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31 results on '"A. O. H. Olofsson"'

1. The shocked molecular layer in RCW 120

Author

M S Kirsanova, Ya N Pavlyuchenkov, A O H Olofsson, D A Semenov, and A F Punanova

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

Expansion of wind-blown bubbles or HII regions lead to formation of shocks in the interstellar medium, which compress surrounding gas into dense layers. We made spatially and velocity-resolved observations of the RCW~120 PDR and nearby molecular gas with CO(6-5) and 13CO(6-5) lines and distinguished a bright CO-emitting layer, which we related with the dense shocked molecular gas moving away from the ionizing star due to expansion of HII region. Simulating gas density and temperature, as well as brightness of several CO and C+ emission lines from the PDR, we found reasonable agreement with the observed values. Analysing gas kinematics, we revealed the large-scale shocked PDR and also several dense environments of embedded protostars and outflows. We observe the shocked layer as the most regular structure in the CO(6-5) map and in the velocity space, when the gas around YSOs is dispersed by the outflows., accepted for publication in MNRAS

Published
2022

2. Hunting for the elusive methylene radical

Author

Y. Gong, Sandra Brünken, Per Bergman, M. Tiwari, Karl M. Menten, A. O. H. Olofsson, and Arshia M. Jacob

Subjects
Physics, Molecular cloud, FOS: Physical sciences, Astronomy and Astrophysics, Context (language use), Astrophysics, FELIX Infrared and Terahertz Spectroscopy, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, law.invention, Telescope, Stars, Far infrared, Space and Planetary Science, law, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Radiative transfer, 010306 general physics, 010303 astronomy & astrophysics, Hyperfine structure, Line (formation)
Abstract

CH2 transitions between 68 and 71 GHz were first detected toward the Orion-KL and W51 Main SFRs. Given their upper level energies of 225 K, they were thought to arise in dense, hot molecular cores near newly formed stars. However, this has not been confirmed by further observations of these lines and their origin has remained unclear. Generally, there is a scarcity of observational data for CH2 and, while it is an important compound in the astrochemical context, its actual occurrence in astronomical sources is poorly constrained. The present study, along with other recent observations of the Orion region we report, rule out the possibility of an association with gas that is both hot and dense. We find that the distribution of the CH2 emission closely follows that of the [CII] 158 um emission, while CH2 is undetected toward the hot core itself. The observations suggest, rather, that its extended emission arises from hot but dilute layers of PDRs and not from the denser parts of such regions as in the case of the Orion Bar. This hypothesis was corroborated by comparisons of the observed CH2 line profiles with those of CRRLs, well-known PDR tracers. In addition, we report the detection of the 70 GHz fine- and hfs lines of o-CH2 toward the W51E, W51M, W51N, W49N, W43, W75N, DR21, and S140 SFRs, and three of the fine- and hfs lines between 68-71 GHz toward W3 IRS5. Furthermore, using a non-LTE radiative transfer analysis, we can constrain the gas temperatures and H2 density to 163 K and 3.4e3 cm^-3, respectively. This analysis confirms our hypothesis that CH2 originates in warm and dilute PDR layers. Our analysis suggests that for the excitation conditions under the physical conditions that prevail in such regions, these lines are masering, with weak level inversion. The resulting amplification of the lines' spontaneous emission greatly aids in their detection., Accepted in A&A, 25 pages, 18 figures, 5 tables

Published
2021

3. The TOI-763 system: sub-Neptunes orbiting a Sun-like star

Author

Enric Palle, Jon M. Jenkins, Vincent Van Eylen, Seth Redfield, Coel Hellier, Simon Albrecht, Oscar Barragán, Martin Pätzold, William D. Cochran, Emanuela Pompei, Roland Vanderspek, Judith Korth, George R. Ricker, Norio Narita, L. M. Serrano, John H. Livingston, Sascha Grziwa, Eike W. Guenther, Fei Dai, S. E. Mullally, S. Villanueva, Eric B. Ting, K. W. F. Lam, Andrew Vanderburg, Rafael Luque, Alexis M. S. Smith, Carina M. Persson, M. Esposito, Teriyuki Hirano, Malcolm Fridlund, P. Tenenbaum, Hans J. Deeg, Florian Rodler, Joshua N. Winn, Serena Benatti, Davide Gandolfi, Szilard Csizmadia, Luke G. Bouma, Emil Knudstrup, Lorenzo Spina, A. P. Hatzes, J. Cabrera, Savita Mathur, Grzegorz Nowak, Keivan G. Stassun, David W. Latham, Sara Seager, Luca Malavolta, Heike Rauer, L. González Cuesta, Jan Subjak, A. O. H. Olofsson, Petr Kabath, and Iskra Georgieva

Subjects
Extrasolare Planeten und Atmosphären, planets and satellites: individual: TIC 178819686, Dwarf star, planets and satellites: detection, Proper motion, detection [planets and satellites], Metallicity, planets and satellites: individual: TOI-763, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 010309 optics, individual: TIC 178819686 [planets and satellites], Planet, QB460, 0103 physical sciences, 010303 astronomy & astrophysics, QB600, QC, individual: TOI-763 [planets and satellites], QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Leitungsbereich PF, Astronomy, Astronomy and Astrophysics, Planetary system, Orbital period, Light curve, Radial velocity, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

We report the discovery of a planetary system orbiting TOI-763 (aka CD-39 7945), a $V=10.2$, high proper motion G-type dwarf star that was photometrically monitored by the TESS space mission in Sector 10. We obtain and model the stellar spectrum and find an object slightly smaller than the Sun, and somewhat older, but with a similar metallicity. Two planet candidates were found in the light curve to be transiting the star. Combining TESS transit photometry with HARPS high-precision radial velocity follow-up measurements confirm the planetary nature of these transit signals. We determine masses, radii, and bulk densities of these two planets. A third planet candidate was discovered serendipitously in the radial velocity data. The inner transiting planet,TOI-763 b, has an orbital period of $P_\mathrm{b}$ = 5.6~days, a mass of $M_\mathrm{b}$ = $9.8\pm0.8$ $M_\oplus$, and a radius of $R_\mathrm{b}$ = $2.37\pm0.10$ $R_\oplus$. The second transiting planet,TOI-763 c, has an orbital period of $P_\mathrm{c}$ = 12.3~days, a mass of $M_\mathrm{c}$ = $9.3\pm1.0$ $M_\oplus$, and a radius of $R_\mathrm{c}$ = $2.87\pm0.11$ $R_\oplus$. We find the outermost planet candidate to orbit the star with a period of $\sim$48~days. If confirmed as a planet it would have a minimum mass of $M_\mathrm{d}$ = $9.5\pm1.6$ $M_\oplus$. We investigated the TESS light curve in order to search for a mono transit by planet~d without success. We discuss the importance and implications of this planetary system in terms of the geometrical arrangements of planets orbiting G-type stars.

Published
2020
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4. Water and ammonia abundances in S140 with the Odin satellite

Author

A. O. H. Olofsson, Aa. Sandqvist, Carina M. Persson, Marco Spaans, T. Liljestrom, Åke Hjalmarson, D. R. Poelman, John H. Black, Urban Frisk, Michael Olberg, and Astronomy

Subjects
WAVE-ASTRONOMY-SATELLITE, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astrophysics, PHOTON-DOMINATED REGION, GAS-PHASE H2O, 1ST DETECTION, MASSIVE PROTOSTARS, MOLECULAR CLOUD, 01 natural sciences, ISM: abundances, Ammonia, chemistry.chemical_compound, Abundance (ecology), 0103 physical sciences, submillimeter, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Line (formation), Physics, STAR-FORMING REGIONS, SPECTRAL-LINE SURVEY, Astronomy and Astrophysics, line: profiles, Line width, ISM: molecules, ORION-KL, BANDS 486-492, chemistry, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Homogeneous, ISM: individual objects: S140, Outflow, Satellite, line: formation, Intensity (heat transfer)
Abstract

We have used the Odin satellite to obtain strip maps of the ground-state rotational transitions of ortho-water and ortho-ammonia, as well as CO(5-4) and 13CO(5-4) across the PDR, and H218O in the central position. A physi-chemical inhomogeneous PDR model was used to compute the temperature and abundance distributions for water, ammonia and CO. A multi-zone escape probability method then calculated the level populations and intensity distributions. These results are compared to a homogeneous model computed with an enhanced version of the RADEX code. H2O, NH3 and 13CO show emission from an extended PDR with a narrow line width of ~3 kms. Like CO, the water line profile is dominated by outflow emission, however, mainly in the red wing. The PDR model suggests that the water emission mainly arises from the surfaces of optically thick, high density clumps with n(H2)>10^6 cm^-3 and a clump water abundance, with respect to H2, of 5x10^-8. The mean water abundance in the PDR is 5x10^-9, and between ~2x10^-8 -- 2x10^-7 in the outflow derived from a simple two-level approximation. Ammonia is also observed in the extended clumpy PDR, likely from the same high density and warm clumps as water. The average ammonia abundance is about the same as for water: 4x10^-9 and 8x10^-9 given by the PDR model and RADEX, respectively. The similarity of water and ammonia PDR emission is also seen in the almost identical line profiles observed close to the bright rim. Around the central position, ammonia also shows some outflow emission although weaker than water in the red wing. Predictions of the H2O(110-101) and (111-000) antenna temperatures across the PDR are estimated with our PDR model for the forthcoming observations with the Herschel Space Observatory., 13 pages, 14 figures, 10 tables. Accepted for publication in Astronomy & Astrophysics 14 November 2008

