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1. The GRAVITY Young Stellar Object survey -- I. Probing the disks of Herbig Ae/Be stars in terrestrial orbits

Author: Perraut, K., Labadie, L., Lazareff, B., Klarmann, L., Segura-Cox, D., Benisty, M., Bouvier, J., Brandner, W., Garatti, A. Caratti o, Caselli, P., Dougados, C., Garcia, P., Garcia-Lopez, R., Kendrew, S., Koutoulaki, M., Kervella, P., Lin, C. -C., Pineda, J., Sanchez-Bermudez, J., van Dishoeck, E., Abuter, R., Amorim, A., Berger, J. -P., Bonnet, H., Buron, A., Cantalloube, F., Clénet, Y., Foresto, V. Coudé du, Dexter, J., de Zeeuw, P. T., Duvert, G., Eckart, A., Eisenhauer, F., Eupen, F., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Gordo, P., Grellmann, R., Haubois, X., Haussmann, F., Henning, T., Hippler, S., Horrobin, M., Hubert, Z., Jocou, L., Lacour, S., Bouquin, J. -B. Le, Léna, P., Mérand, A., Ott, T., Paumard, T., Perrin, G., Pfuhl, O., Rabien, S., Ray, T., Rau, C., Rousset, G., Scheithauer, S., Straub, O., Straubmeier, C., Sturm, E., Vincent, F., Waisberg, I., Wank, I., Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Woillez, J., and Yazici, S.
Subjects: Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract: 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. We spatially resolve with GRAVITY/VLTI in the K-band the sub au-scale region of 27 stars to gain statistical understanding of their properties. We look for correlations with stellar parameters, such as luminosity, mass, temperature and age. Our sample also cover a range of various properties in terms of reprocessed flux, flared or flat morphology, and gaps. We developed semi-physical geometrical models to fit our interferometric data. Our best models correspond to smooth and wide rings, implying that wedge-shaped rims at the dust sublimation edge are favored, as found in the H-band. The closure phases are generally non-null with a median value of ~10 deg, indicating spatial asymmetries of the intensity distributions. Multi-size grain populations could explain the closure phase ranges below 20-25 deg but other scenarios should be invoked to explain the largest ones. Our measurements extend the Radius-Luminosity relation to ~1e4 Lsun and confirm the significant spread around the mean relation observed in the H-band. Gapped sources exhibit a large N-to-K band size ratio and large values of this ratio are only observed for the members of our sample that would be older than 1 Ma, less massive, and with lower luminosity. In the 2 Ms mass range, we observe a correlation in the increase of the relative age with the transition from group II to group I, and an increase of the N-to-K size ratio. However, the size of the current sample does not yet permit us to invoke a clear universal evolution mechanism across the HAeBe mass range. The measured locations of the K-band emission suggest that these disks might be structured by forming young planets, rather than by depletion due to EUV, FUV, and X-ray photo-evaporation., Comment: Accepted for publication in A&A; 23 pages, 16 figures, 7 tables
Published: 2019
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2. First direct detection of an exoplanet by optical interferometry; Astrometry and K-band spectroscopy of HR8799 e

Author: Lacour, S., Nowak, M., Wang, J., Pfuhl, O., Eisenhauer, F., Abuter, R., Amorim, A., Anugu, N., Benisty, M., Berger, J. P., Beust, H., Blind, N., Bonnefoy, M., Bonnet, H., Bourget, P., Brandner, W., Buron, A., Collin, C., Charnay, B., Chapron, F., Clénet, Y., Foresto, V. Coudé du, de Zeeuw, P. T., Deen, C., Dembet, R., Dexter, J., Duvert, G., Eckart, A., Schreiber, N. M. Förster, Fédou, P., Garcia, P., Lopez, R. Garcia, Gao, F., Gendron, E., Genzel, R., Gillessen, S., Gordo, P., Greenbaum, A., Habibi, M., Haubois, X., Haußmann, F., Henning, Th., Hippler, S., Horrobin, M., Hubert, Z., Rosales, A. Jimenez, Jocou, L., Kendrew, S., Kervella, P., Kolb, J., Lagrange, A. -M., Lapeyrère, V., Bouquin, J. -B. Le, Léna, P., Lippa, M., Lenzen, R., Maire, A. -L., Mollière, P., Ott, T., Paumard, T., Perraut, K., Perrin, G., Pueyo, L., Rabien, S., Ramirez, A., Rau, C., Rodriguez-Coira, G., Rousset, G., Sanchez-Bermudez, J., Scheithauer, S., Schuhler, N., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., Vincent, F., van Dishoeck, E. F., von Fellenberg, S., Wank, I., Waisberg, I., Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Woillez, J., Yazici, S., Ziegler, D., and Zins, G.
Subjects: Astrophysics - Earth and Planetary Astrophysics
Abstract: 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 of high contrast observations, enabling the direct observation of exoplanets. We demonstrate the technique on HR8799, a young planetary system composed of four known giant exoplanets. We used the GRAVITY fringe tracker to lock the fringes on the central star, and integrated off-axis on the HR8799e planet situated at 390 mas from the star. Data reduction included post-processing to remove the flux leaking from the central star and to extract the coherent flux of the planet. The inferred K band spectrum of the planet has a spectral resolution of 500. We also derive the astrometric position of the planet relative to the star with a precision on the order of 100$\,\mu$as. The GRAVITY astrometric measurement disfavors perfectly coplanar stable orbital solutions. A small adjustment of a few degrees to the orbital inclination of HR 8799 e can resolve the tension, implying that the orbits are close to, but not strictly coplanar. The spectrum, with a signal-to-noise ratio of $\approx 5$ per spectral channel, is compatible with a late-type L brown dwarf. Using Exo-REM synthetic spectra, we derive a temperature of $1150\pm50$\,K and a surface gravity of $10^{4.3\pm0.3}\,$cm/s$^{2}$. This corresponds to a radius of $1.17^{+0.13}_{-0.11}\,R_{\rm Jup}$ and a mass of $10^{+7}_{-4}\,M_{\rm Jup}$, which is an independent confirmation of mass estimates from evolutionary models. Our results demonstrate the power of interferometry for the direct detection and spectroscopic study of exoplanets at close angular separations from their stars., Comment: published in A&A
Published: 2019
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3. GRAVITY chromatic imaging of Eta Car's core

Author: GRAVITY Collaboration, Sanchez-Bermudez, J., Weigelt, G., Bestenlehner, J. M., Kervella, P., Brandner, W., Henning, Th., Müller, A., Perrin, G., Pott, J. -U., Schöller, M., van Boekel, R., Abuter, R., Accardo, M., Amorim, A., Anugu, N., Ávila, G., Benisty, M., Berger, J. P., Blind, N., Bonnet, H., Bourget, P., Brast, R., Buron, A., Cantalloube, F., Garatti, A. Caratti o, Cassaing, F., Chapron, F., Choquet, E., Clénet, Y., Collin, C., Foresto, V. Coudé du, de Wit, W., de Zeeuw, T., Deen, C., Delplancke-Ströbele, F., Dembet, R., Derie, F., Dexter, J., Duvert, G., Ebert, M., Eckart, A., Eisenhauer, F., Esselborn, M., Fédou, P., Garcia, P. J. V., Dabo, C. E. Garcia, Lopez, R. Garcia, Gao, F., Gendron, E., Genzel, R., Gillessen, S., Haubois, X., Haug, M., Haussmann, F., Hippler, S., Horrobin, M., Huber, A., Hubert, Z., Hubin, N., Hummel, C. A., Jakob, G., Jochum, L., Jocou, L., Karl, M., Kaufer, A., Kellner, S., Kendrew, S., Kern, L., Kiekebusch, M., Klein, R., Kolb, J., Kulas, M., Lacour, S., Lapeyrère, V., Lazareff, B., Bouquin, J. -B. Le, Léna, P., Lenzen, R., Levêque, S., Lippa, M., Magnard, Y., Mehrgan, L., Mellein, M., Mérand, A., Moreno-Ventas, J., Moulin, T., Müller, E., Müller, F., Neumann, U., Oberti, S., Ott, T., Pallanca, L., Panduro, J., Pasquini, L., Paumard, T., Percheron, I., Perraut, K., Petrucci, P. -O., Pflüger, A., Pfuhl, O., Duc, T. P., Plewa, P. M., Popovic, D., Rabien, S., Ramirez, A., Ramos, J., Rau, C., Riquelme, M., Rodríguez-Coira, G., Rohloff, R. -R., Rosales, A., Rousset, G., Scheithauer, S., Schuhler, N., Spyromilio, J., Straub, O., Straubmeier, C., Sturm, E., Suarez, M., Tristram, K. R. W., Ventura, N., Vincent, F., Waisberg, I., Wank, I., Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Wittkowski, M., Woillez, J., Wolff, B., Yazici, S., Ziegler, D., and Zins, G.
Subjects: Astrophysics - Solar and Stellar Astrophysics
Abstract: 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 residing in its core. 2D and 3D radiative transfer and hydrodynamic simulations predict a primary with a dense and slow stellar wind that interacts with the faster and lower density wind of the secondary. The wind-wind collision scenario suggests that the secondary's wind penetrates the primary's wind creating a low-density cavity in it, with dense walls where the two winds interact. We aim to trace the inner ~5-50 au structure of Eta Car's wind-wind interaction, as seen through BrG and, for the first time, through the He I 2s-2p line. We have used spectro-interferometric observations with GRAVITY at the VLTI. Our modeling of the continuum allows us to estimate its FWHM angular size close to 2 mas and an elongation ratio of 1.06 +/- 0.05 over a PA = 130 +/- 20 deg. Our CMFGEN modeling helped us to confirm that the role of the secondary should be taken into account to properly reproduce the observed BrG and He I lines. Chromatic images across BrG reveal a southeast arc-like feature, possibly associated to the hot post-shocked winds flowing along the cavity wall. The images of He I 2s-2p served to constrain the 20 mas structure of the line-emitting region. The observed morphology of He I suggests that the secondary is responsible for the ionized material that produces the line profile. Both the BrG and the He I 2s-2p maps are consistent with previous hydrodynamical models of the colliding wind scenario. Future dedicated simulations together with an extensive interferometric campaign are necessary to refine our constraints on the wind and stellar parameters of the binary, which finally will help us predict the evolutionary path of Eta Car., Comment: 32 pages, 27 figures (14 in the main body, 13 in the appendices), accepted for publication in AA
Published: 2018
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4. Detection of the gravitational redshift in the orbit of the star S2 near the Galactic centre massive black hole

Author: GRAVITY Collaboration, Abuter, R., Amorim, A., Anugu, N., Bauböck, M., Benisty, M., Berger, J. P., Blind, N., Bonnet, H., Brandner, W., Buron, A., Collin, C., Chapron, F., Clénet, Y., Foresto, V. Coudé du, de Zeeuw, P. T., Deen, C., Delplancke-Ströbele, F., Dembet, R., Dexter, J., Duvert, G., Eckart, A., Eisenhauer, F., Finger, G., Schreiber, N. M. Förster, Fédou, P., Garcia, P., Lopez, R. Garcia, Gao, F., Gendron, E., Genzel, R., Gillessen, S., Gordo, P., Habibi, M., Haubois, X., Haug, M., Haußmann, F., Henning, Th., Hippler, S., Horrobin, M., Hubert, Z., Hubin, N., Rosales, A. Jimenez, Jochum, L., Jocou, L., Kaufer, A., Kellner, S., Kendrew, S., Kervella, P., Kok, Y., Kulas, M., Lacour, S., Lapeyrère, V., Lazareff, B., Bouquin, J. -B. Le, Léna, P., Lippa, M., Lenzen, R., Mérand, A., Müller, E., Neumann, U., Ott, T., Palanca, L., Paumard, T., Pasquini, L., Perraut, K., Perrin, G., Pfuhl, O., Plewa, P. M., Rabien, S., Ramírez, A., Ramos, J., Rau, C., Rodríguez-Coira, G., Rohloff, R. -R., Rousset, G., Sanchez-Bermudez, J., Scheithauer, S., Schöller, M., Schuler, N., Spyromilio, J., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., Tristram, K. R. W., Vincent, F., von Fellenberg, S., Wank, I., Waisberg, I., Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Woillez, J., Yazici, S., Ziegler, D., and Zins, G.
Subjects: Astrophysics - Astrophysics of Galaxies, General Relativity and Quantum Cosmology, Physics - Classical Physics
Abstract: 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. Near pericentre at 120 AU, ~1400 Schwarzschild radii, the star has an orbital speed of ~7650 km/s, such that the first-order effects of Special and General Relativity have now become detectable with current capabilities. Over the past 26 years, we have monitored the radial velocity and motion on the sky of S2, mainly with the SINFONI and NACO adaptive optics instruments on the ESO Very Large Telescope, and since 2016 and leading up to the pericentre approach in May 2018, with the four-telescope interferometric beam-combiner instrument GRAVITY. From data up to and including pericentre, we robustly detect the combined gravitational redshift and relativistic transverse Doppler effect for S2 of z ~ 200 km/s / c with different statistical analysis methods. When parameterising the post-Newtonian contribution from these effects by a factor f, with f = 0 and f = 1 corresponding to the Newtonian and general relativistic limits, respectively, we find from posterior fitting with different weighting schemes f = 0.90 +/- 0.09 (stat) +\- 0.15 (sys). The S2 data are inconsistent with pure Newtonian dynamics., Comment: Accepted for publication in A&A Letters, 29 June 2018, 10 pages, 6 figures, corresponding author: F. Eisenhauer
Published: 2018
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5. The wind and the magnetospheric accretion onto the T Tauri star S Coronae Australis at sub-au resolution

Author: Lopez, R. Garcia, Perraut, K., Garatti, A. Caratti o, Lazareff, B., Sanchez-Bermudez, J., Benisty, M., Dougados, C., Labadie, L., Brandner, W., Garcia, P. J. V., Henning, Th., Ray, T. P., Abuter, R., Amorim, A., Anugu, N., Berger, J. P., Bonnet, H., Buron, A., Caselli, P., Clénet, Y., Foresto, V. Coudé du, de Wit, W., Deen, C., Delplancke-Ströbele, F., Dexter, J., Eckart, A., Eisenhauer, F., Dabo, C. E. Garcia, Gendron, E., Genzel, R., Gillessen, S., Haubois, X., Haug, M., Haussmann, F., Hippler, S., Hubert, Z., Hummel, C. A., Horrobin, M., Jocou, L., Kellner, S., Kervella, P., Kulas, M., Kolb, J., Lacour, S., Bouquin, J. -B. Le, Léna, P., Lippa, M, Mérand, A., Müller, E., Ott, T., Panduro, J., Paumard, T., Perrin, G., Pfuhl, O., Ramirez, A., Rau, C., Rohloff, R. -R., Rousset, G., Scheithauer, S., Schöller, M., Straubmeier, C., Sturm, E., Thi, W. F., van Dishoeck, E., Vincent, F., Waisberg, I., Wank, I., Wieprecht, E., Wiest, M., Wiezorrek, E., Woillez, J., Yazici, S., and Zins, G.
Subjects: Astrophysics - Solar and Stellar Astrophysics
Abstract: 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 VLTI-GRAVITY high spectral resolution ($R\sim$4000) observations of a classical TTauri binary, S CrA (composed of S CrA N and S CrA S and separated by $\sim$1.4"), combining the four 8-m telescopes in dual-field mode. Our observations in the near-infrared K-band continuum reveal a disk around each binary component, with similar half-flux radii of about 0.1 au at d$\sim$130 pc, inclinations ($i=$28$\pm$3$^o$\ and $i=$22$\pm$6$^o$), and position angles (PA=0$^o\pm$6$^o$ and PA=-2$^o\pm$12$^o$), suggesting that they formed from the fragmentation of a common disk. The S CrA N spectrum shows bright HeI and Br$\gamma$ line emission exhibiting inverse P-Cygni profiles, typically associated with infalling gas. The continuum-compensated Br$\gamma$ line visibilities of S CrA N show the presence of a compact Br$\gamma$ emitting region the radius of which is about $\sim$0.06 au, which is twice as big as the truncation radius. This component is mostly tracing a wind. Moreover, a slight radius change between the blue- and red-shifted Br$\gamma$ line components is marginally detected. The presence of an inverse P-Cygni profile in the HeI and Br$\gamma$ lines, along with the tentative detection of a slightly larger size of the blue-shifted Br$\gamma$ line component, hint at the simultaneous presence of a wind and magnetospheric accretion in S CrA N., Comment: Accepted by A&A
Published: 2017
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6. Accretion-ejection morphology of the microquasar SS433 resolved at sub-au scale

Author: GRAVITY Collaboration, Petrucci, P. -O., Waisberg, I., Bouquin, J. -B. Le, Dexter, J., Dubus, G., Perraut, K., Kervella, P., Abuter, R., Amorim, A., Anugu, N., Berger, J. P., Blind, N., Bonnet, H., Brandner, W., Buron, A., Choquet, É., Clénet, Y., de Wit, W., Deen, C., Eckart, A., Eisenhauer, F., Finger, G., Garcia, P., Lopez, R. Garcia, Gendron, E., Genzel, R., Gillessen, S., Gonte, F., Haubois, X., Haug, M., Haussmann, F., Henning, Th., Hippler, S., Horrobin, M., Hubert, Z., Jochum, L., Jocou, L., Kok, Y., Kolb, J., Kulas, M., Lacour, S., Lazareff, B., Lèna, P., Lippa, M., Mérand, A., Müller, E., Ott, T., Panduro, J., Paumard, T., Perrin, G., Pfuhl, O., Ramos, J., Rau, C., Rohloff, R. -R., Rousset, G., Sanchez-Bermudez, J., Scheithauer, S., Schöller, M., Straubmeier, C., Sturm, E., Vincent, F., Wank, I., Wieprecht, E., Wiest, M., Wiezorrek, E., Wittkowski, M., Woillez, J., Yazici, S., and Zins, G.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Solar and Stellar Astrophysics
Abstract: 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 exposure reveals a rich K-band spectrum dominated by hydrogen Br$\gamma\ $ and \ion{He}{i} lines, as well as (red-shifted) emission lines coming from the jets. The K-band continuum emitting region is dominated by a marginally resolved point source ($<$ 1 mas) embedded inside a diffuse background accounting for 10\% of the total flux. The jet line positions agree well with the ones expected from the jet kinematic model, an interpretation also supported by the consistent sign (i.e. negative/positive for the receding/approaching jet component) of the phase shifts observed in the lines. The significant visibility drop across the jet lines, together with the small and nearly identical phases for all baselines, point toward a jet that is offset by less than 0.5 mas from the continuum source and resolved in the direction of propagation, with a typical size of 2 mas. The jet position angle of $\sim$80$^{\circ}$ is consistent with the expected one at the observation date. Jet emission so close to the central binary system would suggest that line locking, if relevant to explain the amplitude and stability of the 0.26c jet velocity, operates on elements heavier than hydrogen. The Br$\gamma\ $ profile is broad and double peaked. It is better resolved than the continuum and the change of the phase signal sign across the line on all baselines suggests an East-West oriented geometry alike the jet direction and supporting a (polar) disk wind origin., Comment: Submitted for publication in A&A Letters, 4 pages + appendix, 4 figures. Comments welcome
Published: 2017
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7. Sub-milliarcsecond Optical Interferometry of the HMXB BP Cru with VLTI/GRAVITY

