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14 results on '"individual objects"'

1. Discovery of CH3CHCO in TMC-1 with the QUIJOTE line survey

Author

R. Fuentetaja, C. Bermúdez, C. Cabezas, M. Agúndez, B. Tercero, N. Marcelino, J. R. Pardo, L. Margulès, R. A. Motiyenko, J.-C. Guillemin, P. de Vicente, J. Cernicharo, Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Universidad de Valladolid [Valladolid] (UVa), Instituto Geografico Nacional (IGN), Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 (PhLAM), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Ministerio de Ciencia e Innovacion of Spain (MICIU) [PID2019-106110GB-I00, ERC-2013-Syg-610256-NANOCOSMOS], ERC [CONVREC-2021-317], Ministerio de Universidades [PID2019-107115GB-C21], and [PID2019-106235GB-I00]

Subjects
individual objects, molecular data, astrochemistry, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, TMC-1, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), identification, [CHIM]Chemical Sciences, line, molecules, ISM
Abstract

We report the detection of methyl ketene towards TMC-1 with the QUIJOTE line survey. Nineteen rotational transitions with rotational quantum numbers ranging from J = 3 up to J = 5 and Ka ≤ 2 were identified in the frequency range 32.0–50.4 GHz, 11 of which arise above the 3σ level. We derived a column density for CH3CHCO of N = 1.5 × 1011 cm−2 and a rotational temperature of 9 K. Hence, the abundance ratio between ketene and methyl ketene, CH2CO/CH3CHCO, is 93. This species is the second C3H4O isomer detected. The other, trans-propenal (CH2CHCHO), corresponds to the most stable isomer and has a column density of N = (2.2 ± 0.3)×1011 cm−2, which results in an abundance ratio CH2CHCHO/CH3CHCO of 1.5. The next non-detected isomer with the lowest energy is cis-propenal, which is therefore a good candidate for future discovery. We have carried out an in-depth study of the possible gas-phase chemical reactions involving methyl ketene to explain the abundance detected, achieving good agreement between chemical models and observations.

Published
2023

2. The sharp ALMA view of infall and outflow in the massive protocluster G31.41+0.31

Author

M. T. Beltrán, V. M. Rivilla, R. Cesaroni, D. Galli, L. Moscadelli, A. Ahmadi, H. Beuther, S. Etoka, C. Goddi, P. D. Klaassen, R. Kuiper, M. S. N. Kumar, A. Lorenzani, T. Peters, Á. Sánchez-Monge, P. Schilke, F. van der Tak, S. Vig, and Astronomy

Subjects
Interferometric, stars: formation, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Stars - massive, Physik (inkl. Astronomie), Astrophysics - Astrophysics of Galaxies, Techniques, Individual objects, stars: massive, G31.41+0.31, Space and Planetary Science, techniques: interferometric, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Solar and Stellar Astrophysics, Stars - formation, Astrophysics::Earth and Planetary Astrophysics, ISM: individual objects: G31.41+0.31, Astrophysics::Galaxy Astrophysics, ISM
Abstract

Context. To better understand the formation of high-mass stars, it is fundamental to investigate how matter accretes onto young massive stars, how it is ejected, and how all this differs from the low-mass case. The massive protocluster G31.41+0.31 is the ideal target to study all these processes because observations at millimeter and centimeter wavelengths have resolved the emission of the Main core into at least four massive dust continuum sources, named A, B, C, and D, within 1" or 0.018 pc, and have identified signatures of infall and several outflows associated with the core. Aims. We study the interplay between infall and outflow in G31.41+0.31 by investigating at a spatial resolution of a few 100 au their properties and their possible impact on the core. Methods. We carried out molecular line observations of typical high-density tracers, such as CH3CN or H2CO, and shock and outflow tracers, such as SiO, with ALMA at 1.4 mm that achieved an angular resolution of 0.09" (340 au). Results. The observations have revealed inverse P-Cygni profiles in CH3CN and H2CO toward the four sources embedded in the Main core, suggesting that all of them are undergoing collapse. The infall rates, estimated from the red-shifted absorption are on the order of 1E-2 Msun/yr. The individual infall rates imply that the accretion timescale of the Main core is an order of magnitude smaller than its rotation timescale. This confirms that rotating toroids such as the G31 Main core are non-equilibrium, transient collapsing structures that need to be constantly replenished with fresh material from a large-scale reservoir. For sources B, C, and D, the infall could be accelerating inside the sources, while for source A, the presence of a second emission component complicates the interpretation. The SiO observations have revealed the presence of at least six outflows in the G31.41+0.31 star-forming region, ..., 17 pages, 9 figures, 2 tables. Accepted by A&A

Published
2022

3. X-ray observations of the hot phase in Sagittarius A.

Author

Różańska1, A., Mróz, P., Mościbrodzka, M., Sobolewska, M., and Adhikari, T. P.