Published
2009
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5. Characterization of a dense aperture array for radio astronomy

Author

C. Taffoureau, B. Censier, Aris Karastergiou, P. Picard, P. Renaud, A. O. H. Olofsson, Steve Torchinsky, M. Serylak, Unité Scientifique de la Station de Nançay (USN), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université d'Orléans (UO), Onsala Space Observatory (OSO), Chalmers University of Technology [Göteborg], Oxford Astrophysics, University of Oxford [Oxford], SKA South Africa, Department of Physics and Astronomy [South Africa], and University of the Western Cape

Subjects
Aperture array, Aperture, Computer science, FOS: Physical sciences, 02 engineering and technology, 01 natural sciences, Optics, Techniques: radio astronomy, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Calibration, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Large field of view, business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, 020206 networking & telecommunications, Astronomy and Astrophysics, Characterization (materials science), [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Square Kilometre Array, Square kilometre array, Space and Planetary Science, Instrumentation: interferometers, Antenna (radio), business, Astrophysics - Instrumentation and Methods for Astrophysics, Radio astronomy
Abstract

EMBRACE@Nancay is a prototype instrument consisting of an array of 4608 densely packed antenna elements creating a fully sampled, unblocked aperture. This technology is proposed for the Square Kilometre Array and has the potential of providing an extremely large field of view making it the ideal survey instrument. We describe the system,calibration procedures, and results from the prototype., 17 pages, accepted for publication in A&A

Published
2016
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6. NIBLES: An H I census of stellar mass selected SDSS galaxies. I. The Nançay H I survey

Author

Stephen E. Schneider, T. Joseph, M. D. Lehnert, A. O. H. Olofsson, P. Kotze, N. Hallet, M. Ramatsoku, R. C. Kraan-Korteweg, L. Chemin, S. L. Blyth, W. van Driel, Robert F. Minchin, Z. Butcher, Astronomy, Unité Scientifique de la Station de Nançay (USN), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO), Galaxies, Etoiles, Physique, Instrumentation (GEPI), 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), Bluestar Silicones, BLUESTAR SILICONES, M2A 2016, 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 de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Region Centre in France

Subjects
Physics, radio lines: galaxies, Stellar mass, 010308 nuclear & particles physics, media_common.quotation_subject, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, galaxies: general, Galaxy, Spectral line, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Photometry (optics), Radio telescope, Baryon, galaxies: photometry, Space and Planetary Science, Sky, 0103 physical sciences, Detection rate, galaxies: distances and redshifts, 010303 astronomy & astrophysics, galaxies: ISM, media_common
Abstract

To investigate galaxy properties as a function of their total stellar mass, we obtained 21cm HI line observations at the 100-m class Nan\c{c}ay Radio Telescope of 2839 galaxies from the Sloan Digital Sky Survey (SDSS) in the Local Volume (900, Comment: 71 pages, 14 figures

Published
2016
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7. Ortho-to-para ratio of NH2. Herschel-HIFI observations of ortho- and para-NH2 rotational transitions towards W31C, W49N, W51 and G34.3+0.1

Author

P. Hily-Blant, A. O. H. Olofsson, Friedrich Wyrowski, Alexandre Faure, E. Herbst, George E. Hassel, Maryvonne Gerin, Carina M. Persson, D. C. Lis, R. Le Gal, Michael Olberg, John H. Black, and Eva Wirström

Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO), Astrochemistry, FOS: Physical sciences, Astrophysics, 010402 general chemistry, 01 natural sciences, 7. Clean energy, Protein filament, chemistry.chemical_compound, 0103 physical sciences, Radiative transfer, 010303 astronomy & astrophysics, Physics, Amidogen, Order (ring theory), Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, 0104 chemical sciences, chemistry, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Excited state, Atomic physics, Ground state, Excitation, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We have used the Herschel-HIFI instrument to observe both nuclear spin symmetries of amidogen (NH2) towards the high-mass star-forming regions W31C (G10.6-0.4), W49N (G43.2-0.1), W51 (G49.5-0.4) and G34.3+0.1. The aim is to investigate the ratio of nuclear spin types, the ortho-to-para ratio (OPR), of NH2. The excited NH2 transitions are used to construct radiative transfer models of the hot cores and surrounding envelopes in order to investigate the excitation and possible emission of the ground state rotational transitions of ortho-NH2 N_(K_a,K_c} J=1_(1,1) 3/2 - 0_(0,0) 1/2 and para-NH2 2_(1,2) 5/2 - 1_(0,1) 3/2$ used in the OPR calculations. Our best estimate of the average OPR in the envelopes lie above the high temperature limit of three for W49N, specifically 3.5 with formal errors of \pm0.1, but for W31C, W51, and G34.3+0.1 we find lower values of 2.5\pm0.1, 2.7\pm0.1, and 2.3\pm0.1, respectively. Such low values are strictly forbidden in thermodynamical equilibrium since the OPR is expected to increase above three at low temperatures. In the translucent interstellar gas towards W31C, where the excitation effects are low, we find similar values between 2.2\pm0.2 and 2.9\pm0.2. In contrast, we find an OPR of 3.4\pm0.1 in the dense and cold filament connected to W51, and also two lower limits of >4.2 and >5.0 in two other translucent gas components towards W31C and W49N. At low temperatures (T \lesssim 50 K) the OPR of H2 is 20-25 K, depending on time, and values above three at lower temperatures., 21 pages, 23 figures. Accepted by Astronomy and Astrophysics 30 Nov 2015

Published
2015

8. Odin spectral line observations of Sgr A and Sgr B2 at submm wavelengths and in the 118-GHz band

Author

Aa Sandqvist, P Bergman, P Bernath, U Frisk, Å Hjalmarson, B Larsson, M Lindqvist, M Olberg, A O H Olofsson, L Pagani, and the Odin Team

Subjects
Physics, History, Wavelength, Star formation, Astronomy, Satellite, Astrophysics, Absorption (electromagnetic radiation), Spectral line, Computer Science Applications, Education, Line (formation)
Abstract

Since its launch in 2001, the Odin satellite has been observing the Galactic Centre Sgr A Complex (CND, +20 and +50 km s �1 Clouds) as well as the nearby star formation region, Sgr B2, a number of times. Observations have been made in the 118-119 GHz and 486-581 GHz bands. A limited mapping of the Sgr A Complex in the H 16 O line has been performed and new observations of the H 18 O line took place in 2006. In the 118-119 GHz band, a strong line of HC3 N( J =1 3� 12) has been detected at a number of positions - sensitive upper limits have been obtained for the O2 (11 � 10 )a nd the SiC ( 3 Π2,J =3 � 2) lines. Towards Sgr B2, submm observations have yielded absorption profiles of H 16 O, H 18 O, H 17 O, NH3 ,a nd 15 NH3.

Published
2006
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9. Odin CO and $\mathsf{^{13}}$CO J = 5–4 mapping of Orion KL – a step towards accurate water abundances

Author

Eva Wirström, Michael Olberg, A. O. H. Olofsson, Per Bergman, Aa. Sandqvist, Carina M. Persson, Åke Hjalmarson, and Urban Frisk

Subjects
Physics, Brightness, Molecular cloud, Astronomy and Astrophysics, Astrophysics, law.invention, Telescope, Full width at half maximum, Space and Planetary Science, law, Brightness temperature, Radiative transfer, Emission spectrum, Line (formation)
Abstract

Aims. The very high main beam efficiency (90%) of the telescope on the sub-millimetre wave satellite Odin, in combination with the small calibration errors in the absence of atmospheric attenuation, assures that observed line brightness temperatures are very accurately determined. Based on this, we attempt to determine the column density distribution of H-2, and the ortho-water abundance, in the Orion KL region. Methods. We have, for the first time, mapped the (CO)-C-12 J = 5-4 emission in a 7' x 7' region covering Orion KL, observed simultaneously with a (CO)-C-13 J = 5-4 map. Also presented are (CO)-O-18 J = 5-4 emission data at four different positions and a (CO)-O-17 J = 5-4 emission spectrum detected towards the Orion KL position. The Odin mapping was performed at 1' spacing ( beam full width at half maximum 126'' at 557 GHz). Results. The CO J = 5-4 narrow line emission from this region mainly arises in the warm, dense gas at the interface ( the photon-dominated region) between the M42 HII region and the Orion A molecular cloud, the Orion PDR. The (CO)-C-12 and (CO)-C-13 J = 5-4 emission maps have been used to determine the column density distribution of H-2 gas across the Orion KL region. The results have been verified by comparing to column densities obtained using the decidedly optically thin (CO)-O-18 emission as input to the RADEX radiative transfer code. We find H-2 column densities ranging from 5 x 10(21) cm(-2) at map edges to 7 x 10(22) cm(-2) at the molecular ridge. The mass of the gas in the mapped region is estimated to be 480 M-circle dot, of which 320 M-circle dot is situated towards the molecular ridge. We estimate that about half of this mass belongs to the warm Orion PDR interface layer. Finally, based on data from the positions where (CO)-O-18 J = 5-4 has been observed, we estimate the ortho-water abundance in the Orion PDR layer to be >= 8 x 10(-8), higher than previously estimated.

