HERSCHEL PACS OBSERVATIONS AND MODELING OF DEBRIS DISKS IN THE TUCANA-HOROLOGIUM ASSOCIATION

Energy Technology Data Exchange (ETDEWEB)

Donaldson, J. K. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Roberge, A. [Exoplanets and Stellar Astrophysics Laboratory, NASA Goddard Space Flight Center, Code 667, Greenbelt, MD 20771 (United States); Chen, C. H. [Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States); Augereau, J.-C.; Menard, F. [UJF - Grenoble 1/CNRS-INSU, Institut de Planetologie et d' Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble, F-38041 (France); Dent, W. R. F. [ALMA, Avda Apoquindo 3846, Piso 19, Edificio Alsacia, Las Condes, Santiago (Chile); Eiroa, C.; Meeus, G. [Dpt. Fisica Teorica, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Krivov, A. V. [Astrophysikalishes Institut, Friedrich-Schiller-Universitaet Jena, Schillergaesschen 2-3, 07745 Jena (Germany); Mathews, G. S. [Institute for Astronomy (IfA), University of Hawaii, 2680 Woodlawn Dr., Honolulu, HI 96822 (United States); Riviere-Marichalar, P. [Centro de Astrobiologia Depto. Astrofisica (CSIC-INTA), POB 78, 28691 Villanueva de la Canada (Spain); Sandell, G., E-mail: jessd@astro.umd.edu [SOFIA-USRA, NASA Ames Research Center, Building N232, Rm. 146, Moffett Field, CA 94035 (United States)

2012-07-10

We present Herschel PACS photometry of 17 B- to M-type stars in the 30 Myr old Tucana-Horologium Association. This work is part of the Herschel Open Time Key Programme 'Gas in Protoplanetary Systems'. 6 of the 17 targets were found to have infrared excesses significantly greater than the expected stellar IR fluxes, including a previously unknown disk around HD30051. These six debris disks were fitted with single-temperature blackbody models to estimate the temperatures and abundances of the dust in the systems. For the five stars that show excess emission in the Herschel PACS photometry and also have Spitzer IRS spectra, we fit the data with models of optically thin debris disks with realistic grain properties in order to better estimate the disk parameters. The model is determined by a set of six parameters: surface density index, grain size distribution index, minimum and maximum grain sizes, and the inner and outer radii of the disk. The best-fitting parameters give us constraints on the geometry of the dust in these systems, as well as lower limits to the total dust masses. The HD105 disk was further constrained by fitting marginally resolved PACS 70 {mu}m imaging.

Origin of warm and hot gas emission from low-mass protostars: Herschel-HIFI observations of CO J = 16-15

DEFF Research Database (Denmark)

Kristensen, Lars Egstrøm; Van Dishoeck, E. F.; Mottram, J. C.

2017-01-01

Context. Through spectrally unresolved observations of high-J CO transitions, Herschel Photodetector Array Camera and Spectrometer (PACS) has revealed large reservoirs of warm (300 K) and hot (700 K) molecular gas around low-mass protostars. The excitation and physical origin of this gas is still...... in cooling molecular H2-poor gas just prior to the onset of H2 formation. High spectral resolution observations of highly excited CO transitions uniquely shed light on the origin of warm and hot gas in low-mass protostellar objects....... not understood. Aims. We aim to shed light on the excitation and origin of the CO ladder observed toward protostars, and on the water abundance in different physical components within protostellar systems using spectrally resolved Herschel-HIFI data. Methods. Observations are presented of the highly excited CO...

Warm gas towards young stellar objects in Corona Australis. Herschel/PACS observations from the DIGIT key programme

Science.gov (United States)

Lindberg, Johan E.; Jørgensen, Jes K.; Green, Joel D.; Herczeg, Gregory J.; Dionatos, Odysseas; Evans, Neal J.; Karska, Agata; Wampfler, Susanne F.

2014-05-01

Context. The effects of external irradiation on the chemistry and physics in the protostellar envelope around low-mass young stellar objects are poorly understood. The Corona Australis star-forming region contains the R CrA dark cloud, comprising several low-mass protostellar cores irradiated by an intermediate-mass young star. Aims: We study the effects of the irradiation coming from the young luminous Herbig Be star R CrA on the warm gas and dust in a group of low-mass young stellar objects. Methods: Herschel/PACS far-infrared datacubes of two low-mass star-forming regions in the R CrA dark cloud are presented. The distributions of CO, OH, H2O, [C ii], [O i], and continuum emission are investigated. We have developed a deconvolution algorithm which we use to deconvolve the maps, separating the point-source emission from the extended emission. We also construct rotational diagrams of the molecular species. Results: By deconvolution of the Herschel data, we find large-scale (several thousand AU) dust continuum and spectral line emission not associated with the point sources. Similar rotational temperatures are found for the warm CO (282 ± 4 K), hot CO (890 ± 84 K), OH (79 ± 4 K), and H2O (197 ± 7 K) emission in the point sources and the extended emission. The rotational temperatures are also similar to those found in other more isolated cores. The extended dust continuum emission is found in two ridges similar in extent and temperature to molecular millimetre emission, indicative of external heating from the Herbig Be star R CrA. Conclusions: Our results show that nearby luminous stars do not increase the molecular excitation temperatures of the warm gas around young stellar objects (YSOs). However, the emission from photodissociation products of H2O, such as OH and O, is enhanced in the warm gas associated with these protostars and their surroundings compared to similar objects not subjected to external irradiation. Table 9 and appendices are available in

Champagne flutes and brandy snifters: modelling protostellar outflow-cloud chemical interfaces

Science.gov (United States)

Rollins, R. P.; Rawlings, J. M. C.; Williams, D. A.; Redman, M. P.

2014-10-01

A rich variety of molecular species has now been observed towards hot cores in star-forming regions and in the interstellar medium. An increasing body of evidence from millimetre interferometers suggests that many of these form at the interfaces between protostellar outflows and their natal molecular clouds. However, current models have remained unable to explain the origin of the observational bias towards wide-angled `brandy snifter' shaped outflows over narrower `champagne flute' shapes in carbon monoxide imaging. Furthermore, these wide-angled systems exhibit unusually high abundances of the molecular ion HCO+. We present results from a chemodynamic model of such regions where a rich chemistry arises naturally as a result of turbulent mixing between cold, dense molecular gas and the hot, ionized outflow material. The injecta drives a rich and rapid ion-neutral chemistry in qualitative and quantitative agreement with the observations. The observational bias towards wide-angled outflows is explained naturally by the geometry-dependent ion injection rate causing rapid dissociation of CO in the younger systems.

THE EXTRAORDINARY FAR-INFRARED VARIATION OF A PROTOSTAR: HERSCHEL/PACS OBSERVATIONS OF LRLL54361

Energy Technology Data Exchange (ETDEWEB)

Balog, Zoltan; Detre, Örs H.; Bouwmann, Jeroen; Nielbock, Markus; Klaas, Ulrich; Krause, Oliver; Henning, Thomas [Max Planck Institute for Astronomy Königstuhl 17, Heidelberg D-69117 (Germany); Muzerolle, James [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Flaherty, Kevin [Astronomy Department, Wesleyan University, Middletown, CT 06459 (United States); Furlan, Elise [Natinal Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States); Gutermuth, Rob [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Juhasz, Attila [Leiden Observatory, Leiden University, Niels Bohrweg 2, NL-2333-CA Leiden (Netherlands); Bally, John [CASA, University of Colorado, CB 389, Boulder, CO 80309 (United States); Marton, Gabor, E-mail: balog@mpia.de [Konkoly Observatory, Research Center for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Konkoly Thege 15-17, 1121 Budapest (Hungary)

2014-07-10

We report Herschel/Photodetector Array Camera and Spectrometer (PACS) photometric observations at 70 μm and 160 μm of LRLL54361—a suspected binary protostar that exhibits periodic (P = 25.34 days) flux variations at shorter wavelengths (3.6 μm and 4.5 μm) thought to be due to pulsed accretion caused by binary motion. The PACS observations show unprecedented flux variation at these far-infrared wavelengths that are well correlated with the variations at shorter wavelengths. At 70 μm the object increases its flux by a factor of six while at 160 μm the change is about a factor of two, consistent with the wavelength dependence seen in the far-infrared spectra. The source is marginally resolved at 70 μm with varying FWHM. Deconvolved images of the sources show elongations exactly matching the outflow cavities traced by the scattered light observations. The spatial variations are anti-correlated with the flux variation, indicating that a light echo is responsible for the changes in FWHM. The observed far-infrared flux variability indicates that the disk and envelope of this source is periodically heated by the accretion pulses of the central source, and suggests that such long wavelength variability in general may provide a reasonable proxy for accretion variations in protostars.

The chemical structure of the Class 0 protostellar envelope NGC 1333 IRAS 4A⋆⋆

Science.gov (United States)

Koumpia, E.; Semenov, D. A.; van der Tak, F. F. S.; Boogert, A. C. A.; Caux, E.

2017-07-01

Context. It is not well known what drives the chemistry of a protostellar envelope, in particular the role of the stellar mass and the protostellar outflows on the chemical enrichment of such environments. Aims: We study the chemical structure of the Class 0 protostellar envelope NGC 1333 IRAS 4A in order to (I) investigate the influence of the outflows on the chemistry; (II) constrain the age of our studied object; (III) compare it with a typical high-mass protostellar envelope. Methods: In our analysis we use JCMT line mapping (360-373 GHz) and HIFI pointed spectra (626.01-721.48 GHz). To study the influence of the outflow on the degree of deuteration, we compare JCMT maps of HCO+ and DCO+ with non-LTE (RADEX) models in a region that spatially covers the outflow activity of IRAS 4A. To study the envelope chemistry, we derive empirical molecular abundance profiles for the observed species using the Monte Carlo radiative transfer code (RATRAN) and adopting a 1D dust density/temperature profile from the literature. We use a combination of constant abundance profiles and abundance profiles that include jumps at two radii (T 100 K or T 30 K) to fit our observations. We compare our best-fit observed abundance profiles with the predictions from the time dependent gas grain chemical code (ALCHEMIC). Results: We detect CO, 13CO, C18O, CS, HCN, HCO+, N2H+, H2CO, CH3OH, H2O, H2S, DCO+, HDCO, D2CO, SO, SO2, SiO, HNC, CN, C2H and OCS. We divide the detected lines in three groups based on their line profiles: a) broad emission (FWHM = 4-11 km s-1), b) narrow emission (FWHMtime-dependent gas-grain chemical model for the outer envelope, with the exceptions of HCN, HNC, CN. These species along with the CO abundance require an enhanced UV field which points towards an outflow cavity. The abundances with respect to H2 are 1 to 2 orders of magnitude lower than those observed in the high mass protostellar envelope (AFGL 2591), while they are found to be similar within factors of a

THE HERSCHEL AND IRAM CHESS SPECTRAL SURVEYS OF THE PROTOSTELLAR SHOCK L1157-B1: FOSSIL DEUTERATION

International Nuclear Information System (INIS)

Codella, C.; Fontani, F.; Vasta, M.; Ceccarelli, C.; Lefloch, B.; Kahane, C.; Taquet, V.; Wiesenfeld, L.; Busquet, G.; Caselli, P.; Lis, D.; Viti, S.

2012-01-01

We present the first study of deuteration toward the protostellar shock L1157-B1, based on spectral surveys performed with the Herschel-HIFI and IRAM 30 m telescopes. The L1157 outflow is driven by a low-mass Class 0 protostar and is considered the prototype of the so-called chemically active outflows. The young (2000 yr), bright blueshifted bow shock, B1, is an ideal laboratory for studying the gas chemically enriched by the release of dust mantles due to the passage of a shock. A total of 12 emission lines (up to E u = 63 K) of CH 2 DOH, HDCO, and DCN are detected. In addition, two lines of NH 2 D and HDO are tentatively reported. To estimate the deuteration, we also extracted from our spectral survey emission lines of non-deuterated isotopologues ( 13 CH 3 OH, H 2 13 CO, H 13 CN, H 2 13 CO, and NH 3 ). We infer higher deuteration fractions for CH 3 OH (D/H = 0.2-2 × 10 –2 ) and H 2 CO (5-8 × 10 –3 ) than for H 2 O (0.4-2 × 10 –3 ), HCN (∼10 –3 ), and ammonia (≤3 × 10 –2 ). The measurement of deuteration of water, formaldehyde, and methanol in L1157-B1 provides a fossil record of the gas before it was shocked by the jet driven by the protostar. A comparison with gas-grain models indicates that the gas passed through a low-density (≤10 3 cm –3 ) phase, during which the bulk of water ices formed, followed by a phase of increasing density, up to 3 × 10 4 cm –3 , during which formaldehyde and methanol ices formed.

EMBEDDED PROTOSTARS IN THE DUST, ICE, AND GAS IN TIME (DIGIT) HERSCHEL KEY PROGRAM: CONTINUUM SEDs, AND AN INVENTORY OF CHARACTERISTIC FAR-INFRARED LINES FROM PACS SPECTROSCOPY

Energy Technology Data Exchange (ETDEWEB)

Green, Joel D.; Evans, Neal J. II; Rascati, Michelle R. [Department of Astronomy, University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712-1205 (United States); Jorgensen, Jes K.; Dionatos, Odysseas; Lindberg, Johan E. [Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark); Herczeg, Gregory J. [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Kristensen, Lars E.; Yildiz, Umut A.; Van Kempen, Tim A. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300-RA Leiden (Netherlands); Lee, Jeong-Eun [Department of Astronomy and Space Science, Kyung Hee University, Gyeonggi 446-701 (Korea, Republic of); Salyk, Colette [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Meeus, Gwendolyn [Dpt. Fisica Teorica, Universidad Autonoma de Madrid, Campus Cantoblanco, E-28049 Madrid (Spain); Bouwman, Jeroen [Max Planck Institute for Astronomy, D-69117 Heidelberg (Germany); Visser, Ruud; Bergin, Edwin A. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109-1042 (United States); Van Dishoeck, Ewine F.; Karska, Agata; Fedele, Davide [Max-Planck Institute for Extraterrestrial Physics, Postfach 1312, D-85741 Garching (Germany); Dunham, Michael M., E-mail: joel@astro.as.utexas.edu [Department of Astronomy, Yale University, New Haven, CT 06511 (United States); Collaboration: DIGIT Team1

2013-06-20

We present 50-210 {mu}m spectral scans of 30 Class 0/I protostellar sources, obtained with Herschel-PACS, and 0.5-1000 {mu}m spectral energy distributions, as part of the Dust, Ice, and Gas in Time Key Program. Some sources exhibit up to 75 H{sub 2}O lines ranging in excitation energy from 100 to 2000 K, 12 transitions of OH, and CO rotational lines ranging from J = 14 {yields} 13 up to J = 40 {yields} 39. [O I] is detected in all but one source in the entire sample; among the sources with detectable [O I] are two very low luminosity objects. The mean 63/145 {mu}m [O I] flux ratio is 17.2 {+-} 9.2. The [O I] 63 {mu}m line correlates with L{sub bol}, but not with the time-averaged outflow rate derived from low-J CO maps. [C II] emission is in general not local to the source. The sample L{sub bol} increased by 1.25 (1.06) and T{sub bol} decreased to 0.96 (0.96) of mean (median) values with the inclusion of the Herschel data. Most CO rotational diagrams are characterized by two optically thin components ( = (0.70 {+-} 1.12) x 10{sup 49} total particles). N{sub CO} correlates strongly with L{sub bol}, but neither T{sub rot} nor N{sub CO}(warm)/N{sub CO}(hot) correlates with L{sub bol}, suggesting that the total excited gas is related to the current source luminosity, but that the excitation is primarily determined by the physics of the interaction (e.g., UV-heating/shocks). Rotational temperatures for H{sub 2}O ( = 194 +/- 85 K) and OH ( = 183 +/- 117 K) are generally lower than for CO, and much of the scatter in the observations about the best fit is attributed to differences in excitation conditions and optical depths among the detected lines.

TNOs are Cool: Thermophysical modeling of a sample of 20 classical KBOs using Herschel/PACS

NARCIS (Netherlands)

Vilenius, E.; Müller, T.; Pal, A.; Santos-Sanz, P.; Rengel, M.; Hartogh, P.; Protopapa, S.; Mueller, M.; Mommert, M.; Stansberry, J.; Lellouch, E.; Böhnhardt, H.; Ortiz, J. L.; Thirouin, A.; Henry, F.; Delsanti, A.; Fornasier, S.; Hestroffer, D.; Dotto, E.

2011-01-01

We determine the sizes and albedos of 20 classical Kuiper belt objects. Our observations with the PACS instrument on-board Herschel Space Observatory cover the wavelength range where the thermal emission from trans-Neptunian objects has its maximum. We use a consistent method for data reduction and

Turbulent mixing layers in supersonic protostellar outflows, with application to DG Tauri

Science.gov (United States)

White, M. C.; Bicknell, G. V.; Sutherland, R. S.; Salmeron, R.; McGregor, P. J.

2016-01-01

Turbulent entrainment processes may play an important role in the outflows from young stellar objects at all stages of their evolution. In particular, lateral entrainment of ambient material by high-velocity, well-collimated protostellar jets may be the cause of the multiple emission-line velocity components observed in the microjet-scale outflows driven by classical T Tauri stars. Intermediate-velocity outflow components may be emitted by a turbulent, shock-excited mixing layer along the boundaries of the jet. We present a formalism for describing such a mixing layer based on Reynolds decomposition of quantities measuring fundamental properties of the gas. In this model, the molecular wind from large disc radii provides a continual supply of material for entrainment. We calculate the total stress profile in the mixing layer, which allows us to estimate the dissipation of turbulent energy, and hence the luminosity of the layer. We utilize MAPPINGS IV shock models to determine the fraction of total emission that occurs in [Fe II] 1.644 μm line emission in order to facilitate comparison to previous observations of the young stellar object DG Tauri. Our model accurately estimates the luminosity and changes in mass outflow rate of the intermediate-velocity component of the DG Tau approaching outflow. Therefore, we propose that this component represents a turbulent mixing layer surrounding the well-collimated jet in this object. Finally, we compare and contrast our model to previous work in the field.

Study of Outflow and Molecular Lines from the Observations of BHR71 by The Herschel Key Program,``Dust, Ice, and Gas In Time" (DIGIT)

Science.gov (United States)

Yang, Yao-Lun; Green, Joel D.

2014-07-01

The infall and outflow processes initiated by the collapse a dense core are widely observed in Class 0 protostars, and significantly change the density and temperature structure of the prestellar core as well as the following disk and envelope evolution. Since the Class 0 protostars are usually embedded in the cold molecular envelope preventing them from being observed at visible or near-IR wavelengths, the spectral analyses of the far-IR spectra provide us a window to look through the envelope and constrain the physical properties of the envelope and the core. BHR71, a Class 0 embedded protostar, is located in an isolated neighborhood with a collimated bipolar outflow and shows a rich far-IR spectrum as observed in the DIGIT program (PI: Neal Evans) with Herschel. It has numerous molecular and atomic features that can constrain its physical properties and the density structure well. In this research, we developed a robust data reduction (Green et al. 2013a, b) and automatic line fitting package that ensures all of the molecular and atomic lines are extracted to the same standard and it can be easily used for any other protostars observed by Herschel as well. We found 44 and 28 emission lines in the central spaxel in the PACS and the SPIRE bands respectively, including CO, 13CO, OH, and H2O. The extended feature observed at low-J CO and several H2O lines are consistent to the outflow direction but less collimated and a heterogeneous environment is concluded from the rotational diagram analysis. A dust Monte Carlo radiative transfer simulation using RADMC-3D will reveal the embedded structure with a dust density profile of a flared disk and a spherical envelope with bipolar outflow cavity. We will use a line radiative transfer simulation for multiple species to constrain the chemical abundance distributions and their temperature profiles.With high sensitivity spatial resolved spectra and simulated internal structure analysis of BHR71 will provide a good test of

THE HERSCHEL AND IRAM CHESS SPECTRAL SURVEYS OF THE PROTOSTELLAR SHOCK L1157-B1: FOSSIL DEUTERATION

Energy Technology Data Exchange (ETDEWEB)

Codella, C.; Fontani, F.; Vasta, M. [INAF, Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, I-50125 Firenze (Italy); Ceccarelli, C.; Lefloch, B.; Kahane, C.; Taquet, V.; Wiesenfeld, L. [UJF-Grenoble 1/CNRS-INSU, Institut de Planetologie et d' Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble, F-38041 (France); Busquet, G. [INAF - Istituto di Astrofisica e Planetologia Spaziali, via Fosso del Cavaliere 100, I-00133, Roma (Italy); Caselli, P. [School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT (United Kingdom); Lis, D. [California Institute of Technology, Cahill Center for Astronomy and Astrophysics 301-17, Pasadena, CA 91125 (United States); Viti, S., E-mail: codella@rcetri.astro.it [Department of Physics and Astronomy, University College London, London (United Kingdom)

2012-09-20

We present the first study of deuteration toward the protostellar shock L1157-B1, based on spectral surveys performed with the Herschel-HIFI and IRAM 30 m telescopes. The L1157 outflow is driven by a low-mass Class 0 protostar and is considered the prototype of the so-called chemically active outflows. The young (2000 yr), bright blueshifted bow shock, B1, is an ideal laboratory for studying the gas chemically enriched by the release of dust mantles due to the passage of a shock. A total of 12 emission lines (up to E{sub u} = 63 K) of CH{sub 2}DOH, HDCO, and DCN are detected. In addition, two lines of NH{sub 2}D and HDO are tentatively reported. To estimate the deuteration, we also extracted from our spectral survey emission lines of non-deuterated isotopologues ({sup 13}CH{sub 3}OH, H{sub 2} {sup 13}CO, H{sup 13}CN, H{sub 2} {sup 13}CO, and NH{sub 3}). We infer higher deuteration fractions for CH{sub 3}OH (D/H = 0.2-2 Multiplication-Sign 10{sup -2}) and H{sub 2}CO (5-8 Multiplication-Sign 10{sup -3}) than for H{sub 2}O (0.4-2 Multiplication-Sign 10{sup -3}), HCN ({approx}10{sup -3}), and ammonia ({<=}3 Multiplication-Sign 10{sup -2}). The measurement of deuteration of water, formaldehyde, and methanol in L1157-B1 provides a fossil record of the gas before it was shocked by the jet driven by the protostar. A comparison with gas-grain models indicates that the gas passed through a low-density ({<=}10{sup 3} cm{sup -3}) phase, during which the bulk of water ices formed, followed by a phase of increasing density, up to 3 Multiplication-Sign 10{sup 4} cm{sup -3}, during which formaldehyde and methanol ices formed.

Formation and fragmentation of protostellar dense cores

International Nuclear Information System (INIS)

Maury, Anaelle

2009-01-01

Stars form in molecular clouds, when they collapse and fragment to produce protostellar dense cores. These dense cores are then likely to contract under their own gravity, and form young protostars, that further evolve while accreting their circumstellar mass, until they reach the main sequence. The main goal of this thesis was to study the formation and fragmentation of protostellar dense cores. To do so, two main studies, described in this manuscript, were carried out. First, we studied the formation of protostellar cores by quantifying the impact of protostellar outflows on clustered star formation. We carried out a study of the protostellar outflows powered by the young stellar objects currently formed in the NGc 2264-C proto-cluster, and we show that protostellar outflows seem to play a crucial role as turbulence progenitors in clustered star forming regions, although they seem unlikely to significantly modify the global infall processes at work on clump scales. Second, we investigated the formation of multiple systems by core fragmentation, by using high - resolution observations that allow to probe the multiplicity of young protostars on small scales. Our results suggest that the multiplicity rate of protostars on small scales increase while they evolve, and thus favor dynamical scenarios for the formation of multiple systems. Moreover, our results favor magnetized scenarios of core collapse to explain the small-scale properties of protostars at the earliest stages. (author) [fr

Fine structure of Galactic foreground ISM towards high-redshift AGN - utilizing Herschel PACS and SPIRE data

Science.gov (United States)

Perger, K.; Pinter, S.; Frey, S.; Tóth, L. V.

2018-05-01

One of the most certain ways to determine star formation rate in galaxies is based on far infrared (FIR) measurements. To decide the origin of the observed FIR emission, subtracting the Galactic foreground is a crucial step. We utilized Herschel photometric data to determine the hydrogen column densities in three galactic latitude regions, at b = 27°, 50° and -80°. We applied a pixel-by-pixel fit to the spectral energy distribution (SED) for the images aquired from parallel PACS-SPIRE observations in all three sky areas. We determined the column densities with resolutions 45'' and 6', and compared the results with values estimated from the IRAS dust maps. Column densities at 27° and 50° galactic latitudes determined from the Herschel data are in a good agreement with the literature values. However, at the highest galactic latitude we found that the column densities from the Herschel data exceed those derived from the IRAS dust map.

Recent achievements on the development of the HERSCHEL/PACS bolometer arrays

International Nuclear Information System (INIS)

Billot, N.; Agnese, P.; Boulade, O.; Cigna, C.; Doumayrou, E.; Horeau, B.; Lepennec, J.; Martignac, J.; Pornin, J.-L.; Reveret, V.; Rodriguez, L.; Sauvage, M.; Simoens, F.; Vigroux, L.

2006-01-01

A new type of bolometer arrays sensitive in the far Infrared and Submillimeter range has been developed and manufactured by CEA/LETI/SLIR since 1997. These arrays will be integrated in the PACS instrument (Photodetector Array Camera and Spectrometer) of ESA's Herschel Space Observatory (launch date 2007). The main innovations of CEA bolometers are their collective manufacturing technique (production of 3-side buttable 16x16 arrays) and their high mapping efficiency (large format detector and instantaneous Nyquist sampling). The measured NEP is 2.10 -16 W/Hz and the thermometric passband about 4-5Hz. In this article we describe CEA bolometers and present the results obtained during the last test campaign

Recent achievements on the development of the HERSCHEL/PACS bolometer arrays

Energy Technology Data Exchange (ETDEWEB)

Billot, N. [CEA/Saclay/SAp, UMR CEA/CNRS/UP7 Laboratoire AIM, Bat. 709, l' Orme des merisiers, 91191 Gif-sur-Yvette (France)]. E-mail: nbillot@cea.fr; Agnese, P. [CEA/LETI Grenoble, 17 Avenue des Martyrs, 38054 Grenoble (France); Boulade, O. [CEA/Saclay/SAp, UMR CEA/CNRS/UP7 Laboratoire AIM, Bat. 709, l' Orme des merisiers, 91191 Gif-sur-Yvette (France); Cigna, C. [CEA/LETI Grenoble, 17 Avenue des Martyrs, 38054 Grenoble (France); Doumayrou, E. [CEA/Saclay/SAp, UMR CEA/CNRS/UP7 Laboratoire AIM, Bat. 709, l' Orme des merisiers, 91191 Gif-sur-Yvette (France); Horeau, B. [CEA/Saclay/SAp, UMR CEA/CNRS/UP7 Laboratoire AIM, Bat. 709, l' Orme des merisiers, 91191 Gif-sur-Yvette (France); Lepennec, J. [CEA/Saclay/SAp, UMR CEA/CNRS/UP7 Laboratoire AIM, Bat. 709, l' Orme des merisiers, 91191 Gif-sur-Yvette (France); Martignac, J. [CEA/Saclay/SAp, UMR CEA/CNRS/UP7 Laboratoire AIM, Bat. 709, l' Orme des merisiers, 91191 Gif-sur-Yvette (France); Pornin, J.-L. [CEA/LETI Grenoble, 17 Avenue des Martyrs, 38054 Grenoble (France); Reveret, V. [CEA/Saclay/SAp, UMR CEA/CNRS/UP7 Laboratoire AIM, Bat. 709, l' Orme des merisiers, 91191 Gif-sur-Yvette (France); Rodriguez, L. [CEA/Saclay/SAp, UMR CEA/CNRS/UP7 Laboratoire AIM, Bat. 709, l' Orme des merisiers, 91191 Gif-sur-Yvette (France); Sauvage, M. [CEA/Saclay/SAp, UMR CEA/CNRS/UP7 Laboratoire AIM, Bat. 709, l' Orme des merisiers, 91191 Gif-sur-Yvette (France); Simoens, F. [CEA/LETI Grenoble, 17 Avenue des Martyrs, 38054 Grenoble (France); Vigroux, L. [CEA/Saclay/SAp, UMR CEA/CNRS/UP7 Laboratoire AIM, Bat. 709, l' Orme des merisiers, 91191 Gif-sur-Yvette (France); Institut d' Astrophysique de Paris, 75014 Paris (France)

2006-11-01

A new type of bolometer arrays sensitive in the far Infrared and Submillimeter range has been developed and manufactured by CEA/LETI/SLIR since 1997. These arrays will be integrated in the PACS instrument (Photodetector Array Camera and Spectrometer) of ESA's Herschel Space Observatory (launch date 2007). The main innovations of CEA bolometers are their collective manufacturing technique (production of 3-side buttable 16x16 arrays) and their high mapping efficiency (large format detector and instantaneous Nyquist sampling). The measured NEP is 2.10{sup -16}W/Hz and the thermometric passband about 4-5Hz. In this article we describe CEA bolometers and present the results obtained during the last test campaign.

ENVIRONMENT AND PROTOSTELLAR EVOLUTION

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yichen [Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile); Tan, Jonathan C., E-mail: yczhang.astro@gmail.com [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States)

2015-04-01

Even today in our Galaxy, stars form from gas cores in a variety of environments, which may affect the properties of the resulting star and planetary systems. Here, we study the role of pressure, parameterized via ambient clump mass surface density, on protostellar evolution and appearance, focusing on low-mass Sun-like stars and considering a range of conditions from relatively low pressure filaments in Taurus, to intermediate pressures of cluster-forming clumps like the Orion Nebula Cluster, to very high pressures that may be found in the densest infrared dark clouds or in the Galactic center. We present unified analytic and numerical models for the collapse of prestellar cores, accretion disks, protostellar evolution, and bipolar outflows, coupled with radiative transfer calculations and a simple astrochemical model to predict CO gas-phase abundances. Prestellar cores in high-pressure environments are smaller and denser and thus collapse with higher accretion rates and efficiencies, resulting in higher luminosity protostars with more powerful outflows. The protostellar envelope is heated to warmer temperatures, affecting infrared morphologies (and thus classification) and astrochemical processes like CO depletion onto dust grain ice mantles (and thus CO morphologies). These results have general implications for star and planet formation, especially via their effect on astrochemical and dust grain evolution during infall to and through protostellar accretion disks.

The HIFI spectral survey of AFGL 2591 (CHESS). I. Highly excited linear rotor molecules in the high-mass protostellar envelope

Science.gov (United States)

van der Wiel, M. H. D.; Pagani, L.; van der Tak, F. F. S.; Kaźmierczak, M.; Ceccarelli, C.

2013-05-01

Context. Linear rotor molecules such as CO, HCO+ and HCN are important probes of star-forming gas. For these species, temperatures of ≲ 50 K are sufficient to produce emission lines that are observable from the ground at (sub)millimeter wavelengths. Molecular gas in the environment of massive protostellar objects, however, is known to reach temperatures of several hundred K. To probe this, space-based far-infrared observations are required. Aims: We aim to reveal the gas energetics in the circumstellar environment of the prototypical high-mass protostellar object AFGL 2591. Methods: Rotational spectral line signatures of CO species, HCO+, CS, HCN and HNC from a 490-1240 GHz survey with Herschel/HIFI, complemented by ground-based JCMT and IRAM 30 m spectra, cover transitions in the energy range (Eup/k) between 5 K and ~ 300 K. Selected frequency settings in the highest frequency HIFI bands (up to 1850 GHz) extend this range to 750 K for 12C16O. The resolved spectral line profiles are used to separate and study various kinematic components. Observed line intensities are compared with a numerical model that calculates excitation balance and radiative transfer based on spherical geometry. Results: The line profiles show two emission components, the widest and bluest of which is attributed to an approaching outflow and the other to the envelope. We find evidence for progressively more redshifted and wider line profiles from the envelope gas with increasing energy level. This trend is qualitatively explained by residual outflow contribution picked up in the systematically decreasing beam size. Integrated line intensities for each species decrease as Eup/k increases from ≲ 50 to ~700 K. The H2 density and temperature of the outflow gas are constrained to ~105-106 cm-3 and 60-200 K. In addition, we derive a temperature between 9 and 17 K and N(H2) ~ 3 × 1021 cm-2 for a known foreground cloud seen in absorption, and N(H2) ≲ 1019 cm-2 for a second foreground component

Water in star-forming regions with Herschel (WISH)

DEFF Research Database (Denmark)

E. Kristensen, L.; F. van Dishoeck, E.; A. Bergin, E.

2012-01-01

was observed in the ground-state transition at 557 GHz with HIFI on Herschel in 29 embedded Class 0 and I protostars. Complementary far-IR and sub-mm continuum data (including PACS data from our program) are used to constrain the spectral energy distribution of each source. H2O intensities are compared...... sources, increasing from 10^-3 at 10^-1 at >10 km/s. The H2O abundance in the outer envelope is low, ~10^-10. The different H2O profile components show a clear evolutionary trend: in the Class 0 sources, emission is dominated by outflow components originating inside an infalling envelope. When the infall...

PACS and SPIRE photometer maps of M33 : First results of the HERschel M33 Extended Survey (HERM33ES)

NARCIS (Netherlands)

Kramer, C.; Buchbender, C.; Xilouris, E. M.; Boquien, M.; Braine, J.; Calzetti, D.; Lord, S.; Mookerjea, B.; Quintana-Lacaci, G.; Relano, M.; Stacey, G.; Tabatabaei, F. S.; Verley, S.; Aalto, S.; Akras, S.; Albrecht, M.; Anderl, S.; Beck, R.; Bertoldi, F.; Combes, F.; Dumke, M.; Garcia-Burillo, S.; Gonzalez, M.; Gratier, P.; Guesten, R.; Henkel, C.; Israel, F. P.; Koribalski, B.; Lundgren, A.; Martin-Pintado, J.; Roellig, M.; Rosolowsky, E.; Schuster, K. F.; Sheth, K.; Sievers, A.; Stutzki, J.; Tilanus, R.P.J.; van der Tak, F.; Wiedner, M. C.; van der Werf, Paul P.

Context. Within the framework of the HERM33ES key program, we are studying the star forming interstellar medium in the nearby, metal-poor spiral galaxy M33, exploiting the high resolution and sensitivity of Herschel. Aims. We use PACS and SPIRE maps at 100, 160, 250, 350, and 500 mu m wavelength, to

Protostellar Jets: The Revolution with ALMA

Science.gov (United States)

Podio, Linda

2017-11-01

Fast and collimated molecular jets as well as slower wide-angle outflows are observed since the earliest stages of the formation of a new star, when the protostellar embryo accretes most of its final mass from the dense parental envelope. Early theoretical studies suggested that jets have a key role in this process as they can transport away angular momentum thus allowing the star to form without reaching its break-up speed. However, an observational validation of these theories is still challenging as it requires to investigate the interface between jets and disks on scales of fractions to tens of AUs. For this reason, many questions about the origin and feedback of protostellar jets remain unanswered, e.g. are jets ubiquitous at the earliest stages of star formation? Are they launched by a magneto-centrifugal mechanism as suggested by theoretical models? Are they able to remove (enough) angular momentum? What is the jet/outflow feedback on the forming star-disk system in terms of transported mass/momentum and shock-induced chemical alterations? The advent of millimetre interferometers such as NOEMA and ALMA with their unprecedented combination of angular resolution and sensitivity are now unraveling the core of pristine jet-disk systems. While NOEMA allows to obtain the first statistically relevant surveys of protostellar jet properties and ubiquity, recent ALMA observations provide the first solid signatures of jet rotation and new insight on the chemistry of the protostellar region. I will review the most recent and exciting results obtained in the field and show how millimetre interferometry is revolutionising our comprehension of protostellar jets.

Explosive Outflows from Forming Massive Stars

OpenAIRE

Bally, J.; Ginsburg, A.; Kasliwal, M. M.

2016-01-01

AO imaging of the near IR [Fe ii] and H_2 lines and ALMA CO J = 2 − 1 data confirms the explosive nature of the BN/KL outflow in Orion. N-body interactions in compact groups may be responsible for the production of powerful, explosive protostellar outflows and luminous infrared flares. The Orion event may have been triggered by a protostellar merger. First results of a search for Orion-like events in 200 nearby galaxies with the SPitzer InfraRed Intensive Transients Survey (SPIRITS) are brief...

THE TURBULENT ORIGIN OF OUTFLOW AND SPIN MISALIGNMENT IN MULTIPLE STAR SYSTEMS

Energy Technology Data Exchange (ETDEWEB)

Offner, Stella S. R.; Lee, Katherine I.; Arce, Héctor G.; Fielding, Drummond B. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Dunham, Michael M., E-mail: soffner@astro.umass.edu [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)

2016-08-10

The protostellar outflows of wide-separation forming binaries frequently appear misaligned. We use magneto-hydrodynamic simulations to investigate the alignment of protostellar spin and molecular outflows for forming binary pairs. We show that the protostellar pairs, which form from turbulent fragmentation within a single parent core, have randomly oriented angular momentum. Although the pairs migrate to closer separations, their spins remain partially misaligned. We produce {sup 12}CO(2-1) synthetic observations of the simulations and characterize the outflow orientation in the emission maps. The CO-identified outflows exhibit a similar random distribution and are also statistically consistent with the observed distribution of molecular outflows. We conclude that the observed misalignment provides a clear signature of binary formation via turbulent fragmentation. The persistence of misaligned outflows and stellar spins following dynamical evolution may provide a signature of binary origins for more evolved multiple star systems.

THE TURBULENT ORIGIN OF OUTFLOW AND SPIN MISALIGNMENT IN MULTIPLE STAR SYSTEMS

International Nuclear Information System (INIS)

Offner, Stella S. R.; Lee, Katherine I.; Arce, Héctor G.; Fielding, Drummond B.; Dunham, Michael M.

2016-01-01

The protostellar outflows of wide-separation forming binaries frequently appear misaligned. We use magneto-hydrodynamic simulations to investigate the alignment of protostellar spin and molecular outflows for forming binary pairs. We show that the protostellar pairs, which form from turbulent fragmentation within a single parent core, have randomly oriented angular momentum. Although the pairs migrate to closer separations, their spins remain partially misaligned. We produce 12 CO(2-1) synthetic observations of the simulations and characterize the outflow orientation in the emission maps. The CO-identified outflows exhibit a similar random distribution and are also statistically consistent with the observed distribution of molecular outflows. We conclude that the observed misalignment provides a clear signature of binary formation via turbulent fragmentation. The persistence of misaligned outflows and stellar spins following dynamical evolution may provide a signature of binary origins for more evolved multiple star systems.

FAR-INFRARED LINE SPECTRA OF SEYFERT GALAXIES FROM THE HERSCHEL-PACS SPECTROMETER

International Nuclear Information System (INIS)

Spinoglio, Luigi; Pereira-Santaella, Miguel; Busquet, Gemma; Dasyra, Kalliopi M.; Calzoletti, Luca; Malkan, Matthew A.; Tommasin, Silvia

2015-01-01

We observed the far-IR fine-structure lines of 26 Seyfert galaxies with the Herschel-PACS spectrometer. These observations are complemented with Spitzer Infrared Spectrograph and Herschel SPIRE spectroscopy. We used the ionic lines to determine electron densities in the ionized gas and the [C I] lines, observed with SPIRE, to measure the neutral gas densities, while the [O I] lines measure the gas temperature, at densities below ∼10 4  cm –3 . Using the [O I]145 μm/63 μm and [S III]33/18 μm line ratios, we find an anti-correlation of the temperature with the gas density. Various fine-structure line ratios show density stratifications in these active galaxies. On average, electron densities increase with the ionization potential of the ions. The infrared lines arise partly in the narrow line region, photoionized by the active galactic nucleus (AGN), partly in H II regions photoionized by hot stars, and partly in photo-dissociated regions. We attempt to separate the contributions to the line emission produced in these different regions by comparing our observed emission line ratios to theoretical values. In particular, we tried to separate the contribution of AGNs and star formation by using a combination of Spitzer and Herschel lines, and we found that besides the well-known mid-IR line ratios, the line ratio of [O III]88 μm/[O IV]26 μm can reliably discriminate the two emission regions, while the far-IR line ratio of [C II]157 μm/[O I]63 μm is only able to mildly separate the two regimes. By comparing the observed [C II]157 μm/[N II]205 μm ratio with photoionization models, we also found that most of the [C II] emission in the galaxies we examined is due to photodissociation regions

FAR-INFRARED LINE SPECTRA OF SEYFERT GALAXIES FROM THE HERSCHEL-PACS SPECTROMETER

Energy Technology Data Exchange (ETDEWEB)

Spinoglio, Luigi; Pereira-Santaella, Miguel; Busquet, Gemma [Istituto di Astrofisica e Planetologia Spaziali, INAF, Via Fosso del Cavaliere 100, I-00133 Roma (Italy); Dasyra, Kalliopi M. [Observatoire de Paris, LERMA (CNRS:UMR8112), 61 Av. de l' Observatoire, F-75014, Paris (France); Calzoletti, Luca [Agenzia Spaziale Italiana (ASI) Science Data Center, I-00044 Frascati (Roma) (Italy); Malkan, Matthew A. [Astronomy Division, University of California, Los Angeles, CA 90095-1547 (United States); Tommasin, Silvia, E-mail: luigi.spinoglio@iaps.inaf.it [Weizmann Institute of Science, Department of Neurobiology, Rehovot 76100 (Israel)

2015-01-20

We observed the far-IR fine-structure lines of 26 Seyfert galaxies with the Herschel-PACS spectrometer. These observations are complemented with Spitzer Infrared Spectrograph and Herschel SPIRE spectroscopy. We used the ionic lines to determine electron densities in the ionized gas and the [C I] lines, observed with SPIRE, to measure the neutral gas densities, while the [O I] lines measure the gas temperature, at densities below ∼10{sup 4} cm{sup –3}. Using the [O I]145 μm/63 μm and [S III]33/18 μm line ratios, we find an anti-correlation of the temperature with the gas density. Various fine-structure line ratios show density stratifications in these active galaxies. On average, electron densities increase with the ionization potential of the ions. The infrared lines arise partly in the narrow line region, photoionized by the active galactic nucleus (AGN), partly in H II regions photoionized by hot stars, and partly in photo-dissociated regions. We attempt to separate the contributions to the line emission produced in these different regions by comparing our observed emission line ratios to theoretical values. In particular, we tried to separate the contribution of AGNs and star formation by using a combination of Spitzer and Herschel lines, and we found that besides the well-known mid-IR line ratios, the line ratio of [O III]88 μm/[O IV]26 μm can reliably discriminate the two emission regions, while the far-IR line ratio of [C II]157 μm/[O I]63 μm is only able to mildly separate the two regimes. By comparing the observed [C II]157 μm/[N II]205 μm ratio with photoionization models, we also found that most of the [C II] emission in the galaxies we examined is due to photodissociation regions.

Herschel Studies of the Evolution and Environs of Young Stars in the DIGIT, WISH, and FOOSH Programs

Science.gov (United States)

Green, Joel D.; DIGIT OT Key Project Team; WISH GT Key Project Team; FOOSH OT1 Team

2012-01-01

The Herschel Space Observatory has enabled us to probe the physical conditions of outer disks, envelopes, and outflows of young stellar objects, including embedded objects, Herbig Ae/Be disks, and T Tauri disks. We will report on results from three projects, DIGIT, WISH, and FOOSH. The DIGIT (Dust, Ice, and Gas in Time) program (PI: Neal Evans) utilizes the full spectral range of the PACS instrument to explore simultaneously the solid and gas-phase chemistry around sources in all of these stages. WISH (Water in Star Forming Regions with Herschel, PI Ewine van Dishoeck) focuses on observations of key lines with HIFI and line scans of selected spectral regions with PACS. FOOSH (FU Orionis Objects Surveyed with Herschel, PI Joel Green) studies FU Orionis objects with full range PACS and SPIRE scans. DIGIT includes examples of low luminosity protostars, while FOOSH studies the high luminosity objects during outburst states. Rotational ladders of highly excited CO and OH emission are detected in both disks and protostars. The highly excited lines are more commonly seen in the embedded phases, where there appear to be two temperature components. Intriguingly, water is frequently detected in spectra of embedded sources, but not in the disk spectra. In addition to gas features, we explore the extent of the newly detected 69 um forsterite dust feature in both T Tauri and Herbig Ae/Be stars. When analyzed along with the Spitzer-detected dust features, these provide constraints on a population of colder crystalline material. We will present some models of individual sources, as well as some broad statistics of the emission from these stages of star and planet formation.

"TNOs are Cool": A survey of the trans-Neptunian region. XII. Thermal light curves of Haumea, 2003 VS2 and 2003 AZ84 with Herschel/PACS

Science.gov (United States)

Santos-Sanz, P.; Lellouch, E.; Groussin, O.; Lacerda, P.; Müller, T. G.; Ortiz, J. L.; Kiss, C.; Vilenius, E.; Stansberry, J.; Duffard, R.; Fornasier, S.; Jorda, L.; Thirouin, A.

2017-08-01

Context. Time series observations of the dwarf planet Haumea and the Plutinos 2003 VS2 and 2003 AZ84 with Herschel/PACS are presented in this work. Thermal emission of these trans-Neptunian objects (TNOs) were acquired as part of the "TNOs are Cool" Herschel Space Observatory key programme. Aims: We search for the thermal light curves at 100 and 160 μm of Haumea and 2003 AZ84, and at 70 and 160 μm for 2003 VS2 by means of photometric analysis of the PACS data. The goal of this work is to use these thermal light curves to obtain physical and thermophysical properties of these icy Solar System bodies. Methods: When a thermal light curve is detected, it is possible to derive or constrain the object thermal inertia, phase integral and/or surface roughness with thermophysical modeling. Results: Haumea's thermal light curve is clearly detected at 100 and 160 μm. The effect of the reported dark spot is apparent at 100 μm. Different thermophysical models were applied to these light curves, varying the thermophysical properties of the surface within and outside the spot. Although no model gives a perfect fit to the thermal observations, results imply an extremely low thermal inertia (0.73) for Haumea's surface. We note that the dark spot region appears to be only weakly different from the rest of the object, with modest changes in thermal inertia and/or phase integral. The thermal light curve of 2003 VS2 is not firmly detected at 70 μm and at 160 μm but a thermal inertia of (2 ± 0.5) MKS can be derived from these data. The thermal light curve of 2003 AZ84 is not firmly detected at 100 μm. We apply a thermophysical model to the mean thermal fluxes and to all the Herschel/PACS and Spitzer/MIPS thermal data of 2003 AZ84, obtaining a close to pole-on orientation as the most likely for this TNO. Conclusions: For the three TNOs, the thermal inertias derived from light curve analyses or from the thermophysical analysis of the mean thermal fluxes confirm the generally small

DISENTANGLING THE ENVIRONMENT OF THE FU ORIONIS CANDIDATE HBC 722 WITH HERSCHEL

International Nuclear Information System (INIS)

Green, Joel D.; Evans, Neal J. II; Merello, Manuel; Pooley, David; Kospal, Agnes; Van Kempen, Tim A.; Van Dishoeck, Ewine; Herczeg, Gregory; Quanz, Sascha P.; Henning, Thomas; Bouwman, Jeroen; Lee, Jeong-Eun; Dunham, Michael M.; Meeus, Gwendolyn; Chen, Jo-Hsin; Guedel, Manuel; Skinner, Stephen L.; Rebull, Luisa M.; Guieu, Sylvain

2011-01-01

We analyze the submillimeter emission surrounding the new FU Orionis-type object, HBC 722. We present the first epoch of observations of the active environs of HBC 722, with imaging and spectroscopy from PACS, SPIRE, and HIFI on board the Herschel Space Observatory, as well as CO J = 2-1 and 350 μm imaging (SHARC-II) with the Caltech Submillimeter Observatory. The primary source of submillimeter continuum emission in the region-2MASS 20581767+4353310-is located 16'' south-southeast of the optical flaring source while the optical and near-infrared emission is dominated by HBC 722. A bipolar outflow extends over HBC 722; the most likely driver is the submillimeter source. We detect warm (100 K) and hot (246 K) CO emission in the surrounding region, evidence of outflow-driven heating in the vicinity. The region around HBC 722 itself shows little evidence of heating driven by the new outbursting source itself.

Herschel-PACS photometry of faint stars for sensitivity performance assessment and establishment of faint FIR primary photometric standards

Science.gov (United States)

Klaas, U.; Balog, Z.; Nielbock, M.; Müller, T. G.; Linz, H.; Kiss, Cs.

2018-05-01

Aims: Our aims are to determine flux densities and their photometric accuracy for a set of seventeen stars that range in flux from intermediately bright (≲2.5 Jy) to faint (≳5 mJy) in the far-infrared (FIR). We also aim to derive signal-to-noise dependence with flux and time, and compare the results with predictions from the Herschel exposure-time calculation tool. Methods: We obtain aperture photometry from Herschel-PACS high-pass-filtered scan maps and chop/nod observations of the faint stars. The issues of detection limits and sky confusion noise are addressed by comparison of the field-of-view at different wavelengths, by multi-aperture photometry, by special processing of the maps to preserve extended emission, and with the help of large-scale absolute sky brightness maps from AKARI. This photometry is compared with flux-density predictions based on photospheric models for these stars. We obtain a robust noise estimate by fitting the flux distribution per map pixel histogram for the area around the stars, scaling it for the applied aperture size and correcting for noise correlation. Results: For 15 stars we obtain reliable photometry in at least one PACS filter, and for 11 stars we achieve this in all three PACS filters (70, 100, 160 μm). Faintest fluxes, for which the photometry still has good quality, are about 10-20 mJy with scan map photometry. The photometry of seven stars is consistent with models or flux predictions for pure photospheric emission, making them good primary standard candidates. Two stars exhibit source-intrinsic far-infrared excess: β Gem (Pollux), being the host star of a confirmed Jupiter-size exoplanet, due to emission of an associated dust disk, and η Dra due to dust emission in a binary system with a K1 dwarf. The investigation of the 160 μm sky background and environment of four sources reveals significant sky confusion prohibiting the determination of an accurate stellar flux at this wavelength. As a good model

Evolution of the outflow activity of protostars

International Nuclear Information System (INIS)

Bontemps, Sylvain

1996-01-01

After a first part describing the formation of low-mass stars (sites of stellar formation, protostellar evolution) and matter outflows from young objects (molecular flows and their origin, optical and radio jets, outflow mechanisms), this research thesis discusses the evolution of molecular flows by reprinting a published article (Evolution of outflow activity around low-mass embedded young stellar objects), and by outlining some remaining issues (differences between clouds of stellar formation, morphological evolution of molecular flows). The author then discusses the continuous radio centimetre emission: origin, systematic search for Class 0 objects by using the VLA (Very Large Array radio interferometer), presentation of a new Class 0 protostar (HH24MMS). The author reports the study of H_2 emission in the infrared: generalities on protostellar shocks, infrared jet by HH24MMS, H_2 emission at 10 microns by using the ISOCAM camera [fr

On-board Data Processing to Lower Bandwidth Requirements on an Infrared Astronomy Satellite: Case of Herschel-PACS Camera

Directory of Open Access Journals (Sweden)

Christian Reimers

2005-09-01

Full Text Available This paper presents a new data compression concept, “on-board processing,” for infrared astronomy, where space observatories have limited processing resources. The proposed approach has been developed and tested for the PACS camera from the European Space Agency (ESA mission, Herschel. Using lossy and lossless compression, the presented method offers high compression ratio with a minimal loss of potentially useful scientific data. It also provides higher signal-to-noise ratio than that for standard compression techniques. Furthermore, the proposed approach presents low algorithmic complexity such that it is implementable on the resource-limited hardware. The various modules of the data compression concept are discussed in detail.

The Herschel-PACS Legacy of Low-mass Protostars: The Properties of Warm and Hot Gas Components and Their Origin in Far-UV Illuminated Shocks

Science.gov (United States)

Karska, Agata; Kaufman, Michael J.; Kristensen, Lars E.; van Dishoeck, Ewine F.; Herczeg, Gregory J.; Mottram, Joseph C.; Tychoniec, Łukasz; Lindberg, Johan E.; Evans, Neal J., II; Green, Joel D.; Yang, Yao-Lun; Gusdorf, Antoine; Itrich, Dominika; Siódmiak, Natasza

2018-04-01

Recent observations from Herschel allow the identification of important mechanisms responsible both for the heating of the gas that surrounds low-mass protostars and for its subsequent cooling in the far-infrared. Shocks are routinely invoked to reproduce some properties of the far-IR spectra, but standard models fail to reproduce the emission from key molecules, e.g., H2O. Here, we present the Herschel Photodetector Array Camera and Spectrometer (PACS) far-IR spectroscopy of 90 embedded low-mass protostars (Class 0/I). The Herschel-PACS spectral maps, covering ∼55–210 μm with a field of view of ∼50″, are used to quantify the gas excitation conditions and spatial extent using rotational transitions of H2O, high-J CO, and OH, as well as [O I] and [C II]. We confirm that a warm (∼300 K) CO reservoir is ubiquitous and that a hotter component (760 ± 170 K) is frequently detected around protostars. The line emission is extended beyond ∼1000 au spatial scales in 40/90 objects, typically in molecular tracers in Class 0 and atomic tracers in Class I objects. High-velocity emission (≳90 km s‑1) is detected in only 10 sources in the [O I] line, suggesting that the bulk of [O I] arises from gas that is moving slower than typical jets. Line flux ratios show an excellent agreement with models of C-shocks illuminated by ultraviolet (UV) photons for pre-shock densities of ∼105 cm‑3 and UV fields 0.1–10 times the interstellar value. The far-IR molecular and atomic lines are a unique diagnostic of feedback from UV emission and shocks in envelopes of deeply embedded protostars.

Calibration of a novel type of bolometer arrays for the Herschel space observatory

International Nuclear Information System (INIS)

Billot, Nicolas

2007-01-01

The Herschel mission is a major project at the core of the European Space Agency (ESA) scientific program. The space telescope will perform observations of the universes in the far-infrared regime of the electromagnetic spectrum, which still remains little-known today. Among the many research institutes involved in the development and exploitation of this challenging observatory, the CEA designed a novel type of bolometric detectors to equip the photometer of the PACS instrument on-board the Herschel satellite. During my thesis, my task was twofold, I developed a characterisation procedure that takes advantage of unique features of CEA filled bolometer arrays and I applied it to calibrate the PACS photometer and optimize its performances in the various observing modes open to the scientific community. In this manuscript, I present the basics of infrared astronomy from its very beginning in 1800 to the European Space Agency's Herschel Space Observatory. Then, I describe past and present developments in cryogenic bolometers, emphasising new concepts introduced by CEA. I follow with an explanation of the working principles of CEA bolometer arrays, a prerequisite to grasp the strategy of the characterisation procedure that we developed. Then I expose and analyse thoroughly the results that we obtained during the calibration campaign of the PACS photometer. Finally, I express detector performances in terms of 'observational' performances that future PACS users can comprehend. (author) [fr

PACS spectroscopy of OH/IR stars

NARCIS (Netherlands)

Lombaert, R.; de Vries, B.L.; Decin, L.; Blommaert, J.A.D.L.; Royer, Pierre; De Beck, E.; de Koter, A.; Waters, L.B.F.M.

2011-01-01

Observations of high-excitation molecular emission lines can greatly increase our understanding of AGB winds, as they trace the innermost regions of the circumstellar envelope. The PACS spectrometer on-board the Herschel Space Telescope1, provides for the first time the spectral resolution and

The star-forming cores in the centre of the Trifid nebula (M 20): from Herschel to the near-infrared

Science.gov (United States)

Tapia, M.; Persi, P.; Román-Zúñiga, C.; Elia, D.; Giovannelli, F.; Sabau-Graziati, L.

2018-04-01

A new detailed infrared (IR) study of eight star-forming dense condensations (TCs) in M 20, the Trifid nebula, is presented. The aim is to determine the physical properties of the dust in such globules and establish the presence and properties of their embedded protostellar and/or young stellar population. For this, we analysed new Herschel far-IR and Calar Alto near-IR images of the region, combined with Spitzer Infrared Array Camera (Spitzer/IRAC) archival observations. We confirm the presence of several young stellar objects (YSOs), most with mid-IR colours of Class II sources in all but one of the observed cores. Five TCs are dominated in the far-IR by Class I sources with bolometric luminosities between 100 and 500 L⊙. We report the discovery of a possible counterjet to HH 399 and its protostellar engine inside the photodissociation region TC2, as well as a bipolar outflow system, signposted by symmetric H2 emission knots, embedded in TC3. The present results are compatible with previous suggestions that star formation has been active in the region for some 3 × 105 yr, and that the most recent events in some of these TCs may have been triggered by the expansion of the H II region. We also obtained a revised value for the distance to M 20 of 2.0 ± 0.1 kpc.

