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1. Asgard/NOTT: L-band nulling interferometry at the VLTI

Author

Romain Laugier, Denis Defrère, Julien Woillez, Benjamin Courtney-Barrer, Felix A. Dannert, Alexis Matter, Colin Dandumont, Simon Gross, Olivier Absil, Azzurra Bigioli, Germain Garreau, Lucas Labadie, Jérôme Loicq, Marc-Antoine Martinod, Alexandra Mazzoli, Gert Raskin, and Ahmed Sanny

Subjects
interferometric, techniques: high angular resolution, methods: data analysis, methods: statistical [techniques], methods: statistical, techniques: interferometric, Space and Planetary Science, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM)
Abstract

Context. NOTT (formerly Hi-5) is a new high-contrast L′ band (3.5-4.0 μm) beam combiner for the VLTI designed with an ambitious aim to be sensitive to young giant exoplanets down to 5 mas separation around nearby stars. The performance of nulling interferometers in these wavelengths is affected both by fundamental noise from the background and contributions of instrumental noise. This motivates the development of end-to-end simulations to optimize these instruments. Aims. The aim of this study is to enable a performance evaluation of NOTT and inform the design of such instruments with current and future infrastructures in mind, taking into account the different sources of noise and their correlation. Methods. SCIFYsim is an end-to-end simulator for single-mode-filtered beam combiners, with an emphasis on nulling interferometers. We use it to compute a covariance matrix of the errors. We then use statistical detection tests based on likelihood ratios to compute compound detection limits for the instrument. Results. With the current assumptions as to the performance of the wavefront correction systems, the errors are dominated by correlated instrumental errors down to stars of magnitude 6-7 in the L band, beyond which thermal background from the telescopes and relay system becomes dominant. Conclusions. SCIFYsim is suited to anticipating some of the challenges of design, tuning, operation, and signal processing for integrated-optics beam combiners. The detection limits found for this early version of NOTT simulation with the unit telescopes are compatible with detections at contrasts up to 105 in the L band at separations of 5-80 mas around bright stars., Astronomy & Astrophysics, 671, ISSN:0004-6361, ISSN:1432-0746

Published
2023

2. Constraining particle acceleration in Sgr A⋆ with simultaneous GRAVITY, Spitzer, NuSTAR, and Chandra observations

Author

Wolfgang Brandner, A. Jiménez-Rosales, Mark Gurwell, Stefan Hippler, Christian Straubmeier, Th. Henning, Fiona A. Harrison, Jason Dexter, N. M. Förster Schreiber, F. Vincent, Pierre Kervella, Daryl Haggard, S. Yazici, Silvia Scheithauer, Oliver Pfuhl, Y. Dallilar, T. Taro Shimizu, Idel Waisberg, Odele Straub, K. Foster, Felix Widmann, Sera Markoff, Dieter Lutz, J.-B. Le Bouquin, M. Bauböck, Matthew Horrobin, Yann Clénet, P. T. de Zeeuw, Gabriele Ghisellini, Howard A. Smith, Frederick K. Baganoff, Daniel Stern, Thibaut Paumard, Eckhard Sturm, Ric Davies, M. Nowak, Andreas Eckart, Andreas Kaufer, Sebastian Rabien, Laurent Jocou, Paulo J. V. Garcia, Ekkehard Wieprecht, Reinhard Genzel, Jinyi Shangguan, G. Rodríguez-Coira, Patrick Lowrance, C. J. Hailey, Thomas Ott, S. Zhang, A. Drescher, G. Ponti, Giovanni G. Fazio, Steven P. Willner, S. D. von Fellenberg, Linda J. Tacconi, Maryam Habibi, H. Bonnet, Julien Woillez, V. Lapeyrère, Sylvestre Lacour, António Amorim, Erich Wiezorrek, Xavier Haubois, Guy Perrin, J. Neilsen, K. Mori, Eric Gendron, Frank Eisenhauer, G. Heißel, Pierre Léna, Joseph L. Hora, Karine Perraut, Charles F. Gammie, Feng Gao, G. Witzel, Gérard Zins, Mark Morris, André Young, Julia Stadler, Jean-Phillipe Berger, Hope Boyce, Stefan Gillessen, Lieselotte Jochum, Roberto Abuter, High Energy Astrophys. & Astropart. Phys (API, FNWI), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-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, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)

