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1. Author's Reply to Comment by Greaves et al. on 'Phosphine in the Venusian Atmosphere: A Strict Upper Limit From SOFIA GREAT Observations'

Author

M. A. Cordiner, H. Wiesemeyer, G. L. Villanueva, I. dePater, J. Stutzki, G. Liuzzi, R. Aladro, S. B. Charnley, R. Cosentino, S. Faggi, V. Kofman, B. A. McGuire, S. N. Milam, A. Moullet, C. A. Nixon, and A. E. Thelen

Subjects
Venus, planetary atmospheres, sub‐mm spectroscopy, Geophysics. Cosmic physics, QC801-809
Abstract

Abstract In an attempt to understand the findings presented in the Comment by Greaves et al. (2023, https://doi.org/10.1029/2023GL103539), we followed their data analysis methodology, omitting the hot and cold‐load calibrations that are an important part of the standard SOFIA GREAT instrument calibration procedure. This process requires scaling of the Venus off‐source spectra by an arbitrary factor, which in turn introduces residuals of the intrinsic receiver bandpass shape as spurious components in the resulting line/continuum spectra. Although these additional artifacts can be reduced via Fourier‐domain spectral filtering, their removal depends on an ill‐constrained interpolation of the Venus continuum across the PH3 spectral line positions, resulting in an unreliable final spectrum. We therefore conclude that the PH3 lines claimed to be detected in the Comment by Greaves et al. (2023, https://doi.org/10.1029/2023GL103539) originate from data/analysis artifacts, and confirm our original result that there is no evidence for phosphine in the SOFIA Venus data.

Published
2023
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2. Phosphine in the Venusian Atmosphere: A Strict Upper Limit from SOFIA GREAT Observations

Author

M. A. Cordiner, G. L. Villanueva, H. Wiesemeyer, S. N. Milam, I. de Pater, A. Moullet, R. Aladro, C. A. Nixon, A. E. Thelen, S. B. Charnley, J. Stutzki, V. Kofman, S. Faggi, G. Liuzzi, R. Cosentino, and B. A. McGuire

Subjects
Astrophysics
Abstract

The presence of phosphine (PH3) in the atmosphere of Venus was reported by Greaves et al. based on observations of the J = 1–0 transition at 267 GHz using ground-based, millimeter-wave spectroscopy. This unexpected discovery presents a challenge for our understanding of Venus's atmosphere, and has led to a reappraisal of the possible sources and sinks of atmospheric phosphorous-bearing gases. Here we present results from a search for PH3 on Venus using the German REceiver for Astronomy at Terahertz Frequencies instrument aboard the Stratospheric Observatory for Infrared Astronomy aircraft, over three flights conducted in November 2021. Multiple PH3 transitions were targeted at frequencies centered on 533 and 1,067 GHz, but no evidence for atmospheric PH3 was detected. Through radiative transfer modeling, we derived a disk-averaged upper limit on the PH3 abundance of 0.8 ppb in the altitude range 75–110 km, which is more stringent than previous ground-based studies.

Published
2022
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3. NIKA 150 GHz polarization observations of the Crab nebula and its spectral energy distribution (Corrigendum)

Author

A. Ritacco, J. F. Macías-Pérez, N. Ponthieu, R. Adam, P. Ade, P. André, J. Aumont, A. Beelen, A. Benoît, A. Bideaud, N. Billot, O. Bourrion, A. Bracco, M. Calvo, A. Catalano, G. Coiffard, B. Comis, A. D’Addabbo, M. De Petris, F.-X. Désert, S. Doyle, J. Goupy, C. Kramer, G. Lagache, S. Leclercq, J.-F. Lestrade, P. Mauskopf, F. Mayet, A. Maury, A. Monfardini, F. Pajot, E. Pascale, L. Perotto, G. Pisano, M. Rebolo-Iglesias, V. Revéret, L. Rodriguez, C. Romero, H. Roussel, F. Ruppin, K. Schuster, A. Sievers, G. Siringo, C. Thum, S. Triqueneaux, C. Tucker, H. Wiesemeyer, R. Zylka, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), 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)-Météo-France -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)-Météo-France, Cardiff University, CEA- Saclay (CEA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -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)-Centre National d’Études Spatiales [Paris] (CNES), Hélium : du fondamental aux applications (NEEL - HELFA), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Instituto de RadioAstronomía Milimétrica (IRAM), Centre National de la Recherche Scientifique (CNRS), Cryogénie (NEEL - Cryo), Institut de RadioAstronomie Millimétrique (IRAM), Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome] (UNIROMA), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Joint ALMA Observatory (JAO), European Southern Observatory (ESO)-National Radio Astronomy Observatory (NRAO), and Max Planck Institute for Radio Astronomy

Subjects
polarization, supernovae: general, Space and Planetary Science, instrumentation: high angular resolution, instrumentation: detectors, [SDU]Sciences of the Universe [physics], Astronomy and Astrophysics, methods: observational, addenda, errata
Abstract

International audience

Published
2022
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4. SOFIA/GREAT observations of OD and OH rotational lines towards high-mass star forming regions

Author

T. Csengeri, F. Wyrowski, K. M. Menten, H. Wiesemeyer, R. Güsten, J. Stutzki, S. Heyminck, Y. Okada, and HEP, INSPIRE

Subjects
Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astronomy and Astrophysics, [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph], Astrophysics - Astrophysics of Galaxies, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

Only recently, OD, the deuterated isotopolog of hydroxyl, OH, has become accessible in the interstellar medium; spectral lines from both species have been observed in the supra-Terahertz and far infrared regime. Here we study rotational lines of OD and OH towards 13 Galactic high-mass star forming regions, with the aim to constrain the OD abundance and infer the deuterium fractionation of OH in their molecular envelopes. We used the Stratospheric Observatory for Infrared Astronomy (SOFIA) to observe the $^2\Pi_{3/2}$ $J=5/2-3/2$ ground-state transition of OD at 1.3 THz ($215~\mu$m) and the rotationally excited OH line at 1.84 THz ($163~\mu$m). We also used published high-spectral-resolution SOFIA data of the OH ground-state transition at 2.51 THz ($119.3~\mu$m). Our results show that absorption from the $^2\Pi_{3/2}$ OD $J=5/2-3/2$ ground-state transition is prevalent in the dense clumps surrounding active sites of high-mass star formation. We performed detailed radiative transfer modelling to investigate the OD abundance profile in the inner envelope for a large fraction of our sample. Our modelling suggests that part of the absorption arises from the denser inner parts, while the bulk of it as seen with SOFIA originates in the outer, cold layers of the envelope for which our constraints on the molecular abundance suggest a strong enhancement in deuterium fractionation. We find a weak negative correlation between the OD abundance and the bolometric luminosity to mass ratio, an evolutionary indicator, suggesting a slow decrease of OD abundance with time. A comparison with HDO shows a similarly high deuterium fractionation for the two species in the cold envelopes, which is of the order of 0.48% for the best studied source, G34.26+0.15. Our results are consistent with chemical models that favour rapid exchange reactions to form OD in the dense cold gas., Comment: 20 pages, 14 figures. Accepted by A&A after refereeing and language corrections. Abstract abbreviated

Published
2022
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5. HyGAL: Characterizing the Galactic Interstellar Medium with Observations of Hydrides and Other Small Molecules. I. Survey Description and a First Look Toward W3(OH), W3 IRS5, and NGC 7538 IRS1

