L. Burtscher

Leiden University

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R. Davies

Max Planck Institute for Extraterrestrial Physics

K. R. W. Tristram

European Southern Observatory

D. J. Rosario

Newcastle University

M. Schartmann

Max Planck Institute for Extraterrestrial Physics

R. van Boekel

Max Planck Institute for Astronomy

E. Sturm

Max Planck Institute for Extraterrestrial Physics

Jörg‐Uwe Pott

Max Planck Institute for Astronomy

G. Weigelt

Max Planck Institute for Radio Astronomy

D. Lutz

Max Planck Institute for Extraterrestrial Physics

G. Perrin

University of Pennsylvania

Cooperative Institutions

Centre National de la Recherche Scientifique

274

Max Planck Society

270

European Southern Observatory

189

Max Planck Institute for Astronomy

182

Max Planck Institute for Extraterrestrial Physics

175

European Southern Observatory

105

Université Paris Cité

104

Sorbonne Université

Observatoire de Paris

Laboratoire d’études spatiales et d’instrumentation en astrophysique

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THE PATH TO A MORE ACCESSIBLE AND INCLUSIVE FUTURE OF MEETINGS IN ASTRONOMY

Revista Mexicana de Astronomía y Astrofísica Serie de Conferencias (2022)

V. A. Moss Claire Trenham A. W. Hotan Rika Kobayashi G. A. Rees

The Future of Meetings (TFOM) began as a symposium dedicated to exploring the future of interaction in 2020, framed around key themes of accessibility, inclusivity, sustainability and technology, and with its roots in the astronomy community. Throughout our work in TFOM, it has been clear that the standard meeting practices taken for granted as a given in astronomy (and science) have long been inaccessible to many, creating a "normal" that is both exclusive and unsustainable. Conversely, the rapid advances in effective online means of communicating and collaborating open up a wealth of new possibilities for redefining what is required to succeed in astronomy, from the ground up. In this proceeding, we outline the lessons learned from and core recommendations of TFOM, specifically in the context of accessibility and inclusivity in astronomy. In the wake of pandemic disruption, we have a unique chance to rewrite the fabric of collaboration within our field. By doing so, we can establish new attraction and retention practices, maximising inclusivity while minimising environmental harm at a critical turning point for our long term survival as a species.

10.22201/ia.14052059p.2022.54.21

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VLTI/MIDI AGN Large Program observations (Burtscher+, 2013)

L. Burtscher K. Meisenheimer K. R. W. Tristram W. Jaffe S. F. Hönig

MIDI

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Warm calibration unit of the mid-infrared ELT instrument METIS: overview and current status towards FDR

Ground-based and Airborne Instrumentation for Astronomy IX (2022)

Monika Rutowska Tarun Kumar Sharma Michael Wiest Sabine Graf Lucas Labadie

The warm calibration unit (WCU) is one of the subsystems of the future METIS instrument on the Extremely Large Telescope (ELT). Operating at room temperature, the WCU is mounted above the main cryostat of METIS. It will be employed as a calibration reference for science observations, as well as for verification and alignment purposes during the AIT phase. The WCU is designed and constructed at the University of Cologne, one of the partner in the METIS consortium. WCU recently went through a successful Optics Long Lead Items Review by ESO. Now, the WCU is entering the last phase of the project, the Final Design Review (FDR). In this paper, we present the current status of the WCU design and summarize the mechanical and system engineering work. We describe the design of the hexapod formed by six manually adjustable links and its interfaces with the METIS cryostat together with the CFRP-based optical bench and Invar-based optical mounts. Lab prototyping results of one actuator under a nominal load of 5 kN confirms the achievable high linear resolution (20 µm). We present the status of the WCU laser cabinet. We discuss the lastest progress in the laboratory testing of some WCU functionalities, such as the fibre-fed monochromatic sources for the spectral calibration of the LM-Spectrograph of METIS, and the spatial calibration sources using the integrating sphere. We detail the activities foreseen until FDR together with the preparation of the sub-system MAIT work.

Metis

Cryostat

10.1117/12.2630802

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LLAMA: normal star formation efficiencies of molecular gas in the centres of luminous Seyfert galaxies

Monthly Notices of the Royal Astronomical Society (2017)