Subjects
Accretion, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Electron, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Astrophysics - high energy astrophysical phenomena, law.invention, Luminosity, symbols.namesake, law, 0103 physical sciences, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Accretion (meteorology), Galaxy: center, 010308 nuclear & particles physics, [SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Astronomy and Astrophysics, Black hole physics, Synchrotron, ddc, Particle acceleration, Lorentz factor, 13. Climate action, Space and Planetary Science, Accretion disks, symbols, Spectral energy distribution, Flare
Abstract

We report the time-resolved spectral analysis of a bright near-infrared and moderate X-ray flare of Sgr A*. We obtained light curves in the $M$-, $K$-, and $H$-bands in the mid- and near-infrared and in the $2-8~\mathrm{keV}$ and $2-70~\mathrm{keV}$ bands in the X-ray. The observed spectral slope in the near-infrared band is $\nu L_\nu\propto \nu^{0.5\pm0.2}$; the spectral slope observed in the X-ray band is $\nu L_\nu \propto \nu^{-0.7\pm0.5}$. We tested synchrotron and synchrotron self-Compton (SSC) scenarios. The observed near-infrared brightness and X-ray faintness, together with the observed spectral slopes, pose challenges for all models explored. We rule out a scenario in which the near-infrared emission is synchrotron emission and the X-ray emission is SSC. A one-zone model in which both the near-infrared and X-ray luminosity are produced by SSC and a model in which the luminosity stems from a cooled synchrotron spectrum can explain the flare. In order to describe the mean SED, both models require specific values of the maximum Lorentz factor $\gamma_{max}$, which however differ by roughly two orders of magnitude: the SSC model suggests that electrons are accelerated to $\gamma_{max}\sim 500$, while cooled synchrotron model requires acceleration up to $\gamma_{max}\sim5\times 10^{4}$. The SSC scenario requires electron densities of $10^{10}~\mathrm{cm^{-3}}$ much larger than typical ambient densities in the accretion flow, and thus require in an extraordinary accretion event. In contrast, assuming a source size of $1R_s$, the cooled synchrotron scenario can be realized with densities and magnetic fields comparable with the ambient accretion flow. For both models, the temporal evolution is regulated through the maximum acceleration factor $\gamma_{max}$, implying that sustained particle acceleration is required to explain at least a part of the temporal evolution of the flare., Comment: accepted for publication in Astronomy & Astrophysics; preview abstract shortened due to arXiv requirements

Published
2021

3. First MATISSE L-band observations of HD 179218

Author

Dieter Schertl, Th. Henning, Gerd Weigelt, Florentin Millour, József Varga, Stephane Lagarde, J. Hron, Walter Jaffe, J. Leftley, Karl-Heinz Hofmann, L. Klarmann, G. Yoffe, A. Soulain, M. Heininger, V. Hocdé, Marco Delbo, Felix C. M. Bettonvil, Paul Bristow, Anthony Meilland, Uwe Beckmann, F. Allouche, A. Bensberg, M. Lehmitz, J. C. Augereau, C. A. Hummel, Lucas Labadie, Gérard Zins, Philippe Berio, Uwe Graser, Farrokh Vakili, P. Antonelli, Markus Wittkowski, Pierre Cruzalèbes, Nathalie Ysard, C. Leinert, Carsten Dominik, L. B. F. M. Waters, Claudia Paladini, Isabelle Percheron, J. Duprat, Anthony P. Jones, Michiel R. Hogerheijde, E. Habart, Sylvie Robbe-Dubois, J. W. Isbell, Eric Pantin, R. van Boekel, Klaus Meisenheimer, Julien Woillez, Bruno Lopez, Alexis Matter, Péter Ábrahám, E. Kokoulina, Romain Petrov, V. Gámez Rosas, Emmanuel Dartois, Ph. Stee, Sebastian Wolf, J. Drevon, M. Dannhoff, William C. Danchi, Observatoire de la Côte d'Azur (OCA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Low Energy Astrophysics (API, FNWI), and Ysard, Nathalie