Author

A. M. Jacob, D. A. Neufeld, P. Schilke, H. Wiesemeyer, W.-J. Kim, S. Bialy, M. Busch, D. Elia, E. Falgarone, M. Gerin, B. Godard, R. Higgins, P. Hennebelle, N. Indriolo, D. C. Lis, K. M. Menten, A. Sanchez-Monge, T. Möller, V. Ossenkopf-Okada, M. R. Rugel, D. Seifried, P. Sonnentrucker, S. Walch, M. G. Wolfire, F. Wyrowski, and V. Valdivia

Subjects
Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract

The HyGAL SOFIA legacy program surveys six hydride molecules -- ArH+, OH+, H2O+, SH, OH, and CH -- and two atomic constituents -- C+ and O -- within the diffuse interstellar medium (ISM) by means of absorption-line spectroscopy toward 25 bright Galactic background continuum sources. This detailed spectroscopic study is designed to exploit the unique value of specific hydrides as tracers and probes of different phases of the ISM, as demonstrated by recent studies with the Herschel Space Observatory. The observations performed under the HyGAL program will allow us to address several questions related to the lifecycle of molecular material in the ISM and the physical processes that impact its phase transition, such as: (1) What is the distribution function of the H2 fraction in the ISM? (2) How does the ionization rate due to low-energy cosmic-rays vary within the Galaxy? (3) What is the nature of interstellar turbulence, and what mechanisms lead to its dissipation? This overview discusses the observing strategy, synergies with ancillary and archival observations, the data reduction and analysis schemes adopted; and presents the first results obtained toward three of the survey targets, W3(OH), W3IRS5 and NGC7538IRS1. Robust measurements of the column densities of these hydrides -- obtained through widespread observations of absorption lines-- help address the questions raised, and there is a timely synergy between these observations and the development of theoretical models, particularly pertaining to the formation of H2 within the turbulent ISM. The provision of enhanced HyGAL data products will therefore serve as a legacy for future ISM studies., 33 pages, 17 figures, 7 tables. Accepted for publication in the Astrophysical Journal

Published
2022
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7. Polarization of the Recombination Line Maser in MWC349

Author

C. Thum, D. Morris, and H. Wiesemeyer

Subjects
Physics, Zeeman effect, Astronomy and Astrophysics, Astrophysics, Polarization (waves), Spectral line, Magnetic field, law.invention, symbols.namesake, T Tauri star, Space and Planetary Science, law, symbols, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Maser, Astrophysics::Galaxy Astrophysics, Circular polarization, Dynamo
Abstract

We present observations of the circular polarization of the recombination line maser in MWC 349. Six good quality Ha30α spectra were obtained during 2010 – 2011 which show that the Zeeman features are complex, time variable, and usually different for the blue- and red-shifted maser spikes. We propose that the magnetic field, located in the corona of the circumstellar disk, has toroidal and radial components. It is plausibly generated in a disk dynamo.

Published
2012
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8. A 3.5 mm POLARIMETRIC SURVEY OF RADIO-LOUD ACTIVE GALACTIC NUCLEI

Author

Iván Agudo, H. Wiesemeyer, Thomas P. Krichbaum, and C. Thum

Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO), Active galactic nucleus, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, symbols.namesake, 0103 physical sciences, Stokes parameters, Blazar, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Circular polarization, High Energy Astrophysical Phenomena (astro-ph.HE), Physics, 010308 nuclear & particles physics, Linear polarization, Astronomy and Astrophysics, Quasar, Position angle, 13. Climate action, Space and Planetary Science, symbols, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics, Fermi Gamma-ray Space Telescope
Abstract

We present the results from the first large (>100 source) 3.5 mm polarimetric survey of radio loud active galactic nuclei (AGN). The I, Q, U, and V Stokes parameter observations were performed with the XPOL polarimeter at the IRAM 30m Telescope. Our sample consists of 145 flat-radio-spectrum AGN with declination >-30 deg. (J2000.0) and flux density >~1Jy at 86GHz, as measured at the IRAM 30 m Telescope from 1978 to 1994. We detected linear and circular polarization (above 3 sigma levels of ~1.6%, and ~0.3%) for 76%, and 6% of the sample, respectively. We find a clear excess in degree of linear polarization detected at 86 GHz with regard to that at 15 GHz by a factor of ~2. Over our entire source sample, the luminosity of the jets is inversely proportional to the degree of linear polarization. Consistent with previous findings claiming larger Doppler factors for brighter gamma-ray blazars, quasars listed in our sample, and in the Fermi-LBAS catalog, show larger luminosities than non-LBAS ones, but our data do not allow us to confirm the same for BL Lac objects. We do not find a clear relation between the linear polarization angle and the jet structural position angle for any source class in our sample. We interpret this as the consequence of a markedly non-axisymmetric character of the 3 mm emitting region in the jets. We find that intrinsic circular polarization is the most likely mechanism for generation of the circular polarization detected in our observations. Our new data can be used to estimate the 3 mm AGN contribution to measurements of the linear polarization of the cosmic microwave background, such as those performed by the Planck satellite., Published in the Astrophysical Journal Supplement Series. 25 pages, 2 tables & 13 figures

Published
2010
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9. 3mm POLARIZATION PROPERTIES OF OPTICAL AND γ-RAY CLASSES OF BLAZARS

Author

Thomas P. Krichbaum, H. Wiesemeyer, C. Thum, and Iván Agudo

Subjects
Physics, Active galactic nucleus, Linear polarization, Astrophysics::High Energy Astrophysical Phenomena, Astronomy, Astronomy and Astrophysics, Quasar, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Position angle, Polarization (waves), law.invention, Telescope, symbols.namesake, Space and Planetary Science, law, Faraday effect, symbols, Blazar, Astrophysics::Galaxy Astrophysics, Mathematical Physics
Abstract

We have performed the first 3.5 mm polarimetric survey of radio loud active galactic nuclei (AGN) with the IRAM 30 m Telescope. Unlike radio wavelengths, millimeter observations allow us to measure the intrinsic linearly polarized emission from AGN, thanks to the marginal effect of Faraday rotation and depolarization at mm wavelengths. The sample contains 145 sources, and it essentially consists of all flat-spectrum AGN with declinations accessible to the 30 m Telescope (Dec. ( J 2000.0) > -30°), and with 3 mm flux density ≳ 1 Jy, as measured from 1978 to 1994. LBAS quasars in our sample show larger luminosity than non-LBAS ones, which is consistent with previous work claiming larger Doppler factors for brighter γ-ray blazars. This effect cannot be claimed for BL Lacertae objects in our sample, which suggests that only quasars contribute to distribute LBAS blazars towards larger luminosities. We find a systematic 3.5 mm linear polarization degree excess by a factor of ~ 2 with regard to the one at 2 cm for all optical and γ-ray classes of sources considered here. Our sample shows a significant trend to increase the luminosity of their jets for decreasing linear polarization fraction. Unlike previous studies in the radio spectral range, we do not find a clear relation between the linear polarization angle and the jet structural position angle of any source class in our sample. This is interpreted as a markedly non-axisymmetric character of the 3 mm emitting region of radio loud AGN jets.