Published
2006
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10. The Odin satellite - II. Radiometer data processing and calibration

Author

Åke Hjalmarson, Alain Lecacheux, Steve Torchinsky, Urban Frisk, A. O. H. Olofsson, G. Florin, Michael Olberg, Philippe Baron, David Teyssier, Bengt Larsson, Kevin Volk, Aa. Sandqvist, Donal P. Murtagh, Laurent Pagani, Per Bergman, G. Olofsson, 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), Ingénieurs, Techniciens et Administratifs, 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, Physique des plasmas, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 de Cergy Pontoise (UCP), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Data processing, Radiometer, Astronomy and Astrophysics, telescopes, techniques : spectroscopic, [SDU]Sciences of the Universe [physics], Space and Planetary Science, Calibration, Satellite, submillimeter, Fixed frequency, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], space vehicles : instruments, Remote sensing
Abstract

The radiometer on-board the Odin satellite comprises four different sub-mm receivers covering the 486 - 581 GHz frequency range and one fixed frequency 119 GHz receiver. Two auto-correlators and one acousto-optical spectrometer serve as backends. This article gives an overview over the processing of the data delivered by these instruments and discusses calibration issues.

Published
2003
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11. Observations of water in comets with Odin

Author

Aa. Sandqvist, G. Serra, Nicolas Biver, Pierre Encrenaz, Philippe Baron, Steve Torchinsky, Kalevi Mattila, Sun Kwok, A. O. H. Olofsson, Michael Olberg, Kevin Volk, Jacques Crovisier, Alain Lecacheux, Roy Booth, Hans Rickman, H. G. Floren, Dominique Bockelée-Morvan, Urban Frisk, L. Nordh, F. von Schéele, Anders Winnberg, Åke Hjalmarson, 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), Ingénieurs, Techniciens et Administratifs, 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, Physique des plasmas, Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-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 Paris Cité (UPCité)

Subjects
Physics, 010308 nuclear & particles physics, Comet, Astronomy, Astronomy and Astrophysics, Coma (optics), Astrophysics, 01 natural sciences, Outgassing, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, 0103 physical sciences, Satellite, Spectral resolution, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Anisotropy, 010303 astronomy & astrophysics, Optical depth, Line (formation)
Abstract

The Odin satellite, which can observe the 1 1 0 -1 0 1 rotational line at 557 GHz of ortho water with a high spectral resolution (80 m s - 1 ) and a spatial resolution of 2.1', is well suited for cometary studies. The intensity of this line provides an estimate of the water production rate. The line width gives a direct measure of the coma expansion velocity. The line centre position and shape are affected by the anisotropy of the outgassing and by optical depth effects. Comets observed with Odin up to now are C/2001 A2 (LINEAR) during the commissioning phase of the satellite, 19P/Borrelly at the time of the Deep Space 1 flyby, C/2000 WM 1 (LINEAR), and 153P/2002 Cl (Ikeya-Zhang). For this last comet, thorough observations were made at the moment of its closest approach to Earth at the end of April 2002. A deep integration resulted in the detection of the 1 1 0 -1 0 1 line of H 2 1 8 O at 548 GHz. No 1 6 O/ 1 8 O isotopic anomaly is found.

Published
2003
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12. Low upper limits on the O2abundance from the Odin satellite

Author

George F. Mitchell, Nicholas F. H Tothill, G. Serra, Roy Booth, Kalevi Mattila, T. Liljeström, Bengt Larsson, P. A. Feldman, Christine D. Wilson, Per Bergman, Pierre Encrenaz, Michael Lindqvist, F. von Schéele, John H. Black, Maryvonne Gerin, Edith Falgarone, L. Nordh, G. Olofsson, E. M. Gregersen, René Liseau, L. E. B. Johansson, Michael Olberg, I. Ristorcelli, Sun Kwok, Jacques Crovisier, Åke Hjalmarson, Urban Frisk, Kevin Volk, V. Buat, Alain Lecacheux, Aa. Sandqvist, H. G. Floren, Peter F. Bernath, Michel Fich, A. O. H. Olofsson, Tatsuhiko I. Hasegawa, Laurent Pagani, Tommy Wiklind, Jorma Harju, Charles L. Curry, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), 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), Physique des plasmas, 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, Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-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 Paris Cité (UPCité)

Subjects
Physics, 010308 nuclear & particles physics, Astronomy, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Galaxy, Space and Planetary Science, Abundance (ecology), 0103 physical sciences, Satellite, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Ground state, 010303 astronomy & astrophysics
Abstract

For the first time, a search has been conducted in our Galaxy for the 119 GHz transition connecting to the ground state of O2, using the Odin satellite. Equipped with a sensitive 3 mm receiver (Tsy ...

Published
2003
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13. The Odin satellite

Author

U. Frisk, M. Hagström, J. Ala-Laurinaho, S. Andersson, J.-C. Berges, J.-P. Chabaud, M. Dahlgren, A. Emrich, H.-G. Florén, G. Florin, M. Fredrixon, T. Gaier, R. Haas, T. Hirvonen, Å. Hjalmarsson, B. Jakobsson, P. Jukkala, P. S. Kildal, E. Kollberg, J. Lassing, A. Lecacheux, P. Lehikoinen, A. Lehto, J. Mallat, C. Marty, D. Michet, J. Narbonne, M. Nexon, M. Olberg, A. O. H. Olofsson, G. Olofsson, A. Origné, M. Petersson, P. Piironen, R. Pons, D. Pouliquen, I. Ristorcelli, C. Rosolen, G. Rouaix, A. V. Räisänen, G. Serra, F. Sjöberg, L. Stenmark, S. Torchinsky, J. Tuovinen, C. Ullberg, E. Vinterhav, N. Wadefalk, H. Zirath, P. Zimmermann, R. Zimmermann, 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), Physique des plasmas, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
Physics, Heterodyne, Radiometer, Astronomy and Astrophysics, law.invention, Telescope, [SDU]Sciences of the Universe [physics], Space and Planetary Science, law, Extremely high frequency, Calibration, Satellite, Millimeter, Spectral resolution, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Remote sensing
Abstract

The Sub-millimetre and Millimetre Radiometer (SMR) is the main instrument on the Swedish, Canadian, Finnish and French spacecraft Odin. It consists of a 1.1 metre diameter telescope with four tuneable heterodyne receivers covering the ranges 486-504 GHz and 541-581 GHz, and one fixed at 118.75 GHz together with backends that provide spectral resolution from 150 kHz to 1 MHz. This Letter describes the Odin radiometer, its operation and performance with the data processing and calibration described in Paper II.