Subjects
Interferometric, 010504 meteorology & atmospheric sciences, Infrared, Astronomy, Continuum (design consultancy), chemistry.chemical_element, FOS: Physical sciences, Context (language use), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Spectral resolution, General, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Very Large Telescope, Protoplanetary Disks, Astronomy and Astrophysics, Techniques, Astrophysics - Solar and Stellar Astrophysics, Amorphous carbon, chemistry, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Circumstellar Matter, Spectral energy distribution, [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Astrophysics::Earth and Planetary Astrophysics, [SDU.ASTR.GA] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Astrophysics - Solar and Stellar Astrophysic, Carbon, Astrophysics - Earth and Planetary Astrophysics
Abstract

Context. Carbon is one of the most abundant components in the Universe. While silicates have been the main focus of solid phase studies in protoplanetary discs (PPDs), little is known about the solid carbon content especially in the planet-forming regions (~0.1–10 au). Fortunately, several refractory carbonaceous species present C-H bonds (such as hydrogenated nano-diamond and amorphous carbon as well as polycyclic aromatic hydrocarbons), which generate infrared (IR) features that can be used to trace the solid carbon reservoirs. The new mid-IR instrument MATISSE, installed at the Very Large Telescope Interferometer (VLTI), can spatially resolve the inner regions (~1–10 au) of PPDs and locate, down to the au-scale, the emission coming from carbon grains. Aims. Our aim is to provide a consistent view on the radial structure, down to the au-scale, as well as basic physical properties and the nature of the material responsible for the IR continuum emission in the inner disk region around HD 179218. Methods. We implemented a temperature-gradient model to interpret the disk IR continuum emission, based on a multiwavelength dataset comprising a broadband spectral energy distribution and VLTI H-, L-, and N-bands interferometric data obtained in low spectral resolution. Then, we added a ring-like component, representing the carbonaceous L-band features-emitting region, to assess its detectability in future higher spectral resolution observations employing mid-IR interferometry. Results. Our temperature-gradient model can consistently reproduce our dataset. We confirmed a spatially extended inner 10 au emission in H- and L-bands, with a homogeneously high temperature (~1700 K), which we associate with the presence of stochastically heated nano-grains. On the other hand, the N-band emitting region presents a ring-like geometry that starts at about 10 au with a temperature of 400 K. Moreover, the existing low resolution MATISSE data exclude the presence of aromatic carbon grains (i.e., producing the 3.3 μm feature) in close proximity tothe star (≲1 au). Future medium spectral resolution MATISSE data will confirm their presence at larger distances. Conclusions. Our best-fit model demonstrates the presence of two separated dust populations: nano-grains that dominate the near- to mid-IR emission in the inner 10 au region and larger grains that dominate the emission outward. The presence of such nano-grains in the highly irradiated inner 10 au region of HD 179218 requires a replenishment process. Considering the expected lifetime of carbon nano-grains from The Heterogeneous dust Evolution Model for Interstellar Solids (THEMIS model), the estimated disk accretion inflow of HD 179218 could significantly contribute to feed the inner 10 au region in nano-grains.Moreover, we also expect a local regeneration of those nano-grains by the photo-fragmentation of larger aggregates.