Subjects
*SAGITTARIUS A* (Astronomy), *GALACTIC center, *HIGH temperature plasmas, *MOLECULAR clouds, *SURFACE brightness (Astronomy), *THERMAL plasmas
Abstract

Context. We analyse 134 ks Chandra ACIS-I observations of the Galactic Centre (GC) performed in July 2011. The X-ray image with the field of view 17' x 17' contains the hot plasma surrounding the Sgr A*. The obtained surface brightness map allows us to fit the Bondi hot accretion flow to the innermost hot plasma around the GC. Aims. Contrary to the XMM-Newton data where a strong 6.4 keV iron line was observed andinterpreted as a reflection from molecular clouds, we search here for the diffuse X-ray emission with prominent 6.69 keV iron line. We found a surface brightness profile that allowed us to determine the stagnation radius of the flow around Sgr A*. Methods. We fitted spectra from the region up to 5'' from Sgr A* using a thermal bremsstrahlung model and four Gaussian profiles responsible for Kα emission lines of Fe, S, Ar, and Ca. The X-ray surface brightness profile up to 3'' from Sgr A* found in our data image was successfully fitted with the dynamical model of Bondi spherical accretion. Results. We show that the temperature of the hot plasma derived from our spectral fitting is of the order of 2.2-2.7 keV depending on the choice of background. By modelling the surface brightness profile, we derived the temperature and number density profiles in the vicinity of the black hole. The best fitted model of spherical Bondi accretion shows that this type of flow works only up to 3'' and implies that the outer plasma density and temperature are n™1 = 18.3 ± 0.1 cm-3 and re™1 = 3.5 ± 0.3 keV, respectively. Conclusions. We show that the Bondi flow can reproduce observed surface brightness profiles up to 3'' from Sgr A* in the Galactic centre. This result strongly suggests the position of stagnation radius in the complicated dynamics around GC. The temperature at the outer radius of the flow is higher by 1 keV than the value found by our spectral fitting of thermal plasma within the circle of 5''. The Faraday rotation computed from our model towards the pulsar PSR J1745-2900 near the GC agrees with the observed one, recently reported. We speculate here that the emission lines observed in spectra up to 5'' can be interpreted as the reflection of the radiation from two-phase regions occurring at distances between 3-5'' of the flow. The hot plasma in Sgr A* illuminated in the past by a strong radiation field may be a seed for thermal instabilities and eventual strong clumpiness. [ABSTRACT FROM AUTHOR]

Published
2015
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4. Bipolar HII regions -- Morphology and star formation in their vicinity.

Subjects
*STAR formation, *STAR clusters, *SURFACE morphology, *INTERSTELLAR medium, *PHOTODISSOCIATION
Abstract

Aims. Our goal is to identify bipolar HII regions and to understand their morphology, their evolution, and the role they play in the formation of new generations of stars. Methods. We use the Spitzer-GLIMPSE, -MIPSGAL, and Herschel-Hi-GAL surveys to identify bipolar HII regions, looking for (ionized) lobes extending perpendicular to dense filamentary structures. We search for their exciting star(s) and estimate their distances using near-IR data from the 2MASS or UKIDSS surveys. Dense molecular clumps are detected using Herschel-SPIRE data, and we estimate their temperature, column density, mass, and density. MALT90 observations allow us to ascertain their association with the central HII region (association based on similar velocities). We identify Class 0/I young stellar objects (YSOs) using their Spitzer and Herschel-PACS emissions. These methods will be applied to the entire sample of candidate bipolar H II regions to be presented in a forthcoming paper. Results. This paper focuses on two bipolar HII regions, one that is especially interesting in terms of its morphology, G319.88+00.79, and one in terms of its star formation, G010.32-00.15. Their exciting clusters are identified and their photometric distances estimated to be 2.6 kpc and 1.75 kpc, respectively; thus G010.32-00.15 (known as W31 north) lies much closer than previously assumed. We suggest that these regions formed in dense and flat structures that contain filaments. They have a central ionized region and ionized lobes extending perpendicular to the parental cloud. The remains of the parental cloud appear as dense (more than 104 cm-3) and cold (14-17 K) condensations. The dust in the photodissociation regions (in regions adjacent to the ionized gas) is warm (19-25 K). Dense massive clumps are present around the central ionized region. G010.32-00.14 is especially remarkable because five clumps of several hundred solar masses surround the central H II region; their peak column density is a few 1023 cm-2, and the mean density in their central regions reaches several 105 cm-3. Four of them contain at least one massive YSO (including an ultracompact HII region and a high-luminosity Class I YSO); these clumps also contain extended green objects (EGOs) and Class II methanol masers. This morphology suggests that the formation of a second generation of massive stars has been triggered by the central bipolar H II region. It occurs in the compressed material of the parental cloud. [ABSTRACT FROM AUTHOR]

Published
2015
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5. Successive deuteration in low-mass star-forming regions: The case of D2-methanol (CHD2OH) in IRAS 16293-2422