Published
2003
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14. On the accretion process in a high-mass star forming region - A multitransitional THz Herschel-HIFI study of ammonia toward G34.26+0.15

Author

John H. Black, Audrey Coutens, Carina M. Persson, Karl M. Menten, Michael Olberg, M. Hajigholi, Per Bergman, Åke Hjalmarson, Eva Wirström, A. O. H. Olofsson, and Friedrich Wyrowski

Subjects
Physics, 010308 nuclear & particles physics, Terahertz radiation, Star formation, Inverse, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Lambda, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Astrophysics - Solar and Stellar Astrophysics, Radiation pressure, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Radiative transfer, Outflow, 010303 astronomy & astrophysics, Excitation, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

[Abridged] Our aim is to explore the gas dynamics and the accretion process in the early phase of high-mass star formation. The inward motion of molecular gas in the massive star forming region G34.26+0.15 is investigated by using high-resolution profiles of seven transitions of ammonia at THz frequencies observed with Herschel-HIFI. The shapes and intensities of these lines are interpreted in terms of radiative transfer models of a spherical, collapsing molecular envelope. An accelerated Lambda Iteration (ALI) method is used to compute the models. The seven ammonia lines show mixed absorption and emission with inverse P-Cygni-type profiles that suggest infall onto the central source. A trend toward absorption at increasingly higher velocities for higher excitation transitions is clearly seen in the line profiles. The $J = 3\leftarrow2$ lines show only very weak emission, so these absorption profiles can be used directly to analyze the inward motion of the gas. This is the first time a multitransitional study of spectrally resolved rotational ammonia lines has been used for this purpose. Broad emission is, in addition, mixed with the absorption in the $1_0-0_0$ ortho-NH$_3$ line, possibly tracing a molecular outflow from the star forming region. The best-fitting ALI model reproduces the continuum fluxes and line profiles, but slightly underpredicts the emission and absorption depth in the ground-state ortho line $1_0-0_0$. The derived ortho-to-para ratio is approximately 0.5 throughout the infalling cloud core similar to recent findings for translucent clouds in sight lines toward W31C and W49N. We find evidence of two gas components moving inwards toward the central region with constant velocities: 2.7 and 5.3 km$\,$s$^{-1}$, relative to the source systemic velocity. The inferred mass accretion rates derived are sufficient to overcome the expected radiation pressure from G34.26+0.15., Comment: 20 pages, 18 figures, accepted by A&A 3 October 2015

Published
2015
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15. EMBRACE@Nancay: an ultra wide field of view prototype for the SKA

Author

P. Renaud, C. Taffoureau, B. Censier, A. O. H. Olofsson, Steve Torchinsky, Aris Karastergiou, M. Serylak, Unité Scientifique de la Station de Nançay (USN), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO), Onsala Space Observatory (OSO), Chalmers University of Technology [Göteborg], Oxford Astrophysics, University of Oxford [Oxford], Department of Physics and Astronomy [South Africa], University of the Western Cape, Department of Physics-Electronics, Rhodes University, Grahamstown, Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES)

Subjects
[PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Instrument optimisation, Computer science, media_common.quotation_subject, FOS: Physical sciences, Field of view, 02 engineering and technology, Astrophysics::Cosmology and Extragalactic Astrophysics, radio astronomy, 01 natural sciences, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Angular resolution, Instrumental noise, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Instrumentation, Mathematical Physics, media_common, Radio equipment, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, 020206 networking & telecommunications, interferometry, Galaxy, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Interferometry, Square Kilometre Array, Sky, Antennas, Baryon acoustic oscillations, Astrophysics - Instrumentation and Methods for Astrophysics, Radio astronomy
Abstract

A revolution in radio receiving technology is underway with the development of densely packed phased arrays for radio astronomy. This technology can provide an exceptionally large field of view, while at the same time sampling the sky with high angular resolution. Such an instrument, with a field of view of over 100 square degrees, is ideal for performing fast, all-sky, surveys, such as the "intensity mapping" experiment to measure the signature of Baryonic Acoustic Oscillations in the HI mass distribution at cosmological redshifts. The SKA, built with this technology, will be able to do a billion galaxy survey. I will present a very brief introduction to radio interferometry, as well as an overview of the Square Kilometre Array project. This will be followed by a description of the EMBRACE prototype and a discussion of results and future plans., Comment: to appear in proceedings of the INFIERI Summer School INtelligent Signal Processing for FrontIEr Research and Industry, Paris 2014

Published
2014
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16. Upper limits to interstellar NH+ and para-NH2- abundances. Herschel-HIFI observations towards Sgr B2 (M) and G10.6-0.4 (W31C)

Author

E. Herbst, Michael Olberg, A. O. H. Olofsson, Eva Wirström, George E. Hassel, Herma M. Cuppen, John H. Black, Karl M. Menten, Åke Hjalmarson, M. Hajigholi, Carina M. Persson, D. C. Lis, Maryvonne Gerin, José Cernicharo, and Holger S. P. Müller

Subjects
Physics, FOS: Physical sciences, chemistry.chemical_element, Rotational transition, Astronomy and Astrophysics, Astrophysics, Nitrogen, Astrophysics - Astrophysics of Galaxies, Space observatory, Ion, chemistry, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Ionization, Theoretical Chemistry, Ground state, Hyperfine structure, GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries)
Abstract

The understanding of interstellar nitrogen chemistry has improved significantly with recent results from the Herschel Space Observatory. To set even better constraints, we report here on deep searches for the NH+ ground state rotational transition J=1.5-0.5 of the ^2Pi_1/2 lower spin ladder, with fine-structure transitions at 1013 and 1019 GHz, and the para-NH2- 1_1,1-0_0,0 rotational transition at 934 GHz towards Sgr B2(M) and G10.6-0.4 using Herschel-HIFI. No clear detections of NH+ are made and the derived upper limits are, 14 pages, 19 figures, accepted for publication in Astronomy & Astrophysics 21 May, 2014

Published
2014

17. On the ubiquity of molecular anions in the dense interstellar medium

Author

A. O. H. Olofsson, Martin A. Cordiner, J. V. Buckle, Steven B. Charnley, and Eva Wirström

Subjects
Physics, chemistry.chemical_classification, Number density, Molecular cloud, Analytical chemistry, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, Standard deviation, Ion, Interstellar medium, Hydrocarbon, chemistry, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Radiative transfer, Density ratio
Abstract

Results are presented from a survey for molecular anions in seven nearby Galactic star-forming cores and molecular clouds. The hydrocarbon anion C6H- is detected in all seven target sources, including four sources where no anions have been previously detected: L1172, L1389, L1495B and TMC-1C. The C6H-/C6H column density ratio is greater than about 1.0% in every source, with a mean value of 3.0% (and standard deviation 0.92%). Combined with previous detections, our results show that anions are ubiquitous in dense clouds wherever C6H is present. The C6H-/C6H ratio is found to show a positive correlation with molecular hydrogen number density, and with the apparent age of the cloud. We also report the first detection of C4H- in TMC-1 (at 4.8-sigma confidence), and derive an anion-to-neutral ratio C4H-/C4H = (1.2 +- 0.4) x 10^-5 (= 0.0012 +- 0.0004%). Such a low value compared with C6H- highlights the need for a revised radiative electron attachment rate for C4H. Chemical model calculations show that the observed C4H- could be produced as a result of reactions of oxygen atoms with C5H- and C6H-.

Published
2013
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18. Multi-line detection of O_2 toward ρ Ophiuchi A

Author

Laurent Pagani, G. Olofsson, Charlotte Vastel, Gary J. Melnick, Paola Caselli, Paul F. Goldsmith, Emmanuel Caux, S. Bruderer, R. L. Snell, A. O. H. Olofsson, Åke Hjalmarson, E. Roueff, D. J. Hollenbach, J. R. Goicoechea, Pierre Encrenaz, Aa. Sandqvist, Per Bjerkeli, S. Viti, T. A. Bell, J. Le Bourlot, Per Bergman, Bengt Larsson, E. Falgarone, F. F. S. van der Tak, René Liseau, John H. Black, Di Li, Kay Justtanont, F. Le Petit, E. F. van Dishoeck, D. C. Lis, M. De Luca, Z. Nagy, Arnold O. Benz, Michael J. Kaufman, Jo-Hsin Chen, E. A. Bergin, Maryvonne Gerin, Umut A. Yildiz, foreign laboratories (FL), CERN [Genève], Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Onsala Space Observatory (OSO), Chalmers University of Technology [Göteborg], Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Department of Astronomy [Ann Arbor], University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Indiana University Cyclotron Facility (IUCF), Indiana University [Bloomington], Indiana University System-Indiana University System, Max-Planck-Institut für Extraterrestrische Physik (MPE), Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, National Taiwan University, Onsala Space Observatory, Iowa State University (ISU), SRON Netherlands Institute for Space Research (SRON), Stockholm University, Leiden Observatory [Leiden], Universiteit Leiden [Leiden], Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Astronomy, École normale supérieure - Paris (ENS-PSL), 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 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), and Universiteit Leiden

Subjects
Aperture, DARK-CLOUD, Astrophysics, MAIN CLOUD, PHOTODISSOCIATION REGIONS, 010402 general chemistry, OPH CLOUD, 7. Clean energy, 01 natural sciences, ISM: clouds, Spectral line, ISM: abundances, law.invention, Telescope, Far infrared, law, 0103 physical sciences, 010303 astronomy & astrophysics, ISM: individual objects: rho Oph A SM1, ComputingMilieux_MISCELLANEOUS, Line (formation), Physics, [PHYS]Physics [physics], DUST GRAINS, stars: formation, Molecular cloud, Astronomy and Astrophysics, ISM: molecules, 0104 chemical sciences, ISM: lines and bands, INTERSTELLAR HYDROGEN-PEROXIDE, C-I EMISSION, Interstellar medium, ODIN SATELLITE, SUBMILLIMETER OBSERVATIONS, 13. Climate action, Space and Planetary Science, MOLECULAR CLOUDS, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Water vapor
Abstract