HERSCHEL /HIFI OBSERVATIONS OF IRC+10216: WATER VAPOR IN THE INNER ENVELOPE OF A CARBON-RICH ASYMPTOTIC GIANT BRANCH STAR

International Nuclear Information System (INIS)

Neufeld, David A.; Gonzalez-Alfonso, Eduardo; Melnick, Gary J.; Szczerba, Ryszard; Schmidt, Miroslaw; Decin, Leen; De Koter, Alex; Schoeier, Fredrik; Cernicharo, Jose

2011-01-01

We report the results of observations of 10 rotational transitions of water vapor toward the carbon-rich asymptotic giant branch (AGB) star IRC+10216 (CW Leonis), carried out with Herschel's HIFI instrument. Each transition was securely detected by means of observations using the dual beam switch mode of HIFI. The measured line ratios imply that water vapor is present in the inner outflow at small distances (≤few x 10 14 cm) from the star, confirming recent results reported by Decin et al. from observations with Herschel's PACS and SPIRE instruments. This finding definitively rules out the hypothesis that the observed water results from the vaporization of small icy objects in circular orbits. The origin of water within the dense C-rich envelope of IRC+10216 remains poorly understood. We derive upper limits on the H 17 2 O/H 16 2 O and H 18 2 O/H 16 2 O isotopic abundance ratios of ∼5 x 10 -3 (3σ), providing additional constraints on models for the origin of the water vapor in IRC+10216.

Herschel-ATLAS: Dust Temperature and Redshift Distribution of SPIRE and PACS Detected Sources Using Submillimetre Colours

Science.gov (United States)

Amblard, A.; Cooray, Asantha; Serra, P.; Temi, P.; Barton, E.; Negrello, M.; Auld, R.; Baes, M.; Baldry, I. K.; Bamford, S.;

The CHESS survey of the L1157-B1 bow-shock: high and low excitation water vapor

Science.gov (United States)

Busquet, G.; Lefloch, B.; Benedettini, M.; Ceccarelli, C.; Codella, C.; Cabrit, S.; Nisini, B.; Viti, S.; Gómez-Ruiz, A. I.; Gusdorf, A.; di Giorgio, A. M.; Wiesenfeld, L.

2014-01-01

Context. Molecular outflows powered by young protostars strongly affect the kinematics and chemistry of the natal molecular cloud through strong shocks. This results in substantial modifications of the abundance of several species. In particular, water is a powerful tracer of shocked material because of its sensitivity to both physical conditions and chemical processes. Aims: As part of the Chemical HErschel Surveys of Star-forming regions (CHESS) guaranteed time key program, we aim at investigating the physical and chemical conditions of H2O in the brightest shock region B1 of the L1157 molecular outflow. Methods: We observed several ortho- and para-H2O transitions using the HIFI and PACS instruments on board Herschel toward L1157-B1, providing a detailed picture of the kinematics and spatial distribution of the gas. We performed a large velocity gradient (LVG) analysis to derive the physical conditions of H2O shocked material, and ultimately obtain its abundance. Results: We detected 13 H2O lines with both instruments probing a wide range of excitation conditions. This is the largest data set of water lines observed in a protostellar shock and it provides both the kinematics and the spatial information of the emitting gas. The PACS maps reveal that H2O traces weak and extended emission associated with the outflow identified also with HIFI in the o-H2O line at 556.9 GHz, and a compact (~10'') bright, higher excitation region. The LVG analysis of H2O lines in the bow-shock show the presence of two gas components with different excitation conditions: a warm (Tkin ≃ 200-300 K) and dense (n(H2) ≃ (1-3) × 106 cm-3) component with an assumed extent of 10'', and a compact (~2''-5'') and hot, tenuous (Tkin ≃ 900-1400 K, n(H2) ≃ 103-4 cm-3) gas component that is needed to account for the line fluxes of high Eu transitions. The fractional abundance of the warm and hot H2O gas components is estimated to be (0.7-2) × 10-6 and (1-3) × 10-4, respectively. Finally, we

Dust, ice and gas in time (DIGIT): Herschel and Spitzer spectro-imaging of SMM3 and SMM4 in Serpens

Science.gov (United States)

Dionatos, O.; Jørgensen, J. K.; Green, J. D.; Herczeg, G. J.; Evans, N. J.; Kristensen, L. E.; Lindberg, J. E.; van Dishoeck, E. F.

2013-10-01

Context. Mid- and far-infrared observations of the environment around embedded protostars reveal a plethora of high excitation molecular and atomic emission lines. Different mechanisms for the origin of these lines have been proposed, including shocks induced by protostellar jets and radiation or heating by the embedded protostar of its immediate surroundings. Aims: By studying of the most important molecular and atomic coolants, we aim at constraining the physical conditions around the embedded protostars SMM3 and SMM4 in the Serpens molecular cloud core and measuring the CO/H2 ratio in warm gas. Methods: Spectro-imaging observations from the Spitzer Infrared Spectrograph (IRS) and the Herschel Photodetector Array Camera and Spectrometer (PACS) provide an almost complete wavelength coverage between 5 and 200 μm. Within this range, emission from all major molecular (H2, CO, H2O and OH) and many atomic ([OI], [CII], [FeII], [SiII] and [SI]) coolants of excited gas are detected. Emission line maps reveal the morphology of the observed emission and indicate associations between the different species. The excitation conditions for molecular species are assessed through rotational diagrams. Emission lines from major coolants are compared to the results of steady-state C- and J-type shock models. Results: Line emission tends to peak at distances of ~10-20″ from the protostellar sources with all but [CII] peaking at the positions of outflow shocks seen in near-IR and sub-millimeter interferometric observations. The [CII] emission pattern suggests that it is most likely excited from energetic UV radiation originating from the nearby flat-spectrum source SMM6. Excitation analysis indicates that H2 and CO originate in gas at two distinct rotational temperatures of ~300 K and 1000 K, while the excitation temperature for H2O and OH is ~100-200 K. The morphological and physical association between CO and H2 suggests a common excitation mechanism, which allows direct

ANALYSIS OF THE HERSCHEL /HEXOS SPECTRAL SURVEY TOWARD ORION SOUTH: A MASSIVE PROTOSTELLAR ENVELOPE WITH STRONG EXTERNAL IRRADIATION

Energy Technology Data Exchange (ETDEWEB)

Tahani, K.; Plume, R. [Department of Physics and Astronomy, University of Calgary, Calgary, AB T2N 1N4 (Canada); Bergin, E. A. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Tolls, V. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Phillips, T. G.; Lis, D. C. [California Institute of Technology, Cahill Center for Astronomy and Astrophysics 301-17, Pasadena, CA 91125 (United States); Caux, E. [Université de Toulouse, UPS-OMP, IRAP, F-31028 Toulouse (France); Cabrit, S.; Pagani, L. [LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, F-75014, Paris (France); Goicoechea, J. R. [Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC). Sor Juana Ines de la Cruz 3, E-28049 Cantoblanco, Madrid (Spain); Goldsmith, P. F.; Pearson, J. C. [Jet Propulsion Laboratory, Caltech, Pasadena, CA 91109 (United States); Johnstone, D. [National Research Council Canada, Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Menten, K. M. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Müller, H. S. P.; Ossenkopf-Okada, V. [I. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, D-50937 Köln (Germany); Tak, F. F. S. van der, E-mail: ktahani@ucalgary.ca [SRON Netherlands Institute for Space Research, P.O. Box 800, 9700 AV, Groningen (Netherlands)

2016-11-20

We present results from a comprehensive submillimeter spectral survey toward the source Orion South, based on data obtained with the Heterodyne Instrument for the Far-Infrared instrument on board the Herschel Space Observatory , covering the frequency range of 480 to 1900 GHz. We detect 685 spectral lines with signal-to-noise ratios (S/Ns) > 3 σ , originating from 52 different molecular and atomic species. We model each of the detected species assuming conditions of Local Thermodynamic Equilibrium. This analysis provides an estimate of the physical conditions of Orion South (column density, temperature, source size, and V {sub LSR}). We find evidence for three different cloud components: a cool ( T {sub ex} ∼ 20–40 K), spatially extended (>60″), and quiescent (Δ V {sub FWHM} ∼ 4 km s{sup -1}) component; a warmer ( T {sub ex} ∼ 80–100 K), less spatially extended (∼30″), and dynamic (Δ V {sub FWHM} ∼ 8 km s{sup -1}) component, which is likely affected by embedded outflows; and a kinematically distinct region ( T {sub ex} > 100 K; V {sub LSR} ∼ 8 km s{sup -1}), dominated by emission from species that trace ultraviolet irradiation, likely at the surface of the cloud. We find little evidence for the existence of a chemically distinct “hot-core” component, likely due to the small filling factor of the hot core or hot cores within the Herschel beam. We find that the chemical composition of the gas in the cooler, quiescent component of Orion South more closely resembles that of the quiescent ridge in Orion-KL. The gas in the warmer, dynamic component, however, more closely resembles that of the Compact Ridge and Plateau regions of Orion-KL, suggesting that higher temperatures and shocks also have an influence on the overall chemistry of Orion South.

Do protostellar fountains shape the regional core mass function?

International Nuclear Information System (INIS)

Li Jin-Zeng; Huang Ya-Fang; Carlos Mallamaci Claudio; César Podestà Ricardo; Actis Vicente Eloy; Maria Pacheco Ana

2013-01-01

The emerging massive binary system associated with AFGL 961 signifies the latest generation of massive star and cluster formation in the Rosette Molecular Complex. We present the detection of a compact cluster of dusty cores toward the AFGL 961 region based on continuum imaging at 1.3 mm by the Submillimeter Array. The binary components of AFGL 961 are associated with the most intensive millimeter emission cores or envelopes, confirming that they are indeed in an early stage of evolution. The other massive cores, however, are found to congregate in the close vicinity of the central high-mass protostellar binary. They have no apparent infrared counterparts and are, in particular, well aligned transverse to the bipolar molecular outflows originating from AFGL 961. This provides evidence for a likely triggered origin of the massive cores. All 40 individual cores with masses ranging between 0.6 and 15 Msun were detected above a 3 σ level of 3.6 mJy beam −1 (or 0.4 Msun), based on which we derive a total core mass of 107 Msun in the AFGL 961 region. As compared to the stellar initial mass function, a shallow slope of 1.8 is, however, derived from the best fit to the mass spectrum of the millimeter cores with a prestellar and/or protostellar origin. The flatter core mass distribution in the AFGL 961 region is attributed here to dynamic perturbations from the massive molecular outflows that originated from the massive protostellar binary, which may have altered the otherwise more quiescent conditions of core or star formation, enhanced the formation of more massive cores and, as a result, influenced the core mass distribution in its close vicinity.

HERSCHEL KEY PROGRAM, ''DUST, ICE, AND GAS IN TIME'' (DIGIT): THE ORIGIN OF MOLECULAR AND ATOMIC EMISSION IN LOW-MASS PROTOSTARS IN TAURUS

Energy Technology Data Exchange (ETDEWEB)

Lee, Jeong-Eun; Lee, Seokho [Department of Astronomy and Space Science, Kyung Hee University, Yongin-shi, Kyungki-do 449-701 (Korea, Republic of); Lee, Jinhee [Department of Physics and Astronomy, The University of Georgia, Athens, GA 30602-2451 (United States); Evans II, Neal J.; Green, Joel D., E-mail: jeongeun.lee@khu.ac.kr [Department of Astronomy, University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712-1205 (United States)

2014-10-01

Six low-mass embedded sources (L1489, L1551-IRS5, TMR1, TMC1-A, L1527, and TMC1) in Taurus have been observed with Herschel-PACS to cover the full spectrum from 50 to 210 μm as part of the Herschel key program, ''Dust, Ice, and Gas In Time''. The relatively low intensity of the interstellar radiation field surrounding Taurus minimizes contamination of the [C II] emission associated with the sources by diffuse emission from the cloud surface, allowing study of the [C II] emission from the source. In several sources, the [C II] emission is distributed along the outflow, as is the [O I] emission. The atomic line luminosities correlate well with each other, as do the molecular lines, but the atomic and molecular lines correlate poorly. The relative contribution of CO to the total gas cooling is constant at ∼30%, while the cooling fraction by H{sub 2}O varies from source to source, suggesting different shock properties resulting in different photodissociation levels of H{sub 2}O. The gas with a power-law temperature distribution with a moderately high density can reproduce the observed CO fluxes, indicative of CO close to LTE. However, H{sub 2}O is mostly subthermally excited. L1551-IRS5 is the most luminous source (Ł{sub bol} = 24.5 L {sub ☉}) and the [O I] 63.1 μm line accounts for more than 70% of its FIR line luminosity, suggesting complete photodissociation of H{sub 2}O by a J shock. In L1551-IRS5, the central velocity shifts of the [O I] line, which exceed the wavelength calibration uncertainty (∼70 km s{sup –1}) of PACS, are consistent with the known redshifted and blueshifted outflow direction.

SYNTHETIC OBSERVATIONS OF MAGNETIC FIELDS IN PROTOSTELLAR CORES

International Nuclear Information System (INIS)

Lee, Joyce W. Y.; Hull, Charles L. H.; Offner, Stella S. R.

2017-01-01

The role of magnetic fields in the early stages of star formation is not well constrained. In order to discriminate between different star formation models, we analyze 3D magnetohydrodynamic simulations of low-mass cores and explore the correlation between magnetic field orientation and outflow orientation over time. We produce synthetic observations of dust polarization at resolutions comparable to millimeter-wave dust polarization maps observed by the Combined Array for Research in Millimeter-wave Astronomy and compare these with 2D visualizations of projected magnetic field and column density. Cumulative distribution functions of the projected angle between the magnetic field and outflow show different degrees of alignment in simulations with differing mass-to-flux ratios. The distribution function for the less magnetized core agrees with observations finding random alignment between outflow and field orientations, while the more magnetized core exhibits stronger alignment. We find that fractional polarization increases when the system is viewed such that the magnetic field is close to the plane of the sky, and the values of fractional polarization are consistent with observational measurements. The simulation outflow, which reflects the underlying angular momentum of the accreted gas, changes direction significantly over over the first ∼0.1 Myr of evolution. This movement could lead to the observed random alignment between outflows and the magnetic fields in protostellar cores.

An extended Herschel drop-out source in the center of AS1063 : a normal dusty galaxy at z = 6.1 or SZ substructures?

NARCIS (Netherlands)

Boone, F.; Clément, B.; Richard, J.; Schaerer, D.; Lutz, D.; Weiß, A.; Zemcov, M.; Egami, E.; Rawle, T.; Walth, G.; Kneib, J.; Combes, F.; Smail, I.; Swinbank, A.; Altieri, B.; Blain, A.; Chapman, S.; Dessauges-Zavadsky, M.; Ivison, R.; Knudsen, K.; Omont, A.; Pelló, R.; Pérez-González, P.; Valtchanov, I.; Werf, van der P.P.; Zamojski, M.

2013-01-01

In the course of our 870 {$μ$}m APEX/LABOCA follow-up of the Herschel Lensing Survey we have detected a source in AS1063 (RXC J2248.7-4431) that has no counterparts in any of the Herschel PACS/SPIRE bands, it is a Herschel ''drop-out'' with S$_{870}$/S$_{500}$ {ge} 0.5. The 870 {$μ$}m emission is

VizieR Online Data Catalog: Herschel FIR spectra of GOALS galaxies (Diaz-Santos+, 2017)

Science.gov (United States)

Diaz-Santos, T.; Armus, L.; Charmandaris, V.; Lu, N.; Stierwalt, S.; Stacey, G.; Malhotra, S.; van der Werf, P. P.; Howell, J. H.; Privon, G. C.; Mazzarella, J. M.; Goldsmith, P. F.; Murphy, E. J.; Barcos-Munoz, L.; Linden, S. T.; Inami, H.; Larson, K. L.; Evans, A. S.; Appleton, P.; Iwasawa, K.; Lord, S.; Sanders, D. B.; Surace, J. A.

2018-04-01

We have obtained FIR spectroscopic observations for 200 luminous infrared galaxies (LIRG) systems from the Great Observatories All-Sky LIRG Survey (GOALS; Armus+ 2009PASP..121..559A) using the Integral Field Spectrometer (IFS) of the PACS instrument on board Herschel. Since some targets contain multiple components, there are 241 individual galaxies with available spectra in at least one emission line. Most of the data were collected as part of our OT1 and OT2 programs (OT1larmus1, OT2larmus1; P.I.: L. Armus), accounting for more than 200hr of observing time in total. Additional observations that are publicly available in the Herschel archive were included from various projects. The main programs from where these complementary data were gathered are KPGTesturm1 (P.I.: E. Sturm), KPOTpvanderw1 (PI: P. van der Werf), and OT1dweedman1 (P.I.: D. Weedman). The IFS on PACS is able to perform simultaneous spectroscopy in the 51-73 or 70-105um and the 102-210um ranges. In addition to the PACS/IFS spectra, we obtained observations of the [NII]205 emission line using the SPIRE FTS for 121 galaxies in the GOALS sample (Lu+ 2017, J/ApJS/230/1 ; OT1nlu1; P.I.: N. Lu). As part of the Spitzer GOALS legacy program, all galaxies observed with Herschel/PACS have available Spitzer/IRS low-resolution, R~60-120 (SL module: 5.2-14.5um; LL module: 14-38um), and medium-resolution, R~600 (SH module: 9.9-19.6um; LH module: 18.7-37.2um), slit spectroscopy. (3 data files).

Detection of warm water vapour in Taurus protoplanetary discs by Herschel

NARCIS (Netherlands)

Riviere-Marichalar, P.; Menard, F.; Thi, W. F.; Kamp, I.; Montesinos, B.; Meeus, G.; Woitke, P.; Howard, C.; Sandell, G.; Podio, L.; Dent, W. R. F.; Mendigutia, I.; Pinte, C.; White, G. J.; Barrado, D.

Line spectra of 68 Taurus T Tauri stars were obtained with the Herschel-PACS (Photodetector Array Camera and Spectrometer) instrument as part of the GASPS (GAS evolution in Protoplanetary Systems) survey of protoplanetary discs. A careful examination of the linescans centred on the [OI] 63.18 mu m

"Heart" of Herschel to be presented to media

Science.gov (United States)

2007-09-01

instruments were designed and built by consortia of scientists and institutes, with their own national funding. The Photodetector Array Camera and Spectrometer (PACS) was developed under the coordination of the MPE, Germany; the Spectral and Photometric Imaging Receiver (SPIRE) was developed under the coordination of the Cardiff University (United Kingdom); the Heterodyne Instrument for the Far Infrared (HIFI) was developed under the coordination of the SRON institute (The Netherlands). For more information ESA Media Relations Office Tel: +33(0)1.53.69.7299 Fax: +33(0)1.53.69.7690 Herschel Press Day at Astrium, Friedrichshafen, Germany 19 September 2007 Claude-Dornier-Strasse 88090 Immenstaad 09:00 h Arrival at Astrium /Check-in / Transfer to Building 8 / Room Meersburg (5 th floor) 09:30 h Welcome, by Uwe Minne, Director of Earth Observation and Science, Astrium 09:35 h ESA and Astronomy: looking forward, by Jacques Louet, Head of Scientific Projects Department, ESA 09:45 h Herschel/Planck mission overview, by Thomas Passvogel, ESA Herschel/Planck Project Manager 09:55 h The Herschel scientific mission, by Göran Pilbratt, ESA Herschel Project Scientist 10:05 h Q & A followed by coffee break 10:30 h Herschel spacecraft overview, by Jean-Jacques Julliet, Director of European Science and Optical Observation Programmes, Thales Alenia Space 10:40 h The ‘cool’ heart of Herschel, by Wolfgang Fricke, Herschel Project Manager, Astrium 10:50 h The PACS instrument, by Albrecht Poglitsch, Principal Investigator, Max-Planck-Institut für extraterrestrische Physik (MPE) 11:00 h The SPIRE instrument, by Matthew Griffin, Principal Investigator, Cardiff University 11:10 h The HIFI instrument, by Thijs de Graauw, Principal Investigator, Netherlands Institute for Space Research (SRON) 11:20 h Q & A, Individual Interviews 12:15 h Transfer to Integration Centre 12:30 h Warm / Cold Buffet on Visitoŕs Galaxy Build up of three different visitor groups Check-in into cleanroom Photo

Revealing the ISM in high redshift starburst galaxies: An analysis of Herschel PACS and SPIRE FTS spectroscopic observations of HerMES and H-ATLAS-selected lensed galaxies

Science.gov (United States)

Cooray, Asantha

In the quest to develop a fundamental understanding of galaxy formation and evolution, observations of dusty star-forming galaxies (DSFGs) promise significant progress this decade. The importance of DSFGs is highlighted by the fact that half of the energy emitted by extragalactic sources emerges as dust-reprocessed light at infrared (IR) to sub millimeter wavelength. In the post-herschel\\ era, we are now at a unique position to tackle some of the key questions on galaxy formation and evolution because of the large area Herschel's Key Project surveys (HerMES and H-ATLAS). In particular those surveys have allowed us to identify a sample of 250 strongly gravitationally lensed DSFGs at z > 1. They give us a unique opportunity to dissect the detailed structures and kinematics of DSFGs. The Herschel Science Archive also contains individual follow up data on 44 and 25 of the brightest sources with SPIRE-FTS and PACS, respectively, in the spectroscopy mode, taking over 250 hours in four open-time programs. Only one of the 44 SPIRE FTS targets has yet to appear in the published literature. One of the four include an open-time 2 PACS spectroscopy program that was led at UCI by a former postdoc from the PI's group. That program was initially approved at Priority 2 in 2011, but was triggered in late 2012 and achieved 100% completion during the last two weeks of Herschel lifetime in May 2013. This archival analysis, interpretation, and modeling program involves two parts: (i) PACS spectroscopy in 50 to 200 microns of 25 lensed galaxies in the fine-structure emission lines [SiII]34, [SIII]33, [OIV]26, [OIII]52, [NIII]57 and [OI]63, and the molecular hydrogen H_2 S(0) and S(1). (ii) SPIRE FTS spectroscopy of 44 lensed galaxies, including above 25, over the wavelength range of 200 to 600 microns targeting [CII]158, [OIII]88, [OI]63/145, and [NI]122. The analysis will lead to a better understanding of the ISM of starbursting galaxies that span 1 research supports Goal 2 of the

Water in star-forming regions with Herschel (WISH). V. The physical conditions in low-mass protostellar outflows revealed by multi-transition water observations

NARCIS (Netherlands)

Mottram, J. C.; Kristensen, L. E.; van Dishoeck, E. F.; Bruderer, S.; San José-García, I.; Karska, A.; Visser, R.; Santangelo, G.; Benz, A. O.; Bergin, E. A.; Caselli, P.; Herpin, F.; Hogerheijde, M. R.; Johnstone, D.; van Kempen, T. A.; Liseau, R.; Nisini, B.; Tafalla, M.; van der Tak, F. F. S.; Wyrowski, F.

2014-01-01

Context. Outflows are an important part of the star formation process as both the result of ongoing active accretion and one of the main sources of mechanical feedback on small scales. Water is the ideal tracer of these effects because it is present in high abundance for the conditions expected in

HERSCHEL FAR-INFRARED SPECTRAL-MAPPING OF ORION BN/KL OUTFLOWS: SPATIAL DISTRIBUTION OF EXCITED CO, H{sub 2}O, OH, O, AND C{sup +} IN SHOCKED GAS

Energy Technology Data Exchange (ETDEWEB)

Goicoechea, Javier R.; Cernicharo, José; Cuadrado, Sara; Etxaluze, Mireya [Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC). Sor Juana Ines de la Cruz 3, E-28049 Cantoblanco, Madrid (Spain); Chavarría, Luis [Centro de Astrobiología, CSIC-INTA, Ctra. de Torrejón a Ajalvir km 4, E-28850 Madrid (Spain); Neufeld, David A. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Vavrek, Roland [Herschel Science Center, ESA/ESAC, P.O. Box 78, Villanueva de la Cañada, E-28691 Madrid (Spain); Bergin, Edwin A. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Encrenaz, Pierre [LERMA, UMR 8112 du CNRS, Observatoire de Paris, École Normale Supérieure, F-75014 Paris (France); Melnick, Gary J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 66, Cambridge, MA 02138 (United States); Polehampton, Edward, E-mail: jr.goicoechea@icmm.csic.es [RAL Space, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX (United Kingdom)

2015-01-20

We present ∼2' × 2' spectral-maps of Orion Becklin-Neugebauer/Kleinmann-Low (BN/KL) outflows taken with Herschel at ∼12'' resolution. For the first time in the far-IR domain, we spatially resolve the emission associated with the bright H{sub 2} shocked regions ''Peak 1'' and ''Peak 2'' from that of the hot core and ambient cloud. We analyze the ∼54-310 μm spectra taken with the PACS and SPIRE spectrometers. More than 100 lines are detected, most of them rotationally excited lines of {sup 12}CO (up to J = 48-47), H{sub 2}O, OH, {sup 13}CO, and HCN. Peaks 1/2 are characterized by a very high L(CO)/L {sub FIR} ≈ 5 × 10{sup –3} ratio and a plethora of far-IR H{sub 2}O emission lines. The high-J CO and OH lines are a factor of ≈2 brighter toward Peak 1 whereas several excited H{sub 2}O lines are ≲50% brighter toward Peak 2. Most of the CO column density arises from T {sub k} ∼ 200-500 K gas that we associate with low-velocity shocks that fail to sputter grain ice mantles and show a maximum gas-phase H{sub 2}O/CO ≲ 10{sup –2} abundance ratio. In addition, the very excited CO (J > 35) and H{sub 2}O lines reveal a hotter gas component (T {sub k} ∼ 2500 K) from faster (v {sub S} > 25 km s{sup –1}) shocks that are able to sputter the frozen-out H{sub 2}O and lead to high H{sub 2}O/CO ≳ 1 abundance ratios. The H{sub 2}O and OH luminosities cannot be reproduced by shock models that assume high (undepleted) abundances of atomic oxygen in the preshock gas and/or neglect the presence of UV radiation in the postshock gas. Although massive outflows are a common feature in other massive star-forming cores, Orion BN/KL seems more peculiar because of its higher molecular luminosities and strong outflows caused by a recent explosive event.

The CHESS survey of the L1157-B1 bow-shock: Dissecting the water content

Science.gov (United States)

Busquet, Gemma; Lefloch, Bertrand; Benedettini, Milena; Ceccarelli, Cecilia; Codella, Claudio; Cabrit, Sylvie; Nisini, Brunella; Viti, Serena; Gómez-Ruiz, Arturo; Gusdorf, Antoine; Di Giorgio, Anna Maria; Wiesenfeld, Laurent

2013-07-01

Molecular outflows powered by young protostars strongly affect the kinematics and chemistry of the natal molecular cloud through strong shocks, resulting in an increase of the abundance of several species. In particular, water is a powerful tracer of shocked material due to its sensitivity to both physical conditions and chemical processes. The observations of the "Chemical Herschel Survey of Star forming regions" (CHESS) key program towards the shock region L1157-B1 offered a unique and comprehensive view of the water emission in a typical protostellar bow shock across the submillimeter and far-infrared window. A grand total of 13 water lines have been detected with the PACS and HIFI instruments, probing a wide range of excitation conditions and providing us with a detailed picture on both the kinematics and the spatial distribution of water emission. Several gas components have been identified coexisting in the L1157-B1 shock region. Large Velocity Gradient (LVG) analysis reveals that these components have different excitation conditions: i) a warm (T~250 K) and dense (n(H2)~10^6 cm-3) gas component seen also with the CO lines and associated with the partly dissociative shock produced by the impact of the protostellar jet against the bow shock; ii) a compact (size~5''), hot (T~700 K), and less dense (n(H2)~10^4 cm-3) gas component, and iii) an extended component associated with the B1 outflow cavity. These three components present clear differences in terms of water enrichment. Finally, we confront the physical and chemical properties of the H2O emission to the predictions of current shock models.

HERSCHEL -RESOLVED OUTER BELTS OF TWO-BELT DEBRIS DISKS—EVIDENCE OF ICY GRAINS

Energy Technology Data Exchange (ETDEWEB)

Morales, F. Y.; Bryden, G.; Werner, M. W.; Stapelfeldt, K. R., E-mail: Farisa@jpl.nasa.gov [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)

2016-11-01

We present dual-band Herschel /PACS imaging for 59 main-sequence stars with known warm dust ( T {sub warm} ∼ 200 K), characterized by Spitzer . Of 57 debris disks detected at Herschel wavelengths (70 and/or 100 and 160 μ m), about half have spectral energy distributions (SEDs) that suggest two-ring disk architectures mirroring that of the asteroid–Kuiper Belt geometry; the rest are consistent with single belts of warm, asteroidal material. Herschel observations spatially resolve the outer/cold dust component around 14 A-type and 4 solar-type stars with two-belt systems, 15 of which for the first time. Resolved disks are typically observed with radii >100 AU, larger than expected from a simple blackbody fit. Despite the absence of narrow spectral features for ice, we find that the shape of the continuum, combined with resolved outer/cold dust locations, can help constrain the grain size distribution and hint at the dust’s composition for each resolved system. Based on the combined Spitzer /IRS+Multiband Imaging Photometer (5-to-70 μ m) and Herschel /PACS (70-to-160 μ m) data set, and under the assumption of idealized spherical grains, we find that over half of resolved outer/cold belts are best fit with a mixed ice/rock composition. Minimum grain sizes are most often equal to the expected radiative blowout limit, regardless of composition. Three of four resolved systems around the solar-type stars, however, tend to have larger minimum grains compared to expectation from blowout ( f {sub MB} = a {sub min}/ a {sub BOS} ∼ 5). We also probe the disk architecture of 39 Herschel -unresolved systems by modeling their SEDs uniformly, and find them to be consistent with 31 single- and 8 two-belt debris systems.

Herschel GASPS spectral observations of T Tauri stars in Taurus. Unraveling far-infrared line emission from jets and discs

NARCIS (Netherlands)

Alonso-Martínez, M.; Riviere-Marichalar, P.; Meeus, G.; Kamp, I.; Fang, M.; Podio, L.; Dent, W. R. F.; Eiroa, C.

2017-01-01

Context. At early stages of stellar evolution young stars show powerful jets and/or outflows that interact with protoplanetary discs and their surroundings. Despite the scarce knowledge about the interaction of jets and/or outflows with discs, spectroscopic studies based on Herschel and ISO data

HERSCHEL/PACS SURVEY OF PROTOPLANETARY DISKS IN TAURUS/AURIGA—OBSERVATIONS OF [O I] AND [C II], AND FAR-INFRARED CONTINUUM

International Nuclear Information System (INIS)

Howard, Christian D.; Sandell, Göran; Vacca, William D.; Duchêne, Gaspard; Mathews, Geoffrey; Augereau, Jean-Charles; Ménard, Francois; Pinte, Christophe; Podio, Linda; Thi, Wing-Fai; Barrado, David; Riviere-Marichalar, Pablo; Dent, William R. F.; Eiroa, Carlos; Meeus, Gwendolyn; Grady, Carol; Roberge, Aki; Kamp, Inga; Vicente, Silvia; Williams, Jonathan P.

2013-01-01

The Herschel Space Observatory was used to observe ∼120 pre-main-sequence stars in Taurus as part of the GASPS Open Time Key project. Photodetector Array Camera and Spectrometer was used to measure the continuum as well as several gas tracers such as [O I] 63 μm, [O I] 145 μm, [C II] 158 μm, OH, H 2 O, and CO. The strongest line seen is [O I] at 63 μm. We find a clear correlation between the strength of the [O I] 63 μm line and the 63 μm continuum for disk sources. In outflow sources, the line emission can be up to 20 times stronger than in disk sources, suggesting that the line emission is dominated by the outflow. The tight correlation seen for disk sources suggests that the emission arises from the inner disk (<50 AU) and lower surface layers of the disk where the gas and dust are coupled. The [O I] 63 μm is fainter in transitional stars than in normal Class II disks. Simple spectral energy distribution models indicate that the dust responsible for the continuum emission is colder in these disks, leading to weaker line emission. [C II] 158 μm emission is only detected in strong outflow sources. The observed line ratios of [O I] 63 μm to [O I] 145 μm are in the regime where we are insensitive to the gas-to-dust ratio, neither can we discriminate between shock or photodissociation region emission. We detect no Class III object in [O I] 63 μm and only three in continuum, at least one of which is a candidate debris disk

Water in Star-forming Regions with Herschel (WISH): recent results and trends

Science.gov (United States)

van Dishoeck, E. F.

2012-03-01

Water is a key molecule in the physics and chemistry of star- and planet-forming regions. In the `Water in Star-forming Regions with Herschel' (WISH) Key Program, we have obtained a comprehensive set of water data toward a large sample of well-characterized protostars, covering a wide range of masses and luminosities --from the lowest to the highest mass protostars--, as well as evolutionary stages --from pre-stellar cores to disks. Lines of both ortho- and para-H_2O and their isotopologues, as well as chemically related hydrides, are observed with the HIFI and PACS instruments. The data elucidate the physical processes responsible for the warm gas, probe dynamical processes associated with forming stars and planets (outflow, infall, expansion), test basic chemical processes and reveal the chemical evolution of water and the oxygen-reservoir into planet-forming disks. In this brief talk a few recent WISH highlights will be presented, including determinations of the water abundance in each of the different physical components (inner and outer envelope, outflow) and constraints on the ortho/para ratio. Special attention will be given to trends found across the sample, especially the similarity in profiles from low to high-mass protostars and the evolution of the gas-phase water abundance from prestellar cores to disks. More details can be found at http://www.strw.leidenuniv.nl/WISH, whereas overviews are given in van Dishoeck et al. (2011, PASP 123, 138), Kristensen & van Dishoeck (2011, Astronomische Nachrichten 332, 475) and Bergin & van Dishoeck (2012, Phil. Trans. Royal Soc. A).

GOODS-Herschel: identification of the individual galaxies responsible for the 80-290 μm cosmic infrared background

Science.gov (United States)

Leiton, R.; Elbaz, D.; Okumura, K.; Hwang, H. S.; Magdis, G.; Magnelli, B.; Valtchanov, I.; Dickinson, M.; Béthermin, M.; Schreiber, C.; Charmandaris, V.; Dole, H.; Juneau, S.; Le Borgne, D.; Pannella, M.; Pope, A.; Popesso, P.

2015-07-01

Aims: We propose a new method of pushing Herschel to its faintest detection limits using universal trends in the redshift evolution of the far infrared over 24 μm colours in the well-sampled GOODS-North field. An extension to other fields with less multi-wavelength information is presented. This method is applied here to raise the contribution of individually detected Herschel sources to the cosmic infrared background (CIRB) by a factor 5 close to its peak at 250 μm and more than 3 in the 350 and 500 μm bands. Methods: We produce realistic mock Herschel images of the deep PACS and SPIRE images of the GOODS-North field from the GOODS-Herschel key program and use them to quantify the confusion noise at the position of individual sources, i.e., estimate a "local confusion noise". Two methods are used to identify sources with reliable photometric accuracy extracted using 24 μm prior positions. The clean index (CI), previously defined but validated here with simulations, which measures the presence of bright 24 μm neighbours and the photometric accuracy index (PAI) directly extracted from the mock Herschel images. Results: Both methods converge to comparable depths and fractions of the CIRB resolved into sources individually detected with Herschel. After correction for completeness, thanks to our mock Herschel images, individually detected sources make up as much as 54% and 60% of the CIRB in the PACS bands down to 1.1 mJy at 100 μm and 2.2 mJy at 160 μm and 55, 33, and 13% of the CIRB in the SPIRE bands down to 2.5, 5, and 9 mJy at 250 μm, 350 μm, and 500 μm, respectively. The latter depths improve the detection limits of Herschel by factors of 5 at 250 μm, and 3 at 350 μm and 500 μm as compared to the standard confusion limit. Interestingly, the dominant contributors to the CIRB in all Herschel bands appear to be distant siblings of the Milky Way (z ~ 0.96 for λ< 300 μm) with a stellar mass of M⋆ ~ 9 × 1010M⊙.

Ionized and Neutral Outflows in the QUEST QSOs

Science.gov (United States)

Veilleux, Sylvain

2011-10-01

The role of galactic winds in gas-rich mergers is of crucial importance to understand galaxy and SMBH evolution. In recent months, our group has had three major scientific breakthroughs in this area: {1} The discovery with Herschel of massive molecular {OH-absorbing} outflows in several ULIRGs, including the nearest quasar, Mrk 231. {2} The independent discovery from mm-wave interferometric observations in the same object of a spatially resolved molecular {CO-emitting} wind with estimated mass outflow rate 3x larger than the star formation rate and spatially coincident with blueshifted neutral {Na ID-absorbing} gas in optical long-slit spectra. {3} The unambiguous determination from recent Gemini/IFU observations that the Na ID outflow in this object is wide-angle, thus driven by a QSO wind rather than a jet. This powerful outflow may be the long-sought "smoking gun" of quasar mechanical feedback purported to transform gas-rich mergers. However, our Herschel survey excludes all FIR-faint {UV-bright} "classic" QSOs by necessity. So here we propose a complementary FUV absorption-line survey of all FIR-bright -and- FIR-faint QSOs from the same parent sample. New {19 targets} and archival {11} spectra will be used to study, for the first time, the gaseous environments of QSOs as a function of host properties and age across the merger sequence ULIRG -> QSO. These data will allow us to distinguish between ionized & neutral quasar-driven outflows, starburst-driven winds, and tidal debris around the mergers. They will also be uniquely suited for a shallow but broad study of the warm & warm-hot intergalactic media, complementary to on-going surveys that are deeper but narrower.

DISENTANGLING THE ENTANGLED: OBSERVATIONS AND ANALYSIS OF THE TRIPLE NON-COEVAL PROTOSTELLAR SYSTEM VLA1623

International Nuclear Information System (INIS)

Murillo, Nadia M.; Lai, Shih-Ping

2013-01-01

Commonplace at every evolutionary stage, multiple protostellar systems (MPSs) are thought to be formed through fragmentation, but it is unclear when and how. The youngest MPSs, which have not yet undergone much evolution, provide important constraints to this question. It is then of interest to disentangle early stage MPSs. In this Letter we present the results of our work on VLA1623 using our observations and archival data from the Submillimeter Array. Our continuum and line observations trace VLA1623's components, outflow, and envelope, revealing unexpected characteristics. We construct the spectral energy distribution (SED) for each component using the results of our work and data from literature, as well as derive physical parameters from continuum and perform a simple kinematical analysis of the circumstellar material. Our results show VLA1623 to be a triple non-coeval system composed of VLA1623A, B, and W, with each source driving its own outflow and unevenly distributed circumstellar material. From the SED, physical parameters, and IR emission we conclude that VLA1623A and W are Class 0 and Class I protostars, respectively, and together drive the bulk of the observed outflow. Furthermore, we find two surprising results, first the presence of a rotating disk-like structure about VLA1623A with indications of pure Keplerian rotation, which, if real, would make it one of the first evidence of Keplerian disk structures around Class 0 protostars. Second, we find VLA1623B to be a bona fide extremely young protostellar object between the starless core and Class 0 stages.

Modeling the HD 32297 Debris Disk With Far-Infrared Herschel Data

Science.gov (United States)

Donaldson, J.K.; Lebreton, J.; Roberge, A.; Augereau, J.-C.; Krivov, A. V.

2013-01-01

HD 32297 is a young A-star (approx. 30 Myr) 112 pc away with a bright edge-on debris disk that has been resolved in scattered light. We observed the HD 32297 debris disk in the far-infrared and sub-millimeter with the Herschel Space Observatory PACS and SPIRE instruments, populating the spectral energy distribution (SED) from 63 to 500 micron..We aimed to determine the composition of dust grains in the HD 32297 disk through SED modeling, using geometrical constraints from the resolved imaging to break the degeneracies inherent in SED modeling. We found the best fitting SED model has two components: an outer ring centered around 110 AU, seen in the scattered light images, and an inner disk near the habitable zone of the star. The outer disk appears to be composed of grains>2 micron consisting of silicates, carbonaceous material, and water ice with an abundance ratio of 1:2:3 respectively and 90% porosity. These grains appear consistent with cometary grains, implying the underlying planetesimal population is dominated by comet-like bodies. We also discuss the 3.7 sigma detection of [C ii] emission at 158 micron with the Herschel PACS instrument, making HD 32297 one of only a handful of debris disks with circumstellar gas detected

BROAD N2H+ EMISSION TOWARD THE PROTOSTELLAR SHOCK L1157-B1

International Nuclear Information System (INIS)

Codella, C.; Fontani, F.; Gómez-Ruiz, A.; Vasta, M.; Viti, S.; Ceccarelli, C.; Lefloch, B.; Podio, L.; Benedettini, M.; Busquet, G.; Caselli, P.

2013-01-01

We present the first detection of N 2 H + toward a low-mass protostellar outflow, namely, the L1157-B1 shock, at ∼0.1 pc from the protostellar cocoon. The detection was obtained with the IRAM 30 m antenna. We observed emission at 93 GHz due to the J = 1-0 hyperfine lines. Analysis of this emission coupled with HIFI CHESS multiline CO observations leads to the conclusion that the observed N 2 H + (1-0) line originated from the dense (≥10 5 cm –3 ) gas associated with the large (20''-25'') cavities opened by the protostellar wind. We find an N 2 H + column density of a few 10 12 cm –2 corresponding to an abundance of (2-8) × 10 –9 . The N 2 H + abundance can be matched by a model of quiescent gas evolved for more than 10 4 yr, i.e., for more than the shock kinematical age (≅2000 yr). Modeling of C-shocks confirms that the abundance of N 2 H + is not increased by the passage of the shock. In summary, N 2 H + is a fossil record of the pre-shock gas, formed when the density of the gas was around 10 4 cm –3 , and then further compressed and accelerated by the shock

Studying the outflow-core interaction with ALMA Cycle 1 observations of the HH 46/47 molecular outflow

Science.gov (United States)

Zhang, Yichen; Arce, Hector G.; Mardones, Diego; Dunham, Michael; Garay, Guido; Noriega-Crespo, Alberto; Corder, Stuartt; Offner, Stella; Cabrit, Sylvie

2016-01-01

We present ALMA Cycle 1 observations of the HH 46/47 molecular outflow which is driven by a low-mass Class 0/I protostar. Previous ALMA Cycle 0 12CO observation showed outflow cavities produced by the entrainment of ambient gas by the protostellar jet and wide-angle wind. Here we present analysis of observation of 12CO, 13CO, C18O and other species using combined 12m array and ACA observations. The improved angular resolution and sensitivity allow us to detect details of the outflow structure. Specially, we see that the outflow cavity wall is composed of two or more layers of outflowing gas, which separately connect to different shocked regions along the outflow axis inside the cavity, suggesting the outflow cavity wall is composed of multiple shells entrained by a series of jet bow-shock events. The new 13CO and C18O data also allow us to trace relatively denser and slower outflow material than that traced by the 12CO. These species are only detected within about 1 to 2 km/s from the cloud velocity, tracing the outflow to lower velocities than what is possible using only the 12CO emission. Interestingly, the cavity wall of the red lobe appears at very low outflow velocities (as low as ~0.2 km/s). In addition, 13CO and C18O allow us to correct for the CO optical depth, allowing us to obtain more accurate estimates of the outflow mass, momentum and kinetic energy. Applying the optical depth correction significantly increases the previous mass estimate by a factor of 14. The outflow kinetic energy distribution shows that even though the red lobe is mainly entrained by jet bow-shocks, most of the outflow energy is being deposited into the cloud at the base of the outflow cavity rather than around the heads of the bow shocks. The estimated total mass, momentum, and energy of the outflow indicate that the outflow has the ability to disperse the parent core. We found possible evidence for a slowly moving rotating outflow in CS. Our 13CO and C18O observations also trace a

HERSCHEL OBSERVATIONS AND UPDATED SPECTRAL ENERGY DISTRIBUTIONS OF FIVE SUNLIKE STARS WITH DEBRIS DISKS

International Nuclear Information System (INIS)

Dodson-Robinson, Sarah E.; Su, Kate Y. L.; Bryden, Geoff; Harvey, Paul; Green, Joel D.

2016-01-01

Observations from the Herschel Space Observatory have more than doubled the number of wide debris disks orbiting Sunlike stars to include over 30 systems with R  > 100 AU. Here, we present new Herschel PACS and reanalyzed Spitzer MIPS photometry of five Sunlike stars with wide debris disks, from Kuiper Belt size to R  > 150 AU. The disk surrounding HD 105211 is well resolved, with an angular extent of >14″ along the major axis, and the disks of HD 33636, HD 50554, and HD 52265 are extended beyond the PACS point-spread function size (50% of energy enclosed within radius 4.″23). HD 105211 also has a 24 μ m infrared excess, which was previously overlooked, because of a poorly constrained photospheric model. Archival Spitzer IRS observations indicate that the disks have small grains of minimum radius a min  ∼ 3 μ m, although a min is larger than the radiation-pressure blowout size in all systems. If modeled as single-temperature blackbodies, the disk temperatures would all be <60 K. Our radiative transfer models predict actual disk radii approximately twice the radius of a model blackbody disk. We find that the Herschel photometry traces dust near the source population of planetesimals. The disk luminosities are in the range 2 × 10 −5  ⩽  L / L ⊙  ⩽ 2 × 10 −4 , consistent with collisions in icy planetesimal belts stirred by Pluto-size dwarf planets.

HERSCHEL OBSERVATIONS AND UPDATED SPECTRAL ENERGY DISTRIBUTIONS OF FIVE SUNLIKE STARS WITH DEBRIS DISKS

Energy Technology Data Exchange (ETDEWEB)

Dodson-Robinson, Sarah E. [Department of Physics and Astronomy, University of Delaware, 217 Sharp Lab, Newark, DE 19716 (United States); Su, Kate Y. L. [Steward Observatory, Department of Astronomy, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Bryden, Geoff [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Harvey, Paul; Green, Joel D., E-mail: sdr@udel.edu [Astronomy Department, University of Texas, 2515 Speedway Drive C1400, Austin, TX 78712 (United States)

2016-12-20

Observations from the Herschel Space Observatory have more than doubled the number of wide debris disks orbiting Sunlike stars to include over 30 systems with R  > 100 AU. Here, we present new Herschel PACS and reanalyzed Spitzer MIPS photometry of five Sunlike stars with wide debris disks, from Kuiper Belt size to R  > 150 AU. The disk surrounding HD 105211 is well resolved, with an angular extent of >14″ along the major axis, and the disks of HD 33636, HD 50554, and HD 52265 are extended beyond the PACS point-spread function size (50% of energy enclosed within radius 4.″23). HD 105211 also has a 24 μ m infrared excess, which was previously overlooked, because of a poorly constrained photospheric model. Archival Spitzer IRS observations indicate that the disks have small grains of minimum radius a {sub min} ∼ 3 μ m, although a {sub min} is larger than the radiation-pressure blowout size in all systems. If modeled as single-temperature blackbodies, the disk temperatures would all be <60 K. Our radiative transfer models predict actual disk radii approximately twice the radius of a model blackbody disk. We find that the Herschel photometry traces dust near the source population of planetesimals. The disk luminosities are in the range 2 × 10{sup −5} ⩽  L / L {sub ⊙} ⩽ 2 × 10{sup −4}, consistent with collisions in icy planetesimal belts stirred by Pluto-size dwarf planets.

Depletion of chlorine into HCl ice in a protostellar core. The CHESS spectral survey of OMC-2 FIR 4

Science.gov (United States)

Kama, M.; Caux, E.; López-Sepulcre, A.; Wakelam, V.; Dominik, C.; Ceccarelli, C.; Lanza, M.; Lique, F.; Ochsendorf, B. B.; Lis, D. C.; Caballero, R. N.; Tielens, A. G. G. M.

2015-02-01

Context. The freezeout of gas-phase species onto cold dust grains can drastically alter the chemistry and the heating-cooling balance of protostellar material. In contrast to well-known species such as carbon monoxide (CO), the freezeout of various carriers of elements with abundances <10-5 has not yet been well studied. Aims: Our aim here is to study the depletion of chlorine in the protostellar core, OMC-2 FIR 4. Methods: We observed transitions of HCl and H2Cl+ towards OMC-2 FIR 4 using the Herschel Space Observatory and Caltech Submillimeter Observatory facilities. Our analysis makes use of state of the art chlorine gas-grain chemical models and newly calculated HCl-H2 hyperfine collisional excitation rate coefficients. Results: A narrow emission component in the HCl lines traces the extended envelope, and a broad one traces a more compact central region. The gas-phase HCl abundance in FIR 4 is 9 × 10-11, a factor of only 10-3 that of volatile elemental chlorine. The H2Cl+ lines are detected in absorption and trace a tenuous foreground cloud, where we find no depletion of volatile chlorine. Conclusions: Gas-phase HCl is the tip of the chlorine iceberg in protostellar cores. Using a gas-grain chemical model, we show that the hydrogenation of atomic chlorine on grain surfaces in the dark cloud stage sequesters at least 90% of the volatile chlorine into HCl ice, where it remains in the protostellar stage. About 10% of chlorine is in gaseous atomic form. Gas-phase HCl is a minor, but diagnostically key reservoir, with an abundance of ≲10-10 in most of the protostellar core. We find the [35Cl]/[37Cl] ratio in OMC-2 FIR 4 to be 3.2 ± 0.1, consistent with the solar system value. Appendices are available in electronic form at http://www.aanda.org

The SOFIA Massive (SOMA) Star Formation Survey. I. Overview and First Results

Energy Technology Data Exchange (ETDEWEB)

De Buizer, James M.; Shuping, Ralph [SOFIA-USRA, NASA Ames Research Center, MS 232-12, Moffett Field, CA 94035 (United States); Liu, Mengyao; Tan, Jonathan C.; Staff, Jan E.; Tanaka, Kei E. I. [Department of Astronomy, University of Florida, Gainesville, FL 32611 (United States); Zhang, Yichen [Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile); Beltrán, Maria T. [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy); Whitney, Barbara [Department of Astronomy, University of Wisconsin-Madison, 475 N. Charter St, Madison, WI 53706 (United States)

2017-07-01

We present an overview and first results of the Stratospheric Observatory For Infrared Astronomy Massive (SOMA) Star Formation Survey, which is using the FORCAST instrument to image massive protostars from ∼10 to 40 μ m. These wavelengths trace thermal emission from warm dust, which in Core Accretion models mainly emerges from the inner regions of protostellar outflow cavities. Dust in dense core envelopes also imprints characteristic extinction patterns at these wavelengths, causing intensity peaks to shift along the outflow axis and profiles to become more symmetric at longer wavelengths. We present observational results for the first eight protostars in the survey, i.e., multiwavelength images, including some ancillary ground-based mid-infrared (MIR) observations and archival Spitzer and Herschel data. These images generally show extended MIR/FIR emission along directions consistent with those of known outflows and with shorter wavelength peak flux positions displaced from the protostar along the blueshifted, near-facing sides, thus confirming qualitative predictions of Core Accretion models. We then compile spectral energy distributions and use these to derive protostellar properties by fitting theoretical radiative transfer models. Zhang and Tan models, based on the Turbulent Core Model of McKee and Tan, imply the sources have protostellar masses m {sub *} ∼ 10–50 M {sub ⊙} accreting at ∼10{sup −4}–10{sup −3} M {sub ⊙} yr{sup −1} inside cores of initial masses M {sub c} ∼ 30–500 M {sub ⊙} embedded in clumps with mass surface densities Σ{sub cl} ∼ 0.1–3 g cm{sup −2}. Fitting the Robitaille et al. models typically leads to slightly higher protostellar masses, but with disk accretion rates ∼100× smaller. We discuss reasons for these differences and overall implications of these first survey results for massive star formation theories.

Warm gas towards young stellar objects in Corona Australis

DEFF Research Database (Denmark)

Lindberg, Johan; Jørgensen, Jes Kristian; D. Green, Joel

2014-01-01

The effects of external irradiation on the chemistry and physics in the protostellar envelope around low-mass young stellar objects are poorly understood. The Corona Australis star-forming region contains the R CrA dark cloud, comprising several low-mass protostellar cores irradiated by an interm......The effects of external irradiation on the chemistry and physics in the protostellar envelope around low-mass young stellar objects are poorly understood. The Corona Australis star-forming region contains the R CrA dark cloud, comprising several low-mass protostellar cores irradiated...... by an intermediate-mass young star. We study the effects on the warm gas and dust in a group of low-mass young stellar objects from the irradiation by the young luminous Herbig Be star R CrA. Herschel/PACS far-infrared datacubes of two low-mass star-forming regions in the R CrA dark cloud are presented...... Be star R CrA. Our results show that a nearby luminous star does not increase the molecular excitation temperatures in the warm gas around a young stellar object (YSO). However, the emission from photodissociation products of H2O, such as OH and O, is enhanced in the warm gas associated...

A PHOTON-DOMINATED REGION MODEL FOR THE FIR MID-J CO LADDER WITH UNIVERSAL ROTATIONAL TEMPERATURE IN STAR FORMING REGIONS

Energy Technology Data Exchange (ETDEWEB)

Lee, Seokho; Park, Yong-Sun [Astronomy Program, Department of Physics and Astronomy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742 (Korea, Republic of); Lee, Jeong-Eun [Department of Astronomy and Space Science, Kyung Hee University, Yongin-shi, Kyungki-do 449-701 (Korea, Republic of); Bergin, Edwin A., E-mail: shlee@astro.snu.ac.kr [Department of Astronomy, University of Michigan, 830 Dennison Building, 500 Church Street, Ann Arbor, MI 48109 (United States)

2014-08-01

A photon-dominated region (PDR) is one of the leading candidate mechanisms for the origin of warm CO gas with near universal ∼300 K rotational temperature inferred from the CO emission detected toward embedded protostars by Herschel/PACS. We have developed a PDR model in general coordinates, where we can use the most adequate coordinate system for an embedded protostar having outflow cavity walls, to solve chemistry and gas energetics self-consistently for given UV radiation fields with different spectral shapes. Simple one-dimensional tests and applications show that FIR mid-J (14 ≤ J ≤ 24) CO lines are emitted from close to the surface of a dense region exposed to high UV fluxes. We apply our model to HH46 and find that the UV-heated outflow cavity wall can reproduce the mid-J CO transitions observed by Herschel/PACS. A model with UV radiation corresponding to a blackbody of 10,000 K results in a rotational temperature lower than 300 K, while models with the Draine interstellar radiation field and the 15,000 K blackbody radiation field predict a rotational temperature similar to the observed one.

A 100 au Wide Bipolar Rotating Shell Emanating from the HH 212 Protostellar Disk: A Disk Wind?

Science.gov (United States)

Lee, Chin-Fei; Li, Zhi-Yun; Codella, Claudio; Ho, Paul T. P.; Podio, Linda; Hirano, Naomi; Shang, Hsien; Turner, Neal J.; Zhang, Qizhou

2018-03-01

HH 212 is a Class 0 protostellar system found to host a “hamburger”-shaped dusty disk with a rotating disk atmosphere and a collimated SiO jet at a distance of ∼400 pc. Recently, a compact rotating outflow has been detected in SO and SO2 toward the center along the jet axis at ∼52 au (0.″13) resolution. Here we resolve the compact outflow into a small-scale wide-opening rotating outflow shell and a collimated jet, with the observations in the same S-bearing molecules at ∼16 au (0.″04) resolution. The collimated jet is aligned with the SiO jet, tracing the shock interactions in the jet. The wide-opening outflow shell is seen extending out from the inner disk around the SiO jet and has a width of ∼100 au. It is not only expanding away from the center, but also rotating around the jet axis. The specific angular momentum of the outflow shell is ∼40 au km s‑1. Simple modeling of the observed kinematics suggests that the rotating outflow shell can trace either a disk wind or disk material pushed away by an unseen wind from the inner disk or protostar. We also resolve the disk atmosphere in the same S-bearing molecules, confirming the Keplerian rotation there.

Analysis of the Herschel/Hexos Spectral Survey Toward Orion South: A Massive Protostellar Envelope with Strong External Irradiation

NARCIS (Netherlands)

Tahani, K.; Plume, R.; Bergin, E. A.; Tolls, V.; Phillips, T. G.; Caux, E.; Cabrit, S.; Goicoechea, J. R.; Goldsmith, P. F.; Johnstone, D.; Lis, D. C.; Pagani, L.; Menten, K. M.; Müller, H. S. P.; Ossenkopf-Okada, V.; Pearson, J. C.; van der Tak, F. F. S.

2016-01-01

We present results from a comprehensive submillimeter spectral survey toward the source Orion South, based on data obtained with the Heterodyne Instrument for the Far-Infrared instrument on board the Herschel Space Observatory, covering the frequency range of 480 to 1900 GHz. We detect 685 spectral

Protostellar Jets in Context

CERN Document Server

Tsinganos, Kanaris; Stute, Matthias

2009-01-01

This volume contains the proceedings of the Conference Protostellar Jets in Context held by the JETSET Marie Curie Research Training Network in July 2008. This meeting not only served to showcase some of the network's achievements but was also a platform to hear from, discuss and debate the recent findings of world-class astrophysicists in the field of protostellar jet research. Jets from young stars are of course not an isolated astrophysical phenomenon. It is known that objects as diverse as young brown dwarfs, planetary nebulae, symbiotic stars, micro-quasars, AGN, and gamma-ray bursters produce jets. Thus in a series of talks, protostellar jets were put in context by comparing them with their often much larger brethren and also by considering the ubiquitous accretion disks that seem to be necessary for their formation. With this spectrum of contributions on observations and the theory of astrophysical jets and accretion disks, this book serves as a comprehensive reference work for researchers and students...

The complete far-infrared and submillimeter spectrum of the Class 0 protostar Serpens SMM1 obtained with Herschel

DEFF Research Database (Denmark)

R. Goicoechea, Javier; Cernicharo, J.; Karska, A.

2012-01-01

We present the first complete 55-671 um spectral scan of a low-mass Class 0 protostar (Serpens SMM1) taken with the PACS and SPIRE spectrometers on board Herschel. More than 145 lines have been detected, most of them rotationally excited lines of 12CO (full ladder from J=4-3 to 42-41), H2O, OH, 13...