Published
2021

4. The GRAVITY young stellar object survey

Author

Paola Caselli, E. F. van Dishoeck, Feng Gao, Jaime E. Pineda, Karine Perraut, Lucas Labadie, Stefan Gillessen, Catherine Dougados, Felix Widmann, E. Sturm, Odele Straub, Eric Gendron, J.-B. Le Bouquin, Christian Straubmeier, L. Klarmann, Mercedes E. Filho, A. Eckart, Thomas Ott, J. Sanchez-Bermudez, Th. Henning, A. Drescher, V. Lapeyrère, Gérard Rousset, Zoltan Hubert, Matthew Horrobin, Paulo J. V. Garcia, Gilles Duvert, Julien Woillez, G. Heissel, Thibaut Paumard, Jean-Phillipe Berger, G. Rodríguez-Coira, R. Grellmann, Frederic H. Vincent, Laurent Jocou, J. Stadler, S. D. von Fellenberg, Sylvestre Lacour, António Amorim, Guy Perrin, Pierre Kervella, V. Coudé du Foresto, Frank Eisenhauer, R. Garcia Lopez, Reinhard Genzel, Dominique Segura-Cox, Pierre Léna, M. Bauböck, Myriam Benisty, T. Taro Shimizu, A. Caratti o Garatti, A. Jiménez-Rosales, Yann Clénet, P. T. de Zeeuw, Wolfgang Brandner, and Jinyi Shangguan

Subjects
Young stellar object, FOS: Physical sciences, Context (language use), Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Angular resolution, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Very Large Telescope, 010308 nuclear & particles physics, Astronomy and Astrophysics, Accretion (astrophysics), Vortex, Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

Protoplanetary disks drive some of the formation process (e.g., accretion, gas dissipation, formation of structures, etc.) of stars and planets. Understanding such physical processes is one of the main astrophysical questions. HD 163296 is an interesting young stellar object for which infrared and sub-millimeter observations have shown a prominent circumstellar disk with gaps plausibly created by forming planets. This study aims at characterizing the morphology of the inner disk in HD 163296 with multi-epoch near-infrared interferometric observations performed with GRAVITY at the Very Large Telescope Interferometer (VLTI). Our goal is to depict the K-band (lambda_0 ~ 2.2 um) structure of the inner rim with milliarcsecond (sub-au) angular resolution. Our data is complemented with archival PIONIER (H-band; lambda_0 ~ 1.65 um) data of the source. We performed a Gradient Descent parametric model fitting to recover the sub-au morphology of our source. Our analysis shows the existence of an asymmetry in the disk surrounding the central star of HD 163296. We confirm variability of the disk structure in the inner ~2 mas (0.2 au). While variability of the inner disk structure in this source has been suggested by previous interferometric studies, this is the first time that it is confirmed in the H- and K-bands by using a complete analysis of the closure phases and squared visibilities over several epochs. Because of the separation from the star, position changes, and persistence of this asymmetric structure on timescales of several years, we argue that it is a dusty feature (e.g., a vortex or dust clouds), probably, made by a mixing of sillicate and carbon dust and/or refractory grains, inhomogeneously distributed above the mid-plane of the disk., Accepted to be published in Astronomy and Astrophysics; main-body: 11 pages, 3 figures and 3 tables

Published
2021

5. Observations of the inner jet in NGC 1068 at 43 GHz

Author

W. Jaffe, Julien Woillez, W. D. Cotton, Guy Perrin, National Radio Astronomy Observatory, Charlottesville (NRAO), Leiden Observatory, 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, 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), Pôle Astronomie du LESIA, 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 Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and W. M. Keck Observatory

Subjects
Physics, Scattering, Linear polarization, Astrophysics::High Energy Astrophysical Phenomena, Astronomy, Astronomy and Astrophysics, Torus, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Plasma, Polarization (waves), Synchrotron, Galaxy, law.invention, Wavelength, [SDU]Sciences of the Universe [physics], Space and Planetary Science, law, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics
Abstract

International audience; We present the results of observations of the AGN in the Seyfret galaxy NGC 1068 at 43 GHz (7 mm wavelength) with 50 mas resolution. The results are consistent with the claim of Gallimore et al. (2004) that the nuclear component is dominated by thermal emission. This adds to the growing body of evidence that this component is dominated by a hot inner region of the obscuring torus rather than the base of the radio jet. However, possible detection of linear polarization from this component suggests some emission from the synchrotron emitting jet or that the polarization arises from Thompson scattering of the thermal emission by the nuclear plasma.