Author: GRAVITY Collaboration, Waisberg, I., Dexter, J., Pfuhl, O., Abuter, R., Amorin, A., Anugu, N., Berger, J. P., Blind, N., Bonnet, H., Brandner, W., Buron, A., Clénet, Y., de Wit, W., Deen, C., Delplancke-Ströbele, F., Dembet, R., Duvert, G., Eckart, A., Eisenhauer, F., Fédou, P., Finger, G., Garcia, P., Lopez, R. Garcia, Gendron, E., Genzel, R., Gillessen, S., Haubois, X., Haug, M., Haussmann, F., Henning, Th., Hippler, S., Horrobin, M., Hubert, Z., Jochum, L., Jocou, L., Kervella, P., Kok, Y., Kulas, M., Lacour, S., Lapeyrère, V., Bouquin, J. -B. Le, Lèna, P., Lippa, M., Mérand, A., Müller, E., Ott, T., Pallanca, L., Panduro, J., Paumard, T., Perraut, K., Perrin, G., Rabien, S., Ramírez, A., Ramos, J., Rau, C., Rohloff, R. -R., Rousset, G., Sanchez-Bermudez, J., Scheithauer, S., Schöller, M., Straubmeier, C., Sturm, E., Vincent, F., Wank, I., Wieprecht, E., Wiest, M., Wiezorrek, E., Wittkowski, M., Woillez, J., and Yazici, S.
Subjects: Astrophysics - Solar and Stellar Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract: 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 size of the hypergiant. Differential visibility amplitude ($\Delta |V| \sim 5\%$) and phase ($\Delta \phi \sim 2 \deg$) signatures are observed across the HeI $2.059 \mu$m and Br$\gamma$ lines, the latter seen strongly in emission, unusual for the donor star's spectral type. For a baseline $B \sim 100$m, the differential phase RMS $\sim 0.2 \deg$ corresponds to an astrometric precision of $\sim 2 \mu$as. A model-independent analysis in the marginally resolved limit of interferometry reveals asymmetric and extended emission with a strong wavelength dependence. We propose geometric models based on an extended and distorted wind and/or a high density gas stream, which has long been predicted to be present in this system. The observations show that optical interferometry is now able to resolve HMXBs at the spatial scale at which accretion takes place, and therefore probe the effects of the gravitational and radiation fields of the compact object on its environment., Comment: Submitted to ApJ, 22 pages, 17 figures
Published: 2017
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8. First Light for GRAVITY: Phase Referencing Optical Interferometry for the Very Large Telescope Interferometer

Author: GRAVITY Collaboration, Abuter, R., Accardo, M., Amorim, A., Anugu, N., Ávila, G., Azouaoui, N., Benisty, M., Berger, J. P., Blind, N., Bonnet, H., Bourget, P., Brandner, W., Brast, R., Buron, A., Burtscher, L., Cassaing, F., Chapron, F., Choquet, É., Clénet, Y., Collin, C., Foresto, V. Coudé du, de Wit, W., de Zeeuw, P. T., Deen, C., Delplancke-Ströbele, F., Dembet, R., Derie, F., Dexter, J., Duvert, G., Ebert, M., Eckart, A., Eisenhauer, F., Esselborn, M., Fédou, P., Finger, G., Garcia, P., Dabo, C. E. Garcia, Lopez, R. Garcia, Gendron, E., Genzel, R., Gillessen, S., Gonte, F., Gordo, P., Grould, M., Grözinger, U., Guieu, S., Haguenauer, P., Hans, O., Haubois, X., Haug, M., Haussmann, F., Henning, Th., Hippler, S., Horrobin, M., Huber, A., Hubert, Z., Hubin, N., Hummel, C. A., Jakob, G., Janssen, A., Jochum, L., Jocou, L., Kaufer, A., Kellner, S., Kern, L., Kervella, P., Kiekebusch, M., Klein, R., Kok, Y., Kolb, J., Kulas, M., Lacour, S., Lapeyrère, V., Lazareff, B., Bouquin, J. -B. Le, Lèna, P., Lenzen, R., Lévêque, S., Lippa, M., Magnard, Y., Mehrgan, L., Mellein, M., Mérand, A., Moreno-Ventas, J., Moulin, T., Müller, E., Müller, F., Neumann, U., Oberti, S., Ott, T., Pallanca, L., Panduro, J., Pasquini, L., Paumard, T., Percheron, I., Perraut, K., Perrin, G., Pflüger, A., Pfuhl, O., Duc, T. Phan, Plewa, P. M., Popovic, D., Rabien, S., Ramírez, A., Ramos, J., Rau, C., Riquelme, M., Rohloff, R. -R., Rousset, G., Sanchez-Bermudez, J., Scheithauer, S., Schöller, M., Schuhler, N., Spyromilio, J., Straubmeier, C., Sturm, E., Suarez, M., Tristram, K. R. W., Ventura, N., Vincent, F., Waisberg, I., Wank, I., Weber, J., Wieprecht, E., Wiest, M., Wiezorrek, E., Wittkowski, M., Woillez, J., Wolff, B., Yazici, S., Ziegler, D., and Zins, G.
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: 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 diameter angular resolution and a collecting area of 200 m$^2$. The instrument comprises fiber fed integrated optics beam combination, high resolution spectroscopy, built-in beam analysis and control, near-infrared wavefront sensing, phase-tracking, dual beam operation and laser metrology [...]. This article gives an overview of GRAVITY and reports on the performance and the first astronomical observations during commissioning in 2015/16. We demonstrate phase tracking on stars as faint as m$_K$ ~ 10 mag, phase-referenced interferometry of objects fainter than m$_K$ ~ 15 mag with a limiting magnitude of m$_K$ ~ 17 mag, minute long coherent integrations, a visibility accuracy of better than 0.25 %, and spectro-differential phase and closure phase accuracy better than 0.5{\deg}, corresponding to a differential astrometric precision of better than 10 microarcseconds ({\mu}as). The dual-beam astrometry, measuring the phase difference of two objects with laser metrology, is still under commissioning. First observations show residuals as low as 50 {\mu}as when following objects over several months. We illustrate the instrument performance with the observations of archetypical objects for the different instrument modes. Examples include the Galactic Center supermassive black hole and its fast orbiting star S2 for phase referenced dual beam observations and infrared wavefront sensing, the High Mass X-Ray Binary BP Cru and the Active Galactic Nucleus of PDS 456 for few {\mu}as spectro-differential astrometry, the T Tauri star S CrA for a spectro-differential visibility analysis, {\xi} Tel and 24 Cap for high accuracy visibility observations, and {\eta} Car for interferometric imaging with GRAVITY., Comment: Accepted for publication in A&A, 23 pages, 23 figures, corresponding author: F. Eisenhauer
Published: 2017
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9. Beating the confusion limit: The necessity of high angular resolution for probing the physics of Sagittarius A* and its environment: Opportunities for LINC-NIRVANA (LBT), GRAVITY (VLTI) and and METIS (E-ELT)

Author: Eckart, A., Sabha, N., Witzel, G., Straubmeier, C., Shahzamanian, B., Valencia-S., M., Garcia-Marin, M., Horrobin, M., Moser, L., Zuther, J., Fischer, S., Rauch, C., Rost, S., Iserlohe, C., Yazici, S., Smajic, S., Wiest, M., Araujo-Hauck, C., and Wank, I.
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract: The super-massive 4 million solar mass black hole (SMBH) SgrA* shows variable emission from the millimeter to the X-ray domain. A detailed analysis of the infrared light curves allows us to address the accretion phenomenon in a statistical way. The analysis shows that the near-infrared flux density excursions are dominated by a single state power law, with the low states of SgrA* limited by confusion through the unresolved stellar background. We show that for 8-10m class telescopes blending effects along the line of sight will result in artificial compact star-like objects of 0.5-1 mJy that last for about 3-4 years. We discuss how the imaging capabilities of GRAVITY at the VLTI, LINC-NIRVANA at the LBT and METIS at the E-ELT will contribute to the investigation of the low variability states of SgrA*., Comment: 19 pages, 5 figure, Conf. Proc. SPIE Astronomical Telescopes + Instrumentation 1 - 6 July 2012. Amsterdam No. 8445-4
Published: 2012
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10. A consensus protocol for functional connectivity analysis in the rat brain

Author: Grandjean, J., Desrosiers-Gregoire, G., Anckaerts, C., Angeles-Valdez, D., Ayad, F., Barrière, D., Blockx, I., Bortel, A., Broadwater, M., Cardoso, B., Célestine, M., Chavez-Negrete, J., Choi, S., Christiaen, E., Clavijo, P., Colon-Perez, L., Cramer, S., Daniele, T., Dempsey, E., Diao, Y., Doelemeyer, A., Dopfel, D., Dvořáková, L., Falfán-Melgoza, C., Fernandes, F., Fowler, C., Fuentes-Ibañez, A., Garin, C., Gelderman, E., Golden, C., Guo, C., Henckens, M., Hennessy, L., Herman , P., Hofwijks, N., Horien, C., Ionescu, T., Jones, J., Kaesser, J., Kim, E., Lambers, H., Lazari, A., Lee, S., Lillywhite, A., Liu, Y., López-Castro, A., López-Gil , X., Ma, Z., MacNicol, E., Madularu, D., Mandino, F., Marciano, S., McAuslan, M., McCunn, P., McIntosh, A., Meng, X., Meyer-Baese, L., Missault, S., Moro, F., Naessens, D., Nava-Gomez, L., Nonaka, H., Ortiz, J., Paasonen, J., Pais-Roldán, P., Peeters, L., Pereira, M., Perez, P., Pompilus, M., Prior, M., Rakhmatullin, R., Reimann, H., Reinwald, J., Triana Del Rio, R., Rivera-Olvera, A., Ruiz-Pérez, D., Russo, G., Rutten, T., Ryoke, R., Sack, M., Salvan, P., Sanganahalli, B., Schroeter, A., Seewoo , B., Selingue, E., Seuwen, A., Shi, B., Sirmpilatze, N., Smith, J., Smith, C., Sobczak, F., Stenroos, P., Straathof, M., Strobelt, S., Sumiyoshi, A., Takahashi, K., Torres-García, M., Tudela, R., van den Berg, M., van der Marel, K., van Hout, A., Vertullo, R., Vidal, B., Vrooman, R., Wang, X., Wank, I., Watson, D., Yin, T., Zhang, Y., Zurbruegg, S., Achard, S., Alcauter, S., Auer, D., Barbier, E., Baudewig, J., Beckmann, C., Beckmann, N., Becq, G., Blezer, E., Bolbos, R., Boretius, S., Bouvard, S., Budinger, E., Buxbaum, J., Cash, D., Chapman, V., Chuang, K., Ciobanu, L., Coolen, B., Dalley, J., Dhenain, M., Dijkhuizen, R., Esteban, O., Faber, C., Febo, M., Feindel, K., Forloni, G., Fouquet, J., Garza-Villarreal, E., Gass, N., Glennon, J., Gozzi, A., Gröhn, O., Harkin, A., Heerschap, A., Helluy, X., Herfert , K., Heuser, A., Homberg, J., Houwing, D., Hyder, F., Ielacqua, G., Jelescu, I., Johansen-Berg, H., Kaneko, G., Kawashima, R., Keilholz, S., Keliris, G., Kelly, C., Kerskens, C., Khokhar, J., Kind, P., Langlois, J., Lerch, J., López-Hidalgo, M., Manahan-Vaughan, D., Marchand, F., Mars, R., Marsella, G., Micotti , E., Muñoz-Moreno , E., Near, J., Niendorf, T., Otte, W., Pan , W., Prado-Alcalá, R., Quirarte, G., Rodger , J., Rosenow, T., Sampaio-Baptista, C., Sartorius, A., Sawiak, S., Scheenen, T., Shemesh, Shih, Y., Shmuel, A., Soria, G., Stoop, R., Thompson, G., Till, S., Todd, N., Van Der Linden, A., van der Toorn, A., van Tilborg, G., Vanhove, C., Veltien, A., Verhoye, M., Wachsmuth, L., Weber-Fahr, W., Wenk , P., Yu, X., Zerbi , V., Zhang , N., Zhang, B., Zimmer, L., Devenyi, G., Chakravarty, M., and Hess, A.
Subjects: Action, intention, and motor control, General Neuroscience, fmri, Medizin, Stress-related disorders Donders Center for Medical Neuroscience [Radboudumc 13], Human medicine
Abstract: Task-free functional connectivity in animal models provides an experimental framework to examine connectivity phenomena under controlled conditions and allows for comparisons with data modalities collected under invasive or terminal procedures. Currently, animal acquisitions are performed with varying protocols and analyses that hamper result comparison and integration. Here we introduce StandardRat, a consensus rat functional magnetic resonance imaging acquisition protocol tested across 20 centers. To develop this protocol with optimized acquisition and processing parameters, we initially aggregated 65 functional imaging datasets acquired from rats across 46 centers. We developed a reproducible pipeline for analyzing rat data acquired with diverse protocols and determined experimental and processing parameters associated with the robust detection of functional connectivity across centers. We show that the standardized protocol enhances biologically plausible functional connectivity patterns relative to previous acquisitions. The protocol and processing pipeline described here is openly shared with the neuroimaging community to promote interoperability and cooperation toward tackling the most important challenges in neuroscience. The authors pooled resources to identify best practices and develop a new standardized protocol for estimating functional connectivity in rats with magnetic resonance imaging.
Published: 2023
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11. Author Correction: A consensus protocol for functional connectivity analysis in the rat brain

Author: Grandjean, J., Desrosiers-Gregoire, G., Anckaerts, C., Angeles-Valdez, D., Ayad, F., Barrière, D., Blockx, I., Bortel, A., Broadwater, M., Cardoso, B., Célestine, M., Chavez-Negrete, J., Choi, S., https://orcid.org/0000-0001-7327-1344, Christiaen, E., Clavijo, P., Colon-Perez, L., Cramer, S., Daniele, T., Dempsey, E., Diao, Y., Doelemeyer, A., Dopfel, D., Dvořáková, L., Falfán-Melgoza, C., Fernandes, F., Fowler, C., Fuentes-Ibañez, A., Garin, C., Gelderman, E., Golden, C., Guo, C., Henckens, M., Hennessy, L., Herman , P., Hofwijks, N., Horien, C., Ionescu, T., Jones, J., Kaesser, J., Kim, E., Lambers, H., Lazari, A., Lee, S., Lillywhite, A., Liu, Y., López-Castro, A., López-Gil , X., Ma, Z., MacNicol, E., Madularu, D., Mandino, F., Marciano, S., McAuslan, M., McCunn, P., McIntosh, A., Meng, X., Meyer-Baese, L., Missault, S., Moro, F., Naessens, D., Nava-Gomez, L., Nonaka, H., Ortiz, J., Paasonen, J., Pais-Roldán, P., https://orcid.org/0000-0002-9381-3048, Peeters, L., Pereira, M., Perez, P., Pompilus, M., Prior, M., Rakhmatullin, R., Reimann, H., Reinwald, J., Triana Del Rio, R., Rivera-Olvera, A., Ruiz-Pérez, D., Russo, G., Rutten, T., Ryoke, R., Sack, M., Salvan, P., Sanganahalli, B., Schroeter, A., Seewoo , B., Selingue, E., Seuwen, A., Shi, B., Sirmpilatze, N., Smith, J., Smith, C., Sobczak, F., Stenroos, P., Straathof, M., Strobelt, S., Sumiyoshi, A., Takahashi, K., Torres-García, M., Tudela, R., van den Berg, M., van der Marel, K., van Hout, A., Vertullo, R., Vidal, B., Vrooman, R., Wang, X., Wank, I., Watson, D., Yin, T., Zhang, Y., Zurbruegg, S., Achard, S., Alcauter, S., Auer, D., Barbier, E., Baudewig, J., Beckmann, C., Beckmann, N., Becq, G., Blezer, E., Bolbos, R., Boretius, S., Bouvard, S., Budinger, E., Buxbaum, J., Cash, D., Chapman, V., Chuang, K., Ciobanu, L., Coolen, B., Dalley, J., Dhenain, M., Dijkhuizen, R., Esteban, O., Faber, C., Febo, M., Feindel, K., Forloni, G., Fouquet, J., Garza-Villarreal, E., Gass, N., Glennon, J., Gozzi, A., Gröhn, O., Harkin, A., Heerschap, A., Helluy, X., Herfert , K., Heuser, A., Homberg, J., Houwing, D., Hyder, F., Ielacqua, G., Jelescu, I., Johansen-Berg, H., Kaneko, G., Kawashima, R., Keilholz, S., Keliris, G., Kelly, C., Kerskens, C., Khokhar, J., Kind, P., Langlois, J., Lerch, J., López-Hidalgo, M., Manahan-Vaughan, D., Marchand, F., Mars, R., Marsella, G., Micotti , E., Muñoz-Moreno , E., Near, J., Niendorf, T., Otte, W., Pan , W., Prado-Alcalá, R., Quirarte, G., Rodger , J., Rosenow, T., Sampaio-Baptista, C., Sartorius, A., Sawiak, S., Scheenen, T., Shemesh, Shih, Y., Shmuel, A., https://orcid.org/0000-0003-3028-6639, Soria, G., Stoop, R., https://orcid.org/0000-0002-3532-1512, Thompson, G., Till, S., Todd, N., Van Der Linden, A., van der Toorn, A., van Tilborg, G., Vanhove, C., Veltien, A., Verhoye, M., Wachsmuth, L., Weber-Fahr, W., Wenk , P., Yu, X., Zerbi , V., Zhang , N., Zhang, B., Zimmer, L., Devenyi, G., Chakravarty, M., and Hess, A.
Subjects: General Neuroscience, Medizin
Abstract: Weitere Nicht-UDE Autoren sind nicht mit aufgeführt. in press
Published: 2023
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12. Hunting Exoplanets with Single-Mode Optical Interferometry

Author: Abuter, R., Accardo, M., Adler, T., Amorim, A., Anugu, N., Ávila, G., Bauböck, M., Benisty, M., Berger, J.-P., Bestenlehner, J. M., Beust, H., Blind, N., Bonnefoy, M., BONNET, H., Bourget, P., Bouvier, J., Brandner, W., Brast, R., Buron, A., Burtscher, L., Cantalloube, F., Caratti O Garatti, A., Caselli, P., Cassaing, F., Chapron, F., Charnay, B., Choquet, E., Clénet, Y., Collin, C., Coudé Du Foresto, V., Davies, R., Deen, C., Delplancke-Ströbele, F., Dembet, R., Derie, F., de Wit, W.-J., Dexter, J., De Zeeuw, T., Dougados, C., Dubus, G., Duvert, G., Ebert, M., Eckart, A., Eisenhauer, F., Esselborn, M., Eupen, F., Fédou, P., Ferreira, M. C., Finger, G., Förster Schreiber, N. M., Gao, F., García Dabó, C. E., Garcia Lopez, R., Garcia, P. J. V., Gendron, É., Genzel, R., Gerhard, O., Gil, J. P., Gillessen, S., Gonté, F., Gordo, P., Gratadour, D., Greenbaum, A., Grellmann, R., Grözinger, U., Guajardo, P., Guieu, S., Habibi, M., Haguenauer, P., Hans, O., Haubois, X., Haug, M., Haußmann, F., Henning, T., Hippler, S., Hönig, S. F., Horrobin, M., Huber, A., Hubert, Z., Hubin, N., Hummel, C. A., Jakob, G., Janssen, A., Jimenez Rosales, A., Jochum, L., Jocou, L., Kammerer, J., Karl, M., Kaufer, A., Kellner, S., Kendrew, S., Kern, L., Kervella, P., Kiekebusch, M., Kishimoto, M., Klarmann, L., Klein, R., Köhler, R., Kok, Y., Kolb, J., Koutoulaki, M., Kulas, M., Labadie, L., Lacour, S., Lagrange, A.-M., Lapeyrère, V., Laun, W., Lazareff, B., Le Bouquin, J.-B., Léna, P., Lenzen, R., Lévêque, S., Lin, C.-C., Lippa, M., Lutz, D., Magnard, Y., Maire, A.-L., Mehrgan, L., Mérand, A., Millour, F., Mollière, P., Moulin, T., Müller, A., Müller, E., Müller, F., Netzer, H., Neumann, U., Nowak, M., Oberti, S., Ott, T., Pallanca, L., Panduro, J., Pasquini, L., Paumard, T., Percheron, I., Perraut, K., Perrin, G., Peterson, B. M., Petrucci, P.-O., Pflüger, A., Pfuhl, O., Phan Duc, T., Pineda, J. E., Plewa, P. m., Popovic, D., Pott, J.-U., Prieto, A., Pueyo, L., Rabien, S., Ramírez, A., Ramos, J. R., Rau, C., Ray, T., Riquelme, M., Rodríguez-Coira, G., Rohloff, R.-R., Rouan, D., Rousset, G., Sanchez-Bermudez, J., Schartmann, M., Scheithauer, S., Schöller, M., Schuhler, N., Segura-Cox, D., Shangguan, J., Shimizu, T. T., Spyromilio, J., Sternberg, A., Stock, M. R., Straub, O., Straubmeier, C., Sturm, E., Suárez Valles, M., Tacconi, L. J., Thi, W.-F., Tristram, K. R. W., Valenzuela, J. J., Van Boekel, R., Van Dishoeck, E. F., Vermot, P., Vincent, F., Von fellenberg, S., Waisberg, I., Wang, J. J., Wank, I., Weber, J., Weigelt, G., Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Wittkowski, M., Woillez, J., Wolff, B., Yang, P., Yazici, S., Ziegler, D., Zins, G., and European Southern Observatory (ESO)
Subjects: [SDU]Sciences of the Universe [physics], Astrophysics::Instrumentation and Methods for Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: The GRAVITY instrument was primarily conceived for imaging and astrometry of the Galactic centre. However, its sensitivity and astrometric capabilities have also enabled interferometry to reach a new domain of astrophysics: exoplanetology. In March 2019, the GRAVITY collaboration published the first spectrum and astrometry of an exoplanet obtained by optical interferometry. In this article, we show how this observation is paving the way to even more exciting discoveries — finding new planets, and characterising their atmospheres., Published in The Messenger vol. 178, pp. 47-49, December 2019.
Published: 2019
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13. The GRAVITY Young Stellar Object survey