BROAD N{sub 2}H{sup +} EMISSION TOWARD THE PROTOSTELLAR SHOCK L1157-B1

Energy Technology Data Exchange (ETDEWEB)

Codella, C.; Fontani, F.; Gómez-Ruiz, A.; Vasta, M. [INAF, Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, I-50125 Firenze (Italy); Viti, S. [Department of Physics and Astronomy, University College London, London (United Kingdom); Ceccarelli, C.; Lefloch, B.; Podio, L. [UJF-Grenoble 1/CNRS-INSU, Institut de Planétologie et d' Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble, F-38041 (France); Benedettini, M.; Busquet, G. [INAF, Istituto di Astrofisica e Planetologia Spaziali, via Fosso del Cavaliere 100, 00133 Roma (Italy); Caselli, P., E-mail: codella@rcetri.astro.it [School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT (United Kingdom)

2013-10-10

We present the first detection of N{sub 2}H{sup +} toward a low-mass protostellar outflow, namely, the L1157-B1 shock, at ∼0.1 pc from the protostellar cocoon. The detection was obtained with the IRAM 30 m antenna. We observed emission at 93 GHz due to the J = 1-0 hyperfine lines. Analysis of this emission coupled with HIFI CHESS multiline CO observations leads to the conclusion that the observed N{sub 2}H{sup +}(1-0) line originated from the dense (≥10{sup 5} cm{sup –3}) gas associated with the large (20''-25'') cavities opened by the protostellar wind. We find an N{sub 2}H{sup +} column density of a few 10{sup 12} cm{sup –2} corresponding to an abundance of (2-8) × 10{sup –9}. The N{sub 2}H{sup +} abundance can be matched by a model of quiescent gas evolved for more than 10{sup 4} yr, i.e., for more than the shock kinematical age (≅2000 yr). Modeling of C-shocks confirms that the abundance of N{sub 2}H{sup +} is not increased by the passage of the shock. In summary, N{sub 2}H{sup +} is a fossil record of the pre-shock gas, formed when the density of the gas was around 10{sup 4} cm{sup –3}, and then further compressed and accelerated by the shock.

OT2_smalhotr_3: Herschel Extreme Lensing Line Observations (HELLO)

Science.gov (United States)

Malhotra, S.

2011-09-01

We request 59.8 hours of Herschel time to observe 20 normal star-forming galaxies in the [CII] 158 micron and [OI] 63 micron lines. These galaxies lie at high redshift (1Herschel offers the unique opportunity to study both lines with high sensitivity throughout this epoch (using HIFI for [CII] and PACS for [OI]). These two lines are the main cooling lines of the atomic medium. By measuring their fluxes, we will measure (1) the cooling efficiency of gas, (2) gas densities and temperatures near starforming regions, and (3) gas pressures, which are important to drive the winds that provide feedback to starformation processes. By combining the proposed observations with existing multiwavelength data on these objects, we will obtain as complete a picture of galaxy-scale star formation and ISM physical conditions at high redshifts as we have at z=0. Then perhaps we can understand why star formation and AGN activity peaked at this epoch. In Herschel cycle OT1, 49 high redshift IR luminous galaxies were approved for spectroscopy, but only two so-called normal galaxies were included. This is an imbalance that should be corrected, to balance Herschel's legacy.

CLASSICAL T TAURI-LIKE OUTFLOW ACTIVITY IN THE BROWN DWARF MASS REGIME

International Nuclear Information System (INIS)

Whelan, E. T.; Ray, T. P.; Podio, L.; Bacciotti, F.; Randich, S.

2009-01-01

Over the last number of years, spectroscopic studies have strongly supported the assertion that protostellar accretion and outflow activity persist to the lowest masses. Indeed, previous to this work, the existence of three brown dwarf (BD) outflows had been confirmed by us. In this paper, we present the results of our latest investigation of BD outflow activity and report on the discovery of two new outflows. Observations to date have concentrated on studying the forbidden emission line (FEL) regions of young BDs and in all cases data have been collected using the UV-Visual Echelle Spectrometer (UVES) on the ESO Very Large Telescope. Offsets in the FEL regions are recovered using spectro-astrometry. Here, ISO-Oph 32 is shown to drive a blueshifted outflow with a radial velocity of 10-20 km s -1 and spectro-astrometric analysis constrains the position angle of this outflow to 240 0 ± 7 0 . The BD candidate, ISO-ChaI 217 is found to have a bipolar outflow bright in several key forbidden lines (V RAD = -20 km s -1 , +40 km s -1 ) and with a P.A. of 193 0 -209 0 . A striking feature of the ISO-ChaI 217 outflow is the strong asymmetry between the red- and blueshifted lobes. This asymmetry is revealed in the relative brightness of the two lobes (redshifted lobe is brighter), the factor of 2 difference in radial velocity (the redshifted lobe is faster) and the difference in the electron density (again higher in the red lobe). Such asymmetries are common in jets from low-mass protostars and the observation of a marked asymmetry at such a low mass ( sun ) supports the idea that BD outflow activity is scaled down from low-mass protostellar activity. Also note that although asymmetries are unexceptional, it is uncommon for the redshifted lobe to be the brightest as some obscuration by the accretion disk is assumed. This phenomenon has only been observed in one other source, the classical T Tauri (CTTS) star RW Aur. The physical mechanism responsible for the brightening of

Modeling jet and outflow feedback during star cluster formation

Energy Technology Data Exchange (ETDEWEB)

Federrath, Christoph [Monash Centre for Astrophysics, School of Mathematical Sciences, Monash University, VIC 3800 (Australia); Schrön, Martin [Department of Computational Hydrosystems, Helmholtz Centre for Environmental Research-UFZ, Permoserstr. 15, D-04318 Leipzig (Germany); Banerjee, Robi [Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg (Germany); Klessen, Ralf S., E-mail: christoph.federrath@monash.edu [Universität Heidelberg, Zentrum für Astronomie, Institut für Theoretische Astrophysik, Albert-Ueberle-Strasse 2, D-69120 Heidelberg (Germany)

2014-08-01

Powerful jets and outflows are launched from the protostellar disks around newborn stars. These outflows carry enough mass and momentum to transform the structure of their parent molecular cloud and to potentially control star formation itself. Despite their importance, we have not been able to fully quantify the impact of jets and outflows during the formation of a star cluster. The main problem lies in limited computing power. We would have to resolve the magnetic jet-launching mechanism close to the protostar and at the same time follow the evolution of a parsec-size cloud for a million years. Current computer power and codes fall orders of magnitude short of achieving this. In order to overcome this problem, we implement a subgrid-scale (SGS) model for launching jets and outflows, which demonstrably converges and reproduces the mass, linear and angular momentum transfer, and the speed of real jets, with ∼1000 times lower resolution than would be required without the SGS model. We apply the new SGS model to turbulent, magnetized star cluster formation and show that jets and outflows (1) eject about one-fourth of their parent molecular clump in high-speed jets, quickly reaching distances of more than a parsec, (2) reduce the star formation rate by about a factor of two, and (3) lead to the formation of ∼1.5 times as many stars compared to the no-outflow case. Most importantly, we find that jets and outflows reduce the average star mass by a factor of ∼ three and may thus be essential for understanding the characteristic mass of the stellar initial mass function.

The Herschel ATLAS

Science.gov (United States)

Eales, S.; Dunne, L.; Clements, D.; Cooray, A.; De Zotti, G.; Dye, S.; Ivison, R.; Jarvis, M.; Lagache, G.; Maddox, S.;

A STUDY OF HEATING AND COOLING OF THE ISM IN NGC 1097 WITH HERSCHEL-PACS AND SPITZER-IRS

International Nuclear Information System (INIS)

Beirão, P.; Armus, L.; Helou, G.; Appleton, P. N.; Smith, J.-D. T.; Croxall, K. V.; Murphy, E. J.; Dale, D. A.; Draine, B. T.; Aniano, G.; Wolfire, M. G.; Bolatto, A. D.; Sandstrom, K. M.; Groves, B.; Schinnerer, E.; Rix, H.-W.; Brandl, B. R.; Crocker, A. F.; Hinz, J. L.; Kennicutt, R. C.

2012-01-01

NGC 1097 is a nearby Seyfert 1 galaxy with a bright circumnuclear starburst ring, a strong large-scale bar, and an active nucleus. We present a detailed study of the spatial variation of the far-infrared (FIR) [C II]158 μm and [O I]63 μm lines and mid-infrared H 2 emission lines as tracers of gas cooling, and of the polycyclic aromatic hydrocarbon (PAH) bands as tracers of the photoelectric heating, using Herschel-PACS and Spitzer-IRS infrared spectral maps. We focus on the nucleus and the ring, and two star-forming regions (Enuc N and Enuc S). We estimated a photoelectric gas heating efficiency ([C II]158 μm+[O I]63 μm)/PAH in the ring about 50% lower than in Enuc N and S. The average 11.3/7.7 μm PAH ratio is also lower in the ring, which may suggest a larger fraction of ionized PAHs, but no clear correlation with [C II]158 μm/PAH(5.5-14 μm) is found. PAHs in the ring are responsible for a factor of two more [C II]158 μm and [O I]63 μm emission per unit mass than PAHs in the Enuc S. spectral energy distribution (SED) modeling indicates that at most 25% of the FIR power in the ring and Enuc S can come from high-intensity photodissociation regions (PDRs), in which case G 0 ∼ 10 2.3 and n H ∼ 10 3.5 cm –3 in the ring. For these values of G 0 and n H , PDR models cannot reproduce the observed H 2 emission. Much of the H 2 emission in the starburst ring could come from warm regions in the diffuse interstellar medium that are heated by turbulent dissipation or shocks.

DIVERSE PROTOSTELLAR EVOLUTIONARY STATES IN THE YOUNG CLUSTER AFGL961

International Nuclear Information System (INIS)

Williams, Jonathan P.; Mann, Rita K.; Beaumont, Christopher N.; Swift, Jonathan J.; Adams, Joseph D.; Hora, Joe; Kassis, Marc; Lada, Elizabeth A.; Roman-Zuniga, Carlos G.

2009-01-01

We present arcsecond resolution mid-infrared and millimeter observations of the center of the young stellar cluster AFGL961 in the Rosette molecular cloud. Within 0.2 pc of each other, we find an early B star embedded in a dense core, a neighboring star of similar luminosity with no millimeter counterpart, a protostar that has cleared out a cavity in the circumcluster envelope, and two massive, dense cores with no infrared counterparts. An outflow emanates from one of these cores, indicating a deeply embedded protostar, but the other is starless, bound, and appears to be collapsing. The diversity of states implies either that protostellar evolution is faster in clusters than in isolation or that clusters form via quasi-static rather than dynamic collapse. The existence of a pre-stellar core at the cluster center shows that some star formation continues after and in close proximity to massive, ionizing stars.

A Herschel-Resolved Debris Disk Around the Nearby G Star HIP 32480

Science.gov (United States)

Stapelfeldt, K.

2011-01-01

The Herschel Space Observatory is providing unprecedented sensitivity and angular resolution in the far-infrared. The DUNES Key Project (DUst around NEarby Stars, PI Carlos Eiroa) has finished its survey of 133 FGK stars within 25 pc of the Sun using the PACS photometer at 100 and 160 microns. We report the detection of a resolved debris ring around HIP 32480, a G0 star 16.5 parsecs distant. The ring is almost 300 AU in diameter and inclined 30 degrees from edge-on. We present a thermal emission model for the system that fits the Spitzer spectroscopy and Herschel images of the system. We find a minimum grainsize of approximately 4 microns in the main ring and a distinct warm dust population interior to it. Faint detached emission features just outside the ring may trace a separate, more distant ring in the system. The non-detection of the ring in archival HST/ACS coronagraphic images limits the dust grain albedo in the ring to be no more than 10%.

On the diversity and statistical properties of protostellar discs

Science.gov (United States)

Bate, Matthew R.

2018-04-01

We present results from the first population synthesis study of protostellar discs. We analyse the evolution and properties of a large sample of protostellar discs formed in a radiation hydrodynamical simulation of star cluster formation. Due to the chaotic nature of the star formation process, we find an enormous diversity of young protostellar discs, including misaligned discs, and discs whose orientations vary with time. Star-disc interactions truncate discs and produce multiple systems. Discs may be destroyed in dynamical encounters and/or through ram-pressure stripping, but reform by later gas accretion. We quantify the distributions of disc mass and radii for protostellar ages up to ≈105 yr. For low-mass protostars, disc masses tend to increase with both age and protostellar mass. Disc radii range from of order 10 to a few hundred au, grow in size on time-scales ≲ 104 yr, and are smaller around lower mass protostars. The radial surface density profiles of isolated protostellar discs are flatter than the minimum mass solar nebula model, typically scaling as Σ ∝ r-1. Disc to protostar mass ratios rarely exceed two, with a typical range of Md/M* = 0.1-1 to ages ≲ 104 yr and decreasing thereafter. We quantify the relative orientation angles of circumstellar discs and the orbit of bound pairs of protostars, finding a preference for alignment that strengths with decreasing separation. We also investigate how the orientations of the outer parts of discs differ from the protostellar and inner disc spins for isolated protostars and pairs.

HERSCHEL REVEALS MASSIVE COLD CLUMPS IN NGC 7538

Energy Technology Data Exchange (ETDEWEB)

Fallscheer, C.; Di Francesco, J.; Sadavoy, S. [Department of Physics and Astronomy, University of Victoria, P.O. Box 355, STN CSC, Victoria, BC V8W 3P6 (Canada); Reid, M. A. [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada); Martin, P. G.; Nguyen-Luong, Q. [Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, ON M5S 3H8 (Canada); Hill, T.; Hennemann, M.; Motte, F.; Men' shchikov, A.; Andre, Ph.; Konyves, V.; Sauvage, M. [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, IRFU/Service d' Astrophysique, Saclay, F-91191 Gif-sur-Yvette (France); Ward-Thompson, D.; Kirk, J. [Jeremiah Horrocks Institute, University of Central Lancashire, Preston, Lancashire, PR1 2HE (United Kingdom); Griffin, M. [School of Physics and Astronomy, Cardiff University, Queen' s Buildings, The Parade, Cardiff CF24 3AA (United Kingdom); Rygl, K. L. J.; Benedettini, M. [INAF, Istituto di Astrofisica e Planetologia Spaziali, Area di Ricerca di Tor Vergata, via Fosso del Cavaliere 100, I-00133 Roma (Italy); Schneider, N. [Universite de Bordeaux, LAB, UMR 5804, F-33270, Floirac (France); Anderson, L. D. [Laboratoire d' Astrophysique de Marseille, CNRS/INSU, Universite de Provence, F-13388 Marseille Cedex 13 (France); and others

2013-08-20

We present the first overview of the Herschel observations of the nearby high-mass star-forming region NGC 7538, taken as part of the Herschel imaging study of OB young stellar objects (HOBYS) Key Programme. These PACS and SPIRE maps cover an approximate area of one square degree at five submillimeter and far-infrared wavebands. We have identified 780 dense sources and classified 224 of those. With the intention of investigating the existence of cold massive starless or class 0-like clumps that would have the potential to form intermediate- to high-mass stars, we further isolate 13 clumps as the most likely candidates for follow-up studies. These 13 clumps have masses in excess of 40 M{sub Sun} and temperatures below 15 K. They range in size from 0.4 pc to 2.5 pc and have densities between 3 Multiplication-Sign 10{sup 3} cm{sup -3} and 4 Multiplication-Sign 10{sup 4} cm{sup -3}. Spectral energy distributions are then used to characterize their energetics and evolutionary state through a luminosity-mass diagram. NGC 7538 has a highly filamentary structure, previously unseen in the dust continuum of existing submillimeter surveys. We report the most complete imaging to date of a large, evacuated ring of material in NGC 7538 which is bordered by many cool sources.

ROTATION AND OUTFLOW MOTIONS IN THE VERY LOW-MASS CLASS 0 PROTOSTELLAR SYSTEM HH 211 AT SUBARCSECOND RESOLUTION

International Nuclear Information System (INIS)

Lee, C.-F.; Hirano, Naomi; Ho, Paul T. P.; Shang, Hsien; Palau, Aina; Bourke, Tyler L.; Zhang Qizhou

2009-01-01

HH 211 is a nearby young protostellar system with a highly collimated jet. We have mapped it in 352 GHz continuum, SiO (J = 8 - 7), and HCO + (J = 4 - 3) emission at up to ∼0.''2 resolution with the Submillimeter Array (SMA). The continuum source is now resolved into two sources, SMM1 and SMM2, with a separation of ∼ 84 AU. SMM1 is seen at the center of the jet, probably tracing a (inner) dusty disk around the protostar driving the jet. SMM2 is seen to the southwest of SMM1 and may trace an envelope-disk around a small binary companion. A flattened envelope-disk is seen in HCO + around SMM1 with a radius of ∼ 80 AU perpendicular to the jet axis. Its velocity structure is consistent with a rotation motion and can be fitted with a Keplerian law that yields a mass of ∼50 ± 15 M Jup (a mass of a brown dwarf) for the protostar. Thus, the protostar could be the lowest mass source known to have a collimated jet and a rotating flattened envelope-disk. A small-scale (∼200 AU) low-speed (∼2 km s -1 ) outflow is seen in HCO + around the jet axis extending from the envelope-disk. It seems to rotate in the same direction as the envelope-disk and may carry away part of the angular momentum from the envelope-disk. The jet is seen in SiO close to ∼100 AU from SMM1. It is seen with a 'C-shaped' bending. It has a transverse width of ∼ -1 . A possible velocity gradient is seen consistently across its innermost pair of knots, ∼0.5 km s -1 at ∼10 AU, consistent with the sense of rotation of the envelope-disk. If this gradient is an upper limit of the true rotational gradient of the jet, then the jet carries away a very small amount of angular momentum of ∼ -1 and thus must be launched from the very inner edge of the disk near the corotation radius.

ON THE ORIGIN OF THE MOLECULAR OUTFLOWS IN IRAS 16293–2422

Energy Technology Data Exchange (ETDEWEB)

Girart, Josep M.; Palau, Aina; Torrelles, José M. [Institut de Ciències de l' Espai, (CSIC-IEEC), Campus UAB, Facultat de Ciències, C5p 2, E-08193 Bellaterra, Catalonia (Spain); Estalella, Robert [Departament d' Astronomia i Meteorologia, Institut de Ciències del Cosmos (UB-IEEC), Martí i Franquès, Universitat de Barcelona, E-08028 Barcelona, Catalonia (Spain); Rao, Ramprasad, E-mail: girart@ice.cat [Institute of Astronomy and Astrophysics, Academia Sinica, 645 N. Aohoku Pl., Hilo, HI 96720 (United States)

2014-01-01

We present CO 3-2, SiO 8-7, C{sup 34}S 7-6, and 878 μm dust continuum subarcsecond angular resolution observations with the Submillimeter Array (SMA) toward the IRAS 16293–2422 (I16293) multiple low-mass protostellar system. The C{sup 34}S emission traces the 878 μm dust continuum well, and in addition clearly shows a smooth velocity gradient along the major axis of component I16293A. CO shows emission at moderate high velocities arising from two bipolar outflows, which appear to be perpendicular with respect to each other. The high sensitivity and higher angular resolution of these observations allows us to pinpoint well the origin of these two outflows at the center of component I16293A. Interestingly, the most compact outflow appears to point toward I16293B. Our data show that the previously reported monopolar blueshifted CO outflow associated with component I16293B seems to be part of the compact outflow arising from component I16293A. In addition, the SiO emission is also tracing this compact outflow: on the one hand, the SiO emission appears to have a jet-like morphology along the southern redshifted lobe; on the other hand, the SiO emission associated with the blueshifted northern lobe traces a well-defined arc on the border of component I16293B facing I16293A. The blueshifted CO lobe of the compact outflow splits into two lobes around the position of this SiO arc. All these results lead us to propose that the compact outflow from component I16293A is impacting on the circumstellar gas around component I16293B, possibly being diverged as a consequence of the interaction.

Uncovering the Protostars in Serpens South with ALMA: Continuum Sources and Their Outflow Activity

Science.gov (United States)

Plunkett, Adele; Arce, H.; Corder, S.; Dunham, M.

2017-06-01

Serpens South is an appealing protostellar cluster to study due the combination of several factors: (1) a high protostar fraction that shows evidence for very recent and ongoing star formation; (2) iconic clustered star formation along a filamentary structure; (3) its relative proximity within a few hundred parsecs. An effective study requires the sensitivity, angular and spectral resolution, and mapping capabilities recently provided with ALMA. Here we present a multi-faceted data set acquired from Cycles 1 through 3 with ALMA, including maps of continuum sources and molecular outflows throughout the region, as well as a more focused kinematical study of the protostar that is the strongest continuum source at the cluster center. Together these data span spatial scales over several orders of magnitude, allowing us to investigate the outflow-driving sources and the impact of the outflows on the cluster environment. Currently, we focus on the census of protostars in the cluster center, numbering about 20, including low-flux, low-mass sources never before detected in mm-wavelengths and evidence for multiplicity that was previously unresolved.

A young bipolar outflow from IRAS 15398-3359

Science.gov (United States)

Bjerkeli, P.; Jørgensen, J. K.; Brinch, C.

2016-03-01

Context. Changing physical conditions in the vicinity of protostars allow for a rich and interesting chemistry to occur. Heating and cooling of the gas allows molecules to be released from and frozen out on dust grains. These changes in physics, traced by chemistry as well as the kinematical information, allows us to distinguish between different scenarios describing the infall of matter and the launching of molecular outflows and jets. Aims: We aim to determine the spatial distribution of different species that are of different chemical origin. This is to examine the physical processes in play in the observed region. From the kinematical information of the emission lines we aim to determine the nature of the infalling and outflowing gas in the system. We also aim to determine the physical properties of the outflow. Methods: Maps from the Submillimeter Array (SMA) reveal the spatial distribution of the gaseous emission towards IRAS 15398-3359. The line radiative transfer code LIME is used to construct a full 3D model of the system taking all relevant components and scales into account. Results: CO, HCO+, and N2H+ are detected and shown to trace the motions of the outflow. For CO, the circumstellar envelope and the surrounding cloud also have a profound impact on the observed line profiles. N2H+ is detected in the outflow, but is suppressed towards the central region, perhaps because of the competing reaction between CO and H3+ in the densest regions as well as the destruction of N2H+ by CO. N2D+ is detected in a ridge south-west of the protostellar condensation and is not associated with the outflow. The morphology and kinematics of the CO emission suggests that the source is younger than ~1000 years. The mass, momentum, momentum rate, mechanical luminosity, kinetic energy, and mass-loss rate are also all estimated to be low. A full 3D radiative transfer model of the system can explain all the kinematical and morphological features in the system.

A STUDY OF HEATING AND COOLING OF THE ISM IN NGC 1097 WITH HERSCHEL-PACS AND SPITZER-IRS

Energy Technology Data Exchange (ETDEWEB)

Beirao, P.; Armus, L. [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Helou, G. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Appleton, P. N. [NASA Herschel Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Smith, J.-D. T.; Croxall, K. V. [Department of Physics and Astronomy, Mail Drop 111, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606 (United States); Murphy, E. J. [Carnegie Observatories, Pasadena, CA 91101 (United States); Dale, D. A. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Draine, B. T.; Aniano, G. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Wolfire, M. G.; Bolatto, A. D. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Sandstrom, K. M.; Groves, B.; Schinnerer, E.; Rix, H.-W. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, 69117 Heidelberg (Germany); Brandl, B. R. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Crocker, A. F. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Hinz, J. L. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Kennicutt, R. C., E-mail: pedro@ipac.caltech.edu [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); and others

2012-06-01

NGC 1097 is a nearby Seyfert 1 galaxy with a bright circumnuclear starburst ring, a strong large-scale bar, and an active nucleus. We present a detailed study of the spatial variation of the far-infrared (FIR) [C II]158 {mu}m and [O I]63 {mu}m lines and mid-infrared H{sub 2} emission lines as tracers of gas cooling, and of the polycyclic aromatic hydrocarbon (PAH) bands as tracers of the photoelectric heating, using Herschel-PACS and Spitzer-IRS infrared spectral maps. We focus on the nucleus and the ring, and two star-forming regions (Enuc N and Enuc S). We estimated a photoelectric gas heating efficiency ([C II]158 {mu}m+[O I]63 {mu}m)/PAH in the ring about 50% lower than in Enuc N and S. The average 11.3/7.7 {mu}m PAH ratio is also lower in the ring, which may suggest a larger fraction of ionized PAHs, but no clear correlation with [C II]158 {mu}m/PAH(5.5-14 {mu}m) is found. PAHs in the ring are responsible for a factor of two more [C II]158 {mu}m and [O I]63 {mu}m emission per unit mass than PAHs in the Enuc S. spectral energy distribution (SED) modeling indicates that at most 25% of the FIR power in the ring and Enuc S can come from high-intensity photodissociation regions (PDRs), in which case G{sub 0} {approx} 10{sup 2.3} and n{sub H} {approx} 10{sup 3.5} cm{sup -3} in the ring. For these values of G{sub 0} and n{sub H}, PDR models cannot reproduce the observed H{sub 2} emission. Much of the H{sub 2} emission in the starburst ring could come from warm regions in the diffuse interstellar medium that are heated by turbulent dissipation or shocks.

Panchromatic spectral energy distributions of Herschel sources

Science.gov (United States)

Berta, S.; Lutz, D.; Santini, P.; Wuyts, S.; Rosario, D.; Brisbin, D.; Cooray, A.; Franceschini, A.; Gruppioni, C.; Hatziminaoglou, E.; Hwang, H. S.; Le Floc'h, E.; Magnelli, B.; Nordon, R.; Oliver, S.; Page, M. J.; Popesso, P.; Pozzetti, L.; Pozzi, F.; Riguccini, L.; Rodighiero, G.; Roseboom, I.; Scott, D.; Symeonidis, M.; Valtchanov, I.; Viero, M.; Wang, L.

2013-03-01

Combining far-infrared Herschel photometry from the PACS Evolutionary Probe (PEP) and Herschel Multi-tiered Extragalactic Survey (HerMES) guaranteed time programs with ancillary datasets in the GOODS-N, GOODS-S, and COSMOS fields, it is possible to sample the 8-500 μm spectral energy distributions (SEDs) of galaxies with at least 7-10 bands. Extending to the UV, optical, and near-infrared, the number of bands increases up to 43. We reproduce the distribution of galaxies in a carefully selected restframe ten colors space, based on this rich data-set, using a superposition of multivariate Gaussian modes. We use this model to classify galaxies and build median SEDs of each class, which are then fitted with a modified version of the magphys code that combines stellar light, emission from dust heated by stars and a possible warm dust contribution heated by an active galactic nucleus (AGN). The color distribution of galaxies in each of the considered fields can be well described with the combination of 6-9 classes, spanning a large range of far- to near-infrared luminosity ratios, as well as different strength of the AGN contribution to bolometric luminosities. The defined Gaussian grouping is used to identify rare or odd sources. The zoology of outliers includes Herschel-detected ellipticals, very blue z ~ 1 Ly-break galaxies, quiescent spirals, and torus-dominated AGN with star formation. Out of these groups and outliers, a new template library is assembled, consisting of 32 SEDs describing the intrinsic scatter in the restframe UV-to-submm colors of infrared galaxies. This library is tested against L(IR) estimates with and without Herschel data included, and compared to eightother popular methods often adopted in the literature. When implementing Herschel photometry, these approaches produce L(IR) values consistent with each other within a median absolute deviation of 10-20%, the scatter being dominated more by fine tuning of the codes, rather than by the choice of

The Herschel objects and how to observe them exploring sir William Herschel's star clusters, nebulae, and galaxies

CERN Document Server

Mullaney, James

2007-01-01

Deep-sky observers are always on the lookout for new observing challenges. "The Herschel Objects, and How to Observe them" offers an exciting opportunity to retrace the footsteps of Sir William Herschel, discoverer of Uranus and arguably the greatest visual observer and celestial explorer that ever lived!Following a biography of Herschel that details his life and the telescopes he used, this practical observer's guide lists all the most impressive of Herschel's star clusters, nebulae and galaxies.More than 600 of the brightest of the objects that Herschel observed are covered, and there are detailed descriptions and images of almost 200 of the very best Herschel objects for amateur astronomers.

FEEDBACK EFFECTS ON LOW-MASS STAR FORMATION

International Nuclear Information System (INIS)

Hansen, Charles E.; Klein, Richard I.; McKee, Christopher F.; Fisher, Robert T.

2012-01-01

Protostellar feedback, both radiation and bipolar outflows, dramatically affects the fragmentation and mass accretion from star-forming cores. We use ORION, an adaptive mesh refinement gravito-radiation-hydrodynamics code, to simulate low-mass star formation in a turbulent molecular cloud in the presence of protostellar feedback. We present results of the first simulations of a star-forming cluster that include both radiative transfer and protostellar outflows. We run four simulations to isolate the individual effects of radiation feedback and outflow feedback as well as the combination of the two. We find that outflows reduce protostellar masses and accretion rates each by a factor of three and therefore reduce protostellar luminosities by an order of magnitude. This means that, while radiation feedback suppresses fragmentation, outflows render protostellar radiation largely irrelevant for low-mass star formation above a mass scale of 0.05 M ☉ . We find initial fragmentation of our cloud at half the global Jeans length, around 0.1 pc. With insufficient protostellar radiation to stop it, these 0.1 pc cores fragment repeatedly, forming typically 10 stars each. The accretion rate in these stars scales with mass as predicted from core accretion models that include both thermal and turbulent motions; the accretion rate does not appear to be consistent with either competitive accretion or accretion from an isothermal sphere. We find that protostellar outflows do not significantly affect the overall cloud dynamics, in the absence of magnetic fields, due to their small opening angles and poor coupling to the dense gas. The outflows reduce the mass from the cores by 2/3, giving a core to star efficiency, ε core ≅ 1/3. The simulations are also able to reproduce many observation of local star-forming regions. Our simulation with radiation and outflows reproduces the observed protostellar luminosity function. All of the simulations can reproduce observed core mass

CLASS 0 PROTOSTARS IN THE PERSEUS MOLECULAR CLOUD: A CORRELATION BETWEEN THE YOUNGEST PROTOSTARS AND THE DENSE GAS DISTRIBUTION

Energy Technology Data Exchange (ETDEWEB)

Sadavoy, S. I.; Di Francesco, J. [Department of Physics and Astronomy, University of Victoria, P.O. Box 355, STN CSC, Victoria, BC, V8W 3P6 (Canada); André, Ph.; Maury, A.; Men' shchikov, A.; Motte, F.; Hennemann, M.; Könyves, V.; Louvet, F.; Roy, A. [Laboratoire AIM, CEA/DSM-CNRS-Université Paris Diderot, IRFU/Service dAstrophysique, Saclay, F-91191 Gif-sur-Yvette (France); Pezzuto, S.; Benedettini, M.; Elia, D. [Istituto di Astrofisica e Planetologia Spaziali, Via Fosso del Cavaliere 100, I-00133 Rome (Italy); Bernard, J.-P. [CNRS, IRAP, 9 Av. Colonel Roche, BP 44346, F-31028 Toulouse Cedex 4 (France); Nguyên-Lu' o' ng, Q. [Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, ON, M5S 3H8 (Canada); Schneider, N.; Bontemps, S. [Université de Bordeaux, LAB, UMR 5804, F-33270 Floirac (France); Arzoumanian, D. [IAS, CNRS (UMR 8617), Université Paris-Sud 11, Bâtiment 121, F-91400 Orsay (France); Hill, T. [Joint ALMA Observatory, Alonso de Cordova 3107, Vitacura 763-0355, Santiago (Chile); Peretto, N., E-mail: sadavoy@mpia.de [School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom); and others

2014-06-01

We use PACS and SPIRE continuum data at 160 μm, 250 μm, 350 μm, and 500 μm from the Herschel Gould Belt Survey to sample seven clumps in Perseus: B1, B1-E, B5, IC 348, L1448, L1455, and NGC 1333. Additionally, we identify and characterize the embedded Class 0 protostars using detections of compact Herschel sources at 70 μm as well as archival Spitzer catalogs and SCUBA 850 μm photometric data. We identify 28 candidate Class 0 protostars, four of which are newly discovered sources not identified with Spitzer. We find that the star formation efficiency of clumps, as traced by Class 0 protostars, correlates strongly with the flatness of their respective column density distributions at high values. This correlation suggests that the fraction of high column density material in a clump reflects only its youngest protostellar population rather than its entire source population. We propose that feedback from either the formation or evolution of protostars changes the local density structure of clumps.

A SYSTEMATIC SEARCH FOR MOLECULAR OUTFLOWS TOWARD CANDIDATE LOW-LUMINOSITY PROTOSTARS AND VERY LOW LUMINOSITY OBJECTS

Energy Technology Data Exchange (ETDEWEB)

Schwarz, Kamber R.; Shirley, Yancy L. [Steward Observatory, 933 N. Cherry Ave., Tucson, AZ 85721 (United States); Dunham, Michael M. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States)

2012-10-01

We present a systematic single-dish search for molecular outflows toward a sample of nine candidate low-luminosity protostars and 30 candidate very low luminosity objects (VeLLOs; L{sub int} {<=} 0.1 L{sub Sun }). The sources are identified using data from the Spitzer Space Telescope cataloged by Dunham et al. toward nearby (D < 400 pc) star-forming regions. Each object was observed in {sup 12}CO and {sup 13}CO J = 2 {yields} 1 simultaneously using the sideband separating ALMA Band-6 prototype receiver on the Heinrich Hertz Telescope at 30'' resolution. Using five-point grid maps, we identify five new potential outflow candidates and make on-the-fly maps of the regions surrounding sources in the dense cores B59, L1148, L1228, and L1165. Of these new outflow candidates, only the map of B59 shows a candidate blue outflow lobe associated with a source in our survey. We also present larger and more sensitive maps of the previously detected L673-7 and the L1251-A-IRS4 outflows and analyze their properties in comparison to other outflows from VeLLOs. The accretion luminosities derived from the outflow properties of the VeLLOs with detected CO outflows are higher than the observed internal luminosity of the protostars, indicating that these sources likely had higher accretion rates in the past. The known L1251-A-IRS3 outflow is detected but not re-mapped. We do not detect clear, unconfused signatures of red and blue molecular wings toward the other 31 sources in the survey indicating that large-scale, distinct outflows are rare toward this sample of candidate protostars. Several potential outflows are confused with the kinematic structure in the surrounding core and cloud. Interferometric imaging is needed to disentangle large-scale molecular cloud kinematics from these potentially weak protostellar outflows.

A SYSTEMATIC SEARCH FOR MOLECULAR OUTFLOWS TOWARD CANDIDATE LOW-LUMINOSITY PROTOSTARS AND VERY LOW LUMINOSITY OBJECTS

International Nuclear Information System (INIS)

Schwarz, Kamber R.; Shirley, Yancy L.; Dunham, Michael M.

2012-01-01

We present a systematic single-dish search for molecular outflows toward a sample of nine candidate low-luminosity protostars and 30 candidate very low luminosity objects (VeLLOs; L int ≤ 0.1 L ☉ ). The sources are identified using data from the Spitzer Space Telescope cataloged by Dunham et al. toward nearby (D 12 CO and 13 CO J = 2 → 1 simultaneously using the sideband separating ALMA Band-6 prototype receiver on the Heinrich Hertz Telescope at 30'' resolution. Using five-point grid maps, we identify five new potential outflow candidates and make on-the-fly maps of the regions surrounding sources in the dense cores B59, L1148, L1228, and L1165. Of these new outflow candidates, only the map of B59 shows a candidate blue outflow lobe associated with a source in our survey. We also present larger and more sensitive maps of the previously detected L673-7 and the L1251-A-IRS4 outflows and analyze their properties in comparison to other outflows from VeLLOs. The accretion luminosities derived from the outflow properties of the VeLLOs with detected CO outflows are higher than the observed internal luminosity of the protostars, indicating that these sources likely had higher accretion rates in the past. The known L1251-A-IRS3 outflow is detected but not re-mapped. We do not detect clear, unconfused signatures of red and blue molecular wings toward the other 31 sources in the survey indicating that large-scale, distinct outflows are rare toward this sample of candidate protostars. Several potential outflows are confused with the kinematic structure in the surrounding core and cloud. Interferometric imaging is needed to disentangle large-scale molecular cloud kinematics from these potentially weak protostellar outflows.

MHOs toward HMOs: A Search for Molecular Hydrogen Emission-Line Objects toward High-mass Outflows

Energy Technology Data Exchange (ETDEWEB)

Wolf-Chase, Grace [Astronomy Department Adler Planetarium 1300 S. Lake Shore Drive Chicago, IL 60605 (United States); Arvidsson, Kim [Trull School of Sciences and Mathematics Schreiner University 2100 Memorial Blvd. Kerrville, TX 78028 (United States); Smutko, Michael, E-mail: gwolfchase@adlerplanetarium.org [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), and Dept. of Physics and Astronomy, Northwestern University, 2131 Tech Drive, Evanston, IL 60208 (United States)

2017-07-20

We present the results of a narrow-band near-infrared imaging survey for Molecular Hydrogen emission-line Objects (MHOs) toward 26 regions containing high-mass protostellar candidates and massive molecular outflows. We have detected a total of 236 MHOs, 156 of which are new detections, in 22 out of the 26 regions. We use H{sub 2} 2.12 μ m/H{sub 2} 2.25 μ m flux ratios, together with morphology, to separate the signatures of fluorescence associated with photo-dissociation regions (PDRs) from shocks associated with outflows in order to identify the MHOs. PDRs have typical low flux ratios of ∼1.5–3, while the vast majority of MHOs display flux ratios typical of C-type shocks (∼6–20). A few MHOs exhibit flux ratios consistent with expected values for J-type shocks (∼3–4), but these are located in regions that may be contaminated with fluorescent emission. Some previously reported MHOs have low flux ratios, and are likely parts of PDRs rather than shocks indicative of outflows. We identify a total of 36 outflows across the 22 target regions where MHOs were detected. In over half these regions, MHO arrangements and fluorescent structures trace features present in CO outflow maps, suggesting that the CO emission traces a combination of dynamical effects, which may include gas entrained in expanding PDRs as well as bipolar outflows. Where possible, we link MHO complexes to distinct outflows and identify candidate driving sources.

The structure of protostellar dense cores: a millimeter continuum study

International Nuclear Information System (INIS)

Motte, Frederique

1998-01-01

A comprehensive theoretical scenario explains low-mass star formation and describes the gravitational collapse of an isolated 'ideal' dense core. The major aim of this thesis is to check the standard model predictions on the structure of protostellar dense cores (or envelopes). The earliest stages of star formation remain poorly known because the protostars are still deeply embedded in massive, opaque circumstellar cocoons. On the one hand, sensitive bolometer arrays very recently allow us to measure the millimeter continuum emission arising from dense cores. Such observations are a powerful tool to constrain the density structure of proto-stellar dense cores (on large length scale). In particular, we studied the structure of isolated proto-stellar envelopes in Taurus and protostars in the ρ Ophiuchi cluster. In order to accurately derive their envelope density power law, we simulated the observation of several envelope models. Then we show that most of the Taurus protostars present a density structure consistent with the standard model predictions. In contrast, dense cores in ρ Ophiuchi main cloud are highly fragmented and protostellar envelope have finite size. Moreover fragmentation appears to be essential in determining the final stellar mass of ρ Oph forming stars. In clusters, fragmentation may thus be at the origin of the stellar initial mass function (IMF). On the other hand, our interferometric millimeter continuum observations are tracing (with higher angular resolution) the inner part of protostellar envelopes. Our study show that disks during protostellar stages are not yet massive and thus do not perturb the analysis of envelope density structure. (author) [fr

A COOL DUST FACTORY IN THE CRAB NEBULA: A HERSCHEL STUDY OF THE FILAMENTS

Energy Technology Data Exchange (ETDEWEB)

Gomez, H. L.; Clark, C. J. R.; Gomez, E. L.; Gear, W. K. [School of Physics and Astronomy, Cardiff University, The Parade, Cardiff CF24 3AA (United Kingdom); Krause, O.; Besel, M.-A.; Bouwman, J.; Henning, Th. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Barlow, M. J.; Swinyard, B. M.; Owen, P. J.; Matsuura, M. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Rho, J. [SOFIA Science Center, Universities Space Research Association, NASA Ames Research Center, MS 232, Moffett Field, CA 94035 (United States); Ivison, R. J.; Sibthorpe, B. [UK Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Polehampton, E. T. [Space Science and Technology Department, Rutherford Appleton Laboratory, Oxfordshire, OX11 0QX (United Kingdom)

2012-11-20

Whether supernovae are major sources of dust in galaxies is a long-standing debate. We present infrared and submillimeter photometry and spectroscopy from the Herschel Space Observatory of the Crab Nebula between 51 and 670 {mu}m as part of the Mass Loss from Evolved StarS program. We compare the emission detected with Herschel with multiwavelength data including millimeter, radio, mid-infrared, and archive optical images. We carefully remove the synchrotron component using the Herschel and Planck fluxes measured in the same epoch. The contribution from line emission is removed using Herschel spectroscopy combined with Infrared Space Observatory archive data. Several forbidden lines of carbon, oxygen, and nitrogen are detected where multiple velocity components are resolved, deduced to be from the nitrogen-depleted, carbon-rich ejecta. No spectral lines are detected in the SPIRE wavebands; in the PACS bands, the line contribution is 5% and 10% at 70 and 100 {mu}m and negligible at 160 {mu}m. After subtracting the synchrotron and line emission, the remaining far-infrared continuum can be fit with two dust components. Assuming standard interstellar silicates, the mass of the cooler component is 0.24{sup +0.32} {sub -0.08} M {sub Sun} for T = 28.1{sup +5.5} {sub -3.2} K. Amorphous carbon grains require 0.11 {+-} 0.01 M {sub Sun} of dust with T = 33.8{sup +2.3} {sub -1.8} K. A single temperature modified blackbody with 0.14 M {sub Sun} and 0.08 M {sub Sun} for silicate and carbon dust, respectively, provides an adequate fit to the far-infrared region of the spectral energy distribution but is a poor fit at 24-500 {mu}m. The Crab Nebula has condensed most of the relevant refractory elements into dust, suggesting the formation of dust in core-collapse supernova ejecta is efficient.

The effects of magnetic fields and protostellar feedback on low-mass cluster formation

Science.gov (United States)

Cunningham, Andrew J.; Krumholz, Mark R.; McKee, Christopher F.; Klein, Richard I.

2018-05-01

We present a large suite of simulations of the formation of low-mass star clusters. Our simulations include an extensive set of physical processes - magnetohydrodynamics, radiative transfer, and protostellar outflows - and span a wide range of virial parameters and magnetic field strengths. Comparing the outcomes of our simulations to observations, we find that simulations remaining close to virial balance throughout their history produce star formation efficiencies and initial mass function (IMF) peaks that are stable in time and in reasonable agreement with observations. Our results indicate that small-scale dissipation effects near the protostellar surface provide a feedback loop for stabilizing the star formation efficiency. This is true regardless of whether the balance is maintained by input of energy from large-scale forcing or by strong magnetic fields that inhibit collapse. In contrast, simulations that leave virial balance and undergo runaway collapse form stars too efficiently and produce an IMF that becomes increasingly top heavy with time. In all cases, we find that the competition between magnetic flux advection towards the protostar and outward advection due to magnetic interchange instabilities, and the competition between turbulent amplification and reconnection close to newly formed protostars renders the local magnetic field structure insensitive to the strength of the large-scale field, ensuring that radiation is always more important than magnetic support in setting the fragmentation scale and thus the IMF peak mass. The statistics of multiple stellar systems are similarly insensitive to variations in the initial conditions and generally agree with observations within the range of statistical uncertainty.

VizieR Online Data Catalog: Herschel FIR observations of NGC3603 (Di Cecco+, 2015)

Science.gov (United States)

di Cecco, A.; Faustini, F.; Paresce, F.; Correnti, M.; Calzoletti, L.

2015-06-01

The cloud complex surrounding NGC 3603 YC was observed by Herschel SPIRE/PACS during the Hi-GAL Survey (Molinari et al. 2010A&A...518L.100M, 2010PASP..122..314M), a Key Programme that mapped the Galactic plane in five photometric bands (70, 160, 250, 350, and 500um). The MSX (Egan et al. 2003AAS...203.5708E) images were taken at (wavelengths) 8.3, 12.1, 14.7, and 21.3um using the scan observing mode, and the WISE (Wright et al. 2010AJ....140.1868W) images were acquired in freeze-frame scan mode at 3.4, 4.6, 12, and 22um. (2 data files).

Infrared astronomy seeing the heat : from William Herschel to the Herschel space observatory

CERN Document Server

Clements, David L

2014-01-01

Uncover the Secrets of the Universe Hidden at Wavelengths beyond Our Optical GazeWilliam Herschel's discovery of infrared light in 1800 led to the development of astronomy at wavelengths other than the optical. Infrared Astronomy - Seeing the Heat: from William Herschel to the Herschel Space Observatory explores the work in astronomy that relies on observations in the infrared. Author David L. Clements, a distinguished academic and science fiction writer, delves into how the universe works, from the planets in our own Solar System to the universe as a whole. The book first presents the major t

Water in massive star-forming regions with Herschel Space Observatory

Science.gov (United States)

Chavarria, L.; Herpin, F.; Bontemps, S.; Jacq, T.; Baudry, A.; Braine, J.; van der Tak, F.; Wyrowski, F.; van Dishoeck, E. F.

2011-05-01

High-mass stars formation process is much less understood than the low-mass case: short timescales, high opacities and long distance to the sources challenge the study of young massive stars. The instruments on board the Heschel Space Observatory permit us to investigate molecular species at high spectral resolution in the sub-milimeter wavelengths. Water, one of the most abundant molecules in the Universe, might elucidate key episodes in the process of stellar birth and it may play a major role in the formation of high-mass stars. This contribution presents the first results of the Heschel Space Observatory key-program WISH (Water In Star forming regions with Herschel) concerning high-mass protostars. The program main purpose is to follow the process of star formation during the various stages using the water molecule as a physical diagnostic throughout the evolution. In general, we aim to adress the following questions: How does protostars interact with their environment ? How and where water is formed ? How is it transported from cloud to disk ? When and where water becomes a dominant cooling or heating agent ? We use the HIFI and PACS instruments to obtain maps and spectra of ~20 water lines in ~20 massive protostars spanning a large range in physical parameters, from pre-stellar cores to UCHII regions. I will review the status of the program and focus specifically on the spectroscopic results. I will show how powerful are the HIFI high-resolution spectral observations to resolve different physical source components such as the dense core, the outflows and the extended cold cloud around the high-mass object. We derive water abundances between 10-7 and 10-9 in the outer envelope. The abundance variations derived from our models suggest that different chemical mechanisms are at work on these scales (e.g. evaporation of water-rich icy grain mantles). The detection and derived abundance ratios for rare isotopologues will be discussed. Finally, a comparison in tems

Protostellar accretion traced with chemistry

DEFF Research Database (Denmark)

Frimann, Søren; Jørgensen, Jes Kristian; Dunham, Michael M.

2017-01-01

. Our aim is to characterise protostellar accretion histories towards individual sources by utilising sublimation and freeze-out chemistry of CO. Methods. A sample of 24 embedded protostars are observed with the Submillimeter Array (SMA) in context of the large program "Mass Assembly of Stellar Systems...

A Thorough View of the Nuclear Region of NGC 253: Combined Herschel, SOFIA, and APEX Data Set

Science.gov (United States)

Pérez-Beaupuits, J. P.; Güsten, R.; Harris, A.; Requena-Torres, M. A.; Menten, K. M.; Weiß, A.; Polehampton, E.; van der Wiel, M. H. D.

2018-06-01

We present a large set of spectral lines detected in the 40″ central region of the starburst galaxy NGC 253. Observations were obtained with the three instruments SPIRE, PACS, and HIFI on board the Herschel Space Observatory, upGREAT on board the SOFIA airborne observatory, and the ground-based Atacama Pathfinder EXperiment telescope. Combining the spectral and photometry products of SPIRE and PACS, we model the dust continuum spectral energy distribution (SED) and the most complete 12CO line SED reported so far toward the nuclear region of NGC 253. The properties and excitation of the molecular gas were derived from a three-component non-LTE radiative transfer model, using the SPIRE 13CO lines and ground-based observations of the lower-J 13CO and HCN lines, to constrain the model parameters. Three dust temperatures were identified from the continuum emission, and three components are needed to fit the full CO line SED. Only the third CO component (fitting mostly the HCN and PACS 12CO lines) is consistent with a shock-/mechanical-heating scenario. A hot core chemistry is also argued as a plausible scenario to explain the high-J 12CO lines detected with PACS. The effect of enhanced cosmic-ray ionization rates, however, cannot be ruled out and is expected to play a significant role in the diffuse and dense gas chemistry. This is supported by the detection of ionic species like OH+ and H2O+, as well as the enhanced fluxes of the OH lines with respect to those of H2O lines detected in both PACS and SPIRE spectra.

Herschel/PACS observations of young sources in Taurus : The far-infrared counterpart of optical jets

NARCIS (Netherlands)

Podio, L.; Kamp, I.; Flower, D.; Howard, C.; Sandell, G.; Mora, A.; Aresu, G.; Brittain, S.; Dent, W. R. F.; Pinte, C.; White, G. J.

Context. Observations of the atomic and molecular line emission associated with jets and outflows emitted by young stellar objects provide sensitive diagnostics of the excitation conditions, and can be used to trace the various evolutionary stages they pass through as they evolve to become main

Knotty protostellar jets as a signature of episodic protostellar accretion?

Science.gov (United States)

Vorobyov, Eduard I.; Elbakyan, Vardan G.; Plunkett, Adele L.; Dunham, Michael M.; Audard, Marc; Guedel, Manuel; Dionatos, Odysseas

2018-05-01

Aims: We aim to study the causal link between the knotty jet structure in CARMA 7, a young Class 0 protostar in the Serpens South cluster, and episodic accretion in young protostellar disks. Methods: We used numerical hydrodynamics simulations to derive the protostellar accretion history in gravitationally unstable disks around solar-mass protostars. We compared the time spacing between luminosity bursts Δτmod, caused by dense clumps spiralling on the protostar, with the differences of dynamical timescales between the knots Δτobs in CARMA 7. Results: We found that the time spacing between the bursts have a bi-modal distribution caused by isolated and clustered luminosity bursts. The former are characterized by long quiescent periods between the bursts with Δτmod = a few × (103-104) yr, whereas the latter occur in small groups with time spacing between the bursts Δτmod = a few × (10-102) yr. For the clustered bursts, the distribution of Δτmod in our models can be fit reasonably well to the distribution of Δτobs in the protostellar jet of CARMA 7, if a certain correction for the (yet unknown) inclination angle with respect to the line of sight is applied. The Kolmogorov-Smirnov test on the model and observational data sets suggests the best-fit values for the inclination angles of 55-80°, which become narrower (75-80°) if only strong luminosity bursts are considered. The dynamical timescales of the knots in the jet of CARMA 7 are too short for a meaningful comparison with the long time spacings between isolated bursts in our models. Moreover, the exact sequences of time spacings between the luminosity bursts in our models and knots in the jet of CARMA 7 were found difficult to match. Conclusions: Given the short time that has passed since the presumed luminosity bursts (tens to hundreds years), a possible overabundance of the gas-phase CO in the envelope of CARMA 7 compared to what could be expected from the current luminosity may be used to confirm

PACS industry in Korea

Science.gov (United States)

Kim, Hee-Joung

2002-05-01

PACS industry in Korea has been rapidly growing, since government had supported collaborative PACS project between industry and university hospital. In the beginning, PACS industry had focused on developing peripheral PACS solutions, while the Korea PACS society was being formed. A few companies had started developing and installing domestic large-scale full-PACS system for teaching hospitals. Several years later, many hospitals have installed full-PACS system with national policy of reimbursement for PACS exams in November 1999. Both experiences of full-PACS installation and national policy generated tremendous intellectual and technological expertise about PACS at all levels, clinical, hospital management, education, and industrial sectors. There are now more than 20 domestic PACS companies. They have enough experiences which are capable of installing a truly full-PACS system for large-scale teaching hospitals. As an example, a domestic company had installed more than 40 full-PACS systems within 2-3 years. Enough experiences of full-PACS installation in Korea lead PACS industry to start exporting their full-PACS solutions. However, further understanding and timely implementation of continuously evolving international standard and integrated healthcare enterprise concepts may be necessary for international leading of PACS technologies for the future.

The formation of molecules in protostellar winds

International Nuclear Information System (INIS)

Glassgold, A.E.; Mamon, G.A.; Huggins, P.J.

1991-01-01

The production and destruction processes for molecules in very fast protostellar winds are analyzed and modeled with a one-dimensional chemical kinetics code. Radial density and temperature distributions suggested by protostellar theory are explored as are a range of mass-loss rates. The efficiency of in situ formation of heavy molecules is found to be high if the wind temperature falls sufficiently rapidly, as indicated by theory. The degree of molecular conversion is a strong function of the mass-loss rate and of density gradients associated with the acceleration and collimation of the wind. Even in cases where essentially all of the heavy atoms are processed into molecules, a significant fraction of atomic hydrogen remains so that hghly molecular, protostellar winds are able to emit the 21-cm line. Although CO has a substantial abundance in most models relevant to very young protostars, high abundances of other molecules such as SiO and H2O signify more complete association characteristic of winds containing regions of very high density. Although the models apply only to regions close to the protostar, they are in qualitative accord with recent observations at much larger distances of both atomic and molecular emission from extremely high-velocity flow. 57 refs

A HERSCHEL AND APEX CENSUS OF THE REDDEST SOURCES IN ORION: SEARCHING FOR THE YOUNGEST PROTOSTARS

Energy Technology Data Exchange (ETDEWEB)

Stutz, Amelia M.; Robitaille, Thomas; Henning, Thomas; Krause, Oliver [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Tobin, John J. [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Stanke, Thomas [ESO, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei Muenchen (Germany); Megeath, S. Thomas; Fischer, William J. [Department of Physics and Astronomy, University of Toledo, 2801 W. Bancroft Street, Toledo, OH 43606 (United States); Ali, Babar; Furlan, Elise [NHSC/IPAC/Caltech, 770 S. Wilson Avenue, Pasadena, CA 91125 (United States); Di Francesco, James [National Research Council of Canada, Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Hartmann, Lee [Department of Astronomy, University of Michigan, 830 Dennison Building, 500 Church Street, Ann Arbor, MI 48109 (United States); Osorio, Mayra [Instituto de Astrofisica de Andalucia, CSIC, Camino Bajo de Huetor 50, E-18008 Granada (Spain); Wilson, Thomas L. [Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375 (United States); Allen, Lori [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Manoj, P., E-mail: stutz@mpia.de [Department of Physics and Astronomy, 500 Wilson Boulevard, University of Rochester, Rochester, NY 14627 (United States)

2013-04-10

We perform a census of the reddest, and potentially youngest, protostars in the Orion molecular clouds using data obtained with the PACS instrument on board the Herschel Space Observatory and the LABOCA and SABOCA instruments on APEX as part of the Herschel Orion Protostar Survey (HOPS). A total of 55 new protostar candidates are detected at 70 {mu}m and 160 {mu}m that are either too faint (m{sub 24} > 7 mag) to be reliably classified as protostars or undetected in the Spitzer/MIPS 24 {mu}m band. We find that the 11 reddest protostar candidates with log {lambda}F{sub {lambda}}70/{lambda}F{sub {lambda}}24 > 1.65 are free of contamination and can thus be reliably explained as protostars. The remaining 44 sources have less extreme 70/24 colors, fainter 70 {mu}m fluxes, and higher levels of contamination. Taking the previously known sample of Spitzer protostars and the new sample together, we find 18 sources that have log {lambda}F{sub {lambda}}70/{lambda}F{sub {lambda}}24 > 1.65; we name these sources 'PACS Bright Red sources', or PBRs. Our analysis reveals that the PBR sample is composed of Class 0 like sources characterized by very red spectral energy distributions (SEDs; T{sub bol} < 45 K) and large values of sub-millimeter fluxes (L{sub smm}/L{sub bol} > 0.6%). Modified blackbody fits to the SEDs provide lower limits to the envelope masses of 0.2-2 M{sub Sun} and luminosities of 0.7-10 L{sub Sun }. Based on these properties, and a comparison of the SEDs with radiative transfer models of protostars, we conclude that the PBRs are most likely extreme Class 0 objects distinguished by higher than typical envelope densities and hence, high mass infall rates.

Infall and outflow motions towards a sample of massive star-forming regions from the RMS survey

Science.gov (United States)

Cunningham, N.; Lumsden, S. L.; Moore, T. J. T.; Maud, L. T.; Mendigutía, I.

2018-06-01

We present the results of an outflow and infall survey towards a distance-limited sample of 31 massive star-forming regions drawn from the Red MSX source (RMS) survey. The presence of young, active outflows is identified from SiO (8-7) emission and the infall dynamics are explored using HCO+/H13CO+ (4-3) emission. We investigate if the infall and outflow parameters vary with source properties, exploring whether regions hosting potentially young active outflows show similarities or differences with regions harbouring more evolved, possibly momentum-driven, `fossil' outflows. SiO emission is detected towards approximately 46 per cent of the sources. When considering sources with and without an SiO detection (i.e. potentially active and fossil outflows, respectively), only the 12CO outflow velocity shows a significant difference between samples, indicating SiO is more prevalent towards sources with higher outflow velocities. Furthermore, we find the SiO luminosity increases as a function of the Herschel 70 μm to WISE 22 μm flux ratio, suggesting the production of SiO is prevalent in younger, more embedded regions. Similarly, we find tentative evidence that sources with an SiO detection have a smaller bolometric luminosity-to-mass ratio, indicating SiO (8-7) emission is associated with potentially younger regions. We do not find a prevalence towards sources displaying signatures of infall in our sample. However, the higher energy HCO+ transitions may not be the best suited tracer of infall at this spatial resolution in these regions.