Published
2007

6. The resolved size and structure of hot dust in the immediate vicinity of AGN

Author

A. Jiménez-Rosales, Feng Gao, Reinhard Genzel, N. M. Förster Schreiber, T. Taro Shimizu, António Amorim, Julien Woillez, M. Bauböck, Sylvestre Lacour, Jason Dexter, Marc Schartmann, Christian Straubmeier, Wolfgang Brandner, R. L. Davies, Idel Waisberg, P. Vermot, Stefan Gillessen, Paulo J. V. Garcia, Mercedes Prieto, Konrad R. W. Tristram, K. Perraut, T. Paumard, Felix Widmann, Andreas Eckart, Jinyi Shangguan, Oliver Pfuhl, Linda J. Tacconi, Guy Perrin, Makoto Kishimoto, P. T. de Zeeuw, T. Ott, B. M. Peterson, Frank Eisenhauer, D. Rouan, P.-O. Petrucci, Sebastian F. Hönig, Eckhard Sturm, Damien Gratadour, Amiel Sternberg, F. Millour, Y. Clénet, Odele Straub, Dieter Lutz, Hagai Netzer, 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), Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), 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), GRAVITY, Max-Planck-Institut für Extraterrestrische Physik (MPE), Department of Earth Sciences [Oxford], University of Oxford [Oxford], Max Planck Institute for Extraterrestrial Physics (MPE), Max-Planck-Gesellschaft, Institute Patology and Imunology Molecular, Fac Ciencias, Universidade do Porto [Porto], Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Institut für Radioastronomie (MPIFR), 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), 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), Columbia University [New York], 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 of Physics - Riga, Latvian Academy of Sciences, Universität zu Köln, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Universidade do Porto, 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), COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Côte d'Azur (UCA)-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, 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), 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)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA), COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble [2020-....] (IPAG [2020-....]), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble [2020-....] (OSUG [2020-....]), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes [2020-....] (UGA [2020-....])-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes [2020-....] (UGA [2020-....])

Subjects
media_common.quotation_subject, Astrophysics::High Energy Astrophysical Phenomena, galaxies: active, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Asymmetry, law.invention, law, quasars: general, 0103 physical sciences, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, media_common, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), 010308 nuclear & particles physics, Bolometer, Astronomy and Astrophysics, Quasar, Astrophysics - Astrophysics of Galaxies, Galaxy, galaxies: Seyfert, Full width at half maximum, Interferometry, Space and Planetary Science, techniques: interferometric, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), Sublimation (phase transition), Astrophysics::Earth and Planetary Astrophysics, galaxies: nuclei, Astrophysics - High Energy Astrophysical Phenomena, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

We use VLTI/GRAVITY near-infrared interferometry measurements of 8 bright, Type 1 AGN to study the size and structure of hot dust heated by the central engine. We partially resolve each source, and report Gaussian FWHM sizes in the range 0.3-0.8 milliarcseconds. In all but one object, we find no evidence for significant elongation or asymmetry (closure phases < 1 deg). The effective physical radius increases with bolometric luminosity as found from past reverberation and interferometry measurements. The measured sizes for Seyfert galaxies are systematically larger than for the two quasars in our sample when measured relative to the previously reported R ~ L^1/2 relationship explained by emission at the sublimation radius. This could be evidence of evolving near-infrared emission region structure as a function of central luminosity., 13 pages, 9 figures, submitted to A&A

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