Published
2010
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10. Excitation conditions and energetics of the dense gas in M17 SW

Author

M. Spaans, Karl M. Menten, M. A. Requena-Torres, Volker Ossenkopf, Rolf Güsten, J. P. Pérez-Beaupuits, H. Wiesemeyer, C. Guevara, J. Stutzki, and Astronomy

Subjects
Physics, General Engineering, Spectral density, Astronomy and Astrophysics, law.invention, Telescope, Atmospheric radiative transfer codes, Space and Planetary Science, law, Radiative transfer, Molecule, Isotopologue, Atomic physics, Excitation, Line (formation)
Abstract

The chemical and energetic conditions created by radiative feedback are probed with observations of multiple molecular transitions toward M17 SW. Extensive maps, including the 12 CO J = 16 → 15, J = 12 → 11, and J = 11 → 10 lines, as well as the HCN J = 8 → 7 and HCO + J = 9 → 8 transitions, were obtained with the dual band receiver GREAT on board the SOFIA airborne telescope, and with the ground based APEX and IRAM 30 m telescopes. These data provide extensive line spectral energy distributions (LSEDs) of the CO, HCN and HCO + molecules (and their isotopologues). The excitation conditions of the three species are estimated simultaneously using the same density and temperature in a two-phase non-LTE radiative transfer model of the LSEDs.

Published
2016

11. The molecular emission from old supernova remnants

Author

H. Wiesemeyer, S. Anderl, Antoine Gusdorf, R. Güsten, and T. Hezareh

Subjects
Physics, Shock wave, education.field_of_study, Star formation, Astrophysics::High Energy Astrophysical Phenomena, Population, FOS: Physical sciences, Astronomy and Astrophysics, Cosmic ray, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Momentum, Interstellar medium, Supernova, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), education, Astrophysics::Galaxy Astrophysics
Abstract

Supernovae constitute a critical source of energy input to the interstellar medium (ISM). In this short review, we focus on their latest phase of evolution, the supernova remnants (SNRs). We present observations of three old SNRs that have reached the phase where they interact with the ambient ISM: W28, IC443, and 3C391. We show that such objects make up clean laboratories to constrain the physical and chemical processes at work in molecular shock environments. Our studies subsequently allow us to quantify the impact of SNRs on their environment in terms of mass, momentum, and energy dissipation. In turn, their contribution to the energy balance of galaxies can be assessed. Their potential to trigger a further generation of star formation can also be investigated. Finally, our studies provide strong support for the interpretation of gamma-ray emission in SNRs, a crucial step to answer questions related to cosmic rays population and acceleration., 4 pages, 3 figures, to appear in Supernova environmental impacts, Proceedings IAU Symposium No. 296, 2013, A. Ray & D. McCray, eds

Published
2014

12. The high activity of 3C 454.3 in autumn 2007. Monitoring by the WEBT during the AGILE detection

Author

C. M. Raiteri, M. Villata, W. P. Chen, W.-S. Hsiao, O. M. Kurtanidze, K. Nilsson, V. M. Larionov, M. A. Gurwell, I. Agudo, H. D. Aller, M. F. Aller, E. Angelakis, A. A. Arkharov, U. Bach, M. Böttcher, C. S. Buemi, P. Calcidese, P. Charlot, F. D'Ammando, I. Donnarumma, E. Forné, A. Frasca, L. Fuhrmann, J. L. Gómez, V. A. Hagen-Thorn, S. G. Jorstad, G. N. Kimeridze, T. P. Krichbaum, A. Lähteenmäki, L. Lanteri, G. Latev, J.-F. Le Campion, C.-U. Lee, P. Leto, H.-C. Lin, N. Marchili, E. Marilli, A. P. Marscher, R. Nesci, E. Nieppola, M. G. Nikolashvili, J. Ohlert, E. Ovcharov, D. Principe, T. Pursimo, B. Ragozzine, A. C. Sadun, L. A. Sigua, R. L. Smart, A. Strigachev, L. O. Takalo, M. Tavani, C. Thum, M. Tornikoski, C. Trigilio, K. Uckert, G. Umana, A. Valcheva, S. Vercellone, A. Volvach, H. Wiesemeyer, INAF - Osservatorio Astrofisico di Torino (OATo), Istituto Nazionale di Astrofisica (INAF), Laboratoire de Physico-Chimie de l'Atmosphère (LPCA), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale, Laboratoire de chimie bactérienne (LCB), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Fujian Institute of Research on the Structure of Matter, National Engineering Research Center for Optoelectronic Crystalline Materials, Chinese Academy of Sciences, Insitute of Geology China Earthquake Administration Beijing 100029, China (X.X., G.C., W.C.) (INSITUTE OF GEOLOGY), Insitute of Geology, ECE Dept., University of Wisconsin-Madison, Harbin Institute of Technology (HIT), Department of Information Science and Media Studies [Bergen], University of Bergen (UIB), Institute of Geology, Chinese Academy of Sciences [Changchun Branch] (CAS), Linköping University (LIU), Department of Mechanical Engineering, National Chung-Hsing University, Research Center for Environmental Changes, Institute of Earthquake Prediction Research, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université du Littoral Côte d'Opale (ULCO)-Centre National de la Recherche Scientifique (CNRS), Department of Information Science and Media Studies [Bergen] (UiB), University of Bergen (UiB), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Raiteri CM, Villata M, Chen WP, Hsiao WS, Kurtanidze OM, Nilsson K, Larionov VM, Gurwell MA, Agudo I, Aller HD, Aller MF, Angelakis E, Arkharov AA, Bach U, Bottcher M, Buemi CS, Calcidese P, Charlot P, DAmmando F, Donnarumma I, Forne E, Frasca A, Fuhrmann L, Gomez JL, Hagen-Thorn VA, Jorstad SG, Kimeridze GN, Krichbaum TP, Lahteenmaki A, Lanteri L, Latev G, Le Campion JF, Lee CU, Leto P, Lin HC, Marchili N, Marilli E, Marscher AP, Nesci R, Nieppola E, Nikolashvili MG, Ohlert J, Ovcharov E, Principe D, Pursimo T, Ragozzine B, Sadun AC, Sigua LA, Smart RL, Strigachev A, Takalo LO, Tavani M, Thum C, Tornikoski M, Trigilio C, Uckert K, Umana G, Valcheva A, Vercellone S, Volvach A, and Wiesemeyer H

Subjects
Brightness, Swift Gamma-Ray Burst Mission, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Extinction (astronomy), galaxies: active, FOS: Physical sciences, Flux, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, galaxies: active -- galaxies: quasars: general -- galaxies: quasars: individual: 3C 454.3, 01 natural sciences, law.invention, Telescope, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], law, 0103 physical sciences, galaxies: quasars: individual: 3C 454.3, Blazar, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astrophysics (astro-ph), Astronomy and Astrophysics, Light curve, galaxies: quasars: general, Space and Planetary Science, Satellite
Abstract

The quasar-type blazar 3C 454.3 underwent a phase of high activity in summer and autumn 2007, which was intensively monitored in the radio-to-optical bands by the Whole Earth Blazar Telescope (WEBT). The gamma-ray satellite AGILE detected this source first in late July, and then in November-December 2007. In this letter we present the multifrequency data collected by the WEBT and collaborators during the second AGILE observing period, complemented by a few contemporaneous data from UVOT onboard the Swift satellite. The aim is to trace in detail the behaviour of the synchrotron emission from the blazar jet, and to investigate the contribution from the thermal emission component. Optical data from about twenty telescopes have been homogeneously calibrated and carefully assembled to construct an R-band light curve containing about 1340 data points in 42 days. This extremely well-sampled optical light curve allows us to follow the dramatic flux variability of the source in detail. In addition, we show radio-to-UV spectral energy distributions (SEDs) at different epochs, which represent different brightness levels. In the considered period, the source varied by 2.6 mag in a couple of weeks in the R band. Many episodes of fast (i.e. intranight) variability were observed, most notably on December 12, when a flux increase of about 1.1 mag in 1.5 hours was detected, followed by a steep decrease of about 1.2 mag in 1 hour. The contribution by the thermal component is difficult to assess, due to the uncertainties in the Galactic, and possibly also intrinsic, extinction in the UV band. However, polynomial fitting of radio-to-UV SEDs reveals an increasing spectral bending going towards fainter states, suggesting a UV excess likely due to the thermal emission from the accretion disc., 5 pages, 4 figures, accepted for publication in Astronomy & Astrophysics Letters