Author

Drozdovskaya, Maria N., Coudert, Laurent H., Margulès, Laurent, Coutens, Audrey, Jørgensen, Jes K., Manigand, Sébastien, Center for Space and Habitability, Institut des Sciences Moléculaires d'Orsay (ISMO), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 (PhLAM), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Physique Moléculaire aux Interfaces (PMI), Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Niels Bohr Institute [Copenhagen] (NBI), Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH), 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, 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
individual objects, ALMA-PILS SURVEY, 530 Physics, FOS: Physical sciences, LINE SURVEY, 1ST DETECTION, FAR-INFRARED SPECTRUM, astrochemistry -ISM, molecules -Stars, ISM [submillimeter], INTERNAL AXIS APPROACH, Solar and Stellar Astrophysics (astro-ph.SR), molecules [ISM], protostars [stars], ISM, Earth and Planetary Astrophysics (astro-ph.EP), formation -ISM, formation [stars], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], astrochemistry, 520 Astronomy, H-D-SUBSTITUTION, Astronomy and Astrophysics, TORSIONAL ROTATIONAL SPECTRA, 500 Science, Astrophysics - Astrophysics of Galaxies, DEUTERIUM FRACTIONATION, protostars -Stars, IRAS 16293-2422 -Submillimeter, individual objects: IRAS 16293-2422 [ISM], Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), ORGANIC-MOLECULES, ASYMMETRIC ASYMMETRIC MOLECULES, Astrophysics - Earth and Planetary Astrophysics
Abstract

Accurate quantification of the column density of di-deuterated methanol is a key missing puzzle piece in the otherwise thoroughly constrained family of D-bearing methanol in the deeply embedded low-mass protostellar system and astrochemical template source IRAS16293-2422. A spectroscopic dataset for astrophysical purposes is built for CHD$_{2}$OH and made publicly available to facilitate accurate characterization of this species in astrochemical surveys. The newly computed line list and partition function are used to search for CHD$_{2}$OH towards IRAS16293-2422 A and B in data from ALMA-PILS. Only non-blended, optically thin lines of CHD$_{2}$OH are used for the synthetic spectral fitting. The constructed spectroscopic database contains line frequencies and strengths for 7417 transitions in the 0 to 500 GHz frequency range. ALMA-PILS observations in the 329-363 GHz range are used to identify 105 unique, non-blended, optically thin line frequencies of CHD$_{2}$OH for synthetic spectral fitting. The derived excitation temperatures and column densities yield high D/H ratios of CHD$_{2}$OH in IRAS 16293-2422 A and B of 7.5$\pm$1.1% and 7.7$\pm$1.2%, respectively. Deuteration in IRAS 16293-2422 is not higher than in other low-mass star-forming regions. Di-deuterated molecules consistently have higher D/H ratios than their monodeuterated counterparts in all low-mass protostars, which may be a natural consequence of H-D substitution reactions as seen in laboratory experiments. The Solar System's natal cloud, as traced by comet 67P/Churyumov-Gerasimenko, may have had a lower initial abundance of D, been warmer than the cloud of IRAS16293-2422, or been partially reprocessed. In combination with accurate spectroscopy, a careful spectral analysis, and a consideration of the underlying assumptions, successive deuteration is a robust window on the physicochemical provenance of star-forming systems., Accepted for publication in A&A; 24 pages, 18 figures, 3 tables; the full line list is made available as an electronic Table at the Centre de Donn\'ees astronomiques de Strasbourg (CDS) with association to this A&A article

Published
2022

6. Revised spectroscopic parameters of SH+ from ALMA* and IRAM 30m** observations***.

Author

Müller, Holger S. P., Goicoechea, Javier R., Cernicharo, José, Agúndez, Marcelino, Pety, Jérôme, Cuadrado, Sara, Gerin, Maryvonne, Dumas, Gaëlle, and Chapillon, Edwige

Subjects
*HYDRIDES, *HYPERFINE structure, *RADIO lines, *INTERSTELLAR medium
Abstract

Hydrides represent the first steps of interstellar chemistry. Sulfanylium (SH+), in particular, is a key tracer of energetic processes. We used ALMA and the IRAM 30m telescope to search for the lowest frequency rotational lines of SH+ toward the Orion Bar, the prototypical photo-dissociation region illuminated by a strong UV radiation field. On the basis of previous Herschel/HIFI observations of SH+, we expected to detect emission of the two SH+ hyperfine structure (HFS) components of the NJ = 10-01 fine structure (FS) component near 346 GHz. While we did not observe any lines at the frequencies predicted from laboratory data, we detected two emission lines, each ∼15MHz above the SH+ predictions and with relative intensities and HFS splitting expected for SH+. The rest frequencies of the two newly detected lines are more compatible with the remainder of the SH+ laboratory data than the single line measured in the laboratory near 346 GHz and previously attributed to SH+. Therefore, we assign these new features to the two SH+ HFS components of the NJ = 10-01 FS component and re-determine its spectroscopic parameters, which will be useful for future observations of SH+, in particular if its lowest frequency FS components are studied. Our observations demonstrate the suitability of these lines for SH+ searches at frequencies easily accessible from the ground. [ABSTRACT FROM AUTHOR]

Published
2014
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7. On the radiation driven alignment of dust grains: Detection of the polarization hole in a starless core.

Author

Alves, F. O., Frau, P., Girart, J. M., Franco, G. A. P., Santos, F. P., and Wiesemeyer, H.