Author: Collaboration, Gravity, Perraut, K., Labadie, L., Lazareff, B., Klarmann, L., Segura-Cox, D., Benisty, M., Bouvier, J., Brandner, W., Caratti O Garatti, A., Caselli, P., Dougados, C., Garcia, P., Garcia-Lopez, R., Kendrew, S., Koutoulaki, M., Kervella, P., Lin, C.-C., Pineda, J., Sanchez-Bermudez, J., Van Dishoeck, E., Abuter, R., Amorim, A., Berger, J.-P., BONNET, H., Buron, A., Cantalloube, F., Clénet, Y., Coudé Du Foresto, V., Dexter, J., De Zeeuw, P. T., Duvert, G., Eckart, A., Eisenhauer, F., Eupen, F., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Gordo, P., Grellmann, R., Haubois, X., Haussmann, F., Henning, T., Hippler, S., Horrobin, M., Hubert, Z., Jocou, L., Lacour, S., Le Bouquin, J.-B., Léna, P., Mérand, A., Ott, T., Paumard, T., Perrin, G., Pfuhl, O., Rabien, S., Ray, T., Rau, C., Rousset, G., Scheithauer, S., Straub, O., Straubmeier, C., Sturm, E., Vincent, F., Waisberg, I., Wank, I., Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Woillez, J., Yazici, S., Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Max-Planck-Institut für Extraterrestrische Physik (MPE), LIttoral ENvironnement et Sociétés - UMR 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), National Tsing Hua University [Hsinchu] (NTHU), Laboratoire de Radiopathologie (LRP), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de la Santé et de la Recherche Médicale (INSERM), European Southern Observatory (ESO), Leiden Observatory [Leiden], Universiteit Leiden [Leiden], Institute Patology and Imunology Molecular, Fac Ciencias, Universidade do Porto [Porto], Département de Chimie Moléculaire (DCM), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Radioastronomie (MPIFR), Max Planck Institute for Extraterrestrial Physics (MPE), Physikalisches Institut [Köln], Universität zu Köln, Galaxies, Etoiles, Physique, Instrumentation (GEPI), PSL Research University (PSL)-PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), Institut Européen des membranes (IEM), Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS), Diamond Light Source, Harwell, Berks, England, AUTRES, Observatoire de Paris - Site de Paris (OP), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology [2007-2019] (Grenoble INP [2007-2019])-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology [2007-2019] (Grenoble INP [2007-2019])-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Paris Diderot - Paris 7 (UPD7)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Santé et de la Recherche Médicale (INSERM), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), and Universidade do Porto
Subjects: infrared: ISM, stars: formation, techniques: interferometric, Astrophysics::Solar and Stellar Astrophysics, techniques: high angular resolution, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], circumstellar matter, Astrophysics::Galaxy Astrophysics
Abstract: International audience; Context. The formation and the evolution of protoplanetary disks are important stages in the lifetime of stars. Terrestrial planets form or migrate within the innermost regions of these protoplanetary disks and so, the processes of disk evolution and planet formation are intrinsically linked. Studies of the dust distribution, composition, and evolution of these regions are crucial to understanding planet formation. Aims: We built a homogeneous observational dataset of Herbig Ae/Be disks with the aim of spatially resolving the sub au-scale region to gain a statistical understanding of their morphological and compositional properties, in addition to looking for correlations with stellar parameters, such as luminosity, mass, and age. Methods: We observed 27 Herbig Ae/Be stars with the GRAVITY instrument installed at the combined focus of the Very Large Telescope Interferometer (VLTI) and operating in the near-infrared K-band, focused on the K-band thermal continuum, which corresponds to stellar flux reprocessed by the dust grains. Our sample covers a large range of effective temperatures, luminosities, masses, and ages for the intermediate-mass star population. The circumstellar disks in our sample also cover a range of various properties in terms of reprocessed flux, flared or flat morphology, and gaps. We developed semi-physical geometrical models to fit our interferometric data. Results: Our best-fit models correspond to smooth and wide rings that support previous findings in the H-band, implying that wedge-shaped rims at the dust sublimation edge are favored. The measured closure phases are generally non-null with a median value of 10°, indicating spatial asymmetries of the intensity distributions. Multi-size grain populations could explain the closure phase ranges below 20-25° but other scenarios should be invoked to explain the largest ones. Our measurements extend the Radius-Luminosity relation to 104 L⊙ luminosity values and confirm the significant spread around the mean relation observed by PIONIER in the H-band. Gapped sources exhibit a large N-to-K band size ratio and large values of this ratio are only observed for the members of our sample that would be older than 1 Ma, less massive, and with lower luminosity. In the mass range of 2 M⊙, we do observe a correlation in the increase of the relative age with the transition from group II to group I, and an increase of the N-to-K size ratio. However, the size of the current sample does not yet permit us to invoke a clear, universal evolution mechanism across the Herbig Ae/Be mass range. The measured locations of the K-band emission in our sample suggest that these disks might be structured by forming young planets, rather than by depletion due to EUV, FUV, and X-ray photo-evaporation. GTO programs with run ID: 0103.C-0347; 0102.C-0408; 0101.C-0311; 0100.C-0278; 099.C-0667.
Published: 2019
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14. Images at the Highest Angular Resolution with GRAVITY: The Case of η Carinae

Author: Abuter, R., Accardo, M., Adler, T., Amorim, A., Anugu, N., Ávila, G., Bauböck, M., Benisty, M., Berger, J.-P., Bestenlehner, J. M., Beust, H., Blind, N., Bonnefoy, M., BONNET, H., Bourget, P., Bouvier, J., Brandner, W., Brast, R., Buron, A., Burtscher, L., Cantalloube, F., Caratti O Garatti, A., Caselli, P., Cassaing, F., Chapron, F., Charnay, B., Choquet, E., Clénet, Y., Collin, C., Coudé Du Foresto, V., Davies, R., Deen, C., Delplancke-Ströbele, F., Dembet, R., Derie, F., de Wit, W.-J., Dexter, J., De Zeeuw, T., Dougados, C., Dubus, G., Duvert, G., Ebert, M., Eckart, A., Eisenhauer, F., Esselborn, M., Eupen, F., Fédou, P., Ferreira, M. C., Finger, G., Förster Schreiber, N. M., Gao, F., García Dabó, C. E., Garcia Lopez, R., Garcia, P. J. V., Gendron, É., Genzel, R., Gerhard, O., Gil, J. P., Gillessen, S., Gonté, F., Gordo, P., Gratadour, D., Greenbaum, A., Grellmann, R., Grözinger, U., Guajardo, P., Guieu, S., Habibi, M., Haguenauer, P., Hans, O., Haubois, X., Haug, M., Haußmann, F., Henning, T., Hippler, S., Hönig, S. F., Horrobin, M., Huber, A., Hubert, Z., Hubin, N., Hummel, C. A., Jakob, G., Janssen, A., Jimenez Rosales, A., Jochum, L., Jocou, L., Kammerer, J., Karl, M., Kaufer, A., Kellner, S., Kendrew, S., Kern, L., Kervella, P., Kiekebusch, M., Kishimoto, M., Klarmann, L., Klein, R., Köhler, R., Kok, Y., Kolb, J., Koutoulaki, M., Kulas, M., Labadie, L., Lacour, S., Lagrange, A.-M., Lapeyrère, V., Laun, W., Lazareff, B., Le Bouquin, J.-B., Léna, P., Lenzen, R., Lévêque, S., Lin, C.-C., Lippa, M., Lutz, D., Magnard, Y., Maire, A.-L., Mehrgan, L., Mérand, A., Millour, F., Mollière, P., Moulin, T., Müller, A., Müller, E., Müller, F., Netzer, H., Neumann, U., Nowak, M., Oberti, S., Ott, T., Pallanca, L., Panduro, J., Pasquini, L., Paumard, T., Percheron, I., Perraut, K., Perrin, G., Peterson, B. M., Petrucci, P.-O., Pflüger, A., Pfuhl, O., Phan Duc, T., Pineda, J. E., Plewa, P. m., Popovic, D., Pott, J.-U., Prieto, A., Pueyo, L., Rabien, S., Ramírez, A., Ramos, J. R., Rau, C., Ray, T., Riquelme, M., Rodríguez-Coira, G., Rohloff, R.-R., Rouan, D., Rousset, G., Sanchez-Bermudez, J., Schartmann, M., Scheithauer, S., Schöller, M., Schuhler, N., Segura-Cox, D., Shangguan, J., Shimizu, T. T., Spyromilio, J., Sternberg, A., Stock, M. R., Straub, O., Straubmeier, C., Sturm, E., Suárez Valles, M., Tacconi, L. J., Thi, W.-F., Tristram, K. R. W., Valenzuela, J. J., Van Boekel, R., Van Dishoeck, E. F., Vermot, P., Vincent, F., Von fellenberg, S., Waisberg, I., Wang, J. J., Wank, I., Weber, J., Weigelt, G., Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Wittkowski, M., Woillez, J., Wolff, B., Yang, P., Yazici, S., Ziegler, D., Zins, G., and European Southern Observatory (ESO)
Subjects: [SDU]Sciences of the Universe [physics], Astrophysics::High Energy Astrophysical Phenomena, 0103 physical sciences, Astrophysics::Instrumentation and Methods for Astrophysics, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, 01 natural sciences
Abstract: The main goal of an interferometer is to probe the physics of astronomical objects at the highest possible angular resolution. The most intuitive way of doing this is by reconstructing images from the interferometric data. GRAVITY at the Very Large Telescope Interferometer (VLTI) has proven to be a fantastic instrument in this endeavour. In this article, we describe the reconstruction of the wind-wind collision cavity of the massive binary η Car with GRAVITY across two spectral lines: HeI and Brγ., Published in The Messenger vol. 178, pp. 31-33, December 2019.
Published: 2019
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15. Common functional networks in the mouse brain revealed by multi-centre resting-state fMRI analysis

Author: Grandjean, J., Canella, C., Anckaerts, C., Ayranci, G., Bougacha, S., Bienert, T., Buehlmann, D., Coletta, L., Gallino, D., Gass, N., Garin, C.M., Nadkarni, N.A., Hubner, N.S., Karatas, M., Komaki, Y., Kreitz, S., Mandino, F., Mechling, A.E., Sato, C., Sauer, K., Shah, D., Strobelt, S., Takata, N., Wank, I., Wu, T., Yahata, N., Yeow, L.Y., Yee, Y., Aoki, I., Chakravarty, M.M., Chang, W.T., Dhenain, M., Elverfeldt, D. von, Harsan, L.A., Hess, A., Jiang, T., Keliris, G.A., Lerch, J.P., Meyer-Lindenberg, A., Okano, H., Rudin, M., Sartorius, A., Linden, A. van der, Verhoye, M., Weber-Fahr, W., Wenderoth, N., Zerbi, V., Gozzi, A., Grandjean, J., Canella, C., Anckaerts, C., Ayranci, G., Bougacha, S., Bienert, T., Buehlmann, D., Coletta, L., Gallino, D., Gass, N., Garin, C.M., Nadkarni, N.A., Hubner, N.S., Karatas, M., Komaki, Y., Kreitz, S., Mandino, F., Mechling, A.E., Sato, C., Sauer, K., Shah, D., Strobelt, S., Takata, N., Wank, I., Wu, T., Yahata, N., Yeow, L.Y., Yee, Y., Aoki, I., Chakravarty, M.M., Chang, W.T., Dhenain, M., Elverfeldt, D. von, Harsan, L.A., Hess, A., Jiang, T., Keliris, G.A., Lerch, J.P., Meyer-Lindenberg, A., Okano, H., Rudin, M., Sartorius, A., Linden, A. van der, Verhoye, M., Weber-Fahr, W., Wenderoth, N., Zerbi, V., and Gozzi, A.
Abstract: Contains fulltext : 219632.pdf (publisher's version ) (Open Access), Preclinical applications of resting-state functional magnetic resonance imaging (rsfMRI) offer the possibility to non-invasively probe whole-brain network dynamics and to investigate the determinants of altered network signatures observed in human studies. Mouse rsfMRI has been increasingly adopted by numerous laboratories worldwide. Here we describe a multi-centre comparison of 17 mouse rsfMRI datasets via a common image processing and analysis pipeline. Despite prominent cross-laboratory differences in equipment and imaging procedures, we report the reproducible identification of several large-scale resting-state networks (RSN), including a mouse default-mode network, in the majority of datasets. A combination of factors was associated with enhanced reproducibility in functional connectivity parameter estimation, including animal handling procedures and equipment performance. RSN spatial specificity was enhanced in datasets acquired at higher field strength, with cryoprobes, in ventilated animals, and under medetomidine-isoflurane combination sedation. Our work describes a set of representative RSNs in the mouse brain and highlights key experimental parameters that can critically guide the design and analysis of future rodent rsfMRI investigations.
Published: 2020

16. Spatially Resolving the Quasar Broad Emission Line Region

Author: Abuter, R., Accardo, M., Adler, T., Amorim, A., Anugu, N., Ávila, G., Bauböck, M., Benisty, M., Berger, J.-P., Bestenlehner, J.M., Beust, H., Blind, N., Bonnefoy, M., Bonnet, H., Bourget, P., Bouvier, J., Brandner, W., Brast, R., Buron, A., Burtscher, L.H., Cantalloube, F., Caratti, O, Garatti, A., Caselli, P., Cassaing, F., Chapron, F., Charnay, B., Choquet, É., Clénet, Y., Collin, C., Coudé Du, Foresto, V., Davies, R., Deen, C., Delplancke-Ströbele, F., Dembet, R., Derie, F., De Wit, W.-J., Dexter, J., Zeeuw, T. de, Dougados, C., Dubus, G., Duvert, G., Ebert, M., Eckart, A., Eisenhauer, F., Esselborn, M., Eupen, F., Fédou, P., Ferreira, M.C., Finger, G., Förster Schreiber, N.M., Gao, F., García Dabó, C.E., Garcia Lopez, R., Garcia, P.J.V., Gendron, É., Genzel, R., Gerhard, O., Gil, J.P., Gillessen, S., Gonté, F., Gordo, P., Gratadour, D., Greenbaum, A., Grellmann, R., Grözinger, U., Guajardo, P., Guieu, S., Habibi, M., Haguenauer, P., Hans, O., Haubois, X., Haug, M., Haußmann, F., Henning, T., Hippler, S., Hönig, S.F., Horrobin, M., Huber, A., Hubert, Z., Hubin, N., Hummel, C.~A., Jakob, G., Janssen, A., Jimenez Rosales, A., Jochum, L., Jocou, L., Kammerer, J., Karl, M., Kaufer, A., Kellner, S., Kendrew, S., Kern, L., Kervella, P., Kiekebusch, M., Kishimoto, M., Klarmann, L., Klein, R., Köhler, R., Kok, Y., Kolb, J., Koutoulaki, M., Kulas, M., Labadie, L., Lacour, S., Lagrange, A.-M., Lapeyrère, V., Laun, W., Lazareff, B., Le Bouquin, J.-B., Léna, P., Lenzen, R., Lévêque, S., Lin, C.-C., Lippa, M., Lutz, D., Magnard, Y., Maire, A.-L., Mehrgan, L., Mérand, A., Millour, F., Mollière, P., Moulin, T., Müller, A., Müller, E., Müller, F., Netzer, H., Neumann, U., Nowak, M., Oberti, S., Ott, T., Pallanca, L., Panduro, J., Pasquini, L., Paumard, T., Percheron, I., Perraut, K., Perrin, G., Peterson, B.M., Petrucci, P.-O., Pflüger, A., Pfuhl, O., Phan Duc, T., Pineda, J.E., Plewa, P.M., Popovic, D., Pott, J.-U., Prieto, A., Pueyo, L., Rabien, S., Ramírez, A., Ramos, J.R., Rau, C., Ray, T., Riquelme, M., Rodríguez-Coira, G., Rohloff, R.-R., Rouan, D., Rousset, G., Sanchez-Bermudez, J., Schartmann, M., Scheithauer, S., Schöller, M., Schuhler, N., Segura-Cox, D., Shangguan, J., Shimizu, T.T., Spyromilio, J., Sternberg, A., Stock, M.R., Straub, O., Straubmeier, C., Sturm, E., Suárez Valles, M., Tacconi, L.J., Thi, W.-F., Tristram, K.R.W., Valenzuela, J.J., Boekel, R. van, Dishoeck, E.F. van, Vermot, P., Vincent, F., Von Fellenberg, S., Waisberg, I., Wang, J.J., Wank, I., Weber, J., Weigelt, G., Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Wittkowski, M., Woillez, J., Wolff, B., Yang, P., Yazici, S., Ziegler, D., Zins, G., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: General Relativity and Quantum Cosmology, [SDU]Sciences of the Universe [physics], Astrophysics::High Energy Astrophysical Phenomena, 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 010303 astronomy & astrophysics, 01 natural sciences, Astrophysics::Galaxy Astrophysics
Abstract: The angular resolution of the Very Large Telescope Interferometer (VLTI) and the excellent sensitivity of GRAVITY have led to the first detection of spatially resolved kinematics of high velocity atomic gas near an accreting super- massive black hole, revealing rotation on sub-parsec scales in the quasar 3C 273 at a distance of 550 Mpc. The observations can be explained as the result of circular orbits in a thick disc configuration around a 300 million solar mass black hole. Within an ongoing Large Programme, this capability will be used to study the kinematics of atomic gas and its relation to hot dust in a sample of quasars and Seyfert galaxies. We will measure a new radius-luminosity relation from spatially resolved data and test the current methods used to measure black hole mass in large surveys., Published in The Messenger vol. 178, pp. 20-24, December 2019.
Published: 2019
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17. First direct detection of an exoplanet by optical interferometry. Astrometry and K-band spectroscopy of HR 8799 e