Context. Models of pure gas-phase chemistry in well-shielded regions of molecular clouds predict relatively high levels of molecular oxygen, O-2, and water, H2O. These high abundances imply high cooling rates, leading to relatively short timescales for the evolution of gravitationally unstable dense cores, forming stars and planets. Contrary to expectations, the dedicated space missions SWAS and Odin typically found only very small amounts of water vapour and essentially no O-2 in the dense star-forming interstellar medium.Aims. Only toward rho OphA did Odin detect a very weak line of O-2 at 119 GHz in a beam of size 10 arcmin. The line emission of related molecules changes on angular scales of the order of some tens of arcseconds, requiring a larger telescope aperture such as that of the Herschel Space Observatory to resolve the O-2 emission and pinpoint its origin.Methods. We use the Heterodyne Instrument for the Far Infrared (HIFI) aboard Herschel to obtain high resolution O-2 spectra toward selected positions in the rho Oph A core. These data are analysed using standard techniques for O2 excitation and compared to recent PDR-like chemical cloud models.Results. The N-J = 3(3)-1(2) line at 487.2 GHz is clearly detected toward all three observed positions in the rho Oph A core. In addition, an oversampled map of the 5(4)-3(4) transition at 773.8 GHz reveals the detection of the line in only half of the observed area. On the basis of their ratios, the temperature of the O-2 emitting gas appears to vary quite substantially, with warm gas (greater than or similar to 50 K) being adjacent to a much colder region, of temperatures lower than 30 K.Conclusions. The exploited models predict that the O-2 column densities are sensitive to the prevailing dust temperatures, but rather insensitive to the temperatures of the gas. In agreement with these models, the observationally determined O-2 column densities do not seem to depend strongly on the derived gas temperatures, but fall into the range N(O-2) = 3 to greater than or similar to 6 x 10(15) cm(-2). Beam-averaged O-2 abundances are about 5 x 10(-8) relative to H-2. Combining the HIFI data with earlier Odin observations yields a source size at 119 GHz in the range of 4 to 5 arcmin, encompassing the entire rho Oph A core. We speculate that one of the reasons for the generally very low detection rate of O-2 is the short period of time during which O-2 molecules are reasonably abundant in molecular clouds.

Published
2012
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19. Nitrogen hydrides in interstellar gas II. Analysis of Herschel/HIFI observations towards W49N and G10.6-0.4 (W31C)

Author

John H. Black, John C. Pearson, Shanshan Yu, B. Godard, M. De Luca, Audrey Coutens, Maryvonne Gerin, Holger S. P. Müller, Bhaswati Mookerjea, Carina M. Persson, Javier R. Goicoechea, George E. Hassel, E. Herbst, Pierre Hily-Blant, A. O. H. Olofsson, Tom Bell, and Karl M. Menten

Subjects
Physics, Range (particle radiation), Absorption spectroscopy, Hydrogen molecule, Analytical chemistry, chemistry.chemical_element, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Nitrogen, Astrophysics - Astrophysics of Galaxies, Spectral line, Ammonia, chemistry.chemical_compound, chemistry, 13. Climate action, Space and Planetary Science, Abundance (ecology), Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, 010306 general physics, Absorption (electromagnetic radiation), 010303 astronomy & astrophysics
Abstract

We have used the Herschel-HIFI instrument to observe interstellar nitrogen hydrides along the sight-lines towards W49N and G10.6-0.4 in order to elucidate the production pathways leading to nitrogen-bearing species in diffuse gas. All detections show absorption by foreground material over a wide range of velocities, as well as absorption associated directly with the hot-core source itself. As in the previously published observations towards G10.6-0.4, the NH, NH2 and NH3 spectra towards W49N show strikingly similar and non-saturated absorption features. We decompose the absorption of the foreground material towards W49N into different velocity components in order to investigate whether the relative abundances vary among the velocity components, and, in addition, we re-analyse the absorption lines towards G10.6-0.4 in the same manner. Abundances, with respect to molecular hydrogen, in each velocity component are estimated using CH. The analysis points to a co-existence of the nitrogen hydrides in diffuse or translucent interstellar gas with a high molecular fraction. Towards both sources, we find that NH is always at least as abundant as both o-NH2 and o-NH3, in sharp contrast to previous results for dark clouds. We find relatively constant N(NH)/N(o-NH3) and N(o-NH2)/N(o-NH3) ratios with mean values of 3.2 and 1.9 towards W49N, and 5.4 and 2.2 towards G10.6-0.4, respectively. The mean abundance of o-NH3 is ~2x10^-9 towards both sources. The nitrogen hydrides also show linear correlations with CN and HNC towards both sources, and looser correlations with CH. The upper limits on the NH+ abundance indicate column densities < 2 - 14 % of N(NH). Surprisingly low values of the ammonia ortho-to-para ratio are found in both sources, ~0.5 - 0.7 +- 0.1. This result cannot be explained by current models as we had expected to find a value of unity or higher., 35 pages, 74 figures

Published
2012
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20. Herschel observations of the Herbig-Haro objects HH52-54

Author

Kay Justtanont, G. J. Herczeg, A. O. H. Olofsson, C. McCoey, René Liseau, Per Bergman, Mario Tafalla, Odysseas Dionatos, Brunella Nisini, M. Benedettini, Per Bjerkeli, Teresa Giannini, Bengt Larsson, and Michael Olberg

Subjects
Shock wave, Physics, formation [stars], jets and outflows [ISM], FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, Spectral line, Shock (mechanics), Herbig-Haro objects, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Radiative transfer, Outflow, Herbig–Haro object, Spectral resolution, winds, outflows [stars], molecules [ISM], Astrophysics::Galaxy Astrophysics, Line (formation)
Abstract

We are aiming at the observational estimation of the relative contribution to the cooling by CO and H2O, as this provides decisive information for the understanding of the oxygen chemistry behind interstellar shock waves. Methods. The high sensitivity of HIFI, in combination with its high spectral resolution capability, allows us to trace the H2O outflow wings at unprecedented signal-to-noise. From the observation of spectrally resolved H2O and CO lines in the HH52-54 system, both from space and from ground, we arrive at the spatial and velocity distribution of the molecular outflow gas. Solving the statistical equilibrium and non-LTE radiative transfer equations provides us with estimates of the physical parameters of this gas, including the cooling rate ratios of the species. The radiative transfer is based on an ALI code, where we use the fact that variable shock strengths, distributed along the front, are naturally implied by a curved surface. Based on observations of CO and H2O spectral lines, we conclude that the emission is confined to the HH54 region. The quantitative analysis of our observations favours a ratio of the CO-to-H2O-cooling-rate >> 1. From the best-fit model to the CO emission, we arrive at an H2O abundance close to 1e-5. The line profiles exhibit two components, one of which is triangular and another, which is a superposed, additional feature. This additional feature likely originates from a region smaller than the beam where the ortho-water abundance is smaller than in the quiescent gas. Comparison with recent shock models indicate that a planar shock can not easily explain the observed line strengths and triangular line profiles.We conclude that the geometry can play an important role. Although abundances support a scenario where J-type shocks are present, higher cooling rate ratios than predicted by these type of shocks are derived., Accepted for publication in A&A

Published
2011
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21. Ground-state ammonia and water in absorption towards Sgr B2

Author

John H. Black, Pierre Encrenaz, Michael Olberg, A. O. H. Olofsson, Eva Wirström, Åke Hjalmarson, Urban Frisk, Aa. Sandqvist, Edith Falgarone, B. Larsson, Per Bergman, Onsala Space Observatory, Chalmers University of Technology (OSO), Stockholm Observatory, AlbaNova University Center, Galaxies, Etoiles, Physique, Instrumentation (GEPI), 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), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Instrumentation et télédétection, 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), 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)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Dynamique des milieux interstellaires et plasmas stellaires, and Swedish Space Corporation (SSC)

Subjects
Physics, Molecular cloud, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Space and Planetary Science, Nucleosynthesis, Astrophysics of Galaxies (astro-ph.GA), Isotopologue, Disc, Absorption (electromagnetic radiation), Ground state, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Line (formation)
Abstract