D. J. Rosario L. Burtscher R. Davies Michael Koss Cláudio Ricci

Using new APEX and JCMT spectroscopy of the CO 2-1 line, we undertake a controlled study of cold molecular gas in moderately luminous Active Galactic Nuclei (AGN) and inactive galaxies from the Luminous Local AGN with Matched Analogs (LLAMA) survey. We use spatially resolved infrared photometry of the LLAMA galaxies from 2MASS, WISE, IRAS & Herschel, corrected for nuclear emission using multi-component spectral energy distribution (SED) fits, to examine the dust-reprocessed star-formation rates (SFRs), molecular gas fractions and star formation efficiencies (SFEs) over their central 1 - 3 kpc. We find that the gas fractions and central SFEs of both active and inactive galaxies are similar when controlling for host stellar mass and morphology (Hubble type). The equivalent central molecular gas depletion times are consistent with the discs of normal spiral galaxies in the local Universe. Despite energetic arguments that the AGN in LLAMA should be capable of disrupting the observable cold molecular gas in their central environments, our results indicate that nuclear radiation only couples weakly with this phase. We find a mild preference for obscured AGN to contain higher amounts of central molecular gas, which suggests a connection between AGN obscuration and the gaseous environment of the nucleus. Systems with depressed SFEs are not found among the LLAMA AGN. We speculate that the processes that sustain the collapse of molecular gas into dense pre-stellar cores may also be a prerequisite for the inflow of material on to AGN accretion disks.

10.1093/mnras/stx2670

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Citations (67)

BROAD [C II] LINE WINGS AS TRACER OF MOLECULAR AND MULTI-PHASE OUTFLOWS IN INFRARED BRIGHT GALAXIES

The Astrophysical Journal (2016)

A. Janssen N. Christopher E. Sturm Sylvain Veilleux A. Contursi

ABSTRACT We report a tentative correlation between the outflow characteristics derived from OH absorption at 119 μ m and [C ii ] emission at 158 μ m in a sample of 22 local and bright ultraluminous infrared galaxies (ULIRGs). For this sample, we investigate whether [C ii ] broad wings are a good tracer of molecular outflows, and how the two tracers are connected. Fourteen objects in our sample have a broad wing component as traced by [C ii ], and all of these also show OH119 absorption indicative of an outflow (in one case an inflow). The other eight cases, where no broad [C ii ] component was found, are predominantly objects with no OH outflow or a low-velocity (≤100 km s −1 ) OH outflow. The FWHM of the broad [C ii ] component shows a trend with the OH119 blueshifted velocity, although with significant scatter. Moreover, and despite large uncertainties, the outflow masses derived from OH and broad [C ii ] show a 1:1 relation. The main conclusion is therefore that broad [C ii ] wings can be used to trace molecular outflows. This may be particularly relevant at high redshift, where the usual tracers of molecular gas (like low-J CO lines) become hard to observe. Additionally, observations of blueshifted Na i D λλ 5890, 5896 absorption are available for 10 of our sources. Outflow velocities of Na i D show a trend with OH velocity and broad [C ii ] FWHM. These observations suggest that the atomic and molecular gas phases of the outflow are connected.

Outflow

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TRACER

10.3847/0004-637x/822/1/43

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Sculpting the disk around TCha

HAL (Le Centre pour la Communication Scientifique Directe) (2013)

J. Olofsson M. Benisty J.-B. Le Bouquin Jean-Philippe Berger S. Lacour

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Thick turbulent gas disks with magnetocentrifugal winds in active galactic nuclei

Astronomy and Astrophysics (2018)

B. Vollmer M. Schartmann L. Burtscher Frédéric Marin S. F. Hönig

(Abridged) Infrared high-resolution imaging and interferometry have shown that the dust distribution is frequently elongated along the polar direction of an AGN. To explain these findings, we developed a model scenario for the inner ~30 pc of an AGN. We assume a rotating thick gas disk between about one and ten parsec. External gas accretion adds mass and injects energy via gas compression into this gas disk and drives turbulence. Our disks are assumed to be strongly magnetized via equipartition between the turbulent gas pressure and the energy density of the magnetic field. In a second step, we built three dimensional density cubes based on the analytical model, illuminated them with a central source, and made radiative transfer calculations. In a third step, we calculated MIR visibility amplitudes and compared them to available interferometric observations. We show that magnetocentrifugal winds starting from a thin and thick gas disk are viable in active galaxy centers. Once the wind is launched, it is responsible for the transport of angular momentum and the gas disk can become thin. The outflow scenario can account for the elongated dust structures, outer edges of the thin maser disks, and molecular outflows observed in local AGN. The models reproduce the observed terminal wind velocities, the scatter of the MIR/intrinsic X-ray correlation, and point source fractions. An application of the model to the Circinus Galaxy and NGC 1068 shows that the IR SED, available MIR interferometric observations, and optical polarization can be reproduced in a satisfactory way, provided that (i) a puff-up at the inner edge of the thin disk is present and (ii) a local screen with an optical depth of tau_V 20 in form of a local gas filament and/or a warp of the thick disk hide a significant fraction of both nuclei.

