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Goicoechea JR, Teyssier D, Etxaluze M, Goldsmith PF, Ossenkopf V, Gerin M, Bergin EA, Black JH, Cernicharo J, Cuadrado S, Encrenaz P, Falgarone E, Fuente A, Hacar A, Lis DC, Marcelino N, Melnick GJ, Müller HSP, Persson C, Pety J, Röllig M, Schilke P, Simon R, Snell RL, Stutzki J. VELOCITY-RESOLVED [C ii] EMISSION AND [C ii]/FIR MAPPING ALONG ORION WITH HERSCHEL.. ACTA ACUST UNITED AC 2015; 812. [PMID: 26568638 DOI: 10.1088/0004-637x/812/1/75] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We present the first ~7.5'×11.5' velocity-resolved (~0.2 km s-1) map of the [C ii] 158 μm line toward the Orion molecular cloud 1 (OMC 1) taken with the Herschel/HIFI instrument. In combination with far-infrared (FIR) photometric images and velocity-resolved maps of the H41α hydrogen recombination and CO J=2-1 lines, this data set provides an unprecedented view of the intricate small-scale kinematics of the ionized/PDR/molecular gas interfaces and of the radiative feedback from massive stars. The main contribution to the [C ii] luminosity (~85 %) is from the extended, FUV-illuminated face of the cloud (G0>500, nH>5×103 cm-3) and from dense PDRs (G≳104, nH≳105 cm-3) at the interface between OMC 1 and the H ii region surrounding the Trapezium cluster. Around ~15 % of the [C ii] emission arises from a different gas component without CO counterpart. The [C ii] excitation, PDR gas turbulence, line opacity (from [13C ii]) and role of the geometry of the illuminating stars with respect to the cloud are investigated. We construct maps of the L[C ii]/LFIR and LFIR/MGas ratios and show that L[C ii]/LFIR decreases from the extended cloud component (~10-2-10-3) to the more opaque star-forming cores (~10-3-10-4). The lowest values are reminiscent of the "[C ii] deficit" seen in local ultra-luminous IR galaxies hosting vigorous star formation. Spatial correlation analysis shows that the decreasing L[C ii]/LFIR ratio correlates better with the column density of dust through the molecular cloud than with LFIR/MGas. We conclude that the [C ii] emitting column relative to the total dust column along each line of sight is responsible for the observed L[C ii]/LFIR variations through the cloud.
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Affiliation(s)
- Javier R Goicoechea
- Instituto de Ciencia de Materiales de Madrid (CSIC). Calle Sor Juana Ines de la Cruz 3, E-28049 Cantoblanco, Madrid, Spain
| | - D Teyssier
- Herschel Science Centre, ESA/ESAC, P.O. Box 78, Villanueva de la Cañada, E-28691 Madrid, Spain
| | - M Etxaluze
- Instituto de Ciencia de Materiales de Madrid (CSIC). Calle Sor Juana Ines de la Cruz 3, E-28049 Cantoblanco, Madrid, Spain ; RAL Space, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - P F Goldsmith
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099, USA
| | - V Ossenkopf
- I. Physikalisches Institut der Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
| | - M Gerin
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, F-75014, Paris, France ; École Normale Supérieure, 24 rue Lhomond, F-75005, Paris, France
| | - E A Bergin
- Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109, USA
| | - J H Black
- Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-43992 Onsala, Sweden
| | - J Cernicharo
- Instituto de Ciencia de Materiales de Madrid (CSIC). Calle Sor Juana Ines de la Cruz 3, E-28049 Cantoblanco, Madrid, Spain
| | - S Cuadrado