Author: Collaboration, G., Lacour, S., Nowak, M., Wang, J., Pfuhl, O., Eisenhauer, F., Abuter, R., Amorim, A., Anugu, N., Benisty, M., Berger, J., Beust, H., Blind, N., Bonnefoy, M., Bonnet, H., Bourget, P., Brandner, W., Buron, A., Collin, C., Charnay, B., Chapron, F., Clénet, Y., Coudé Du Foresto, V., de Zeeuw, P., Deen, C., Dembet, R., Dexter, J., Duvert, G., Eckart, A., Förster Schreiber, N., Fédou, P., Garcia, P., Garcia Lopez, R., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Gordo, P., Greenbaum, A., Habibi, M., Haubois, X., Haußmann, F., Henning, T., Hippler, S., Horrobin, M., Hubert, Z., Jimenez Rosales, A., Jocou, L., Kendrew, S., Kervella, P., Kolb, J., Lagrange, A., Lapeyrère, V., Le Bouquin, J., Léna, P., Lippa, M., Lenzen, R., Maire, A., Mollière, P., Ott, T., Paumard, T., Perraut, K., Perrin, G., Pueyo, L., Rabien, S., Ramírez, A., Rau, C., Rodríguez-Coira, G., Rousset, G., Sanchez-Bermudez, J., Scheithauer, S., Schuhler, N., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L., Vincent, F., van Dishoeck, E., von Fellenberg, S., Wank, I., Waisberg, I., Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Woillez, J., Yazici, S., Ziegler, D., and Zins, G.
Abstract: Aims: 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 of high contrast observations, enabling the direct observation of exoplanets. We demonstrate the technique on HR 8799, a young planetary system composed of four known giant exoplanets. Methods: We used the GRAVITY fringe tracker to lock the fringes on the central star, and integrated off-axis on the HR 8799 e planet situated at 390 mas from the star. Data reduction included post-processing to remove the flux leaking from the central star and to extract the coherent flux of the planet. The inferred K band spectrum of the planet has a spectral resolution of 500. We also derive the astrometric position of the planet relative to the star with a precision on the order of 100 Œºas. Results: The GRAVITY astrometric measurement disfavors perfectly coplanar stable orbital solutions. A small adjustment of a few degrees to the orbital inclination of HR 8799 e can resolve the tension, implying that the orbits are close to, but not strictly coplanar. The spectrum, with a signal-to-noise ratio of ‚âà5 per spectral channel, is compatible with a late-type L brown dwarf. Using Exo-REM synthetic spectra, we derive a temperature of 1150 ¬± 50 K and a surface gravity of 104.3 ¬± 0.3 cm s2. This corresponds to a radius of 1.17-0.11+0.13 RJup and a mass of 10-4+7 MJup, which is an independent confirmation of mass estimates from evolutionary models. Our results demonstrate the power of interferometry for the direct detection and spectroscopic study of exoplanets at close angular separations from their stars. The reduced spectrum is available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz- bin/qcat?J/A+A/623/L11.Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, ID 60.A-9102(G).
Published: 2019

18. Multiple Star Systems in the Orion Nebula

Author: Abuter, R., Accardo, M., Adler, T., Amorim, A., Anugu, N., Ávila, G., Bauböck, M., Benisty, M., Berger, J.-P., Bestenlehner, J. M., Beust, H., Blind, N., Bonnefoy, M., BONNET, H., Bourget, P., Bouvier, J., Brandner, W., Brast, R., Buron, A., Burtscher, L., Cantalloube, F., Caratti O Garatti, A., Caselli, P., Cassaing, F., Chapron, F., Charnay, B., Choquet, E., Clénet, Y., Collin, C., Coudé Du Foresto, V., Davies, R., Deen, C., Delplancke-Ströbele, F., Dembet, R., Derie, F., de Wit, W.-J., Dexter, J., De Zeeuw, T., Dougados, C., Dubus, G., Duvert, G., Ebert, M., Eckart, A., Eisenhauer, F., Esselborn, M., Eupen, F., Fédou, P., Ferreira, M. C., Finger, G., Förster Schreiber, N. M., Gao, F., García Dabó, C. E., Garcia Lopez, R., Garcia, P. J. V., Gendron, É., Genzel, R., Gerhard, O., Gil, J. P., Gillessen, S., Gonté, F., Gordo, P., Gratadour, D., Greenbaum, A., Grellmann, R., Grözinger, U., Guajardo, P., Guieu, S., Habibi, M., Haguenauer, P., Hans, O., Haubois, X., Haug, M., Haußmann, F., Henning, T., Hippler, S., Hönig, S. F., Horrobin, M., Huber, A., Hubert, Z., Hubin, N., Hummel, C. A., Jakob, G., Janssen, A., Jimenez Rosales, A., Jochum, L., Jocou, L., Kammerer, J., Karl, M., Kaufer, A., Kellner, S., Kendrew, S., Kern, L., Kervella, P., Kiekebusch, M., Kishimoto, M., Klarmann, L., Klein, R., Köhler, R., Kok, Y., Kolb, J., Koutoulaki, M., Kulas, M., Labadie, L., Lacour, S., Lagrange, A.-M., Lapeyrère, V., Laun, W., Lazareff, B., Le Bouquin, J.-B., Léna, P., Lenzen, R., Lévêque, S., Lin, C.-C., Lippa, M., Lutz, D., Magnard, Y., Maire, A.-L., Mehrgan, L., Mérand, A., Millour, F., Mollière, P., Moulin, T., Müller, A., Müller, E., Müller, F., Netzer, H., Neumann, U., Nowak, M., Oberti, S., Ott, T., Pallanca, L., Panduro, J., Pasquini, L., Paumard, T., Percheron, I., Perraut, K., Perrin, G., Peterson, B. M., Petrucci, P.-O., Pflüger, A., Pfuhl, O., Phan Duc, T., Pineda, J. E., Plewa, P. m., Popovic, D., Pott, J.-U., Prieto, A., Pueyo, L., Rabien, S., Ramírez, A., Ramos, J. R., Rau, C., Ray, T., Riquelme, M., Rodríguez-Coira, G., Rohloff, R.-R., Rouan, D., Rousset, G., Sanchez-Bermudez, J., Schartmann, M., Scheithauer, S., Schöller, M., Schuhler, N., Segura-Cox, D., Shangguan, J., Shimizu, T. T., Spyromilio, J., Sternberg, A., Stock, M. R., Straub, O., Straubmeier, C., Sturm, E., Suárez Valles, M., Tacconi, L. J., Thi, W.-F., Tristram, K. R. W., Valenzuela, J. J., Van Boekel, R., Van Dishoeck, E. F., Vermot, P., Vincent, F., Von fellenberg, S., Waisberg, I., Wang, J. J., Wank, I., Weber, J., Weigelt, G., Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Wittkowski, M., Woillez, J., Wolff, B., Yang, P., Yazici, S., Ziegler, D., Zins, G., and European Southern Observatory (ESO)
Subjects: [SDU]Sciences of the Universe [physics], Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: GRAVITY observations reveal that most massive stars in the Orion Trapezium cluster live in multiple systems. Our deep, milliarcsecond-resolution interferometry fills the gap at 1–100 astronomical units (au), which is not accessible to traditional imaging and spectroscopy, but is crucial to uncovering the mystery of high-mass star formation.The new observations find a significantly higher companion fraction than earlier studies of mostly OB associations. The observed distribution of mass ratios declines steeply with mass and follows a Salpeter power-law initial mass function. The observations therefore exclude stellar mergers as the dominant formation mechanism for massive stars in Orion., Published in The Messenger vol. 178, pp. 36-38, December 2019.
Published: 2019
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19. GRAVITY - Reaching out to SgrA* with VLTI

Author: Abuter, R., Amorim, A., Anugu, N., Bauböck, M., Benisty, M., Berger, J., Blind, N., Bonnet, H., Brandner, W., Buron, A., Collin, C., Chapron, F., Clénet, Y., Coudé du Foresto, V., de Zeeuw, P., Deen, C., Delplancke-Ströbele, F., Dembet, R., Dexter, J., Duvert, G., Eckart, A., Eisenhauer, F., Finger, G., Förster Schreiber, N., Fédou, P., Garcia, P., Garcia Lopez, R., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Gordo, P., Habibi, M., Haubois, X., Haug, M., Haußmann, F., Henning, T., Hippler, S., Horrobin, M., Hubert, Z., Hubin, N., Jimenez Rosales, A., Jochum, L., Jocou, L., Kaufer, A., Kellner, S., Kendrew, S., Kervella, P., Kok, Y., Kulas, M., Lacour, S., Lapeyrère, V., Lazareff, V., Le Bouquin, J., Léna, P., Lippa, M., Lenzen, R., Mérand, A., Müler, E., Neumann, U., Ott, T., Palanca, L., Paumard, T., Pasquini, L., Perraut, K., Perrin, G., Pfuhl, O., Plewa, P., Rabien, S., Ramírez, A., Ramos, J., Rau, C., Rodríguez-Coira, G., Rohloff, R., Rousset, G., Sanchez-Bermudez, J., Scheithauer, S., Schöller, M., Schuler, N., Spyromilio, J., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L., Tristram, K., Vincent, F., von Fellenberg, S., Wank, I., Waisberg, I., Widmann, F., Wieprecht, F., Wiezorrek, E., Woillez, J., Yazici, S., Ziegler, S., and Zins, G.
Subjects: Astrophysics::Instrumentation and Methods for Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: As one of the 2nd generation of interferometric instruments in VLTI, GRAVITY was installed at the end of 2015 and has been observing the Galactic Center since May 2016. With the goal to reach an accuracy of tens of micro arcseconds, it is able to perform the most precise astrometric measurement of SgrA* to date. For that purpose, GRAVITY combines the light collected (coherently) from of all the 8 m UTs or the four 1.8 m ATs providing infrared wavefront sensing to control the telescope adaptive optics, two interferometric beam combiners (one for fringe-tracking and one for the science object), an acquisition camera and various laser guiding systems for beam stabilization, as well as a dedicated laser metrology to trace the optical path length differences for narrow angle astrometry. Operating in K band with an active stabilization of the science channel, GRAVITY is able to increase the typical integration time from a few milliseconds (the typical atmospheric coherence time) to minutes, which implies a big leap in sensitivity allowing to observe fainter objects (K=19 in science detector) with the power of a 130m baseline interferometer, as it is the close environment of the supermassive black hole located in the center of our Galaxy.
Published: 2019

20. Spatially Resolving the Inner Gaseous Disc of the Herbig Star 51 Oph through its CO Ro-vibration Emission

Author: Abuter, R., Accardo, M., Adler, T., Amorim, A., Anugu, N., Ávila, G., Bauböck, M., Benisty, M., Berger, J.-P., Bestenlehner, J. M., Beust, H., Blind, N., Bonnefoy, M., BONNET, H., Bourget, P., Bouvier, J., Brandner, W., Brast, R., Buron, A., Burtscher, L., Cantalloube, F., Caratti O Garatti, A., Caselli, P., Cassaing, F., Chapron, F., Charnay, B., Choquet, E., Clénet, Y., Collin, C., Coudé Du Foresto, V., Davies, R., Deen, C., Delplancke-Ströbele, F., Dembet, R., Derie, F., de Wit, W.-J., Dexter, J., De Zeeuw, T., Dougados, C., Dubus, G., Duvert, G., Ebert, M., Eckart, A., Eisenhauer, F., Esselborn, M., Eupen, F., Fédou, P., Ferreira, M. C., Finger, G., Förster Schreiber, N. M., Gao, F., García Dabó, C. E., Garcia Lopez, R., Garcia, P. J. V., Gendron, É., Genzel, R., Gerhard, O., Gil, J. P., Gillessen, S., Gonté, F., Gordo, P., Gratadour, D., Greenbaum, A., Grellmann, R., Grözinger, U., Guajardo, P., Guieu, S., Habibi, M., Haguenauer, P., Hans, O., Haubois, X., Haug, M., Haußmann, F., Henning, T., Hippler, S., Hönig, S. F., Horrobin, M., Huber, A., Hubert, Z., Hubin, N., Hummel, C. A., Jakob, G., Janssen, A., Jimenez Rosales, A., Jochum, L., Jocou, L., Kammerer, J., Karl, M., Kaufer, A., Kellner, S., Kendrew, S., Kern, L., Kervella, P., Kiekebusch, M., Kishimoto, M., Klarmann, L., Klein, R., Köhler, R., Kok, Y., Kolb, J., Koutoulaki, M., Kulas, M., Labadie, L., Lacour, S., Lagrange, A.-M., Lapeyrère, V., Laun, W., Lazareff, B., Le Bouquin, J.-B., Léna, P., Lenzen, R., Lévêque, S., Lin, C.-C., Lippa, M., Lutz, D., Magnard, Y., Maire, A.-L., Mehrgan, L., Mérand, A., Millour, F., Mollière, P., Moulin, T., Müller, A., Müller, E., Müller, F., Netzer, H., Neumann, U., Nowak, M., Oberti, S., Ott, T., Pallanca, L., Panduro, J., Pasquini, L., Paumard, T., Percheron, I., Perraut, K., Perrin, G., Peterson, B. M., Petrucci, P.-O., Pflüger, A., Pfuhl, O., Phan Duc, T., Pineda, J. E., Plewa, P. m., Popovic, D., Pott, J.-U., Prieto, A., Pueyo, L., Rabien, S., Ramírez, A., Ramos, J. R., Rau, C., Ray, T., Riquelme, M., Rodríguez-Coira, G., Rohloff, R.-R., Rouan, D., Rousset, G., Sanchez-Bermudez, J., Schartmann, M., Scheithauer, S., Schöller, M., Schuhler, N., Segura-Cox, D., Shangguan, J., Shimizu, T. T., Spyromilio, J., Sternberg, A., Stock, M. R., Straub, O., Straubmeier, C., Sturm, E., Suárez Valles, M., Tacconi, L. J., Thi, W.-F., Tristram, K. R. W., Valenzuela, J. J., Van Boekel, R., Van Dishoeck, E. F., Vermot, P., Vincent, F., Von fellenberg, S., Waisberg, I., Wang, J. J., Wank, I., Weber, J., Weigelt, G., Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Wittkowski, M., Woillez, J., Wolff, B., Yang, P., Yazici, S., Ziegler, D., Zins, G., and European Southern Observatory (ESO)
Subjects: [SDU]Sciences of the Universe [physics], Astrophysics::Instrumentation and Methods for Astrophysics, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: Near-infrared interferometry gives us the opportunity to spatially resolve the circumstellar environment of young stars at sub-astronomical-unit (au) scales, which a standalone telescope could not reach. In particular, the sensitivity of GRAVITY on the VLTI allows us to spatially resolve the CO overtone emission at 2.3 microns. In this article, we present a new method of using the model of the CO spectrum to reconstruct the differential phase signal and extract the geometry and size of the emitting region., Published in The Messenger vol. 178, pp. 40-42, December 2019.
Published: 2019
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21. An Image of the Dust Sublimation Region in the Nucleus of NGC 1068

Author: Abuter, R., Accardo, M., Adler, T., Amorim, A., Anugu, N., Ávila, G., Bauböck, M., Benisty, M., Berger, J.-P., Bestenlehner, J. M., Beust, H., Blind, N., Bonnefoy, M., BONNET, H., Bourget, P., Bouvier, J., Brandner, W., Brast, R., Buron, A., Burtscher, L., Cantalloube, F., Caratti O Garatti, A., Caselli, P., Cassaing, F., Chapron, F., Charnay, B., Choquet, E., Clénet, Y., Collin, C., Coudé Du Foresto, V., Davies, R., Deen, C., Delplancke-Ströbele, F., Dembet, R., Derie, F., de Wit, W.-J., Dexter, J., De Zeeuw, T., Dougados, C., Dubus, G., Duvert, G., Ebert, M., Eckart, A., Eisenhauer, F., Esselborn, M., Eupen, F., Fédou, P., Ferreira, M. C., Finger, G., Förster Schreiber, N. M., Gao, F., García Dabó, C. E., Garcia Lopez, R., Garcia, P. J. V., Gendron, É., Genzel, R., Gerhard, O., Gil, J. P., Gillessen, S., Gonté, F., Gordo, P., Gratadour, D., Greenbaum, A., Grellmann, R., Grözinger, U., Guajardo, P., Guieu, S., Habibi, M., Haguenauer, P., Hans, O., Haubois, X., Haug, M., Haußmann, F., Henning, T., Hippler, S., Hönig, S. F., Horrobin, M., Huber, A., Hubert, Z., Hubin, N., Hummel, C. A., Jakob, G., Janssen, A., Jimenez Rosales, A., Jochum, L., Jocou, L., Kammerer, J., Karl, M., Kaufer, A., Kellner, S., Kendrew, S., Kern, L., Kervella, P., Kiekebusch, M., Kishimoto, M., Klarmann, L., Klein, R., Köhler, R., Kok, Y., Kolb, J., Koutoulaki, M., Kulas, M., Labadie, L., Lacour, S., Lagrange, A.-M., Lapeyrère, V., Laun, W., Lazareff, B., Le Bouquin, J.-B., Léna, P., Lenzen, R., Lévêque, S., Lin, C.-C., Lippa, M., Lutz, D., Magnard, Y., Maire, A.-L., Mehrgan, L., Mérand, A., Millour, F., Mollière, P., Moulin, T., Müller, A., Müller, E., Müller, F., Netzer, H., Neumann, U., Nowak, M., Oberti, S., Ott, T., Pallanca, L., Panduro, J., Pasquini, L., Paumard, T., Percheron, I., Perraut, K., Perrin, G., Peterson, B. M., Petrucci, P.-O., Pflüger, A., Pfuhl, O., Phan Duc, T., Pineda, J. E., Plewa, P. m., Popovic, D., Pott, J.-U., Prieto, A., Pueyo, L., Rabien, S., Ramírez, A., Ramos, J. R., Rau, C., Ray, T., Riquelme, M., Rodríguez-Coira, G., Rohloff, R.-R., Rouan, D., Rousset, G., Sanchez-Bermudez, J., Schartmann, M., Scheithauer, S., Schöller, M., Schuhler, N., Segura-Cox, D., Shangguan, J., Shimizu, T. T., Spyromilio, J., Sternberg, A., Stock, M. R., Straub, O., Straubmeier, C., Sturm, E., Suárez Valles, M., Tacconi, L. J., Thi, W.-F., Tristram, K. R. W., Valenzuela, J. J., Van Boekel, R., Van Dishoeck, E. F., Vermot, P., Vincent, F., Von fellenberg, S., Waisberg, I., Wang, J. J., Wank, I., Weber, J., Weigelt, G., Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Wittkowski, M., Woillez, J., Wolff, B., Yang, P., Yazici, S., Ziegler, D., Zins, G., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU]Sciences of the Universe [physics], Astrophysics::High Energy Astrophysical Phenomena, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 010303 astronomy & astrophysics, 01 natural sciences, Astrophysics::Galaxy Astrophysics
Abstract: The superb resolution of the Very Large Telescope Interferometer (VLTI) and the unrivalled sensitivity of GRAVITY have allowed us to reconstruct the first detailed image of the dust sublimation region in an active galaxy. In the nearby archetypal Seyfert 2 galaxy NGC 1068, the 2 µm continuum emission traces a highly inclined thin ring-like structure with a radius of 0.24 pc. The observed morphology challenges the picture of a geometrically and optically thick torus., Published in The Messenger vol. 178, pp. 24-26, December 2019.
Published: 2019
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22. Probing the Discs of Herbig Ae/Be Stars at Terrestrial Orbits