Published
2008
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13. Numerical methods for non-LTE line radiative transfer: Performance and convergence characteristics

Author

G. J. van Zadelhoff, Mika Juvela, Michiel R. Hogerheijde, Volker Ossenkopf, H. Wiesemeyer, Steven D. Doty, Cornelis P. Dullemond, F. L. Schoeier, F. F. S. van der Tak, and Jeremy Yates

Subjects
Physics, education.field_of_study, Astrophysics (astro-ph), Population, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Radius, Power law, Computational physics, Space and Planetary Science, Optical depth (astrophysics), Calibration, Radiative transfer, education, Envelope (waves), Line (formation)
Abstract

Comparison is made between a number of independent computer programs for radiative transfer in molecular rotational lines. The test models are spherically symmetric circumstellar envelopes with a given density and temperature profile. The first two test models have a simple power law density distribution, constant temperature and a fictive 2-level molecule, while the other two test models consist of an inside-out collapsing envelope observed in rotational transitions of HCO+. For the 2-level molecule test problems all codes agree well to within 0.2%, comparable to the accuracy of the individual codes, for low optical depth and up to 2% for high optical depths (tau=4800). The problem of the collapsing cloud in HCO+ has a larger spread in results, ranging up to 12% for the J=4 population. The spread is largest at the radius where the transition from collisional to radiative excitation occurs. The resulting line profiles for the HCO+ J=4-3 transition agree to within 10%, i.e., within the calibration accuracy of most current telescopes. The comparison project and the results described in this paper provide a benchmark for future code development, and give an indication of the typical accuracy of present day calculations of molecular line transfer., Comment: Accepted for publication in A&A

