with VLTI/GRAVITY
GRAVITY Collaboration, R. Abuter, A. Amorim +65
The detection of low-mass planets orbiting the nearest stars is a central stake of exoplanetary science, as they can be directly characterized much more easily than their distant c…
VLTI/GRAVITY Provides Evidence the Young, Substellar Companion HD 136164 Ab formed like a "Failed Star"
William O. Balmer, L. Pueyo, S. Lacour +93
Young, low-mass Brown Dwarfs orbiting early-type stars, with low mass ratios (), appear intrinsically rare and present a formation dilemma: could a handful of these…
Exploring the presence of a fifth force at the Galactic Center
The GRAVITY Collaboration, K. Abd El Dayem, R. Abuter +60
Aims: The presence of a Yukawa-like correction to Newtonian gravity is investigated at the Galactic Center, leading to a new upper limit for the intensity of such a correction. Met…
GRAVITY K-band spectroscopy of HD 206893 B: brown dwarf or exoplanet
J. Kammerer, S. Lacour, T. Stolker +94
We aim to reveal the nature of the reddest known substellar companion HD 206893 B by studying its near-infrared colors and spectral morphology and by investigating its orbital moti…
The interferometric baselines and GRAVITY astrometric error budget
S. Lacour, F. Eisenhauer, S. Gillessen +9
GRAVITY is a new generation beam combination instrument for the VLTI. Its goal is to achieve microarsecond astrometric accuracy between objects separated by a few arcsec. This $10^…
Dynamically important magnetic fields near the event horizon of Sgr A*
GRAVITY Collaboration, A. Jiménez-Rosales, J. Dexter +53
We study the time-variable linear polarisation of Sgr A* during a bright NIR flare observed with the GRAVITY instrument on July 28, 2018. Motivated by the time evolution of both th…
Polarization analysis of the VLTI and GRAVITY
GRAVITY Collaboration, F. Widmann, X. Haubois N. Schuhler +59
The goal of this work is to characterize the polarization effects of the VLTI and GRAVITY. This is needed to calibrate polarimetric observations with GRAVITY for instrumental effec…
The ExoGRAVITY project: using single mode interferometry to characterize exoplanets
S. Lacour, J. J. Wang, M. Nowak +89
Combining adaptive optics and interferometric observations results in a considerable contrast gain compared to single-telescope, extreme AO systems. Taking advantage of this, the E…
First Light for the GRAVITY+ Adaptive Optics: Extreme Adaptive Optics for the Very Large Telescope Interferometer
GRAVITY+ Collaboration, :, F. Allouche +137
GRAVITY+ improves by orders of magnitude the sensitivity, sky-coverage and contrast of the Very Large Telescope Interferometer (VLTI). A central part of this project is the develop…
Modeling the orbital motion of Sgr A*'s near-infrared flares
The GRAVITY Collaboration, M. Bauböck, J. Dexter +53
Infrared observations of Sgr A* probe the region close to the event horizon of the black hole at the Galactic center. These observations can constrain the properties of low-luminos…
The GRAVITY Young Stellar Object survey -- I. Probing the disks of Herbig Ae/Be stars in terrestrial orbits
K. Perraut, L. Labadie, B. Lazareff +69
The formation and the evolution of protoplanetary disks are important stages in the lifetime of stars. The processes of disk evolution and planet formation are intrinsically linked…