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VLA Detection of the Exciting Sources of the Molecular Outflows Associated with L1448 IRS2, IRAS 05327+3404, L43, IRAS 22142+5206, L1211, and IRAS 23545+6508  [cached]
G. Anglada,Luis F. Rodru00EDguez
Revista mexicana de astronomía y astrofísica , 2002,
Abstract: Presentamos observaciones sensitivas hechas con el Very Large Array" a 3.6 cm hacia nueve campos conteniendo flujos moleculares. Detectamos candidatos para las fuentes excitadoras de flujos moleculares en seis de los campos: L1448 IRS2, IRAS 05327+3404, L43, IRAS 22142+5206, L1211, e IRAS 23545+6508. Discutimos los parámetros de estas fuentes, así como su relación con fuentes detectadas a otras longitudes de onda.
Infrared and Millimetric Study of the Young Outflow Cepheus E  [PDF]
A. Moro-Martin,A. Noriega-Crespo,S. Molinari,L. Testi,J. Cernicharo,A. Sargent
Physics , 2001, DOI: 10.1086/321443
Abstract: The Cepheus E outflow has been studied in the mid and far infrared using the ISO CAM and LWS instruments, and at millimetric wavelengths using OVRO. In the near and mid-IR, its morphology is similar to that expected for a jet driven outflow, where the leading bow shocks entrain and accelerate the surrounding molecular gas. As expected, fine structure atomic/ionic emission lines arise from the bow shocks, at both the Mach Disk and the stagnation tip, where J-shocks are dominant. The H2, H2O and CO molecular emission could arise further `downstream' at the bow shock wings where the shocks (v = 8-35 km/s) are oblique and more likely to be C-type. The 13CO emission arises from entrained molecular gas and a compact high velocity emission is observed, together with an extended low velocity component that almost coincides spatially with the H2 near-IR emission. The millimetric continuum emission shows two sources. We identify one of them with IRAS 23011+6126, postulating is the driver of the Cepheus E outflow; the other, also an embedded source, is likely to be driving one of other outflows observed in the region.
Far Infrared Study of IRAS 00494+5617 & IRAS 05327-0457  [PDF]
B. Mookerjea,S. K. Ghosh,T. N. Rengarajan,S. N. Tandon,R. P. Verma
Physics , 2000, DOI: 10.1086/309255
Abstract: High angular resolution far-infrared observations at 143 & 185 \micron, using the TIFR 1-m balloon borne telescope, are presented for two Galactic star forming complexes associated with IRAS 00494+5617 and 05327-0457. The latter map also reveals the cold dust in OMC-3. The HIRES processed IRAS maps at 12, 25, 60 & 100 micron have also been presented for comparison. Both these regions are illuminated at the edges by high mass stars with substantial UV flux.The present study is aimed at quantifying the role of the nearby stars vis-a-vis embedded young stellar objects in the overall heating of these sources. Based on the FIR observations at 143 & 185 micron carried out simultaneously with almost identical angular resolution, reliable dust temperature and optical depth maps have been generated for the brighter regions of these sources. Radiative transfer modeling in spherical geometry has been carried out to extract physical parameters of these sources by considering the observational constraints like : spectral energy distribution, angular size at different wavelengths, dust temperature distribution etc. It has been concluded that for both IRAS 00494+5617 and IRAS 05327-0457, the embedded energy sources play the major role in heating them with finite contribution from the nearby stars. The best fit model for IRAS 00494+5617 is consistent with a simple two phase clump-interclump picture with $\sim$ 5% volume filling factor (of clumps) and a density contrast of $\approx$ 80.
Asteroid detection at millimetric wavelengths with the Planck survey  [PDF]
G. Cremonese,F. Marzari,C. Burigana,M. Maris
Physics , 2002, DOI: 10.1016/S1384-1076(02)00176-8
Abstract: The Planck mission, originally devised for cosmological studies, offers the opportunity to observe Solar System objects at millimetric and submillimetric wavelengths. We concentrate in this paper on the asteroids of the Main Belt. We intend to estimate the number of asteroids that can can be detected during the mission and to evaluate the strength of their signal. We have rescaled the instrument sensitivities, calculated by the LFI and HFI teams for sources fixed in the sky, introducing some degradation factors to properly account for moving objects. In this way a detection threshold is derived for asteroidal detection that is related to the diameter of the asteroid and its geocentric distance. We have developed a numerical code that models the detection of asteroids in the LFI and HFI channels during the mission. This code perfoprms a detailed integration of the orbits of the asteroids in the timespan of the mission and identifies those bodies that fall in the beams of Planck and their signal stenght. According to our simulations, a total of 397 objects will be observed by Planck and an asteroidal body will be detected in some beam in 30% of the total sky scan--circles. A significant fraction (in the range from ~50 to 100 objects) of the 397 asteroids will be observed with a high S/N ratio. Flux measurements of a large sample of asteroids in the submillimeter and millimeter range are relevant since they allow to analyze the thermal emission and its relation to the surface and regolith properties. Furthermore, it will be possible to check on a wider base the two standard thermal models, based on a nonrotating or rapidly rotating sphere. Our method can also be used to separate Solar System sources from cosmological sources in the survey. This work is based on Planck LFI activities.