Published
2002

14. Planck early results. VI. The High Frequency Instrument data processing

Author

Hfi Core Team, P, Ade, P, Aghanim, N, Ansari, R, Arnaud, M, Ashdown, M, Aumont, J, Banday, A, Bartelmann, M, Bartlett, J, Battaner, E, Benabed, K, Benoit, A, Bernard, J, Bersanelli, M, Bock, J, Bond, J, Borrill, J, Bouchet, F, Boulanger, F, Bradshaw, T, Bucher, M, Cardoso, J, Castex, G, Catalano, A, Challinor, A, Chamballu, A, Chary, R, Chen, X, Chiang, C, Church, S, Clements, D, Colley, J, Colombi, S, Couchot, F, Coulais, A, Cressiot, C, Crill, B, Crook, M, De Bernardis, P, Delabrouille, J, Delouis, J, Desert, F, Dolag, K, Dole, H, Dore, O, Douspis, M, Dunkley, J, Efstathiou, G, Filliard, C, Forni, O, Fosalba, P, Ganga, K, Giard, M, Girard, D, Giraud-Heraud, Y, Gispert, R, Gorski, K, Gratton, S, Griffin, M, Guyot, G, Haissinski, J, Harrison, D, Helou, G, Henrot-Versille, S, Hernandez-Monteagudo, C, Hildebrandt, S, Hills, R, Hivon, E, Hobson, M, Holmes, W, Huffenberger, K, Jaffe, A, Jones, W, Kaplan, J, Kneissl, R, Knox, L, Kunz, M, Lagache, G, Lamarre, J, Lange, A, Lasenby, A, Lavabre, A, Lawrence, C, Le Jeune, M, Leroy, C, Lesgourgues, J, Macias-Perez, J, Mactavish, C, Maffei, B, Mandolesi, N, Mann, R, Marleau, F, Marshall, D, Masi, S, Matsumura, T, Mcauley, I, Mcgehee, P, Melin, J, Mercier, C, Mitra, S, Miville-Deschenes, M, Moneti, A, Montier, L, Mortlock, D, Murphy, A, Nati, F, Netterfield, C, Nørgaard-Nielsen, H, Norgaard-Nielsen, H, North, C, Noviello, F, Novikov, D, Osborne, S, Pajot, F, Patanchon, G, Peacocke, T, Pearson, T, Perdereau, O, Perotto, L, Piacentini, F, Piat, M, Plaszczynski, S, Pointecouteau, E, Ponthieu, N, Prezeau, G, Prunet, S, Puget, J, Reach, W, Remazeilles, M, Renault, C, Riazuelo, A, Ristorcelli, I, Rocha, G, Rosset, C, Roudier, G, Rowan-Robinson, M, Rusholme, B, Saha, R, Santos, D, Savini, G, Schaefer, B, Shellard, P, Spencer, L, Starck, J, Stolyarov, V, Stompor, R, Sudiwala, R, Sunyaev, R, Sutton, D, Sygnet, J, Tauber, J, Thum, C, Torre, J, Touze, F, Tristram, M, Van Leeuwen, F, Vibert, L, Vibert, D, Wade, L, Wandelt, B, White, S, Wiesemeyer, H, Woodcraft, A, Yurchenko, V, Yvon, D, Zacchei, A, Planck Hfi Core Team, P.A.R. Ade, N. Aghanim, R. Ansari, M. Arnaud, M. Ashdown, J. Aumont, A.J. Banday, M. Bartelmann, J.G. Bartlett, E. Battaner, K. Benabed, A. Benoit, J.P. Bernard, M. Bersanelli, J.J. Bock, J.R. Bond, J. Borrill, F.R. Bouchet, F. Boulanger, T. Bradshaw, M. Bucher, J.F. Cardoso, G. Castex, A. Catalano, A. Challinor, A. Chamballu, R.R. Chary, X. Chen, C. Chiang, S. Church, D.L. Clements, J.M. Colley, S. Colombi, F. Couchot, A. Coulais, C. Cressiot, B.P. Crill, M. Crook, Paolo De Bernardis, J. Delabrouille, J.M. Delouis, F.X. Desert, K. Dolag, H. Dole, O. Dore, M. Douspis, J. Dunkley, G. Efstathiou, C. Filliard, O. Forni, P. Fosalba, K. Ganga, M. Giard, D. Girard, Y. Giraud-Heraud, R. Gispert, K.M. Gorski, S. Gratton, M. Griffin, G. Guyot, J. Haissinski, D. Harrison, G. Helou, S. Henrot-Versille, C. Hernandez-Monteagudo, S.R. Hildebrandt, R. Hills, E. Hivon, M. Hobson, W.A. Holmes, K.M. Huffenberger, A.H. Jaffe, W.C. Jones, J. Kaplan, R. Kneissl, L. Knox, M. Kunz, G. Lagache, J.M. Lamarre, A.E. Lange, A. Lasenby, A. Lavabre, C.R. Lawrence, M. Le Jeune, C. Leroy, J. Lesgourgues, J.F. Macias-Perez, C.J. Mactavish, B. Maffei, N. Mandolesi, R. Mann, F. Marleau, D.J. Marshall, Silvia Masi, T. Matsumura, I. Mcauley, P. Mcgehee, J.B. Melin, C. Mercier, S. Mitra, M.A. Miville-Deschenes, A. Moneti, L. Montier, D. Mortlock, A. Murphy, Federico Nati, C.B. Netterfield, H.U. Nørgaard-Nielsen, H.U. Norgaard-Nielsen, C. North, F. Noviello, D. Novikov, S. Osborne, F. Pajot, G. Patanchon, T. Peacocke, T.J. Pearson, O. Perdereau, L. Perotto, Francesco Piacentini, M. Piat, S. Plaszczynski, E. Pointecouteau, N. Ponthieu, G. Prezeau, S. Prunet, J.L. Puget, W.T. Reach, M. Remazeilles, C. Renault, A. Riazuelo, I. Ristorcelli, G. Rocha, C. Rosset, G. Roudier, M. Rowan-Robinson, B. Rusholme, R. Saha, D. Santos, Giorgio Savini, B.M. Schaefer, P. Shellard, L. Spencer, J.L. Starck, V. Stolyarov, R. Stompor, R. Sudiwala, R. Sunyaev, D. Sutton, J.F. Sygnet, J.A. Tauber, C. Thum, J.P. Torre, F. Touze, M. Tristram, F. Van Leeuwen, L. Vibert, D. Vibert, L.A. Wade, B.D. Wandelt, S.D.M. White, H. Wiesemeyer, A. Woodcraft, V. Yurchenko, D. Yvon, A. Zacchei, Hfi Core Team, P, Ade, P, Aghanim, N, Ansari, R, Arnaud, M, Ashdown, M, Aumont, J, Banday, A, Bartelmann, M, Bartlett, J, Battaner, E, Benabed, K, Benoit, A, Bernard, J, Bersanelli, M, Bock, J, Bond, J, Borrill, J, Bouchet, F, Boulanger, F, Bradshaw, T, Bucher, M, Cardoso, J, Castex, G, Catalano, A, Challinor, A, Chamballu, A, Chary, R, Chen, X, Chiang, C, Church, S, Clements, D, Colley, J, Colombi, S, Couchot, F, Coulais, A, Cressiot, C, Crill, B, Crook, M, De Bernardis, P, Delabrouille, J, Delouis, J, Desert, F, Dolag, K, Dole, H, Dore, O, Douspis, M, Dunkley, J, Efstathiou, G, Filliard, C, Forni, O, Fosalba, P, Ganga, K, Giard, M, Girard, D, Giraud-Heraud, Y, Gispert, R, Gorski, K, Gratton, S, Griffin, M, Guyot, G, Haissinski, J, Harrison, D, Helou, G, Henrot-Versille, S, Hernandez-Monteagudo, C, Hildebrandt, S, Hills, R, Hivon, E, Hobson, M, Holmes, W, Huffenberger, K, Jaffe, A, Jones, W, Kaplan, J, Kneissl, R, Knox, L, Kunz, M, Lagache, G, Lamarre, J, Lange, A, Lasenby, A, Lavabre, A, Lawrence, C, Le Jeune, M, Leroy, C, Lesgourgues, J, Macias-Perez, J, Mactavish, C, Maffei, B, Mandolesi, N, Mann, R, Marleau, F, Marshall, D, Masi, S, Matsumura, T, Mcauley, I, Mcgehee, P, Melin, J, Mercier, C, Mitra, S, Miville-Deschenes, M, Moneti, A, Montier, L, Mortlock, D, Murphy, A, Nati, F, Netterfield, C, Nørgaard-Nielsen, H, Norgaard-Nielsen, H, North, C, Noviello, F, Novikov, D, Osborne, S, Pajot, F, Patanchon, G, Peacocke, T, Pearson, T, Perdereau, O, Perotto, L, Piacentini, F, Piat, M, Plaszczynski, S, Pointecouteau, E, Ponthieu, N, Prezeau, G, Prunet, S, Puget, J, Reach, W, Remazeilles, M, Renault, C, Riazuelo, A, Ristorcelli, I, Rocha, G, Rosset, C, Roudier, G, Rowan-Robinson, M, Rusholme, B, Saha, R, Santos, D, Savini, G, Schaefer, B, Shellard, P, Spencer, L, Starck, J, Stolyarov, V, Stompor, R, Sudiwala, R, Sunyaev, R, Sutton, D, Sygnet, J, Tauber, J, Thum, C, Torre, J, Touze, F, Tristram, M, Van Leeuwen, F, Vibert, L, Vibert, D, Wade, L, Wandelt, B, White, S, Wiesemeyer, H, Woodcraft, A, Yurchenko, V, Yvon, D, Zacchei, A, Planck Hfi Core Team, P.A.R. Ade, N. Aghanim, R. Ansari, M. Arnaud, M. Ashdown, J. Aumont, A.J. Banday, M. Bartelmann, J.G. Bartlett, E. Battaner, K. Benabed, A. Benoit, J.P. Bernard, M. Bersanelli, J.J. Bock, J.R. Bond, J. Borrill, F.R. Bouchet, F. Boulanger, T. Bradshaw, M. Bucher, J.F. Cardoso, G. Castex, A. Catalano, A. Challinor, A. Chamballu, R.R. Chary, X. Chen, C. Chiang, S. Church, D.L. Clements, J.M. Colley, S. Colombi, F. Couchot, A. Coulais, C. Cressiot, B.P. Crill, M. Crook, Paolo De Bernardis, J. Delabrouille, J.M. Delouis, F.X. Desert, K. Dolag, H. Dole, O. Dore, M. Douspis, J. Dunkley, G. Efstathiou, C. Filliard, O. Forni, P. Fosalba, K. Ganga, M. Giard, D. Girard, Y. Giraud-Heraud, R. Gispert, K.M. Gorski, S. Gratton, M. Griffin, G. Guyot, J. Haissinski, D. Harrison, G. Helou, S. Henrot-Versille, C. Hernandez-Monteagudo, S.R. Hildebrandt, R. Hills, E. Hivon, M. Hobson, W.A. Holmes, K.M. Huffenberger, A.H. Jaffe, W.C. Jones, J. Kaplan, R. Kneissl, L. Knox, M. Kunz, G. Lagache, J.M. Lamarre, A.E. Lange, A. Lasenby, A. Lavabre, C.R. Lawrence, M. Le Jeune, C. Leroy, J. Lesgourgues, J.F. Macias-Perez, C.J. Mactavish, B. Maffei, N. Mandolesi, R. Mann, F. Marleau, D.J. Marshall, Silvia Masi, T. Matsumura, I. Mcauley, P. Mcgehee, J.B. Melin, C. Mercier, S. Mitra, M.A. Miville-Deschenes, A. Moneti, L. Montier, D. Mortlock, A. Murphy, Federico Nati, C.B. Netterfield, H.U. Nørgaard-Nielsen, H.U. Norgaard-Nielsen, C. North, F. Noviello, D. Novikov, S. Osborne, F. Pajot, G. Patanchon, T. Peacocke, T.J. Pearson, O. Perdereau, L. Perotto, Francesco Piacentini, M. Piat, S. Plaszczynski, E. Pointecouteau, N. Ponthieu, G. Prezeau, S. Prunet, J.L. Puget, W.T. Reach, M. Remazeilles, C. Renault, A. Riazuelo, I. Ristorcelli, G. Rocha, C. Rosset, G. Roudier, M. Rowan-Robinson, B. Rusholme, R. Saha, D. Santos, Giorgio Savini, B.M. Schaefer, P. Shellard, L. Spencer, J.L. Starck, V. Stolyarov, R. Stompor, R. Sudiwala, R. Sunyaev, D. Sutton, J.F. Sygnet, J.A. Tauber, C. Thum, J.P. Torre, F. Touze, M. Tristram, F. Van Leeuwen, L. Vibert, D. Vibert, L.A. Wade, B.D. Wandelt, S.D.M. White, H. Wiesemeyer, A. Woodcraft, V. Yurchenko, D. Yvon, and A. Zacchei