Subjects
*STELLAR radiation, *LINEAR polarization, *INTERSTELLAR medium, *STAR formation, *STELLAR polarimetry
Abstract

Aims. We aim to investigate the polarization properties of a starless core in an early evolutionary stage. Linear polarization data reveal the properties of the dust grains in the distinct phases of the interstellar medium. Our goal is to investigate how the polarization degree and angle correlate with the cloud and core gas. Methods. We use optical, near infrared, and submillimeter polarization observations on the starless object Pipe-109 in the Pipe nebula. Our data cover a physical scale range of 0.08 to 0.4 pc, comprising the dense gas, envelope, and the surrounding cloud. Results. The cloud polarization is well traced by the optical data. The near infrared polarization is produced by a mixed population of grains from the core border and the cloud gas. The optical and near infrared polarization toward the cloud reaches the maximum possible value and saturates with respect to the visual extinction. The core polarization is predominantly traced by the submillimeter data and has a steep decrease with respect to the visual extinction. Modeling of the submillimeter polarization indicates a magnetic field main direction projected onto the plane-of-sky and loss of grain alignment for densities higher than 6 × 104 cm-3 (or AV > 30 mag). Conclusions. The object is immersed in a magnetized medium with a very ordered magnetic field. The absence of internal source of radiation significantly affects the polarization efficiencies in the core, creating a polarization hole at the center of the starless core. This result supports the theory of dust grain alignment via radiative torques. [ABSTRACT FROM AUTHOR]

Published
2014
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8. First spectrally-resolved H2 observations towards HH 54* Low H2O abundance in shocks.

Author

Santangelo, G., Antoniucci, S., Nisini, B., Codella, C., Bjerkeli, P., Giannini, T., Lorenzani, A., Lundin, L. K., Cabrit, S., Calzoletti, L., Liseau, R., Neufeld, D., Tafalla, M., and Van Dishoeck, E. F.

Subjects
*LOW mass stars, *STAR observations, *COSMIC abundances, *INFRARED astronomy, *STAR formation, *INTERSTELLAR medium
Abstract

Context. Herschel observations suggest that the H2O distribution in outflows from low-mass stars resembles the H2 emission. It is still unclear which of the different excitation components that characterise the mid- and near-IR H2 distribution is associated with H2O. Aims. The aim is to spectrally resolve the different excitation components observed in the H2 emission. This will allow us to identify the H2 counterpart associated with H2O and finally derive directly an H2O abundance estimate with respect to H2. Methods. We present new high spectral resolution observations of H2 0-0 S(4), 0-0 S(9), and 1-0 S(1) towards HH 54, a bright nearby shock region in the southern sky. In addition, new Herschel/HIFI H2O (212-101) observations at 1670 GHz are presented. Results. Our observations show for the first time a clear separation in velocity of the different H2 lines: the 0-0 S(4) line at the lowest excitation peaks at -7 kms-1, while the more excited 0-0 S(9) and 1-0 S(1) lines peak at -15 km s-1. H2O and high-J CO appear to be associated with the H2 0-0 S(4) emission, which traces a gas component with a temperature of 700-1000 K. The H2O abundance with respect to H2 0-0 S(4) is estimated to be X(H2O) < 1.4 × 10-5 in the shocked gas over an area of 13" . Conclusions. We resolve two distinct gas components associated with the HH 54 shock region at different velocities and excitations. This allows us to constrain the temperature of the H2O emitting gas (≤1000 K) and to derive correct estimates of H2O abundance in the shocked gas, which is lower than what is expected from shock model predictions. [ABSTRACT FROM AUTHOR]

Published
2014
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9. Deuterated methanol in the pre-stellar core L1544.

Author

Bizzocchi, L., Caselli, P., Spezzano, S., and Leonardo, E.

Subjects
*DEUTERATION, *METHANOL, *GRAVITATIONAL collapse, *PROTOSTARS, *INTERSTELLAR medium, *MOLECULAR clouds, *RADIO lines, *RADIATIVE transfer
Abstract

Context. High methanol (CH3OH) deuteration has been revealed in Class 0 protostars with the detection of singly, doubly, and even triply D-substituted forms. Methanol is believed to form during the pre-collapse phase via gas-grain chemistry and then eventually injected into the gas when the heating produced by the newly formed protostar sublimates the grain mantles. The molecular deuterium fraction of the warm gas is thus a relic of the cold pre-stellar era and provides hints of the past history of the protostars. Aims. Pre-stellar cores represent the preceding stages in the process of star formation. We aim at measuring methanol deuteration in L1544, a prototypical dense and cold core on the verge of gravitational collapse. The aim is to probe the deuterium fractionation process while the "frozen" molecular reservoir is accumulated onto dust grains. Methods. Using the IRAM 30m telescope, we mapped the methanol emission in the pre-stellar core L1544 and observed singly deuterated methanol (CH2DOH and CH3OD) towards the dust peak of L1544. Non-LTE radiative transfer modelling was performed on three CH3OH emissions lines at 96.7 GHz, using a Bonnor-Ebert sphere as a model for the source. We have also assumed a centrally decreasing abundance profile to take the molecule freeze-out in the inner core into account. The column density of CH2DOH was derived assuming LTE excitation and optically thin emission. Results. The CH3OH emission has a highly asymmetric morphology, resembling a non-uniform ring surrounding the dust peak, where CO is mainly frozen onto dust grains. The observations provide an accurate measure of methanol deuteration in the cold pre-stellar gas. The derived abundance ratio is [CH2DOH]/[CH3OH] = 0.10 ± 0.03, which is significantly smaller than the ones found in lowmass Class 0 protostars and smaller than the deuterium fraction measured in other molecules towards L1544. The singly-deuterated form CH3OD was not detected at 3σ sensitivity of 7 mKkms-1, yielding a lower limit of [CH2DOH]/[CH3OD] ≥ 10, consistent with previous measurements towards Class 0 protostars. Conclusions. The low deuterium fractionation observed in L1544 and the morphology of the CH3OH emission suggest that we are mainly tracing the outer parts of the core, where CO just started to freeze-out onto dust grains. [ABSTRACT FROM AUTHOR]