Author: Abuter, R., Accardo, M., Adler, T., Amorim, A., Anugu, N., Ávila, G., Bauböck, M., Benisty, M., Berger, J.-P., Bestenlehner, J. M., Beust, H., Blind, N., Bonnefoy, M., BONNET, H., Bourget, P., Bouvier, J., Brandner, W., Brast, R., Buron, A., Burtscher, L., Cantalloube, F., Caratti O Garatti, A., Caselli, P., Cassaing, F., Chapron, F., Charnay, B., Choquet, E., Clénet, Y., Collin, C., Coudé Du Foresto, V., Davies, R., Deen, C., Delplancke-Ströbele, F., Dembet, R., Derie, F., de Wit, W.-J., Dexter, J., De Zeeuw, T., Dougados, C., Dubus, G., Duvert, G., Ebert, M., Eckart, A., Eisenhauer, F., Esselborn, M., Eupen, F., Fédou, P., Ferreira, M. C., Finger, G., Förster Schreiber, N. M., Gao, F., García Dabó, C. E., Garcia Lopez, R., Garcia, P. J. V., Gendron, É., Genzel, R., Gerhard, O., Gil, J. P., Gillessen, S., Gonté, F., Gordo, P., Gratadour, D., Greenbaum, A., Grellmann, R., Grözinger, U., Guajardo, P., Guieu, S., Habibi, M., Haguenauer, P., Hans, O., Haubois, X., Haug, M., Haußmann, F., Henning, T., Hippler, S., Hönig, S. F., Horrobin, M., Huber, A., Hubert, Z., Hubin, N., Hummel, C. A., Jakob, G., Janssen, A., Jimenez Rosales, A., Jochum, L., Jocou, L., Kammerer, J., Karl, M., Kaufer, A., Kellner, S., Kendrew, S., Kern, L., Kervella, P., Kiekebusch, M., Kishimoto, M., Klarmann, L., Klein, R., Köhler, R., Kok, Y., Kolb, J., Koutoulaki, M., Kulas, M., Labadie, L., Lacour, S., Lagrange, A.-M., Lapeyrère, V., Laun, W., Lazareff, B., Le Bouquin, J.-B., Léna, P., Lenzen, R., Lévêque, S., Lin, C.-C., Lippa, M., Lutz, D., Magnard, Y., Maire, A.-L., Mehrgan, L., Mérand, A., Millour, F., Mollière, P., Moulin, T., Müller, A., Müller, E., Müller, F., Netzer, H., Neumann, U., Nowak, M., Oberti, S., Ott, T., Pallanca, L., Panduro, J., Pasquini, L., Paumard, T., Percheron, I., Perraut, K., Perrin, G., Peterson, B. M., Petrucci, P.-O., Pflüger, A., Pfuhl, O., Phan Duc, T., Pineda, J. E., Plewa, P. m., Popovic, D., Pott, J.-U., Prieto, A., Pueyo, L., Rabien, S., Ramírez, A., Ramos, J. R., Rau, C., Ray, T., Riquelme, M., Rodríguez-Coira, G., Rohloff, R.-R., Rouan, D., Rousset, G., Sanchez-Bermudez, J., Schartmann, M., Scheithauer, S., Schöller, M., Schuhler, N., Segura-Cox, D., Shangguan, J., Shimizu, T. T., Spyromilio, J., Sternberg, A., Stock, M. R., Straub, O., Straubmeier, C., Sturm, E., Suárez Valles, M., Tacconi, L. J., Thi, W.-F., Tristram, K. R. W., Valenzuela, J. J., Van Boekel, R., Van Dishoeck, E. F., Vermot, P., Vincent, F., Von fellenberg, S., Waisberg, I., Wang, J. J., Wank, I., Weber, J., Weigelt, G., Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Wittkowski, M., Woillez, J., Wolff, B., Yang, P., Yazici, S., Ziegler, D., Zins, G., and European Southern Observatory (ESO)
Subjects: [SDU]Sciences of the Universe [physics], Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: More than 4000 exoplanets are known to date in systems that differ greatly from our Solar System. In particular, inner exoplanets tend to follow orbits around their parent star that are much more compact than that of Earth. These systems are also extremely diverse, covering a range of intrinsic properties. Studying the main physi- cal processes at play in the innermost regions of the protoplanetary discs is crucial to understanding how these planets form and migrate so close to their host. With GRAVITY, we focused on the study of near-infrared emission of a sample of young intermediate- mass stars, the Herbig Ae/Be stars., Published in The Messenger vol. 178, pp. 38-40, December 2019.
Published: 2019
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23. GRAVITY chromatic imaging of η Car’s core: Milliarcsecond resolution imaging of the wind-wind collision zone (Brγ, He I)

Author: Sanchez-Bermudez, J., Weigelt, G., Bestenlehner, J.M., Kervella, P., Brandner, W., Henning, T., Mueller, A., Perrin, G., Pott, J.-U., Schoeller, M., van Boeke, R., Abuter, R., Accardo, M., Amorim, A., Anugu, N., Avila, G., Benisty, M., Berger, J.P., Blind, N., Bonnet, H., Bourget, P., Brast, R., Buron, A., Cantalloube, F., Garatti, A.C.O., Cassaing, F., Chapron, F., Choquet, E., Clenet, Y., Collin, C., du Foresto, V.C., de Wit, W., de Zeeuw, T., Deen, C., Delplancke-Stroebele, F., Dembet, R., Derie, F., Dexter, J., Duvert, G., Ebert, M., Eckart, A., Eisenhauer, F., Esselborn, M., Fedou, P., Garcia, P.J.V., Dabo, C.E.G., Lopez, R.G., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Haubois, X., Haug, M., Haussmann, F., Hippler, S., Horrobin, M., Huber, A., Hubert, Z., Hubin, N., Hummel, C.A., Jakob, G., Jochum, L., Jocou, L., Karl, M., Kaufer, A., Kellner, S., Kendrew, S., Kern, L., Kiekebusch, M., Klein, R., Kolb, J., Kulas, M., Lacour, S., Lapeyrere, V., Lazareff, B., Le Bouquin, J.-B., Lena, P., Lenzen, R., Leveque, S., Lippa, M., Magnard, Y., Mehrgan, L., Mellein, M., Merand, A., Moreno-Ventas, J., Moulin, T., Mueller, E., Mueller, F., Neumann, U., Oberti, S., Ott, T., Pallanca, L., Panduro, J., Pasquini, L., Paumard, T., Percheron, I., Perraut, K., Petrucci, P.-O., Pflueger, A., Pfuhl, O., Duc, T.P., Plewa, P.M., Popovic, D., Rabien, S., Ramirez, A., Ramos, J., Rau, C., Riquelme, M., Rodriguez-Coira, G., Rohloff, R.-R., Rosales, A., Rousset, G., Scheithauer, S., Schuhler, N., Spyromilio, J., Straub, O., Straubmeier, C., Sturm, E., Suarez, M., Tristram, K.R.W., Ventura, N., Vincent, F., Waisberg, I., Wank, I., Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Wittkowski, M., Woillez, J., Wolff, B., Yazici, S., Ziegler, D., Zins, G., and Collaboration, GRAVITY
Subjects: Astrophysics::Solar and Stellar Astrophysics
Abstract: Context. η Car is one of the most intriguing luminous blue variables in the Galaxy. Observations and models of the X-ray, ultraviolet, optical, and infrared emission suggest a central binary in a highly eccentric orbit with a 5.54 yr period residing in its core. 2D and 3D radiative transfer and hydrodynamic simulations predict a primary with a dense and slow stellar wind that interacts with the faster and lower density wind of the secondary. The wind-wind collision scenario suggests that the secondary’s wind penetrates the primary’s wind creating a low-density cavity in it, with dense walls where the two winds interact. However, the morphology of the cavity and its physical properties are not yet fully constrained.\ud \ud Aims. We aim to trace the inner ∼5–50 au structure of η Car’s wind-wind interaction, as seen through Brγ and, for the first time, through the He I 2s-2p line.\ud \ud Methods. We have used spectro-interferometric observations with the K-band beam-combiner GRAVITY at the VLTI. The analyses of the data include (i) parametrical model-fitting to the interferometric observables, (ii) a CMFGEN model of the source’s spectrum, and (iii) interferometric image reconstruction.\ud \ud Results. Our geometrical modeling of the continuum data allows us to estimate its FWHM angular size close to 2 mas and an elongation ratio ϵ = 1.06 ± 0.05 over a PA = 130° ± 20°. Our CMFGEN modeling of the spectrum helped us to confirm that the role of the secondary should be taken into account to properly reproduce the observed Brγ and He I lines. Chromatic images across the Brγ line reveal a southeast arc-like feature, possibly associated to the hot post-shocked winds flowing along the cavity wall. The images of the He I 2s-2p line served to constrain the 20 mas (∼50 au) structure of the line-emitting region. The observed morphology of He I suggests that the secondary is responsible for the ionized material that produces the line profile. Both the Brγ and the He I 2s-2p maps are consistent with previous hydrodynamical models of the colliding wind scenario. Future dedicated simulations together with an extensive interferometric campaign are necessary to refine our constraints on the wind and stellar parameters of the binary, which finally will help us predict the evolutionary path of η Car.
Published: 2018

24. GRAVITY - Reaching out to SgrA* with VLTI

Author: Abuter, R., Amorim, A., Anugu, N, Bauböck, M, Benisty, M., Berger, J., Blind, N., Bonnet, H, Brandner, W., Buron, A, Collin, C., Chapron, F., Clénet, Y., Coudé Du Foresto, V., De Zeeuw, P, Deen, C, Delplancke-Ströbele, F, Dembet, R., Dexter, J, Duvert, G., Eckart, A., Eisenhauer, F., Finger, G, Förster Schreiber, N, Fédou, P, GARCIA, P, Garcia Lopez, R, Gao, F, Gendron, E, Genzel, R, Gillessen, S, Gordo, P, Habibi, M, Haubois, X, Haug, M, Haußmann, F, Henning, Th, Hippler, S, Horrobin, M., Hubert, Z, Hubin, N, Rosales, A, Jochum, L, Jocou, L, Kaufer, A, Kellner, S, Kendrew, S, Kervella, P, Kok, Y, Kulas, M, Lacour, S, Lapeyrère, V, Lazareff, B, Le Bouquin, J.-B, Léna, P, Lippa, M, Lenzen, R, Mérand, A, Müler, E, Neumann, U, Ott, T, Palanca, L, Paumard, T, Pasquini, L, Perraut, K, Perrin, G, Pfuhl, O, Plewa, P, Rabien, S, Ramírez, A, Ramos, J, Rau, C, Rodríguez-Coira, G, Rohloff, R.-R, Rousset, G, Sanchez-Bermudez, J, Scheithauer, S, Schöller, M, Schuler, N, Spyromilio, J, Straub, O, Straubmeier, C., Sturm, E, Tacconi, L, Tristram, K, Vincent, F, Von Fellenberg, S, Wank, I, Waisberg, I, Widmann, F, Wieprecht, E, Wiest, M, Wiezorrek, E, Woillez, J, Yazici, S, Ziegler, D, Zins, G, European Southern Observatory (ESO), SIM/IDL Faculdade de Ciências da Universidade de Lisboa (FCUL), University of Lisboa, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), STMicroelectronics [Crolles] (ST-CROLLES), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Max-Planck-Institut für Radioastronomie (MPIFR), Max Planck Institute for Extraterrestrial Physics (MPE), Universität zu Köln, Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], [SDU]Sciences of the Universe [physics]
Abstract: International audience; As one of the 2nd generation of interferometric instruments in VLTI, GRAVITY was in-stalled at the end of 2015 and has been observing the Galactic Center since May 2016. Withthe goal to reach an accuracy of tens of micro arcseconds, it is able to perform the mostprecise astrometric measurement of SgrA* to date. For that purpose, GRAVITY combinesthe light collected (coherently) from of all the 8 m UTs or the four 1.8 m ATs providing in-frared wavefront sensing to control the telescope adaptive optics, two interferometric beamcombiners (one for fringe-tracking and one for the science object), an acquisition cameraand various laser guiding systems for beam stabilization, as well as a dedicated laser metrol-ogy to trace the optical path length differences for narrow angle astrometry. Operating inK band with an active stabilization of the science channel, GRAVITY is able to increasethe typical integration time from a few milliseconds (the typical atmospheric coherencetime) to minutes, which implies a big leap in sensitivity allowing to observe fainter objects(K=19 in science detector) with the power of a 130m baseline interferometer, as it is theclose environment of the supermassive black hole located in the center of our Galaxy.
Published: 2018

25. First direct detection of an exoplanet by optical interferometry Astrometry and K-band spectroscopy of HR 8799 e

Author: Lacour, S., Nowak, M., Wang, J., Pfuhl, O., Eisenhauer, F., Abuter, R., Amorim, A., Anugu, N., Benisty, M., Berger, J. P., Beust, H., Blind, N., Bonnefoy, M., Bonnet, H., Bourget, P., Brandner, W., Buron, A., Collin, C., Charnay, B., Chapron, F., Clenet, Y., Coude du Foresto, V, de Zeeuw, P. T., Deen, C., Dembet, R., Dexter, J., Duvert, G., Eckart, A., Forster Schreiber, N. M., Fedou, P., Garcia, P., Garcia Lopez, R., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Gordo, P., Greenbaum, A., Habibi, M., Haubois, X., Haussmann, F., Henning, Th, Hippler, S., Horrobin, M., Hubert, Z., Jimenez Rosales, A., Jocou, L., Kendrew, S., Kervella, P., Kolb, J., Lagrange, A-M, Lapeyrere, V, Le Bouquin, J-B, Lena, P., Lippa, M., Lenzen, R., Maire, A-L, Molliere, P., Ott, T., Paumard, T., Perraut, K., Perrin, G., Pueyo, L., Rabien, S., Ramirez, A., Rau, C., Rodriguez-Coira, G., Rousset, G., Sanchez-Bermudez, J., Scheithauer, S., Schuhler, N., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., Vincent, F., van Dishoeck, E. F., von Fellenberg, S., Wank, I, Waisberg, I, Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Woillez, J., Yazici, S., Ziegler, D., Zins, G., Lacour, S., Nowak, M., Wang, J., Pfuhl, O., Eisenhauer, F., Abuter, R., Amorim, A., Anugu, N., Benisty, M., Berger, J. P., Beust, H., Blind, N., Bonnefoy, M., Bonnet, H., Bourget, P., Brandner, W., Buron, A., Collin, C., Charnay, B., Chapron, F., Clenet, Y., Coude du Foresto, V, de Zeeuw, P. T., Deen, C., Dembet, R., Dexter, J., Duvert, G., Eckart, A., Forster Schreiber, N. M., Fedou, P., Garcia, P., Garcia Lopez, R., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Gordo, P., Greenbaum, A., Habibi, M., Haubois, X., Haussmann, F., Henning, Th, Hippler, S., Horrobin, M., Hubert, Z., Jimenez Rosales, A., Jocou, L., Kendrew, S., Kervella, P., Kolb, J., Lagrange, A-M, Lapeyrere, V, Le Bouquin, J-B, Lena, P., Lippa, M., Lenzen, R., Maire, A-L, Molliere, P., Ott, T., Paumard, T., Perraut, K., Perrin, G., Pueyo, L., Rabien, S., Ramirez, A., Rau, C., Rodriguez-Coira, G., Rousset, G., Sanchez-Bermudez, J., Scheithauer, S., Schuhler, N., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., Vincent, F., van Dishoeck, E. F., von Fellenberg, S., Wank, I, Waisberg, I, Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Woillez, J., Yazici, S., Ziegler, D., and Zins, G.
Abstract: Aims. 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 of high contrast observations, enabling the direct observation of exoplanets. We demonstrate the technique on HR 8799, a young planetary system composed of four known giant exoplanets. Methods. We used the GRAVITY fringe tracker to lock the fringes on the central star, and integrated off-axis on the HR 8799 e planet situated at 390 mas from the star. Data reduction included post-processing to remove the flux leaking from the central star and to extract the coherent flux of the planet. The inferred K band spectrum of the planet has a spectral resolution of 500. We also derive the astrometric position of the planet relative to the star with a precision on the order of 100 mu as. Results. The GRAVITY astrometric measurement disfavors perfectly coplanar stable orbital solutions. A small adjustment of a few degrees to the orbital inclination of HR 8799 e can resolve the tension, implying that the orbits are close to, but not strictly coplanar. The spectrum, with a signal-to-noise ratio of approximate to 5 per spectral channel, is compatible with a late- type L brown dwarf. Using Exo-REM synthetic spectra, we derive a temperature of 1150 +/- 50 K and a surface gravity of 10(4.3 +/- 0.3) cm s(2). This corresponds to a radius of 1.17(-0.11)(+0.13) R-Jup and a mass of 10(-4)(+7) M-Jup, which is an independent confirmation of mass estimates from evolutionary models. Our results demonstrate the power of interferometry for the direct detection and spectroscopic study of exoplanets at close angular separations from their stars.
Published: 2019

26. GRAVITY chromatic imaging of η Car's core. Milliarcsecond resolution imaging of the wind-wind collision zone (Brγ, He I)

Author: Collaboration, G., Sanchez-Bermudez, J., Weigelt, G., Bestenlehner, J., Kervella, P., Brandner, W., Henning, T., Müller, A., Perrin, G., Pott, J., Schöller, M., van Boekel, R., Abuter, R., Accardo, M., Amorim, A., Anugu, N., Ávila, G., Benisty, M., Berger, J., Blind, N., Bonnet, H., Bourget, P., Brast, R., Buron, A., Cantalloube, F., Caratti O Garatti, A., Cassaing, F., Chapron, F., Choquet, E., Clénet, Y., Collin, C., Coudé Du Foresto, V., de Wit, W., de Zeeuw, T., Deen, C., Delplancke-Ströbele, F., Dembet, R., Derie, F., Dexter, J., Duvert, G., Ebert, M., Eckart, A., Eisenhauer, F., Esselborn, M., Fédou, P., Garcia, P., Garcia Dabo, C., Garcia Lopez, R., Gao, F., Gendron, E., Genzel, R., Gillessen, S., Haubois, X., Haug, M., Haussmann, F., Hippler, S., Horrobin, M., Huber, A., Hubert, Z., Hubin, N., Hummel, C., Jakob, G., Jochum, L., Jocou, L., Karl, M., Kaufer, A., Kellner, S., Kendrew, S., Kern, L., Kiekebusch, M., Klein, R., Kolb, J., Kulas, M., Lacour, S., Lapeyrère, V., Lazareff, B., Le Bouquin, J., Léna, P., Lenzen, R., Lévêque, S., Lippa, M., Magnard, Y., Mehrgan, L., Mellein, M., Mérand, A., Moreno-Ventas, J., Moulin, T., Müller, E., Müller, F., Neumann, U., Oberti, S., Ott, T., Pallanca, L., Panduro, J., Pasquini, L., Paumard, T., Percheron, I., Perraut, K., Petrucci, P., Pflüger, A., Pfuhl, O., Duc, T., Plewa, P., Popovic, D., Rabien, S., Ramirez, A., Ramos, J., Rau, C., Riquelme, M., Rodríguez-Coira, G., Rohloff, R., Rosales, A., Rousset, G., Scheithauer, S., Schuhler, N., Spyromilio, J., Straub, O., Straubmeier, C., Sturm, E., Suarez, M., Tristram, K., Ventura, N., Vincent, F., Waisberg, I., Wank, I., Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Wittkowski, M., Woillez, J., Wolff, B., Yazici, S., Ziegler, D., and Zins, G.
Subjects: Astrophysics::Solar and Stellar Astrophysics
Abstract: Context. η Car is one of the most intriguing luminous blue variables in the Galaxy. Observations and models of the X-ray, ultraviolet, optical, and infrared emission suggest a central binary in a highly eccentric orbit with a 5.54 yr period residing in its core. 2D and 3D radiative transfer and hydrodynamic simulations predict a primary with a dense and slow stellar wind that interacts with the faster and lower density wind of the secondary. The wind-wind collision scenario suggests that the secondary's wind penetrates the primary's wind creating a low-density cavity in it, with dense walls where the two winds interact. However, the morphology of the cavity and its physical properties are not yet fully constrained. Aims: We aim to trace the inner ̃5-50 au structure of η Car's wind-wind interaction, as seen through Brγ and, for the first time, through the He I 2s-2p line. Methods: We have used spectro-interferometric observations with the K-band beam-combiner GRAVITY at the VLTI. The analyses of the data include (i) parametrical model-fitting to the interferometric observables, (ii) a CMFGEN model of the source's spectrum, and (iii) interferometric image reconstruction. Results: Our geometrical modeling of the continuum data allows us to estimate its FWHM angular size close to 2 mas and an elongation ratio ∊ = 1.06 ± 0.05 over a PA = 130° ± 20°. Our CMFGEN modeling of the spectrum helped us to confirm that the role of the secondary should be taken into account to properly reproduce the observed Brγ and He I lines. Chromatic images across the Brγ line reveal a southeast arc-like feature, possibly associated to the hot post-shocked winds flowing along the cavity wall. The images of the He I 2s-2p line served to constrain the 20 mas (̃50 au) structure of the line-emitting region. The observed morphology of He I suggests that the secondary is responsible for the ionized material that produces the line profile. Both the Brγ and the He I 2s-2p maps are consistent with previous hydrodynamical models of the colliding wind scenario. Future dedicated simulations together with an extensive interferometric campaign are necessary to refine our constraints on the wind and stellar parameters of the binary, which finally will help us predict the evolutionary path of η Car.
Published: 2018