Abstract

We describe the processing of the 336 billion raw data samples from the High Frequency Instrument (HFI) which we performed to produce six temperature maps from the first 295 days of Planck-HFI survey data. These maps provide an accurate rendition of the sky emission at 100, 143, 217, 353, 545 and 857GHz with an angular resolution ranging from 9.9 to 4.4'. The white noise level is around 1.5 mu K degree or less in the 3 main CMB channels (100-217 GHz). The photometric accuracy is better than 2% at frequencies between 100 and 353 GHz and around 7% at the two highest frequencies. The maps created by the HFI Data Processing Centre reach our goals in terms of sensitivity, resolution, and photometric accuracy. They are already sufficiently accurate and well-characterised to allow scientific analyses which are presented in an accompanying series of early papers. At this stage, HFI data appears to be of high quality and we expect that with further refinements of the data processing we should be able to achieve, or exceed, the science goals of the Planck project.

Published
2011

15. Planck early results. IV. First assessment of the High Frequency Instrument in-flight performance

Author

Hfi Core Team, P, Ade, P, Aghanim, N, Ansari, R, Arnaud, M, Ashdown, M, Aumont, J, Banday, A, Bartelmann, M, Bartlett, J, Battaner, E, Benabed, K, Benoit, A, Bernard, J, Bersanelli, M, Bhatia, R, Bock, J, Bond, J, Borrill, J, Bouchet, F, Boulanger, F, Bradshaw, T, Breelle, E, Bucher, M, Camus, P, Cardoso, J, Catalano, A, Challinor, A, Chamballu, A, Charra, J, Charra, M, Chary, R, Chiang, C, Church, S, Clements, D, Colombi, S, Couchot, F, Coulais, A, Cressiot, C, Crill, B, Crook, M, De Bernardis, P, Delabrouille, J, Delouis, J, Desert, F, Dolag, K, Dole, H, Dore, O, Douspis, M, Efstathiou, G, Eng, P, Filliard, C, Forni, O, Fosalba, P, Fourmond, J, Ganga, K, Giard, M, Girard, D, Giraud-Heraud, Y, Gispert, R, Gorski, K, Gratton, S, Griffin, M, Guyot, G, Haissinski, J, Harrison, D, Helou, G, Henrot-Versille, S, Hernandez-Monteagudo, C, Hildebrandt, S, Hills, R, Hivon, E, Hobson, M, Holmes, W, Huffenberger, K, Jaffe, A, Jones, W, Kaplan, J, Kneissl, R, Knox, L, Lagache, G, Lamarre, J, Lami, P, Lange, A, Lasenby, A, Lavabre, A, Lawrence, C, Leriche, B, Leroy, C, Longval, Y, Macias-Perez, J, Maciaszek, T, Mactavish, C, Maffei, B, Mandolesi, N, Mann, R, Mansoux, B, Masi, S, Matsumura, T, Mcgehee, P, Melin, J, Mercier, C, Miville-Deschenes, M, Moneti, A, Montier, L, Mortlock, D, Murphy, A, Nati, F, Netterfield, C, Norgaard-Nielsen, H, Nørgaard-Nielsen, H, North, C, Noviello, F, Novikov, D, Osborne, S, Paine, C, Pajot, F, Patanchon, G, Peacocke, T, Pearson, T, Perdereau, O, Perotto, L, Piacentini, F, Piat, M, Plaszczynski, S, Pointecouteau, E, Pons, R, Ponthieu, N, Prezeau, G, Prunet, S, Puget, J, Reach, W, Renault, C, Ristorcelli, I, Rocha, G, Rosset, C, Roudier, G, Rowan-Robinson, M, Rusholme, B, Santos, D, Savini, G, Schaefer, B, Shellard, P, Spencer, L, Starck, J, Stassi, P, Stolyarov, V, Stompor, R, Sudiwala, R, Sunyaev, R, Sygnet, J, Tauber, J, Thum, C, Torre, J, Touze, F, Tristram, M, Van Leeuwen, F, Vibert, L, Vibert, D, Wade, L, Wandelt, B, White, S, Wiesemeyer, H, Woodcraft, A, Yurchenko, V, Yvon, D, Zacchei, A, Planck Hfi Core Team, P.A.R. Ade, N. Aghanim, R. Ansari, M. Arnaud, M. Ashdown, J. Aumont, A.J. Banday, M. Bartelmann, J.G. Bartlett, E. Battaner, K. Benabed, A. Benoit, J.P. Bernard, M. Bersanelli, R. Bhatia, J.J. Bock, J.R. Bond, J. Borrill, F.R. Bouchet, F. Boulanger, T. Bradshaw, E. Breelle, M. Bucher, P. Camus, J.F. Cardoso, A. Catalano, A. Challinor, A. Chamballu, J. Charra, M. Charra, R.R. Chary, C. Chiang, S. Church, D.L. Clements, S. Colombi, F. Couchot, A. Coulais, C. Cressiot, B.P. Crill, M. Crook, Paolo De Bernardis, J. Delabrouille, J.M. Delouis, F.X. Desert, K. Dolag, H. Dole, O. Dore, M. Douspis, G. Efstathiou, P. Eng, C. Filliard, O. Forni, P. Fosalba, J.J. Fourmond, K. Ganga, M. Giard, D. Girard, Y. Giraud-Heraud, R. Gispert, K.M. Gorski, S. Gratton, M. Griffin, G. Guyot, J. Haissinski, D. Harrison, G. Helou, S. Henrot-Versille, C. Hernandez-Monteagudo, S.R. Hildebrandt, R. Hills, E. Hivon, M. Hobson, W.A. Holmes, K.M. Huffenberger, A.H. Jaffe, W.C. Jones, J. Kaplan, R. Kneissl, L. Knox, G. Lagache, J.M. Lamarre, P. Lami, A.E. Lange, A. Lasenby, A. Lavabre, C.R. Lawrence, B. Leriche, C. Leroy, Y. Longval, J.F. Macias-Perez, T. Maciaszek, C.J. Mactavish, B. Maffei, N. Mandolesi, R. Mann, B. Mansoux, Silvia Masi, T. Matsumura, P. Mcgehee, J.B. Melin, C. Mercier, M.A. Miville-Deschenes, A. Moneti, L. Montier, D. Mortlock, A. Murphy, Federico Nati, C.B. Netterfield, H.U. Norgaard-Nielsen, H.U. Nørgaard-Nielsen, C. North, F. Noviello, D. Novikov, S. Osborne, C. Paine, F. Pajot, G. Patanchon, T. Peacocke, T.J. Pearson, O. Perdereau, L. Perotto, Francesco Piacentini, M. Piat, S. Plaszczynski, E. Pointecouteau, R. Pons, N. Ponthieu, G. Prezeau, S. Prunet, J.L. Puget, W.T. Reach, C. Renault, I. Ristorcelli, G. Rocha, C. Rosset, G. Roudier, M. Rowan-Robinson, B. Rusholme, D. Santos, Giorgio Savini, B.M. Schaefer, P. Shellard, L. Spencer, J.L. Starck, P. Stassi, V. Stolyarov, R. Stompor, R. Sudiwala, R. Sunyaev, J.F. Sygnet, J.A. Tauber, C. Thum, J.P. Torre, F. Touze, M. Tristram, F. Van Leeuwen, L. Vibert, D. Vibert, L.A. Wade, B.D. Wandelt, S.D.M. White, H. Wiesemeyer, A. Woodcraft, V. Yurchenko, D. Yvon, A. Zacchei, Hfi Core Team, P, Ade, P, Aghanim, N, Ansari, R, Arnaud, M, Ashdown, M, Aumont, J, Banday, A, Bartelmann, M, Bartlett, J, Battaner, E, Benabed, K, Benoit, A, Bernard, J, Bersanelli, M, Bhatia, R, Bock, J, Bond, J, Borrill, J, Bouchet, F, Boulanger, F, Bradshaw, T, Breelle, E, Bucher, M, Camus, P, Cardoso, J, Catalano, A, Challinor, A, Chamballu, A, Charra, J, Charra, M, Chary, R, Chiang, C, Church, S, Clements, D, Colombi, S, Couchot, F, Coulais, A, Cressiot, C, Crill, B, Crook, M, De