Published
2014
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10. Seeds of Life in Space (SOLIS): VI. Chemical evolution of sulfuretted species along the outflows driven by the low-mass protostellar binary NGC 1333-IRAS4A

Author

V. Taquet, C. Codella, M. De Simone, A. López-Sepulcre, J. E. Pineda, D. Segura-Cox, C. Ceccarelli, P. Caselli, A. Gusdorf, M. V. Persson, F. Alves, E. Caux, C. Favre, F. Fontani, R. Neri, Y. Oya, N. Sakai, C. Vastel, S. Yamamoto, R. Bachiller, N. Balucani, E. Bianchi, L. Bizzocchi, A. Chacón-Tanarro, F. Dulieu, J. Enrique-Romero, S. Feng, J. Holdship, B. Lefloch, A. Jaber Al-Edhari, I. Jiménez-Serra, C. Kahane, V. Lattanzi, J. Ospina-Zamudio, L. Podio, A. Punanova, A. Rimola, I. R. Sims, S. Spezzano, L. Testi, P. Theulé, P. Ugliengo, A. I. Vasyunin, F. Vazart, S. Viti, A. Witzel, Istituto Nazionale di Astrofisica (INAF), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Max Planck Institute for Extraterrestrial Physics (MPE), Max-Planck-Gesellschaft, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Chalmers University of Technology [Göteborg], Centre National d'Études Spatiales [Toulouse] (CNES), 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), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), The University of Tokyo (UTokyo), RIKEN - Institute of Physical and Chemical Research [Japon] (RIKEN), Instituto Geografico Nacional (IGN), National Astronomical Observatories [Beijing] (NAOC), Chinese Academy of Sciences [Beijing] (CAS), University College of London [London] (UCL), Spanish National Research Council (CSIC), Ural Federal University [Ekaterinburg] (UrFU), Departament de Química [Barcelona] (UAB), Universitat Autònoma de Barcelona (UAB), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), European Southern Observatory (ESO), Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Università degli studi di Torino (UNITO), IRAM PdBI/NOEMA Interferometer [V05B, V010, U003, L15AA], MPG (Germany)Max Planck Society, IGN (Spain), European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grantEuropean Union (EU) [664931], PRIN-INAF 2016 'The Cradle of Life -GENESIS-SKA (General Conditions in Early Planetary Systems for the rise of life with SKA)', European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programmeEuropean Research Council (ERC) [741002], European MARIE SKLODOWSKA-CURIE ACTIONS under the European Union's Horizon 2020 research and innovation programme [811312], French National Research Agency of the 'Origin of Life' project of the Universite Grenoble-AlpesFrench National Research Agency (ANR) [ANR-15-IDEX-02], INSU/CNRS (France)Centre National de la Recherche Scientifique (CNRS), Ceccarelli, C. [0000-0001-9664-6292], Balucani, N. [0000-0001-5121-5683], Rimola, A. [0000-0002-9637-4554], Al Edhari, A. J. [0000-0003-4089-841X], De Oliveira Alves, F. [0000-0002-7945-064X], Lefloch, B. [0000-0002-9397-3826], Persson, M. V. [0000-0002-1100-5734], Bachiller, R. [0000-0002-5331-5386], Pineda, J. [0000-0002-3972-1978], Segura Cox, D. [0000-0003-3172-6763], IRAM PdBI/NOEMA Interferometer, V05B V010 U003 L15AA, Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), 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), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Università degli studi di Torino = University of Turin (UNITO), ANR-15-IDEX-0002,UGA,IDEX UGA(2015), Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737, Agence Nationale de la Recherche (ANR), European Research Council (ERC), 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)-CY Cergy Paris Université (CY), Taquet V., Codella C., De Simone M., Lopez-Sepulcre A., Pineda J.E., Segura-Cox D., Ceccarelli C., Caselli P., Gusdorf A., Persson M.V., Alves F., Caux E., Favre C., Fontani F., Neri R., Oya Y., Sakai N., Vastel C., Yamamoto S., Bachiller R., Balucani N., Bianchi E., Bizzocchi L., Chacon-Tanarro A., Dulieu F., Enrique-Romero J., Feng S., Holdship J., Lefloch B., Jaber Al-Edhari A., Jimenez-Serra I., Kahane C., Lattanzi V., Ospina-Zamudio J., Podio L., Punanova A., Rimola A., Sims I.R., Spezzano S., Testi L., Theule P., Ugliengo P., Vasyunin A.I., Vazart F., Viti S., and Witzel A.