Towards a theory of PACS deployment: an integrative PACS maturity framework.

Science.gov (United States)

van de Wetering, Rogier; Batenburg, Ronald

2014-06-01

Owing to large financial investments that go along with the picture archiving and communication system (PACS) deployments and inconsistent PACS performance evaluations, there is a pressing need for a better understanding of the implications of PACS deployment in hospitals. We claim that there is a gap in the research field, both theoretically and empirically, to explain the success of the PACS deployment and maturity in hospitals. Theoretical principles are relevant to the PACS performance; maturity and alignment are reviewed from a system and complexity perspective. A conceptual model to explain the PACS performance and a set of testable hypotheses are then developed. Then, structural equation modeling (SEM), i.e. causal modeling, is applied to validate the model and hypotheses based on a research sample of 64 hospitals that use PACS, i.e. 70 % of all hospitals in the Netherlands. Outcomes of the SEM analyses substantiate that the measurements of all constructs are reliable and valid. The PACS alignment-modeled as a higher-order construct of five complementary organizational dimensions and maturity levels-has a significant positive impact on the PACS performance. This result is robust and stable for various sub-samples and segments. This paper presents a conceptual model that explains how alignment in deploying PACS in hospitals is positively related to the perceived performance of PACS. The conceptual model is extended with tools as checklists to systematically identify the improvement areas for hospitals in the PACS domain. The holistic approach towards PACS alignment and maturity provides a framework for clinical practice.

Overview of PACS

Science.gov (United States)

Vanden Brink, John A.

1995-08-01

Development of the DICOM standard and incremental developments in workstation, network, compression, archiving, and digital x-ray technology have produced cost effective image communication possibilities for selected medical applications. The emerging markets include modality PACS, mini PACS, and teleradiology. Military and VA programs lead the way in the move to adopt PACS technology. Commercial markets for PACS components and PAC systems are at LR400 million growing to LR500 million in 1996.

PACS in nuclear medicine

International Nuclear Information System (INIS)

Kang, Keon Wook

2000-01-01

PACS (Picture Archiving and Communication System) is being rapidly spread and installed in many hospitals, but most of the system do not include nuclear medicine field. Although additional costs of hardware for nuclear medicine PACS is low, the complexity in developing viewing software and little market have made the nuclear medicine PACS not popular. Most PACS utilize DICOM 3.0 as standard format, but standard format in nuclear medicine has been Interfile. Interfile should be converted into DICOM format if nuclear images are to be stored and visualized in most PACS. Nowadays, many vendors supply the DICOM option in gamma camera and PET. Several hospitals in Korea have already installed nucler PACS with DICOM, but only the screen captured images are supplied. Software for visualizing pseudo-color with color lookup tables and expressing with volume view should be developed to fulfill the demand of referring physicians and nuclear medicine physicians. PACS is going to integrate not only radiologic images but also endoscopic and pathologic images. Web and PC based PACS is now a trend and is much compatible with nuclear medicine PACS. Most important barrier for nuclear medicine PACS that we encounter is not a technical problem, but indifference of investor such as administrator of hospital or PACS. Now it is time to support and invest for the development of nuclear medicine PACS

Data processing pipeline for Herschel HIFI

NARCIS (Netherlands)

Shipman, R. F.; Beaulieu, S. F.; Teyssier, D.; Morris, P.; Rengel, M.; McCoey, C.; Edwards, K.; Kester, D.; Lorenzani, A.; Coeur-Joly, O.; Melchior, M.; Xie, J.; Sanchez, E.; Zaal, P.; Avruch, I.; Borys, C.; Braine, J.; Comito, C.; Delforge, B.; Herpin, F.; Hoac, A.; Kwon, W.; Lord, S. D.; Marston, A.; Mueller, M.; Olberg, M.; Ossenkopf, V.; Puga, E.; Akyilmaz-Yabaci, M.

2017-01-01

Context. The HIFI instrument on the Herschel Space Observatory performed over 9100 astronomical observations, almost 900 of which were calibration observations in the course of the nearly four-year Herschel mission. The data from each observation had to be converted from raw telemetry into

The near-infrared outflow and cavity of the proto-brown dwarf candidate ISO-Oph 200

Science.gov (United States)

Whelan, E. T.; Riaz, B.; Rouzé, B.

2018-03-01

In this Letter a near-infrared integral field study of a proto-brown dwarf candidate is presented. A 0.''5 blue-shifted outflow is detected in both H2 and [Fe II] lines at Vsys = (–35 ± 2) km s-1 and Vsys = (–51 ± 5) km s-1 respectively. In addition, slower ( ±10 km s-1) H2 emission is detected out to <5.''4, in the direction of both the blue and red-shifted outflow lobes but along a different position angle to the more compact faster emission. It is argued that the more compact emission is a jet and the extended H2 emission is tracing a cavity. The source extinction is estimated at Av = 18 ± 1 mag and the outflow extinction at Av = 9 ± 0.4 mag. The H2 outflow temperature is calculated to be 1422 ± 255 K and the electron density of the [Fe II] outflow is measured at 10 000 cm-3. Furthermore, the mass outflow rate is estimated at Ṁout [H2] = 3.8 × 10-10 M⊙ yr-1 and Ṁout[Fe II] = 1 × 10-8 M⊙ yr-1. Ṁout[Fe II] takes a Fe depletion of 88% into account. The depletion is investigated using the ratio of the [Fe II] 1.257 μm and [P II] 1.188 μm lines. Using the Paβ and Brγ lines and a range in stellar mass and radius Ṁacc is calculated to be (3–10) × 10-8 M⊙ yr-/1. Comparing these rates puts the jet efficiency in line with predictions of magneto-centrifugal models of jet launching in low mass protostars. This is a further case of a brown dwarf outflow exhibiting analogous properties to protostellar jets. Based on Observations collected with SINFONI at the Very Large Telescope on Cerro Paranal (Chile), operated by the European Southern Observatory (ESO). Program ID: 097.C-0732(A).

Charles Darwin and John Herschel

Science.gov (United States)

Warner, B.

2009-11-01

The influence of John Herschel on the philosophical thoughts of Charles Darwin, both through the former's book, Natural Philosophy, and through their meeting in 1836 at the Cape of Good Hope, is discussed. With Herschel having himself speculated on evolution just a few months before he met Darwin, it is probable that he stimulated at least the beginnings of the latter's lifelong work on the subject.

dicomPACS: PACS Leader in Germany - Kodak Partner

OpenAIRE

Maziyar Shakeri

2007-01-01

History of Distributor: We are PDP Co. (Pardazesh Danesh Pezeshki) founded in 1998 with more than 8 years Experiments in Diagnostic Medical Imaging Market .we launched our New Division in 2002 for Digital Imaging and Softcopy under name of PDP View . We studied our market demands and PACS Provider Companies for 2 years and finally we signed the Contract with the first leader German PACS Provider named dicomPACS ® ."nWe are the only company who their 3 engineers well trained in th...

The Herschel/HIFI spectral survey of OMC-2 FIR 4 (CHESS). An overview of the 480 to 1902 GHz range

Science.gov (United States)

Kama, M.; López-Sepulcre, A.; Dominik, C.; Ceccarelli, C.; Fuente, A.; Caux, E.; Higgins, R.; Tielens, A. G. G. M.; Alonso-Albi, T.

2013-08-01

Context. Broadband spectral surveys of protostars offer a rich view of the physical, chemical and dynamical structure and evolution of star-forming regions. The Herschel Space Observatory opened up the terahertz regime to such surveys, giving access to the fundamental transitions of many hydrides and to the high-energy transitions of many other species. Aims: A comparative analysis of the chemical inventories and physical processes and properties of protostars of various masses and evolutionary states is the goal of the Herschel CHEmical Surveys of Star forming regions (CHESS) key program. This paper focusses on the intermediate-mass protostar, OMC-2 FIR 4. Methods: We obtained a spectrum of OMC-2 FIR 4 in the 480 to 1902 GHz range with the HIFI spectrometer onboard Herschel and carried out the reduction, line identification, and a broad analysis of the line profile components, excitation, and cooling. Results: We detect 719 spectral lines from 40 species and isotopologs. The line flux is dominated by CO, H2O, and CH3OH. The line profiles are complex and vary with species and upper level energy, but clearly contain signatures from quiescent gas, a broad component likely due to an outflow, and a foreground cloud. Conclusions: We find abundant evidence for warm, dense gas, as well as for an outflow in the field of view. Line flux represents 2% of the 7 L⊙ luminosity detected with HIFI in the 480 to 1250 GHz range. Of the total line flux, 60% is from CO, 13% from H2O and 9% from CH3OH. A comparison with similar HIFI spectra of other sources is set to provide much new insight into star formation regions, a case in point being a difference of two orders of magnitude in the relative contribution of sulphur oxides to the line cooling of Orion KL and OMC-2 FIR 4. Appendix A is available in electronic form at http://www.aanda.org

Measures of star formation rates from infrared (Herschel) and UV (GALEX) emissions of galaxies in the HerMES fields

Science.gov (United States)

Buat, V.; Giovannoli, E.; Burgarella, D.; Altieri, B.; Amblard, A.; Arumugam, V.; Aussel, H.; Babbedge, T.; Blain, A.; Bock, J.; Boselli, A.; Castro-Rodríguez, N.; Cava, A.; Chanial, P.; Clements, D. L.; Conley, A.; Conversi, L.; Cooray, A.; Dowell, C. D.; Dwek, E.; Eales, S.; Elbaz, D.; Fox, M.; Franceschini, A.; Gear, W.; Glenn, J.; Griffin, M.; Halpern, M.; Hatziminaoglou, E.; Heinis, S.; Ibar, E.; Isaak, K.; Ivison, R. J.; Lagache, G.; Levenson, L.; Lonsdale, C. J.; Lu, N.; Madden, S.; Maffei, B.; Magdis, G.; Mainetti, G.; Marchetti, L.; Morrison, G. E.; Nguyen, H. T.; O'Halloran, B.; Oliver, S. J.; Omont, A.; Owen, F. N.; Page, M. J.; Pannella, M.; Panuzzo, P.; Papageorgiou, A.; Pearson, C. P.; Pérez-Fournon, I.; Pohlen, M.; Rigopoulou, D.; Rizzo, D.; Roseboom, I. G.; Rowan-Robinson, M.; Sánchez Portal, M.; Schulz, B.; Seymour, N.; Shupe, D. L.; Smith, A. J.; Stevens, J. A.; Strazzullo, V.; Symeonidis, M.; Trichas, M.; Tugwell, K. E.; Vaccari, M.; Valiante, E.; Valtchanov, I.; Vigroux, L.; Wang, L.; Ward, R.; Wright, G.; Xu, C. K.; Zemcov, M.

2010-11-01

The reliability of infrared (IR) and ultraviolet (UV) emissions to measure star formation rates (SFRs) in galaxies is investigated for a large sample of galaxies observed with the Spectral and Photometric Imaging Receiver (SPIRE) and the Photodetector Array Camera and Spectrometer (PACS) instruments on Herschel as part of the Herschel Multi-Tiered Extragalactic Survey (HerMES) project. We build flux-limited 250-μm samples of sources at redshift z 500 μm. Dust attenuation is discussed on the basis of commonly used diagnostics: the LIR/LUV ratio and the slope, β, of the UV continuum. A mean dust attenuation AUV of mag is measured in the samples. LIR/LUV is found to correlate with LIR. Galaxies with and 0.5 recipe commonly applied to local starbursts is found to overestimate the dust attenuation correction in our galaxy sample by a factor of ~2-3. The SFRs deduced from LIR are found to account for about 90 per cent of the total SFR; this percentage drops to 71 per cent for galaxies with (or ). For these faint objects, one needs to combine UV and IR emissions to obtain an accurate measure of the SFR.

A STUDY OF RADIO POLARIZATION IN PROTOSTELLAR JETS

Energy Technology Data Exchange (ETDEWEB)

Cécere, Mariana [Instituto de Astronomía Teórica y Experimental, Universidad Nacional de Córdoba, X5000BGR, Córdoba (Argentina); Velázquez, Pablo F.; De Colle, Fabio; Esquivel, Alejandro [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Apdo. Postal 70-543, CP: 04510, D.F., México (Mexico); Araudo, Anabella T. [University of Oxford, Astrophysics, Keble Road, Oxford OX1 3RH (United Kingdom); Carrasco-González, Carlos; Rodríguez, Luis F. [Instituto de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, Apdo. Postal 3-72, 58090, Morelia, Michoacán, México (Mexico)

2016-01-10

Synchrotron radiation is commonly observed in connection with shocks of different velocities, ranging from relativistic shocks associated with active galactic nuclei, gamma-ray bursts, or microquasars, to weakly or non-relativistic flows such as those observed in supernova remnants. Recent observations of synchrotron emission in protostellar jets are important not only because they extend the range over which the acceleration process works, but also because they allow us to determine the jet and/or interstellar magnetic field structure, thus giving insights into the jet ejection and collimation mechanisms. In this paper, we compute for the first time polarized (synchrotron) and non-polarized (thermal X-ray) synthetic emission maps from axisymmetrical simulations of magnetized protostellar jets. We consider models with different jet velocities and variability, as well as a toroidal or helical magnetic field. Our simulations show that variable, low-density jets with velocities of ∼1000 km s{sup −1} and ∼10 times lighter than the environment can produce internal knots with significant synchrotron emission and thermal X-rays in the shocked region of the leading bow shock moving in a dense medium. While models with a purely toroidal magnetic field show a very large degree of polarization, models with a helical magnetic field show lower values and a decrease of the degree of polarization, in agreement with observations of protostellar jets.

Factors causing PAC cake fouling in PAC-MF (powdered activated carbon-microfiltration) water treatment systems.

Science.gov (United States)

Zhao, P; Takizawa, S; Katayama, H; Ohgaki, S

2005-01-01

Two pilot-scale powdered activated carbon-microfiltration (PAC-MF) reactors were operated using river water pretreated by a biofilter. A high permeate flux (4 m/d) was maintained in two reactors with different particle sizes of PAC. High concentration (20 g/L) in the PAC adsorption zone demonstrated 60-80% of organic removal rates. Analysis on the PAC cake fouling demonstrated that attached metal ions play more important role than organic matter attached on PAC to the increase of PAC cake resistance. Effects of factors which may cause PAC cake fouling in PAC-MF process were investigated and evaluated by batch experiments, further revealing that small particulates and metal ions in raw water impose prominent influence on the PAC cake layer formation. Fe (II) precipitates after being oxidized to Fe (III) during PAC adsorption and thus Fe(ll) colloids display more significant effect than other metal ions. At a high flux, PAC cake layer demonstrated a higher resistance with larger PAC due to association among colloids, metals and PAC particles, and easy migration of small particles in raw water into the void space in the PAC cake layer. Larger PAC possesses much more non-uniform particle size distribution and larger void space, making it easier for small colloids to migrate into the voids and for metal ions to associate with PAC particles by bridge effect, hence speeding up and intensifying the of PAC cake fouling on membrane surface.

HERschel key program heritage: A far-infrared source catalog for the Magellanic Clouds

International Nuclear Information System (INIS)

Seale, Jonathan P.; Meixner, Margaret; Sewiło, Marta; Babler, Brian; Engelbracht, Charles W.; Misselt, Karl; Montiel, Edward; Gordon, Karl; Roman-Duval, Julia; Hony, Sacha; Okumura, Koryo; Panuzzo, Pasquale; Sauvage, Marc; Boyer, Martha L.; Chen, C.-H. Rosie; Indebetouw, Remy; Matsuura, Mikako; Oliveira, Joana M.; Loon, Jacco Th. van; Srinivasan, Sundar

2014-01-01

Observations from the HERschel Inventory of the Agents of Galaxy Evolution (HERITAGE) have been used to identify dusty populations of sources in the Large and Small Magellanic Clouds (LMC and SMC). We conducted the study using the HERITAGE catalogs of point sources available from the Herschel Science Center from both the Photodetector Array Camera and Spectrometer (PACS; 100 and 160 μm) and Spectral and Photometric Imaging Receiver (SPIRE; 250, 350, and 500 μm) cameras. These catalogs are matched to each other to create a Herschel band-merged catalog and then further matched to archival Spitzer IRAC and MIPS catalogs from the Spitzer Surveying the Agents of Galaxy Evolution (SAGE) and SAGE-SMC surveys to create single mid- to far-infrared (far-IR) point source catalogs that span the wavelength range from 3.6 to 500 μm. There are 35,322 unique sources in the LMC and 7503 in the SMC. To be bright in the FIR, a source must be very dusty, and so the sources in the HERITAGE catalogs represent the dustiest populations of sources. The brightest HERITAGE sources are dominated by young stellar objects (YSOs), and the dimmest by background galaxies. We identify the sources most likely to be background galaxies by first considering their morphology (distant galaxies are point-like at the resolution of Herschel) and then comparing the flux distribution to that of the Herschel Astrophysical Terahertz Large Area Survey (ATLAS) survey of galaxies. We find a total of 9745 background galaxy candidates in the LMC HERITAGE images and 5111 in the SMC images, in agreement with the number predicted by extrapolating from the ATLAS flux distribution. The majority of the Magellanic Cloud-residing sources are either very young, embedded forming stars or dusty clumps of the interstellar medium. Using the presence of 24 μm emission as a tracer of star formation, we identify 3518 YSO candidates in the LMC and 663 in the SMC. There are far fewer far-IR bright YSOs in the SMC than the LMC

HERschel key program heritage: A far-infrared source catalog for the Magellanic Clouds

Energy Technology Data Exchange (ETDEWEB)

Seale, Jonathan P.; Meixner, Margaret; Sewiło, Marta [The Johns Hopkins University, Department of Physics and Astronomy, 366 Bloomberg Center, 3400 N. Charles Street, Baltimore, MD 21218 (United States); Babler, Brian [Department of Astronomy, 475 North Charter St., University of Wisconsin, Madison, WI 53706 (United States); Engelbracht, Charles W.; Misselt, Karl; Montiel, Edward [Steward Observatory, University of Arizona, 933 North Cherry Ave., Tucson, AZ 85721 (United States); Gordon, Karl; Roman-Duval, Julia [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Hony, Sacha; Okumura, Koryo; Panuzzo, Pasquale; Sauvage, Marc [CEA, Laboratoire AIM, Irfu/SAp, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Boyer, Martha L. [Observational Cosmology Laboratory, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Chen, C.-H. Rosie [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Indebetouw, Remy [National Radio Astronomy Observatory, 520 Edgemont Road Charlottesville, VA 22903 (United States); Matsuura, Mikako [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Oliveira, Joana M.; Loon, Jacco Th. van [School of Physical and Geographical Sciences, Lennard-Jones Laboratories, Keele University, Staffordshire ST5 5BG (United Kingdom); Srinivasan, Sundar [UPMC-CNRS UMR7095, Institute d' Astrophysique de Paris, F-75014 Paris (France); and others

2014-12-01

Observations from the HERschel Inventory of the Agents of Galaxy Evolution (HERITAGE) have been used to identify dusty populations of sources in the Large and Small Magellanic Clouds (LMC and SMC). We conducted the study using the HERITAGE catalogs of point sources available from the Herschel Science Center from both the Photodetector Array Camera and Spectrometer (PACS; 100 and 160 μm) and Spectral and Photometric Imaging Receiver (SPIRE; 250, 350, and 500 μm) cameras. These catalogs are matched to each other to create a Herschel band-merged catalog and then further matched to archival Spitzer IRAC and MIPS catalogs from the Spitzer Surveying the Agents of Galaxy Evolution (SAGE) and SAGE-SMC surveys to create single mid- to far-infrared (far-IR) point source catalogs that span the wavelength range from 3.6 to 500 μm. There are 35,322 unique sources in the LMC and 7503 in the SMC. To be bright in the FIR, a source must be very dusty, and so the sources in the HERITAGE catalogs represent the dustiest populations of sources. The brightest HERITAGE sources are dominated by young stellar objects (YSOs), and the dimmest by background galaxies. We identify the sources most likely to be background galaxies by first considering their morphology (distant galaxies are point-like at the resolution of Herschel) and then comparing the flux distribution to that of the Herschel Astrophysical Terahertz Large Area Survey (ATLAS) survey of galaxies. We find a total of 9745 background galaxy candidates in the LMC HERITAGE images and 5111 in the SMC images, in agreement with the number predicted by extrapolating from the ATLAS flux distribution. The majority of the Magellanic Cloud-residing sources are either very young, embedded forming stars or dusty clumps of the interstellar medium. Using the presence of 24 μm emission as a tracer of star formation, we identify 3518 YSO candidates in the LMC and 663 in the SMC. There are far fewer far-IR bright YSOs in the SMC than the LMC

Towards a theory of PACS deployment: an integrative PACS maturity framework.

NARCIS (Netherlands)

Wetering, R. van de; Batenburg, R.

2014-01-01

Owing to large financial investments that go along with the picture archiving and communication system (PACS) deployments and inconsistent PACS performance evaluations, there is a pressing need for a better understanding of the implications of PACS deployment in hospitals. We claim that there is a

The scientific legacy of William Herschel

CERN Document Server

2018-01-01

This book presents a modern scholarly analysis of issues associated with England’s most famous astronomer, William Herschel. The world’s leading experts on Herschel, discoverer of the planet Uranus, here offer their combined wisdom on many aspects of his life and astronomical research. Solar system topics include comets, Earth’s Moon, and the spurious moons of Uranus, all objects whose observation was pioneered by Herschel.  The contributors examine his study of the structure of the Milky Way and an in-depth look at the development of the front view telescopes he built. The popular subject of extraterrestrial life is looked at from the point of view of both William Herschel and his son John, both of whom had an interest in the topic. William’s personal development through the educational system of the late eighteenth-century is also explored, and the wide range of verse and satire in various languages associated with his discoveries is collected here for the first time. Hershel worked at a time of i...

Protostellar formation in rotation interstellar clouds. III. Nonaxisymmetric collapse

International Nuclear Information System (INIS)

Boss, A.P.

1980-01-01

A full three spatial-dimension gravitational hydrodynamics code has been used to follow the collapse of isothermal rotating clouds subjected to various nonaxialy symmetric perturbations (NAP). An initially axially symmetric cloud collapsed to form a ring which then fragmented into a binary protostellar system. A low thermal energy cloud with a large bar-shaped NAP collapsed and fragmented directly into a binary; higher thermal energy clouds damp out such NAPs while higher rotational rotational energy clouds produce binaries with wider separations. Fragmentation into single and binary systems has been seen. The tidal effects of other nearby protostellar clouds are shown to have an important effect upon the collapse and should not be neglected. The three-dimensional calculations indicate that isothermal interstellar clouds may fragment (with or without passing through a transitory ring phase) into protostellar objects while still in the isothermal regime. The fragments obtained have masses and specific spin angular momenta roughly a 10th that of the original cloud. Interstellar clouds and their fragments may pass through successive collapse phases with fragmentation and reduction of spin angular momentum (by conversion to orbital angular momentum and preferential accretion of low angular momentum matter) terminating in the formation of pre--main-sequence stars with the observed pre--main-sequence rotation rates

High-J CO survey of low-mass protostars observed with Herschel-HIFI

DEFF Research Database (Denmark)

Yıldız, U. A.; Kristensen, L. E.; van Dishoeck, E. F.

2013-01-01

with Herschel (WISH) key program. This is the first large spectrally resolved high-J CO survey conducted for these types of sources. Complementary lower J CO maps were observed using ground-based telescopes, such as the JCMT and APEX and convolved to matching beam sizes. Results: The 12CO 10-9 line is detected...... the 13CO and 12CO excitation temperatures, due to lack of UV heating and outflow components in those models. The H2O 110 - 101/CO 10-9 intensity ratio does not change significantly with velocity, in contrast to the H2O/CO 3-2 ratio, indicating that CO 10-9 is the lowest transition for which the line...

EXTREME CONDITIONS IN A CLOSE ANALOG TO THE YOUNG SOLAR SYSTEM: HERSCHEL OBSERVATIONS OF ε ERIDANI

Energy Technology Data Exchange (ETDEWEB)

Greaves, J. S. [SUPA, Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS (United Kingdom); Sibthorpe, B.; Holland, W. S. [UK Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Acke, B.; Vandenbussche, B.; Blommaert, J. A. D. L. [Instituut voor Sterrenkunde, K. U. Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Pantin, E. E. [Laboratoire AIM, CEA/DSM-CNRS-Universit Paris Diderot, IRFU/Service dAstrophysique, Bat.709, CEA-Saclay, F-91191 Gif- sur-Yvette Cedex (France); Olofsson, G.; Brandeker, A.; De Vries, B. L. [Stockholm University Astrobiology Centre, SE-106 91 Stockholm (Sweden); Dominik, C. [Astronomical Institute Anton Pannekoek, University of Amsterdam, P.O. Box 94249, 1090-GE Amsterdam (Netherlands); Barlow, M. J. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Bendo, G. J. [Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Dent, W. R. F. [ALMA SCO, Alonso de Cordova 3107, Vitacura, Casilla 763 0355, Santiago (Chile); Di Francesco, J. [Herzberg Astronomy and Astrophysics Programs, National Research Council of Canada, 5071 West Saanich Road, Victoria, BC, V9E 2E7 (Canada); Fridlund, M. [ESA, SRE-SA, Keplerlaan 1, NL-2201 AZ Noordwijk (Netherlands); Gear, W. K. [School of Physics and Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff CF24 3AA (United Kingdom); Harvey, P. M. [Astronomy Department, University of Texas, Austin, TX 78712 (United States); Hogerheijde, M. R. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300-RA Leiden (Netherlands); Ivison, R. J., E-mail: jsg5@st-andrews.ac.uk [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); and others

2014-08-10

Far-infrared Herschel images of the ε Eridani system, seen at a fifth of the Sun's present age, resolve two belts of debris emission. Fits to the 160 μm PACS image yield radial spans for these belts of 12-16 and 54-68 AU. The south end of the outer belt is ≈10% brighter than the north end in the PACS+SPIRE images at 160, 250, and 350 μm, indicating a pericenter glow attributable to a planet ''c''. From this asymmetry and an upper bound on the offset of the belt center, this second planet should be mildly eccentric (e{sub c} ≈ 0.03-0.3). Compared to the asteroid and Kuiper Belts of the young Sun, the ε Eri belts are intermediate in brightness and more similar to each other, with up to 20 km sized collisional fragments in the inner belt totaling ≈5% of an Earth mass. This reservoir may feed the hot dust close to the star and could send many impactors through the Habitable Zone, especially if it is being perturbed by the suspected planet ε Eri b, at semi-major axis ≈3 AU.

Dental PACS development in Korea

International Nuclear Information System (INIS)

Kim, Eun Kyung

2008-01-01

Picture archiving and communication system (PACS) is an image information technology system for the transmission and storage of medical images. In Korea the first full PACS was installed at Samsung Medical Center in 1994, but, the rate of distribution was very slow. The government's approval for the medical insurance reimbursement for full PACS examinations in November 1999 became the turning point. Thereafter the number of hospitals with full PACS has steeply increased. In September of this year, PACS was installed at 906 medical institutes, including most of university hospitals and general hospitals. The first full dental PACS was installed at Wonkwang University Dental Hospital in 2002. Now ten out of eleven university dental hospitals implemented full dental PACS. The current status and technological factors of dental PACS in Korean university dental hospitals and the future perspectives of dental PACS are described.

Three-dimensional dynamics of protostellar evolution

International Nuclear Information System (INIS)

Cook, T.L.; Harlow, F.H.

1978-01-01

A three-dimensional finite difference numerical methodology has been developed for self-gravitating, rotating gaseous systems. The fully nonlinear equations for time-varying fluid dynamics are solved by high-speed computer in a cylindrical coordinate system rotating with an instantaneous angular velocity. The time-dependent adiabatic collapse of gravitationally bound, rotating, protostellar clouds is studied for specified uniform and nonuniform initial conditions. Uniform clouds can form axisymmetric, rotating toroidal configurations. If the thermal pressure is high, nonuniform clouds can also collapse to axisymmetric ellipsoids. For low thermal pressures, however, the collapsing cloud is unstable to perturbations. The resulting fragmentation of unstable protostellar clouds is investigated by studying the response of rotating, self-gravitating, equilibrium toroids to nonaxisymmetric perturbations. The detailed evolution of the fragmentation toroid depends upon a nondimensional function of the initial entropy, the total mass in the toroid, the angular velocity of rotation, and the number of perturbation wave-lengths around the circumference of the toroid. For low and intermediate entropies, the configuration develops into corotating components with spiral streamers. In the spiral regions retrograde vortices are observed in some examples. For high levels of entropy, barred spirals can exist as intermediate states of the fragmentation

A Comprehensive Study of the Cold Dust and Gas in Galactic Winds

Science.gov (United States)

Veilleux, Sylvain

determine whether the circumgalactic dust properties (e.g., scale height, temperature, mass fraction relative to total) vary with host properties (e.g., SFRs, SFR surface densities, stellar masses, galaxy types). In addition, we will carry out a systematic analysis of the Herschel-PACS two dimensional spectroscopic data on a select group of the nearest and best known starburst and AGN-driven GWs to provide further insight into the physical entrainment and mass-loading mechanisms of these outflows. The entire Herschel-PACS spectroscopic data archive will also be searched for more distant GWs, using the P-Cygni profiles or blueshifted absorption wings of OH 79 and/or 119 um as unambiguous signatures of outflows, albeit spatially unresolved. High-quality spectra of these features exist for more than 300 galaxies, spanning three orders of magnitude in SFR and stellar masses, ideally suited to provide an unprecedented census of the basic properties of molecular outflows (e.g., frequency of occurrence, kinematics). We expect that a subset of ~80 objects will also present Spitzer-IRS OH 35 um, which will be combined with OH 79 and/or 119 um to constrain the energetics (mass outflow rate, momentum flux, kinetic power) of these outflows. This represents an order-of magnitude increase in sample size over the current sample of molecular outflows with known energetics. This unique data set will allow us to make statistical statements about the origin (starburst vs AGN) and acceleration mechanism(s) (momentum- vs energydriven) of molecular outflows, and thus the impact they may have on their galaxy hosts and circumgalactic environments. These results will also be extremely useful for the interpretation of ALMA OH observations in the distant universe, where negative feedback from winds is expected to be even more important.

The protostar OMC-2 FIR 4: Results from the CHESS Herschel/HIFI spectral survey

Science.gov (United States)

Kama, Mihkel; Lopez-Sepulcre, Ana; Ceccarelli, Cecilia; Dominik, Carsten; Caux, Emmanuel; Fuente, Asuncion

2013-07-01

The intermediate-mass protostar OMC-2 FIR 4 in Orion is the focus of several ongoing studies, including a CHESS key programme Herschel/HIFI spectral survey. In this poster, we review recent CHESS results on this source, including the properties of the central hot core, the presence of a compact outflow, the spatial variation of the chemical composition, and the discovery of a tenuous foreground cloud. The HIFI spectrum of FIR 4 contains 719 lines from 40 species and isotopologs. Cooling by lines detectable with our sensitivity contributes 2% of the total in the 480 to 1900 GHz range. The total line flux is dominated by CO, followed by H2O and CH3OH. Initial comparisons with spectral surveys of other sources will also be presented.

Shimadzu AI-PACS 'SAIPACS'

International Nuclear Information System (INIS)

Andoh, Minoru; Asai, Shigeya; Matsui, Norihisa; Nishida, Shinichiro; Horino, Masato

1990-01-01

The PACS-WS named SAIPACS-WS(workstation) has been developed as the first step of complete PACS. This SAIPACS-WS is different from other PACS-WS's, because this is including computer aided diagnostic reporting and computer aided diagnosis by using artificial intelligence technique. In this paper we will report detail of the SAIPACS-WS and discuss the future development of the total PACS setting the SAIPACS-WS in its center. (author)

Data processing pipeline for Herschel HIFI

Science.gov (United States)

Shipman, R. F.; Beaulieu, S. F.; Teyssier, D.; Morris, P.; Rengel, M.; McCoey, C.; Edwards, K.; Kester, D.; Lorenzani, A.; Coeur-Joly, O.; Melchior, M.; Xie, J.; Sanchez, E.; Zaal, P.; Avruch, I.; Borys, C.; Braine, J.; Comito, C.; Delforge, B.; Herpin, F.; Hoac, A.; Kwon, W.; Lord, S. D.; Marston, A.; Mueller, M.; Olberg, M.; Ossenkopf, V.; Puga, E.; Akyilmaz-Yabaci, M.

2017-12-01

Context. The HIFI instrument on the Herschel Space Observatory performed over 9100 astronomical observations, almost 900 of which were calibration observations in the course of the nearly four-year Herschel mission. The data from each observation had to be converted from raw telemetry into calibrated products and were included in the Herschel Science Archive. Aims: The HIFI pipeline was designed to provide robust conversion from raw telemetry into calibrated data throughout all phases of the HIFI missions. Pre-launch laboratory testing was supported as were routine mission operations. Methods: A modular software design allowed components to be easily added, removed, amended and/or extended as the understanding of the HIFI data developed during and after mission operations. Results: The HIFI pipeline processed data from all HIFI observing modes within the Herschel automated processing environment as well as within an interactive environment. The same software can be used by the general astronomical community to reprocess any standard HIFI observation. The pipeline also recorded the consistency of processing results and provided automated quality reports. Many pipeline modules were in use since the HIFI pre-launch instrument level testing. Conclusions: Processing in steps facilitated data analysis to discover and address instrument artefacts and uncertainties. The availability of the same pipeline components from pre-launch throughout the mission made for well-understood, tested, and stable processing. A smooth transition from one phase to the next significantly enhanced processing reliability and robustness. Herschel was an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

DIRECT IMAGING OF A COMPACT MOLECULAR OUTFLOW FROM A VERY LOW LUMINOSITY OBJECT: L1521F-IRS

Energy Technology Data Exchange (ETDEWEB)

Takahashi, Satoko [Joint ALMA Observatory, Alonso de Cordova 3107, Vitacura, Santiago (Chile); Ohashi, Nagayoshi [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China); Bourke, Tyler L., E-mail: satoko.takahashi@nao.ac.jp [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2013-09-01

Studying the physical conditions of very low luminosity objects (VeLLOs; L{sub bol} < 0.1 L{sub Sun }) is important for understanding the earliest evolutionary stage of protostars and brown dwarfs. We report interferometric observations of the VeLLO L1521F-IRS, in {sup 12}CO (2-1) line emission and the 1.3 mm continuum emission, using the Submillimeter Array. With the {sup 12}CO (2-1) high-resolution observations, we have spatially resolved a compact but poorly collimated molecular outflow associated with L1521F-IRS for the first time. The blueshifted and redshifted lobes are aligned along the east and west side of L1521F-IRS with a lobe size of Almost-Equal-To 1000 AU. The estimated outflow mass, maximum outflow velocity, and outflow force are (9.0-80) Multiplication-Sign 10{sup -4} M{sub Sun }, 7.2 km s{sup -1}, and (7.4-66) Multiplication-Sign 10{sup -7} M{sub Sun} km s{sup -1} yr{sup -1}, respectively. The estimated outflow parameters such as size, mass, and momentum rate are similar to values derived for other VeLLOs, and are located at the lower end of values compared to previously studied outflows associated with low- to high-mass star-forming regions. Low-velocity less collimated (1.5 km s{sup -1}/1200 AU) and higher-velocity compact (4.0 km s{sup -1}/920 AU) outflow components are suggested by the data. These velocity structures are not consistent with those expected in the jet-driven or wind-driven outflow models, perhaps suggesting a remnant outflow from the first hydrostatic core as well as an undeveloped outflow from the protostar. Detection of an infrared source and compact millimeter continuum emission suggests the presence of the protostar, while its low bolometric luminosity (0.034-0.07 L{sub Sun }) and small outflow suggests that L1521F is in the earliest protostellar stage (<10{sup 4} yr) and contains a substellar mass object. The bolometric (or internal) luminosity of L1521F-IRS suggests that the current mass accretion rate is an order of

SCUBA and HIRES Results for Protostellar Cores in the MON OB1 Dark Cloud

Science.gov (United States)

Wolf-Chase, G.; Moriarty-Schieven, G.; Fich, M.; Barsony, M.

1999-05-01

We have used HIRES-processing of IRAS data and point-source modelling techniques (Hurt & Barsony 1996; O'Linger 1997; Barsony et al. 1998), together with submillimeter continuum imaging using the Submillimeter Common-User Bolometer Array (SCUBA) on the 15-meter James Clerk Maxwell Telescope (JCMT), to search CS cores in the Mon OB1 dark cloud (Wolf-Chase, Walker, & Lada 1995; Wolf-Chase & Walker 1995) for deeply embedded sources. These observations, as well as follow-up millimeter photometry at the National Radio Astronomy Observatory (NRAO) 12-meter telescope on Kitt Peak, have lead to the identification of two Class 0 protostellar candidates, which were previously unresolved from two brighter IRAS point sources (IRAS 06382+0939 & IRAS 06381+1039) in this cloud. Until now, only one Class 0 object had been confirmed in Mon OB1; the driving source of the highly-collimated outflow NGC 2264 G (Ward-Thompson, Eiroa, & Casali 1995; Margulis et al. 1990; Lada & Fich 1996), which lies well outside the extended CS cores. One of the new Class 0 candidates may be an intermediate-mass source associated with an H_2O maser, and the other object is a low-mass source which may be associated with a near-infrared jet, and possibly with a molecular outflow. We report accurate positions for the new Class 0 candidates, based on the SCUBA images, and present new SEDs for these sources, as well as for the brighter IRAS point sources. A portion of this work was performed while GWC held a President's Fellowship from the University of California. MB and GWC gratefully acknowledge financial support from MB's NSF CAREER Grant, AST97-9753229.

On the insignificance of Herschel's sunspot correlation

Science.gov (United States)

Love, Jeffrey J.

2013-08-01

We examine William Herschel's hypothesis that solar-cycle variation of the Sun's irradiance has a modulating effect on the Earth's climate and that this is, specifically, manifested as an anticorrelation between sunspot number and the market price of wheat. Since Herschel first proposed his hypothesis in 1801, it has been regarded with both interest and skepticism. Recently, reports have been published that either support Herschel's hypothesis or rely on its validity. As a test of Herschel's hypothesis, we seek to reject a null hypothesis of a statistically random correlation between historical sunspot numbers, wheat prices in London and the United States, and wheat farm yields in the United States. We employ binary-correlation, Pearson-correlation, and frequency-domain methods. We test our methods using a historical geomagnetic activity index, well known to be causally correlated with sunspot number. As expected, the measured correlation between sunspot number and geomagnetic activity would be an unlikely realization of random data; the correlation is "statistically significant." On the other hand, measured correlations between sunspot number and wheat price and wheat yield data would be very likely realizations of random data; these correlations are "insignificant." Therefore, Herschel's hypothesis must be regarded with skepticism. We compare and contrast our results with those of other researchers. We discuss procedures for evaluating hypotheses that are formulated from historical data.

Hi-GAL: The Herschel Infrared Galactic Plane Survey

OpenAIRE

Molinari, S.; Swinyard, B.; Bally, J.; Barlow, M.; Bernard, J.-P.; Martin, P.; Moore, T.; Noriega-Crespo, A.; Plume, R.; Testi, L.; Zavagno, A.; Abergel, A.; Ali, B.; André, P.; Baluteau, J.-P.

2010-01-01

Hi-GAL, the Herschel infrared Galactic Plane Survey, is an Open Time Key Project of the Herschel Space Observatory. It will make an unbiased photometric survey of the inner Galactic plane by mapping a 2° wide strip in the longitude range ∣l∣ < 60° in five wavebands between 70 μm and 500 μm. The aim of Hi-GAL is to detect the earliest phases of the formation of molecular clouds and high-mass stars and to use the optimum combination of Herschel wavelength coverage, sensitivity, mapping strategy...

AN ANALYSIS OF THE ENVIRONMENTS OF FU ORIONIS OBJECTS WITH HERSCHEL

Energy Technology Data Exchange (ETDEWEB)

Green, Joel D.; Evans, Neal J. II; Merello, Manuel [Department of Astronomy, The University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712-1205 (United States); Kospal, Agnes [European Space Agency (ESA/ESTEC), Keplerlaan 1, 2200-AG Noordwijk (Netherlands); Herczeg, Gregory [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Quanz, Sascha P. [Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland); Henning, Thomas; Bouwman, Jeroen [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Van Kempen, Tim A. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300-RA Leiden (Netherlands); Lee, Jeong-Eun [Department of Astronomy and Space Science, Kyung Hee University, Gyeonggi 446-701 (Korea, Republic of); Dunham, Michael M. [Department of Astronomy, Yale University, New Haven, CT (United States); Meeus, Gwendolyn [Departamento de Fisica Teorica, Universidad Autonoma de Madrid, Campus Cantoblanco (Spain); Chen, Jo-hsin [Jet Propulsion Laboratory, Pasadena, CA (United States); Guedel, Manuel; Liebhart, Armin [Department of Astrophysics, University of Vienna (Austria); Skinner, Stephen L., E-mail: joel@astro.as.utexas.edu [Center for Astrophysics and Space Astronomy (CASA), University of Colorado, Boulder, CO 80309-0389 (United States)

2013-08-01

We present Herschel-HIFI, SPIRE, and PACS 50-670 {mu}m imaging and spectroscopy of six FU Orionis-type objects and candidates (FU Orionis, V1735 Cyg, V1515 Cyg, V1057 Cyg, V1331 Cyg, and HBC 722), ranging in outburst date from 1936 to 2010, from the 'FOOSH' (FU Orionis Objects Surveyed with Herschel) program, as well as ancillary results from Spitzer Infrared Spectrograph and the Caltech Submillimeter Observatory. In their system properties (L{sub bol}, T{sub bol}, and line emission), we find that FUors are in a variety of evolutionary states. Additionally, some FUors have features of both Class I and II sources: warm continuum consistent with Class II sources, but rotational line emission typical of Class I, far higher than Class II sources of similar mass/luminosity. Combining several classification techniques, we find an evolutionary sequence consistent with previous mid-IR indicators. We detect [O I] in every source at luminosities consistent with Class 0/I protostars, much greater than in Class II disks. We detect transitions of {sup 13}CO (J{sub up} of 5-8) around two sources (V1735 Cyg and HBC 722) but attribute them to nearby protostars. Of the remaining sources, three (FU Ori, V1515 Cyg, and V1331 Cyg) exhibit only low-lying CO, but one (V1057 Cyg) shows CO up to J = 23 {yields} 22 and evidence for H{sub 2}O and OH emission, at strengths typical of protostars rather than T Tauri stars. Rotational temperatures for 'cool' CO components range from 20 to 81 K, for {approx} 10{sup 50} total CO molecules. We detect [C I] and [N II] primarily as diffuse emission.

Reengineering the picture archiving and communication system (PACS) process for digital imaging networks PACS.

Science.gov (United States)

Horton, M C; Lewis, T E; Kinsey, T V

1999-05-01

Prior to June 1997, military picture archiving and communications systems (PACS) were planned, procured, and installed with key decisions on the system, equipment, and even funding sources made through a research and development office called Medical Diagnostic Imaging Systems (MDIS). Beginning in June 1997, the Joint Imaging Technology Project Office (JITPO) initiated a collaborative and consultative process for planning and implementing PACS into military treatment facilities through a new Department of Defense (DoD) contract vehicle called digital imaging networks (DIN)-PACS. The JITPO reengineered this process incorporating multiple organizations and politics. The reengineered PACS process administered through the JITPO transformed the decision process and accountability from a single office to a consultative method that increased end-user knowledge, responsibility, and ownership in PACS. The JITPO continues to provide information and services that assist multiple groups and users in rendering PACS planning and implementation decisions. Local site project managers are involved from the outset and this end-user collaboration has made the sometimes difficult transition to PACS an easier and more acceptable process for all involved. Corporately, this process saved DoD sites millions by having PACS plans developed within the government and proposed to vendors second, and then having vendors respond specifically to those plans. The integrity and efficiency of the process have reduced the opportunity for implementing nonstandard systems while sharing resources and reducing wasted government dollars. This presentation will describe the chronology of changes, encountered obstacles, and lessons learned within the reengineering of the PACS process for DIN-PACS.

Three-dimensional dynamics of protostellar evolution

International Nuclear Information System (INIS)

Cook, T.L.

1977-06-01

A three-dimensional finite difference numerical methodology was developed for self-gravitating, rotating gaseous systems. The fully nonlinear equations for time-varying fluid dynamics are solved by high speed computer in a cylindrical coordinate system rotating with an instantaneous angular velocity, selected such that the net angular momentum relative to the rotating frame is zero. The time-dependent adiabatic collapse of gravitationally bound, rotating, protostellar clouds is studied for specified uniform and nonuniform initial conditions. Uniform clouds can form axisymmetric, rotating toroidal configurations. If the thermal pressure is high, nonuniform clouds can also collapse to axisymmetric toroids. For low thermal pressures, however, the collapsing cloud is unstable to initial perturbations. The fragmentation of protostellar clouds is investigated by studying the response of rotating, self-gravitating, equilibrium toroids to non-axisymmetric perturbations. The detailed evolution of the fragmenting toroid depends upon a non-dimensional function of the initial entropy, the total mass in the toroid, the angular velocity of rotation, and the number of perturbation wavelengths around the circumference of the toroid. For low and intermediate entropies, the configuration develops into co-rotating components with spiral streamers. In the spiral regions retrograde vortices are observed in some examples. For high levels of entropy, barred spirals can exist as intermediate states of the fragmentation

The Wasp-Waist Nebula: VLA Ammonia Observations of the Molecular Core Envelope In a Unique Class 0 Protostellar System

Science.gov (United States)

Wiseman, Jennifer

2010-01-01

The Wasp-Waist Nebula was discovered in the IRAC c2d survey of the Ophiuchus starforming clouds. It is powered by a well-isolated, low-luminosity, low-mass Class 0 object. Its weak outflow has been mapped in the CO (3-2) transition with the JCMT, in 2.12 micron H2 emission with WIRC (the Wide-Field Infrared Camera) on the Hale 5-meter, and, most recently, in six H2 mid-infrared lines with the IRS (InfraRed Spectrograph) on-board the Spitzer Space Telescope; possible jet twisting structure may be evidence of unique core dynamics. Here, we report results of recent VLA ammonia mapping observations of the dense gas envelope feeding the central core protostellar system. We describe the morphology, kinematics, and angular momentum characteristics of this unique system. The results are compared with the envelope structure deduced from IRAC 8-micron absorption of the PAH (polycyclic aromatic hydrocarbon) background emission from the cloud.

PAC research in biology

Energy Technology Data Exchange (ETDEWEB)

Chain, C. Y., E-mail: yamil@fisica.unlp.edu.ar [Universidad Nacional de La Plata, IFLP (Argentina); Ceolin, M. [Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas, Dto de Quimica, Fac. Cs. Exactas, UNLP (Argentina); Pasquevich, A. F. [Universidad Nacional de La Plata, IFLP (Argentina)

2008-01-15

In this paper possible applications of the Perturbed Angular Correlations (PAC) technique in Biology are considered. Previous PAC experiments in biology are globally analyzed. All the work that appears in the literature has been grouped in a few research lines, just to make the analysis and discussion easy. The commonly used radioactive probes are listed and the experimental difficulties are analyzed. We also report applications of {sup 181}Hf and {sup 111}In isotopes in life sciences other than their use in PAC. The possibility of extending these studies using the PAC technique is discussed.

The future of PACS

International Nuclear Information System (INIS)

Nagy, Paul G.

2007-01-01

How will the future of picture archiving and communication systems (PACS) look, and how will this future affect the practice of radiology? We are currently experiencing disruptive innovations that will force an architectural redesign, making the majority of today’s commercial PACS obsolete as the field matures and expands to include imaging throughout the medical enterprise. The common architecture used for PACS cannot handle the massive amounts of data being generated by even current versions of computed tomography and magnetic resonance scanners. If a PACS cannot handle today’s technology, what will happen as the field expands to encompass pathology imaging, cone-beam reconstruction, and multispectral imaging? The ability of these new technologies to enhance research and clinical care will be impaired if PACS architectures are not prepared to support them. In attempting a structured approach to predictions about the future of PACS, we offer projections about the technologies underlying PACS as well as the evolution of standards development and the changing needs of a broad range of medical imaging. Simplified models of the history of the PACS industry are mined for the assumptions they provide about future innovations and trends. The physicist frequently participates in or directs technical assessments for medical equipment, and many physicists have extended these activities to include imaging informatics. It is hoped that by applying these speculative but experienced-based predictions, the interested medical physicist will be better able to take the lead in setting information technology strategies that will help facilities not only prepare for the future but continue to enjoy the benefits of technological innovations without disruptive, expensive, and unexpected changes in architecture. A good PACS strategy can help accelerate the time required for innovations to go from the drawing board to clinical implementation.

Hier ist wahrhaftig ein Loch im Himmel. The NGC 1999 dark globule is not a globule

Science.gov (United States)

Stanke, T.; Stutz, A. M.; Tobin, J. J.; Ali, B.; Megeath, S. T.; Krause, O.; Linz, H.; Allen, L.; Bergin, E.; Calvet, N.; di Francesco, J.; Fischer, W. J.; Furlan, E.; Hartmann, L.; Henning, T.; Manoj, P.; Maret, S.; Muzerolle, J.; Myers, P. C.; Neufeld, D.; Osorio, M.; Pontoppidan, K.; Poteet, C. A.; Watson, D. M.; Wilson, T.

2010-07-01

The NGC 1999 reflection nebula features a dark patch with a size of 10 000 AU, which has been interpreted as a small, dense foreground globule and possible site of imminent star formation. We present Herschel PACS far-infrared 70 and 160 μm maps, which reveal a flux deficit at the location of the globule. We estimate the globule mass needed to produce such an absorption feature to be a few tenths to a few {M}⊙. Inspired by this Herschel observation, we obtained APEX LABOCA and SABOCA submillimeter continuum maps, and Magellan PANIC near-infrared images of the region. We do not detect a submillimer source at the location of the Herschel flux decrement; furthermore our observations place an upper limit on the mass of the globule of 2.4×10-2 {M}⊙. Indeed, the submillimeter maps appear to show a flux depression as well. Furthermore, the near-infrared images detect faint background stars that are less affected by extinction inside the dark patch than in its surroundings. We suggest that the dark patch is in fact a hole or cavity in the material producing the NGC 1999 reflection nebula, excavated by protostellar jets from the V 380 Ori multiple system. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASAThis publication includes data acquired with the Atacama Pathfinder Experiment (APEX; proposal E-082.F-9807 and E-284.C-5015). APEX is a collaboration between the Max-Planck-Institut für Radioastronomie, the European Southern Observatory, and the Onsala Space Observatory. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.Appendices A and B are only available in electronic form at http://www.aanda.org

Effect of PAC dosage in a pilot-scale PAC-MBR treating micro-polluted surface water.

Science.gov (United States)

Hu, Jingyi; Shang, Ran; Deng, Huiping; Heijman, Sebastiaan G J; Rietveld, Luuk C

2014-02-01

To address the water scarcity issue and advance the traditional drinking water treatment technique, a powdered activated carbon-amended membrane bioreactor (PAC-MBR) is proposed for micro-polluted surface water treatment. A pilot-scale study was carried out by initially dosing different amounts of PAC into the MBR. Comparative results showed that 2g/L performed the best among 0, 1, 2 and 3g/L PAC-MBR regarding organic matter and ammonia removal as well as membrane flux sustainability. 1g/L PAC-MBR exhibited a marginal improvement in pollutant removal compared to the non-PAC system. The accumulation of organic matter in the bulk mixture of 3g/L PAC-MBR led to poorer organic removal and severer membrane fouling. Molecular weight distribution of the bulk liquid in 2g/L PAC-MBR revealed the synergistic effects of PAC adsorption/biodegradation and membrane rejection on organic matter removal. Additionally, a lower amount of soluble extracellular polymer substances in the bulk can be secured in 21 days operation. Copyright © 2013 Elsevier Ltd. All rights reserved.

The Chemistry of Protostellar Jet-Disk Systems

Science.gov (United States)

Codella, Claudio

2017-11-01

The birth of a Sun-like star is a complex game played by several participants whose respective roles are not yet entirely clear. On the one hand, the star-to-be accretes matter from a collapsing envelope. The gravitational energy released in the process heats up the material surrounding the protostar, creating warm regions enriched by interstellar complex organic molecules (iCOMs, at least 6 atoms) called hot-corinos. On the other hand, the presence of angular momentum and magnetic fields leads to two consequences: (i) the formation of circumstellar disks; and (ii) substantial episodes of matter ejection, as e.g. collimated jets. Thanks to the combination of the high-sensitivities and high-angular resolu- tions provided by the advent of new telescopes such as ALMA and NOEMA, it is now possible to image in details the earliest stages of the Sun-like star formation, thus inspecting the inner ( effects connected with the accreting disk. In other words, it is time to study the protostellar jet-disk system as a whole. Several still unanswered questions can be addressed. What is the origin of the chemically enriched hot corinos: are they jet-driven shocked regions? What is the origin of the ejections: are they due to disk or stellar winds? Shocks are precious tool to attack these questions, given they enrich the gas phase with the species deposited onto the dust mantles and/or locked in the refractory dust cores. Basically, we have to deal with two kind of shocks: (i) high-velocity shocks produced by protostellar jets, and (ii) slow accretion shocks located close to the centrifugal barrier of the accretion disks. Both shocks are factories of iCOMs, which can be then efficiently used to follow both the kinematics and the chemistry of the inner protostellar systems. With this in mind, we will discuss recent results obtained in the framework of different observational campaigns at mm and sub-mm wavelengths.

Fitting PAC spectra with stochastic models: PolyPacFit

Energy Technology Data Exchange (ETDEWEB)

Zacate, M. O., E-mail: zacatem1@nku.edu [Northern Kentucky University, Department of Physics and Geology (United States); Evenson, W. E. [Utah Valley University, College of Science and Health (United States); Newhouse, R.; Collins, G. S. [Washington State University, Department of Physics and Astronomy (United States)

2010-04-15

PolyPacFit is an advanced fitting program for time-differential perturbed angular correlation (PAC) spectroscopy. It incorporates stochastic models and provides robust options for customization of fits. Notable features of the program include platform independence and support for (1) fits to stochastic models of hyperfine interactions, (2) user-defined constraints among model parameters, (3) fits to multiple spectra simultaneously, and (4) any spin nuclear probe.

PACS for imaging centers.

Science.gov (United States)

Farnsworth, T J

2003-01-01

PACS can be a difficult and confusing decision for any radiology provider, but it can be an even more dynamic question for an outpatient imaging center. Every center represents a unique situation and requires a specialized solution. Typically, most of what is said and discussed about PACS concentrates on solutions and requirements for hospital radiology facilities. Administrators of imaging centers have different problems from hospital administrators, and they need different answers. For imaging centers, the financial justification for PACS may be less immediate than for hospitals. The first thing that must be understood is that no PAC system can make a typical imaging center completely filmless, at least not for quite a while. A hospital has the ability to dictate to its internal referring physicians how a radiological study is delivered, whereas in an imaging center environment, the roles are very much reversed. Once the justification are made for the financial viability of PACS in an imaging center, the next question is how to finance the acquisition of PACS. The decision will depend on how you cost justify your PACS, as well as the shape of your business model, and it will come to a decision between capital purchase or contracting with an application service provider, or ASP. Historically, in the hospital-dominated marketplace, PAC systems have been treated as capital acquisitions. However, for most imaging center, owning the system is more of a problem than a benefit. ASPs increasingly represent a successful alternative for imaging centers. One of the biggest things to consider with PACS is how to store all of those images. There are typically two options, on-site and off-site, with a new "hybrid" option surfacing more recently. Each option has benefits for the user, but the benefits of off-site storage are increasing as the technology advances. Some of the benefits are data security and access. Other issues to address are HIPAA compliance, standardized

Protostellar formation in rotating interstellar clouds. VI. Nonuniform initial conditions

International Nuclear Information System (INIS)

Boss, A.P.