Bernardis, P, Delabrouille, J, Delouis, J, Desert, F, Dolag, K, Dole, H, Dore, O, Douspis, M, Efstathiou, G, Eng, P, Filliard, C, Forni, O, Fosalba, P, Fourmond, J, Ganga, K, Giard, M, Girard, D, Giraud-Heraud, Y, Gispert, R, Gorski, K, Gratton, S, Griffin, M, Guyot, G, Haissinski, J, Harrison, D, Helou, G, Henrot-Versille, S, Hernandez-Monteagudo, C, Hildebrandt, S, Hills, R, Hivon, E, Hobson, M, Holmes, W, Huffenberger, K, Jaffe, A, Jones, W, Kaplan, J, Kneissl, R, Knox, L, Lagache, G, Lamarre, J, Lami, P, Lange, A, Lasenby, A, Lavabre, A, Lawrence, C, Leriche, B, Leroy, C, Longval, Y, Macias-Perez, J, Maciaszek, T, Mactavish, C, Maffei, B, Mandolesi, N, Mann, R, Mansoux, B, Masi, S, Matsumura, T, Mcgehee, P, Melin, J, Mercier, C, Miville-Deschenes, M, Moneti, A, Montier, L, Mortlock, D, Murphy, A, Nati, F, Netterfield, C, Norgaard-Nielsen, H, Nørgaard-Nielsen, H, North, C, Noviello, F, Novikov, D, Osborne, S, Paine, C, Pajot, F, Patanchon, G, Peacocke, T, Pearson, T, Perdereau, O, Perotto, L, Piacentini, F, Piat, M, Plaszczynski, S, Pointecouteau, E, Pons, R, Ponthieu, N, Prezeau, G, Prunet, S, Puget, J, Reach, W, Renault, C, Ristorcelli, I, Rocha, G, Rosset, C, Roudier, G, Rowan-Robinson, M, Rusholme, B, Santos, D, Savini, G, Schaefer, B, Shellard, P, Spencer, L, Starck, J, Stassi, P, Stolyarov, V, Stompor, R, Sudiwala, R, Sunyaev, R, Sygnet, J, Tauber, J, Thum, C, Torre, J, Touze, F, Tristram, M, Van Leeuwen, F, Vibert, L, Vibert, D, Wade, L, Wandelt, B, White, S, Wiesemeyer, H, Woodcraft, A, Yurchenko, V, Yvon, D, Zacchei, A, Planck Hfi Core Team, P.A.R. Ade, N. Aghanim, R. Ansari, M. Arnaud, M. Ashdown, J. Aumont, A.J. Banday, M. Bartelmann, J.G. Bartlett, E. Battaner, K. Benabed, A. Benoit, J.P. Bernard, M. Bersanelli, R. Bhatia, J.J. Bock, J.R. Bond, J. Borrill, F.R. Bouchet, F. Boulanger, T. Bradshaw, E. Breelle, M. Bucher, P. Camus, J.F. Cardoso, A. Catalano, A. Challinor, A. Chamballu, J. Charra, M. Charra, R.R. Chary, C. Chiang, S. Church, D.L. Clements, S. Colombi, F. Couchot, A. Coulais, C. Cressiot, B.P. Crill, M. Crook, Paolo De Bernardis, J. Delabrouille, J.M. Delouis, F.X. Desert, K. Dolag, H. Dole, O. Dore, M. Douspis, G. Efstathiou, P. Eng, C. Filliard, O. Forni, P. Fosalba, J.J. Fourmond, K. Ganga, M. Giard, D. Girard, Y. Giraud-Heraud, R. Gispert, K.M. Gorski, S. Gratton, M. Griffin, G. Guyot, J. Haissinski, D. Harrison, G. Helou, S. Henrot-Versille, C. Hernandez-Monteagudo, S.R. Hildebrandt, R. Hills, E. Hivon, M. Hobson, W.A. Holmes, K.M. Huffenberger, A.H. Jaffe, W.C. Jones, J. Kaplan, R. Kneissl, L. Knox, G. Lagache, J.M. Lamarre, P. Lami, A.E. Lange, A. Lasenby, A. Lavabre, C.R. Lawrence, B. Leriche, C. Leroy, Y. Longval, J.F. Macias-Perez, T. Maciaszek, C.J. Mactavish, B. Maffei, N. Mandolesi, R. Mann, B. Mansoux, Silvia Masi, T. Matsumura, P. Mcgehee, J.B. Melin, C. Mercier, M.A. Miville-Deschenes, A. Moneti, L. Montier, D. Mortlock, A. Murphy, Federico Nati, C.B. Netterfield, H.U. Norgaard-Nielsen, H.U. Nørgaard-Nielsen, C. North, F. Noviello, D. Novikov, S. Osborne, C. Paine, F. Pajot, G. Patanchon, T. Peacocke, T.J. Pearson, O. Perdereau, L. Perotto, Francesco Piacentini, M. Piat, S. Plaszczynski, E. Pointecouteau, R. Pons, N. Ponthieu, G. Prezeau, S. Prunet, J.L. Puget, W.T. Reach, C. Renault, I. Ristorcelli, G. Rocha, C. Rosset, G. Roudier, M. Rowan-Robinson, B. Rusholme, D. Santos, Giorgio Savini, B.M. Schaefer, P. Shellard, L. Spencer, J.L. Starck, P. Stassi, V. Stolyarov, R. Stompor, R. Sudiwala, R. Sunyaev, J.F. Sygnet, J.A. Tauber, C. Thum, J.P. Torre, F. Touze, M. Tristram, F. Van Leeuwen, L. Vibert, D. Vibert, L.A. Wade, B.D. Wandelt, S.D.M. White, H. Wiesemeyer, A. Woodcraft, V. Yurchenko, D. Yvon, and A. Zacchei

Abstract

The Planck High Frequency Instrument (HFI) is designed to measure the temperature and polarization anisotropies of the cosmic microwave background and Galactic foregrounds in six ~30% bands centered at 100, 143, 217, 353, 545, and 857 GHz at an angular resolution of 10′ (100 GHz), 7′ (143 GHz), and 5′ (217 GHz and higher). HFI has been operating flawlessly since launch on 14 May 2009, with the bolometers reaching 100 mK the first week of July. The settings of the readout electronics, including bolometer bias currents, that optimize HFI's noise performance on orbit are nearly the same as the ones chosen during ground testing. Observations of Mars, Jupiter, and Saturn have confirmed that the optical beams and the time responses of the detection chains are in good agreement with the predictions of physical optics modeling and pre-launch measurements. The Detectors suffer from a high flux of cosmic rays due to historically low levels of solar activity. As a result of the redundancy of Planck's observation strategy, theremoval of a few percent of data contaminated by glitches does not significantly affect the instrumental sensitivity. The cosmic ray flux represents a significant and variable heat load on the sub-Kelvin stage. Temporal variation and the inhomogeneous distribution of the flux results in thermal fluctuations that are a probable source of low frequency noise. The removal of systematic effects in the time ordered data provides a signal with an average noise equivalent power that is 70% of the goal in the 0.6-2.5 Hz range. This is slightly higher than was achieved during the pre-launch characterization but better than predicted in the early phases of the project. The improvement over the goal is a result of the low level of instrumental background loading achieved by the optical and thermal design of the HFI.