Subjects
MILLIMETER ARRAYS, Binary number, CHEMICAL EVOLUTION, ISM: molecule, Astrophysics, Space (mathematics), 01 natural sciences, ISM: abundances, CHEMICAL CONDITIONS, ISM jets and outflows, ABUNDANCES [ISM], jets and outflows -ISM, CHEMICAL DIFFERENTIATION, 010303 astronomy & astrophysics, ISM abundances, Astrochemistry, Physics, [PHYS]Physics [physics], ASTROCHEMISTRY, Shock (fluid dynamics), INTERSTELLAR ICE, SUBMILLIMETRE TELESCOPES, NGC 1333-IRAS4A, ISM: abundance, ISM: molecules, stars formation, Radial velocity, ISM: jets and outflows, ISM individual objects NGC1333-IRAS4A, ISM: individual objects: NGC 1333-IRAS4A, CHEMICAL HISTORY, Low Mass, molecules -stars, Stars: formation, individual objects, JETS AND OUTFLOWS [ISM], FOS: Physical sciences, Context (language use), INDIVIDUAL OBJECTS: NGC 1333-IRAS4A [ISM], SILICON COMPOUNDS, SULFUR DIOXIDE, ISM molecules, astrochemistry -ISM, FORMATION [STARS], 0103 physical sciences, Protostar, ISM: jets and outflow, formation -ISM, 010308 nuclear & particles physics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, abundances -ISM, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), MOLECULES [ISM], Outflow, MOLECULAR OUTFLOWS, STARS
Abstract

Context. Low-mass protostars drive powerful molecular outflows that can be observed with millimetre and submillimetre telescopes. Various sulfuretted species are known to be bright in shocks and could be used to infer the physical and chemical conditions throughout the observed outflows. Aims. The evolution of sulfur chemistry is studied along the outflows driven by the NGC 1333-IRAS4A protobinary system located in the Perseus cloud to constrain the physical and chemical processes at work in shocks. Methods. We observed various transitions from OCS, CS, SO, and SO2 towards NGC 1333-IRAS4A in the 1.3, 2, and 3 mm bands using the IRAM NOrthern Extended Millimeter Array and we interpreted the observations through the use of the Paris-Durham shock model. Results. The targeted species clearly show different spatial emission along the two outflows driven by IRAS4A. OCS is brighter on small and large scales along the south outflow driven by IRAS4A1, whereas SO2 is detected rather along the outflow driven by IRAS4A2 that is extended along the north east-south west direction. SO is detected at extremely high radial velocity up to + 25 km s-1 relative to the source velocity, clearly allowing us to distinguish the two outflows on small scales. Column density ratio maps estimated from a rotational diagram analysis allowed us to confirm a clear gradient of the OCS/SO2 column density ratio between the IRAS4A1 and IRAS4A2 outflows. Analysis assuming non Local Thermodynamic Equilibrium of four SO2 transitions towards several SiO emission peaks suggests that the observed gas should be associated with densities higher than 105 cm-3 and relatively warm (T > 100 K) temperatures in most cases. Conclusions. The observed chemical differentiation between the two outflows of the IRAS4A system could be explained by a different chemical history. The outflow driven by IRAS4A1 is likely younger and more enriched in species initially formed in interstellar ices, such as OCS, and recently sputtered into the shock gas. In contrast, the longer and likely older outflow triggered by IRAS4A2 is more enriched in species that have a gas phase origin, such as SO2., With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737)

Published
2020

11. Rotational spectroscopic study and astronomical search for propiolamide in Sgr B2(N)

Author

Elena R. Alonso, Jean-Claude Guillemin, Arnaud Belloche, Karl M. Menten, S. Mata, Robin T. Garrod, A. Jabri, Iker León, José L. Alonso, Holger S. P. Müller, Lucie Kolesniková, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Czech Science Foundation, Junta de Castilla y León, European Research Council, European Commission, Fundación Biofísica Bizkaia, Centre National de la Recherche Scientifique (France), Centre National D'Etudes Spatiales (France), University of the Basque Country/Euskal Herriko Unibertsitatea (UPV/EHU), University of Chemistry and Technology Prague (UCT Prague), Max-Planck-Institut für Radioastronomie (MPIFR), Spanish National Research Council (CSIC), Universidad de Valladolid [Valladolid] (UVa), University of Virginia, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Universität zu Köln = University of Cologne, The funding from Ministerio de Ciencia e Innovación (CTQ2016-76393-P and PID2019-111396GB-I00), Czech Science Foundation (GACR, grant 19-25116Y), Junta de Castilla y León (Grants VA077U16 and VA244P20), and European Research Council under the European Union’s Seventh Framework Programme ERC-2013-SyG, Grant Agreement n. 610256 NANOCOSMOS are gratefully acknowledged. E.R.A. thanks Fundación Biofísica Bizkaia (FBB) for a postdoctoral contract. J.C.G. thanks the program Physique et Chimie du Milieu Interstellaire (INSU-CNRS) and the Centre National d’Etudes Spatiales (CNES). Part of this work has been carried out within the Collaborative Research Centre 956, sub-project B3, funded by the Deutsche Forschungsgemeinschaft (DFG) – project ID 184018867. R.T.G. acknowledges support from the National Science Foundation (grant No. AST 19-06489)., European Project: 610256,EC:FP7:ERC,ERC-2013-SyG,NANOCOSMOS(2014), University of Virginia [Charlottesville], Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), and Universität zu Köln