1987-01-01

The collapse and fragmentation of rotating protostellar clouds is explored, starting from nonuniform density and nonuniform rotation initial conditions. Whether binary fragmentation occurs during the first dynamic collapse phase depends strongly on the initial density profile. Exponential clouds are only somewhat more resistant to fragmentation than uniform-density clouds, but power-law clouds do not undergo fragmentation for likely values of a relevant parameter. Because binary fragments start from profiles intermediate between uniform density and exponential clouds, minimum protostellar mass for population I stars should be increased to approximately 0.02 solar mass. The axisymmetric Terey et al. (1984) model should be stable with respect to nonaxisymmetric perturbations. Considering the observed binary frequency, collapse from power-law initial conditions appears to be less common than collapse from more uniform initial conditions. 34 references

INFRARED AND RADIO OBSERVATIONS OF A SMALL GROUP OF PROTOSTELLAR OBJECTS IN THE MOLECULAR CORE, L1251-C

Energy Technology Data Exchange (ETDEWEB)

Kim, Jungha; Lee, Jeong-Eun [School of Space Research, Kyung Hee University, Yongin-Si, Gyeonggi-Do 446-701 (Korea, Republic of); Choi, Minho; Kang, Miju [Korea Astronomy and Space Science Institute, 776 Daedeokdaero, Yuseong, Daejeon 305-348 (Korea, Republic of); Bourke, Tyler L. [Square Kilometre Array Organisation, Jodrell Bank Observatory, Lower Withington, Cheshire SK11 9DL (United Kingdom); II, Neal J. Evans [Department of Astronomy, University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712-1205 (United States); Francesco, James Di [National Research Council Canada, Herzberg Institute of Astrophysics, Victoria, BC (Canada); Cieza, Lucas A. [Universidad Diego Portales, Facultad de Ingeniera, Av. Ejército 441, Santiago (Chile); Dunham, Michael M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2015-05-15

We present a multi-wavelength observational study of a low-mass star-forming region, L1251-C, with observational results at wavelengths from the near-infrared to the millimeter. Spitzer Space Telescope observations confirmed that IRAS 22343+7501 is a small group of protostellar objects. The extended emission in the east–west direction with its intensity peak at the center of L1251A has been detected at 350 and 850 μm with the Caltech Submillimeter Observatory and James Clerk Maxwell telescopes, tracing dense envelope material around L1251A. The single-dish data from the Korean VLBI Network and TRAO telescopes show inconsistencies between the intensity peaks of several molecular emission lines and that of the continuum emission, suggesting complex distributions of molecular abundances around L1251A. The Submillimeter Array interferometer data, however, show intensity peaks of CO 2–1 and {sup 13}CO 2–1 located at the position of IRS 1, which is both the brightest source in the Infrared Array Camera image and the weakest source in the 1.3 mm dust-continuum map. IRS 1 is the strongest candidate for the driving source of the newly detected compact CO 2–1 outflow. Over the entire region (14′ × 14′) of L125l-C, 3 Class I and 16 Class II sources have been detected, including three young stellar objects (YSOs) in L1251A. A comparison between the average projected distance among the 19 YSOs in L1251-C and that among the 3 YSOs in L1251A suggests that L1251-C is an example of low-mass cluster formation where protostellar objects form in a small group.

PacCYP707A2 negatively regulates cherry fruit ripening while PacCYP707A1 mediates drought tolerance.

Science.gov (United States)

Li, Qian; Chen, Pei; Dai, Shengjie; Sun, Yufei; Yuan, Bing; Kai, Wenbin; Pei, Yuelin; He, Suihuan; Liang, Bin; Zhang, Yushu; Leng, Ping

2015-07-01

Sweet cherry is a non-climacteric fruit and its ripening is regulated by abscisic acid (ABA) during fruit development. In this study, four cDNAs (PacCYP707A1-4) encoding 8'-hydroxylase, a key enzyme in the oxidative catabolism of ABA, were identified in sweet cherry fruits using tobacco rattle virus-induced gene silencing (VIGS) and particle bombardment approaches. Quantitative real-time PCR confirmed significant down-regulation of target gene transcripts in VIGS-treated cherry fruits. In PacCYP707A2-RNAi-treated fruits, ripening and fruit colouring were promoted relative to control fruits, and both ABA accumulation and PacNCED1 transcript levels were up-regulated by 140%. Silencing of PacCYP707A2 by VIGS significantly altered the transcripts of both ABA-responsive and ripening-related genes, including the ABA metabolism-associated genes NCED and CYP707A, the anthocyanin synthesis genes PacCHS, PacCHI, PacF3H, PacDFR, PacANS, and PacUFGT, the ethylene biosynthesis gene PacACO1, and the transcription factor PacMYBA. The promoter of PacMYBA responded more strongly to PacCYP707A2-RNAi-treated fruits than to PacCYP707A1-RNAi-treated fruits. By contrast, silencing of PacCYP707A1 stimulated a slight increase in fruit colouring and enhanced resistance to dehydration stress compared with control fruits. These results suggest that PacCYP707A2 is a key regulator of ABA catabolism that functions as a negative regulator of fruit ripening, while PacCYP707A1 regulates ABA content in response to dehydration during fruit development. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

A strategic PACS maturity approach

NARCIS (Netherlands)

van de Wetering, R.

2011-01-01

Finding the key determinants of Picture Archivingand Communication Systems (PACS)performance in hospitals has been a conundrumfor decades. This research provides a method toassess the strategic alignment of PACS in hospitalsin order to find these key determinants. PACS touches upon every single part

OH far-infrared emission from low- and intermediate-mass protostars surveyed with Herschel-PACS

DEFF Research Database (Denmark)

Wampfler, Susanne Franziska; Bruderer, S.; Karska, A.

2013-01-01

fluxes nor their broad line widths, strongly suggesting an outflow origin. Slab excitation models indicate that the observed excitation temperature can either be reached if the OH molecules are exposed to a strong far-infrared continuum radiation field or if the gas temperature and density...... are sufficiently high. Using realistic source parameters and radiation fields, it is shown for the case of Ser SMM1 that radiative pumping plays an important role in transitions arising from upper level energies higher than 300 K. The compact emission in the low-mass sources and the required presence of a strong...

The effects of protostellar jet feedback on turbulent collapse

Science.gov (United States)

Murray, Daniel; Goyal, Shivam; Chang, Philip

2018-03-01

We present results of hydrodynamic simulations of massive star-forming regions with and without protostellar jets. We show that jets change the normalization of the stellar mass accretion rate, but do not strongly affect the dynamics of star formation. In particular, M*(t) ∝ f2(t - t*)2, where f = 1 - fjet is the fraction of mass accreted on to the protostar, fjet is the fraction ejected by the jet, and (t - t*)2 is the time elapsed since the formation of the first star. The star formation efficiency is non-linear in time. We find that jets have only a small effect (of order 25 per cent) on the accretion rate on to the protostellar disc (the `raw' accretion rate). We show that the small-scale structures - the radial density, velocity, and mass accretion profiles - are very similar in the jet and no-jet cases. Finally, we show that the inclusion of jets does drive turbulence but only on small (parsec) scales.

DIGGING INTO NGC 6334 I(N): MULTIWAVELENGTH IMAGING OF A MASSIVE PROTOSTELLAR CLUSTER

International Nuclear Information System (INIS)

Brogan, C. L.; Hunter, T. R.; Indebetouw, R.; Cyganowski, C. J.; Beuther, H.; Menten, K. M.; Thorwirth, S.

2009-01-01

We present a high-resolution, multi-wavelength study of the massive protostellar cluster NGC 6334 I(N) that combines new spectral line data from the Submillimeter Array (SMA) and VLA with a re-analysis of archival VLA continuum data, Two Micron All Sky Survey and Spitzer images. As shown previously, the brightest 1.3 mm source SMA1 contains substructure at subarcsecond resolution, and we report the first detection of SMA1b at 3.6 cm along with a new spatial component at 7 mm (SMA1d). We find SMA1 (aggregate of sources a, b, c, and d) and SMA4 to be comprised of free-free and dust components, while SMA6 shows only dust emission. Our 1.''5 resolution 1.3 mm molecular line images reveal substantial hot-core line emission toward SMA1 and to a lesser degree SMA2. We find CH 3 OH rotation temperatures of 165 ± 9 K and 145 ± 12 K for SMA1 and SMA2, respectively. We estimate a diameter of 1400 AU for the SMA1 hot-core emission, encompassing both SMA1b and SMA1d, and speculate that these sources comprise a ∼>800 AU separation binary that may explain the previously suggested precession of the outflow emanating from the SMA1 region. Compact line emission from SMA4 is weak, and none is seen toward SMA6. The LSR velocities of SMA1, SMA2, and SMA4 all differ by 1-2 km s -1 . Outflow activity from SMA1, SMA2, SMA4, and SMA6 is observed in several molecules including SiO(5-4) and IRAC 4.5 μm emission; 24 μm emission from SMA4 is also detected. Eleven water maser groups are detected, eight of which coincide with SMA1, SMA2, SMA4, and SMA6, while two others are associated with the Sandell source SM2. We also detect a total of 83 Class I CH 3 OH 44 GHz maser spots which likely result from the combined activity of many outflows. Our observations paint the portrait of multiple young hot cores in a protocluster prior to the stage where its members become visible in the near-infrared.

PACS administrators' and radiologists' perspective on the importance of features for PACS selection.

Science.gov (United States)

Joshi, Vivek; Narra, Vamsi R; Joshi, Kailash; Lee, Kyootai; Melson, David

2014-08-01

Picture archiving and communication systems (PACS) play a critical role in radiology. This paper presents the criteria important to PACS administrators for selecting a PACS. A set of criteria are identified and organized into an integrative hierarchical framework. Survey responses from 48 administrators are used to identify the relative weights of these criteria through an analytical hierarchy process. The five main dimensions for PACS selection in order of importance are system continuity and functionality, system performance and architecture, user interface for workflow management, user interface for image manipulation, and display quality. Among the subdimensions, the highest weights were assessed for security, backup, and continuity; tools for continuous performance monitoring; support for multispecialty images; and voice recognition/transcription. PACS administrators' preferences were generally in line with that of previously reported results for radiologists. Both groups assigned the highest priority to ensuring business continuity and preventing loss of data through features such as security, backup, downtime prevention, and tools for continuous PACS performance monitoring. PACS administrators' next high priorities were support for multispecialty images, image retrieval speeds from short-term and long-term storage, real-time monitoring, and architectural issues of compatibility and integration with other products. Thus, next to ensuring business continuity, administrators' focus was on issues that impact their ability to deliver services and support. On the other hand, radiologists gave high priorities to voice recognition, transcription, and reporting; structured reporting; and convenience and responsiveness in manipulation of images. Thus, radiologists' focus appears to be on issues that may impact their productivity, effort, and accuracy.

Water deuteration in star-forming regions: Contribution of Herschel/HIFI spectroscopic data

International Nuclear Information System (INIS)

Coutens, Audrey

2012-01-01

Water (H_2O) is one of the most abundant molecules in the interstellar medium. In addition to being a primordial ingredient in the emergence of life, this species plays an essential role in the process of star formation through the cooling of warm gas. It also controls the chemistry for many species, either in the gas phase or on the grain surfaces. Studying its deuterated form HDO is a unique opportunity, through the estimation of the HDO/H_2O ratio, to constrain the mechanisms of water formation and to better understand the origin of water contained in terrestrial oceans. Indeed, recent results obtained with the Herschel satellite show that the HDO/H_2O ratio observed in comets is similar to the value measured in oceans (∼1.5 10"-"4), which suggests that comets could have brought a large fraction to Earth to form the oceans during heavy bombardments (Hartogh et al. 2011). In this thesis, I was interested in the study of deuterated water in the first stages of star formation, the Class 0 stage, which precede the formation of the protoplanetary disk leading to the birth of comets and planets. Through a 1D non-Local Thermodynamic Equilibrium radiative transfer modeling of the line profiles of the numerous HDO and H_2"1"8O transitions detected with the HIFI (Heterodyne Instrument for Far-Infrared) instrument onboard the Herschel Space Observatory and ground-based telescopes (IRAM, JCMT), I determined that the HDO/H_2O ratios of the solar-type protostar IRAS 16293-2422 was about 2% in the hot corino, the inner part of the protostellar envelope sufficiently warm (T ≥ 100 K) to desorb in gas phase the water molecules trapped in the icy grain mantles, and about 0.5% in the colder part of the envelope. This study (Coutens et al. 2012) also allowed me to show that an absorbing layer rich in water surrounds the protostar. This layer could be produced by the photo-desorption through the UV field of the water molecules frozen on the grains, on the edges of the molecular

History of PACS in Asia

International Nuclear Information System (INIS)

Inamura, Kiyonari; Kim, Jong Hyo

2011-01-01

First, history of PACS (picture archiving and communication system for medical use) in Japan is described in two parts: in part 1, the early stage of PACS development from 1984 to 2002, and in part 2 the matured stage from 2002 to 2010. PACS in Japan has been developed and installed by local manufacturers by their own technology and demand from domestic hospitals. Part 1 mainly focuses on quantitative growth and part 2 on qualitative change. In part 2, integration of PACS into RIS (radiology information system), HIS (hospital information system), EPR (electronic patient record), teleradiology and IHE (integrating healthcare enterprise) is reported. Interaction with other elements of technology such as moving picture network system and three dimensional display is also discussed. Present situation of main 4 large size hospitals is presented. Second, history of PACS in Korea is reported. Very acute climbing up of filmless PACS diffusion was observed from 1997 to 2000. The reasons for such evolution are described and discussed. Also changes of PACS installation and system integration with other systems such as HIS and role of them in radiological diagnoses in Korea since 2002 are described. Third, history in China is investigated by checking international academic journals in English and described as far as events are logically linked and consistently meaningful.

Properties of the Irregular Satellite System around Uranus Inferred from K2, Herschel, and Spitzer Observations

Science.gov (United States)

Farkas-Takács, A.; Kiss, Cs.; Pál, A.; Molnár, L.; Szabó, Gy. M.; Hanyecz, O.; Sárneczky, K.; Szabó, R.; Marton, G.; Mommert, M.; Szakáts, R.; Müller, T.; Kiss, L. L.

2017-09-01

In this paper, we present visible-range light curves of the irregular Uranian satellites Sycorax, Caliban, Prospero, Ferdinand, and Setebos taken with the Kepler Space Telescope over the course of the K2 mission. Thermal emission measurements obtained with the Herschel/PACS and Spitzer/MIPS instruments of Sycorax and Caliban were also analyzed and used to determine size, albedo, and surface characteristics of these bodies. We compare these properties with the rotational and surface characteristics of irregular satellites in other giant planet systems and also with those of main belt and Trojan asteroids and trans-Neptunian objects. Our results indicate that the Uranian irregular satellite system likely went through a more intense collisional evolution than the irregular satellites of Jupiter and Saturn. Surface characteristics of Uranian irregular satellites seem to resemble the Centaurs and trans-Neptunian objects more than irregular satellites around other giant planets, suggesting the existence of a compositional discontinuity in the young solar system inside the orbit of Uranus.

Properties of the Irregular Satellite System around Uranus Inferred from K2 , Herschel , and Spitzer Observations

Energy Technology Data Exchange (ETDEWEB)

Farkas-Takács, A.; Kiss, Cs.; Pál, A.; Molnár, L.; Szabó, Gy. M.; Hanyecz, O.; Sárneczky, K.; Szabó, R.; Marton, G.; Szakáts, R.; Kiss, L. L. [Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Konkoly Thege Miklós út 15-17, H-1121 Budapest (Hungary); Mommert, M. [Department of Physics and Astronomy, Northern Arizona University, P.O. Box 6010, Flagstaff, AZ 86011 (United States); Müller, T., E-mail: farkas.aniko@csfk.mta.hu [Max-Plank-Institut für extraterrestrsiche Pyhsik, Garching (Germany)

2017-09-01

In this paper, we present visible-range light curves of the irregular Uranian satellites Sycorax, Caliban, Prospero, Ferdinand, and Setebos taken with the Kepler Space Telescope over the course of the K2 mission. Thermal emission measurements obtained with the Herschel /PACS and Spitzer /MIPS instruments of Sycorax and Caliban were also analyzed and used to determine size, albedo, and surface characteristics of these bodies. We compare these properties with the rotational and surface characteristics of irregular satellites in other giant planet systems and also with those of main belt and Trojan asteroids and trans-Neptunian objects. Our results indicate that the Uranian irregular satellite system likely went through a more intense collisional evolution than the irregular satellites of Jupiter and Saturn. Surface characteristics of Uranian irregular satellites seem to resemble the Centaurs and trans-Neptunian objects more than irregular satellites around other giant planets, suggesting the existence of a compositional discontinuity in the young solar system inside the orbit of Uranus.

HERSCHEL OBSERVATIONS OF GAS AND DUST IN THE UNUSUAL 49 Ceti DEBRIS DISK

Energy Technology Data Exchange (ETDEWEB)

Roberge, A. [Exoplanets and Stellar Astrophysics Laboratory, NASA Goddard Space Flight Center, Code 667, Greenbelt, MD 20771 (United States); Kamp, I. [Kapteyn Astronomical Institute, University of Groningen, 9700 AV Groningen (Netherlands); Montesinos, B. [Departamento de Astrofisica, Centro de Astrobiologia (INTA-CSIC), ESAC Campus, PO Box 78, E-28691 Villanueva de la Canada, Madrid (Spain); Dent, W. R. F. [ALMA, Avda Apoquindo 3846, Piso 19, Edificio Alsacia, Las Condes, Santiago (Chile); Meeus, G.; Eiroa, C. [Departmento Fisica Teorica, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco, E-28049 Madrid (Spain); Donaldson, J. K. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Olofsson, J. [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117, Heidelberg (Germany); Moor, A. [Konkoly Observatory of the Hungarian Academy of Sciences, P.O. Box 67, H-1525 Budapest (Hungary); Augereau, J.-C.; Thi, W.-F. [UJF-Grenoble 1/CNRS-INSU, Institut de Planetologie et d' Astrophysique de Grenoble, UMR 5274, F-38041, Grenoble (France); Howard, C.; Sandell, G. [SOFIA-USRA, NASA Ames Research Center, Building N232, PO Box 1, Moffett Field, CA 94035 (United States); Ardila, D. R. [NASA Herschel Science Center, California Institute of Technology, 1200 E. California Blvd., Mail Stop 220-6, Pasadena, CA 91125 (United States); Woitke, P., E-mail: Aki.Roberge@nasa.gov [University of Vienna, Department of Astronomy, Tuerkenschanzstr. 17, A-1180, Vienna (Austria)

2013-07-01

We present far-IR/sub-mm imaging and spectroscopy of 49 Ceti, an unusual circumstellar disk around a nearby young A1V star. The system is famous for showing the dust properties of a debris disk, but the gas properties of a low-mass protoplanetary disk. The data were acquired with the Herschel Space Observatory PACS and SPIRE instruments, largely as part of the ''Gas in Protoplanetary Systems'' (GASPS) Open Time Key Programme. Disk dust emission is detected in images at 70, 160, 250, 350, and 500 {mu}m; 49 Cet is significantly extended in the 70 {mu}m image, spatially resolving the outer dust disk for the first time. Spectra covering small wavelength ranges centered on eight atomic and molecular emission lines were obtained, including [O I] 63 {mu}m and [C II] 158 {mu}m. The C II line was detected at the 5{sigma} level-the first detection of atomic emission from the disk. No other emission lines were seen, despite the fact that the O I line is the brightest one observed in Herschel protoplanetary disk spectra. We present an estimate of the amount of circumstellar atomic gas implied by the C II emission. The new far-IR/sub-mm data fills in a large gap in the previous spectral energy distribution (SED) of 49 Cet. A simple model of the new SED confirms the two-component structure of the disk: warm inner dust and cold outer dust that produces most of the observed excess. Finally, we discuss preliminary thermochemical modeling of the 49 Cet gas/dust disk and our attempts to match several observational results simultaneously. Although we are not yet successful in doing so, our investigations shed light on the evolutionary status of the 49 Cet gas, which might not be primordial gas but rather secondary gas coming from comets.

HERSCHEL-PACS OBSERVATIONS OF FAR-IR CO LINE EMISSION IN NGC 1068: HIGHLY EXCITED MOLECULAR GAS IN THE CIRCUMNUCLEAR DISK

Energy Technology Data Exchange (ETDEWEB)

Hailey-Dunsheath, S.; Sturm, E.; Gracia-Carpio, J.; Davies, R.; Poglitsch, A.; Contursi, A.; Genzel, R.; Lutz, D.; Tacconi, L.; De Jong, J. A. [Max-Planck-Institut fuer extraterrestrische Physik, Postfach 1312, D-85741 Garching (Germany); Fischer, J. [Naval Research Laboratory, Remote Sensing Division, 4555 Overlook Ave SW, Washington, DC 20375 (United States); Sternberg, A.; Mark, D. [Sackler School of Physics and Astronomy, Tel Aviv University, Ramat Aviv 69978 (Israel); Gonzalez-Alfonso, E. [Departamento de Fisica, Universidad de Alcala de Henares, 28871 Alcala de Henares, Madrid (Spain); Veilleux, S. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Verma, A., E-mail: shd@astro.caltech.edu [Department of Astrophysics, Oxford University, Oxford OX1 3RH (United Kingdom)

2012-08-10

We report the detection of far-IR CO rotational emission from the prototypical Seyfert 2 galaxy NGC 1068. Using Herschel-PACS, we have detected 11 transitions in the J{sub upper} = 14-30 (E{sub upper}/k{sub B} = 580-2565 K) range, all of which are consistent with arising from within the central 10'' (700 pc). The detected transitions are modeled as arising from two different components: a moderate-excitation (ME) component close to the galaxy systemic velocity and a high-excitation (HE) component that is blueshifted by {approx}80 km s{sup -1}. We employ a large velocity gradient model and derive n{sub H2} {approx} 10{sup 5.6} cm{sup -3}, T{sub kin} {approx} 170 K, and M{sub H2} {approx} 10{sup 6.7} M{sub Sun} for the ME component and n{sub H2} {approx} 10{sup 6.4} cm{sup -3}, T{sub kin} {approx} 570 K, and M{sub H2} {approx} 10{sup 5.6} M{sub Sun} for the HE component, although for both components the uncertainties in the density and mass are {+-}(0.6-0.9) dex. Both components arise from denser and possibly warmer gas than traced by low-J CO transitions, and the ME component likely makes a significant contribution to the mass budget in the nuclear region. We compare the CO line profiles with those of other molecular tracers observed at higher spatial and spectral resolution and find that the ME transitions are consistent with these lines arising in the {approx}200 pc diameter ring of material traced by H{sub 2} 1-0 S(1) observations. The blueshift of the HE lines may also be consistent with the bluest regions of this H{sub 2} ring, but a better kinematic match is found with a clump of infalling gas {approx}40 pc north of the active galactic nucleus (AGN). We consider potential heating mechanisms and conclude that X-ray- or shock heating of both components is viable, while far-UV heating is unlikely. We discuss the prospects of placing the HE component near the AGN and conclude that while the moderate thermal pressure precludes an association with the

MedPAC Data Book

Data.gov (United States)

U.S. Department of Health & Human Services — MedPACs Data Book is the result of discussions with congressional staff members regarding ways that MedPAC can better support them. Some of the information it...

Vendor neutral archive in PACS

International Nuclear Information System (INIS)

Agarwal, Tapesh Kumar; Sanjeev

2012-01-01

An archive is a location containing a collection of records, documents, or other materials of historical importance. An integral part of Picture Archiving and Communication System (PACS) is archiving. When a hospital needs to migrate a PACS vendor, the complete earlier data need to be migrated in the format of the newly procured PACS. It is both time and money consuming. To address this issue, the new concept of vendor neutral archive (VNA) has emerged. A VNA simply decouples the PACS and workstations at the archival layer. This is achieved by developing an application engine that receives, integrates, and transmits the data using the different syntax of a Digital Imaging and Communication in Medicine (DICOM) format. Transferring the data belonging to the old PACS to a new one is performed by a process called migration of data. In VNA, a number of different data migration techniques are available to facilitate transfer from the old PACS to the new one, the choice depending on the speed of migration and the importance of data. The techniques include simple DICOM migration, prefetch-based DICOM migration, medium migration, and the expensive non-DICOM migration. “Vendor neutral” may not be a suitable term, and “architecture neutral,” “PACS neutral,” “content neutral,” or “third-party neutral” are probably better and preferred terms. Notwithstanding this, the VNA acronym has come to stay in both the medical IT user terminology and in vendor nomenclature, and radiologists need to be aware of its impact in PACS across the globe

UNVEILING THE DETAILED DENSITY AND VELOCITY STRUCTURES OF THE PROTOSTELLAR CORE B335

Energy Technology Data Exchange (ETDEWEB)

Kurono, Yasutaka; Saito, Masao; Kamazaki, Takeshi; Morita, Koh-Ichiro; Kawabe, Ryohei, E-mail: yasutaka.kurono@nao.ac.jp [Chile Observatory, National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan)

2013-03-10

We present an observational study of the protostellar core B335 harboring a low-mass Class 0 source. The observations of the H{sup 13}CO{sup +}(J = 1-0) line emission were carried out using the Nobeyama 45 m telescope and Nobeyama Millimeter Array. Our combined image of the interferometer and single-dish data depicts detailed structures of the dense envelope within the core. We found that the core has a radial density profile of n(r){proportional_to}r {sup -p} and a reliable difference in the power-law indices between the outer and inner regions of the core: p Almost-Equal-To 2 for r {approx}> 4000 AU and p Almost-Equal-To 1.5 for r {approx}< 4000 AU. The dense core shows a slight overall velocity gradient of {approx}1.0 km s{sup -1} over the scale of 20, 000 AU across the outflow axis. We believe that this velocity gradient represents a solid-body-like rotation of the core. The dense envelope has a quite symmetrical velocity structure with a remarkable line broadening toward the core center, which is especially prominent in the position-velocity diagram across the outflow axis. The model calculations of position-velocity diagrams do a good job of reproducing observational results using the collapse model of an isothermal sphere in which the core has an inner free-fall region and an outer region conserving the conditions at the formation stage of a central stellar object. We derived a central stellar mass of {approx}0.1 M{sub Sun }, and suggest a small inward velocity, v{sub r{>=}r{sub i{sub n{sub f}}}}{approx}0 km s{sup -1} in the outer core at {approx}> 4000 AU. We concluded that our data can be well explained by gravitational collapse with a quasi-static initial condition, such as Shu's model, or by the isothermal collapse of a marginally critical Bonnor-Ebert sphere.

Current status and installation of dental PACS

International Nuclear Information System (INIS)

Park, Chang Seo; Kim, Kee Deog; Park, Hyok; Jeong, Ho Gul

2004-01-01

Picture Archiving and Communication System (PACS) is difficult to implement in the best of situations, but evidence is growing that the benefits are significant. The aims of this study are to analyze the current status of full PACS and establish successful installation standard of dental PACS. Materials and Methods were based on the investigation of current working status and installation standard of PACS, and observation of variable issues to installation of dental PACS. By September 30, 2004, full PACS implementations in their facilities were 88.1% in specialized general hospitals (37 installations out of total 42 hospitals), 59.8% in general hospitals (144 installations out of total 241 hospitals), 12.3% in medical hospitals (116 installations out of total 941 hospitals) and 3.6% in dental hospitals (4 installations out of total 110 hospitals). Only 4 university dental hospitals currently have installed and are operating full PACS. Major obstacle to wide spread of dental PACS is initial high investments. Clinical environments of dental PACS differed from medical situation. Because of characteristic dental practice, the initial investments for dental PACS are generally much greater than those of medical PACS. Also new economic crisis makes users scruple. The best way to overcome these limitations is to establish an economic installation standard for dental PACS. Also the clear technical communication between the customer and the supplier before both sides are committed to the obstacles are critical to its success.

History of PACS in Asia.

Science.gov (United States)

Inamura, Kiyonari; Kim, Jong Hyo

2011-05-01

First, history of PACS (picture archiving and communication system for medical use) in Japan is described in two parts: in part 1, the early stage of PACS development from 1984 to 2002, and in part 2 the matured stage from 2002 to 2010. PACS in Japan has been developed and installed by local manufacturers by their own technology and demand from domestic hospitals. Part 1 mainly focuses on quantitative growth and part 2 on qualitative change. In part 2, integration of PACS into RIS (radiology information system), HIS (hospital information system), EPR (electronic patient record), teleradiology and IHE (integrating healthcare enterprise) is reported. Interaction with other elements of technology such as moving picture network system and three dimensional display is also discussed. Present situation of main 4 large size hospitals is presented. Second, history of PACS in Korea is reported. Very acute climbing up of filmless PACS diffusion was observed from 1997 to 2000. The reasons for such evolution are described and discussed. Also changes of PACS installation and system integration with other systems such as HIS and role of them in radiological diagnoses in Korea since 2002 are described. Third, history in China is investigated by checking international academic journals in English and described as far as events are logically linked and consistently meaningful. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Wide field CO J = 3 → 2 mapping of the Serpens cloud core

DEFF Research Database (Denmark)

Dionatos, Odyssefs; Nisini, Brunella; Codella, Claudio

2010-01-01

Context. Outflows provide indirect means to gain insight into diverse star formation-associated phenomena. At the level of individual protostellar cores, both outflows and the intrinsic core properties can be used to study the mass accretion/ejection process of heavily embedded protostellar sources...... this homogeneous dataset for a single star-forming site. Methods. An area comprising 460″ × 230″ of the Serpens cloud core was mapped in 12CO J = 3 → 2 with the HARP-B heterodyne array at the James Clerk Maxwell Telescope; J = 3 → 2 observations are more sensitive tracers of hot outflow gas than lower...

Reliability issues in PACS

Science.gov (United States)

Taira, Ricky K.; Chan, Kelby K.; Stewart, Brent K.; Weinberg, Wolfram S.

1991-07-01

Reliability is an increasing concern when moving PACS from the experimental laboratory to the clinical environment. Any system downtime may seriously affect patient care. The authors report on the several classes of errors encountered during the pre-clinical release of the PACS during the past several months and present the solutions implemented to handle them. The reliability issues discussed include: (1) environmental precautions, (2) database backups, (3) monitor routines of critical resources and processes, (4) hardware redundancy (networks, archives), and (5) development of a PACS quality control program.

A Solution to the Protostellar Accretion Problem

OpenAIRE

Padoan, Paolo; Kritsuk, Alexei; Norman, Michael L.; Nordlund, Ake

2004-01-01

Accretion rates of order 10^-8 M_\\odot/yr are observed in young protostars of approximately a solar mass with evidence of circumstellar disks. The accretion rate is significantly lower for protostars of smaller mass, approximately proportional to the second power of the stellar mass, \\dot{M}_accr\\propto M^2. The traditional view is that the observed accretion is the consequence of the angular momentum transport in isolated protostellar disks, controlled by disk turbulence or self--gravity. Ho...

Velocity structure of protostellar envelopes: gravitational collapse and rotation

International Nuclear Information System (INIS)

Belloche, Arnaud

2002-01-01

Stars form from the gravitational collapse of pre-stellar condensations in molecular clouds. The major aim of this thesis is to compare the predictions of collapse models with observations of both very young (class 0) protostars and starless condensations in millimeter molecular lines. We wish to understand what determines the masses of forming stars and whether the initial conditions have an effect on the dynamical evolution of a condensation. Using a Monte-Carlo radiative transfer code, we analyze rotation and infall spectroscopic signatures to study the velocity structure of a sample of protostellar condensations. We show that the envelope of the class 0 protostar IRAM 04191 in the Taurus molecular cloud is undergoing both extended, subsonic infall and fast, differential rotation. We propose that the inner part of the envelope is a magnetically supercritical core in the process of decoupling from the ambient cloud still supported by the magnetic field. We suggest that the kinematical properties observed for IRAM 04191 are representative of the physical conditions characterizing isolated protostars shortly after point mass formation. On the other hand, a similar study for the pre-stellar condensations of the Rho Ophiuchi proto-cluster yields mass accretion rates that are an order of magnitude higher than in IRAM 04191. This suggests that individual protostellar collapse in clusters is induced by external disturbances. Moreover, we show that the condensations do not have time to orbit significantly through the proto-cluster gas before evolving into protostars and pre-main-sequence stars. This seems inconsistent with models which resort to dynamical interactions and competitive accretion to build up a mass spectrum comparable to the stellar initial mass function. We conclude that protostellar collapse is nearly spontaneous in regions of isolated star formation such as the Taurus cloud but probably strongly induced in proto-clusters. (author) [fr

The spectral appearance of solar-type collapsing protostellar clouds

International Nuclear Information System (INIS)

Bertout, C.; Yorke, H.W.

1978-04-01

In this paper, we review the spectral properties of collapsing protostellar clouds, based on radiative transfer computations in hydrodynamic protostar models. In the first section, the basic results of protostar evolution computations in spherically symmetric and axially symmetry geometries, as they pertain to the appearance of protostars, are briefly reviewed. In the second section, we discuss the continuum appearance of spherically symmetric protostars with various masses. Also, we present recent results for the continuum appearance of an axially symmetric protostellar cloud. The third section deals with the line formation problem and describes preliminary results for a OH molecule in an axially symmetric collapsing cloud. Then we review recent theoretical and observational results obtained for the last evolutionary phase of protostars, known as the YY Orionis phase, when the stellar core first becomes visible in the optical range. Some of the new results and conclusions presented here can be summarized as follows: Rotating collapsing clouds are in general less luminous and cooler than corresponding non-rotating clouds - due to the longer evolutionary time scale. Nevertheless, high resolution studies (resolution [de

Short history of PACS. Part I: USA

Energy Technology Data Exchange (ETDEWEB)

Huang, H.K., E-mail: hkhuang@aol.com [Departments of Radiology and Biomedical Engineering, University of Southern California (United States); Hong Kong Polytechnic University (Hong Kong); Shanghai Institute of Technical Physics, Chinese Academy of Sciences (China)

2011-05-15

This historical review covers the PACS development in the USA during the past 28 years from 1982 to 2010. General historical remarks of PACS and international scene in three stages from infancy, puberty to adolescence are presented. Early PACS development was mostly financed by the federal government including the National Institutes of Health (NIH) and the U.S. Army Medical Research and Materiel Command. PACS evolution went through several stages. The earliest stages included the definition of large-scale PACS, establishment of the DICOM and other standards, the development of some early key PACS related technologies, and PACS implementation strategies. The later stages were in the concept of enterprise PACS, IHE (Integrating the Healthcare Enterprise) workflow profiles, and ePR with image distribution. The current most excited accomplishment is in the development of the new field in medical imaging informatics. This review goes through these stages and events in the USA during these 28 years, whenever an event involved participants from other countries, the contributors are cited.

Short history of PACS. Part I: USA

International Nuclear Information System (INIS)

Huang, H.K.

2011-01-01

This historical review covers the PACS development in the USA during the past 28 years from 1982 to 2010. General historical remarks of PACS and international scene in three stages from infancy, puberty to adolescence are presented. Early PACS development was mostly financed by the federal government including the National Institutes of Health (NIH) and the U.S. Army Medical Research and Materiel Command. PACS evolution went through several stages. The earliest stages included the definition of large-scale PACS, establishment of the DICOM and other standards, the development of some early key PACS related technologies, and PACS implementation strategies. The later stages were in the concept of enterprise PACS, IHE (Integrating the Healthcare Enterprise) workflow profiles, and ePR with image distribution. The current most excited accomplishment is in the development of the new field in medical imaging informatics. This review goes through these stages and events in the USA during these 28 years, whenever an event involved participants from other countries, the contributors are cited.

Short history of PACS. Part I: USA.

Science.gov (United States)

Huang, H K

2011-05-01

This historical review covers the PACS development in the USA during the past 28 years from 1982 to 2010. General historical remarks of PACS and international scene in three stages from infancy, puberty to adolescence are presented. Early PACS development was mostly financed by the federal government including the National Institutes of Health (NIH) and the U.S. Army Medical Research and Materiel Command. PACS evolution went through several stages. The earliest stages included the definition of large-scale PACS, establishment of the DICOM and other standards, the development of some early key PACS related technologies, and PACS implementation strategies. The later stages were in the concept of enterprise PACS, IHE (Integrating the Healthcare Enterprise) workflow profiles, and ePR with image distribution. The current most excited accomplishment is in the development of the new field in medical imaging informatics. This review goes through these stages and events in the USA during these 28 years, whenever an event involved participants from other countries, the contributors are cited. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Footprint Database and web services for the Herschel space observatory

Science.gov (United States)

Verebélyi, Erika; Dobos, László; Kiss, Csaba

2015-08-01

Using all telemetry and observational meta-data, we created a searchable database of Herschel observation footprints. Data from the Herschel space observatory is freely available for everyone but no uniformly processed catalog of all observations has been published yet. As a first step, we unified the data model for all three Herschel instruments in all observation modes and compiled a database of sky coverage information. As opposed to methods using a pixellation of the sphere, in our database, sky coverage is stored in exact geometric form allowing for precise area calculations. Indexing of the footprints allows for very fast search among observations based on pointing, time, sky coverage overlap and meta-data. This enables us, for example, to find moving objects easily in Herschel fields. The database is accessible via a web site and also as a set of REST web service functions which makes it usable from program clients like Python or IDL scripts. Data is available in various formats including Virtual Observatory standards.

Who Invented the Word Asteroid: William Herschel or Stephen Weston?

Science.gov (United States)

Cunningham, Clifford J.; Orchiston, Wayne

2011-11-01

William Herschel made the first serious study of 1 Ceres and 2 Pallas in the year 1802. He was moved by their dissimilarities to the other planets to coin a new term to distinguish them. For this purpose he enlisted the aid of his good friends William Watson and Sir Joseph Banks. Watson gave him a long list of possible names, which Herschel rejected. With a lifetime of experience classifying and naming newly found objects in nature, Banks became the man both Erasmus Darwin (in 1781) and William Herschel (in 1802) turned to for sage advice in developing a new descriptive language. In the case of Ceres and Pallas, Banks turned the task over to his friend, the noted philologist Stephen Weston, FRS. It has recently been stated by a noted British historian that it was Weston - not Herschel - who coined the term 'asteroid' to collectively describe Ceres and Pallas. This claim is investigated, and parallels are drawn in the use of neologism in astronomy and botany.

INTERMEDIATE-MASS HOT CORES AT ∼500 AU: DISKS OR OUTFLOWS?

International Nuclear Information System (INIS)

Palau, Aina; Girart, Josep M.; Fuente, Asunción; Alonso-Albi, Tomás; Fontani, Francesco; Sánchez-Monge, Álvaro; Boissier, Jérémie; Piétu, Vincent; Neri, Roberto; Busquet, Gemma; Estalella, Robert; Zapata, Luis A.; Zhang, Qizhou; Ho, Paul T. P.; Audard, Marc

2011-01-01

Observations with the Plateau de Bure Interferometer in the most extended configuration toward two intermediate-mass star-forming regions, IRAS 22198+6336 and AFGL 5142, reveal the presence of several complex organic molecules at ∼500 AU scales, confirming the presence of hot cores in both regions. The hot cores are not rich in CN-bearing molecules, as often seen in massive hot cores, and are mainly traced by CH 3 CH 2 OH, (CH 2 OH) 2 , CH 3 COCH 3 , and CH 3 OH, with, additionally, CH 3 CHO, CH 3 OD, and HCOOD for IRAS 22198+6336, and C 6 H and O 13 CS for AFGL 5142. The emission of complex molecules is resolved down to sizes of ∼300 and ∼600 AU, for IRAS 22198+6336 and AFGL 5142, respectively, and most likely is tracing protostellar disks rather than flattened envelopes or toroids as is usually found. This is especially clear for the case of IRAS 22198+6336, where we detect a velocity gradient for all the mapped molecules perpendicular to the most chemically rich outflow of the region, yielding a dynamic mass ∼> 4 M ☉ . As for AFGL 5142, the hot core emission is resolved into two elongated cores separated ∼1800 AU. A detailed comparison of the complex molecule peaks to the new CO (2-1) data and H 2 O maser data from the literature suggests also that for AFGL 5142 the complex molecules are mainly associated with disks, except for a faint and extended molecular emission found to the west, which is possibly produced in the interface between one of the outflows and the dense surrounding gas.

HERSCHEL OBSERVATIONS OF MAJOR MERGER PAIRS AT z = 0: DUST MASS AND STAR FORMATION

International Nuclear Information System (INIS)

Cao, Chen; Xu, Cong Kevin; Lu, Nanyao; Mazzarella, Joe; Domingue, Donovan; Ronca, Joseph; Jacques, Allison; Buat, Veronique; Cheng, Yi-Wen; Gao, Yu; Huang, Jiasheng; Jarrett, Thomas H.; Lisenfeld, Ute; Sun, Wei-Hsin; Wu, Hong; Yun, Min S.

2016-01-01

We present Herschel PACS and SPIRE far-infrared (FIR) and submillimeter imaging observations for a large K-band selected sample of 88 close major-merger pairs of galaxies (H-KPAIRs) in 6 photometric bands (70, 100, 160, 250, 350, and 500 μm). Among 132 spiral galaxies in the 44 spiral–spiral (S+S) pairs and 44 spiral–elliptical (S+E) pairs, 113 are detected in at least 1 Herschel band. The star formation rate (SFR) and dust mass (M dust ) are derived from the IR SED fitting. The mass of total gas (M gas ) is estimated by assuming a constant dust-to-gas mass ratio of 0.01. Star-forming spiral galaxies (SFGs) in S+S pairs show significant enhancements in both specific star formation rate (sSFR) and star formation efficiency (SFE), while having nearly the same gas mass compared to control galaxies. On the other hand, for SFGs in S+E pairs, there is no significant sSFR enhancement and the mean SFE enhancement is significantly lower than that of SFGs in S+S pairs. This suggests an important role for the disk–disk collision in the interaction-induced star formation. The M gas of SFGs in S+E pairs is marginally lower than that of their counterparts in both S+S pairs and the control sample. Paired galaxies with and without interaction signs do not differ significantly in their mean sSFR and SFE. As found in previous works, this much larger sample confirms that the primary and secondary spirals in S+S pairs follow a Holmberg effect correlation on sSFR

The Footprint Database and Web Services of the Herschel Space Observatory

Science.gov (United States)

Dobos, László; Varga-Verebélyi, Erika; Verdugo, Eva; Teyssier, David; Exter, Katrina; Valtchanov, Ivan; Budavári, Tamás; Kiss, Csaba

2016-10-01

Data from the Herschel Space Observatory is freely available to the public but no uniformly processed catalogue of the observations has been published so far. To date, the Herschel Science Archive does not contain the exact sky coverage (footprint) of individual observations and supports search for measurements based on bounding circles only. Drawing on previous experience in implementing footprint databases, we built the Herschel Footprint Database and Web Services for the Herschel Space Observatory to provide efficient search capabilities for typical astronomical queries. The database was designed with the following main goals in mind: (a) provide a unified data model for meta-data of all instruments and observational modes, (b) quickly find observations covering a selected object and its neighbourhood, (c) quickly find every observation in a larger area of the sky, (d) allow for finding solar system objects crossing observation fields. As a first step, we developed a unified data model of observations of all three Herschel instruments for all pointing and instrument modes. Then, using telescope pointing information and observational meta-data, we compiled a database of footprints. As opposed to methods using pixellation of the sphere, we represent sky coverage in an exact geometric form allowing for precise area calculations. For easier handling of Herschel observation footprints with rather complex shapes, two algorithms were implemented to reduce the outline. Furthermore, a new visualisation tool to plot footprints with various spherical projections was developed. Indexing of the footprints using Hierarchical Triangular Mesh makes it possible to quickly find observations based on sky coverage, time and meta-data. The database is accessible via a web site http://herschel.vo.elte.hu and also as a set of REST web service functions, which makes it readily usable from programming environments such as Python or IDL. The web service allows downloading footprint data

Infall-driven protostellar accretion and the solution to the luminosity problem

DEFF Research Database (Denmark)

Padoan, Paolo; Haugbølle, Troels; Nordlund, Åke

2014-01-01

We investigate the role of mass infall in the formation and evolution of protostars. To avoid ad hoc initial and boundary conditions, we consider the infall resulting self-consistently from modeling the formation of stellar clusters in turbulent molecular clouds. We show that infall rates...... in turbulent clouds are comparable to accretion rates inferred from protostellar luminosities or measured in pre-main-sequence stars. They should not be neglected in modeling the luminosity of protostars and the evolution of disks, even after the embedded protostellar phase. We find large variations of infall...... rates from protostar to protostar, and large fluctuations during the evolution of individual protostars. In most cases, the infall rate is initially of order 10–5 M ☉ yr–1, and may either decay rapidly in the formation of low-mass stars, or remain relatively large when more massive stars are formed...

William and Caroline Herschel pioneers in late 18th-century astronomy

CERN Document Server

Hoskin, Michael

2013-01-01

This beautifully structured book presents the essentials of William and Caroline Herschel's pioneering achievements in late 18th-century astronomy. Michael Hoskin shows that William Herschel was the first observational cosmologist and one of the first observers to attack the sidereal universe beyond the solar system:Herschel built instruments far better than any being used at the royal observatory. Aided by his sister Caroline, he commenced a great systematic survey that led to his discovery of Uranus in 1781.Unlike observers before him, whose telescopes did not reveal them as astronomical obj

FORMATION AND RECONDENSATION OF COMPLEX ORGANIC MOLECULES DURING PROTOSTELLAR LUMINOSITY OUTBURSTS

International Nuclear Information System (INIS)

Taquet, Vianney; Wirström, Eva S.; Charnley, Steven B.

2016-01-01

During the formation of stars, the accretion of surrounding material toward the central object is thought to undergo strong luminosity outbursts followed by long periods of relative quiescence, even at the early stages of star formation when the protostar is still embedded in a large envelope. We investigated the gas-phase formation and recondensation of the complex organic molecules (COMs) di-methyl ether and methyl formate, induced by sudden ice evaporation processes occurring during luminosity outbursts of different amplitudes in protostellar envelopes. For this purpose, we updated a gas-phase chemical network forming COMs in which ammonia plays a key role. The model calculations presented here demonstrate that ion–molecule reactions alone could account for the observed presence of di-methyl ether and methyl formate in a large fraction of protostellar cores without recourse to grain-surface chemistry, although they depend on uncertain ice abundances and gas-phase reaction branching ratios. In spite of the short outburst timescales of about 100 years, abundance ratios of the considered species higher than 10% with respect to methanol are predicted during outbursts due to their low binding energies relative to water and methanol which delay their recondensation during cooling. Although the current luminosity of most embedded protostars would be too low to produce complex organics in the hot-core regions that are observable with current sub-millimetric interferometers, previous luminosity outburst events would induce the formation of COMs in extended regions of protostellar envelopes with sizes increasing by up to one order of magnitude

Formation and Recondensation of Complex Organic Molecules during Protostellar Luminosity Outbursts

Science.gov (United States)

Taquet, Vianney; Wirström, Eva S.; Charnley, Steven B.

2016-04-01

During the formation of stars, the accretion of surrounding material toward the central object is thought to undergo strong luminosity outbursts followed by long periods of relative quiescence, even at the early stages of star formation when the protostar is still embedded in a large envelope. We investigated the gas-phase formation and recondensation of the complex organic molecules (COMs) di-methyl ether and methyl formate, induced by sudden ice evaporation processes occurring during luminosity outbursts of different amplitudes in protostellar envelopes. For this purpose, we updated a gas-phase chemical network forming COMs in which ammonia plays a key role. The model calculations presented here demonstrate that ion-molecule reactions alone could account for the observed presence of di-methyl ether and methyl formate in a large fraction of protostellar cores without recourse to grain-surface chemistry, although they depend on uncertain ice abundances and gas-phase reaction branching ratios. In spite of the short outburst timescales of about 100 years, abundance ratios of the considered species higher than 10% with respect to methanol are predicted during outbursts due to their low binding energies relative to water and methanol which delay their recondensation during cooling. Although the current luminosity of most embedded protostars would be too low to produce complex organics in the hot-core regions that are observable with current sub-millimetric interferometers, previous luminosity outburst events would induce the formation of COMs in extended regions of protostellar envelopes with sizes increasing by up to one order of magnitude.

FORMATION AND RECONDENSATION OF COMPLEX ORGANIC MOLECULES DURING PROTOSTELLAR LUMINOSITY OUTBURSTS

Energy Technology Data Exchange (ETDEWEB)

Taquet, Vianney [Leiden Observatory, Leiden University, P.O. Box 9513, 2300-RA Leiden (Netherlands); Wirström, Eva S. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-439 92 Onsala (Sweden); Charnley, Steven B. [Astrochemistry Laboratory and The Goddard Center for Astrobiology, Mailstop 691, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20770 (United States)

2016-04-10

During the formation of stars, the accretion of surrounding material toward the central object is thought to undergo strong luminosity outbursts followed by long periods of relative quiescence, even at the early stages of star formation when the protostar is still embedded in a large envelope. We investigated the gas-phase formation and recondensation of the complex organic molecules (COMs) di-methyl ether and methyl formate, induced by sudden ice evaporation processes occurring during luminosity outbursts of different amplitudes in protostellar envelopes. For this purpose, we updated a gas-phase chemical network forming COMs in which ammonia plays a key role. The model calculations presented here demonstrate that ion–molecule reactions alone could account for the observed presence of di-methyl ether and methyl formate in a large fraction of protostellar cores without recourse to grain-surface chemistry, although they depend on uncertain ice abundances and gas-phase reaction branching ratios. In spite of the short outburst timescales of about 100 years, abundance ratios of the considered species higher than 10% with respect to methanol are predicted during outbursts due to their low binding energies relative to water and methanol which delay their recondensation during cooling. Although the current luminosity of most embedded protostars would be too low to produce complex organics in the hot-core regions that are observable with current sub-millimetric interferometers, previous luminosity outburst events would induce the formation of COMs in extended regions of protostellar envelopes with sizes increasing by up to one order of magnitude.

Picture archiving and communications systems (PACS)

International Nuclear Information System (INIS)

Huang, H.K.; Dwyer, S.J. III; Angus, W.M.; Capp, M.P.; Arenson, R.L.; Kangarloo, H.

1987-01-01

This special focus session discusses the current status of picture archiving and communication systems (PACS). The first presentation focuses on the technological advances in various PACS components. The second presentation concentrates on image archiving - what is required, what is available. The third talk is on the concept of a total digital radiology department in the past, the present, and the future. The fourth panelist discusses evaluating various imaging systems as PACS components for the intensive care unit. Finally, one hears about clinical experience with two operating PACS modules, one in pediatric radiology and the second in a coronary care unit

PACS on mobile devices

Science.gov (United States)

Parikh, Ashesh; Mehta, Nihal

2015-03-01

Recent advances in internet browser technologies makes it possible to incorporate advanced functionality of a traditional PACS for viewing DICOM medical images on standard web browsers without the need to pre-install any plug-ins, apps or software. We demonstrate some of the capabilities of standard web browsers setting the stage for a cloud-based PACS.

Quasar Feedback in the Ultraluminous Infrared Galaxy F11119+3257: Connecting the Accretion Disk Wind with the Large-scale Molecular Outflow

Science.gov (United States)

Veilleux, S.; Bolatto, A.; Tombesi, F.; Meléndez, M.; Sturm, E.; González-Alfonso, E.; Fischer, J.; Rupke, D. S. N.

2017-07-01

In Tombesi et al., we reported the first direct evidence for a quasar accretion disk wind driving a massive (>100 M ⊙ yr-1) molecular outflow. The target was F11119+3257, an ultraluminous infrared galaxy (ULIRG) with unambiguous type 1 quasar optical broad emission lines. The energetics of the accretion disk wind and molecular outflow were found to be consistent with the predictions of quasar feedback models where the molecular outflow is driven by a hot energy-conserving bubble inflated by the inner quasar accretion disk wind. However, this conclusion was uncertain because the mass outflow rate, momentum flux, and mechanical power of the outflowing molecular gas were estimated from the optically thick OH 119 μm transition profile observed with Herschel. Here, we independently confirm the presence of the molecular outflow in F11119+3257, based on the detection of ˜±1000 km s-1 blue- and redshifted wings in the CO(1-0) emission line profile derived from deep ALMA observations obtained in the compact array configuration (˜2.″8 resolution). The broad CO(1-0) line emission appears to be spatially extended on a scale of at least ˜7 kpc from the center. Mass outflow rate, momentum flux, and mechanical power of (80-200) {R}7-1 M ⊙ yr-1, (1.5-3.0) {R}7-1 L AGN/c, and (0.15-0.40)% {R}7-1 {L}{AGN}, respectively, are inferred from these data, assuming a CO-to-H2 conversion factor appropriate for a ULIRG (R 7 is the radius of the outflow normalized to 7 kpc, and L AGN is the AGN luminosity). These rates are time-averaged over a flow timescale of 7 × 106 yr. They are similar to the OH-based rates time-averaged over a flow timescale of 4 × 105 yr, but about a factor of 4 smaller than the local (“instantaneous” ≲105 yr) OH-based estimates cited in Tombesi et al. The implications of these new results are discussed in the context of time-variable quasar-mode feedback and galaxy evolution. The need for an energy-conserving bubble to explain the molecular outflow

The Detector Physics and Applications Center - DePAC

CERN Document Server

Plothow-Besch, H; Fiorini, C; Grupen, C; Hassard, J; Longoni, A; Walenta, Albert H

2001-01-01

A new project, the 'Detector Physics and Applications Center (DePAC)', is presented. DePAC is a general detector and sensor database, which is not application specific, on the Internet. DePAC collects and explains the physics, the technology and the application of a wide range of radiation detectors. DePAC also collects and describes information about noise problems, front-end electronics, data transfer, processing and storage. DePAC provides short write-ups and source code of all sorts of detector related software depending on availability. DePAC collects useful constants and properties of materials in an exhaustive series of tables and graphs. DePAC also acts as a point of contact for researchers and industry in an interdisciplinary way, e.g. in biology, in medicine, in materials research and in high energy or nuclear physics. Last but not least, DePAC aims to develop also into a virtual lecturing school and serves as a tutorial for students and all interested scientists.

The Detector Physics and Applications Center—DePAC

Science.gov (United States)

Plothow-Besch, H.; Besch, H.-J.; Fiorini, C.; Grupen, C.; Hassard, J.; Longoni, A.; Walenta, A. H.

2001-09-01

A new project, the "Detector Physics and Applications Center (DePAC)", is presented. DePAC is a general detector and sensor database, which is not application specific, on the Internet. DePAC collects and explains the physics, the technology and the application of a wide range of radiation detectors. DePAC also collects and describes information about noise problems, front-end electronics, data transfer, processing and storage. DePAC provides short write-ups and source code of all sorts of detector related software depending on availability. DePAC collects useful constants and properties of materials in an exhaustive series of tables and graphs. DePAC also acts as a point of contact for researchers and industry in an interdisciplinary way, e.g. in biology, in medicine, in materials research and in high energy or nuclear physics. Last but not least, DePAC aims to develop also into a virtual lecturing school and serves as a tutorial for students and all interested scientists.

The Detector Physics and Applications Center - DePAC

International Nuclear Information System (INIS)

Plothow-Besch, H.; Besch, H.-J.; Fiorini, C.; Grupen, C.; Hassard, J.; Longoni, A.; Walenta, A.H.

2001-01-01

A new project, the 'Detector Physics and Applications Center (DePAC)', is presented. DePAC is a general detector and sensor database, which is not application specific, on the Internet. DePAC collects and explains the physics, the technology and the application of a wide range of radiation detectors. DePAC also collects and describes information about noise problems, front-end electronics, data transfer, processing and storage. DePAC provides short write-ups and source code of all sorts of detector related software depending on availability. DePAC collects useful constants and properties of materials in an exhaustive series of tables and graphs. DePAC also acts as a point of contact for researchers and industry in an interdisciplinary way, e.g. in biology, in medicine, in materials research and in high energy or nuclear physics. Last but not least, DePAC aims to develop also into a virtual lecturing school and serves as a tutorial for students and all interested scientists

Enterprise imaging and multi-departmental PACS

International Nuclear Information System (INIS)

Bergh, Bjoern

2006-01-01

The aim of this review is to present the status of digital image acquisition and archiving outside of radiology and to describe the technical concepts and possibilities of how a ''radiology'' Picture Archiving and Communication System (PACS) can become a multi-departmental (MD-)PACS. First the principles of system integration technology are explained and illustrated by the description of a typical radiology system integration. Then four types of modality integration approaches are defined: the direct modality integration (Type-I), the integration via DICOM acquisition software (Type-II) the integration via specialised systems either with (Type-III) or without PACS connection (Type-IV). The last section is dedicated to the presentation of the PACS requirements of selected interdisciplinary modality types [Endoscopy, Ultrasound and Electrocardiography (ECG)] and clinical disciplines (Pathology, Dermatology, Ophthalmology and Cardiology), which are then compared with the technical possibilities of a MD-PACS. (orig.)

Trends in PACS architecture

International Nuclear Information System (INIS)

Bellon, Erwin; Feron, Michel; Deprez, Tom; Reynders, Reinoud; Van den Bosch, Bart

2011-01-01

Radiological Picture Archiving and Communication Systems (PACS) have only relatively recently become abundant. Many hospitals have made the transition to PACS about a decade ago. During that decade requirements and available technology have changed considerably. In this paper we look at factors that influence the design of tomorrow's systems, especially those in larger multidisciplinary hospitals. We discuss their impact on PACS architecture (a technological perspective) as well as their impact on radiology (a management perspective). We emphasize that many of these influencing factors originate outside radiology and that radiology has little impact on these factors. That makes it the more important for managers in radiology to be aware of architectural aspects and it may change cooperation of radiology with, among others, the hospital's central IT department.

A PACS maturity model: a systematic meta-analytic review on maturation and evolvability of PACS in the hospital enterprise.

NARCIS (Netherlands)

Wetering, R. van de; Batenburg, R.

2009-01-01

INTRODUCTION: With PACS and medical imaging technology maturing, the importance of organizational maturity and effective deployment of PACS in the hospital enterprise are becoming significant. OBJECTIVE: The objective of this paper is twofold. Firstly, PACS literature on maturity and evolvability in

PACS module image communication at UCLA

International Nuclear Information System (INIS)

Stewart, B.K.; Taira, R.K.; Cho, P.S.; Mankovich, N.J.