27. Multiple star systems in the Orion nebula

Author: Collaboration, G., Karl, M., Pfuhl, O., Eisenhauer, F., Genzel, R., Grellmann, R., Habibi, M., Abuter, R., Accardo, M., Amorim, A., Anugu, N., Ávila, G., Benisty, M., Berger, J., Blind, N., Bonnet, H., Bourget, P., Brandner, W., Brast, R., Buron, A., Caratti O Garatti, A., Chapron, F., Clénet, Y., Collin, C., Coudé Du Foresto, V., de Wit, W., de Zeeuw, T., Deen, C., Delplancke-Ströbele, F., Dembet, R., Derie, F., Dexter, J., Duvert, G., Ebert, M., Eckart, A., Esselborn, M., Fédou, P., Finger, G., Garcia, P., Garcia Dabo, C., Garcia Lopez, R., Gao, F., Gendron, É., Gillessen, S., Gonté, F., Gordo, P., Grözinger, U., Guajardo, P., Guieu, S., Haguenauer, P., Hans, O., Haubois, X., Haug, M., Haußmann, F., Henning, T., Hippler, S., Horrobin, M., Huber, A., Hubert, Z., Hubin, N., Jakob, G., Jochum, L., Jocou, L., Kaufer, A., Kellner, S., Kendrew, S., Kern, L., Kervella, P., Kiekebusch, M., Klein, R., Köhler, R., Kolb, J., Kulas, M., Lacour, S., Lapeyrère, V., Lazareff, B., Le Bouquin, J., Léna, P., Lenzen, R., Lévêque, S., Lin, C., Lippa, M., Magnard, Y., Mehrgan, L., Mérand, A., Moulin, T., Müller, E., Müller, F., Neumann, U., Oberti, S., Ott, T., Pallanca, L., Panduro, J., Pasquini, L., Paumard, T., Percheron, I., Perraut, K., Perrin, G., Pflüger, A., Duc, T., Plewa, P., Popovic, D., Rabien, S., Ramírez, A., Ramos, J., Rau, C., Riquelme, M., Rodríguez-Coira, G., Rohloff, R., Rosales, A., Rousset, G., Sanchez-Bermudez, J., Scheithauer, S., Schöller, M., Schuhler, N., Spyromilio, J., Straub, O., Straubmeier, C., Sturm, E., Suarez, M., Tristram, K., Ventura, N., Vincent, F., Waisberg, I., Wank, I., Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Wittkowski, M., Woillez, J., Wolff, B., Yazici, S., Ziegler, D., and Zins, G.
Abstract: This work presents an interferometric study of the massive-binary fraction in the Orion Trapezium cluster with the recently comissioned GRAVITY instrument. We observed a total of 16 stars of mainly OB spectral type. We find three previously unknown companions for θ1 Ori B, θ2 Ori B, and θ2 Ori C. We determined a separation for the previously suspected companion of NU Ori. We confirm four companions for θ1 Ori A, θ1 Ori C, θ1 Ori D, and θ2 Ori A, all with substantially improved astrometry and photometric mass estimates. We refined the orbit of the eccentric high-mass binary θ1 Ori C and we are able to derive a new orbit for θ1 Ori D. We find a system mass of 21.7 M☉ and a period of 53 days. Together with other previously detected companions seen in spectroscopy or direct imaging, eleven of the 16 high-mass stars are multiple systems. We obtain a total number of 22 companions with separations up to 600 AU. The companion fraction of the early B and O stars in our sample is about two, significantly higher than in earlier studies of mostly OB associations. The separation distribution hints toward a bimodality. Such a bimodality has been previously found in A stars, but rarely in OB binaries, which up to this point have been assumed to be mostly compact with a tail of wider companions. We also do not find a substantial population of equal-mass binaries. The observed distribution of mass ratios declines steeply with mass, and like the direct star counts, indicates that our companions follow a standard power law initial mass function. Again, this is in contrast to earlier findings of flat mass ratio distributions in OB associations. We excluded collision as a dominant formation mechanism but find no clear preference for core accretion or competitive accretion.
Published: 2018

28. Detection of the gravitational redshift in the orbit of the star S2 near the Galactic centre massive black hole

Author: Abuter, R., Amorim, A., Anugu, N., Bauboeck, M., Benisty, M., Berger, J. P., Blind, N., Bonnet, H., Brandner, W., Buron, A., Collin, C., Chapron, F., Clenet, Y., du Foresto, V. Coude, de Zeeuw, P. T., Deen, C., Delplancke-Stroebele, F., Dembet, R., Dexter, J., Duvert, G., Eckart, A., Eisenhauer, F., Finger, G., Schreiber, N. M. Foerster, Fedou, P., Garcia, P., Lopez, R. Garcia, Gao, F., Gendron, E., Genzel, R., Gillessen, S., Gordo, P., Habibi, M., Haubois, X., Haug, M., Haussmann, F., Henning, Th, Hippler, S., Horrobin, M., Hubert, Z., Hubin, N., Rosales, A. Jimenez, Jochum, L., Jocou, L., Kaufer, A., Kellner, S., Kendrew, S., Kervella, P., Kok, Y., Kulas, M., Lacour, S., Lapeyrere, V, Lazareff, B., Le Bouquin, J-B, Lena, P., Lippa, M., Lenzen, R., Merand, A., Mueller, E., Neumann, U., Ott, T., Palanca, L., Paumard, T., Pasquini, L., Perraut, K., Perrin, G., Pfuhl, O., Plewa, P. M., Rabien, S., Ramirez, A., Ramos, J., Rau, C., Rodriguez-Coira, G., Rohloff, R-R, Rousset, G., Sanchez-Bermudez, J., Scheithauer, S., Schoeller, M., Schuler, N., Spyromilio, J., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., Tristram, K. R. W., Vincent, F., von Fellenberg, S., Wank, I, Waisberg, I, Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Woillez, J., Yazici, S., Ziegler, D., Zins, G., Abuter, R., Amorim, A., Anugu, N., Bauboeck, M., Benisty, M., Berger, J. P., Blind, N., Bonnet, H., Brandner, W., Buron, A., Collin, C., Chapron, F., Clenet, Y., du Foresto, V. Coude, de Zeeuw, P. T., Deen, C., Delplancke-Stroebele, F., Dembet, R., Dexter, J., Duvert, G., Eckart, A., Eisenhauer, F., Finger, G., Schreiber, N. M. Foerster, Fedou, P., Garcia, P., Lopez, R. Garcia, Gao, F., Gendron, E., Genzel, R., Gillessen, S., Gordo, P., Habibi, M., Haubois, X., Haug, M., Haussmann, F., Henning, Th, Hippler, S., Horrobin, M., Hubert, Z., Hubin, N., Rosales, A. Jimenez, Jochum, L., Jocou, L., Kaufer, A., Kellner, S., Kendrew, S., Kervella, P., Kok, Y., Kulas, M., Lacour, S., Lapeyrere, V, Lazareff, B., Le Bouquin, J-B, Lena, P., Lippa, M., Lenzen, R., Merand, A., Mueller, E., Neumann, U., Ott, T., Palanca, L., Paumard, T., Pasquini, L., Perraut, K., Perrin, G., Pfuhl, O., Plewa, P. M., Rabien, S., Ramirez, A., Ramos, J., Rau, C., Rodriguez-Coira, G., Rohloff, R-R, Rousset, G., Sanchez-Bermudez, J., Scheithauer, S., Schoeller, M., Schuler, N., Spyromilio, J., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., Tristram, K. R. W., Vincent, F., von Fellenberg, S., Wank, I, Waisberg, I, Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Woillez, J., Yazici, S., Ziegler, D., and Zins, G.
Abstract: 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. Near pericentre at 120 AU approximate to 1400 Schwarzschild radii, the star has an orbital speed of approximate to 7650 km s(-1), such that the first-order effects of Special and General Relativity have now become detectable with current capabilities. Over the past 26 years, we have monitored the radial velocity and motion on the sky of S2, mainly with the SINFONI and NACO adaptive optics instruments on the ESO Very Large Telescope, and since 2016 and leading up to the pericentre approach in May 2018, with the four-telescope interferometric beam-combiner instrument GRAVITY. From data up to and including pericentre, we robustly detect the combined gravitational redshift and relativistic transverse Doppler effect for S2 of z = Delta lambda/lambda approximate to 200 km s(-1)/c with different statistical analysis methods. When parameterising the post-Newtonian contribution from these effects by a factor f, with f = 0 and f = 1 corresponding to the Newtonian and general relativistic limits, respectively, we find from posterior fitting with different weighting schemes f = 0.90 +/- 0.09 vertical bar(stat) +/- 0.151 vertical bar(sys). The S2 data are inconsistent with pure Newtonian dynamics.
Published: 2018

29. GRAVITY chromatic imaging of eta Car's core Milliarcsecond resolution imaging of the wind-wind collision zone (Br gamma, He i)

Author: Sanchez-Bermudez, J., Weigelt, G., Bestenlehner, J. M., Kervella, P., Brandner, W., Henning, Th, Mueller, A., Perrin, G., Pott, J-U, Schoeller, M., van Boeke, R., Abuter, R., Accardo, M., Amorim, A., Anugu, N., Avila, G., Benisty, M., Berger, J. P., Blind, N., Bonnet, H., Bourget, P., Brast, R., Buron, A., Cantalloube, F., Garatti, A. Caratti O., Cassaing, F., Chapron, F., Choquet, E., Clenet, Y., Collin, C., du Foresto, V. Coude, de Wit, W., de Zeeuw, T., Deen, C., Delplancke-Stroebele, F., Dembet, R., Derie, F., Dexter, J., Duvert, G., Ebert, M., Eckart, A., Eisenhauer, F., Esselborn, M., Fedou, P., Garcia, P. J., V, Dabo, C. E. Garcia, Lopez, R. Garcia, Gao, F., Gendron, E., Genzel, R., Gillessen, S., Haubois, X., Haug, M., Haussmann, F., Hippler, S., Horrobin, M., Huber, A., Hubert, Z., Hubin, N., Hummel, C. A., Jakob, G., Jochum, L., Jocou, L., Karl, M., Kaufer, A., Kellner, S., Kendrew, S., Kern, L., Kiekebusch, M., Klein, R., Kolb, J., Kulas, M., Lacour, S., Lapeyrere, V, Lazareff, B., Le Bouquin, J-B, Lena, P., Lenzen, R., Leveque, S., Lippa, M., Magnard, Y., Mehrgan, L., Mellein, M., Merand, A., Moreno-Ventas, J., Moulin, T., Mueller, E., Mueller, F., Neumann, U., Oberti, S., Ott, T., Pallanca, L., Panduro, J., Pasquini, L., Paumard, T., Percheron, I, Perraut, K., Petrucci, P-O, Pflueger, A., Pfuhl, O., Duc, T. P., Plewa, P. M., Popovic, D., Rabien, S., Ramirez, A., Ramos, J., Rau, C., Riquelme, M., Rodriguez-Coira, G., Rohloff, R-R, Rosales, A., Rousset, G., Scheithauer, S., Schuhler, N., Spyromilio, J., Straub, O., Straubmeier, C., Sturm, E., Suarez, M., Tristram, K. R. W., Ventura, N., Vincent, F., Waisberg, I, Wank, I, Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Wittkowski, M., Woillez, J., Wolff, B., Yazici, S., Ziegler, D., Zins, G., Sanchez-Bermudez, J., Weigelt, G., Bestenlehner, J. M., Kervella, P., Brandner, W., Henning, Th, Mueller, A., Perrin, G., Pott, J-U, Schoeller, M., van Boeke, R., Abuter, R., Accardo, M., Amorim, A., Anugu, N., Avila, G., Benisty, M., Berger, J. P., Blind, N., Bonnet, H., Bourget, P., Brast, R., Buron, A., Cantalloube, F., Garatti, A. Caratti O., Cassaing, F., Chapron, F., Choquet, E., Clenet, Y., Collin, C., du Foresto, V. Coude, de Wit, W., de Zeeuw, T., Deen, C., Delplancke-Stroebele, F., Dembet, R., Derie, F., Dexter, J., Duvert, G., Ebert, M., Eckart, A., Eisenhauer, F., Esselborn, M., Fedou, P., Garcia, P. J., V, Dabo, C. E. Garcia, Lopez, R. Garcia, Gao, F., Gendron, E., Genzel, R., Gillessen, S., Haubois, X., Haug, M., Haussmann, F., Hippler, S., Horrobin, M., Huber, A., Hubert, Z., Hubin, N., Hummel, C. A., Jakob, G., Jochum, L., Jocou, L., Karl, M., Kaufer, A., Kellner, S., Kendrew, S., Kern, L., Kiekebusch, M., Klein, R., Kolb, J., Kulas, M., Lacour, S., Lapeyrere, V, Lazareff, B., Le Bouquin, J-B, Lena, P., Lenzen, R., Leveque, S., Lippa, M., Magnard, Y., Mehrgan, L., Mellein, M., Merand, A., Moreno-Ventas, J., Moulin, T., Mueller, E., Mueller, F., Neumann, U., Oberti, S., Ott, T., Pallanca, L., Panduro, J., Pasquini, L., Paumard, T., Percheron, I, Perraut, K., Petrucci, P-O, Pflueger, A., Pfuhl, O., Duc, T. P., Plewa, P. M., Popovic, D., Rabien, S., Ramirez, A., Ramos, J., Rau, C., Riquelme, M., Rodriguez-Coira, G., Rohloff, R-R, Rosales, A., Rousset, G., Scheithauer, S., Schuhler, N., Spyromilio, J., Straub, O., Straubmeier, C., Sturm, E., Suarez, M., Tristram, K. R. W., Ventura, N., Vincent, F., Waisberg, I, Wank, I, Widmann, F., Wieprecht, E., Wiest, M., Wiezorrek, E., Wittkowski, M., Woillez, J., Wolff, B., Yazici, S., Ziegler, D., and Zins, G.
Abstract: Context. eta Car is one of the most intriguing luminous blue variables in the Galaxy. Observations and models of the X-ray, ultraviolet, optical, and infrared emission suggest a central binary in a highly eccentric orbit with a 5.54 yr period residing in its core. 2D and 3D radiative transfer and hydrodynamic simulations predict a primary with a dense and slow stellar wind that interacts with the faster and lower density wind of the secondary. The wind-wind collision scenario suggests that the secondary's wind penetrates the primary's wind creating a low-density cavity in it, with dense walls where the two winds interact. However, the morphology of the cavity and its physical properties are not yet fully constrained. Aims. We aim to trace the inner similar to 5-50 au structure of eta Car's wind-wind interaction, as seen through Br gamma and, for the first time, through the He i 2s-2p line. Methods. We have used spectro-interferometric observations with the K-band beam-combiner GRAVITY at the VLTI. The analyses of the data include (i) parametrical model-fitting to the interferometric observables, (ii) a CMFGEN model of the source's spectrum, and (iii) interferometric image reconstruction. Results. Our geometrical modeling of the continuum data allows us to estimate its FWHM angular size close to 2 mas and an elongation ratio epsilon = 1.06 +/- 0.05 over a PA = 130 degrees +/- 20 degrees. Our CMFGEN modeling of the spectrum helped us to confirm that the role of the secondary should be taken into account to properly reproduce the observed Br gamma and He i lines. Chromatic images across the Br gamma line reveal a southeast arc-like feature, possibly associated to the hot post-shocked winds flowing along the cavity wall. The images of the He i 2s-2p line served to constrain the 20 mas (similar to 50 au) structure of the line-emitting region. The observed morphology of He i suggests that the secondary is responsible for the ionized material that produces the line profile
Published: 2018

30. First light for GRAVITY: Phase referencing optical interferometry for the Very Large Telescope Interferometer

Author: Abuter, R., Accardo, M., Amorim, A., Anugu, N., Avila, G., Azouaoui, N., Benisty, M., Berger, J. P., Blind, N., Bonnet, H., Bourget, P., Brandner, W., Brast, R., Buron, A., Burtscher, L., Cassaing, F., Chapron, F., Choquet, E., Clenet, Y., Collin, C., du Foresto, V. Coude, de Wit, W., de Zeeuw, P. T., Deen, C., Delplancke-Stroebele, F., Dembet, R., Derie, F., Dexter, J., Duvert, G., Ebert, M., Eckart, A., Eisenhauer, F., Esselborn, M., Fedou, P., Finger, G., Garcia, P., Dabo, C. E. Garcia, Lopez, R. Garcia, Gendron, E., Genzel, R., Gillessen, S., Gonte, F., Gordo, P., Grould, M., Groezinger, U., Guieu, S., Haguenauer, P., Hans, O., Haubois, X., Haug, M., Haussmann, F., Henning, Th., Hippler, S., Horrobin, M., Huber, A., Hubert, Z., Hubin, N., Hummel, C. A., Jakob, G., Janssen, A., Jochum, L., Jocou, L., Kaufer, A., Kellner, S., Kendrew, S., Kern, L., Kervella, P., Kiekebusch, M., Klein, R., Kok, Y., Kolb, J., Kulas, M., Lacour, S., Lapeyrere, V., Lazareff, B., Le Bouquin, J. -B., Lena, P., Lenzen, R., Leveque, S., Lippa, M., Magnard, Y., Mehrgan, L., Mellein, M., Merand, A., Moreno-Ventas, J., Moulin, T., Mueller, E., Mueller, F., Neumann, U., Oberti, S., Ott, T., Pallanca, L., Panduro, J., Pasquini, L., Paumard, T., Percheron, I., Perraut, K., Perrin, G., Pflueger, A., Pfuhl, O., Duc, T. Phan, Plewa, P. M., Popovic, D., Rabien, S., Ramirez, A., Ramos, J., Rau, C., Riquelme, M., Rohloff, R. -R., Rousset, G., Sanchez-Bermudez, J., Scheithauer, S., Schoeller, M., Schuhler, N., Spyromilio, J., Straubmeier, C., Sturm, E., Suarez, M., Tristram, K. R. W., Ventura, N., Vincent, F., Waisberg, I., Wank, I., Weber, J., Wieprecht, E., Wiest, M., Wiezorrek, E., Wittkowski, M., Woillez, J., Wolff, B., Yazici, S., Ziegler, D., Zins, G., Abuter, R., Accardo, M., Amorim, A., Anugu, N., Avila, G., Azouaoui, N., Benisty, M., Berger, J. P., Blind, N., Bonnet, H., Bourget, P., Brandner, W., Brast, R., Buron, A., Burtscher, L., Cassaing, F., Chapron, F., Choquet, E., Clenet, Y., Collin, C., du Foresto, V. Coude, de Wit, W., de Zeeuw, P. T., Deen, C., Delplancke-Stroebele, F., Dembet, R., Derie, F., Dexter, J., Duvert, G., Ebert, M., Eckart, A., Eisenhauer, F., Esselborn, M., Fedou, P., Finger, G., Garcia, P., Dabo, C. E. Garcia, Lopez, R. Garcia, Gendron, E., Genzel, R., Gillessen, S., Gonte, F., Gordo, P., Grould, M., Groezinger, U., Guieu, S., Haguenauer, P., Hans, O., Haubois, X., Haug, M., Haussmann, F., Henning, Th., Hippler, S., Horrobin, M., Huber, A., Hubert, Z., Hubin, N., Hummel, C. A., Jakob, G., Janssen, A., Jochum, L., Jocou, L., Kaufer, A., Kellner, S., Kendrew, S., Kern, L., Kervella, P., Kiekebusch, M., Klein, R., Kok, Y., Kolb, J., Kulas, M., Lacour, S., Lapeyrere, V., Lazareff, B., Le Bouquin, J. -B., Lena, P., Lenzen, R., Leveque, S., Lippa, M., Magnard, Y., Mehrgan, L., Mellein, M., Merand, A., Moreno-Ventas, J., Moulin, T., Mueller, E., Mueller, F., Neumann, U., Oberti, S., Ott, T., Pallanca, L., Panduro, J., Pasquini, L., Paumard, T., Percheron, I., Perraut, K., Perrin, G., Pflueger, A., Pfuhl, O., Duc, T. Phan, Plewa, P. M., Popovic, D., Rabien, S., Ramirez, A., Ramos, J., Rau, C., Riquelme, M., Rohloff, R. -R., Rousset, G., Sanchez-Bermudez, J., Scheithauer, S., Schoeller, M., Schuhler, N., Spyromilio, J., Straubmeier, C., Sturm, E., Suarez, M., Tristram, K. R. W., Ventura, N., Vincent, F., Waisberg, I., Wank, I., Weber, J., Wieprecht, E., Wiest, M., Wiezorrek, E., Wittkowski, M., Woillez, J., Wolff, B., Yazici, S., Ziegler, D., and Zins, G.
Abstract: 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 130m diameter angular resolution and a collecting area of 200 m(2). The instrument comprises fiber fed integrated optics beam combination, high resolution spectroscopy, built-in beam analysis and control, near-infrared wavefront sensing, phase-tracking, dual-beam operation, and laser metrology. GRAVITY opens up to optical/infrared interferometry the techniques of phase referenced imaging and narrow angle astrometry, in many aspects following the concepts of radio interferometry. This article gives an overview of GRAVITY and reports on the performance and the first astronomical observations during commissioning in 2015/16. We demonstrate phase-tracking on stars as faint as m(K) approximate to 10 mag, phase-referenced interferometry of objects fainter than m(K) approximate to 15 mag with a limiting magnitude of m(K) approximate to 17 mag, minute long coherent integrations, a visibility accuracy of better than 0.25%, and spectro-differential phase and closure phase accuracy better than 0.5 degrees, corresponding to a differential astrometric precision of better than ten microarcseconds (as). The dual-beam astrometry, measuring the phase difference of two objects with laser metrology, is still under commissioning. First observations show residuals as low as 50 mu as when following objects over several months. We illustrate the instrument performance with the observations of archetypical objects for the different instrument modes. Examples include the Galactic center supermassive black hole and its fast orbiting star S2 for phase referenced dual-beam observations and infrared wavefront sensing, the high mass X-ray binary BP Cru and the active galactic nucleus of PDS 456 for a few mu as spectro-differential astrometry, the T Tauri star S CrA for a spectro-differential visibility analysis, xi Tel and 24
Published: 2017