We have used the Odin submillimetre-wave satellite telescope to observe the ground state transitions of ortho-ammonia and ortho-water, including their 15N, 18O, and 17O isotopologues, towards Sgr B2. The extensive simultaneous velocity coverage of the observations, >500 km/s, ensures that we can probe the conditions of both the warm, dense gas of the molecular cloud Sgr B2 near the Galactic centre, and the more diffuse gas in the Galactic disk clouds along the line-of-sight. We present ground-state NH3 absorption in seven distinct velocity features along the line-of-sight towards Sgr B2. We find a nearly linear correlation between the column densities of NH3 and CS, and a square-root relation to N2H+. The ammonia abundance in these diffuse Galactic disk clouds is estimated to be about (0.5-1)e-8, similar to that observed for diffuse clouds in the outer Galaxy. On the basis of the detection of H218O absorption in the 3 kpc arm, and the absence of such a feature in the H217O spectrum, we conclude that the water abundance is around 1e-7, compared to ~1e-8 for NH3. The Sgr B2 molecular cloud itself is seen in absorption in NH3, 15NH3, H2O, H218O, and H217O, with emission superimposed on the absorption in the main isotopologues. The non-LTE excitation of NH3 in the environment of Sgr B2 can be explained without invoking an unusually hot (500 K) molecular layer. A hot layer is similarly not required to explain the line profiles of the 1_{1,0}-1_{0,1} transition from H2O and its isotopologues. The relatively weak 15NH3 absorption in the Sgr B2 molecular cloud indicates a high [14N/15N] isotopic ratio >600. The abundance ratio of H218O and H217O is found to be relatively low, 2.5--3. These results together indicate that the dominant nucleosynthesis process in the Galactic centre is CNO hydrogen burning., 10 pages, 5 figures

Published
2010
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22. A spectral line survey of Orion KL in the bands 486-492 and 541-577 GHz with the Odin satellite I. The observational data

Author

Alain Lecacheux, Michael Olberg, Sun Kwok, Aa. Sandqvist, Peter F. Bernath, Per Bergman, A. Nummelin, Carina M. Persson, Nico Koning, Urban Frisk, Tatsuhiko I. Hasegawa, A. O. H. Olofsson, B. Larsson, Åke Hjalmarson, Eva Wirström, Wolf D. Geppert, John H. Black, Onsala Space Observatory, Chalmers University of Technology (OSO), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), University of Calgary, Department of Chemistry, University of Arizona, Swedish Space Corporation (SSC), Molecular Physics Division, Department of Physics, Stockholm Observatory, AlbaNova University Center, 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), Physique des plasmas, 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 Computer science and engineering

Subjects
Physics, ISM: individual: objects: Orion KL, Molecular cloud, Aeronomy, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Spectral line, ISM: molecules, law.invention, ISM: lines and bands, Telescope, Wavelength, surveys, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, law, Isotopologue, submillimeter, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Noise (radio), Solar and Stellar Astrophysics (astro-ph.SR), line: identification, Line (formation)
Abstract

Spectral line surveys are useful since they allow identification of new molecules and new lines in uniformly calibrated data sets. Nonetheless, large portions of the sub-millimetre spectral regime remain unexplored due to severe absorptions by H2O and O2 in the terrestrial atmosphere. The purpose of the measurements presented here is to cover wavelength regions at and around 0.55 mm -- regions largely unobservable from the ground. Using the Odin astronomy/aeronomy satellite, we performed the first spectral survey of the Orion KL molecular cloud core in the bands 486--492 and 541--576 GHz with rather uniform sensitivity (22--25 mK baseline noise). Odin's 1.1 m size telescope, equipped with four cryo-cooled tuneable mixers connected to broad band spectrometers, was used in a satellite position-switching mode. Two mixers simultaneously observed different 1.1 GHz bands using frequency steps of 0.5 GHz (25 hours each). An on-source integration time of 20 hours was achieved for most bands. The entire campaign consumed ~1100 orbits, each containing one hour of serviceable astro-observation. We identified 280 spectral lines from 38 known interstellar molecules (including isotopologues) having intensities in the range 80 to 0.05 K. An additional 64 weak lines remain unidentified. Apart from the ground state rotational 1(1,0)--1(0,1) transitions of ortho-H2O, H218O and H217O, the high energy 6(2,4)--7(1,7) line of para-H2O and the HDO(2,0,2--1,1,1) line have been observed, as well as the 1,0--0,1 lines from NH3 and its rare isotopologue 15NH3. We suggest assignments for some unidentified features, notably the new interstellar molecules ND and SH-. Severe blends have been detected in the line wings of the H218O, H217O and 13CO lines changing the true linewidths of the outflow emission., 21 pages, 10 figures, 7 tables, accepeted for publication in Astronomy and Astrophysics 30 August 2007

Published
2009
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23. Odin observations of water in molecular outflows and shocks

Author

Per Bjerkeli, Aa. Sandqvist, Edith Falgarone, Göran Olofsson, Åke Hjalmarson, Alain Klotz, Urban Frisk, I. Ristorcelli, René Liseau, Michael Olberg, A. O. H. Olofsson, Bengt Larsson, Onsala Space Observatory, Chalmers University of Technology (OSO), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Swedish Space Corporation (SSC), Centre d'étude spatiale des rayonnements (CESR), 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), Stockholm Observatory, AlbaNova University Center, Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)

Subjects
ROTATIONAL-EXCITATION, WAVE-ASTRONOMY-SATELLITE, FOS: Physical sciences, SUPERNOVA REMNANT IC-443, Astrophysics, stars: pre-main sequence, Volume density, STAR-FORMATION, Abundance (ecology), Range (statistics), SERPENS CLOUD CORE, Solar and Stellar Astrophysics (astro-ph.SR), Line (formation), ISM: supernova remnants, NGC 6334 I, Physics, Shock (fluid dynamics), SUBMILLIMETER CONTINUUM, Astronomy and Astrophysics, TW-HYDRAE, ISM: molecules, COLLISIONAL EXCITATION, Supernova, ISM: jets and outflows, BIPOLAR OUTFLOW, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Outflow, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Loss rate
Abstract

Aims. We investigate the ortho-water abundance in outflows and shocks in order to improve our knowledge of shock chemistry and of the physics behind molecular outflows. Methods. We have used the Odin space observatory to observe the H2O(110-101) line. We obtain strip maps and single pointings of 13 outflows and two supernova remnants where we report detections for eight sources. We have used RADEX to compute the beam averaged abundances of o-H2O relative to H2. In the case of non-detection, we derive upper limits on the abundance. Results. Observations of CO emission from the literature show that the volume density of H2 can vary to a large extent, a parameter that puts severe uncertainties on the derived abundances. Our analysis shows a wide range of abundances reflecting the degree to which shock chemistry is affecting the formation and destruction of water. We also compare our results with recent results from the SWAS team. Conclusions. Elevated abundances of ortho-water are found in several sources. The abundance reaches values as high as what would be expected from a theoretical C-type shock where all oxygen, not in the form of CO, is converted to water. However, the high abundances we derive could also be due to the low densities (derived from CO observations) that we assume. The water emission may in reality stem from high density regions much smaller than the Odin beam. We do not find any relationship between the abundance and the mass loss rate. On the other hand, there is a relation between the derived water abundance and the observed maximum outflow velocity., 19 pages, 20 figures, 4 tables

Published
2009
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24. A spectral line survey of Orion KL in the bands 486-492 and 541-577 GHz with the Odin satellite II. Data analysis

Author

Peter F. Bernath, Eva Wirström, A. O. H. Olofsson, Aa. Sandqvist, Alain Lecacheux, Urban Frisk, Carina M. Persson, B. Larsson, Sun Kwok, Michael Olberg, Nico Koning, A. Nummelin, Wolf D. Geppert, John H. Black, Per Bergman, Tatsuhiko I. Hasegawa, Åke Hjalmarson, Onsala Space Observatory, Chalmers University of Technology (OSO), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), University of Calgary, Department of Chemistry, University of Waterloo, Swedish Space Corporation (SSC), Molecular Physics Division, Department of Physics, Stockholm Observatory, AlbaNova University Center, 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), Physique des plasmas, 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 Computer science and engineering

Subjects
Physics, Opacity, Rotational transition, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Spectral line, Atmosphere, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Isotopologue, Satellite, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Absorption (electromagnetic radiation), Ground state, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

We investigate the physical and chemical conditions in a typical star forming region, including an unbiased search for new molecules in a spectral region previously unobserved. Due to its proximity, the Orion KL region offers a unique laboratory of molecular astrophysics in a chemically rich, massive star forming region. Several ground-based spectral line surveys have been made, but due to the absorption by water and oxygen, the terrestrial atmosphere is completely opaque at frequencies around 487 and 557 GHz. To cover these frequencies we used the Odin satellite to perform a spectral line survey in the frequency ranges 486-492 GHz and 541-577 GHz, filling the gaps between previous spectral scans. Odin's high main beam efficiency and observations performed outside the atmosphere make our intensity scale very well determined. We observed 280 spectral lines from 38 molecules including isotopologues, and, in addition, 64 unidentified lines. The beam-averaged emission is dominated by CO, H2O, SO2, SO, 13CO and CH3OH. Species with the largest number of lines are CH3OH, (CH33)2O, SO2, 13CH3OH, CH3CN and NO. Six water lines are detected including the ground state rotational transition o-H2O, its isotopologues o-H218O and o-H217O, the Hot Core tracing p-H2O transition 6(2,4)-7(1,7), and the 2(0, 2)-1(1,1) transition of HDO. Other lines of special interest are the 1_0-0_0 transition of NH3 and its isotopologue 15NH3. Isotopologue abundance ratios of D/H, 12C/13C, 32S/34S, 34S/33S, and 18O/17O are estimated. The temperatures, column densities and abundances in the various subregions are estimated, and we find very high gas-phase abundances of H2O, NH3, SO2, SO, NO, and CH3OH. A comparison with the ice inventory of ISO sheds new light on the origin of the abundant gas-phase molecules., Comment: 51 pages, 47 figures, 35 tables, accepted for publication in Astronomy and Astrophysics 17 September 2007