Subjects
Astrochemistry, Line: identification, FOS: Physical sciences, Context (language use), Astrophysics, 01 natural sciences, Submillimeter Array, Article, Spectral line, Astronomical databases: miscellaneous, chemistry.chemical_compound, 0103 physical sciences, [CHIM]Chemical Sciences, Cyanoacetylene, 010303 astronomy & astrophysics, Hyperfine structure, Physics, 010304 chemical physics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM: molecules, Sagittarius B2 – astronomical databases, Molecules – line, Individual objects, Miscellaneous, 3. Good health, chemistry, Astrochemistry – ISM, Identification – ISM, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Excited state, Rotational spectroscopy, Astro-ph.GA, ISM: individual objects: Sagittarius B2
Abstract

For all the amides detected in the interstellar medium (ISM), the corresponding nitriles or isonitriles have also been detected in the ISM, some of which have relatively high abundances. Among the abundant nitriles for which the corresponding amide has not yet been detected is cyanoacetylene (HCCCN), whose amide counterpart is propiolamide (HCCC(O)NH2)., The funding from Ministerio de Ciencia e Innovación (CTQ2016-76393-P and PID2019-111396GB-I00), Czech Science Foundation (GACR, grant 19-25116Y), Junta de Castilla y León (Grants VA077U16 and VA244P20), and European Research Council under the European Union’s Seventh Framework Programme ERC-2013-SyG, Grant Agreement n. 610256 NANOCOSMOS are gratefully acknowledged. E.R.A. thanks Fundación Biofísica Bizkaia (FBB) for a postdoctoral contract. J.C.G. thanks the program Physique et Chimie du Milieu Interstellaire (INSU-CNRS) and the Centre National d’Etudes Spatiales (CNES).

Published
2021

12. New results on the massive star-forming region S106 by BEAR spectro-imagery

Author

C. Joblin, Bernard Noël, T. Paumard, Jean-Pierre Maillard, 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), 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), and Université Fédérale Toulouse Midi-Pyrénées

Subjects
stars, formation -ISM, individual objects, Physics, interferometers -HII regionsastrochemistry, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Stellar mass, 010308 nuclear & particles physics, Star formation, Molecular cloud, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Sh 2-106 -instrumentation, Ion, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Stars, 13. Climate action, Space and Planetary Science, Excited state, 0103 physical sciences, Emission spectrum, Spectral resolution, 010303 astronomy & astrophysics
Abstract

As a typical example of interaction of a massive star with its parent cloud, the close environment of S106 IR in the star-forming region S106 was observed at high spectral resolution (~16 km s -1 ). Integral field spectroscopy with BEAR, an imaging Fourier Transform Spectrometer (FTS), on a field of ~40´´in diameter, in the H 2 1–0 S (1), 2–1 S (1), Br γ , $\ion{He}{i}$ and [$\ion{Fe}{iii}$] lines. From the data several maps were obtained: intensity, velocity and linewidth in the Br γ and the H 2 1–0 S (1) line, 1–0 S (1)/2–1 S (1) line ratio, and continuum emission at 2.1 μ m. From the latter, about twenty low-mass stars were detected with photometry in this band, and an estimate of their mass was made leading to the conclusion that S106 is a site of formation of mainly sub-solar mass stars. The intensity structure of the excited molecular gas H 2 was found to be clumpy while the velocity is almost uniformely at $v_{{\rm LSR}}$ $\simeq$ 1.5 km s -1 except to the south where the velocity reaches up to 15 km s -1 in a zone limited by the long edge of a rectangular hole in the emission. The H 2 line ratio map with values from 1 to 9 implies that UV-absorption and shocks are participating in the excitation process. A PDR model with a temperature of 3700 K for S106 IR was used to retrieve the H 2 gas density and temperature. The density was found to vary between 1 and 3.5 $\times$ 10 5 cm -3 with corresponding temperatures between 660 and 1240 K. The study of the linewidth distribution indicates for most of the gas a supersonic turbulence with a mean contribution to the observed profiles of ≥ 6 km s -1 . Turbulence is likely to be responsible for the observed clumpy structure of the excited gas. Point-like spots with a linewidth as high as 30 km s -1 in one position are detected, which may be vortices in the molecular gas. The $\ion{H}{ii}$ region probed by Br γ shows a broad range of velocity, from -45 to +80 km s -1 , organized in velocity structures that correspond to two pairs of large, bipolar outflows originating from the massive source, not directed along the axis of the $\ion{H}{ii}$ region. Emission lines of $\ion{He}{i}$ and [$\ion{Fe}{iii}$] are detected in a bright area to the southwest of S106 IR, with point-like structures suggesting photoevaporating clumps. From the velocity data, a 3-D model of the environment of S106 IR is proposed. S106 is an example of an evolved $\ion{H}{ii}$ region seen face-on. The central source located at the edge of its parent molecular cloud has carved an expanding cylinder of turbulent, atomic gas of $\simeq$0.1 pc in radius. This massive object was formed by an accretion disk process. The disk is still present and the bipolar outflows are remnants of the massive star activity. A time scale of 1400 yr is estimated for the most recent event. A thin and quiescent clumpy layer of warm H 2 marks the transition of the $\ion{H}{ii}$ region to the molecular cloud. From the data, there are locally no signs of ongoing star formation.