- Instituto de Ciencia de Materiales de Madrid (CSIC). Calle Sor Juana Ines de la Cruz 3, E-28049 Cantoblanco, Madrid, Spain
| | - P Encrenaz
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, F-75014, Paris, France
| | - E Falgarone
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, F-75014, Paris, France ; École Normale Supérieure, 24 rue Lhomond, F-75005, Paris, France
| | - A Fuente
- Observatorio Astronómico Nacional (OAN IGN), Apdo. 112, 28803, Alcalá de Henares, Spain
| | - A Hacar
- Institute for Astrophysics, University of Vienna, Türkenschanzstrasse 17, 1180, Vienna, Austria
| | - D C Lis
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, F-75014, Paris, France
| | - N Marcelino
- INAF, Istituto di Radioastronomia, via P. Gobetti 101, 40129, Bologna, Italy
| | - G J Melnick
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 66, Cambridge, MA 02138, USA
| | - H S P Müller
- I. Physikalisches Institut der Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
| | - C Persson
- Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-43992 Onsala, Sweden
| | - J Pety
- Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, 38406 Saint-Martin d'Héeres, France
| | - M Röllig
- I. Physikalisches Institut der Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
| | - P Schilke
- I. Physikalisches Institut der Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
| | - R Simon
- I. Physikalisches Institut der Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
| | - R L Snell
- Department of Astronomy, University of Massachusetts, LGRT-B 619E, 710 North Pleasant Street, Amherst, MA 01003, USA
| | - J Stutzki
- I. Physikalisches Institut der Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
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Cernicharo J, Teyssier D, Quintana-Lacaci G, Daniel F, Agúndez M, Prieto LV, Decin L, Guélin M, Encrenaz P, García-Lario P, de Beck E, Barlow MJ, Groenewegen MAT, Neufeld D, Pearson J. Discovery of Time Variation of the Intensity of Molecular Lines in IRC+10216 in The Submillimeter and Far Infrared Domains. Astrophys J Lett 2014; 796:L21. [PMID: 26722620 PMCID: PMC4693957 DOI: 10.1088/2041-8205/796/1/l21] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report on the discovery of strong intensity variations in the high rotational lines of abundant molecular species towards the archetypical circumstellar envelope of IRC+10216. The observations have been carried out with the HIFI instrument on board Herschel and with the IRAM 30-m telescope. They cover several observing periods spreading over 3 years. The line intensity variations for molecules produced in the external layers of the envelope most probably result from time variations in the infrared pumping rates. We analyze the main implications this discovery has on the interpretation of molecular line emission in the envelopes of Mira-type stars. Radiative transfer calculations have to take into account both the time variability of infrared pumping and the possible variation of the dust and gas temperatures with stellar phase in order to reproduce the observation of molecular lines at different epochs. The effect of gas temperature variations with stellar phase could be particularly important for lines produced in the innermost regions of the envelope. Each layer of the circumstellar envelope sees the stellar light radiation with a different lag time (phase). Our results show that this effect must be included in the models. The sub-mm and FIR lines of AGB stars cannot anymore be considered as safe intensity calibrators.