Published
2009
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25. Molecular oxygen in the rho Ophiuchi cloud

Author

Nicholas F. H Tothill, Alain Klotz, René Liseau, P. A. Feldman, Christine D. Wilson, Maryvonne Gerin, N. Biver, Steve Torchinsky, G. F. Gahm, Cathy Horellou, H. G. Floren, George F. Mitchell, Alain Lecacheux, Laurent Pagani, Urban Frisk, G. Olofsson, John H. Black, Georg Witt, V. Buat, E. Kyroelae, Gérard Mégie, G. Serra, Hans Rickman, Roy Booth, Tatsuhiko I. Hasegawa, L. Nordh, Aa. Hjalmarson, Peter F. Bernath, Anders Winnberg, Per Bergman, L.-Aa. Nyman, L. E. B. Johansson, Gustaf Rydbeck, A. O. H. Olofsson, P. J. Encrenaz, Kevin Volk, G. Persson, E. Falgarone, M. Fich, Michael Olberg, I. Ristorcelli, S. Lundin, Aa. Sandqvist, Fredrik von Schéele, Magnus Dahlgren, Rene Plume, Donal P. Murtagh, M. Hagstroem, Charles L. Curry, Bengt Larsson, Hans Olofsson, Sun Kwok, Jacques Crovisier, Tommy Wiklind, Kay Justtanont, E. J. Llewellyn, Jorma Harju, Mathias Fredrixon, T. Liljestroem, Stockholm Observatory, AlbaNova University Center, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Onsala Space Observatory, Chalmers University of Technology (OSO), Department of Physics, University of Waterloo, 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), Physique des plasmas, 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, Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire d'Astronomie Spatiale (LAS), Centre National de la Recherche Scientifique (CNRS), National Research Council of Canada (NRC), Swedish Space Corporation (SSC), Jakokoski Observatory, University of Helsinki, University of Calgary, Centre d'étude spatiale des rayonnements (CESR), 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), Finnish Meteorological Institute (FMI), Metsähovi Radio Observatory, University of Saskatchewan [Saskatoon] (U of S), Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Department of Astronomy and Physics, Saint Mary's University, Global Environmental Measurements Group, Swedish National Space Board (SNSB), APEX team, ESO, Santiago, Uppsala Astronomical Observatory, Canadian Space Agency (CSA), Department of Physics and Astronomy, McMaster University, and Department of Meteorology, Stockholm University

Subjects
Physics, Molecular cloud, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Spectral line, Interstellar medium, Chemical species, Space and Planetary Science, Satellite, Ground state, Spectroscopy, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Line (formation)
Abstract

Molecular oxygen, O2 has been expected historically to be an abundant component of the chemical species in molecular clouds and, as such, an important coolant of the dense interstellar medium. However, a number of attempts from both ground and from space have failed to detect O2 emission. The work described here uses heterodyne spectroscopy from space to search for molecular oxygen in the interstellar medium. The Odin satellite carries a 1.1 m sub-millimeter dish and a dedicated 119 GHz receiver for the ground state line of O2. Starting in 2002, the star forming molecular cloud core rho Oph A was observed with Odin for 34 days during several observing runs. We detect a spectral line at v(LSR) = 3.5 km/s with dv(FWHM) = 1.5 km/s, parameters which are also common to other species associated with rho Ohp A. This feature is identified as the O2 (N_J = 1_1 - 1_0) transition at 118 750.343 MHz. The abundance of molecular oxygen, relative to H2,, is 5E-8 averaged over the Odin beam. This abundance is consistently lower than previously reported upper limits., Comment: 10 pages, 11 figures, accepted for publication in A&A

Published
2007
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26. A new 3 mm band receiver for the Onsala 20 m antenna

Author

Jonas Flygare, John Conway, Alexey Pavolotsky, M. Whale, A. O. H. Olofsson, Per Bergman, Igor Lapkin, Mathias Fredrixon, Mikael S. Lerner, Victor Belitsky, Bhushan Billade, Magnus Strandberg, Leif Helldner, Erik Sundin, Hans Olofsson, Sven-Erik Ferm, Miroslav Pantaleev, and Lars Pettersson

Subjects
Physics, Sideband, business.industry, Frequency band, Local oscillator, Astronomy and Astrophysics, Astrophysics, Optical switch, Orthomode transducer, Phase-locked loop, Optics, Intermediate frequency, Space and Planetary Science, business, Gunn diode
Abstract

A new receiver for the Onsala 20 m antenna with the possibility of being equipped with 3 mm and 4 mm bands has been built and the 3 mm channel has been commissioned during the Spring 2014. For single-dish operation, the receiver uses an innovative on-source/off-source optical switch. In combination with additional optical components and within the same optical layout, the switch provides two calibration loads (for the 3 mm and 4 mm channels), sideband rejection measurement, and tuning possibilities. The optical layout of the receiver employs all cold (4 K) offset elliptical mirrors for both channels, whereas the on-off switch employs flat mirrors only. The 3 mm channel employs a sideband separation (2SB) dual polarization receiver with orthomode transducer (OMT), 4-8 GHz intermediate frequency (IF), x? 2pol x? upper and lower sidebands (USB? +? LSB). The cryostat has four optical windows made of high density polyethylene (HDPE) with anti-reflection corrugations, two for the signal and two for each frequency band cold load. The cryostat uses a two-stage cryocooler produced by Sumitomo HI? RDK? 408D2 with anti-vibration suspension of the cold-head to minimize impact of the vibrations on the receiver stability. The local oscillator (LO) system is based on a Gunn oscillator with aphase lock loop (PLL) and four mechanical tuners for broadband operation, providing independently tunable LO power for each polarization. This paper provides a technical description of the receiver and its technology and could be useful for instrumentation engineers and observers using the Onsala 20 m telescope.

Published
2015
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27. Searching for O$_2$ in the SMC:Constraints on Oxygen Chemistry at Low Metallicities

Author

Michael Olberg, Christine D. Wilson, Urban Frisk, Aa. Sandqvist, Roy Booth, Åke Hjalmarson, A. O. H. Olofsson, and Laurent Pagani

Subjects
Physics, Molecular cloud, Astrophysics (astro-ph), chemistry.chemical_element, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Oxygen, chemistry, Space and Planetary Science, Abundance (ecology), Limit (mathematics), Small Magellanic Cloud, Line (formation)
Abstract

We present a 39 h integration with the Odin satellite on the ground-state 118.75 GHz line of O2 towards the region of strongest molecular emission in the Small Magellanic Cloud. Our 3sigma upper limit to the O2 integrated intensity of, 4 pages, accepted to A&A Letters

Published
2005

28. Odin observations of H2O in the Galactic Centre

Author

E. M. Gregersen, George F. Mitchell, Pierre Encrenaz, P. A. Feldman, Alain Lecacheux, Kalevi Mattila, A. O. H. Olofsson, M. Olberg, Nicholas F. H Tothill, Charles L. Curry, Roy Booth, Urban Frisk, Sun Kwok, B. Larsson, Per Bergman, Kevin Volk, A. Winnberg, M. Lindqvist, Christine D. Wilson, I. Ristorcelli, G. Olofsson, Åke Hjalmarson, M. Fich, R. Plume, Maryvonne Gerin, Fredrik von Schéele, T. Liljeström, Edith Falgarone, John H. Black, Tatsuhiko I. Hasegawa, V. Buat, L. Nordh, René Liseau, H. G. Floren, Jorma Harju, G. Serra, Aa. Sandqvist, L. E. B. Johansson, Laurent Pagani, 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), Physique des plasmas, 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, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 de Cergy Pontoise (UCP), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Spiral galaxy, Absorption spectroscopy, 010308 nuclear & particles physics, Molecular cloud, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Space and Planetary Science, [SDU]Sciences of the Universe [physics], 0103 physical sciences, Emission spectrum, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics
Abstract