The Diabolo photometer and the future of ground-based millimetric bolometer devices  [PDF]
F. -X. Desert,A. Benoit,Ph. Camus,M. Giard,E. Pointecouteau,N. Aghanim,J. -Ph. Bernard,N. Coron,J. -M. Lamarre,Ph. Marty,J. Delabrouille,V. Soglasnova
Physics , 2001, DOI: 10.1063/1.1475613
Abstract: The millimetric atmospheric windows at 1 and 2 mm are interesting targets for cosmological studies. Two broad areas appear leading this field: 1) the search for high redshift star-forming galaxies and 2) the measurement of Sunyaev-Zel'dovich (SZ) effect in clusters of galaxies at all redshifts. The Diabolo photometer is a dual-channel photometer working at 1.2 and 2.1 mm and dedicated to high angular resolution measurements of the Sunyaev--Zel'dovich effect towards distant clusters. It uses 2 by 3 bolometers cooled down to 0.1 K with a compact open dilution cryostat. The high resolution is provided by the IRAM 30 m telescope. The result of several Winter campaigns are reported here, including the first millimetric map of the SZ effect that was obtained by Pointecouteau et al. (2001) on RXJ1347-1145, the non-detection of a millimetric counterpart to the radio decrement towards PC1643+4631 and 2 mm number count upper limits. We discuss limitations in ground-based single-dish millimetre observations, namely sky noise and the number of detectors. We advocate the use of fully sampled arrays of (100 to 1000) bolometers as a big step forward in the millimetre continuum science. Efforts in France are briefly mentionned.
Millimetric Astronomy from the High Antarctic Plateau: site testing at Dome C  [PDF]
L. Valenziano,G. Dall'Oglio
Physics , 1999, DOI: 10.1071/AS99167
Abstract: Preliminary site testing at Dome C (Antarctica) is presented, using both Automatic Weather Station (AWS) meteorological data (1986-1993) and Precipitable Water Vapor (PWV) measurements made by the authors. A comparison with South Pole and other sites is made. The South Pole is a well established astrophysical observing site, where extremely good conditions are reported for a large fraction of time during the year. Dome C, where Italy and France are building a new scientific station, is a potential observing site in the millimetric and sub-millimetric range. AWS are operating at both sites and they have been continuously monitoring temperature, pressure, wind speed and direction for more than ten years. Site testing instruments are already operating at the South Pole (AASTO, Automated Astrophysical Site-Testing Observatory), while ''light'' experiments have been running at Dome C (APACHE, Antarctic Plateau Anisotropy CHasing Experiment) during summertime. A direct comparison between the two sites is planned in the near future, using the AASTO. The present analysis shows that the average wind speed is lower at Dome C (~1 m/s) than at the South Pole (~2 m/s), while temperature and PWV are comparable.
Scalar-tensor propagation of light in the inner solar system at the millimetric level  [PDF]
Olivier Minazzoli,Bertrand Chauvineau
Physics , 2010, DOI: 10.1088/0264-9381/28/8/085010
Abstract: In a recent paper [1], motivated by forthcoming space experiments involving propagation of light in the Solar System, we have proposed an extention of the IAU metric equations at the c-4 level in General Relativity. However, scalar-tensor theories may induce corrections numerically comparable to the c-4 general relativistic terms. Accordingly, one first proposes in this paper an extension of [1] to the scalar-tensor case. The case of a hierarchized system (such as the Solar system) is emphasized. In this case, the relevant metric solution is proposed. Then, the geodesic solution relevant for propagation of light in the inner solar system at the millimetric level is given in explicit form.