31. Accretion-ejection morphology of the microquasar SS 433 resolved at sub-au scale

Author: Petrucci, P. -O., Waisberg, I., Le Bouquin, J. -B., Dexter, J., Dubus, G., Perraut, K., Kervella, P., Abuter, R., Amorim, A., Anugu, N., Berger, J. P., Blind, N., Bonnet, H., Brandner, W., Buron, A., Choquet, E., Clenet, Y., de Wit, W., Deen, C., Eckart, A., Eisenhauer, F., Finger, G., Garcia, P., Lopez, R. Garcia, Gendron, E., Genzel, R., Gillessen, S., Gonte, F., Haubois, X., Haug, M., Haussmann, F., Henning, Th., Hippler, S., Horrobin, M., Hubert, Z., Jochum, L., Jocou, L., Kok, Y., Kolb, J., Kulas, M., Lacour, S., Lazareff, B., Lena, P., Lippa, M., Merand, A., Mueller, E., Ott, T., Panduro, J., Paumard, T., Perrin, G., Pfuhl, O., Ramos, J., Rau, C., Rohlo, R. -R., Rousset, G., Sanchez-Bermudez, J., Scheithauer, S., Schoeller, M., Straubmeier, C., Sturm, E., Vincent, F., Wank, I., Wieprecht, E., Wiest, M., Wiezorrek, E., Wittkowski, M., Woillez, J., Yazici, S., Zins, G., Petrucci, P. -O., Waisberg, I., Le Bouquin, J. -B., Dexter, J., Dubus, G., Perraut, K., Kervella, P., Abuter, R., Amorim, A., Anugu, N., Berger, J. P., Blind, N., Bonnet, H., Brandner, W., Buron, A., Choquet, E., Clenet, Y., de Wit, W., Deen, C., Eckart, A., Eisenhauer, F., Finger, G., Garcia, P., Lopez, R. Garcia, Gendron, E., Genzel, R., Gillessen, S., Gonte, F., Haubois, X., Haug, M., Haussmann, F., Henning, Th., Hippler, S., Horrobin, M., Hubert, Z., Jochum, L., Jocou, L., Kok, Y., Kolb, J., Kulas, M., Lacour, S., Lazareff, B., Lena, P., Lippa, M., Merand, A., Mueller, E., Ott, T., Panduro, J., Paumard, T., Perrin, G., Pfuhl, O., Ramos, J., Rau, C., Rohlo, R. -R., Rousset, G., Sanchez-Bermudez, J., Scheithauer, S., Schoeller, M., Straubmeier, C., Sturm, E., Vincent, F., Wank, I., Wieprecht, E., Wiest, M., Wiezorrek, E., Wittkowski, M., Woillez, J., Yazici, S., and Zins, G.
Abstract: We present the first optical observation of the microquasar SS 433 at sub-milliarcsecond (mas) scale obtained with the GRAVITY instrument on the Very Large Telescope interferometer (VLTI). The 3.5-h exposure reveals a rich K-band spectrum dominated by hydrogen Br gamma and He i lines, as well as (red-shifted) emission lines coming from the jets. The K-band-continuum-emitting region is dominated by a marginally resolved point source (<1 mas) embedded inside a diffuse background accounting for 10% of the total flux. The jet line positions agree well with the ones expected from the jet kinematic model, an interpretation also supported by the consistent sign (i.e., negative/positive for the receding/approaching jet component) of the phase shifts observed in the lines. The significant visibility drop across the jet lines, together with the small and nearly identical phases for all baselines, point toward a jet that is off set by less than 0.5 mas from the continuum source and resolved in the direction of propagation, with a typical size of 2 mas. The jet position angle of similar to 80 degrees is consistent with the expected one at the observation date. Jet emission so close to the central binary system would suggest that line locking, if relevant to explain the amplitude and stability of the 0.26c jet velocity, operates on elements heavier than hydrogen. The Br gamma profile is broad and double peaked. It is better resolved than the continuum and the change of the phase signal sign across the line on all baselines suggests an East-West-oriented geometry similar to the jet direction and supporting a (polar) disk wind origin.
Published: 2017

32. Submilliarcsecond Optical Interferometry of the High-mass X-Ray Binary BP Cru with VLTI/GRAVITY

Author: Waisberg, I., Dexter, J., Pfuhl, O., Abuter, R., Amorim, A., Anugu, N., Berger, J. P., Blind, N., Bonnet, H., Brandner, W., Buron, A., Clenet, Y., de Wit, W., Deen, C., Delplancke-Strobele, F., Dembet, R., Duvert, G., Eckart, A., Eisenhauer, F., Fedou, P., Finger, G., Garcia, P., Lopez, R. Garcia, Gendron, E., Genzel, R., Gillessen, S., Haubois, X., Haug, M., Haussmann, F., Henning, Th., Hippler, S., Horrobin, M., Hubert, Z., Jochum, L., Jocou, L., Kervella, P., Kok, Y., Kulas, M., Lacour, S., Lapeyrere, V., Le Bouquin, J. -B., Lena, P., Lippa, M., Merand, A., Muller, E., Ott, T., Pallanca, L., Panduro, J., Paumard, T., Perraut, K., Perrin, G., Rabien, S., Ramirez, A., Ramos, J., Rau, C., Rohloff, R. -R., Rousset, G., Sanchez-Bermudez, J., Scheithauer, S., Scholler, M., Straubmeier, C., Sturm, E., Vincent, F., Wank, I., Wieprecht, E., Wiest, M., Wiezorrek, E., Wittkowski, M., Woillez, J., Yazici, S., Waisberg, I., Dexter, J., Pfuhl, O., Abuter, R., Amorim, A., Anugu, N., Berger, J. P., Blind, N., Bonnet, H., Brandner, W., Buron, A., Clenet, Y., de Wit, W., Deen, C., Delplancke-Strobele, F., Dembet, R., Duvert, G., Eckart, A., Eisenhauer, F., Fedou, P., Finger, G., Garcia, P., Lopez, R. Garcia, Gendron, E., Genzel, R., Gillessen, S., Haubois, X., Haug, M., Haussmann, F., Henning, Th., Hippler, S., Horrobin, M., Hubert, Z., Jochum, L., Jocou, L., Kervella, P., Kok, Y., Kulas, M., Lacour, S., Lapeyrere, V., Le Bouquin, J. -B., Lena, P., Lippa, M., Merand, A., Muller, E., Ott, T., Pallanca, L., Panduro, J., Paumard, T., Perraut, K., Perrin, G., Rabien, S., Ramirez, A., Ramos, J., Rau, C., Rohloff, R. -R., Rousset, G., Sanchez-Bermudez, J., Scheithauer, S., Scholler, M., Straubmeier, C., Sturm, E., Vincent, F., Wank, I., Wieprecht, E., Wiest, M., Wiezorrek, E., Wittkowski, M., Woillez, J., and Yazici, S.
Abstract: We observe the high-mass X-ray binary (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 size of the hypergiant. Differential visibility amplitude (Delta|V| similar to 5%) and phase (Delta phi similar to 2 degrees) signatures are observed across the He I 2.059 mu m and Br gamma lines, the latter seen strongly in emission, unusual for the donor star's spectral type. For a baseline B similar to 100 m, the differential phase rms similar to 0 degrees 2 corresponds to an astrometric precision of similar to 2 mu as. We generalize expressions for image centroid displacements and variances in the marginally resolved limit of interferometry to spectrally resolved data, and use them to derive model-independent properties of the emission such as its asymmetry, extension, and strong wavelength dependence. We propose geometric models based on an extended and distorted wind and/or a high-density gas stream, which has long been predicted to be present in this system. The observations show that optical interferometry is now able to resolve HMXBs at the spatial scale where accretion takes place, and therefore to probe the effects of the gravitational and radiation fields of the compact object on its environment.
Published: 2017

33. Functional and performance tests of the fringe and flexure tracking system for LINC-NIRVANA

Author: Rauch, C., primary, Eckart, A., additional, Horrobin, M., additional, Lindhorst, B., additional, Rost, S., additional, Smajić, S., additional, Straubmeier, C., additional, Tremou, E., additional, Wank, I., additional, and Zuther, J., additional
Published: 2012
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34. Glass fiber reinforced plastics within the fringe and flexure tracker of LINC-NIRVANA

Author: Smajic, Semir, primary, Eckart, A., additional, Horrobin, M., additional, Lindhorst, B., additional, Pott, J.-U., additional, Rauch, C., additional, Rost, S., additional, Straubmeier, C., additional, Tremou, E., additional, Wank, I., additional, and Zuther, J., additional
Published: 2012
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35. Beating the confusion limit: the necessity of high angular resolution for probing the physics of Sagittarius A* and its environment: opportunities for LINC-NIRVANA (LBT), GRAVITY (VLTI) and and METIS (E-ELT)

Author: Eckart, A., primary, Sabha, N., additional, Witzel, G., additional, Straubmeier, C., additional, Shahzamanian, B., additional, Valencia-S., M., additional, García-Marín, Macarena, additional, Horrobin, M., additional, Moser, L., additional, Zuther, J., additional, Fischer, S., additional, Rauch, C., additional, Rost, S., additional, Iserlohe, C., additional, Yazici, S., additional, Smajic, S., additional, Wiest, M., additional, Araujo-Hauck, C., additional, and Wank, I., additional
Published: 2012
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36. The GRAVITY spectrometers: system design

Author: Fischer, S., primary, Straubmeier, C., additional, Araujo-Hauck, C., additional, Yazici, S., additional, Wiest, M., additional, Wank, I., additional, Eisenhauer, F., additional, Perrin, G., additional, Eckart, A., additional, Perraut, K., additional, Brandner, W., additional, Amorim, A., additional, and Schöller, M., additional
Published: 2012
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37. The LINC-NIRVANA fringe and flexure tracker: first measurements of the testbed interferometer

Author: Moser, L., primary, Eckart, A., additional, Horrobin, M., additional, Lindhorst, B., additional, Rost, S., additional, Straubmeier, C., additional, Tremou, E., additional, Wank, I., additional, Zuther, J., additional, and Bertram, T., additional
Published: 2010
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38. Future Instrumentation to Observe the Galactic Center—Development of Astronomical Instrumentation at the University of Cologne

Author: Straubmeier, C., Araujo-Hauck, C., Eckart, A., Fischer, S., García-Marín, M., Horrobin, M., Lindhorst, B., Rost, S., Evangelia Tremou, Wank, I., Wiest, M., and Zuther, J.

39. Sub-milliarcsecond Optical Interferometry of the HMXB BP Cru with VLTI/GRAVITY

Author: Gravity, Collaboration, Waisberg, I., Dexter, J., Pfuhl, O., Abuter, R., Amorin, A., Anugu, N., Berger, J. P., Blind, N., Bonnet, H., Brandner, W., Buron, A., Clénet, Y., Wit, W., Deen, C., Delplancke-Ströbele, F., Dembet, R., Duvert, G., Eckart, A., Eisenhauer, F., Fédou, P., Finger, G., Garcia, P., Garcia Lopez, R., Gendron, E., Genzel, R., Gillessen, S., Haubois, X., Haug, M., Haussmann, F., Henning, Th, Hippler, S., Horrobin, M., Hubert, Z., Jochum, L., Jocou, L., Kervella, P., Kok, Y., Kulas, M., Lacour, S., Lapeyrère, V., Le Bouquin, J. -B, Lèna, P., Lippa, M., Mérand, A., Müller, E., Ott, T., Pallanca, L., Panduro, J., Paumard, T., Perraut, K., Perrin, G., Rabien, S., Ramírez, A., Ramos, J., Rau, C., Rohloff, R. -R, Rousset, G., Sanchez-Bermudez, J., Scheithauer, S., Schöller, M., Straubmeier, C., Sturm, E., Vincent, F., Wank, I., Wieprecht, E., Wiest, M., Wiezorrek, E., Wittkowski, M., Woillez, J., and Senol Yazici
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE), Astrophysics - Solar and Stellar Astrophysics, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics - High Energy Astrophysical Phenomena, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: 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 size of the hypergiant. Differential visibility amplitude ($\Delta |V| \sim 5\%$) and phase ($\Delta \phi \sim 2 \deg$) signatures are observed across the HeI $2.059 \mu$m and Br$\gamma$ lines, the latter seen strongly in emission, unusual for the donor star's spectral type. For a baseline $B \sim 100$m, the differential phase RMS $\sim 0.2 \deg$ corresponds to an astrometric precision of $\sim 2 \mu$as. A model-independent analysis in the marginally resolved limit of interferometry reveals asymmetric and extended emission with a strong wavelength dependence. We propose geometric models based on an extended and distorted wind and/or a high density gas stream, which has long been predicted to be present in this system. The observations show that optical interferometry is now able to resolve HMXBs at the spatial scale at which accretion takes place, and therefore probe the effects of the gravitational and radiation fields of the compact object on its environment., Comment: Submitted to ApJ, 22 pages, 17 figures

40. Neutral sphingomyelinase controls acute and chronic alcohol effects on brain activity.

Author: Wank I, Mittmann C, Kreitz S, Chestnykh D, Mühle C, Kornhuber J, Ludwig A, Kalinichenko LS, Müller CP, and Hess A
Subjects: Animals, Female, Mice, Alcohol Drinking, Central Nervous System Depressants pharmacology, Alcoholism, Sphingomyelin Phosphodiesterase metabolism, Sphingomyelin Phosphodiesterase genetics, Brain drug effects, Ethanol pharmacology, Ethanol administration & dosage, Mice, Knockout, Magnetic Resonance Imaging, Mice, Inbred C57BL
Abstract: Alcohol consumption is a widespread phenomenon throughout the world. However, how recreational alcohol use evolves into alcohol use disorder (AUD) remains poorly understood. The Smpd3 gene and its coded protein neutral sphingomyelinase (NSM) are associated with alcohol consumption in humans and alcohol-related behaviors in mice, suggesting a potential role in this transition. Using multiparametric magnetic resonance imaging, we characterized the role of NSM in acute and chronic effects of alcohol on brain anatomy and function in female mice. Chronic voluntary alcohol consumption (16 vol% for at least 6 days) affected brain anatomy in WT mice, reducing regional structure volume predominantly in cortical regions. Attenuated NSM activity prevented these anatomical changes. Functional MRI linked these anatomical adaptations to functional changes: Chronic alcohol consumption in mice significantly modulated resting state functional connectivity (RS FC) in response to an acute ethanol challenge (i.p. bolus of 2 g kg -1 ) in heterozygous NSM knockout (Fro), but not in WT mice. Acute ethanol administration in alcohol-naïve WT mice significantly decreased RS FC in cortical and brainstem regions, a key finding that was amplified in Fro mice. Regarding direct pharmacological effects, acute ethanol administration increased the regional cerebral blood volume (rCBV) in many brain areas. Here, chronic alcohol consumption otherwise attenuated the acute rCBV response in WT mice but enhanced it in Fro mice. Altogether, these findings suggest a differential role for NSM in acute and chronic functional brain responses to alcohol. Therefore, targeting NSM may be useful in the prevention or treatment of AUD., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)
Published: 2024
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41. The impact of HCN4 channels on CNS brain networks as a new target in pain development.

Author: Häfele M, Kreitz S, Ludwig A, Hess A, and Wank I
Abstract: While it is well established that the isoform 2 of the hyperpolarization-activated cyclic nucleotide-gated cation channel (HCN2) plays an important role in the development and maintenance of pain, the role of the closely related HCN4 isoform in the processing of nociceptive signals is not known. HCN4 channels are highly expressed in the thalamus, a region important for stimulus transmission and information processing. We used a brain-specific HCN4-knockout mouse line (HCN4-KO) to explore the role of HCN4 channels in acute nociceptive processing using several behavioral tests as well as a multimodal magnetic resonance imaging (MRI) approach. Functional MRI (fMRI) brain responses were measured during acute peripheral thermal stimulation complemented by resting state (RS) before and after stimulation. The data were analyzed by conventional and graph-theoretical approaches. Finally, high-resolution anatomical brain data were acquired. HCN4-KO animals showed a central thermal, but not a mechanical hypersensitivity in behavioral experiments. The open field analysis showed no significant differences in motor readouts between HCN4-KO and controls but uncovered increased anxiety in the HCN4-KO mice. Thermal stimulus-driven fMRI (s-fMRI) data revealed increased response volumes and response amplitudes for HCN4-KO, most pronounced at lower stimulation temperatures in the subcortical input, the amygdala as well as in limbic/hippocampal regions, and in the cerebellum. These findings could be cross-validated by graph-theoretical analyses. Assessment of short-term RS before and after thermal stimulation revealed that stimulation-related modulations of the functional connectivity only occurred in control animals. This was consistent with the finding that the hippocampus was found to be smaller in HCN4-KO. In summary, the deletion of HCN4 channels impacts on processing of acute nociception, which is remarkably manifested as a thermal hypersensitive phenotype. This was mediated by the key regions hypothalamus, somatosensory cortex, cerebellum and the amygdala. As consequence, HCN4-KO mice were more anxious, and their brain-wide RS functional connectivity could not be modulated by thermal nociceptive stimulation., Competing Interests: The author AH declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer EB declared a past co-authorship with the authors AH and IW to the handling editor., (Copyright © 2023 Häfele, Kreitz, Ludwig, Hess and Wank.)
Published: 2023
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42. Adult alcohol drinking and emotional tone are mediated by neutral sphingomyelinase during development in males.