The Odin satellite has been used to detect emission and absorption in the 557-GHz H2O line in the Galactic Centre towards the Sgr A* Circumnuclear Disk (CND), and the Sgr A +20 km/s and +50 km/s molecular clouds. Strong broad H2O emission lines have been detected in all three objects. Narrow H2O absorption lines are present at all three positions and originate along the lines of sight in the 3-kpc Spiral Arm, the -30 km/s Spiral Arm and the Local Sgr Spiral Arm. Broad H2O absorption lines near -130 km/s are also observed, originating in the Expanding Molecular Ring. A new molecular feature (the ``High Positive Velocity Gas'' - HPVG) has been identified in the positive velocity range of ~ +120 to +220 km/s, seen definitely in absorption against the stronger dust continuum emission from the +20 km/s and +50 km/s clouds and possibly in emission towards the position of Sgr A* CND. The 548-GHz H2_18O isotope line towards the CND is not detected at the 0.02 K (rms) level., 5 pages, 3 figures, accepted by A&A, special Odin Letters issue

Published
2003
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29. Submillimeter emission from water in the W3 region

Author

Urban Frisk, A. M. Mason, Jorma Harju, Christine D. Wilson, M. Fich, A. O. H. Olofsson, Åke Hjalmarson, L. Nordh, Per Bergman, René Liseau, Kevin Volk, Aa. Sandqvist, H. G. Floren, Pierre Encrenaz, V. Buat, Rene Plume, Charles L. Curry, Laurent Pagani, E. Falgarone, L. Ristorcelli, Bengt Larsson, Tetsuo Hasegawa, K. Mattila, F. von Schéele, N. Boudet, Sun Kwok, G. Olofsson, G. Serra, Nicholas F. H Tothill, Mika Juvela, P. A. Feldman, Maryvonne Gerin, E. M. Gregersen, Alain Lecacheux, George F. Mitchell, Michael Olberg, Roy Booth, T. Liljeström, 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), Physique des plasmas, 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, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 de Cergy Pontoise (UCP), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Relative strength, Astrophysics, Absorption (electromagnetic radiation), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Spectral line, Line (formation)
Abstract

We have mapped the submillimeter emission from the 1(10)-1(01) transition of ortho-water in the W3 star-forming region. A 5'x5' map of the W3 IRS4 and W3 IRS5 region reveals strong water lines at half the positions in the map. The relative strength of the Odin lines compared to previous observations by SWAS suggests that we are seeing water emission from an extended region. Across much of the map the lines are double-peaked, with an absorption feature at -39 km/s; however, some positions in the map show a single strong line at -43 km/s. We interpret the double-peaked lines as arising from optically thick, self-absorbed water emission near the W3 IRS5, while the narrower blue-shifted lines originate in emission near W3 IRS4. In this model, the unusual appearance of the spectral lines across the map results from a coincidental agreement in velocity between the emission near W3 IRS4 and the blue peak of the more complex lines near W3 IRS5. The strength of the water lines near W3 IRS4 suggests we may be seeing water emission enhanced in a photon-dominated region., Accepted to A&A Letters as part of the special Odin issue; 4 pages

Published
2003
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30. Odin water mapping in the Orion KL region

Author

John H. Black, G. Serra, Maryvonne Gerin, Michael Olberg, I. Ristorcelli, Bengt Larsson, E. M. Gregersen, Tatsuhiko I. Hasegawa, Aa. Sandqvist, Alain Lecacheux, Edith Falgarone, Pierre Encrenaz, G. Olofsson, Charles L. Curry, M. Fich, Hans Olofsson, H. L. Nordh, Jorma Harju, T. Liljeström, Nicholas F. H Tothill, Urban Frisk, F. von Schéele, L. E. B. Johansson, Åke Hjalmarson, René Liseau, George F. Mitchell, H. G. Floren, Kalevi Mattila, Roy Booth, P. A. Feldman, Sun Kwok, Per Bergman, Christine D. Wilson, Rene Plume, V. Buat, Gustaf Rydbeck, A. O. H. Olofsson, Kevin Volk, Laurent Pagani, 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), Physique des plasmas, 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, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 de Cergy Pontoise (UCP), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, 010308 nuclear & particles physics, media_common.quotation_subject, Astronomy, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, 7. Clean energy, Asymmetry, Beam size, [SDU]Sciences of the Universe [physics], Space and Planetary Science, 0103 physical sciences, Outflow, Satellite, Halo, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Line (formation), media_common
Abstract

New results from water mapping observations of the Orion KL region using the submm/mm wave satellite Odin (2.1\arcmin beam size at 557 GHz), are presented. The ortho-H2O \jkktrans{1}{1}{0}{1}{0}{1} ground state transition was observed in a 7arcminx 7arcmin rectangular grid with a spacing of 1\arcmin, while the same line of H218O was measured in two positions, Orion KL itself and 2\arcmin south of Orion KL. In the main water species, the KL molecular outflow is largely resolved from the ambient cloud and it is found to have an extension of 60\arcsec-110\arcsec. The H2O outflow profile exhibits a rather striking absorption-like asymmetry at the line centre. Self-absorption in the near (or ``blue'') part of the outflow (and possibly in foreground quiescent halo gas) is tentatively suggested to play a role here. We argue that the dominant part of the KL H218O outflow emission emanates from the compact (size ~ 15\arcsec) low-velocity flow and here estimate an H2O abundance of circa 10-5 compared to all H2 in the flow - an order of magnitude below earlier estimates of the H2O abundance in the shocked gas of the high-velocity flow. The narrow ambient cloud lines show weak velocity trends, both in the N-S and E-W directions. H218O is detected for the first time in the southern position at a level of ~ 0.15 K and we here estimate an H2O abundance of (1-8) x 10-8. Odin is a Swedish-led satellite project funded jointly by the Swedish National Space Board (SNSB), the Canadian Space Agency (CSA), the National Technology Agency of Finland (Tekes), and the Centre National d'Etudes Spatiales (CNES, France). The Swedish Space Corporation (SSC) was the industrial prime contractor and is also responsible for the satellite operation.

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31. Highlights from the first year of Odin observations

Author

P. A. Feldman, René Liseau, Mathias Fredrixon, Edward J. Llewellyn, George F. Mitchell, L.-Å. Nyman, Hans Olofsson, Cathy Horellou, F. von Schéele, Gustaf Rydbeck, A. O. H. Olofsson, H. G. Floren, Tommy Wiklind, Michael Olberg, Christine D. Wilson, I. Ristorcelli, G. Persson, Roy Booth, Erkki Kyrölä, G. Olofsson, Edith Falgarone, Alain Lecacheux, John H. Black, G. Serra, Michael Lindqvist, Pierre Encrenaz, Nicolas Biver, T. Liljeström, Jorma Harju, Aa. Sandqvist, Sun Kwok, Georg Witt, Anders Winnberg, Rene Plume, Donal P. Murtagh, Magnus Dahlgren, Maryvonne Gerin, Tatsuhiko I. Hasegawa, Peter F. Bernath, L. E. B. Johansson, Urban Frisk, Kalevi Mattila, E. M. Gregersen, Per Bergman, M. Fich, Nicholas F. H Tothill, H. L. Nordh, Åke Hjalmarson, Bengt Larsson, Jacques Crovisier, Laurent Pagani, Steve Torchinsky, G. Mégie, Hans Rickman, V. Buat, Magne Hagström, Charles L. Curry, Kevin Volk, 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), Physique des plasmas, 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, Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 de Cergy Pontoise (UCP), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Mission control center, Chemical models, Comet, Astronomy, Astronomy and Astrophysics, Astrophysics, 7. Clean energy, 01 natural sciences, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, 0103 physical sciences, Satellite, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010306 general physics, 010303 astronomy & astrophysics, Millimetre wave
Abstract

Key Odin operational and instrumental features and highlights from our sub-millimetre and millimetre wave observations of H2O, H218O, NH3, 15NH3 and O2 are presented, with some insights into accompanying Odin Letters in this AA H2O observations of Galactic Centre sources, of shock enhanced H2O towards the SNR IC443, and of the candidate infall source IRAS 16293-2422; H218O detections in Orion KL and in comet Ikeya-Zhang; sub-mm detections of NH3 in Orion KL (outflow, ambient cloud and bar) and ρ Oph, and very recently, of 15NH3 in~Orion KL. Simultaneous sensitive searches for the 119 GHz line of O2 have resulted in very low abundance limits, which are difficult to accomodate in chemical models. We also demonstrate, by means of a quantitative comparison of Orion KL H2O results, that the Odin and SWAS observational data sets are very consistently calibrated. Odin is a Swedish-led satellite project funded jointly by the Swedish National Space Board (SNSB), the Canadian Space Agency (CSA), the National Technology Agency of Finland (Tekes), and the Centre National d'etudes Spatiales (CNES, France). The Swedish Space Corporation (SSC) has been the prime industrial contractor, and is also responsible for the satellite operation from its Odin Mission Control Centre at SSC in Solna and its Odin Control Centre at ESRANGE near Kiruna in northern Sweden. See also the SNSB Odin web page: http://www.snsb.se/eng_odin_intro.shtml

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