1987-01-01

The advent of the ACR-NEMA digital and communication standard for PACS implementation between imaging, storage and display devices may simplify the networking problems inherent to PACS in the future. However, since the ACR-NEMA interface has not been implemented in manufactured products, the components of a PACS at the present time use various network interface designs, requiring substantial effort in the area of hardware and software integration. Many communication systems are used for the PACS implementation in Pediatric Radiology at UCLA, including baseband, broadband, as well as various parallel-line interface protocols, e.g. GP-IB. A VAX 11/750 minicomputer serves as the host computer for the UCLA Pediatric Radiology PACS system. Communication between the many peripherals take place through the host computer, which acts as the central node. Several communication links have been established, primarily: host computer to other local computers, image processors, various peripherals (digitizers, storage media, etc.) and, of course, to the 512, 1024 and 2048 viewing stations

Current developments in departmental PACS for ultrasound.

Science.gov (United States)

Grenier, L E; Eng, P

1995-01-01

1. INTRODUCTION TO DEPARTMENTAL PACS. Full or partial Departmental PACS is generally taken to mean an image management system focused on serving the needs of a specific modality or modality application. It will provide a modality specific means of image acquisition, specialized redisplay of images, distribution, and local long term storage of images. A Departmental PACS can be considered in isolation or as a component in a distributed Radiology PACS which consists of one or more departmental work groups on a back bone, potentially with shared resources. 2. DEPARTMENTAL PACS Issues Implementation of a Departmental PACS requires an in-depth knowledge of departmental clinical practice and work flow in all affected areas in the department, including patient intake, image collection, data routing, retrieval of previous image data, reporting, and long term data management and storage. Optimization of modality specific image display systems requires significant involvement from representative physician users. System architectures and user interfaces must be flexible enough to support the span of variation in clinical practice encountered in the site. A departmental PACS should offer a variety of "open" communications interfaces, both local and wide area, recognizing that outreach efforts are often driven by specific imaging departments. Interfaces to other departmental PAC systems and other information systems must be considered in order to facilitate institutions developing "Best of Breed" PACS systems. As hospitals move toward the integrated electronic medical record, means need to exist for a client process launched from a physician desktop to acquire images and/or reports from a departmental system. At minimum, HIS/RIS interfaces need to be considered to minimize re-keying of data and reduce data entry errors. 3. DESIGN OBJECTIVES FOR ALI ULTRAPACS. The key objectives were to design a product which could function either as a free standing PACS or as a departmental

INTERMEDIATE-MASS HOT CORES AT {approx}500 AU: DISKS OR OUTFLOWS?

Energy Technology Data Exchange (ETDEWEB)

Palau, Aina; Girart, Josep M. [Institut de Ciencies de l' Espai (CSIC-IEEC), Campus UAB-Facultat de Ciencies, Torre C5-parell 2, 08193 Bellaterra, Catalunya (Spain); Fuente, Asuncion; Alonso-Albi, Tomas [Observatorio Astronomico Nacional, P.O. Box 112, 28803 Alcala de Henares, Madrid (Spain); Fontani, Francesco; Sanchez-Monge, Alvaro [Osservatorio Astrofisico di Arcetri, INAF, Largo E. Fermi 5, 50125 Firenze (Italy); Boissier, Jeremie [Istituto di Radioastronomia, INAF, Via Gobetti 101, Bologna (Italy); Pietu, Vincent; Neri, Roberto [IRAM, 300 Rue de la piscine, 38406 Saint Martin d' Heres (France); Busquet, Gemma [Istituto di Fisica dello Spazio Interplanetario, INAF, Area di Recerca di Tor Vergata, Via Fosso Cavaliere 100, 00133 Roma (Italy); Estalella, Robert [Departament d' Astronomia i Meteorologia (IEEC-UB), Institut Ciencies Cosmos, Universitat Barcelona, Marti Franques 1, 08028 Barcelona (Spain); Zapata, Luis A. [Centro de Radioastronomia y Astrofisica, Universidad Nacional Autonoma de Mexico, P.O. Box 3-72, 58090 Morelia, Michoacan (Mexico); Zhang, Qizhou; Ho, Paul T. P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Audard, Marc, E-mail: palau@ieec.uab.es [Geneva Observatory, University of Geneva, Ch. des Maillettes 51, 1290 Versoix (Switzerland)

2011-12-20

Observations with the Plateau de Bure Interferometer in the most extended configuration toward two intermediate-mass star-forming regions, IRAS 22198+6336 and AFGL 5142, reveal the presence of several complex organic molecules at {approx}500 AU scales, confirming the presence of hot cores in both regions. The hot cores are not rich in CN-bearing molecules, as often seen in massive hot cores, and are mainly traced by CH{sub 3}CH{sub 2}OH, (CH{sub 2}OH){sub 2}, CH{sub 3}COCH{sub 3}, and CH{sub 3}OH, with, additionally, CH{sub 3}CHO, CH{sub 3}OD, and HCOOD for IRAS 22198+6336, and C{sub 6}H and O{sup 13}CS for AFGL 5142. The emission of complex molecules is resolved down to sizes of {approx}300 and {approx}600 AU, for IRAS 22198+6336 and AFGL 5142, respectively, and most likely is tracing protostellar disks rather than flattened envelopes or toroids as is usually found. This is especially clear for the case of IRAS 22198+6336, where we detect a velocity gradient for all the mapped molecules perpendicular to the most chemically rich outflow of the region, yielding a dynamic mass {approx}> 4 M{sub Sun }. As for AFGL 5142, the hot core emission is resolved into two elongated cores separated {approx}1800 AU. A detailed comparison of the complex molecule peaks to the new CO (2-1) data and H{sub 2}O maser data from the literature suggests also that for AFGL 5142 the complex molecules are mainly associated with disks, except for a faint and extended molecular emission found to the west, which is possibly produced in the interface between one of the outflows and the dense surrounding gas.

PACS for the Developing World

Directory of Open Access Journals (Sweden)

Jeffrey B. Mendel

2015-11-01

Full Text Available Digital imaging is now firmly ensconced in the developed world. Its widespread adoption has enabled instant access to images, remote viewing, remote consultation, and the end of lost or misplaced film. Unfortunately, the current paradigm of Picture Archiving and Communication System (PACS, with advanced technology inseparable from high complexity, high purchase costs, and high maintenance costs, is not suited for the low-income developing world. Like the simple, easy to repair, 1950’s American cars still running on the streets of Havana, the developing world requires a PACS (DW-PACS that can perform basic functions and survive in a limited-resource environment. The purpose of this article is to more fully describe this concept and to present a blueprint for PACS tailored to the needs and resources of the developing world. This framework should assist both users looking for a vendor-supplied or open-source solutions and developers seeking to address the needs of this emerging market.

OT2_amoor_4: A census of debris disks in nearby young moving groups with Herschel.

Science.gov (United States)

Moór, A.

2011-09-01

Nearly all young stars harbour circumstellar disks, that serve as the reservoir for mass accretion onto the star, and later become the birthplace of planetary systems. After the disappearance of the gas component from the disk a dusty debris disk is formed that is believed to mark the location of the planetesimal belt as well. For outlining the evolution of such debris disks traditionally open clusters and field stars were studied, however we argue that the recently discovered young moving groups are more suitable objects for such analyses, due to their proximity and good coverage of the first 50 Myr period of the planetary system evolution. In this proposal we request 70/160 um Herschel/PACS photometric observations for so-far unobserved moving group members. These observations will provide a complete coverage of all known members within 80 pc of five nearby young moving groups (beta Pic Moving Group, Tucana-Horologium, Carina, Columba, and Argus), in the A to K spectral range. Based on the new observations we will identify new debris disks, characterize the disk population within individual moving groups, and study disk evolution by comparing the groups of different ages. The results will be used to verify predictions of the self-stirring model of the evolution of planetesimal disks. We will also compare the properties of debris disks in groups of the same age, looking for additional 'environmental' parameters that affect disk structure over a whole moving group. Our study will be a significant contribution to the census of debris disks in young moving groups, increasing the number of observed sources by a factor of 1.5. Since Spitzer could perform only a limited census and the so-far approved Herschel programs added very few additional moving group obervations, our programme is expected to have a high legacy value.

Searching the stars the story of Caroline Herschel

CERN Document Server

Ogilvie, Marilyn B

2011-01-01

Caroline Herschel is best known as the less significant sister of the astronomer William Herschel. Yet the romantic notion of her tirelessly working for her brother while he made his studies of the heavens, documenting his discoveries so he could achieve greatness in the scientific world, couldn't be further from the truth. When Caroline wasn't working as her brother's assistant, she was sweeping the stars with her own small telescope given to her by William. Not only did she unearth three important nebulae, but she discovered no fewer than eight comets in her own right. When William beca

Herschel SPIRE FTS spectral line source calibrators

DEFF Research Database (Denmark)

Hopwood, Rosalind; Polehampton, Edward; Valtchanov, Ivan

2015-01-01

We present a summary of the Herschel SPIRE/FTS calibration programme to monitor the repeatability of spectral lines. Observations of planetary nebulae and post-AGB stars are used to assess repeatability and model the asymmetry of the instrument line shape.......We present a summary of the Herschel SPIRE/FTS calibration programme to monitor the repeatability of spectral lines. Observations of planetary nebulae and post-AGB stars are used to assess repeatability and model the asymmetry of the instrument line shape....

Current status of the UCSF second-generation PACS

Science.gov (United States)

Huang, H. K.; Arenson, Ronald L.; Wong, Albert W. K.; Bazzill, Todd M.; Lou, Shyhliang A.; Andriole, Katherine P.; Wang, Jun; Zhang, Jianguo; Wong, Stephen T. C.

1996-05-01

This paper describes the current status of the second generation PACS at UCSF commenced in October 1992. The UCSF PACS is designed in-house as a hospital-integrated PACS based on an open architecture concept using industrial standards including UNIX operating system, C programming language, X-Window user interface, TCP/IP communication protocol, DICOM 3.0 image standard and HL7 health data format. Other manufacturer's PACS components which conform with these standards can be easily integrated into the system. Relevant data from HIS and RIS is automatically incorporated into the PACS using HL7 data format and TCP/IP communication protocol. The UCSF system also takes advantage of state-of-the-art communication, storage, and software technologies in ATM, multiple storage media, automatic programming, multilevel processes for a better cost-performance system. The primary PACS network is the 155 Mbits/sec OC3 ATM with the Ethernet as the back-up. The UCSF PACS also connects Mt. Zion Hospital and San Francisco VA Medical Center in the San Francisco Bay area via an ATM wide area network with a T1 line as the back-up. Currently, five MR and five CT scanners from multiple sites, two computed radiography systems, two film digitizers, one US PACS module, the hospital HIS and the department RIS have been connected to the PACS network. The image data is managed by a mirrored database (Sybase). The PACS controller, with its 1.3 terabyte optical disk library, acquires 2.5 gigabytes digital data daily. Four 2K, five, 1,600-line multiple monitor display workstations are on line in neuroradiology, pediatric radiology and intensive care units for clinical use. In addition, the PACS supports over 100 Macintosh users in the department and selected hospital sites for both images and textual retrieval through a client/server mechanism. We are also developing a computation and visualization node in the PACS network for advancing radiology research.

A DICOM based PACS for nuclear medicine; Ein DICOM-basiertes PACS fuer die Nuklearmedizin

Energy Technology Data Exchange (ETDEWEB)

Lassmann, M.; Reiners, C. [Wuerzburg Univ. (Germany). Klinik und Poliklinik fuer Nuklearmedizin

2002-02-01

The installation of a radiology information system (RIS) connected to a hospital information system (HIS) and a picture archiving and communications system (PACS) seems mandatory for a nuclear medicine department in order to guarantee a high patient throughput. With these systems a fast transmission of reports, images to the in- and out-patients' wards and private practitioners is realized. Therefore, since April 2000, at the department of nuclear medicine of the university of Wuerzburg a completely DICOM based PACS has been implemented in addition to the RIS. With this system a DICOM based workflow is realized throughout the department of nuclear medicine for reporting and archiving. The PACS is connected to six gamma-cameras, a PET scanner, a bone densitometry system and an ultrasound device. The volume of image data archived per month is 4 GByte. Patient demographics are provided to the modalities via DICOM-Worklist. With these PACS components a department specific archive purely based on DICOM can be realized. During the installation process problems occurred mainly because of the complex DICOM standard for nuclear medicine. Related to that is the problem that most of the software implementations still contain bugs or are not adapted to the needs of a nuclear medicine department (particularly for PET). A communication software for the distribution of nuclear medicine reports and images based on techniques used for the worldwide web is currently tested. (orig.) [German] Fuer eine nuklearmedizinische Klinik ist ein Klinikinformationssystem (KIS) gekoppelt mit einem Radiologieinformationssystem (RIS) sowie einem Bildarchivierungs- und Verteilungssystem (PACS) unabdingbar, um einen schnellen Patientendurchsatz sowie die zeitnahe Uebermittlung von Befunden inklusive nuklearmedizinischen Bildern an zuweisende Stationen, Ambulanzen und externe Zuweiser zu gewaehrleisten. Daher wurde im April 2000 an der Klinik und Poliklinik fuer Nuklearmedizin der Universitaet

observations of hot molecular gas emission from embedded low-mass protostars

DEFF Research Database (Denmark)

Visser, R.; Kristensen, L. E.; Bruderer, S.

2012-01-01

Aims. Young stars interact vigorously with their surroundings, as evident from the highly rotationally excited CO (up to Eu/k = 4000 K) and H2O emission (up to 600 K) detected by the Herschel Space Observatory in embedded low-mass protostars. Our aim is to construct a model that reproduces...... the observations quantitatively, to investigate the origin of the emission, and to use the lines as probes of the various heating mechanisms. Methods. The model consists of a spherical envelope with a power-law density structure and a bipolar outflow cavity. Three heating mechanisms are considered: passive heating...... such as luminosity and envelope mass. Results. The bulk of the gas in the envelope, heated by the protostellar luminosity, accounts for 3–10% of the CO luminosity summed over all rotational lines up to J = 40–39; it is best probed by low-J CO isotopologue lines such as C18O 2–1 and 3–2. The UV-heated gas and the C...

Formation of X-ray emitting stationary shocks in magnetized protostellar jets

Science.gov (United States)

Ustamujic, S.; Orlando, S.; Bonito, R.; Miceli, M.; Gómez de Castro, A. I.; López-Santiago, J.

2016-12-01

Context. X-ray observations of protostellar jets show evidence of strong shocks heating the plasma up to temperatures of a few million degrees. In some cases, the shocked features appear to be stationary. They are interpreted as shock diamonds. Aims: We investigate the physics that guides the formation of X-ray emitting stationary shocks in protostellar jets; the role of the magnetic field in determining the location, stability, and detectability in X-rays of these shocks; and the physical properties of the shocked plasma. Methods: We performed a set of 2.5-dimensional magnetohydrodynamic numerical simulations that modelled supersonic jets ramming into a magnetized medium and explored different configurations of the magnetic field. The model takes into account the most relevant physical effects, namely thermal conduction and radiative losses. We compared the model results with observations, via the emission measure and the X-ray luminosity synthesized from the simulations. Results: Our model explains the formation of X-ray emitting stationary shocks in a natural way. The magnetic field collimates the plasma at the base of the jet and forms a magnetic nozzle there. After an initial transient, the nozzle leads to the formation of a shock diamond at its exit which is stationary over the time covered by the simulations ( 40-60 yr; comparable with timescales of the observations). The shock generates a point-like X-ray source located close to the base of the jet with luminosity comparable with that inferred from X-ray observations of protostellar jets. For the range of parameters explored, the evolution of the post-shock plasma is dominated by the radiative cooling, whereas the thermal conduction slightly affects the structure of the shock. A movie is available at http://www.aanda.org

A 'private adventure'? John Herschel's Cape voyage and the production of the 'Cape Results'

Science.gov (United States)

Ruskin, Steven William

2002-07-01

This dissertation considers the life of John Herschel (1792 1871) from the years 1833 to 1847. In 1833 Herschel sailed from London to Cape Town, southern Africa, to undertake (at his own expense) an astronomical exploration of the southern heavens, as well as a terrestrial exploration of the area around Cape Town. After his return to England in 1838, he was highly esteemed and became Britain's most recognized scientist. In 1847 his southern hemisphere astronomical observations were published as the Cape Results. The main argument of this dissertation is that Herschel's voyage, and the publication of the Cape Results, in addition to their contemporary scientific importance, were also significant for nineteenth-century politics and culture. This dissertation is a two-part dissertation. The first part is entitled “John Herschel's Cape Voyage: Private Science, Public Imagination, and the Ambitions of Empire”; and the second part, “The Production of the Cape Results.” In the first part it is demonstrated that the reason for Herschel's cultural renown was the popular notion that his voyage to the Cape was a project aligned with the imperial ambitions of the British government. By leaving England for one of its colonies, and pursuing there a significant scientific project, Herschel was seen in the same light as other British men of science who had also undertaken voyages of exploration and discovery. It is then demonstrated, in the second part of this work, that the production of the Cape Results, in part because of Herschel's status as Britain's scientific figurehead, was a significant political and cultural event. In addition to the narrow area of Herschel scholarship, this dissertation touches on other areas of research in the history of science as well: science and culture, science and empire, science and politics, and what has been called the “new” history of scientific books.

Effect of powdered activated carbon (PAC) on MBR performance and effluent trihalomethane formation: At the initial stage of PAC addition.

Science.gov (United States)

Gao, Yue; Ma, Defang; Yue, Qinyan; Gao, Baoyu; Huang, Xia

2016-09-01

In this study, the MBR was used to treat municipal wastewater for reuse. Effects of powdered activated carbon (PAC) addition on MBR system in terms of effluent water quality, trihalomethane (THM) formation and membrane organic fouling tendency of MBR sludge supernatant at the initial stage of PAC addition were investigated. Effects of chlorine dose and contact time on THM formation and speciation were also studied. PAC addition enhanced the removal of organic matters, especially aromatic components, which improved the UV254 removal rate from 34% to 83%. PAC addition greatly reduced the membrane organic fouling tendency of MBR sludge supernatant. PAC addition reduced the MBR effluent trihalomethane formation potential (THMFP) from 351.29 to 241.95μg/L, while increased THM formation reactivity by 42%. PAC addition enhanced the formation of higher toxic bromine-containing THMs. High chlorine dose and contact time resulted in higher THM formation but lower proportion of bromine-containing THMs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Actual concepts of digital PAC-spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Roeder, J., E-mail: j.roeder@tu-bs.de; Herden, C., E-mail: cherden@viewplus.de [Braunschweig University of Technology, Institute of Physical and Theoretical Chemistry (Germany); Gardner, J. A., E-mail: john.gardner@viewplus.com [Oregon State University (United States); Becker, K. D., E-mail: k-d.becker@tu-bs.de [Braunschweig University of Technology, Institute of Physical and Theoretical Chemistry (Germany); Uhrmacher, M., E-mail: muhrmac@gwdg.de; Hofsaess, H., E-mail: hhofsae@uni-goettingen.de [University of Goettingen, II. Institute of Physics (Germany)

2008-01-15

In conventional perturbed angular correlation (PAC)-spectroscopy huge amounts of events are processed by fast electronics. Modern digital signal processing devices and the improvement in the computer technology in recent years allow today digital PAC-spectrometer setups capable to perform software-based data processing with all the benefits of storage, repeatable data analysis under different limits, and easy switching between different isotopes. In this paper we discuss experiences and concepts of a first realized digital PAC-spectrometer, which will be rebuild at ISOLDE/CERN/Geneva.

Picture archiving and communications systems (PACS): an introduction

International Nuclear Information System (INIS)

Schwartz, L.H.

2001-01-01

Picture Archiving and Communications Systems (PACS) has revolutionized the practice of radiology. PACS consist of a variety of electronic/computer components, and the connectivity between these components. PACS is an efficient means to transmit, store, retrieve and digitally display medical images

PCaPAC 2006 Proceedings

Energy Technology Data Exchange (ETDEWEB)

Pavel Chevtsov; Matthew Bickley (Eds.)

2007-03-30

The 6-th international PCaPAC (Personal Computers and Particle Accelerator Controls) workshop was held at Jefferson Lab, Newport News, Virginia, from October 24-27, 2006. The main objectives of the conference were to discuss the most important issues of the use of PCs and modern IT technologies for controls of accelerators and to give scientists, engineers, and technicians a forum to exchange the ideas on control problems and their solutions. The workshop consisted of plenary sessions and poster sessions. No parallel sessions were held.Totally, more than seventy oral and poster presentations as well as tutorials were made during the conference, on the basis of which about fifty papers were submitted by the authors and included in this publication. This printed version of the PCaPAC 2006 Proceedings is published at Jefferson Lab according to the decision of the PCaPAC International Program Committee of October 26, 2006.

Integration of computer-aided diagnosis/detection (CAD) results in a PACS environment using CAD-PACS toolkit and DICOM SR

International Nuclear Information System (INIS)

Le, Anh H.T.; Liu, Brent; Huang, H.K.

2009-01-01

Picture Archiving and Communication System (PACS) is a mature technology in health care delivery for daily clinical imaging service and data management. Computer-aided detection and diagnosis (CAD) utilizes computer methods to obtain quantitative measurements from medical images and clinical information to assist clinicians to assess a patient's clinical state more objectively. CAD needs image input and related information from PACS to improve its accuracy; and PACS benefits from CAD results online and available at the PACS workstation as a second reader to assist physicians in the decision making process. Currently, these two technologies remain as two separate independent systems with only minimal system integration. This paper describes a universal method to integrate CAD results with PACS in its daily clinical environment. The method is based on Health Level 7 (HL7) and Digital imaging and communications in medicine (DICOM) standards, and Integrating the Healthcare Enterprise (IHE) workflow profiles. In addition, the integration method is Health Insurance Portability and Accountability Act (HIPAA) compliant. The paper presents (1) the clinical value and advantages of integrating CAD results in a PACS environment, (2) DICOM Structured Reporting formats and some important IHE workflow profiles utilized in the system integration, (3) the methodology using the CAD-PACS integration toolkit, and (4) clinical examples with step-by-step workflows of this integration. (orig.)

Role of pacs in an integrated communication system

International Nuclear Information System (INIS)

Thompson, B.G.; Creasy, J.L.; Johnston, R.E.; Parrish, D.; Scatliff, J.H.

1986-01-01

An integrated computer-based communications system uses multiple computers for the high speed transmission, storage, enhancement and display for medical information. Interconnected by a network such as coaxial and fiberoptic cables or microwave stations, the system would provide integrated communications throughout a satellite medical environment. As the availability of proven PACS components becomes a commercial reality, migratory expansion of PACS within the radiology clinical, educational and research areas will be possible. When the PACS is integrated with hospital, radiology and medical school information systems it provides the image component of a total medical information system. Current PACS efforts are on a research basis including the development of prototype systems. This paper provides an overview of implementation strategies. Issues to be discussed include PACS research objectives, typical implementation methods, and a review of interactions between PACS and radiology information systems (RIS) and hospital information systems

Tracking PACS usage with open source tools.

Science.gov (United States)

French, Todd L; Langer, Steve G

2011-08-01

A typical choice faced by Picture Archiving and Communication System (PACS) administrators is deciding how many PACS workstations are needed and where they should be sited. Oftentimes, the social consequences of having too few are severe enough to encourage oversupply and underutilization. This is costly, at best in terms of hardware and electricity, and at worst (depending on the PACS licensing and support model) in capital costs and maintenance fees. The PACS administrator needs tools to asses accurately the use to which her fleet is being subjected, and thus make informed choices before buying more workstations. Lacking a vended solution for this challenge, we developed our own.

THE ROLE OF TURBULENT MAGNETIC RECONNECTION IN THE FORMATION OF ROTATIONALLY SUPPORTED PROTOSTELLAR DISKS

Energy Technology Data Exchange (ETDEWEB)

Santos-Lima, R.; De Gouveia Dal Pino, E. M. [Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo, R. do Matao, 1226, Sao Paulo, SP 05508-090 (Brazil); Lazarian, A. [Department of Astronomy, University of Wisconsin, Madison, WI 53706 (United States)

2012-03-01

The formation of protostellar disks out of molecular cloud cores is still not fully understood. Under ideal MHD conditions, the removal of angular momentum from the disk progenitor by the typically embedded magnetic field may prevent the formation of a rotationally supported disk during the main protostellar accretion phase of low-mass stars. This has been known as the magnetic braking problem and the most investigated mechanism to alleviate this problem and help remove the excess of magnetic flux during the star formation process, the so-called ambipolar diffusion (AD), has been shown to be not sufficient to weaken the magnetic braking at least at this stage of the disk formation. In this work, motivated by recent progress in the understanding of magnetic reconnection in turbulent environments, we appeal to the diffusion of magnetic field mediated by magnetic reconnection as an alternative mechanism for removing magnetic flux. We investigate numerically this mechanism during the later phases of the protostellar disk formation and show its high efficiency. By means of fully three-dimensional MHD simulations, we show that the diffusivity arising from turbulent magnetic reconnection is able to transport magnetic flux to the outskirts of the disk progenitor at timescales compatible with the collapse, allowing the formation of a rotationally supported disk around the protostar of dimensions {approx}100 AU, with a nearly Keplerian profile in the early accretion phase. Since MHD turbulence is expected to be present in protostellar disks, this is a natural mechanism for removing magnetic flux excess and allowing the formation of these disks. This mechanism dismisses the necessity of postulating a hypothetical increase of the ohmic resistivity as discussed in the literature. Together with our earlier work which showed that magnetic flux removal from molecular cloud cores is very efficient, this work calls for reconsidering the relative role of AD in the processes of star

'Land-marks of the universe': John Herschel against the background of positional astronomy.

Science.gov (United States)

Case, Stephen

2015-01-01

John Herschel (1792-1871) was the leading British natural philosopher of the nineteenth century, widely known and regarded for his work in philosophy, optics and chemistry as well as his important research and popular publications on astronomy. To date, however, there exists no extended treatment of his astronomical career. This paper, part of a larger study exploring Herschel's contributions to astronomy, examines his work in the context of positional astronomy, the dominant form of astronomical practice throughout his lifetime. Herschel, who did not himself practice positional astronomy and who was known for his non-meridional observations of specific stellar objects, was nonetheless a strong advocate for positional astronomy-but for very different reasons than the terrestrial applications to which it was most often put. For Herschel, the star catalogues of positional astronomy were the necessary observational foundation upon which information about the stars as physical objects could be constructed. Positional astronomy practiced in the great national observatories was not about navigation or timekeeping; it was a way to standardize stellar observations and make them useful data for constructing theories of the stars themselves. For Herschel, the seeds of the new astronomy emerged from the practices of the old.

PACS: implementation in the U.S. Department of Defense

Science.gov (United States)

Chacko, Anna K.; Wider, Ronald; Romlein, John R.; Cawthon, Michael A.; Richardson, Ronald R., Jr.; Lollar, H. William; Cook, Jay F.; Timboe, Harold L.; Johnson, Thomas G.; Fellows, Douglas W.

2000-05-01

The Department of Defense has been a leader in Radiology re- engineering for the past decade. Efforts have included the development of two landmark PACS specifications (MDIS and DIN- PACS), respective vendor selection and implementation programs. A Tri-Service (Army, Navy and Air Force) Radiology re-engineering program was initiated which identified transitioning to digital imaging, PACS and teleradiology as key enabling technologies in a changing business scenario. Subsequently, the systematic adjustment of procurement process for radiological imaging equipment included a focus on specifying PACS-capable-digital imaging modalities and mini- PACS as stepping stones to make the hospitals and health clinics PACS-ready. The success of the PACS and teleradiology program in the DOD is evidenced by the near filmless operation of most Army and Air Force Medical Centers, several community hospitals and several operational teleradiology constellations. Additionally, the MDIS PACSystem has become the commercial PACS product for General Electric Medical Systems. The DOD continues to forge ahead in the PACS arena by implementing advanced configurations and operational concepts such as the VRE (Virtual Radiology Environment), the negotiation of Regional Archiving and Regional PACS Maintenance Programs. Newer regulations (HIPAA, the FDA approval of digital mammography) have been promulgated impacting the culture and conduct of our business. Incorporating their requirements at the very outset will enable us to streamline the delivery of radiology. The DOD community has embraced the information age at multiple levels. The Healthcare portion of this community with these initiatives is integrating itself into DOD's future. The future holds great possibilities, promises and challenges for the DOD PACS programs.

Second-generation PACS

International Nuclear Information System (INIS)

Mattheus, R.; Osteaux, M.; Spruiyt, D.

1989-01-01

Purpose: In recent years, a gradual shift toward digital techniques has occurred in the field of medical imaging. The authors discuss how, with their approach, digital image management can be used in daily clinical routine. Instead of a centralized approach, we have taken a decentralized, multivendor, phase-expandable approach. The IMAC (image management and communication) architecture is a reflection of the organization of the imaging department. A section defined for each group of examinations (CT, MR imaging, DSA, emergency), has its own (dedicated) PACS environment, connected to the total PACS. Network management for controlling the image flow is based on patient appointments, scheduling of rooms, and work

PACS in the nuclear medicine service

International Nuclear Information System (INIS)

Bitter, F.; Hellwig, D.; Weller, R.; Almasi, L.; Adam, W.E.

1988-01-01

A Picture Archiving and Communication System (PACS) is to be understood as a central system in a hospital spanning all services, interconnecting all imaging stations and allowing digital picture archivation. All data of a patient are prepared for direct access. A PAC system is made up of the following components: imaging equipment and data systems, viewing stations (image display), picture communication, storage, archive, connection to hospital information system. The authors explain the requirements to be met by a PACS, its set-up and mode of function, and they system the use. (orig./MG) [de

Multilayer Formation and Evaporation of Deuterated Ices in Prestellar and Protostellar Cores

Science.gov (United States)

Taquet, Vianney; Charnley, Steven B.; Sipilä, Olli

2014-08-01

Extremely large deuteration of several molecules has been observed toward prestellar cores and low-mass protostars for a decade. New observations performed toward low-mass protostars suggest that water presents a lower deuteration in the warm inner gas than in the cold external envelope. We coupled a gas-grain astrochemical model with a one-dimensional model of a collapsing core to properly follow the formation and the deuteration of interstellar ices as well as their subsequent evaporation in the low-mass protostellar envelopes with the aim of interpreting the spatial and temporal evolutions of their deuteration. The astrochemical model follows the formation and the evaporation of ices with a multilayer approach and also includes a state-of-the-art deuterated chemical network by taking the spin states of H2 and light ions into account. Because of their slow formation, interstellar ices are chemically heterogeneous and show an increase of their deuterium fractionation toward the surface. The differentiation of the deuteration in ices induces an evolution of the deuteration within protostellar envelopes. The warm inner region is poorly deuterated because it includes the whole molecular content of ices, while the deuteration predicted in the cold external envelope scales with the highly deuterated surface of ices. We are able to reproduce the observed evolution of water deuteration within protostellar envelopes, but we are still unable to predict the super-high deuteration observed for formaldehyde and methanol. Finally, the extension of this study to the deuteration of complex organics, important for the prebiotic chemistry, shows good agreement with the observations, suggesting that we can use the deuteration to retrace their mechanisms and their moments of formation.

Multilayer formation and evaporation of deuterated ices in prestellar and protostellar cores

International Nuclear Information System (INIS)

Taquet, Vianney; Charnley, Steven B.; Sipilä, Olli

2014-01-01

Extremely large deuteration of several molecules has been observed toward prestellar cores and low-mass protostars for a decade. New observations performed toward low-mass protostars suggest that water presents a lower deuteration in the warm inner gas than in the cold external envelope. We coupled a gas-grain astrochemical model with a one-dimensional model of a collapsing core to properly follow the formation and the deuteration of interstellar ices as well as their subsequent evaporation in the low-mass protostellar envelopes with the aim of interpreting the spatial and temporal evolutions of their deuteration. The astrochemical model follows the formation and the evaporation of ices with a multilayer approach and also includes a state-of-the-art deuterated chemical network by taking the spin states of H 2 and light ions into account. Because of their slow formation, interstellar ices are chemically heterogeneous and show an increase of their deuterium fractionation toward the surface. The differentiation of the deuteration in ices induces an evolution of the deuteration within protostellar envelopes. The warm inner region is poorly deuterated because it includes the whole molecular content of ices, while the deuteration predicted in the cold external envelope scales with the highly deuterated surface of ices. We are able to reproduce the observed evolution of water deuteration within protostellar envelopes, but we are still unable to predict the super-high deuteration observed for formaldehyde and methanol. Finally, the extension of this study to the deuteration of complex organics, important for the prebiotic chemistry, shows good agreement with the observations, suggesting that we can use the deuteration to retrace their mechanisms and their moments of formation.

Multilayer formation and evaporation of deuterated ices in prestellar and protostellar cores

Energy Technology Data Exchange (ETDEWEB)

Taquet, Vianney; Charnley, Steven B. [Astrochemistry Laboratory and The Goddard Center for Astrobiology, Mailstop 691, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20770 (United States); Sipilä, Olli [Department of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki (Finland)

2014-08-10

Extremely large deuteration of several molecules has been observed toward prestellar cores and low-mass protostars for a decade. New observations performed toward low-mass protostars suggest that water presents a lower deuteration in the warm inner gas than in the cold external envelope. We coupled a gas-grain astrochemical model with a one-dimensional model of a collapsing core to properly follow the formation and the deuteration of interstellar ices as well as their subsequent evaporation in the low-mass protostellar envelopes with the aim of interpreting the spatial and temporal evolutions of their deuteration. The astrochemical model follows the formation and the evaporation of ices with a multilayer approach and also includes a state-of-the-art deuterated chemical network by taking the spin states of H{sub 2} and light ions into account. Because of their slow formation, interstellar ices are chemically heterogeneous and show an increase of their deuterium fractionation toward the surface. The differentiation of the deuteration in ices induces an evolution of the deuteration within protostellar envelopes. The warm inner region is poorly deuterated because it includes the whole molecular content of ices, while the deuteration predicted in the cold external envelope scales with the highly deuterated surface of ices. We are able to reproduce the observed evolution of water deuteration within protostellar envelopes, but we are still unable to predict the super-high deuteration observed for formaldehyde and methanol. Finally, the extension of this study to the deuteration of complex organics, important for the prebiotic chemistry, shows good agreement with the observations, suggesting that we can use the deuteration to retrace their mechanisms and their moments of formation.

On protostellar evolution

International Nuclear Information System (INIS)

Westbrook, C.K.; Tarter, C.B.

1975-01-01

An investigation of the evolution of spherically symmetric protostars with initial masses in the range 0.1less than or equal toM/M/sub sun/less than or equal to50 has been carried out. In order to perform the calculations, a numerical technique has been developed in which rapid dynamical motions in one region of the star and quasi-static evolution in another region can be simultaneously computed. The general evolutionary features are similar to those found by other workers: an initial free-fall collapse is followed by the creation of a core in hydrostatic equilibrium, and the core's subsequent accretion of the surrounding envelope. However, our final hydrostatic-equilibrium configurations have radii large compared with those of the protostellar models of Larson (but in reasonable agreement with those of conventional pre-main-sequence models). For low-mass protostars (Mless than or equal toM/sub sun/) the luminosity remains relatively small until late evolutionary times and the evolution is very sensitive to the treatment of convective energy transport. For large-mass protostars (Mgreater than or equal to3M/sub sun/) a convective phase never exists, and a fraction (increasing with mass) of the initial mass is ejected by the combined effects of heating and radiation pressure in the envelope

Reengineering the picture archiving and communication system (PACS) process for digital imaging networks PACS

OpenAIRE

Horton, Maria C.; Lewis, Thomas E.; Kinsey, Thomas V.

1999-01-01

Prior to June 1997, military picture archiving and communications systems (PACS) were planned, procured, and installed with key decisions on the system, equipment, and even funding sources made through a research and development office called Medical Diagnostic Imaging Systems (MDIS). Beginning in June 1997, the Joint Imaging Technology Project Office (JITPO) initiated a collaborative and consultative process for planning and implementing PACS into military treatment facilities through a new ...

Can PACS make a radiology department more competitive?

International Nuclear Information System (INIS)

Strickland, Nicola H.

1999-01-01

One of the motives for putting in a picture archiving and communication system (PACS) is to improve efficiency and hence enhance the competitive strength of the radiology department. Many would argue that it is now negligent to consider installing an old fashioned conventional radiology department rather than a PACS. In considering the issue it is important to be clear about the nature of the competition facing radiologists. This varies depending on the country and upon whether the institution is public or private. PACS can potentially help to overcome this competition in two ways: by providing real-time radiology, and by enabling teleradiology. Success in these areas requires state-of-the-art implementations of PACS, particularly clinically relevant PACS software, and adequate staffing levels

THE MASSIVE PROTOSTELLAR CLUSTER NGC 6334I AT 220 au RESOLUTION: DISCOVERY OF FURTHER MULTIPLICITY, DIVERSITY, AND A HOT MULTI-CORE

Energy Technology Data Exchange (ETDEWEB)

Brogan, C. L.; Hunter, T. R.; Indebetouw, R. [NRAO, 520 Edgemont Rd, Charlottesville, VA 22903 (United States); Cyganowski, C. J. [SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS (United Kingdom); Chandler, C. J. [NRAO, P.O. Box 0, Socorro, NM 87801 (United States); Friesen, R., E-mail: cbrogan@nrao.edu [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, Toronto, Ontario, M5S 3H4 (Canada)

2016-12-01

We present Very Large Array and Atacama Large Millimeter/submillimeter Array imaging of the deeply embedded protostellar cluster NGC 6334I from 5 cm to 1.3 mm at angular resolutions as fine as 0.″17 (220 au). The dominant hot core MM1 is resolved into seven components at 1.3 mm, clustered within a radius of 1000 au. Four of the components have brightness temperatures >200 K, radii ∼300 au, minimum luminosities ∼10{sup 4} L {sub ⊙}, and must be centrally heated. We term this new phenomenon a “hot multi-core.” Two of these objects also exhibit compact free–free emission at longer wavelengths, consistent with a hypercompact H ii region (MM1B) and a jet (MM1D). The spatial kinematics of the water maser emission centered on MM1D are consistent with it being the origin of the high-velocity bipolar molecular outflow seen in CO. The close proximity of MM1B and MM1D (440 au) suggests a proto-binary or a transient bound system. Several components of MM1 exhibit steep millimeter spectral energy distributions indicative of either unusual dust spectral properties or time variability. In addition to resolving MM1 and the other hot core (MM2) into multiple components, we detect five new millimeter and two new centimeter sources. Water masers are detected for the first time toward MM4A, confirming its membership in the protocluster. With a 1.3 mm brightness temperature of 97 K coupled with a lack of thermal molecular line emission, MM4A appears to be a highly optically thick 240  L {sub ⊙} dust core, possibly tracing a transient stage of massive protostellar evolution. The nature of the strongest water maser source CM2 remains unclear due to its combination of non-thermal radio continuum and lack of dust emission.

SPITZER IMAGING OF STRONGLY LENSED HERSCHEL-SELECTED DUSTY STAR-FORMING GALAXIES

Energy Technology Data Exchange (ETDEWEB)

Ma, Brian; Cooray, Asantha; Calanog, J. A.; Nayyeri, H.; Timmons, N.; Casey, C. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Baes, M. [Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281 S9, B-9000 Gent (Belgium); Chapman, S. [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia, B3H 4R2 (Canada); Dannerbauer, H. [Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu-CNRS-Université Paris Diderot, CE-Saclay, pt courrier 131, F-91191 Gif-sur-Yvette (France); Da Cunha, E. [Center for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn VIC 3122 (Australia); De Zotti, G. [INAF-Osservatorio Astronomico di Padova, Vicolo Osservatorio 5, I-35122 Padova (Italy); Dunne, L.; Michałowski, M. J.; Oteo, I. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ (United Kingdom); Farrah, D. [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Fu, Hai [Department of Physics and Astronomy, University of Iowa, Van Allen Hall, Iowa City, IA 52242 (United States); Gonzalez-Nuevo, J. [Departamento de Fisica, Universidad de Oviedo C/ Calvo Sotelo, s/n, E-33007 Oviedo (Spain); Magdis, G. [Department of Astrophysics, Denys Wilkinson Building, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Riechers, D. A. [Department of Astronomy, Cornell University, 220 Space Sciences Building, Ithaca, NY 14853 (United States); Scott, D. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); and others

2015-11-20

We present the rest-frame optical spectral energy distribution (SED) and stellar masses of six Herschel-selected gravitationally lensed dusty, star-forming galaxies (DSFGs) at 1 < z < 3. These galaxies were first identified with Herschel/SPIRE imaging data from the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) and the Herschel Multi-tiered Extragalactic Survey (HerMES). The targets were observed with Spitzer/IRAC at 3.6 and 4.5 μm. Due to the spatial resolution of the IRAC observations at the level of 2″, the lensing features of a background DSFG in the near-infrared are blended with the flux from the foreground lensing galaxy in the IRAC imaging data. We make use of higher resolution Hubble/WFC3 or Keck/NIRC2 Adaptive Optics imaging data to fit light profiles of the foreground lensing galaxy (or galaxies) as a way to model the foreground components, in order to successfully disentangle the foreground lens and background source flux densities in the IRAC images. The flux density measurements at 3.6 and 4.5 μm, once combined with Hubble/WFC3 and Keck/NIRC2 data, provide important constraints on the rest-frame optical SED of the Herschel-selected lensed DSFGs. We model the combined UV- to millimeter-wavelength SEDs to establish the stellar mass, dust mass, star formation rate, visual extinction, and other parameters for each of these Herschel-selected DSFGs. These systems have inferred stellar masses in the range 8 × 10{sup 10}–4 × 10{sup 11} M{sub ⊙} and star formation rates of around 100 M{sub ⊙} yr{sup −1}. This puts these lensed submillimeter systems well above the SFR-M* relation observed for normal star-forming galaxies at similar redshifts. The high values of SFR inferred for these systems are consistent with a major merger-driven scenario for star formation.

The new galaxy evolution paradigm revealed by the Herschel surveys

Science.gov (United States)

Eales, Stephen; Smith, Dan; Bourne, Nathan; Loveday, Jon; Rowlands, Kate; van der Werf, Paul; Driver, Simon; Dunne, Loretta; Dye, Simon; Furlanetto, Cristina; Ivison, R. J.; Maddox, Steve; Robotham, Aaron; Smith, Matthew W. L.; Taylor, Edward N.; Valiante, Elisabetta; Wright, Angus; Cigan, Philip; De Zotti, Gianfranco; Jarvis, Matt J.; Marchetti, Lucia; Michałowski, Michał J.; Phillipps, Steven; Viaene, Sebastien; Vlahakis, Catherine

2018-01-01

The Herschel Space Observatory has revealed a very different galaxyscape from that shown by optical surveys which presents a challenge for galaxy-evolution models. The Herschel surveys reveal (1) that there was rapid galaxy evolution in the very recent past and (2) that galaxies lie on a single Galaxy Sequence (GS) rather than a star-forming 'main sequence' and a separate region of 'passive' or 'red-and-dead' galaxies. The form of the GS is now clearer because far-infrared surveys such as the Herschel ATLAS pick up a population of optically red star-forming galaxies that would have been classified as passive using most optical criteria. The space-density of this population is at least as high as the traditional star-forming population. By stacking spectra of H-ATLAS galaxies over the redshift range 0.001 high stellar masses, high star-formation rates but, even several billion years in the past, old stellar populations - they are thus likely to be relatively recent ancestors of early-type galaxies in the Universe today. The form of the GS is inconsistent with rapid quenching models and neither the analytic bathtub model nor the hydrodynamical EAGLE simulation can reproduce the rapid cosmic evolution. We propose a new gentler model of galaxy evolution that can explain the new Herschel results and other key properties of the galaxy population.

Continued monitoring of aeolian activity within Herschel Crater, Mars

Science.gov (United States)

Cardinale, Marco; Pozzobon, Riccardo; Michaels, Timothy; Bourke, Mary C.; Okubo, Chris H.; Chiara Tangari, Anna; Marinangeli, Lucia

2017-04-01

In this work, we study a dark dune field on the western side of Herschel crater, a 300 km diameter impact basin located near the Martian equator (14.4°S, 130°E), where the ripple and dune motion reflects the actual atmospheric wind conditions. We develop an integrated analysis using (1) automated ripple mapping that yields ripple orientations and evaluates the spatial variation of actual atmospheric wind conditions within the dunes, (2) an optical cross-correlation that allows us to quantify an average ripple migration rate of 0.42 m per Mars year, and (3) mesoscale climate modeling with which we compare the observed aeolian changes with modeled wind stresses and directions. Our observations are consistent with previous work [1] [2] that detected aeolian activity in the western part of the crater. It also demonstrates that not only are the westerly Herschel dunes movable, but that predominant winds from the north are able to keep the ripples and dunes active within most (if not all) of Herschel crater in the current atmospheric conditions. References: [1] Cardinale, M., Silvestro, S., Vaz, D.A., Michaels, T., Bourke, M.C., Komatsu, G., Marinangeli, L., 2016. Present-day aeolian activity in Herschel Crater, Mars. Icarus 265, 139-148. doi:10.1016/j.icarus.2015.10.022. [2] Runyon, K.D., Bridges, N.T., Ayoub, F., Newman, C.E. and Quade, J.J., 2017. An integrated model for dune morphology and sand fluxes on Mars. Earth and Planetary Science Letters, 457, pp.204-212.

IHE profiles applied to regional PACS

International Nuclear Information System (INIS)

Fernandez-Bayo, Josep

2011-01-01

PACS has been widely adopted as an image storage solution that perfectly fits the radiology department workflow and that can be easily extended to other hospital departments. Integrations with other hospital systems, like the Radiology Information System, the Hospital Information System and the Electronic Patient Record are fully achieved but still challenging aims. PACS also creates the perfect environment for teleradiology and teleworking setups. One step further is the regional PACS concept where different hospitals or health care enterprises share the images in an integrated Electronic Patient Record. Among the different solutions available to share images between different hospitals IHE (Integrating the Healthcare Enterprise) organization presents the Cross Enterprise Document Sharing profile (XDS) which allows sharing images from different hospitals even if they have different PACS vendors. Adopting XDS has multiple advantages, images do not need to be duplicated in a central archive to be shared among the different healthcare enterprises, they only need to be indexed and published in a central document registry. In the XDS profile IHE defines the mechanisms to publish and index the images in the central document registry. It also defines the mechanisms that each hospital will use to retrieve those images regardless on the Hospital PACS they are stored.

Urological diagnosis using clinical PACS

Science.gov (United States)

Mills, Stephen F.; Spetz, Kevin S.; Dwyer, Samuel J., III

1995-05-01

Urological diagnosis using fluoroscopy images has traditionally been performed using radiographic films. Images are generally acquired in conjunction with the application of a contrast agent, processed to create analog films, and inspected to ensure satisfactory image quality prior to being provided to a radiologist for reading. In the case of errors the entire process must be repeated. In addition, the radiologist must then often go to a particular reading room, possibly in a remote part of the healthcare facility, to read the images. The integration of digital fluoroscopy modalities with clinical PACS has the potential to significantly improve the urological diagnosis process by providing high-speed access to images at a variety of locations within a healthcare facility without costly film processing. The PACS additionally provides a cost-effective and reliable means of long-term storage and allows several medical users to simultaneously view the same images at different locations. The installation of a digital data interface between the existing clinically operational PACS at the University of Virginia Health Sciences Center and a digital urology fluoroscope is described. Preliminary user interviews that have been conducted to determine the clinical effectiveness of PACS workstations for urological diagnosis are discussed. The specific suitability of the workstation medium is discussed, as are overall advantages and disadvantages of the hardcopy and softcopy media in terms of efficiency, timeliness and cost. Throughput metrics and some specific parameters of gray-scale viewing stations and the expected system impacts resulting from the integration of a urology fluoroscope with PACS are also discussed.

PACS strategy for imaging centers.

Science.gov (United States)

Bedel, Victoria; Zdanowicz, Mark

2004-01-01

Picture archiving and communications systems (PACS) have been available in imaging centers for many years, but they often were less functional, were not well integrated into patient information systems, and lacked the network backbone to implement a system. As modalities are replaced and technology improves, the ability and time for an imaging center to acquire, integrate, and utilize PACS has arrived. However, each imaging center must determine why it should invest in PACS. A business plan is the fundamental need. Each imaging center must understand its target market, growth rate, and staffing plans. Additional considerations lie in current and future modality availability, the need for offsite delivery of images and reports, and the potential need for remote transmission of images. These issues must be identified and prioritized. A multidisciplinary team is essential. The most successful PACS implementation begins with complete involvement from all levels. The team should be comprised of people with complementary skills who are committed to a common purpose, set of performance goals, and approach for which they hold themselves mutually accountable. The team must jointly decide on the project's objectives. These objectives fall under 4 categories: clinical, service, financial, and performance. PACS must be considered a tool to help accomplish each objective. The imaging center must determine its top priorities, then translate them into a technology "wish list." The center can then list those pieces of technology that are most important and prioritize them. There are even more considerations for connecting multiple imaging centers. The team must create a comprehensive request for proposal (RFP) and determine the vendors that will receive the document. Once the RFP responses have been received and the vendor has been selected, an effective training plan must be executed. Training plans should be competency-based, ensuring comfort and competency among all staff. Upon

PACS influence the radiographer's work

International Nuclear Information System (INIS)

Fridell, Kent; Aspelin, Peter; Edgren, Lars; Lindskoeld, Lars; Lundberg, Nina

2009-01-01

Radiological departments are changing rapidly due to the implementation of digital images and PACS (Picture Archiving and Communication Systems). The introduction of new technology seems to dissolve boundaries between the professions in the work environment where the technology is introduced. This process tends to change the organization and its routines. The aim of this qualitative study is to explore changes in radiographers' work with regard to skills, work practice and technology. The study used open-ended interviews to explore the radiographers' perceptions of such changes, and to identify problems and solutions pertaining to work practice. Inspiration is taken from grounded theory to explain the changes in work that were found. Respondents were selected from a total of 133 potential participants as a theoretical or purposive sample. The changing trends within the professional role indicated that radiographers, as image producers, shifted their focus from the ability to set the optimal exposure parameters in order to obtain the optimal image for diagnosis to become expert in exposure parameters, projection techniques and diagnostic practice, having multifaceted skills, as being the jack of all trades. When implementing PACS there was an obvious change in image production. At the start there were visions of new routines, and therefore the radiographers became early adopters to the new technology; in practice the organization was stacked in old routines, as the routines were inflexible and PACS work was pushed into old work routines. Although inflexible, this does not mean that they cannot change, and obviously in 2006 new routines had been implemented making it possible for the radiographers in finding new ways for collaborating with colleagues. The new technology immediately created a vision of improved service to the clinicians. In order to optimize the service the radiographers developed an insight into the need for a more comprehensive change in work using

Massive Outflows Associated with ATLASGAL Clumps

Science.gov (United States)

Yang, A. Y.; Thompson, M. A.; Urquhart, J. S.; Tian, W. W.

2018-03-01

We have undertaken the largest survey for outflows within the Galactic plane using simultaneously observed {}13{CO} and {{{C}}}18{{O}} data. Out of a total of 919 ATLASGAL clumps, 325 have data suitable to identify outflows, and 225 (69% ± 3%) show high-velocity outflows. The clumps with detected outflows show significantly higher clump masses ({M}clump}), bolometric luminosities ({L}bol}), luminosity-to-mass ratios ({L}bol}/{M}clump}), and peak H2 column densities ({N}{{{H}}2}) compared to those without outflows. Outflow activity has been detected within the youngest quiescent clump (i.e., 70 μ {{m}} weak) in this sample, and we find that the outflow detection rate increases with {M}clump}, {L}bol}, {L}bol}/{M}clump}, and {N}{{{H}}2}, approaching 90% in some cases (UC H II regions = 93% ± 3%; masers = 86% ± 4%; HC H II regions = 100%). This high detection rate suggests that outflows are ubiquitous phenomena of massive star formation (MSF). The mean outflow mass entrainment rate implies a mean accretion rate of ∼ {10}-4 {M}ȯ {yr}}-1, in full agreement with the accretion rate predicted by theoretical models of MSF. Outflow properties are tightly correlated with {M}clump}, {L}bol}, and {L}bol}/{M}clump} and show the strongest relation with the bolometric clump luminosity. This suggests that outflows might be driven by the most massive and luminous source within the clump. The correlations are similar for both low-mass and high-mass outflows over 7 orders of magnitude, indicating that they may share a similar outflow mechanism. Outflow energy is comparable to the turbulent energy within the clump; however, we find no evidence that outflows increase the level of clump turbulence as the clumps evolve. This implies that the origin of turbulence within clumps is fixed before the onset of star formation.

The circumstellar environment of evolved stars as traced by molecules and dust. The diagnostic power of Herschel

Science.gov (United States)

Lombaert, Robin

2013-12-01

Low-to-intermediate mass stars end their life on the asymptotic giant branch (AGB), an evolutionary phase in which the star sheds most of its mantle into the circumstellar environment through a stellar wind. This stellar wind expands at relatively low velocities and enriches the interstellar medium with elements newly made in the stellar interior. The physical processes controlling the gas and dust chemistry in the outflow, as well as the driving mechanism of the wind itself, are poorly understood and constitute the broader context of this thesis work. In a first chapter, we consider the thermodynamics of the high-density wind of the oxygen-rich star oh, using observations obtained with the PACS instrument onboard the Herschel Space Telescope. Being one of the most abundant molecules, water vapor can be dominant in the energy balance of the inner wind of these types of stars, but to date, its cooling contribution is poorly understood. We aim to improve the constraints on water properties by careful combination of both dust and gas radiative-transfer models. This unified treatment is needed due to the high sensitivity of water excitation to dust properties. A combination of three types of diagnostics reveals a positive radial gradient of the dust-to-gas ratio in oh. The second chapter deals with the dust chemistry of carbon-rich winds. The 30-mic dust emission feature is commonly identified as due to magnesium sulfide (MgS). However, the lack of short-wavelength measurements of the optical properties of this dust species prohibits the determination of the temperature profile of MgS, and hence its feature strength and shape, questioning whether this species is responsible for the 30-mic feature. By considering the very optically thick wind of the extreme carbon star LL Peg, this problem can be circumvented because in this case the short-wavelength optical properties are not important for the radial temperature distribution. We attribute the 30-mic feature to MgS, but

Making PACS the present, not the future.

Science.gov (United States)

Hunt, D

1998-01-01

Why haven't you moved forward with PACS? Have you just procrastinated or does your facility have legitimate reasons? Some say the technology is too confusing or too new, while others say the cost of PACS is too high. Many facilities say they haven't found a satisfactory way to deal with the conflicting opinions of their radiologists, IS department, administration, referring physicians and staff. Take time to compare the technology you do understand with something familiar such as your own PC or perhaps the current networks inside your facility. You'll soon begin to see that PACS is not a new technology, but rather a new methodology. To handle the perceived high cost of PACS, remember that every facility has different needs. Look at your work flow and then the many byproducts of PACS, such as marketing. If you are the first in your area to implement this new technology, you'll gain a marketing advantage in competing for referring physicians and managed care referral business. Follow the process you use to purchase other products, such as CT or MRI, as you investigate the vendors. Finally, make a plan! Determine departmental goals and gather information from vendors. Create a timeline, a financial plan and your marketing strategy. Together, these steps will help move PACS into the present for you.

Design and Implementation of PACS at Georgetown University Hospital

Science.gov (United States)

Mun, S. K.; Benson, H.. R.; Choyke, P.; Fahey, F. H.; Wang, P. C.; Zeman, R. K...; Elliott, L. P.

1985-09-01

During the preparation and planning phase of the PACS project at Georgetown University Hospital it was realized that PACS requires truly the state of the art technology in data communication, image processing and man machine interfacing. It was also realized that un-like many other technology intensive devices used in radiology, PACS cannot be seen as an independent system that will provide well defined services. PACS will be the backbone of the department operation in clinical, educational and managerial functions. It will indeed be the nerve center of the radiologic services affecting every aspect of the department. PACS will have to be designed to perform in a cost-effective manner to widely varying needs within the radiology departments. The integration of ever changing complex technology that will impact every aspect of a radiology service is not a trivial matter. This transition period going from current manual film based PACS to Digital PACS can be long, expansive and disruptive unless careful planning preceeds the implementation. PACS is still an emerging technology at its infancy. Performance monitoring and evaluation of diversified functions have to be also established so that improvement to the system can be efficiently implemented. Thus the evaluation criteria should be also established as early as possible.

Cloning and expression profiling of the PacSnRK2 and PacPP2C gene families during fruit development, ABA treatment, and dehydration stress in sweet cherry.