Outflow

Thin disk

Equipartition theorem

10.1051/0004-6361/201731133

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Citations (22)

Towards a physical understanding of the thermal background in large ground-based telescopes

L. Burtscher Ioannis Politopoulos Sergio Fernandez Acosta Tibor Agócs M. E. van den Ancker

Ground-based thermal-infrared observations have a unique scientific potential, but are also extremely challenging due to the need to accurately subtract the high thermal background. Since the established techniques of chopping and nodding need to be modified for observations with the future mid-infrared ELT imager and spectrograph (METIS), we investigate the sources of thermal background subtraction residuals. Our aim is to either remove or at least minimise the need for nodding in order to increase the observing efficiency for METIS. To this end we need to improve our knowledge about the origin of chop residuals and devise observing methods to remove them most efficiently, i.e. with the slowest possible nodding frequency. Thanks to dedicated observations with VLT/VISIR and GranTeCan/CanariCam, we have successfully traced the origin of three kinds of chopping residuals to (1) the entrance window, (2) the spiders and (3) other warm emitters in the pupil, in particular the VLT M3 mirror cell in its parking position. We conclude that, in order to keep chopping residuals stable over a long time (and therefore allow for slower nodding cycles), the pupil illumination needs to be kept constant, i.e. (imaging) observations should be performed in pupil-stabilised, rather than field-stabilised mode, with image de-rotation in the post-processing pipeline. This is now foreseen as the default observing concept for all METIS imaging modes.

Metis

10.1117/12.2576271

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Citations (2)

Obscuration in active galactic nuclei: near-infrared luminosity relations and dust colors

Astronomy and Astrophysics (2015)

L. Burtscher Gilles Orban de Xivry R. Davies A. Janssen D. Lutz

We combine two approaches to isolate the AGN luminosity at near-infrared wavelengths and relate the near-IR pure AGN luminosity to other tracers of the AGN. Using integral-field spectroscopic data of an archival sample of 51 local AGNs, we estimate the fraction of non-stellar light by comparing the nuclear equivalent width of the stellar 2.3 micron CO absorption feature with the intrinsic value for each galaxy. We compare this fraction to that derived from a spectral decomposition of the integrated light in the central arc second and find them to be consistent with each other. Using our estimates of the near-IR AGN light, we find a strong correlation with presumably isotropic AGN tracers. We show that a significant offset exists between type 1 and type 2 sources in the sense that type 1 sources are 7 (10) times brighter in the near-IR at log L_MIR = 42.5 (log L_X = 42.5). These offsets only becomes clear when treating infrared type 1 sources as type 1 AGNs. All AGNs have very red near-to-mid-IR dust colors. This, as well as the range of observed near-IR temperatures, can be explained with a simple model with only two free parameters: the obscuration to the hot dust and the ratio between the warm and hot dust areas. We find obscurations of A_V (hot) = 5 - 15 mag for infrared type 1 sources and A_V (hot) = 15 - 35 mag for type 2 sources. The ratio of hot dust to warm dust areas of about 1000 is nicely consistent with the ratio of radii of the respective regions as found by infrared interferometry.

10.1051/0004-6361/201525817

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A DEEPHERSCHEL/PACS OBSERVATION OF CO(40-39) IN NGC 1068: A SEARCH FOR THE MOLECULAR TORUS

The Astrophysical Journal (2015)

A. Janssen S. Bruderer E. Sturm A. Contursi R. Davies

Emission from high-J CO lines in galaxies has long been proposed as a tracer of X-ray dominated regions (XDRs) produced by AGN. Of particular interest is the question of whether the obscuring torus, which is required by AGN unification models, can be observed via high-J CO cooling lines. Here we report on the analysis of a deep Herschel-PACS observation of an extremely high J CO transition (40-39) in the Seyfert 2 galaxy NGC 1068. The line was not detected, with a derived 3$\sigma$ upper limit of $2 \times 10^{-17}\,\text{W}\,\text{m}^{-2}$. We apply an XDR model in order to investigate whether the upper limit constrains the properties of a molecular torus in NGC 1068. The XDR model predicts the CO Spectral Line Energy Distributions for various gas densities and illuminating X-ray fluxes. In our model, the CO(40-39) upper limit is matched by gas with densities $\sim 10^{6}-10^{7}\,\text{cm}^{-3}$, located at $1.6-5\,\text{pc}$ from the AGN, with column densities of at least $10^{25}\,\text{cm}^{-2}$. At such high column densities, however, dust absorbs most of the CO(40-39) line emission at $\lambda = 65.69\, \mu$m. Therefore, even if NGC 1068 has a molecular torus which radiates in the CO(40-39) line, the dust can attenuate the line emission to below the PACS detection limit. The upper limit is thus consistent with the existence of a molecular torus in NGC 1068. In general, we expect that the CO(40-39) is observable in only a few AGN nuclei (if at all), because of the required high gas column density, and absorption by dust.

Line (geometry)

10.1088/0004-637x/811/2/74

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Citations (2)