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Affiliation(s)
- J Cernicharo
- Group of Molecular Astrophysics. ICMM. CSIC. C/Sor Juana Inés de La Cruz N3. E-28049, Madrid. Spain
| | - D Teyssier
- ESA. ESAC. P.O. Box 78, Villanueva de la Cañada E-28691 Madrid. Spain
| | - G Quintana-Lacaci
- Group of Molecular Astrophysics. ICMM. CSIC. C/Sor Juana Inés de La Cruz N3. E-28049, Madrid. Spain
| | - F Daniel
- Univ. Grenoble Alpes, IPAG, F-38000 Grenoble, France CNRS, IPAG, F-38000 Grenoble, France
| | - M Agúndez
- Group of Molecular Astrophysics. ICMM. CSIC. C/Sor Juana Inés de La Cruz N3. E-28049, Madrid. Spain
| | - L Velilla Prieto
- Group of Molecular Astrophysics. ICMM. CSIC. C/Sor Juana Inés de La Cruz N3. E-28049, Madrid. Spain
| | - L Decin
- Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium
| | - M Guélin
- Institut de Radioastronomie Millimétrique, 300 rue de la Piscine, F-38406, St-Martin d'Hères, France
| | - P Encrenaz
- LERMA, Observatoire de Paris, 61 Av. de l'Observatoire, F-75014 Paris, France
| | - P García-Lario
- ESA. ESAC. P.O. Box 78, Villanueva de la Cañada E-28691 Madrid. Spain
| | - E de Beck
- Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE 43992 Onsala, Sweden
| | - M J Barlow
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK
| | - M A T Groenewegen
- Koninklijke Sterrenwacht van België, Ringlaan 3, B-1180, Brussel, Belgium
| | - D Neufeld
- Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA
| | - J Pearson
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91109, USA
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Stofan ER, Elachi C, Lunine JI, Lorenz RD, Stiles B, Mitchell KL, Ostro S, Soderblom L, Wood C, Zebker H, Wall S, Janssen M, Kirk R, Lopes R, Paganelli F, Radebaugh J, Wye L, Anderson Y, Allison M, Boehmer R, Callahan P, Encrenaz P, Flamini E, Francescetti G, Gim Y, Hamilton G, Hensley S, Johnson WTK, Kelleher K, Muhleman D, Paillou P, Picardi G, Posa F, Roth L, Seu R, Shaffer S, Vetrella S, West R. The lakes of Titan. Nature 2007; 445:61-4. [PMID: 17203056 DOI: 10.1038/nature05438] [Citation(s) in RCA: 440] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2006] [Accepted: 11/09/2006] [Indexed: 11/09/2022]
Abstract
The surface of Saturn's haze-shrouded moon Titan has long been proposed to have oceans or lakes, on the basis of the stability of liquid methane at the surface. Initial visible and radar imaging failed to find any evidence of an ocean, although abundant evidence was found that flowing liquids have existed on the surface. Here we provide definitive evidence for the presence of lakes on the surface of Titan, obtained during the Cassini Radar flyby of Titan on 22 July 2006 (T16). The radar imaging polewards of 70 degrees north shows more than 75 circular to irregular radar-dark patches, in a region where liquid methane and ethane are expected to be abundant and stable on the surface. The radar-dark patches are interpreted as lakes on the basis of their very low radar reflectivity and morphological similarities to lakes, including associated channels and location in topographic depressions. Some of the lakes do not completely fill the depressions in which they lie, and apparently dry depressions are present. We interpret this to indicate that lakes are present in a number of states, including partly dry and liquid-filled. These northern-hemisphere lakes constitute the strongest evidence yet that a condensable-liquid hydrological cycle is active in Titan's surface and atmosphere, in which the lakes are filled through rainfall and/or intersection with the subsurface 'liquid methane' table.
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Affiliation(s)
- E R Stofan
- Proxemy Research, Rectortown, Virginia 20140, USA.
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Elachi C, Wall S, Janssen M, Stofan E, Lopes R, Kirk R, Lorenz R, Lunine J, Paganelli F, Soderblom L, Wood C, Wye L, Zebker H, Anderson Y, Ostro S, Allison M, Boehmer R, Callahan P, Encrenaz P, Flamini E, Francescetti G, Gim Y, Hamilton G, Hensley S, Johnson W, Kelleher K, Muhleman D, Picardi G, Posa F, Roth L, Seu R, Shaffer S, Stiles B, Vetrella S, West R. Titan Radar Mapper observations from Cassini's T3 fly-by. Nature 2006; 441:709-13. [PMID: 16760968 DOI: 10.1038/nature04786] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2005] [Accepted: 04/04/2006] [Indexed: 11/08/2022]
Abstract
Cassini's Titan Radar Mapper imaged the surface of Saturn's moon Titan on its February 2005 fly-by (denoted T3), collecting high-resolution synthetic-aperture radar and larger-scale radiometry and scatterometry data. These data provide the first definitive identification of impact craters on the surface of Titan, networks of fluvial channels and surficial dark streaks that may be longitudinal dunes. Here we describe this great diversity of landforms. We conclude that much of the surface thus far imaged by radar of the haze-shrouded Titan is very young, with persistent geologic activity.