Published
2005

13. SEARCH FOR THE 1.67 MU-M PAH EMISSION BAND - MORE UPPER LIMITS

Subjects
PLANETARY NEBULAE, HE-2-77, CONTINUUM EMISSION, INTERSTELLAR MEDIUM, INDIVIDUAL, SPECTROSCOPY, IRAS SOURCES, RED RECTANGLE, INFRARED-EMISSION, FEATURES, DUST, INDIVIDUAL OBJECTS, ORION BAR, POLYCYCLIC AROMATIC-HYDROCARBONS, CARBON, EXTINCTION, SPECTRA, NEBULAE, INTERSTELLAR DUST
Abstract

In an attempt to further resolve the origin and excitation mechanism of the unidentified infrared emission bands, we have obtained high resolution spectroscopy in the H-band for three objects with strong 3.28 and 3.4 mu m emission features. In the scenario of highly vibrational excited, isolated, polycyclic aromatic hydrocarbons a broad band resonance at about 1.67 mu m with an intensity of I-3.4/I-1.67 less than or equal to 6 has been predicted, that should be detectable for our three objects: the Orion bar at position 4, He2-77 and the Red Rectangle. However, this prediction has not been confirmed by us. Our upper limits show that the intensity of the second harmonic should be at least 48 times weaker than the intensity of the 3.4 mu m C-H stretching mode. We conclude that both the hot band theory and the explanation that the excitation of the 3.4 mu m feature is due to molecular side groups is questionable. More laboratory data such as measurements of the first overtone emission of PAH structures like cyclopropylidene (C3H2) and phenanthereneare (C10H14) are needed.

Published
1993

14. OH and H2O maser variations in W33B

Author

Chiappini, C., Anders, F., Rodrigues, T., Miglio, A., Montalban, J., Mosser, B., Girardi, L., Valentini, M., Noels, A., Morel, T., Minchev, I., Steinmetz, M., Santiago, B., Schultheis, M., Martig, M., da Costa, L., Maia, M., Allende Prieto, C., de Assis Peralta, R., Hekker, S., Themessl, N., Kallinger, T., Garcia, R., Mathur, S., Baudin, F., Beers, T., Cunha, K., Harding, P., Holtzman, J., Majewski, S., Mészáros, Sz., Nidever, D., Pan, K., Schiavon, R., Shetrone, M., Schneider, D., Stassun, K., Colom, P., Lekht, E., Pashchenko, M., Rudnitskij, G., Leibniz-Institut für Astrophysik Potsdam (AIP), Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, 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), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Département d'astrophysique, Géophysique et Océanographie (AGO), Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Liverpool John Moores University (LJMU), Laboratoire Géosciences Océan (LGO), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Mullard Space Science Laboratory (MSSL), University College of London [London] (UCL), School of Physics and Astronomy, University of Birmingham [Birmingham], Institute for Astronomy [Vienna], University of Vienna [Vienna], Institut de Physique du Globe de Paris (IPG Paris), Space Science Institute [Boulder] (SSI), Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Center for the Study of Cosmic Evolution (CSCE), Michigan State University [East Lansing], Michigan State University System-Michigan State University System, Department of Geography, Department of geography, Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris, Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
individual objects, 85A15, lines and bands -ISM, Astrophysics::High Energy Astrophysical Phenomena, Central object, FOS: Physical sciences, Astrophysics, 01 natural sciences, W33B, law.invention, Radio telescope, symbols.namesake, law, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Maser, masers -ISM, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, magnetic fields -ISM, Line (formation), [PHYS]Physics [physics], Physics, Zeeman effect, 010308 nuclear & particles physics, molecules -ISM, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Magnetic field, Wavelength, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), symbols, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Excitation
Abstract

The active star-forming region W33B is a source of OH and H2O maser emission located in distinct zones around the central object. The aim was to obtain the complete Stokes pattern of polarised OH maser emission, to trace its variability and to investigate flares and long-term variability of the H2O maser and evolution of individual emission features. Observations in the OH lines at a wavelength of 18 cm were carried out on the Nan\c{c}ay radio telescope (France) at a number of epochs in 2008--2014; H2O line observations (long-term monitoring) at a wavelength of 1.35 cm were performed on the 22-metre radio telescope of the Pushchino Radio Astronomy Observatory (Russia) between 1981 and 2014. We have observed strong variability of the emission features in the main 1665- and 1667-MHz OH lines as well as in the 1612-MHz satellite line. Zeeman splitting has been detected in the 1665-MHz OH line at 62 km/s and in the 1667-MHz line at 62 and 64 km/s. The magnetic field intensity was estimated to be from 2 to 3 mG. The H2O emission features form filaments, chains with radial-velocity gradients, or more complicated structures including large-scale ones. Long-term observations of the hydroxyl maser in the W33B region have revealed narrowband polarised emission in the 1612-MHz line with a double-peak profile characteristic of Type IIb circumstellar masers. The 30-year monitoring of the water-vapour maser in W33B showed several strong flares of the H2O line. The observed radial-velocity drift of the H2O emission features suggests propagation of an excitation wave in the masering medium with a gradient of radial velocities. In OH and H2O masers some turbulent motions of material are inferred., Comment: 18 pages, 12 figures

Published
2015

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