Science.gov (United States)

Shen, Xinjie; Guo, Xiao; Zhao, Di; Zhang, Qiang; Jiang, Yuzhuang; Wang, Yantao; Peng, Xiang; Wei, Yan; Zhai, Zefeng; Zhao, Wei; Li, Tianhong

2017-10-01

Plant SNF1-related protein kinase 2 (SnRK2) and protein phosphatase 2C (PP2C) family members are core components of the ABA signal transduction pathway. SnRK2 and PP2C proteins have been suggested to play crucial roles in fruit ripening and improving plant tolerance to drought stress, but supporting genetic information has been lacking in sweet cherry (Prunus avium L.). Here, we cloned six full-length SnRK2 genes and three full-length PP2C genes from sweet cherry cv. Hong Deng. Quantitative PCR analysis revealed that PacSnRK2.2, PacSnRK2.3, PacSnRK2.6, and PacPP2C1-3 were negatively regulated in fruits in response to exogenous ABA treatment, PacSnRK2.4 and PacSnRK2.5 were upregulated, and PacSnRK2.1 expression was not affected. The ABA treatment also significantly promoted the accumulation of anthocyanins in sweet cherry fruit. The expression of all PacSnRK2 and PacPP2C genes was induced by dehydration stress, which also promoted the accumulation of drought stress signaling molecules in the sweet cherry fruits, including ABA, soluble sugars, and anthocyanin. Furthermore, a yeast two-hybrid analysis demonstrated that PacPP2C1 interacts with all six PacSnRK2s, while PacPP2C3 does not interact with PacSnRK2.5. PacPP2C2 does not interact with PacSnRK2.1 or PacSnRK2.4. These results indicate that PacSnRK2s and PacPP2Cs may play a variety of roles in the sweet cherry ABA signaling pathway and the fruit response to drought stress. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

HERSCHEL SPECTROSCOPIC OBSERVATIONS OF LITTLE THINGS DWARF GALAXIES

International Nuclear Information System (INIS)

Cigan, Phil; Young, Lisa; Cormier, Diane; Lebouteiller, Vianney; Madden, Suzanne; Hunter, Deidre; Brinks, Elias; Elmegreen, Bruce; Schruba, Andreas; Heesen, Volker

2016-01-01

We present far-infrared (FIR) spectral line observations of five galaxies from the Little Things sample: DDO 69, DDO 70, DDO 75, DDO 155, and WLM. While most studies of dwarfs focus on bright systems or starbursts due to observational constraints, our data extend the observed parameter space into the regime of low surface brightness dwarf galaxies with low metallicities and moderate star formation rates. Our targets were observed with Herschel at the [C ii] 158 μm, [O i] 63 μm, [O iii] 88 μm, and [N ii] 122 μm emission lines using the PACS Spectrometer. These high-resolution maps allow us for the first time to study the FIR properties of these systems on the scales of larger star-forming complexes. The spatial resolution in our maps, in combination with star formation tracers, allows us to identify separate photodissociation regions (PDRs) in some of the regions we observed. Our systems have widespread [C ii] emission that is bright relative to continuum, averaging near 0.5% of the total infrared (TIR) budget—higher than in solar-metallicity galaxies of other types. [N ii] is weak, suggesting that the [C ii] emission in our galaxies comes mostly from PDRs instead of the diffuse ionized interstellar medium (ISM). These systems exhibit efficient cooling at low dust temperatures, as shown by ([O i]+[C ii])/TIR in relation to 60 μm/100 μm, and low [O i]/[C ii] ratios which indicate that [C ii] is the dominant coolant of the ISM. We observe [O iii]/[C ii] ratios in our galaxies that are lower than those published for other dwarfs, but similar to levels noted in spirals

HERSCHEL SPECTROSCOPIC OBSERVATIONS OF LITTLE THINGS DWARF GALAXIES

Energy Technology Data Exchange (ETDEWEB)

Cigan, Phil; Young, Lisa [Physics Department, New Mexico Institute of Mining and Technology, Socorro, NM 87801 (United States); Cormier, Diane [Institut für Theoretische Astrophysik, Zentrum für Astronomie der Universität Heidelberg, Albert-Ueberle Str. 2, D-69120 Heidelberg (Germany); Lebouteiller, Vianney; Madden, Suzanne [Laboratoire AIM, CEA/DSM—CNRS—Université Paris Diderot, Irfu/Service d’Astrophysique, CEA Saclay, F-91191 Gif-sur-Yvette (France); Hunter, Deidre [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Brinks, Elias [Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield, AL10 9AB (United Kingdom); Elmegreen, Bruce [IBM T.J. Watson Research Center, 1101 Kitchawan Road, Yorktown Hts., NY 10598 (United States); Schruba, Andreas [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany); Heesen, Volker, E-mail: pcigan@alumni.nmt.edu [School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom); Collaboration: LITTLE THINGS Team

2016-01-15

We present far-infrared (FIR) spectral line observations of five galaxies from the Little Things sample: DDO 69, DDO 70, DDO 75, DDO 155, and WLM. While most studies of dwarfs focus on bright systems or starbursts due to observational constraints, our data extend the observed parameter space into the regime of low surface brightness dwarf galaxies with low metallicities and moderate star formation rates. Our targets were observed with Herschel at the [C ii] 158 μm, [O i] 63 μm, [O iii] 88 μm, and [N ii] 122 μm emission lines using the PACS Spectrometer. These high-resolution maps allow us for the first time to study the FIR properties of these systems on the scales of larger star-forming complexes. The spatial resolution in our maps, in combination with star formation tracers, allows us to identify separate photodissociation regions (PDRs) in some of the regions we observed. Our systems have widespread [C ii] emission that is bright relative to continuum, averaging near 0.5% of the total infrared (TIR) budget—higher than in solar-metallicity galaxies of other types. [N ii] is weak, suggesting that the [C ii] emission in our galaxies comes mostly from PDRs instead of the diffuse ionized interstellar medium (ISM). These systems exhibit efficient cooling at low dust temperatures, as shown by ([O i]+[C ii])/TIR in relation to 60 μm/100 μm, and low [O i]/[C ii] ratios which indicate that [C ii] is the dominant coolant of the ISM. We observe [O iii]/[C ii] ratios in our galaxies that are lower than those published for other dwarfs, but similar to levels noted in spirals.

Do the Herschel cold clouds in the Galactic halo embody its dark matter?

NARCIS (Netherlands)

Nieuwenhuizen, T.M.; van Heusden, E.F.G.; Liska, M.T.P.

2012-01-01

Recent Herschel/SPIRE (Spectral and Photometric Imaging Receiver) maps of the Small and Large Magellanic Clouds (SMC, LMC) exhibit, in each, thousands of clouds. Observed at 250 μm, they must be cold, T ~ 15 K, hence the name 'Herschel cold clouds' (HCCs). From the observed rotational velocity

Benchmark test of CP-PACS for lattice QCD

International Nuclear Information System (INIS)

Yoshie, Tomoteru

1996-01-01

The CP-PACS is a massively parallel computer dedicated for calculations in computational physics and will be in operation in the spring of 1996 at Center for Computational Physics, University of Tsukuba. In this paper, we describe the architecture of the CP-PACS and report the results of the estimate of the performance of the CP-PACS for typical lattice QCD calculations. (author)

Parents as Agents of Change (PAC in pediatric weight management: The protocol for the PAC randomized clinical trial

Directory of Open Access Journals (Sweden)

Ball Geoff D C

2012-08-01

Full Text Available Abstract Background There is an urgent need to develop and evaluate weight management interventions to address childhood obesity. Recent research suggests that interventions designed for parents exclusively, which have been named parents as agents of change (PAC approaches, have yielded positive outcomes for managing pediatric obesity. To date, no research has combined a PAC intervention approach with cognitive behavioural therapy (CBT to examine whether these combined elements enhance intervention effectiveness. This paper describes the protocol our team is using to examine two PAC-based interventions for pediatric weight management. We hypothesize that children with obesity whose parents complete a CBT-based PAC intervention will achieve greater reductions in adiposity and improvements in cardiometabolic risk factors, lifestyle behaviours, and psychosocial outcomes than children whose parents complete a psycho-education-based PAC intervention (PEP. Methods/Design This study is a pragmatic, two-armed, parallel, single-blinded, superiority, randomized clinical trial. The primary objective is to examine the differential effects of a CBT-based PAC vs PEP-based PAC intervention on children’s BMI z-score (primary outcome. Secondary objectives are to assess intervention-mediated changes in cardiometabolic, lifestyle, and psychosocial variables in children and parents. Both interventions are similar in frequency of contact, session duration, group facilitation, lifestyle behaviour goals, and educational content. However, the interventions differ insofar as the CBT-based intervention incorporates theory-based concepts to help parents link their thoughts, feelings, and behaviours; these cognitive activities are enabled by group leaders who possess formal training in CBT. Mothers and fathers of children (8–12 years of age; BMI ≥85th percentile are eligible to participate if they are proficient in English (written and spoken and agree for at least

PACS: Concepts and Trends

Science.gov (United States)

Bandon, David; Ratib, Osman; Lovis, Christian; Geissbuhler, Antoine

Picture Archiving and Communication Systems (PACS) are becoming part of the core components of today's infrastructure for digital radiology. In modern setting they also extend to the whole medical enterprise and integrate into the patient medical record. While local architectures may vary significantly, the major features such as image archiving and retrieval, workflow management, workstations and image acquisition and quality control systems constitute the key elements of such systems. PACS has also vocation to extend beyond the radiological images to become the common platform for hospital wide management of all images. The wireless access can contribute to expand the scope of image distribution.

Integrated RIS-PACS system

International Nuclear Information System (INIS)

Nishihara, Eitaro; Kura, Hiroyuki; Fukushima, Yuki

1994-01-01

We have developed an integrated RIS-PACS (radiology information system-picture archiving and communication system) system which supports examination, interpretation, and management in the diagnostic imaging department. The system was introduced in the Toshiba Hospital in May 1993, concurrently with the renewal of the hospital facilities. The integrated RIS-PACS system consists of a radiology information management system, and an image management system. The system supports wet (immediate) reading and chronological comparative reading using viewing workstation, enables routine operations to be performed in the diagnostic imaging department without film transportation, and contributes to the improvement of management efficiency in the department. (author)

PACS project management utilizing web-based tools

Science.gov (United States)

Patel, Sunil; Levin, Brad; Gac, Robert J., Jr.; Harding, Douglas, Jr.; Chacko, Anna K.; Radvany, Martin; Romlein, John R.

2000-05-01

As Picture Archiving and Communications Systems (PACS) implementations become more widespread, the management of deploying large, multi-facility PACS will become a more frequent occurrence. The tools and usability of the World Wide Web to disseminate project management information obviates time, distance, participant availability, and data format constraints, allowing for the effective collection and dissemination of PACS planning, implementation information, for a potentially limitless number of concurrent PACS sites. This paper will speak to tools, such as (1) a topic specific discussion board, (2) a 'restricted' Intranet, within a 'project' Intranet. We will also discuss project specific methods currently in use in a leading edge, regional PACS implementation concerning the sharing of project schedules, physical drawings, images of implementations, site-specific data, point of contacts lists, project milestones, and a general project overview. The individual benefits realized for the end user from each tool will also be covered. These details will be presented, balanced with a spotlight on communication as a critical component of any project management undertaking. Using today's technology, the web arguably provides the most cost and resource effective vehicle to facilitate the broad based, interactive sharing of project information.

Picture archiving and communication systems (PACS) for hospitals, a survey

International Nuclear Information System (INIS)

Haar Romeny, B.M. ter; Graaf, C.N. de; Waes, P.F.G.M. van; Rijk, P.P. van; Helder, J.C.; Valk, J.P.J. de

1985-01-01

In this article a survey is given for Picture Archiving and Communication Systems (PACS). Several aspects of PACS are treated, as image management, the introduction of the system, expenses etc. Special reference is made to the component parts of PACS: image stations, memory, network, software and coupling to the hospital information system. The introduction of PACS in Dutch hospitals is described. (Auth.)

Evaluation of a PACS workstation for interpreting body CT studies

International Nuclear Information System (INIS)

Franken, E.A.; Berbaum, K.S.; Honda, H.; McGuire, C.; Weis, R.R.; Barloon, T.

1989-01-01

This paper reports conventional hard-copy images from 266 body CT studies compared with those provided by a picture archiving and communication system (PACS) workstation. PACS images were evaluated before and after use of various image processing features. Most cases were depicted equally well, but in about one-fourth of the cases, diagnostic features were shown more clearly on PACS images. When PACS images were viewed first, a change in diagnosis after subsequent hardcopy inspection was infrequent, but when hard-copy images were viewed first, the results were converse. The image processing features of PACS were critical for its superior performance. The ability of a PACS to provide both image display and manipulation results in the superiority of that system

Clinical experience with PACS at Northwestern: year two

Science.gov (United States)

Channin, David S.; Hawkins, Rodney C.; Enzmann, Dieter R.

2001-08-01

We have previously described the PACS configuration at Northwestern Memorial Hospital (NMH). As opposed to an imaging modality, PACS is an evolving system that continuously grows and changes to meet the needs of the institution. The NMH PACS has grown significantly in the past year and has undergone significant architectural enhancements. This growth and evolutionary change will be described and discussed. The system now contains over 339,000 studies consisting of over 13 million images. There are now two short-term RAID storage units that provide for twice as much fast storage. There are also two magneto-optical disk jukeboxes providing long-term archive. We have deployed a redundant database to improve reliability of the system in the event of database failure. The number of modalities connected to the system has increased and will be summarized. Statistics describing utilization of the PACS will be shown. Lastly, we will discuss our plans for exploiting the application service provider model in our PACS environment.

Medical imaging, PACS, and imaging informatics: retrospective.

Science.gov (United States)

Huang, H K

2014-01-01

Historical reviews of PACS (picture archiving and communication system) and imaging informatics development from different points of view have been published in the past (Huang in Euro J Radiol 78:163-176, 2011; Lemke in Euro J Radiol 78:177-183, 2011; Inamura and Jong in Euro J Radiol 78:184-189, 2011). This retrospective attempts to look at the topic from a different angle by identifying certain basic medical imaging inventions in the 1960s and 1970s which had conceptually defined basic components of PACS guiding its course of development in the 1980s and 1990s, as well as subsequent imaging informatics research in the 2000s. In medical imaging, the emphasis was on the innovations at Georgetown University in Washington, DC, in the 1960s and 1970s. During the 1980s and 1990s, research and training support from US government agencies and public and private medical imaging manufacturers became available for training of young talents in biomedical physics and for developing the key components required for PACS development. In the 2000s, computer hardware and software as well as communication networks advanced by leaps and bounds, opening the door for medical imaging informatics to flourish. Because many key components required for the PACS operation were developed by the UCLA PACS Team and its collaborative partners in the 1980s, this presentation is centered on that aspect. During this period, substantial collaborative research efforts by many individual teams in the US and in Japan were highlighted. Credits are due particularly to the Pattern Recognition Laboratory at Georgetown University, and the computed radiography (CR) development at the Fuji Electric Corp. in collaboration with Stanford University in the 1970s; the Image Processing Laboratory at UCLA in the 1980s-1990s; as well as the early PACS development at the Hokkaido University, Sapporo, Japan, in the late 1970s, and film scanner and digital radiography developed by Konishiroku Photo Ind. Co. Ltd

Evolution of interstellar dust in light of Herschel Space Observatory data

International Nuclear Information System (INIS)

Arab, Heddy

2012-01-01

Interstellar dust grains are nanometer to micrometer sized particles. Although a weak proportion of the total interstellar mass is at solid state, dust plays a fundamental role in the evolution of the interstellar medium (ISM) and of the galaxy itself. Grains can be observed in the UV and visible wavelength through extinction whereas their emission is in the infrared to submillimeter range. Astrophysical observations combined to numerical models and laboratory studies of dust analogs improve our comprehension of the nature and the physics of interstellar grains. For example, evidence of dust evolution in the interstellar medium are now numerous, even if the physical processes responsible of this evolution are still poorly understood. Understanding how grains evolve with physical conditions requires observations of various environments. Photodissociation regions (PDRs) are zones of the ISM where the radiation field and the local density vary on short spatial scales (∼10''- 20''). Moreover the many gas tracers offer the opportunity to constraint efficiently the physical conditions within PDRs. Past missions such as ISO and Spitzer allow to study the evolution of dust in the near-Infrared range. At longer wavelengths, where the emission is dominated by the grains at thermal equilibrium with the radiation, instruments rarely resolved the spatial emission in PDRs. PACS and SPIRE instruments onboard Herschel Space Observatory provide spectro-photometric data between 70 and 500 μm. Their high spatial resolution (from 5 to 35 arcmin) makes these observations ideal for the study of dust evolution in PDRs. We present here an analysis of Herschel observations of three PDRs: the Orion Bar, the Horsehead and NGC 7023 East, characterized by different physical conditions. By combining these data with shorter wavelength observations from Spitzer, we can study the dust emission spectrum from 3.6 to 500 μm at different positions within the PDR. Intensity profiles are extracted

Numerical Study on Outflows in Seyfert Galaxies I: Narrow Line Region Outflows in NGC 4151

Energy Technology Data Exchange (ETDEWEB)

Mou, Guobin; Wang, Tinggui; Yang, Chenwei, E-mail: gbmou@ustc.edu.cn [CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Hefei 230026 (China)

2017-07-20

The origin of narrow line region (NLR) outflows remains unknown. In this paper, we explore the scenario in which these outflows are circumnuclear clouds driven by energetic accretion disk winds. We choose the well-studied nearby Seyfert galaxy NGC 4151 as an example. By performing 3D hydrodynamical simulations, we are able to reproduce the radial distributions of velocity, mass outflow rate, and kinetic luminosity of NLR outflows in the inner 100 pc deduced from spatial resolved spectroscopic observations. The demanded kinetic luminosity of disk winds is about two orders of magnitude higher than that inferred from the NLR outflows, but is close to the ultrafast outflows (UFO) detected in the X-ray spectrum and a few times lower than the bolometric luminosity of the Seyfert. Our simulations imply that the scenario is viable for NGC 4151. The existence of the underlying disk winds can be confirmed by their impacts on higher density ISM, e.g., shock excitation signs, and the pressure in NLR.

Numerical Study on Outflows in Seyfert Galaxies I: Narrow Line Region Outflows in NGC 4151

International Nuclear Information System (INIS)

Mou, Guobin; Wang, Tinggui; Yang, Chenwei

2017-01-01

The origin of narrow line region (NLR) outflows remains unknown. In this paper, we explore the scenario in which these outflows are circumnuclear clouds driven by energetic accretion disk winds. We choose the well-studied nearby Seyfert galaxy NGC 4151 as an example. By performing 3D hydrodynamical simulations, we are able to reproduce the radial distributions of velocity, mass outflow rate, and kinetic luminosity of NLR outflows in the inner 100 pc deduced from spatial resolved spectroscopic observations. The demanded kinetic luminosity of disk winds is about two orders of magnitude higher than that inferred from the NLR outflows, but is close to the ultrafast outflows (UFO) detected in the X-ray spectrum and a few times lower than the bolometric luminosity of the Seyfert. Our simulations imply that the scenario is viable for NGC 4151. The existence of the underlying disk winds can be confirmed by their impacts on higher density ISM, e.g., shock excitation signs, and the pressure in NLR.

Numerical Study on Outflows in Seyfert Galaxies I: Narrow Line Region Outflows in NGC 4151

Science.gov (United States)

Mou, Guobin; Wang, Tinggui; Yang, Chenwei

2017-07-01

The origin of narrow line region (NLR) outflows remains unknown. In this paper, we explore the scenario in which these outflows are circumnuclear clouds driven by energetic accretion disk winds. We choose the well-studied nearby Seyfert galaxy NGC 4151 as an example. By performing 3D hydrodynamical simulations, we are able to reproduce the radial distributions of velocity, mass outflow rate, and kinetic luminosity of NLR outflows in the inner 100 pc deduced from spatial resolved spectroscopic observations. The demanded kinetic luminosity of disk winds is about two orders of magnitude higher than that inferred from the NLR outflows, but is close to the ultrafast outflows (UFO) detected in the X-ray spectrum and a few times lower than the bolometric luminosity of the Seyfert. Our simulations imply that the scenario is viable for NGC 4151. The existence of the underlying disk winds can be confirmed by their impacts on higher density ISM, e.g., shock excitation signs, and the pressure in NLR.

Mathematical method for the study and teaching of stellar and protostellar structure

International Nuclear Information System (INIS)

Doorish, J.F.

1988-01-01

The purpose of this thesis is to develop a relatively simple yet effective method of teaching stellar and protostellar structure. There are four differential equations describing the structure of a star. These equations are linearly approximated in the following form: W = W 0 (1 ± wx). Here, W represents the pressure (P), temperature (T), mass (M), and/or luminosity (L) gradients within the star; W represents some initial value of these parameters expanded inwardly or outwardly from an initial point, r 0 ; and w represents what is called the Motz Dimensionless Variables (MDV) which are directly derivable from the above set of equations. They are dimensionless, so, in the expansion, W has the same units as w 0 . In the set of equations describing the MDV, if the surface of the star is expanded to larger values, representing earlier, and therefore, protostellar stages of the star, by theoretically halting accretion, no dynamical factors need to be considered. The set of equations describing a stellar structure in static equilibrium may then be used. This method was designed for college and early graduate students who have never before encountered the topic of stellar structure

The PAC-men revival : increasing need of PAC qualified colleagues

NARCIS (Netherlands)

Morren, J.; van der Heijden, S.

2012-01-01

More and more Protection, Automation, and Control (PAC) equipment is installed in the electricity (distribution) grid. For many employees of the network operators, the introduction of this equipment requires a change of mind, as this so-called secondary equipment is fundamentally different from the

Geometrical Acceptance Analysis for RPC PAC Trigger

CERN Document Server

Seo, Eunsung

2010-01-01

The CMS(Compact Muon Solenoid) is one of the four experiments that will analyze the collision results of the protons accelerated by the Large Hardron Collider(LHC) at CERN(Conseil Europen pour la Recherche Nuclaire). In case of the CMS experiment, the trigger system is divided into two stages : The Level-1 Trigger and High Level Trigger. The RPC(Resistive Plate Chamber) PAC(PAttern Comparator) Trigger system, which is a subject of this thesis, is a part of the Level-1 Muon Trigger System. Main task of the PAC Trigger is to identify muons, measures transverse momenta and select the best muon candidates for each proton bunch collision occurring every 25 ns. To calculate the value of PAC Trigger efficiency for triggerable muon, two terms of different efficiencies are needed ; acceptance efficiency and chamber efficiency. Main goal of the works described in this thesis is obtaining the acceptance efficiency of the PAC Trigger in each logical cone. Acceptance efficiency is a convolution of the chambers geometry an...

PACS quality control and automatic problem notifier

Science.gov (United States)

Honeyman-Buck, Janice C.; Jones, Douglas; Frost, Meryll M.; Staab, Edward V.

1997-05-01

One side effect of installing a clinical PACS Is that users become dependent upon the technology and in some cases it can be very difficult to revert back to a film based system if components fail. The nature of system failures range from slow deterioration of function as seen in the loss of monitor luminance through sudden catastrophic loss of the entire PACS networks. This paper describes the quality control procedures in place at the University of Florida and the automatic notification system that alerts PACS personnel when a failure has happened or is anticipated. The goal is to recover from a failure with a minimum of downtime and no data loss. Routine quality control is practiced on all aspects of PACS, from acquisition, through network routing, through display, and including archiving. Whenever possible, the system components perform self and between platform checks for active processes, file system status, errors in log files, and system uptime. When an error is detected or a exception occurs, an automatic page is sent to a pager with a diagnostic code. Documentation on each code, trouble shooting procedures, and repairs are kept on an intranet server accessible only to people involved in maintaining the PACS. In addition to the automatic paging system for error conditions, acquisition is assured by an automatic fax report sent on a daily basis to all technologists acquiring PACS images to be used as a cross check that all studies are archived prior to being removed from the acquisition systems. Daily quality control is preformed to assure that studies can be moved from each acquisition and contrast adjustment. The results of selected quality control reports will be presented. The intranet documentation server will be described with the automatic pager system. Monitor quality control reports will be described and the cost of quality control will be quantified. As PACS is accepted as a clinical tool, the same standards of quality control must be established

Process development and fabrication for sphere-pac fuel rods

International Nuclear Information System (INIS)

Welty, R.K.; Campbell, M.H.

1981-06-01

Uranium fuel rods containing sphere-pac fuel have been fabricated for in-reactor tests and demonstrations. A process for the development, qualification, and fabrication of acceptable sphere-pac fuel rods is described. Special equipment to control fuel contamination with moisture or air and the equipment layout needed for rod fabrication is described and tests for assuring the uniformity of the fuel column are discussed. Fuel retainers required for sphere-pac fuel column stability and instrumentation to measure fuel column smear density are described. Results of sphere-pac fuel rod fabrication campaigns are reviewed and recommended improvements for high throughput production are noted

STAR CLUSTER FORMATION WITH STELLAR FEEDBACK AND LARGE-SCALE INFLOW

International Nuclear Information System (INIS)

Matzner, Christopher D.; Jumper, Peter H.

2015-01-01

During star cluster formation, ongoing mass accretion is resisted by stellar feedback in the form of protostellar outflows from the low-mass stars and photo-ionization and radiation pressure feedback from the massive stars. We model the evolution of cluster-forming regions during a phase in which both accretion and feedback are present and use these models to investigate how star cluster formation might terminate. Protostellar outflows are the strongest form of feedback in low-mass regions, but these cannot stop cluster formation if matter continues to flow in. In more massive clusters, radiation pressure and photo-ionization rapidly clear the cluster-forming gas when its column density is too small. We assess the rates of dynamical mass ejection and of evaporation, while accounting for the important effect of dust opacity on photo-ionization. Our models are consistent with the census of protostellar outflows in NGC 1333 and Serpens South and with the dust temperatures observed in regions of massive star formation. Comparing observations of massive cluster-forming regions against our model parameter space, and against our expectations for accretion-driven evolution, we infer that massive-star feedback is a likely cause of gas disruption in regions with velocity dispersions less than a few kilometers per second, but that more massive and more turbulent regions are too strongly bound for stellar feedback to be disruptive

[Economic and organizational evaluation of an imaging network (PACS)].

Science.gov (United States)

Charvet-Protat, S; Thoral, F

1998-12-01

Over the last twenty years, imaging modalities featuring new image production methods (ultrasound, nuclear magnetic resonance, etc.) have appeared on the market. Nevertheless, conventional radiology still accounts for 70% of the image examinations carried out in most western countries, including France. The conventional radiological image is in the process of evolving from analog to digital form. Digitalization of radiology means that image acquisition, archiving and distribution functions that were previously carried out by hand can now be automated using a Picture Archiving and Communication System. Decision-makers are having to decide whether or not to promote the development of PACS which, while they considerably modernize the way in which images are managed, also require heavy capital outlays. A critical appraisal of the literature allowed us to evaluate the relative cost and the efficiency of these image networks in comparison with film-based archiving and communication systems. It is clear from the economic evaluation that a PACS strategy involves greater costs than a film system. While PACS systems do generate savings on film and on storage space and obviate the need for certain staff, these savings do not offset the extra equipment and maintenance costs. This situation is likely to persist for some years yet, even when future price reductions are taken into account. The objective of this new radiological information management method is to improve organizational efficiency and hospital productivity. However, the economic evaluations that have been published to date are cost studies which do not take the efficiency criterion into account. A number of potential organizational benefits such as the fact that medical decisions can be made more quickly or that the average length of hospital stays can be reduced, are often claimed for PACS. However, for methodological reasons, these results cannot be generalised to cover all PACS. It is difficult to compare PACS

Status of the CP-PACS Project

International Nuclear Information System (INIS)

Ukawa, A.

1995-01-01

The CP-PACS Project, which started in April 1992, is a five-year plan to develop a massively parallel computer for carrying out research in computational physics with primary emphasis on lattice QCD. This article describes the architectural design of the CP-PACS computer, the entire computing system including the front end and mass storage, and results of benchmarks for the expected performance for lattice QCD applications. ((orig.))

IHE, Solution for integration of information systems and PACS

Directory of Open Access Journals (Sweden)

Milad Janghorban Lariche

2014-10-01

Full Text Available PACS is used as a way to store images and matches well with the workflow in the radiology department and can spread to other parts of hospital. Integration with other PACS and other hospital systems like radiology information system (RIS, hospital information system (HIS, and electronic patient records has been completely done, but there are still problems. PACS also provide good conditions for setting up Tele-radiology. The next step for PACS is where hospitals and health care organizations share photos in integrated electronic patient record. Among the different ways for sharing photos between different hospitals, IHE (integrating the health care enterprise standard indexes the cross-enterprise document sharing profile (XDS and allows sharing photos from various hospitals even if their PACS has different brands and different vendors. Application of XDS is useful for sharing images between health care organizations without duplicating them in a central archive. Images need to be indexed in a central registry. In the XDS profile, IHE defines an indexing mechanism for printing and indexing images in the central document registry. IHE also defines mechanisms to be used by each hospital to retrieve images, regardless of storing them in hospital PACS.

Fusion breeder sphere - PAC blanket design

International Nuclear Information System (INIS)

Sullivan, J.D.; Palmer, B.J.F.

1987-11-01

There is a considerable world-wide effort directed toward the production of materials for fusion reactors. Many ceramic fabrication groups are working on making lithium ceramics in a variety of forms, to be incorporated into the tritium breeding blanket which will surround the fusion reactor. Current blanket designs include ceramic in either monolithic or packed sphere bed (sphere-pac) forms. The major thrust at AECL is the production of lithium aluminate spheres to be incorporated in a sphere-pac bed. Contemporary studies on breeder blanket design offer little insight into the requirements on the sizes of the spheres. This study examined the parameters which determine the properties of pressure drop and coolant requirements. It was determined that an optimised sphere-pac bed would be composed of two diameters of spheres: 75 weight % at 3 mm and 25 weight % at 0.3 mm

Web based emergency room PACS

International Nuclear Information System (INIS)

Cha, Soon Joo; Cheon, Yong Kyung; Choi, Sung Woo Kim

2005-01-01

We wished to develop the web based Picture Archiving and Communication System in the emergency room for early decision making in emergency treatment planning at a full PACS Hospital. The program tools were Microsoft Visual Studio 6.0 - Visual C++ 6.0, and the Microsoft SQL 7.0 under the Microsoft Windows 2000 server operation system. The achievement of images was performed by an auto transport program installed in the ER and the radiology department. The average compression rates were 5:1 for CT and MR, and 20:1 for CR with JPEG 2000 lossy compression. All the images were stored on hard disk for 3 months. The patients' information was displayed for 2 weeks for reducing the security risk. For interdepartmental consultation, patient query by patient hospital number was available. Our Web based ER PACS could be useful system for early decision making for treatment planning in the emergency room because it reduces the risk factors for the security of the Web Paces by using a system independent from PACS in the hospital and minimizing the information patients

Web based emergency room PACS

Energy Technology Data Exchange (ETDEWEB)

Cha, Soon Joo; Cheon, Yong Kyung; Choi, Sung Woo Kim [Ilsan Paik Hospital, Inje University, Seoul (Korea, Republic of)] (and others)

2005-07-15

We wished to develop the web based Picture Archiving and Communication System in the emergency room for early decision making in emergency treatment planning at a full PACS Hospital. The program tools were Microsoft Visual Studio 6.0 - Visual C++ 6.0, and the Microsoft SQL 7.0 under the Microsoft Windows 2000 server operation system. The achievement of images was performed by an auto transport program installed in the ER and the radiology department. The average compression rates were 5:1 for CT and MR, and 20:1 for CR with JPEG 2000 lossy compression. All the images were stored on hard disk for 3 months. The patients' information was displayed for 2 weeks for reducing the security risk. For interdepartmental consultation, patient query by patient hospital number was available. Our Web based ER PACS could be useful system for early decision making for treatment planning in the emergency room because it reduces the risk factors for the security of the Web Paces by using a system independent from PACS in the hospital and minimizing the information patients.

Why PACS is no longer a four-letter word.

Science.gov (United States)

Chopra, R M

2000-01-01

The real value of PACS is not realized until widespread adoption exists among physicians other than interpreting radiologists. Referring physicians at the office level, in the operating room and in other departments must be willing to embrace the reading of images on monitors. That takes time. The payoff for a PACS system is therefore not realized until sometime in the future. Given the huge up-front capital expenditure required of PACS solutions, it is no wonder that the decision has historically been a difficult one to make. Enter the application service provider (ASP). The marriage of the ASP model to PACS seems to be one of the true "killer apps" currently available in the healthcare technology space. An ASP can host and maintain the software inherent in PACS solutions. Images are centrally archived over the short-, medium-, and long-term timeframe, utilizing state-of-art data management facilities. Some ASPs also provide the necessary bandwidth to office sites and the small amount of hardware that is required onsite, such as viewing stations or monitors. Costs for Internet-based image management under the ASP model rely on a pay-as-you-go formula, which may include all software, support, required hardware and bandwidth as part of the service. There may be a minor up-front fee for installation. The ASP pricing model eliminates the huge gamble an organization takes on "big iron" PACS purchases. Those benefits rely on the first rule of finance: a dollar today is worth more than a dollar tomorrow. PACS and ASPs were made for one another. Because the financial benefits of PACS are realized over time, the timing of cash flows is extremely important. Other benefits inherent in the ASP model such as scalability, diminished need for IT personnel, software version integrity and better pricing because of economies of scale are attractive also.

REGIONAL VARIATIONS IN THE DENSE GAS HEATING AND COOLING IN M51 FROM HERSCHEL FAR-INFRARED SPECTROSCOPY

Energy Technology Data Exchange (ETDEWEB)

Parkin, T. J.; Wilson, C. D.; Schirm, M. R. P.; Foyle, K. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1 (Canada); Baes, M.; De Looze, I. [Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281 S9, B-9000 Gent (Belgium); Boquien, M.; Boselli, A. [Laboratoire d' Astrophysique de Marseille-LAM, Université d' Aix-Marseille and CNRS, UMR7326, 38 rue F. Joliot-Curie, F-13388 Marseille Cedex 13 (France); Cooray, A. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Cormier, D. [Institut für Theoretische Astrophysik, Zentrum für Astronomie der Universität Heidelberg, Albert-Ueberle Str. 2, D-69120 Heidelberg (Germany); Karczewski, O. Ł. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Lebouteiller, V.; Madden, S. C.; Sauvage, M. [CEA, Laboratoire AIM, Irfu/SAp, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Roussel, H. [Institut d' Astrophysique de Paris, UMR7095 CNRS, Université Pierre and Marie Curie, 98 bis Boulevard Arago, F-75014 Paris (France); Spinoglio, L., E-mail: parkintj@mcmaster.ca [Istituto di Astrofisica e Planetologia Spaziali, INAF-IAPS, Via Fosso del Cavaliere 100, I-00133 Roma (Italy)

2013-10-20

We present Herschel PACS and SPIRE spectroscopy of the most important far-infrared cooling lines in M51, [C II](158 μm), [N II](122 and 205 μm), [O I](63 and 145 μm), and [O III](88 μm). We compare the observed flux of these lines with the predicted flux from a photon-dominated region model to determine characteristics of the cold gas such as density, temperature, and the far-ultraviolet (FUV) radiation field, G{sub 0}, resolving details on physical scales of roughly 600 pc. We find an average [C II]/F{sub TIR} of 4 × 10{sup –3}, in agreement with previous studies of other galaxies. A pixel-by-pixel analysis of four distinct regions of M51 shows a radially decreasing trend in both the FUV radiation field, G{sub 0}, and the hydrogen density, n, peaking in the nucleus of the galaxy, and then falling off out to the arm and interarm regions. We see for the first time that the FUV flux and gas density are similar in the differing environments of the arm and interarm regions, suggesting that the inherent physical properties of the molecular clouds in both regions are essentially the same.

The first results from the Herschel-HIFI mission

NARCIS (Netherlands)

van der Tak, Floris

2012-01-01

This paper contains a summary of the results from the first years of observations with the HIFI instrument onboard ESA's Herschel space observatory. The paper starts by outlining the goals and possibilities of far-infrared and submillimeter astronomy, the limitations of the Earth's atmosphere, and

The H2CO abundance in the inner warm regions of low mass protostellar envelopes

NARCIS (Netherlands)

Maret, S; Ceccarelli, C; Caux, E; Tielens, A. G. G. M.; Jorgensen, JK; van Dishoeck, E; Bacmann, A; Castets, A; Lefloch, B; Loinard, L; Parise, B; Schoier, FL

We present a survey of the formaldehyde emission in a sample of eight Class 0 protostars obtained with the IRAM and JCMT millimeter telescopes. The range of energies of the observed transitions allows us to probe the physical and chemical conditions across the protostellar envelopes. The data have

The HIFI spectral survey of AFGL 2591 (CHESS). III. Chemical structure of the protostellar envelope

NARCIS (Netherlands)

Kaźmierczak-Barthel, M.; Semenov, D. A.; van der Tak, F. F. S.; Chavarría, L.; van der Wiel, M. H. D.

Aims: The aim of this work is to understand the richness of chemical species observed in the isolated high-mass envelope of AFGL 2591, a prototypical object for studying massive star formation. Methods: Based on HIFI and JCMT data, the molecular abundances of species found in the protostellar

The future of PACS in healthcare enterprises

International Nuclear Information System (INIS)

Faggioni, Lorenzo; Neri, Emanuele; Castellana, Carlo; Caramella, Davide; Bartolozzi, Carlo

2011-01-01

Picture Archiving and Communication System (PACS), which was originally designed as a tool for facilitating radiologists in interpreting images more efficiently, is evolving into a hospital-integrated system storing diagnostic imaging information that often reaches far beyond Radiology. The continuous evolution of PACS technology has led to a gradual broadening of its applications, ranging from teleradiology to CAD (Computer-Assisted Diagnosis) and multidimensional imaging, and is moving into the direction of providing access to image data outside the Radiology department, so to reach all the branches of the healthcare enterprise. New perspectives have been created thanks to new technologies (such as holographic media and GRID computing) that are likely due to expand PACS-based applications even further, improving patient care and enhancing overall productivity.

Integration Of An MR Image Network Into A Clinical PACS

Science.gov (United States)

Ratib, Osman M.; Mankovich, Nicholas J.; Taira, Ricky K.; Cho, Paul S.; Huang, H. K.

1988-06-01

A direct link between a clinical pediatric PACS module and a FONAR MRI image network was implemented. The original MR network combines together the MR scanner, a remote viewing station and a central archiving station. The pediatric PACS directly connects to the archiving unit through an Ethernet TCP-IP network adhering to FONAR's protocol. The PACS communication software developed supports the transfer of patient studies and the patient information directly from the MR archive database to the pediatric PACS. In the first phase of our project we developed a package to transfer data between a VAX-111750 and the IBM PC I AT-based MR archive database through the Ethernet network. This system served as a model for PACS-to-modality network communication. Once testing was complete on this research network, the software and network hardware was moved to the clinical pediatric VAX for full PACS integration. In parallel to the direct transmission of digital images to the Pediatric PACS, a broadband communication system in video format was developed for real-time broadcasting of images originating from the MR console to 8 remote viewing stations distributed in the radiology department. These analog viewing stations allow the radiologists to directly monitor patient positioning and to select the scan levels during a patient examination from remote locations in the radiology department. This paper reports (1) the technical details of this implementation, (2) the merits of this network development scheme, and (3) the performance statistics of the network-to-PACS interface.

Project plan for PACS networking construction and cabling

International Nuclear Information System (INIS)

Luo Min; Wang Xiaolin; Luo Song; Lei Wenyong; Wang Xuejian; Wen Hongyue; Wu Hongxing

2002-01-01

Objective: To meet the networking requirement of the heave data flow, load balance, and potential networking storm during expanding the application of PACS. Methods: Intel Net Structure 480T Giga Switch was used as main switch and connected to each building by optical channel at 1 Giga speed to archive 100 MB/s to each port. At the same time, the in dependence of the original networking construction was physically kept. The layer 3 and 4 switchers was used as load balance to reduce the heavy load of the networking, and all the cabling for PACS used the super CAT5 along with the Intel Net Structure 1520 to prepare for the potential networking storm. Results: An advanced intranet was set up to fully meet the high standard requirement of PACS. The good foundation for upgrading the whole networking system to 1 Giga application was built for realized share and transmission of image, information, and patient data within the hospital. The base was established for the standardized management of the hospital. Conclusion: Good planning is the 1 st step in setting up PACS and the equipment are the platform to run PACS and all kinds of HIS. The networking construction is the foundation of e-hospitals

How bright planets became dim stars: planetary speculations in John Herschel's double star astronomy.

Science.gov (United States)

Case, Stephen

2014-03-01

Previous research on the origins of double star astronomy in the early nineteenth century emphasized the role mathematical methods and instrumentation played in motivating early observations of these objects. The work of the British astronomer John Herschel, however, shows that questions regarding the physical nature of double stars were also important. In particular, an analysis of John Herschel's early work on double stars illustrates the way in which speculations regarding these objects were shaped by assumptions of the properties of stars themselves. For Herschel, a major consideration in double star astronomy was distinguishing between types of double stars. Optical doubles were useful in determining parallax while binary doubles were not. In practice, classification of a specific double star pair into one of these categories was based on the assumption that stars were of approximately the same luminosity and thus differences in relative brightness between stars were caused by difference in distances. Such assumptions, though ultimately abandoned, would lead Herschel in the 1830s to advance the possibility that the dim companion stars in certain double star pairs were not stars at all but in fact planets. Copyright © 2014 Elsevier Ltd. All rights reserved.

THE FIRST Hi-GAL OBSERVATIONS OF THE OUTER GALAXY: A LOOK AT STAR FORMATION IN THE THIRD GALACTIC QUADRANT IN THE LONGITUDE RANGE 216. Degree-Sign 5 {approx}< l {approx}< 225. Degree-Sign 5

Energy Technology Data Exchange (ETDEWEB)

Elia, D.; Molinari, S.; Schisano, E.; Pestalozzi, M.; Benedettini, M.; Di Giorgio, A. M.; Pezzuto, S.; Rygl, K. L. J. [Istituto di Astrofisica e Planetologia Spaziali-INAF, Via Fosso del Cavaliere 100, I-00133 Roma (Italy); Fukui, Y.; Hayakawa, T.; Yamamoto, H. [Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602 (Japan); Olmi, L. [Osservatorio Astrofisico di Arcetri-INAF, Largo E. Fermi 5, I-50125 Firenze (Italy); Veneziani, M. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Schneider, N.; Piazzo, L. [IRFU/SAp CEA/DSM, Laboratoire AIM CNRS, Universit Paris Diderot, F-91191 Gif-sur-Yvette (France); Ikhenaode, D. [DIET-Dipartimento di Ingegneria dell' Informazione, Elettronica e Telecomunicazioni, Universita di Roma La Sapienza, via Eudossina 18, I-00184 Roma (Italy); Mizuno, A. [Solar-Terrestrial Environment Laboratory, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Onishi, T. [Department of Physical Science, Osaka Prefecture University, Sakai, Osaka 599-8531 (Japan); Polychroni, D. [Department of Astrophysics, Astronomy and Mechanics, Faculty of Physics, University of Athens, Panepistimiopolis, 15784 Zografos, Athens (Greece); Maruccia, Y., E-mail: davide.elia@iaps.inaf.it [Dipartimento di Matematica e Fisica, Universita del Salento, CP 193, I-73100 Lecce (Italy)

2013-07-20

We present the first Herschel PACS and SPIRE photometric observations in a portion of the outer Galaxy (216. Degree-Sign 5 {approx}< l {approx}< 225. Degree-Sign 5 and -2 Degree-Sign {approx}< b {approx}< 0 Degree-Sign ) as a part of the Hi-GAL survey. The maps between 70 and 500 {mu}m, the derived column density and temperature maps, and the compact source catalog are presented. NANTEN CO(1-0) line observations are used to derive cloud kinematics and distances so that we can estimate distance-dependent physical parameters of the compact sources (cores and clumps) having a reliable spectral energy distribution that we separate into 255 proto-stellar and 688 starless sources. Both typologies are found in association with all the distance components observed in the field, up to {approx}5.8 kpc, testifying to the presence of star formation beyond the Perseus arm at these longitudes. Selecting the starless gravitationally bound sources, we identify 590 pre-stellar candidates. Several sources of both proto- and pre-stellar nature are found to exceed the minimum requirement for being compatible with massive star formation based on the mass-radius relation. For the pre-stellar sources belonging to the Local arm (d {approx}< 1.5 kpc) we study the mass function whose high-mass end shows a power law N(log M){proportional_to}M {sup -1.0{+-}0.2}. Finally, we use a luminosity versus mass diagram to infer the evolutionary status of the sources, finding that most of the proto-stellar sources are in the early accretion phase (with some cases compatible with a Class I stage), while for pre-stellar sources, in general, accretion has not yet started.

SIGNATURES OF GRAVITATIONAL INSTABILITY IN RESOLVED IMAGES OF PROTOSTELLAR DISKS

Energy Technology Data Exchange (ETDEWEB)

Dong, Ruobing [Lawrence Berkeley National Lab, Berkeley, CA 94720 (United States); Vorobyov, Eduard [Department of Astrophysics, The University of Vienna, Vienna, A-1180 (Austria); Pavlyuchenkov, Yaroslav [Institute of Astronomy, Russian Academy of Sciences, Moscow (Russian Federation); Chiang, Eugene [Department of Astronomy, University of California at Berkeley, Berkeley, CA 94720 (United States); Liu, Hauyu Baobab, E-mail: rdong2013@berkeley.edu [European Southern Observatory (ESO), Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany)

2016-06-01

Protostellar (class 0/I) disks, which have masses comparable to those of their nascent host stars and are fed continuously from their natal infalling envelopes, are prone to gravitational instability (GI). Motivated by advances in near-infrared (NIR) adaptive optics imaging and millimeter-wave interferometry, we explore the observational signatures of GI in disks using hydrodynamical and Monte Carlo radiative transfer simulations to synthesize NIR scattered light images and millimeter dust continuum maps. Spiral arms induced by GI, located at disk radii of hundreds of astronomical units, are local overdensities and have their photospheres displaced to higher altitudes above the disk midplane; therefore, arms scatter more NIR light from their central stars than inter-arm regions, and are detectable at distances up to 1 kpc by Gemini/GPI, VLT/SPHERE, and Subaru/HiCIAO/SCExAO. In contrast, collapsed clumps formed by disk fragmentation have such strong local gravitational fields that their scattering photospheres are at lower altitudes; such fragments appear fainter than their surroundings in NIR scattered light. Spiral arms and streamers recently imaged in four FU Ori systems at NIR wavelengths resemble GI-induced structures and support the interpretation that FUors are gravitationally unstable protostellar disks. At millimeter wavelengths, both spirals and clumps appear brighter in thermal emission than the ambient disk and can be detected by ALMA at distances up to 0.4 kpc with one hour integration times at ∼0.″1 resolution. Collapsed fragments having masses ≳1 M {sub J} can be detected by ALMA within ∼10 minutes.

LONG-TERM EVOLUTION OF PROTOSTELLAR AND PROTOPLANETARY DISKS. I. OUTBURSTS

International Nuclear Information System (INIS)

Zhu Zhaohuan; Hartmann, Lee; Gammie, Charles F.; Book, Laura G.; Simon, Jacob B.; Engelhard, Eric

2010-01-01

As an initial investigation into the long-term evolution of protostellar disks, we explore the conditions required to explain the large outbursts of disk accretion seen in some young stellar objects. We use one-dimensional time-dependent disk models with a phenomenological treatment of the magnetorotational instability (MRI) and gravitational torques to follow disk evolution over long timescales. Comparison with our previous two-dimensional disk model calculations indicates that the neglect of radial effects and two-dimensional disk structure in the one-dimensional case makes only modest differences in the results; this allows us to use the simpler models to explore parameter space efficiently. We find that the mass infall rates typically estimated for low-mass protostars generally result in AU-scale disk accretion outbursts, as predicted by our previous analysis. We also confirm quasi-steady accretion behavior for high mass infall rates if the values of α-parameter for the MRI are small, while at this high accretion rate convection from the thermal instability may lead to some variations. We further constrain the combinations of the α-parameter and the MRI critical temperature, which can reproduce observed outburst behavior. Our results suggest that dust sublimation may be connected with full activation of the MRI. This is consistent with the idea that small dust captures ions and electrons to suppress the MRI. In a companion paper, we will explore both long-term outburst and disk evolution with this model, allowing for infall from protostellar envelopes with differing angular momenta.

bond activation and catalysis by Ru -pac complexes

Indian Academy of Sciences (India)

and their reactivity towards oxidation of a few organic compounds. Keywords. Kinetics; catalysis; -O–O- bond activation; Ru-pac complex; oxidation. 1. Introduction. Ru-pac complexes exhibit catalytic properties,1 in homogeneous conditions in the presence of oxygen atom donors, that mimic the biological enzymatic oxi-.

PACS in Töölö hospital.

Science.gov (United States)

Kinnunen, J; Pohjonen, H

2001-07-01

A 3-year PACS project was started in 1997 and completed in 1999 with filmless radiology and surgery. An efficient network for transferring images provides the infrastructure for integration of different distributed imaging systems and enables efficient handling of all patient-related information on one display station. Because of the need for high-speed communications and the massive amount of image data transferred in radiology, ATM (25, 155 Mbit/s) was chosen to be the main technology used. Both hardware and software redundancy of the system have been carefully planned. The size of the Dicom image library utilizing MO discs is currently 1.2 TB with 300 GB RAID capacity. For the increasing amount of teleradiologic consultations, a special Dicom gateway is planned. It allows a centralized and resilient handling and routing of received images around the hospital. Hospital-wide PACS has already improved the speed and quality of patient care by providing instant access to diagnostic information at multiple locations simultaneously. The benefits of PACS are considered from the viewpoint of the entire hospital: PACS offers a method for efficiently transporting patient-related images and reports to the referring physicians.

Design and optimizing factors of PACS network architecture

International Nuclear Information System (INIS)

Tao Yonghao; Miao Jingtao

2001-01-01

Objective: Exploring the design and optimizing factors of picture archiving and communication system (PACS) network architecture. Methods: Based on the PACS of shanghai first hospital to performed the measurements and tests on the requirements of network bandwidth and transmitting rate for different PACS functions and procedures respectively in static and dynamic network traffic situation, utilizing the network monitoring tools which built-in workstations and provided by Windows NT. Results: No obvious difference between switch equipment and HUB when measurements and tests implemented in static situation except route which slow down the rate markedly. In dynamic environment Switch is able to provide higher bandwidth utilizing than HUB and local system scope communication achieved faster transmitting rate than global system. Conclusion: The primary optimizing factors of PACS network architecture design include concise network topology and disassemble tremendous global traffic to multiple distributed local scope network communication to reduce the traffic of network backbone. The most important issue is guarantee essential bandwidth for diagnosis procedure of medical imaging

The sphere-PAC fuel code 'SPHERE-3'

International Nuclear Information System (INIS)

Wallin, H.

2000-01-01

Sphere-PAC fuel is an advanced nuclear fuel, in which the cladding tube is filled with small fuel spheres instead of the more usual fuel pellets. At PSI, the irradiation behaviour of sphere-PAC fuel is calculated using the computer code SPHERE-3. The paper describes the present status of the SPHERE-3 code, and some results of the qualification process against experimental data. (author)

The sphere-pac fuel code 'SPHERE-3'

International Nuclear Information System (INIS)

Wallin, H.; Nordstroem, L.A.; Hellwig, C.

2001-01-01

Sphere-pac fuel is an advanced nuclear fuel, in which the cladding tube is filled with small fuel spheres instead of the more usual fuel pellets. At PSI, the irradiation behaviour of sphere-pac fuel is calculated using the computer code SPHERE-3. The paper describes the present status of the SPHERE-3 code, and some results of the qualification process against experimental data. (author)

Herschel/HIFI observations of high-J CO lines in the NGC 1333 low-mass star-forming region

DEFF Research Database (Denmark)

Yildiz, U. A.; van Dishoeck, E. F.; Kristensen, L. E.

2010-01-01

Herschel/HIFI observations of high-J lines (up to Ju = 10) of 12CO, 13CO and C18O are presented toward three deeply embedded low-mass protostars, NGC 1333 IRAS 2A, IRAS 4A, and IRAS 4B, obtained as part of the Water In Star-forming regions with Herschel (WISH) key program. The spectrally-resolved......Herschel/HIFI observations of high-J lines (up to Ju = 10) of 12CO, 13CO and C18O are presented toward three deeply embedded low-mass protostars, NGC 1333 IRAS 2A, IRAS 4A, and IRAS 4B, obtained as part of the Water In Star-forming regions with Herschel (WISH) key program. The spectrally....... Their intensities require a jump in the CO abundance at an evaporation temperature around 25 K, thus providing new direct evidence for a CO ice evaporation zone around low-mass protostars. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia...... and with important participation from NASA.Appendices and acknowledgements (pages 5 to 7) are only available in electronic form at http://www.aanda.org...

ON THE NATURE OF THE ENIGMATIC OBJECT IRAS 19312+1950: A RARE PHASE OF MASSIVE STAR FORMATION?

Energy Technology Data Exchange (ETDEWEB)

Cordiner, M. A.; Charnley, S. B.; Milam, S. N. [Astrochemistry Laboratory, NASA Goddard Space Flight Center, Code 691, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Boogert, A. C. A. [Universities Space Research Association, Stratospheric Observatory for Infrared Astronomy, NASA Ames Research Center, MS 232-11, Moffett Field, CA 94035 (United States); Justtanont, K.; Wirström, E. S. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-439 92, Onsala (Sweden); Cox, N. L. J. [Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D, bus 2401, B-3001, Leuven (Belgium); Smith, R. G. [School of Physical, Environmental and Mathematical Sciences, The University of New South Wales, Australian Defence Force Academy, Canberra ACT 2600 (Australia); Tielens, A. G. G. M. [Leiden Observatory, University of Leiden, P.O. Box 9513, NL-2300 RA Leiden (Netherlands); Keane, J. V., E-mail: martin.cordiner@nasa.gov [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States)

2016-09-01

IRAS 19312+1950 is a peculiar object that has eluded firm characterization since its discovery, with combined maser properties similar to an evolved star and a young stellar object (YSO). To help determine its true nature, we obtained infrared spectra of IRAS 19312+1950 in the range 5–550 μ m using the Herschel and Spitzer space observatories. The Herschel PACS maps exhibit a compact, slightly asymmetric continuum source at 170 μ m, indicative of a large, dusty circumstellar envelope. The far-IR CO emission line spectrum reveals two gas temperature components: ≈0.22 M {sub ⊙} of material at 280 ± 18 K, and ≈1.6 M {sub ⊙} of material at 157 ± 3 K. The O i 63 μ m line is detected on-source but no significant emission from atomic ions was found. The HIFI observations display shocked, high-velocity gas with outflow speeds up to 90 km s{sup −1} along the line of sight. From Spitzer spectroscopy, we identify ice absorption bands due to H{sub 2}O at 5.8 μ m and CO{sub 2} at 15 μ m. The spectral energy distribution is consistent with a massive, luminous (∼2 × 10{sup 4} L {sub ⊙}) central source surrounded by a dense, warm circumstellar disk and envelope of total mass ∼500–700 M {sub ⊙}, with large bipolar outflow cavities. The combination of distinctive far-IR spectral features suggest that IRAS 19312+1950 should be classified as an accreting, high-mass YSO rather than an evolved star. In light of this reclassification, IRAS 19312+1950 becomes only the fifth high-mass protostar known to exhibit SiO maser activity, and demonstrates that 18 cm OH maser line ratios may not be reliable observational discriminators between evolved stars and YSOs.

On the Nature of the Enigmatic Object IRAS 19312+1950: A Rare Phase of Massive Star Formation?

Science.gov (United States)

Cordiner, M. A.; Boogert, A. C. A.; Charnley, S. B.; Justtanont, K.; Cox, N. L. J.; Smith, R. G.; Tielens, A. G. G. M.; Wirstrom, E. S.; Milam, S. N.; Keane, J. V.

2016-01-01

IRAS?19312+1950 is a peculiar object that has eluded firm characterization since its discovery, with combined maser properties similar to an evolved star and a young stellar object (YSO). To help determine its true nature, we obtained infrared spectra of IRAS?19312+1950 in the range 5-550 microns using the Herschel and Spitzer space observatories. The Herschel PACS maps exhibit a compact, slightly asymmetric continuum source at 170 microns, indicative of a large, dusty circumstellar envelope. The far-IR CO emission line spectrum reveals two gas temperature components: approx. = 0.22 Stellar Mass of material at 280+/-18 K, and ˜1.6 Me of material at 157+/-3 K. The OI 63 micron line is detected on-source but no significant emission from atomic ions was found. The HIFI observations display shocked, high-velocity gas with outflow speeds up to 90 km/s along the line of sight. From Spitzer spectroscopy, we identify ice absorption bands due to H2O at 5.8 microns and CO2 at 15 microns. The spectral energy distribution is consistent with a massive, luminous (approx. 2 × 10(exp 4) Stellar Luminosity) central source surrounded by a dense, warm circumstellar disk and envelope of total mass approx. 500-700 Stellar Mass with large bipolar outflow cavities. The combination of distinctive far-IR spectral features suggest that IRAS19312+1950 should be classified as an accreting, high-mass YSO rather than an evolved star. In light of this reclassification, IRAS19312+1950 becomes only the fifth high-mass protostar known to exhibit SiO maser activity, and demonstrates that 18 cm OH maser line ratios may not be reliable observational discriminators between evolved stars and YSOs.

[PACS-based endoscope image acquisition workstation].

Science.gov (United States)

Liu, J B; Zhuang, T G

2001-01-01

A practical PACS-based Endoscope Image Acquisition Workstation is here introduced. By a Multimedia Video Card, the endoscope video is digitized and captured dynamically or statically into computer. This workstation realizes a variety of functions such as the endoscope video's acquisition and display, as well as the editing, processing, managing, storage, printing, communication of related information. Together with other medical image workstation, it can make up the image sources of PACS for hospitals. In addition, it can also act as an independent endoscopy diagnostic system.

PACS--and beyond. A journey to the digital promised land.