A search for millimetric emission from Gamma Ray Bursts  [PDF]
S. Ali,R. K. Schaefer,M. Limon,L. Piccirillo
Physics , 1997, DOI: 10.1086/304579
Abstract: We have used the 2- year Differential Microwave Radiometer data from the COsmic Background Explorer (COBE) satellite to systematically search for millimetric (31 - 90 GHz) emission from the Gamma Ray Bursts (GRBs) in the Burst And Transient Source Experiment (BATSE) GRB 3B catalog. The large beamsize of the COBE instrument (7 degs FWHM) allows for an efficient search of the large GRB positional error boxes, although it also means that fluxes from (point source) GRB objects will be somewhat diluted. A likelihood analysis has been used to look for a change in the level of millimetric emission from the locations of 81 GRB events during the first two years (1990 & 1991) of the COBE mission. The likelihood analysis determined that we did not find any significant millimetric signal before or after the occurance of the GRB. We find 95% confidence level upper limits of 175, 192 and 645 Jy or, in terms of fluxes, of 9.6, 16.3 and 54.8 10^{-13} erg/cm^2/s, respectively at 31, 53 and 90 GHz. We also look separately at different classes of GRBs, including a study of the top ten (in peak flux) GRBs, the "short burst" and "long burst" subsets, finding similar upper limits. While these limits may be somewhat higher than one would like, we estimate that using this technique with future planned missions could push these limits down to \sim 1 mJy.
Intensity and polarization of the atmospheric emission at millimetric wavelengths at Dome Concordia  [PDF]
E. S. Battistelli,G. Amico,A. Baù,L. Bergé,é. Bréelle,R. Charlassier,S. Collin,A. Cruciani,P. de Bernardis,C. Dufour,L. Dumoulin,M. Gervasi,M. Giard,C. Giordano,Y. Giraud-Héraud,L. Guglielmi,J. -C. Hamilton,J. Landé,B. Maffei,M. Maiello,S. Marnieros,S. Masi,A. Passerini,F. Piacentini,M. Piat,L. Piccirillo,G. Pisano,G. Polenta,C. Rosset,M. Salatino,A. Schillaci,R. Sordini,S. Spinelli,A. Tartari,M. Zannoni
Physics , 2012, DOI: 10.1111/j.1365-2966.2012.20951.x
Abstract: Atmospheric emission is a dominant source of disturbance in ground-based astronomy at mm wavelengths. The Antarctic plateau is recognized to be an ideal site for mm and sub-mm observations, and the French/Italian base of Dome C is among the best sites on Earth for these observations. In this paper we present measurements, performed using the BRAIN-pathfinder experiment, at Dome C of the atmospheric emission in intensity and polarization at 150GHz, one of the best observational frequencies for CMB observations when considering cosmic signal intensity, atmospheric transmission, detectors sensitivity, and foreground removal. Careful characterization of the air-mass synchronous emission has been performed, acquiring more that 380 elevation scans (i.e. "skydip") during the third BRAIN-pathfinder summer campaign in December 2009/January 2010. The extremely high transparency of the Antarctic atmosphere over Dome Concordia is proven by the very low measured optical depth: =0.050 \pm 0.003 \pm 0.011 where the first error is statistical and the second is systematic error. Mid term stability, over the summer campaign, of the atmosphere emission has also been studied. Adapting the radiative transfer atmosphere emission model "am" to the particular conditions found at Dome C, we also infer the level of the PWV content of the atmosphere, notoriously the main source of disturbance in millimetric astronomy (=0.77 +/- 0.06 + 0.15 - 0.12 mm). Upper limits on the air-mass correlated polarized signal are also placed for the first time. The degree of circular polarization of atmospheric emission is found to be lower than 0.2% (95%CL), while the degree of linear polarization is found to be lower than 0.1% (95%CL). These limits include signal-correlated instrumental spurious polarization.
Detection of millimetric deformation using a terrestrial laser scanner: experiment and application to a rockfall event  [PDF]
A. Abellán,M. Jaboyedoff,T. Oppikofer,J. M. Vilaplana
Natural Hazards and Earth System Sciences (NHESS) & Discussions (NHESSD) , 2009,
Abstract: Terrestrial laser scanning (TLS) is one of the most promising surveying techniques for rockslope characterization and monitoring. Landslide and rockfall movements can be detected by means of comparison of sequential scans. One of the most pressing challenges of natural hazards is combined temporal and spatial prediction of rockfall. An outdoor experiment was performed to ascertain whether the TLS instrumental error is small enough to enable detection of precursory displacements of millimetric magnitude. This consists of a known displacement of three objects relative to a stable surface. Results show that millimetric changes cannot be detected by the analysis of the unprocessed datasets. Displacement measurement are improved considerably by applying Nearest Neighbour (NN) averaging, which reduces the error (1σ) up to a factor of 6. This technique was applied to displacements prior to the April 2007 rockfall event at Castellfollit de la Roca, Spain. The maximum precursory displacement measured was 45 mm, approximately 2.5 times the standard deviation of the model comparison, hampering the distinction between actual displacement and instrumental error using conventional methodologies. Encouragingly, the precursory displacement was clearly detected by applying the NN averaging method. These results show that millimetric displacements prior to failure can be detected using TLS.
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