Author: Kalinichenko LS, Mühle C, Jia T, Anderheiden F, Datz M, Eberle AL, Eulenburg V, Granzow J, Hofer M, Hohenschild J, Huber SE, Kämpf S, Kogias G, Lacatusu L, Lugmair C, Taku SM, Meixner D, Sembritzki NK, Praetner M, Rhein C, Sauer C, Scholz J, Ulrich F, Valenta F, Weigand E, Werner M, Tay N, Mc Veigh CJ, Haase J, Wang AL, Abdel-Hafiz L, Huston JP, Smaga I, Frankowska M, Filip M, Lourdusamy A, Kirchner P, Ekici AB, Marx LM, Suresh NP, Frischknecht R, Fejtova A, Saied EM, Arenz C, Bozec A, Wank I, Kreitz S, Hess A, Bäuerle T, Ledesma MD, Mitroi DN, Miranda AM, Oliveira TG, Lenz B, Schumann G, Kornhuber J, and Müller CP
Subjects: Male, Mice, Animals, Female, Alcohol Drinking, Anxiety metabolism, Brain metabolism, Ethanol, Sphingomyelin Phosphodiesterase genetics, Sphingomyelin Phosphodiesterase metabolism, Emotions
Abstract: Alcohol use, abuse, and addiction, and resulting health hazards are highly sex-dependent with unknown mechanisms. Previously, strong links between the SMPD3 gene and its coded protein neutral sphingomyelinase 2 (NSM) and alcohol abuse, emotional behavior, and bone defects were discovered and multiple mechanisms were identified for females. Here we report strong sex-dimorphisms for central, but not for peripheral mechanisms of NSM action in mouse models. Reduced NSM activity resulted in enhanced alcohol consumption in males, but delayed conditioned rewarding effects. It enhanced the acute dopamine response to alcohol, but decreased monoaminergic systems adaptations to chronic alcohol. Reduced NSM activity increased depression- and anxiety-like behavior, but was not involved in alcohol use for the self-management of the emotional state. Constitutively reduced NSM activity impaired structural development in the brain and enhanced lipidomic sensitivity to chronic alcohol. While the central effects were mostly opposite to NSM function in females, similar roles in bone-mediated osteocalcin release and its effects on alcohol drinking and emotional behavior were observed. These findings support the view that the NSM and multiple downstream mechanism may be a source of the sex-differences in alcohol use and emotional behavior., (© The Author(s) 2022. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
Published: 2023
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43. Influence of the Peripheral Nervous System on Murine Osteoporotic Fracture Healing and Fracture-Induced Hyperalgesia.

Author: Wank I, Niedermair T, Kronenberg D, Stange R, Brochhausen C, Hess A, and Grässel S
Subjects: Animals, Female, Mice, Bony Callus, Calcitonin Gene-Related Peptide, Fracture Healing physiology, Hyperalgesia etiology, Ovariectomy, Peripheral Nervous System, Chronic Pain, Osteoporotic Fractures diagnostic imaging
Abstract: Osteoporotic fractures are often linked to persisting chronic pain and poor healing outcomes. Substance P (SP), α-calcitonin gene-related peptide (α-CGRP) and sympathetic neurotransmitters are involved in bone remodeling after trauma and nociceptive processes, e.g., fracture-induced hyperalgesia. We aimed to link sensory and sympathetic signaling to fracture healing and fracture-induced hyperalgesia under osteoporotic conditions. Externally stabilized femoral fractures were set 28 days after OVX in wild type (WT), α-CGRP- deficient (α-CGRP -/-), SP-deficient (Tac1-/-) and sympathectomized (SYX) mice. Functional MRI (fMRI) was performed two days before and five and 21 days post fracture, followed by µCT and biomechanical tests. Sympathectomy affected structural bone properties in the fracture callus whereas loss of sensory neurotransmitters affected trabecular structures in contralateral, non-fractured bones. Biomechanical properties were mostly similar in all groups. Both nociceptive and resting-state (RS) fMRI revealed significant baseline differences in functional connectivity (FC) between WT and neurotransmitter-deficient mice. The fracture-induced hyperalgesia modulated central nociception and had robust impact on RS FC in all groups. The changes demonstrated in RS FC in fMRI might potentially be used as a bone traumata-induced biomarker regarding fracture healing under pathophysiological musculoskeletal conditions. The findings are of clinical importance and relevance as they advance our understanding of pain during osteoporotic fracture healing and provide a potential imaging biomarker for fracture-related hyperalgesia and its temporal development. Overall, this may help to reduce the development of chronic pain after fracture thereby improving the treatment of osteoporotic fractures.
Published: 2022
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44. Imaging the influence of peripheral TRPV1-signaling on cerebral nociceptive processing applying fMRI-based graph theory in a resiniferatoxin rat model.

Author: Wank I, Kutsche L, Kreitz S, Reeh P, and Hess A
Subjects: Animals, Male, Nociception physiology, Rats, TRPV Cation Channels agonists, Diterpenes pharmacology, Magnetic Resonance Imaging
Abstract: Resiniferatoxin (RTX), an extract from the spurge plant Euphorbia resinifera, is a potent agonist of the transient receptor potential cation channel subfamily V member 1 (TRPV1), mainly expressed on peripheral nociceptors-a prerequisite for nociceptive heat perception. Systemic overdosing of RTX can be used to desensitize specifically TRPV1-expressing neurons, and was therefore utilized here to selectively characterize the influence of TRPV1-signaling on central nervous system (CNS) temperature processing. Resting state and CNS temperature processing of male rats were assessed via functional magnetic resonance imaging before and after RTX injection. General linear model-based and graph-theoretical network analyses disentangled the underlying distinct CNS circuitries. At baseline, rats displayed an increase of nociception-related response amplitude and activated brain volume that correlated highly with increasing stimulation temperatures. In contrast, RTX-treated rats showed a clear disruption of thermal nociception, reflected in a missing increase of CNS responses to temperatures above 48°C. Graph-theoretical analyses revealed two distinct brain subnetworks affected by RTX: one subcortical (brainstem, lateral and medial thalamus, hippocampus, basal ganglia and amygdala), and one cortical (primary sensory, motor and association cortices). Resting state analysis revealed first, that peripheral desensitization of TRPV1-expressing neurons did not disrupt the basic resting-state-network of the brain. Second, only at baseline, but not after RTX, noxious stimulation modulated the RS-network in regions associated with memory formation (e.g. hippocampus). Altogether, the combination of whole-brain functional magnetic resonance imaging and RTX-mediated desensitization of TRPV1-signaling provided further detailed insight into cerebral processing of noxious temperatures., Competing Interests: AH reports grants from BMBF (NeuroImpa 01EC1403C and NeuroRad 02NUK034D) during the conduct of the study. Other than that, the authors have no financial conflict of interest to declare. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. This does not alter our adherence to PLOS ONE policies on sharing data and materials.
Published: 2022
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45. Neutral sphingomyelinase mediates the co-morbidity trias of alcohol abuse, major depression and bone defects.

Author: Kalinichenko LS, Mühle C, Jia T, Anderheiden F, Datz M, Eberle AL, Eulenburg V, Granzow J, Hofer M, Hohenschild J, Huber SE, Kämpf S, Kogias G, Lacatusu L, Lugmair C, Taku SM, Meixner D, Tesch N, Praetner M, Rhein C, Sauer C, Scholz J, Ulrich F, Valenta F, Weigand E, Werner M, Tay N, Mc Veigh CJ, Haase J, Wang AL, Abdel-Hafiz L, Huston JP, Smaga I, Frankowska M, Filip M, Lourdusamy A, Kirchner P, Ekici AB, Marx LM, Suresh NP, Frischknecht R, Fejtova A, Saied EM, Arenz C, Bozec A, Wank I, Kreitz S, Hess A, Bäuerle T, Ledesma MD, Mitroi DN, Miranda AM, Oliveira TG, Gulbins E, Lenz B, Schumann G, Kornhuber J, and Müller CP
Subjects: Animals, Comorbidity, Humans, Mice, Morbidity, Alcoholism genetics, Bone Diseases genetics, Depressive Disorder, Major genetics, Sphingomyelin Phosphodiesterase genetics
Abstract: Mental disorders are highly comorbid and occur together with physical diseases, which are often considered to arise from separate pathogenic pathways. We observed in alcohol-dependent patients increased serum activity of neutral sphingomyelinase. A genetic association analysis in 456,693 volunteers found associations of haplotypes of SMPD3 coding for NSM-2 (NSM) with alcohol consumption, but also with affective state, and bone mineralisation. Functional analysis in mice showed that NSM controls alcohol consumption, affective behaviour, and their interaction by regulating hippocampal volume, cortical connectivity, and monoaminergic responses. Furthermore, NSM controlled bone-brain communication by enhancing osteocalcin signalling, which can independently supress alcohol consumption and reduce depressive behaviour. Altogether, we identified a single gene source for multiple pathways originating in the brain and bone, which interlink disorders of a mental-physical co-morbidity trias of alcohol abuse-depression/anxiety-bone disorder. Targeting NSM and osteocalcin signalling may, thus, provide a new systems approach in the treatment of a mental-physical co-morbidity trias., (© 2021. The Author(s).)
Published: 2021
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46. Central amygdala circuitry modulates nociceptive processing through differential hierarchical interaction with affective network dynamics.

Author: Wank I, Pliota P, Badurek S, Kraitsy K, Kaczanowska J, Griessner J, Kreitz S, Hess A, and Haubensak W
Subjects: Amygdala cytology, Animals, Magnetic Resonance Imaging, Male, Mice, Mice, Inbred C57BL, Mice, Transgenic, Optogenetics methods, Protein Kinase C-delta metabolism, Protein Kinase C-delta physiology, Somatostatin metabolism, Somatostatin physiology, Affect physiology, Amygdala physiology, Nerve Net physiology, Nociception physiology
Abstract: The central amygdala (CE) emerges as a critical node for affective processing. However, how CE local circuitry interacts with brain wide affective states is yet uncharted. Using basic nociception as proxy, we find that gene expression suggests diverging roles of the two major CE neuronal populations, protein kinase C δ-expressing (PKCδ + ) and somatostatin-expressing (SST + ) cells. Optogenetic (o)fMRI demonstrates that PKCδ + /SST + circuits engage specific separable functional subnetworks to modulate global brain dynamics by a differential bottom-up vs. top-down hierarchical mesoscale mechanism. This diverging modulation impacts on nocifensive behavior and may underly CE control of affective processing.
Published: 2021
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47. The complement system drives local inflammatory tissue priming by metabolic reprogramming of synovial fibroblasts.

Author: Friščić J, Böttcher M, Reinwald C, Bruns H, Wirth B, Popp SJ, Walker KI, Ackermann JA, Chen X, Turner J, Zhu H, Seyler L, Euler M, Kirchner P, Krüger R, Ekici AB, Major T, Aust O, Weidner D, Fischer A, Andes FT, Stanojevic Z, Trajkovic V, Herrmann M, Korb-Pap A, Wank I, Hess A, Winter J, Wixler V, Distler J, Steiner G, Kiener HP, Frey B, Kling L, Raza K, Frey S, Kleyer A, Bäuerle T, Hughes TR, Grüneboom A, Steffen U, Krönke G, Croft AP, Filer A, Köhl J, Klein K, Buckley CD, Schett G, Mougiakakos D, and Hoffmann MH
Subjects: Adaptive Immunity immunology, Animals, Arthritis, Rheumatoid immunology, Cell Line, Dogs, Humans, Inflammation Mediators immunology, Madin Darby Canine Kidney Cells, Mice, Mice, Inbred BALB C, Mice, Inbred C57BL, Mice, Inbred NOD, Mice, SCID, Rats, Wistar, Signal Transduction immunology, Rats, Complement System Proteins immunology, Fibroblasts immunology, Inflammation immunology, Synovial Membrane immunology
Abstract: Arthritis typically involves recurrence and progressive worsening at specific predilection sites, but the checkpoints between remission and persistence remain unknown. Here, we defined the molecular and cellular mechanisms of this inflammation-mediated tissue priming. Re-exposure to inflammatory stimuli caused aggravated arthritis in rodent models. Tissue priming developed locally and independently of adaptive immunity. Repeatedly stimulated primed synovial fibroblasts (SFs) exhibited enhanced metabolic activity inducing functional changes with intensified migration, invasiveness and osteoclastogenesis. Meanwhile, human SF from patients with established arthritis displayed a similar primed phenotype. Transcriptomic and epigenomic analyses as well as genetic and pharmacological targeting demonstrated that inflammatory tissue priming relies on intracellular complement C3- and C3a receptor-activation and downstream mammalian target of rapamycin- and hypoxia-inducible factor 1α-mediated metabolic SF invigoration that prevents activation-induced senescence, enhances NLRP3 inflammasome activity, and in consequence sensitizes tissue for inflammation. Our study suggests possibilities for therapeutic intervention abrogating tissue priming without immunosuppression., Competing Interests: Declaration of interests A.F. received institutional research funding from Pfizer, Roche, UCB, Nascient, Mestag, and GSK. The other authors declare no competing interests., (Copyright © 2021 Elsevier Inc. All rights reserved.)
Published: 2021
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48. Common functional networks in the mouse brain revealed by multi-centre resting-state fMRI analysis.

Author: Grandjean J, Canella C, Anckaerts C, Ayrancı G, Bougacha S, Bienert T, Buehlmann D, Coletta L, Gallino D, Gass N, Garin CM, Nadkarni NA, Hübner NS, Karatas M, Komaki Y, Kreitz S, Mandino F, Mechling AE, Sato C, Sauer K, Shah D, Strobelt S, Takata N, Wank I, Wu T, Yahata N, Yeow LY, Yee Y, Aoki I, Chakravarty MM, Chang WT, Dhenain M, von Elverfeldt D, Harsan LA, Hess A, Jiang T, Keliris GA, Lerch JP, Meyer-Lindenberg A, Okano H, Rudin M, Sartorius A, Van der Linden A, Verhoye M, Weber-Fahr W, Wenderoth N, Zerbi V, and Gozzi A
Subjects: Animals, Brain diagnostic imaging, Connectome standards, Female, Image Processing, Computer-Assisted standards, Magnetic Resonance Imaging standards, Male, Mice, Mice, Inbred C57BL, Nerve Net diagnostic imaging, Reproducibility of Results, Brain physiology, Connectome methods, Image Processing, Computer-Assisted methods, Magnetic Resonance Imaging methods, Nerve Net physiology
Abstract: Preclinical applications of resting-state functional magnetic resonance imaging (rsfMRI) offer the possibility to non-invasively probe whole-brain network dynamics and to investigate the determinants of altered network signatures observed in human studies. Mouse rsfMRI has been increasingly adopted by numerous laboratories worldwide. Here we describe a multi-centre comparison of 17 mouse rsfMRI datasets via a common image processing and analysis pipeline. Despite prominent cross-laboratory differences in equipment and imaging procedures, we report the reproducible identification of several large-scale resting-state networks (RSN), including a mouse default-mode network, in the majority of datasets. A combination of factors was associated with enhanced reproducibility in functional connectivity parameter estimation, including animal handling procedures and equipment performance. RSN spatial specificity was enhanced in datasets acquired at higher field strength, with cryoprobes, in ventilated animals, and under medetomidine-isoflurane combination sedation. Our work describes a set of representative RSNs in the mouse brain and highlights key experimental parameters that can critically guide the design and analysis of future rodent rsfMRI investigations., (Copyright © 2019 Elsevier Inc. All rights reserved.)
Published: 2020
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49. Maternal immune activation during pregnancy impacts on brain structure and function in the adult offspring.

Author: Kreitz S, Zambon A, Ronovsky M, Budinsky L, Helbich TH, Sideromenos S, Ivan C, Konerth L, Wank I, Berger A, Pollak A, Hess A, and Pollak DD
Subjects: Animals, Brain diagnostic imaging, Disease Models, Animal, Female, Mice, Poly I-C immunology, Behavior, Animal, Mental Disorders etiology, Mental Disorders immunology, Pregnancy immunology, Prenatal Exposure Delayed Effects immunology, Prenatal Exposure Delayed Effects psychology
Abstract: Gestational infection constitutes a risk factor for the occurrence of psychiatric disorders in the offspring. Activation of the maternal immune system (MIA) with subsequent impact on the development of the fetal brain is considered to form the neurobiological basis for aberrant neural wiring and the psychiatric manifestations later in offspring life. The examination of validated animal models constitutes a premier resource for the investigation of the neural underpinnings. Here we used a mouse model of MIA based upon systemic treatment of pregnant mice with Poly(I:C) (polyriboinosinic-polyribocytidilic acid), for the unbiased and comprehensive analysis of the impact of MIA on adult offspring brain activity, morphometry, connectivity and function by a magnetic resonance imaging (MRI) approach. Overall lower neural activity, smaller brain regions and less effective fiber structure were observed for Poly(I:C) offspring compared to the control group. The corpus callosum was significantly smaller and presented with a disruption in myelin/ fiber structure in the MIA progeny. Subsequent resting-state functional MRI experiments demonstrated a paralleling dysfunctional interhemispheric connectivity. Additionally, while the overall flow of information was intact, cortico-limbic connectivity was hampered and limbic circuits revealed hyperconnectivity in Poly(I:C) offspring. Our study sheds new light on the impact of maternal infection during pregnancy on the offspring brain and identifies aberrant resting-state functional connectivity patterns as possible correlates of the behavioral phenotype with relevance for psychiatric disorders., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)
Published: 2020
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50. Contribution of Inflammation and Bone Destruction to Pain in Arthritis: A Study in Murine Glucose-6-Phosphate Isomerase-Induced Arthritis.

Author: Ebbinghaus M, Müller S, Segond von Banchet G, Eitner A, Wank I, Hess A, Hilger I, Kamradt T, and Schaible HG
Subjects: Activating Transcription Factor 3 metabolism, Animals, Arthritis, Experimental chemically induced, Arthritis, Experimental immunology, Arthritis, Rheumatoid chemically induced, Arthritis, Rheumatoid immunology, Bone Resorption immunology, Cyclic AMP Response Element-Binding Protein metabolism, Glucose-6-Phosphate Isomerase, Hindlimb physiopathology, Hyperalgesia immunology, Hyperalgesia physiopathology, Inflammation, Mice, T-Lymphocytes, Regulatory immunology, TRPV Cation Channels metabolism, Zoledronic Acid administration & dosage, Arthritis, Experimental physiopathology, Arthritis, Rheumatoid physiopathology, Bone Resorption physiopathology, Pain immunology
Abstract: Objective: Arthritis is often characterized by inflammation and bone destruction. This study was undertaken to investigate the contribution of inflammation and bone destruction to pain., Methods: Inflammation, bone resorption, pain-related behaviors, and molecular markers (activating transcription factor 3 [ATF-3], p-CREB, and transient receptor potential vanilloid channel 1) in sensory neurons were measured in murine glucose-6-phosphate isomerase (G6PI)-induced arthritis, a model of rheumatoid arthritis. Depletion of Treg cells before immunization changed self-limiting arthritis into nonremitting arthritis with pronounced bone destruction. Zoledronic acid (ZA) was administered to reduce bone resorption., Results: Compared to nondepleted mice, Treg cell-depleted mice exhibited arthritis with more severe bone destruction and higher guarding scores (P < 0.05; n = 10 mice per group) as well as more persistent thermal hyperalgesia (P < 0.05), but displayed similar mechanical hyperalgesia at the hindpaws (n = 18-26 mice per group). These pain-related behaviors, as well as an up-regulation of the neuronal injury marker ATF-3 in sensory neurons (studied in 39 mice), appeared before the clinical score (inflammation) became positive and persisted in Treg cell-depleted and nondepleted mice. In the late stage of arthritis, Treg cell-depleted mice treated with ZA showed less bone resorption (<50%; P < 0.01) and less thermal hyperalgesia (P < 0.01) than Treg cell-depleted mice without ZA treatment (n = 15 mice per group), but ZA treatment did not reduce the clinical score and local mechanical hyperalgesia., Conclusion: Pain-related behaviors precede and outlast self-limiting arthritis. In nonremitting arthritis with enhanced bone destruction, mainly local thermal, but not local mechanical, hyperalgesia was aggravated. The up-regulation of ATF-3 indicates an early and persisting affection of sensory neurons by G6PI-induced arthritis., (© 2019, American College of Rheumatology.)
Published: 2019
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