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Affiliation(s)
- C Elachi
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
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Lorenz RD, Wall S, Radebaugh J, Boubin G, Reffet E, Janssen M, Stofan E, Lopes R, Kirk R, Elachi C, Lunine J, Mitchell K, Paganelli F, Soderblom L, Wood C, Wye L, Zebker H, Anderson Y, Ostro S, Allison M, Boehmer R, Callahan P, Encrenaz P, Ori GG, Francescetti G, Gim Y, Hamilton G, Hensley S, Johnson W, Kelleher K, Muhleman D, Picardi G, Posa F, Roth L, Seu R, Shaffer S, Stiles B, Vetrella S, Flamini E, West R. The Sand Seas of Titan: Cassini RADAR Observations of Longitudinal Dunes. Science 2006; 312:724-7. [PMID: 16675695 DOI: 10.1126/science.1123257] [Citation(s) in RCA: 304] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The most recent Cassini RADAR images of Titan show widespread regions (up to 1500 kilometers by 200 kilometers) of near-parallel radar-dark linear features that appear to be seas of longitudinal dunes similar to those seen in the Namib desert on Earth. The Ku-band (2.17-centimeter wavelength) images show approximately 100-meter ridges consistent with duneforms and reveal flow interactions with underlying hills. The distribution and orientation of the dunes support a model of fluctuating surface winds of approximately 0.5 meter per second resulting from the combination of an eastward flow with a variable tidal wind. The existence of dunes also requires geological processes that create sand-sized (100- to 300-micrometer) particulates and a lack of persistent equatorial surface liquids to act as sand traps.
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Affiliation(s)
- R D Lorenz
- Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA.
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Elachi C, Wall S, Allison M, Anderson Y, Boehmer R, Callahan P, Encrenaz P, Flamini E, Franceschetti G, Gim Y, Hamilton G, Hensley S, Janssen M, Johnson W, Kelleher K, Kirk R, Lopes R, Lorenz R, Lunine J, Muhleman D, Ostro S, Paganelli F, Picardi G, Posa F, Roth L, Seu R, Shaffer S, Soderblom L, Stiles B, Stofan E, Vetrella S, West R, Wood C, Wye L, Zebker H. Cassini Radar Views the Surface of Titan. Science 2005; 308:970-4. [PMID: 15890871 DOI: 10.1126/science.1109919] [Citation(s) in RCA: 198] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The Cassini Titan Radar Mapper imaged about 1% of Titan's surface at a resolution of approximately 0.5 kilometer, and larger areas of the globe in lower resolution modes. The images reveal a complex surface, with areas of low relief and a variety of geologic features suggestive of dome-like volcanic constructs, flows, and sinuous channels. The surface appears to be young, with few impact craters. Scattering and dielectric properties are consistent with porous ice or organics. Dark patches in the radar images show high brightness temperatures and high emissivity and are consistent with frozen hydrocarbons.
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Affiliation(s)
- C Elachi
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
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Tzortzakis S, Méchain G, Patalano G, André YB, Prade B, Franco M, Mysyrowicz A, Munier JM, Gheudin M, Beaudin G, Encrenaz P. Coherent subterahertz radiation from femtosecond infrared filaments in air. Opt Lett 2002; 27:1944-1946. [PMID: 18033410 DOI: 10.1364/ol.27.001944] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We report on what is believed to be the first observation of coherent subterahertz (sub-THz) emission from a 1-m string in the atmosphere. The sub-THz pulse emitted by the filamentary structure from an intense IR femtosecond laser pulse is detected perpendicularly to the laser propagation axis by use of two heterodyne detectors at 94+/-1 and 118+/-1GHz . We describe the characteristics of this emission and show evidence of constructive interference between two separate strings.
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