Published
2011

16. A Square Degree Survey for Molecular Flows in TMC1

Author

F. Gueth, K. F. Schuster, H. Ungerechts, M. Sterzik, H. Wiesemeyer, B. Lefloch, and Clemens Thum

Subjects
Physics, Free molecular flow, Scale (ratio), Star formation, Young stellar object, Optical polarization, Geometry, Area density, Line (formation), Computational physics, Square degree
Abstract

We conducted a high-sensitivity high-resolution survey in the 230 GHz CO(2-1) line throughout a major fraction of the TMC1 complex (Heiles cloud 2) to search for molecular flows from young stellar objects. Our observations show a large number of unknown flows from known or unknown objects. The flows have a wide range of morphologies on scale sizes from 0.01 to 1 pc. A first analysis suggests an alignment among flows in parallel to magnetic fields as derived from optical polarization measurements. The area density of flows is sufficiently high to suggest an important impact on the cloud and the star formation within.

Published
1997
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17. Atomic and Molecular Gas in M17 SW

Author

R. Gusten, H. Wiesemeyer, J. Stutzki, V. Ossenkopf, and J. P. Pérez-Beaupuits

Subjects
Materials science, Space and Planetary Science, Astronomy and Astrophysics
Abstract

We probe the spatial distribution of the [C ii] μm fine-structure emission and its association with neutral and molecular gas in a 5′.7 × 3′.7 (∼3.3 × 2.1 pc2) region of the M17 SW nebula. Comparison of velocity-resolved [C ii] emission maps with other atomic and molecular tracers is possible for the first time with the dual band receiver GREAT on board the SOFIA airborne telescope. We detected [C ii] emission in a much broader velocity range than the CO-lines (Pérez-Beaupuits et al. 2012). Only [C ii] narrow channel maps at intermediate velocities (between 10 and 24 kms) show correlations with other molecular gas components, supporting a clumpy cloud scenario. At lower (< 10 kms) and higher (>24 kms) velocities instead, we see more than 60% of the region mapped in [C ii] that is not associated with other tracers of star-forming material, the so called “CO-dark” gas. Interaction with winds and outflows lead to substantial excitation of [C ii] emitting gas, so that ablation and shock-interaction have to be taken into account to model the observed [C ii] emission.

Published
2012
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18. Velocity-resolved [O i] 63 μm Emission in the HD 50138 Circumstellar Disk.

Author

Göran Sandell, C. Salyk, M. van den Ancker, W.-J. de Wit, E. Chambers, R. Güsten, H. Wiesemeyer, and H. Richter

Subjects
VELOCITY, EMISSIONS (Air pollution), INTERFEROMETRY, IONIZED gases, A stars, STELLAR magnitudes
Abstract

HD 50138 is one of the brightest B[e] stars and is located at a distance of ∼380 pc with strong infrared excess. The star was observed in [O i] 63 μm and [C ii] 158 μm with high velocity resolution with upGREAT on SOFIA. The velocity-resolved [O i] emission provides evidence for a large gas disk, ∼760 au in size, around HD 50138. Whereas previous interferometric observations gave strong evidence for a hot gas and dust disk in Keplerian rotation, our observations are the first to provide unambiguous evidence for a large warm disk around the star. Herschel/PACS observations showed that the [C ii] emission is extended, therefore the [C ii] emission most likely originates from an ionized gas shell created by a past outflow event. We confirm the isolated nature of HD 50138. It is far from any star-forming region and has low proper motion. Neither is there any sign of a remnant cloud from which it could have formed. The extended disk around the star appears to be carbon-poor. It shows OH and [O i] emission, but no CO. The CO abundance appears to be at least an order of magnitude lower than that of OH. Furthermore, 13CO is enriched by more than a factor of five, confirming that the star is not a Herbig Be star. Finally, we note that our high-spectral-resolution [O i] and [C ii] observations provide a very accurate heliocentric velocity of the star, 40.8 ± 0.2 km s−1. [ABSTRACT FROM AUTHOR]

Published
2018
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19. Direct detection of atomic oxygen on the dayside and nightside of Venus.

Author

Hübers HW, Richter H, Graf UU, Güsten R, Klein B, Stutzki J, and Wiesemeyer H

Abstract

Atomic oxygen is a key species in the mesosphere and thermosphere of Venus. It peaks in the transition region between the two dominant atmospheric circulation patterns, the retrograde super-rotating zonal flow below 70 km and the subsolar to antisolar flow above 120 km altitude. However, past and current detection methods are indirect and based on measurements of other molecules in combination with photochemical models. Here, we show direct detection of atomic oxygen on the dayside as well as on the nightside of Venus by measuring its ground-state transition at 4.74 THz (63.2 µm). The atomic oxygen is concentrated at altitudes around 100 km with a maximum column density on the dayside where it is generated by photolysis of carbon dioxide and carbon monoxide. This method enables detailed investigations of the Venusian atmosphere in the region between the two atmospheric circulation patterns in support of future space missions to Venus., (© 2023. The Author(s).)

Published
2023
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20. Astrophysical detection of the helium hydride ion HeH .

Author

Güsten R, Wiesemeyer H, Neufeld D, Menten KM, Graf UU, Jacobs K, Klein B, Ricken O, Risacher C, and Stutzki J

Abstract

During the dawn of chemistry 1,2 , when the temperature of the young Universe had fallen below some 4,000 kelvin, the ions of the light elements produced in Big Bang nucleosynthesis recombined in reverse order of their ionization potential. With their higher ionization potentials, the helium ions He 2+ and He + were the first to combine with free electrons, forming the first neutral atoms; the recombination of hydrogen followed. In this metal-free and low-density environment, neutral helium atoms formed the Universe's first molecular bond in the helium hydride ion HeH + through radiative association with protons. As recombination progressed, the destruction of HeH + created a path to the formation of molecular hydrogen. Despite its unquestioned importance in the evolution of the early Universe, the HeH + ion has so far eluded unequivocal detection in interstellar space. In the laboratory the ion was discovered 3 as long ago as 1925, but only in the late 1970s was the possibility that HeH + might exist in local astrophysical plasmas discussed 4-7 . In particular, the conditions in planetary nebulae were shown to be suitable for producing potentially detectable column densities of HeH + . Here we report observations, based on advances in terahertz spectroscopy 8,9 and a high-altitude observatory 10 , of the rotational ground-state transition of HeH + at a wavelength of 149.1 micrometres in the planetary nebula NGC 7027. This confirmation of the existence of HeH + in nearby interstellar space constrains our understanding of the chemical networks that control the formation of this molecular ion, in particular the rates of radiative association and dissociative recombination.

Published
2019
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