Science.gov (United States)

Viau, Mark A

2004-01-01

A successful picture archiving and communication system (PACS) integration depends on much more than the technology; marketing also plays a large role. This fact was evident from the inception of the PACS project at Boca Raton Community Hospital (BRCH). Strategic and effective marketing efforts should target technologists, nurses, physicians (including radiologists), administration, and colleagues in other departments. The buy-in of these users is critical to the project's success. BRCH's first marketing effort took place during the initial PACS presentation made to the hospital's board of directors. Once approval was given and a 6-month implementation target was set, a strategic and effective marketing/education plan commenced. Posters, brochures, t-shirts, and promotional items were distributed in a coordinated effort to target hospital staff and referring physician offices. Through its "Got PACS?" branding and other identity materials, BRCH implemented a marketing plan that informed, educated, and engaged PACS users.

The Formation of Massive Stars: from Herschel to Near-Infrared

Directory of Open Access Journals (Sweden)

Paolo Persi

2014-12-01

Full Text Available We have studied a number of selected high mass star forming regions, including high resolution near-infrared broad- and narrow-band imaging, Herschel (70, 160, 250, 350 and 500 μm and Spitzer (3.6, 4.5, 5.8 and 8.0 m images. The preliminary results of one of this region, IRAS 19388+2357(MOL110 are discussed. In this region a dense core has been detected in the far-infrared, and a young stellar cluster has been found around this core. Combining near-IR data with Spitzer and Herschel photometry we have derived the spectral energy distribution of Mol110. Finally comparing our H2 and Kc narrow-band images, we have found an H2 jet in this region.

Molecular outflows driven by low-mass protostars. I. Correcting for underestimates when measuring outflow masses and dynamical properties

Energy Technology Data Exchange (ETDEWEB)

Dunham, Michael M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 78, Cambridge, MA 02138 (United States); Arce, Héctor G. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States); Mardones, Diego [Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile); Lee, Jeong-Eun [Department of Astronomy and Space Science, Kyung Hee University, Yongin, Gyeonggi 446-701 (Korea, Republic of); Matthews, Brenda C. [National Research Council of Canada, Herzberg Astronomy and Astrophysics, 5071 W. Saanich Road, Victoria, BC V9E 2E7 (Canada); Stutz, Amelia M. [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117, Heidelberg (Germany); Williams, Jonathan P., E-mail: mdunham@cfa.harvard.edu [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States)

2014-03-01

We present a survey of 28 molecular outflows driven by low-mass protostars, all of which are sufficiently isolated spatially and/or kinematically to fully separate into individual outflows. Using a combination of new and archival data from several single-dish telescopes, 17 outflows are mapped in {sup 12}CO (2-1) and 17 are mapped in {sup 12}CO (3-2), with 6 mapped in both transitions. For each outflow, we calculate and tabulate the mass (M {sub flow}), momentum (P {sub flow}), kinetic energy (E {sub flow}), mechanical luminosity (L {sub flow}), and force (F {sub flow}) assuming optically thin emission in LTE at an excitation temperature, T {sub ex}, of 50 K. We show that all of the calculated properties are underestimated when calculated under these assumptions. Taken together, the effects of opacity, outflow emission at low velocities confused with ambient cloud emission, and emission below the sensitivities of the observations increase outflow masses and dynamical properties by an order of magnitude, on average, and factors of 50-90 in the most extreme cases. Different (and non-uniform) excitation temperatures, inclination effects, and dissociation of molecular gas will all work to further increase outflow properties. Molecular outflows are thus almost certainly more massive and energetic than commonly reported. Additionally, outflow properties are lower, on average, by almost an order of magnitude when calculated from the {sup 12}CO (3-2) maps compared to the {sup 12}CO (2-1) maps, even after accounting for different opacities, map sensitivities, and possible excitation temperature variations. It has recently been argued in the literature that the {sup 12}CO (3-2) line is subthermally excited in outflows, and our results support this finding.

Outflow Kinematics Manifested by the Hα Line: Gas Outflows in Type 2 AGNs. IV

Energy Technology Data Exchange (ETDEWEB)

Kang, Daeun; Woo, Jong-Hak; Bae, Hyun-Jin, E-mail: woo@astro.snu.ac.kr [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of)

2017-08-20

Energetic ionized gas outflows driven by active galactic nuclei (AGNs) have been studied as a key phenomenon related to AGN feedback. To probe the kinematics of the gas in the narrow-line region, [O iii] λ 5007 has been utilized in a number of studies showing nonvirial kinematic properties due to AGN outflows. In this paper, we statistically investigate whether the H α emission line is influenced by AGN-driven outflows by measuring the kinematic properties based on the H α line profile and comparing them with those of [O iii]. Using the spatially integrated spectra of ∼37,000 Type 2 AGNs at z < 0.3 selected from the Sloan Digital Sky Survey DR7, we find a nonlinear correlation between H α velocity dispersion and stellar velocity dispersion that reveals the presence of the nongravitational component, especially for AGNs with a wing component in H α . The large H α velocity dispersion and velocity shift of luminous AGNs are clear evidence of AGN outflow impacts on hydrogen gas, while relatively smaller kinematic properties compared to those of [O iii] imply that the observed outflow effect on the H α line is weaker than the case of [O iii].

SUBMILLIMETER LINE SPECTRUM OF THE SEYFERT GALAXY NGC 1068 FROM THE HERSCHEL-SPIRE FOURIER TRANSFORM SPECTROMETER

International Nuclear Information System (INIS)

Spinoglio, Luigi; Pereira-Santaella, Miguel; Busquet, Gemma; Schirm, Maximilien R. P.; Wilson, Christine D.; Parkin, Tara J.; Glenn, Jason; Kamenetzky, Julia; Rangwala, Naseem; Maloney, Philip R.; Bendo, George J.; Madden, Suzanne C.; Wolfire, Mark G.; Boselli, Alessandro; Cooray, Asantha; Page, Mathew J.

2012-01-01

The first complete submillimeter spectrum (190-670 μm) of the Seyfert 2 galaxy NGC 1068 has been observed with the SPIRE Fourier transform spectrometer on board the Herschel Space Observatory. The sequence of CO lines (J up = 4-13), lines from H 2 O, the fundamental rotational transition of hydrogen fluoride, two o-H 2 O + lines, and one line each from CH + and OH + have been detected, together with the two [C I] lines and the [N II] 205 μm line. The observations in both single pointing mode with sparse image sampling and in mapping mode with full image sampling allow us to disentangle two molecular emission components, one due to the compact circumnuclear disk (CND) and one from the extended region encompassing the star-forming ring (SF-ring). Radiative transfer models show that the two CO components are characterized by densities of n(H 2 ) = 10 4.5 and 10 2.9 cm –3 and temperatures of T kin = 100 K and 127 K, respectively. A comparison of the CO line intensities with the photodissociation region (PDR) and X-ray-dominated region (XDR) models, together with the other observational constraints, such as the observed CO surface brightness and the radiation field, indicates that the best explanation for the CO excitation of the CND is an XDR with a density of n(H 2 ) ∼ 10 4 cm –3 and an X-ray flux of 9 erg s –1 cm –2 , consistent with illumination by the active galactic nucleus, while the CO lines in the SF-ring are better modeled by a PDR. The detected water transitions, together with those observed with the Herschel PACS spectrometer, can be modeled by a large velocity gradient model with low temperature (T kin ∼ 40 K) and high density (n(H 2 ) in the range 10 6.7 -10 7.9 cm –3 ). The emission of H 2 O + and OH + are in agreement with PDR models with cosmic-ray ionization. The diffuse ionized atomic component observed through the [N II] 205 μm line is consistent with previous photoionization models of the starburst.

HyPac french platform on the hydrogen and fuel cells; HyPac plateforme francaise sur l'hydrogene et les piles a combustible

Energy Technology Data Exchange (ETDEWEB)

Lucchese, P. [N ' ERGY, 85 - Antigny (France)

2008-07-01

HyPac is a french platform on the hydrogen and fuel cells applications, created in 2008. the authors presents the opportunities of the french platform HyPac, the objectives, the participants and the budget. (A.L.B.)

Large-Scale Outflows in Seyfert Galaxies

Science.gov (United States)

Colbert, E. J. M.; Baum, S. A.

1995-12-01

\\catcode`\\@=11 \\ialign{m @th#1hfil ##hfil \\crcr#2\\crcr\\sim\\crcr}}} \\catcode`\\@=12 Highly collimated outflows extend out to Mpc scales in many radio-loud active galaxies. In Seyfert galaxies, which are radio-quiet, the outflows extend out to kpc scales and do not appear to be as highly collimated. In order to study the nature of large-scale (>~1 kpc) outflows in Seyferts, we have conducted optical, radio and X-ray surveys of a distance-limited sample of 22 edge-on Seyfert galaxies. Results of the optical emission-line imaging and spectroscopic survey imply that large-scale outflows are present in >~{{1} /{4}} of all Seyferts. The radio (VLA) and X-ray (ROSAT) surveys show that large-scale radio and X-ray emission is present at about the same frequency. Kinetic luminosities of the outflows in Seyferts are comparable to those in starburst-driven superwinds. Large-scale radio sources in Seyferts appear diffuse, but do not resemble radio halos found in some edge-on starburst galaxies (e.g. M82). We discuss the feasibility of the outflows being powered by the active nucleus (e.g. a jet) or a circumnuclear starburst.

Removal of a synthetic organic chemical by PAC-UF systems. II: Model application.

Science.gov (United States)

Matsui, Y; Colas, F; Yuasa, A

2001-02-01

This paper describes several application potentials with a recently developed model for predicting the synthetic organic chemical (SOC) removal by powdered activated carbon (PAC) adsorption during ultrafiltration (UF) and discusses the removal mechanism. The model was successfully applied, without any modification, to dead-end mode operation as well as to cross-flow mode operation, validating the assumption of the internal diffusion control mechanism and the continuously-stirred-tank-reactor (CSTR) concept. Even when UF was operated in a cross-flow mode, PAC added was re-circulating in suspension for only a short time. Then, solute uptake took place mostly by PAC immobilized in membrane tubes not only for dead-end operation but also for cross-flow operation. Therefore, cross-flow operation did not have any advantage regarding the SOC mass transfer on PAC in UF loop over dead-end operation. The model simulation implied that pulse PAC addition at the beginning of filtration cycle resulted better SOC removal than continuous PAC addition. However, for the pulse PAC addition mode, the model predicted somewhat lower effluent SOC concentration than the observed values, and the benefit of pulse PAC application in terms of reducing SOC over its continuous dosage was not confirmed. Longer detention time of PAC dosed in a pulse than continuously dosed PAC could possibly further decrease internal diffusivity.

INVESTIGATING PARTICLE ACCELERATION IN PROTOSTELLAR JETS: THE TRIPLE RADIO CONTINUUM SOURCE IN SERPENS

Energy Technology Data Exchange (ETDEWEB)

Rodríguez-Kamenetzky, Adriana; Valotto, Carlos [Instituto de Astronomía Teórica y Experimental, (IATE-UNC), X5000BGR Córdoba (Argentina); Carrasco-González, Carlos; Rodríguez, Luis F. [Instituto de Radioastronomía y Astrofísica (IRyA-UNAM), 58089 Morelia, México (Mexico); Araudo, Anabella [University of Oxford, Astrophysics, Keble Road, Oxford OX1 3RH (United Kingdom); Torrelles, José M. [Institut de Ciències de l’Espai (CSIC-IEEC) and Institut de Ciències del Cosmos (UB-IEEC), Martí i Franquès 1, E-08028 Barcelona (Spain); Anglada, Guillem [Instituto de Astrofísica de Andalucía, CSIC, Camino Bajo de Huétor 50, E-18008 Granada (Spain); Martí, Josep [Dept. de Física, EPS de Jaén, Universidad de Jaén, Campus Las Lagunillas s/n, A3-402, E-23071 Jaén (Spain)

2016-02-10

While most protostellar jets present free–free emission at radio wavelengths, synchrotron emission has also been proposed to be present in a handful of these objects. The presence of nonthermal emission has been inferred by negative spectral indices at centimeter wavelengths. In one case (the HH 80-81 jet arising from a massive protostar), its synchrotron nature was confirmed by the detection of linearly polarized radio emission. One of the main consequences of these results is that synchrotron emission implies the presence of relativistic particles among the nonrelativistic material of these jets. Therefore, an acceleration mechanism should be taking place. The most probable scenario is that particles are accelerated when the jets strongly impact against the dense envelope surrounding the protostar. Here we present an analysis of radio observations obtained with the Very Large Array of the triple radio source in the Serpens star-forming region. This object is known to be a radio jet arising from an intermediate-mass protostar. It is also one of the first protostellar jets where the presence of nonthermal emission was proposed. We analyze the dynamics of the jet and the nature of the emission and discuss these issues in the context of the physical parameters of the jet and the particle acceleration phenomenon.

Evolutionistic or revolutionary paths? A PACS maturity model for strategic situational planning.

Science.gov (United States)

van de Wetering, Rogier; Batenburg, Ronald; Lederman, Reeva

2010-07-01

While many hospitals are re-evaluating their current Picture Archiving and Communication System (PACS), few have a mature strategy for PACS deployment. Furthermore, strategies for implementation, strategic and situational planning methods for the evolution of PACS maturity are scarce in the scientific literature. Consequently, in this paper we propose a strategic planning method for PACS deployment. This method builds upon a PACS maturity model (PMM), based on the elaboration of the strategic alignment concept and the maturity growth path concept previously developed in the PACS domain. First, we review the literature on strategic planning for information systems and information technology and PACS maturity. Secondly, the PMM is extended by applying four different strategic perspectives of the Strategic Alignment Framework whereupon two types of growth paths (evolutionistic and revolutionary) are applied that focus on a roadmap for PMM. This roadmap builds a path to get from one level of maturity and evolve to the next. An extended method for PACS strategic planning is developed. This method defines eight distinctive strategies for PACS strategic situational planning that allow decision-makers in hospitals to decide which approach best suits their hospitals' current situation and future ambition and what in principle is needed to evolve through the different maturity levels. The proposed method allows hospitals to strategically plan for PACS maturation. It is situational in that the required investments and activities depend on the alignment between the hospital strategy and the selected growth path. The inclusion of both strategic alignment and maturity growth path concepts make the planning method rigorous, and provide a framework for further empirical research and clinical practice.

LANSCE personnel access control system (PACS)

International Nuclear Information System (INIS)

Sturrock, J.C.; Gallegos, F.R.; Hall, M.J.

1997-01-01

The Radiation Security System (RSS) at the Los Alamos Neutron Science Center (LANSCE) provides personnel protection from prompt radiation due to accelerated beam. The Personnel Access Control System (PACS) is a component of the RSS that is designed to prevent personnel access to areas where prompt radiation is a hazard. PACS was designed to replace several older personnel safety systems (PSS) with a single modem unified design. Lessons learned from the operation over the last 20 years were incorporated into a redundant sensor, single-point failure safe, fault tolerant, and tamper-resistant system that prevents access to the beam areas by controlling the access keys and beam stoppers. PACS uses a layered philosophy to the physical and electronic design. The most critical assemblies are battery backed up, relay logic circuits; less critical devices use Programmable Logic Controllers (PLCs) for timing functions and communications. Outside reviewers have reviewed the operational safety of the design. The design philosophy, lessons learned, hardware design, software design, operation, and limitations of the device are described

Enabling Velocity-Resolved Science with Advanced Processing of Herschel/HIFI Observations

Science.gov (United States)

Morris, Patrick

an effort lead at the NASA Herschel Science Center, and delivered in November 2016 to the NASA InfraRed Science Archive (IRSA) and the HSA where they are available to the community. Due to limited resources, this effort could not cover the full list of observations in need of interactive treatments. We are proposing to cover that final set observations (spectral maps and a selection of spectral scans and point observations) in a project spread over 2 years with 0.5 FTE funding, for a guaranteed set of phased deliverables produced with optimized quality at high efficiency using expert processing and delivery procedures already in place. This effort will tackle the quality-degrading artifacts which could not be corrected in the automatic pipeline -- and becoming more and more remote for potential users to correct on their own even with scripted guidance. The expectation is that the huge investments by the funding agencies, and the successful operations of the observatory meeting and often exceeding performance requirements, can be returned to the maximum scientific extent possible. We can guarantee some of that scientific return, in a study of fundamental carbon chemistry in energetic star forming regions, using the proposed HPDPs from unpublished and partially unexploited HIFI data to probe UV- and shockdriven chemistries to explain an unexpected deficiency of C+ in the Orion KL eruptive outflow. We will test a hypothesis that C+ is depleted by production of CO rather than CH+, through a chain of reactions involving intermediate products suited to the molecular environment.

Measurement of Outflow Facility Using iPerfusion.

Directory of Open Access Journals (Sweden)

Joseph M Sherwood

Full Text Available Elevated intraocular pressure (IOP is the predominant risk factor for glaucoma, and reducing IOP is the only successful strategy to prevent further glaucomatous vision loss. IOP is determined by the balance between the rates of aqueous humour secretion and outflow, and a pathological reduction in the hydraulic conductance of outflow, known as outflow facility, is responsible for IOP elevation in glaucoma. Mouse models are often used to investigate the mechanisms controlling outflow facility, but the diminutive size of the mouse eye makes measurement of outflow technically challenging. In this study, we present a new approach to measure and analyse outflow facility using iPerfusion™, which incorporates an actuated pressure reservoir, thermal flow sensor, differential pressure measurement and an automated computerised interface. In enucleated eyes from C57BL/6J mice, the flow-pressure relationship is highly non-linear and is well represented by an empirical power law model that describes the pressure dependence of outflow facility. At zero pressure, the measured flow is indistinguishable from zero, confirming the absence of any significant pressure independent flow in enucleated eyes. Comparison with the commonly used 2-parameter linear outflow model reveals that inappropriate application of a linear fit to a non-linear flow-pressure relationship introduces considerable errors in the estimation of outflow facility and leads to the false impression of pressure-independent outflow. Data from a population of enucleated eyes from C57BL/6J mice show that outflow facility is best described by a lognormal distribution, with 6-fold variability between individuals, but with relatively tight correlation of facility between fellow eyes. iPerfusion represents a platform technology to accurately and robustly characterise the flow-pressure relationship in enucleated mouse eyes for the purpose of glaucoma research and with minor modifications, may be applied

Incremental cost of PACS in a medical intensive care unit

Science.gov (United States)

Langlotz, Curtis P.; Cleff, Bridget; Even-Shoshan, Orit; Bozzo, Mary T.; Redfern, Regina O.; Brikman, Inna; Seshadri, Sridhar B.; Horii, Steven C.; Kundel, Harold L.

1995-05-01

Our purpose is to determine the incremental costs (or savings) due to the introduction of picture archiving and communication systems (PACS) and computed radiology (CR) in a medical intensive care unit (MICU). Our economic analysis consists of three measurement methods. The first method is an assessment of the direct costs to the radiology department, implemented in a spreadsheet model. The second method consists of a series of brief observational studies to measure potential changes in personnel costs that might not be reflected in administrative claims. The third method (results not reported here) is a multivariate modeling technique which estimates the independent effect of PACS/CR on the cost of care (estimated from administrative claims data), while controlling for clinical case- mix variables. Our direct cost model shows no cost savings to the radiology department after the introduction of PACS in the medical intensive care unit. Savings in film supplies and film library personnel are offset by increases in capital equipment costs and PACS operation personnel. The results of observational studies to date demonstrate significant savings in clinician film-search time, but no significant change in technologist time or lost films. Our model suggests that direct radiology costs will increase after the limited introduction of PACS/CR in the MICU. Our observational studies show a small but significant effect on clinician film search time by the introduction of PACS/CR in the MICU, but no significant effect on other variables. The projected costs of a hospital-wide PACS are currently under study.

[Sewage sludge conditioning by bioleaching-dual PAC and PAM addition].

Science.gov (United States)

Liu, Chang-Geng; Zhang, Pan-Yue; Zeng, Guang-Ming; Liu, Yong-Gang

2010-09-01

Bioleaching-dual polyaluminum chloride (PAC) and polyacrylamide (PAM) addition was used to condition sewage sludge. The results showed that FeSO4 x 7H2O addition improved the bioleaching rate obviously with a fixed sulfur power dosage of 3 g x L(-1); when the FeSO4 x 7H2O dosage was 8 g x L(-1), the bioleaching lasted 1.5 d to decrease the sludge pH below 2. Bioleaching improved the sludge dewaterability significantly with a specific resistance to filtration (SRF) reduction of 77.52% from 6.45 x 10(10)s2 x g(-10 to 1.45 x 10(10)s2 x g(-1), but the bioleached sludge was still difficult to be dewatered. After adjusting the bioleached sludge pH to 6, PAC and PAM were used to enhance conditioning of the bioleached sludge. The results indicated that the optimal dosage was 200 mg x L(-1) for PAC or 50 mg x L(-1) for PAM when single chemical was used. When PAC and PAM were dually used, the optimal dosages of PAC and PAM were 100 mg x L(-1) and 25 mg x L(-1), respectively; SRF and moisture of sludge cake reduced to 2.02 x 10(8) s2 x g(-1) and 74.81%, respectively, showing good dewaterability of the treated sludge. Compared with the single use of PAC and PAM, the dual use of PAC and PAM showed the advantages of lower cost and better conditioning effect.

La inserción al Asia-Pacífico, oportunidades y desafíos para el Valle del Cauca y la región pacífica colombiana

Directory of Open Access Journals (Sweden)

Ricardo Coutin

2014-12-01

Full Text Available Resumen: El objetivo general del texto es brindar una aproximación a los retos y las oportunidades que representa, para el Valle del Cauca y la Región Pacífica colombiana, la inserción al Asia-Pacífico. Para lo cual se plantean tres objetivos específicos: primero, analizar someramente el contexto económico comercial del Asia-Pacífico y América Latina, con especial énfasis en Colombia y los demás países de la Alianza del Pacífico (AP; segundo, estudiar las oportunidades y los retos para el Valle del Cauca y la Región Pacífica colombiana que plantea la puesta en escena del bloque comercial denominado Alianza del Pacífico; y tercero, indagar sobre los retos de competitividad y productividad que enfrenta el Valle del Cauca y que afectan el ambiente de negocios. El documento concluye que Colombia se encuentra rezagada en su inserción con la cuenca del Asia-Pacífico; también se plantea la necesidad de abordar el tema de estudio desde un enfoque subnacional.

GALAXY OUTFLOWS WITHOUT SUPERNOVAE

Energy Technology Data Exchange (ETDEWEB)

Sur, Sharanya [Indian Institute of Astrophysics, 2nd Block, Koramangala, Bangalore 560034 (India); Scannapieco, Evan [School of Earth and Space Exploration, Arizona State University, P.O. Box 876004, Tempe-85287 (United States); Ostriker, Eve C., E-mail: sharanya.sur@iiap.res.in, E-mail: sharanya.sur@asu.edu [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

2016-02-10

High surface density, rapidly star-forming galaxies are observed to have ≈50–100 km s{sup −1} line of sight velocity dispersions, which are much higher than expected from supernova driving alone, but may arise from large-scale gravitational instabilities. Using three-dimensional simulations of local regions of the interstellar medium, we explore the impact of high velocity dispersions that arise from these disk instabilities. Parametrizing disks by their surface densities and epicyclic frequencies, we conduct a series of simulations that probe a broad range of conditions. Turbulence is driven purely horizontally and on large scales, neglecting any energy input from supernovae. We find that such motions lead to strong global outflows in the highly compact disks that were common at high redshifts, but weak or negligible mass loss in the more diffuse disks that are prevalent today. Substantial outflows are generated if the one-dimensional horizontal velocity dispersion exceeds ≈35 km s{sup −1}, as occurs in the dense disks that have star-formation rate (SFR) densities above ≈0.1 M{sub ⊙} yr{sup −1} kpc{sup −2}. These outflows are triggered by a thermal runaway, arising from the inefficient cooling of hot material coupled with successive heating from turbulent driving. Thus, even in the absence of stellar feedback, a critical value of the SFR density for outflow generation can arise due to a turbulent heating instability. This suggests that in strongly self-gravitating disks, outflows may be enhanced by, but need not caused by, energy input from supernovae.

The ALMA Protostellar Interferometric Line Survey (PILS). First results from an unbiased submillimeter wavelength line survey of the Class 0 protostellar binary IRAS 16293-2422 with ALMA

Science.gov (United States)

Jørgensen, J. K.; van der Wiel, M. H. D.; Coutens, A.; Lykke, J. M.; Müller, H. S. P.; van Dishoeck, E. F.; Calcutt, H.; Bjerkeli, P.; Bourke, T. L.; Drozdovskaya, M. N.; Favre, C.; Fayolle, E. C.; Garrod, R. T.; Jacobsen, S. K.; Öberg, K. I.; Persson, M. V.; Wampfler, S. F.

2016-11-01

Context. The inner regions of the envelopes surrounding young protostars are characterized by a complex chemistry, with prebiotic molecules present on the scales where protoplanetary disks eventually may form. The Atacama Large Millimeter/submillimeter Array (ALMA) provides an unprecedented view of these regions zooming in on solar system scales of nearby protostars and mapping the emission from rare species. Aims: The goal is to introduce a systematic survey, the Protostellar Interferometric Line Survey (PILS), of the chemical complexity of one of the nearby astrochemical templates, the Class 0 protostellar binary IRAS 16293-2422, using ALMA in order to understand the origin of the complex molecules formed in its vicinity. In addition to presenting the overall survey, the analysis in this paper focuses on new results for the prebiotic molecule glycolaldehyde, its isomers, and rarer isotopologues and other related molecules. Methods: An unbiased spectral survey of IRAS 16293-2422 covering the full frequency range from 329 to 363 GHz (0.8 mm) has been obtained with ALMA, in addition to a few targeted observations at 3.0 and 1.3 mm. The data consist of full maps of the protostellar binary system with an angular resolution of 0.5'' (60 AU diameter), a spectral resolution of 0.2 km s-1, and a sensitivity of 4-5 mJy beam-1 km s-1, which is approximately two orders of magnitude better than any previous studies. Results: More than 10 000 features are detected toward one component in the protostellar binary, corresponding to an average line density of approximately one line per 3 km s-1. Glycolaldehyde; its isomers, methyl formate and acetic acid; and its reduced alcohol, ethylene glycol, are clearly detected and their emission well-modeled with an excitation temperature of 300 K. For ethylene glycol both lowest state conformers, aGg' and gGg', are detected, the latter for the first time in the interstellar medium (ISM). The abundance of glycolaldehyde is comparable to or

A PACS archive architecture supported on cloud services.

Science.gov (United States)

Silva, Luís A Bastião; Costa, Carlos; Oliveira, José Luis

2012-05-01

Diagnostic imaging procedures have continuously increased over the last decade and this trend may continue in coming years, creating a great impact on storage and retrieval capabilities of current PACS. Moreover, many smaller centers do not have financial resources or requirements that justify the acquisition of a traditional infrastructure. Alternative solutions, such as cloud computing, may help address this emerging need. A tremendous amount of ubiquitous computational power, such as that provided by Google and Amazon, are used every day as a normal commodity. Taking advantage of this new paradigm, an architecture for a Cloud-based PACS archive that provides data privacy, integrity, and availability is proposed. The solution is independent from the cloud provider and the core modules were successfully instantiated in examples of two cloud computing providers. Operational metrics for several medical imaging modalities were tabulated and compared for Google Storage, Amazon S3, and LAN PACS. A PACS-as-a-Service archive that provides storage of medical studies using the Cloud was developed. The results show that the solution is robust and that it is possible to store, query, and retrieve all desired studies in a similar way as in a local PACS approach. Cloud computing is an emerging solution that promises high scalability of infrastructures, software, and applications, according to a "pay-as-you-go" business model. The presented architecture uses the cloud to setup medical data repositories and can have a significant impact on healthcare institutions by reducing IT infrastructures.

Java-based cryptosystem for PACS and tele-imaging

Science.gov (United States)

Tjandra, Donny; Wong, Stephen T. C.; Yu, Yuan-Pin

1998-07-01

Traditional PACS systems are based on two-tier client server architectures, and require the use of costly, high-end client workstations for image viewing. Consequently, PACS systems using the two-tier architecture do not scale well as data increases in size and complexity. Furthermore, use of dedicated viewing workstations incurs costs in deployment and maintenance. To address these issues, the use of digital library technologies, such as the World Wide Web, Java, and CORBA, is being explored to distribute PACS data to serve a broader range of healthcare providers in an economic and efficient manner. Integration of PACS systems with digital library technologies allows access to medical information through open networks such as the Internet. However, use of open networks to transmit medical data introduces problems with maintaining privacy and integrity of patient information. Cryptography and digital timestamping is used to protect sensitive information from unauthorized access or tampering. A major concern when using cryptography and digital timestamping is the performance degradation associated with the mathematical calculations needed to encrypt/decrypt an image dataset, or to calculate the hash value of an image. The performance issue is compounded by the extra layer associated with the CORBA middleware, and the use of programming languages interpreted at the client side, such as Java. This paper study the extent to which Java-based cryptography and digital timestamping affects performance in a PACS system integrated with digital library technologies.

REVIEW ARTICLE REVI REVI Talking PACS: Part 1 – What is PACS?

African Journals Online (AJOL)

Image management is the administration of imaging examination requests, the performance of ... responsibility dependent on a long chain of human interaction that often fails. Within both ... This is an information system responsible for the storage, distribution .... This refers to a computer interface to gain access to the PACS.

OH outflows in star-forming regions

International Nuclear Information System (INIS)

Mirabel, I.F.; Ruiz, A.; Rodriguez, L.F.; Canto, J.; Universidad de Puer; Universidad de Puerto Rico, Rio Piedras; Universidad Nacional Autonoma de Mexico, Mexico City)

1987-01-01

The results from a survey for high-velocity OH in molecular outflows in star-forming regions are reported. High-velocity OH was detected in absorption in nine of these regions. When the telescope beam can resolve the outflows, they show similar anisotropic angular distribution as the redshifted and blueshifted CO. The OH transitions are markedly subthermal since for several sources it is found that the radiation that is being absorbed is a background continuum constituted by the cosmic component plus a small Galactic contribution. The absorbing OH appears to trace gas with higher velocities and lower densities than does the CO and, in some cases, provides information on the structure of the outflows at larger distances from the central source. At scales of 0.1 pc, the outflows are elongated in the direction of the steepest density gradient of the ambient cloud, suggesting that the large-scale collimation of the outflow is produced by the density structure of the ambient cloud. 29 references

Partners Against Crime (PAC) Districts

Data.gov (United States)

City and County of Durham, North Carolina — The Partners Against Crime (PAC) program promotes collaboration among police officers, Durham residents, and city and county government officials to find...

WIND-DRIVEN ACCRETION IN TRANSITIONAL PROTOSTELLAR DISKS

Energy Technology Data Exchange (ETDEWEB)

Wang, Lile; Goodman, Jeremy J. [Princeton University Observatory, Princeton, NJ 08544 (United States)

2017-01-20

Transitional protostellar disks have inner cavities that are heavily depleted in dust and gas, yet most of them show signs of ongoing accretion, often at rates comparable to full disks. We show that recent constraints on the gas surface density in a few well-studied disk cavities suggest that the accretion speed is at least transsonic. We propose that this is the natural result of accretion driven by magnetized winds. Typical physical conditions of the gas inside these cavities are estimated for plausible X-ray and FUV radiation fields. The gas near the midplane is molecular and predominantly neutral, with a dimensionless ambipolar parameter in the right general range for wind solutions of the type developed by Königl, Wardle, and others. That is to say, the density of ions and electrons is sufficient for moderately good coupling to the magnetic field, but it is not so good that the magnetic flux needs to be dragged inward by the accreting neutrals.

Strengthening your ties to referring physicians through RIS/PACS integration.

Science.gov (United States)

Worthy, Susan; Rounds, Karla C; Soloway, Connie B

2003-01-01

Many imaging centers are turning to technology solutions to increase refering physician satisfaction, implementing such enhancements as automated report distribution, picture archiving and communications system (PACS), radiology information systems (RIS), and web-based results access. However, without seamless integration, these technology investments don't address the challenge at its core: convenient and reliable, two-way communication and interaction with referring physicians. In an integrated RIS/PACS solution, patient tracking in the RIS and PACS study status are logged and available to users. The time of the patient's registration at the imaging center, the exam start and completion time, the patient's departure time from the imaging center, and results status are all tracked and logged. An integrated RIS/PACS solution provides additional support to the radiologist, a critical factor that can improve the turnaround time of results to referring physicians. The RIS/PACS enhances the interpretation by providing the patient's history, which gives the radiologist additional insight and decreases the likelihood of missing a diagnostic element. In a tightly integrated RIS/PACS solution, results information is more complete. Physicians can view reports with associated images selected by the radiologist. They will also have full order information and complete imaging history including prior reports and images. Referring physicians can access and view images and exam notes at the same time that the radiologist is interpreting the exam. Without the benefit of an integrated RIS/PACS system, the referring physician would have to wait for the signed transcription to be released. In a seamlessly integrated solution, film-tracking modules within the RIS are fused with digital imaging workflow in the PACS. Users can see at a glance if a historical exam is available on film and benefit when a complete study history--both film-based and digital--is presented with the current

Performance characteristics of the Mayo/IBM PACS

Science.gov (United States)

Persons, Kenneth R.; Gehring, Dale G.; Pavicic, Mark J.; Ding, Yingjai

1991-07-01

The Mayo Clinic and IBM (at Rochester, Minnesota) have jointly developed a picture archiving system for use with Mayo's MRI and Neuro CT imaging modalities. The communications backbone of the PACS is a portion of the Mayo institutional network: a series of 4-Mbps token rings interconnected by bridges and fiber optic extensions. The performance characteristics of this system are important to understand because they affect the response time a PACS user can expect, and the response time for non-PACS users competing for resources on the institutional network. The performance characteristics of each component and the average load levels of the network were measured for various load distributions. These data were used to quantify the response characteristics of the existing system and to tune a model developed by North Dakota State University Department of Computer Science for predicting response times of more complex topologies.

Far-infrared photometry of OJ 287 with the Herschel Space Observatory

Science.gov (United States)

Kidger, Mark; Zola, Staszek; Valtonen, Mauri; Lähteenmäki, Anne; Järvelä, Emilia; Tornikoski, Merja; Tammi, Joni; Liakos, Alexis; Poyner, Gary

2018-03-01

Context. The blazar OJ 287 has shown a ≈12 year quasi-periodicity over more than a century, in addition to the common properties of violent variability in all frequency ranges. It is the strongest known candidate to have a binary singularity in its central engine. Aim. We aim to better understand the different emission components by searching for correlated variability in the flux over four decades of frequency measurements. Methods: We combined data at frequencies from the millimetric to the visible to characterise the multifrequency light curve in April and May 2010. This includes the only photometric observations of OJ 287 made with the Herschel Space Observatory: five epochs of data obtained over 33 days at 250, 350, and 500 μm with Herschel-SPIRE. Results: Although we find that the variability at 37 GHz on timescales of a few weeks correlates with the visible to near-IR spectral energy distribution, there is a small degree of reddening in the continuum at lower flux levels that is revealed by the decreasing rate of decline in the light curve at lower frequencies. However, we see no clear evidence that a rapid flare detected in the light curve during our monitoring in the visible to near-IR light curve is seen either in the Herschel data or at 37 GHz, suggesting a low-frequency cut-off in the spectrum of such flares. Conclusions.We see only marginal evidence of variability in the observations with Herschel over a month, although this may be principally due to the poor sampling. The spectral energy distribution between 37 GHz and the visible can be characterised by two components of approximately constant spectral index: a visible to far-IR component of spectral index α = -0.95, and a far-IR to millimetric spectral index of α = -0.43. There is no evidence of an excess of emission that would be consistent with the 60 μmdust bump found in many active galactic nuclei. Herschel is an ESA space observatory with science instruments provided by European

The physical characteristics of the gas in the disk of Centaurus a using the Herschel space observatory

Energy Technology Data Exchange (ETDEWEB)

Parkin, T. J.; Wilson, C. D.; Schirm, M. R. P. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1 (Canada); Baes, M.; De Looze, I. [Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281 S9, B-9000 Gent (Belgium); Boquien, M.; Boselli, A. [Laboratoire d' Astrophysique de Marseille, Université d' Aix-Marseille and CNRS, UMR7326, F-13388 Marseille Cedex 13 (France); Cormier, D. [Institut für theoretische Astrophysik, Zentrum für Astronomie der Universität Heidelberg, Albert-Ueberle Str. 2, D-69120 Heidelberg (Germany); Galametz, M. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA (United Kingdom); Karczewski, O. Ł. [Department of Physics and Astronomy, University of Sussex, Brighton, BN1 9QH (United Kingdom); Lebouteiller, V.; Madden, S. C. [CEA, Laboratoire AIM, Université Paris VII, IRFU/Service d' Astrophysique, Bat. 709, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Roussel, H. [Institut d' Astrophysique de Paris, UMR7095 CNRS, Université Pierre and Marie Curie, 98 bis Boulevard Arago, F-75014 Paris (France); Smith, M. W. L. [School of Physics and Astronomy, Cardiff University, The Parade, Cardiff CF24 3AA (United Kingdom); Spinoglio, L., E-mail: parkintj@mcmaster.ca [Istituto di Astrofisica e Planetologia Spaziali, INAF-IAPS, Via Fosso del Cavaliere 100, I-00133 Roma (Italy)

2014-05-20

We search for variations in the disk of Centaurus A of the emission from atomic fine structure lines using Herschel PACS and SPIRE spectroscopy. In particular, we observe the [C II](158 μm), [N II](122 and 205 μm), [O I](63 and 145 μm), and [O III](88 μm) lines, which all play an important role in cooling the gas in photo-ionized and photodissociation regions (PDRs). We determine that the ([C II]+[O I]{sub 63})/F {sub TIR} line ratio, a proxy for the heating efficiency of the gas, shows no significant radial trend across the observed region, in contrast to observations of other nearby galaxies. We determine that 10%-20% of the observed [C II] emission originates in ionized gas. Comparison between our observations and a PDR model shows that the strength of the far-ultraviolet radiation field, G {sub 0}, varies between 10{sup 1.75} and 10{sup 2.75} and the hydrogen nucleus density varies between 10{sup 2.75} and 10{sup 3.75} cm{sup –3}, with no significant radial trend in either property. In the context of the emission line properties of the grand-design spiral galaxy M51 and the elliptical galaxy NGC 4125, the gas in Cen A appears more characteristic of that in typical disk galaxies rather than elliptical galaxies.

Signatures of Young Planets in the Continuum Emission from Protostellar Disks

Science.gov (United States)

Isella, Andrea; Turner, Neal J.

2018-06-01

Many protostellar disks show central cavities, rings, or spiral arms likely caused by low-mass stellar or planetary companions, yet few such features are conclusively tied to bodies embedded in the disks. We note that even small features on the disk surface cast shadows, because the starlight grazes the surface. We therefore focus on accurately computing the disk thickness, which depends on its temperature. We present models with temperatures set by the balance between starlight heating and radiative cooling, which are also in vertical hydrostatic equilibrium. The planet has 20, 100, or 1000 M ⊕, ranging from barely enough to perturb the disk significantly, to clearing a deep tidal gap. The hydrostatic balance strikingly alters the appearance of the model disk. The outer walls of the planet-carved gap puff up under starlight heating, throwing a shadow across the disk beyond. The shadow appears in scattered light as a dark ring that could be mistaken for a gap opened by another more distant planet. The surface brightness contrast between outer wall and shadow for the 1000 M ⊕ planet is an order of magnitude greater than a model neglecting the temperature disturbances. The shadow is so deep that it largely hides the planet-launched outer arm of the spiral wave. Temperature gradients are such that outer low-mass planets undergoing orbital migration will converge within the shadow. Furthermore, the temperature perturbations affect the shape, size, and contrast of features at millimeter and centimeter wavelengths. Thus radiative heating and cooling are key to the appearance of protostellar disks with embedded planets.

Thermal/vacuum measurements of the Herschel space telescope by close-range photogrammetry

Science.gov (United States)

Parian, J. Amiri; Cozzani, A.; Appolloni, M.; Casarosa, G.

2017-11-01

In the frame of the development of a videogrammetric system to be used in thermal vacuum chambers at the European Space Research and Technology Centre (ESTEC) and other sites across Europe, the design of a network using micro-cameras was specified by the European Space agency (ESA)-ESTEC. The selected test set-up is the photogrammetric test of the Herschel Satellite Flight Model in the ESTEC Large Space Simulator. The photogrammetric system will be used to verify the Herschel Telescope alignment and Telescope positioning with respect to the Cryostat Vacuum Vessel (CVV) inside the Large Space Simulator during Thermal-Vacuum/Thermal-Balance test phases. We designed a close-range photogrammetric network by heuristic simulation and a videogrammetric system with an overall accuracy of 1:100,000. A semi-automated image acquisition system, which is able to work at low temperatures (-170°C) in order to acquire images according to the designed network has been constructed by ESA-ESTEC. In this paper we will present the videogrammetric system and sub-systems and the results of real measurements with a representative setup similar to the set-up of Herschel spacecraft which was realized in ESTEC Test Centre.

Sizing a PACS

Science.gov (United States)

Wilson, Dennis L.; Glicksman, Robert A.

1994-05-01

A Picture Archiving and Communications System (PACS) must be able to support the image rate of the medical treatment facility. In addition the PACS must have adequate working storage and archive storage capacity required. The calculation of the number of images per minute and the capacity of working storage and of archiving storage is discussed. The calculation takes into account the distribution of images over the different size of radiological images, the distribution between inpatient and outpatient, and the distribution over plain film CR images and other modality images. The support of the indirect clinical image load is difficult to estimate and is considered in some detail. The result of the exercise for a particular hospital is an estimate of the average size of the images and exams on the system, of the number of gigabytes of working storage, of the number of images moved per minute, of the size of the archive in gigabytes, and of the number of images that are to be moved by the archive per minute. The types of storage required to support the image rates and the capacity required are discussed.

Altered Circadian Food Anticipatory Activity Rhythms in PACAP Receptor 1 (PAC1 Deficient Mice.

Directory of Open Access Journals (Sweden)

Jens Hannibal

Full Text Available Light signals from intrinsically photosensitive retinal ganglion cells (ipRGCs entrain the circadian clock and regulate negative masking. Two neurotransmitters, glutamate and Pituitary Adenylate Cyclase Activating Polypeptide (PACAP, found in the ipRGCs transmit light signals to the brain via glutamate receptors and the specific PACAP type 1 (PAC1 receptor. Light entrainment occurs during the twilight zones and has little effect on clock phase during daytime. When nocturnal animals have access to food only for a few hours during the resting phase at daytime, they adapt behavior to the restricted feeding (RF paradigm and show food anticipatory activity (FAA. A recent study in mice and rats demonstrating that light regulates FAA prompted us to investigate the role of PACAP/PAC1 signaling in the light mediated regulation of FAA. PAC1 receptor knock out (PAC1-/- and wild type (PAC1+/+ mice placed in running wheels were examined in a full photoperiod (FPP of 12:12 h light/dark (LD and a skeleton photoperiod (SPP 1:11:1:11 h L:DD:L:DD at 300 and 10 lux light intensity. Both PAC1-/- mice and PAC1+/+ littermates entrained to FPP and SPP at both light intensities. However, when placed in RF with access to food for 4-5 h during the subjective day, a significant change in behavior was observed in PAC1-/- mice compared to PAC1+/+ mice. While PAC1-/- mice showed similar FAA as PAC1+/+ animals in FPP at 300 lux, PAC1-/- mice demonstrated an advanced onset of FAA with a nearly 3-fold increase in amplitude compared to PAC1+/+ mice when placed in SPP at 300 lux. The same pattern of FAA was observed at 10 lux during both FPP and SPP. The present study indicates a role of PACAP/PAC1 signaling during light regulated FAA. Most likely, PACAP found in ipRGCs mediating non-image forming light information to the brain is involved.

Protostellar formation in rotating interstellar clouds. I. Numerical methods and tests

International Nuclear Information System (INIS)

Boss, A.P.

1980-01-01

The details of how dense interstellar clouds collapse to form protostars are obscured from observation by the very clouds in which the condensation takes place, leaving an observational gap between the clouds and pre--main-sequence (PMS) stars. There is also a gap of roughly four orders of magnitude between the specific spin angular momentum of such clouds and that of PMS stars. Thus in order to fully understand the sequence of events in stellar formation, we must construct theoretical models of the collapse and fragmentation of rotating interstellar clouds into single or multiple protostellar systems

PAC Experiments at ISOLDE

CERN Multimedia

2002-01-01

The study of hyperfine interactions offers the possibility to use radioactive nuclei as probes in matter. The @g-@g perturbated angular correlation (PAC) technique following implantation has found widespread application in this field. At ISOLDE we have been investigating electric field gradients at impurities in non-cubic metals in an ongoing series of experiments. \\\\ \\\\ The small number of probe atoms necessary for these measurements make them also ideally suited for studies of surface problems like diffusion, structure and dynamics. Cd on a molybdenum O110? surface will be studied as first system. For this purpose 10|1|0~atoms of |1|1|1|mCd will be evaporated onto the clean surface and the electric field gradient for isolated adatoms on terrace sites will be determined by PAC. The UHV system constructed for such experiments at ISOLDE is shown in the schematic drawing. It is coupled to the beam line through differential pumping stations and contains standard surface treatment and analysis equipment.

PACS-Based Computer-Aided Detection and Diagnosis

Science.gov (United States)

Huang, H. K. (Bernie); Liu, Brent J.; Le, Anh HongTu; Documet, Jorge

The ultimate goal of Picture Archiving and Communication System (PACS)-based Computer-Aided Detection and Diagnosis (CAD) is to integrate CAD results into daily clinical practice so that it becomes a second reader to aid the radiologist's diagnosis. Integration of CAD and Hospital Information System (HIS), Radiology Information System (RIS) or PACS requires certain basic ingredients from Health Level 7 (HL7) standard for textual data, Digital Imaging and Communications in Medicine (DICOM) standard for images, and Integrating the Healthcare Enterprise (IHE) workflow profiles in order to comply with the Health Insurance Portability and Accountability Act (HIPAA) requirements to be a healthcare information system. Among the DICOM standards and IHE workflow profiles, DICOM Structured Reporting (DICOM-SR); and IHE Key Image Note (KIN), Simple Image and Numeric Report (SINR) and Post-processing Work Flow (PWF) are utilized in CAD-HIS/RIS/PACS integration. These topics with examples are presented in this chapter.

The energetics of AGN radiation pressure-driven outflows

Science.gov (United States)

Ishibashi, W.; Fabian, A. C.; Maiolino, R.

2018-05-01

The increasing observational evidence of galactic outflows is considered as a sign of active galactic nucleus (AGN) feedback in action. However, the physical mechanism responsible for driving the observed outflows remains unclear, and whether it is due to momentum, energy, or radiation is still a matter of debate. The observed outflow energetics, in particular the large measured values of the momentum ratio (\\dot{p}/(L/c) ˜ 10) and energy ratio (\\dot{E}_k/L ˜ 0.05), seems to favour the energy-driving mechanism; and most observational works have focused their comparison with wind energy-driven models. Here, we show that AGN radiation pressure on dust can adequately reproduce the observed outflow energetics (mass outflow rate, momentum flux, and kinetic power), as well as the scalings with luminosity, provided that the effects of radiation trapping are properly taken into account. In particular, we predict a sublinear scaling for the mass outflow rate (\\dot{M} ∝ L^{1/2}) and a superlinear scaling for the kinetic power (\\dot{E}_k ∝ L^{3/2}), in agreement with the observational scaling relations reported in the most recent compilation of AGN outflow data. We conclude that AGN radiative feedback can account for the global outflow energetics, at least equally well as the wind energy-driving mechanism, and therefore both physical models should be considered in the interpretation of future AGN outflow observations.

HyPac french platform on the hydrogen and fuel cells

International Nuclear Information System (INIS)

Lucchese, P.

2008-01-01

HyPac is a french platform on the hydrogen and fuel cells applications, created in 2008. the authors presents the opportunities of the french platform HyPac, the objectives, the participants and the budget. (A.L.B.)

PACS: Do clinical users benefit from it as a training adjunct?

Directory of Open Access Journals (Sweden)

J van Heerden

2011-05-01

Full Text Available Background. Over the past four years, Steve Biko Academic Hospital has been in the process of implementing and refining the use of a picture archiving and communications system (PACS. As part of a post-implementation refining process, it is necessary to evaluate user-perceptions in order to improve on good system qualities and correct flaws. Aim. The aim of this study was to assess whether medical clinicians perceived PACS as a positive adjunct to training and teaching opportunities – specifically those opportunities related to radiological image viewing and interpretation as part of patient case discussions. Method. Standardised questionnaires with ‘free text’ and ‘option selection’ questions were distributed to clinicians who, as part of their training, rotated at Steve Biko Academic Hospital (where a PACS is in place as well as other teaching hospitals without a PACS. Between February 2009 and May 2009, approximately 400 questionnaires were distributed. As a result of constant academic rotations, leave schedules of medical staff and posts vacated, questionnaires could not be distributed to the entire target population that was estimated to be in the region of 550 medical clinicians (comprising senior medical students, interns, medical officers, registrars and consultants. Of the 400 questionnaires distributed, 189 completed questionnaires were returned. Completion of the questionnaires was voluntary and anonymous. Results and conclusion. Although a PACS relates specifically to the archiving and retrieval of radiological images and reports, it became clear from the feedback received from medical clinicians (who are ward-based, theatre-based or clinic-based users of a digital system that many other factors, such as lack of adequate hardware and sub-optimal personal IT proficiency, contributed to some of the negative PACS-related perceptions and ‘lost teaching opportunities’ reported. Negative comments specifically related to PACS

The management and realizing of image data flow in PACS

International Nuclear Information System (INIS)

Tao Yonghao; Miao Jingtao

2002-01-01

Objective: To explore the management model and realizing of PACS image data-flow. Methods: Based on the implementing environment and management model of PACS image data-flow after full digital reengineering for radiology department in Shanghai First Hospital was completed, analysis on image data flow types, procedure, and achieving pattern were conducted. Results: Two kinds of image data-flow management were set up for the PACS of Shanghai First Hospital, which included image archiving procedure and image forward procedure. The former was implemented with central management model while the latter was achieved with a program that functionally acted as workflow management running on the central server. Conclusion: The image data-flow management pattern, as a key factor for PACS, has to be designed and implemented functionally and effectively depending on the performance environment, the tasks and requirements specified to particular user

A New Look at Speeding Outflows

Science.gov (United States)

Kohler, Susanna

2018-02-01

The compact centers of active galaxies known as active galactic nuclei, or AGN are known for the dynamic behavior they exhibit as the supermassive black holes at their centers accrete matter. New observations of outflows from a nearby AGN provide a more detailed look at what happens in these extreme environments.Outflows from GiantsThe powerful radio jets of Cygnus A, which extend far beyond the galaxy. [NRAO/AUI]AGN consist of a supermassive black hole of millions to tens of billions of solar masses surrounded by an accretion disk of in-falling matter. But not all the material falling toward the black hole accretes! Some of it is flung from the AGN via various types of outflows.The most well-known of these outflows are powerful radio jets collimated and incredibly fast-moving streams of particles that blast their way out of the host galaxy and into space. Only around 10% of AGN are observed to host such jets, however and theres another outflow thats more ubiquitous.Fast-Moving AbsorbersPerhaps 30% of AGN both those with and without observed radio jets host wider-angle, highly ionized gaseous outflows known as ultra-fast outflows (UFOs). Ultraviolet and X-ray radiation emitted from the AGN is absorbed by the UFO, revealing the outflows presence: absorption lines appear in the ultraviolet and X-ray spectra of the AGN, blue-shifted due to the high speeds of the absorbing gas in the outflow.Quasar PG 1211+143, indicated by the crosshairs at the center of the image, in the color context of its surroundings. [SDSS/S. Karge]But what is the nature of UFOs? Are they disk winds? Or are they somehow related to the radio jets? And what impact do they have on the AGNs host galaxy?X-ray and Ultraviolet CooperationNew observations are now providing fresh information about one particular UFO. A team of scientists led by Ashkbiz Danehkar (Harvard-Smithsonian Center for Astrophysics) recently used the Chandra and Hubble space telescopes to make the first simultaneous observations

A DICOM based PACS for nuclear medicine

International Nuclear Information System (INIS)

Lassmann, M.; Reiners, C.

2002-01-01

The installation of a radiology information system (RIS) connected to a hospital information system (HIS) and a picture archiving and communications system (PACS) seems mandatory for a nuclear medicine department in order to guarantee a high patient throughput. With these systems a fast transmission of reports, images to the in- and out-patients' wards and private practitioners is realized. Therefore, since April 2000, at the department of nuclear medicine of the university of Wuerzburg a completely DICOM based PACS has been implemented in addition to the RIS. With this system a DICOM based workflow is realized throughout the department of nuclear medicine for reporting and archiving. The PACS is connected to six gamma-cameras, a PET scanner, a bone densitometry system and an ultrasound device. The volume of image data archived per month is 4 GByte. Patient demographics are provided to the modalities via DICOM-Worklist. With these PACS components a department specific archive purely based on DICOM can be realized. During the installation process problems occurred mainly because of the complex DICOM standard for nuclear medicine. Related to that is the problem that most of the software implementations still contain bugs or are not adapted to the needs of a nuclear medicine department (particularly for PET). A communication software for the distribution of nuclear medicine reports and images based on techniques used for the worldwide web is currently tested. (orig.) [de

AGN outflows as neutrino sources: an observational test

Science.gov (United States)

Padovani, P.; Turcati, A.; Resconi, E.

2018-04-01

We test the recently proposed idea that outflows associated with Active Galactic Nuclei (AGN) could be neutrino emitters in two complementary ways. First, we cross-correlate a list of 94 "bona fide" AGN outflows with the most complete and updated repository of IceCube neutrinos currently publicly available, assembled by us for this purpose. It turns out that AGN with outflows matched to an IceCube neutrino have outflow and kinetic energy rates, and bolometric powers larger than those of AGN with outflows not matched to neutrinos. Second, we carry out a statistical analysis on a catalogue of [O III] λ5007 line profiles using a sample of 23,264 AGN at z values (˜6 and 18 per cent respectively, pre-trial) for relatively high velocities and luminosities. Our results are consistent with a scenario where AGN outflows are neutrino emitters but at present do not provide a significant signal. This can be tested with better statistics and source stacking. A predominant role of AGN outflows in explaining the IceCube data appears in any case to be ruled out.

La inserción al Asia-Pacífico, oportunidades y desafíos para el Valle del Cauca y la región pacífica colombiana

OpenAIRE

Ricardo Coutin

2014-01-01

Resumen: El objetivo general del texto es brindar una aproximación a los retos y las oportunidades que representa, para el Valle del Cauca y la Región Pacífica colombiana, la inserción al Asia-Pacífico. Para lo cual se plantean tres objetivos específicos: primero, analizar someramente el contexto económico comercial del Asia-Pacífico y América Latina, con especial énfasis en Colombia y los demás países de la Alianza del Pacífico (AP); segundo, estudiar las oportunidades y los retos para el Va...

La inserción al Asia-Pacífico, oportunidades y desafíos para el Valle del Cauca y la región pacífica colombiana

OpenAIRE

Countin, Ricardo

2014-01-01

El objetivo general del texto es brindar una aproximación a los retos y las oportunidades que representa, para el Valle del Cauca y la Región Pacífica colombiana, la inserción al Asia-Pacífico. Para lo cual se plantean tres objetivos específicos: primero, analizar someramente el contexto económico comercial del Asia-Pacífico y América Latina, con especial énfasis en Colombia y los demás países de la Alianza del Pacífico (AP); segundo, estudiar las oportunidades y los retos para el Valle del C...

Molecular outflows in the L1641 region of Orion

International Nuclear Information System (INIS)

Morgan, J.A.

1990-01-01

Little is known about the interaction between molecular outflows associated with young stellar objects and the parent molecular cloud that produced them. This is because molecular outflows are a recently discovered phenomenon and, so, have not had their global properties studied in great detail and molecular clouds were not mapped to sufficiently high spatial resolution to resolve the interaction. The interaction between molecular outflows and the L1641 molecular cloud is addressed by both identifying and mapping all the molecular outflows as well as the detailed structure of the cloud. Candidate molecular outflows were found from single point 12-CO observations of young stellar objects identified from the IRAS survey data. The candidate sources were then mapped to confirm their molecular outflow nature. From these maps, molecular outflow characteristics such as their morphology, orientation, and energetics were determined. In addition, the Orion molecular cloud was mapped to compare directly with the molecular outflows. The molecular outflows identified were found to have rising infrared spectra, radio continuum emission that suggests a stellar wind or optically thick H II region, and molecular line strengths that indicate that they are embedded within a very dense environment. The lack of an optical counterpart for many molecular outflows suggests that they occur at the earliest stages of stellar evolution. The lack of an optical counterpart for many molecular outflows suggest that they occur at the earliest stages of stellar evolution. The orientations of the molecular outflows appear to lie in no preferred direction and they have shapes that indicate that the molecular cloud is responsible for determining their direction and collimation

LENS MODELS OF HERSCHEL-SELECTED GALAXIES FROM HIGH-RESOLUTION NEAR-IR OBSERVATIONS

Energy Technology Data Exchange (ETDEWEB)

Calanog, J. A.; Cooray, A.; Ma, B.; Casey, C. M. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Fu, Hai [Department of Physics and Astronomy, University of Iowa, Van Allen Hall, Iowa City, IA 52242 (United States); Wardlow, J. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Amber, S. [Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA (United Kingdom); Baker, A. J. [Department of Physics and Astronomy, Rutgers, The State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Baes, M. [1 Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281, B-9000 Gent (Belgium); Bock, J. [California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States); Bourne, N.; Dye, S. [School of Physics and Astronomy, University of Nottingham, NG7 2RD (United Kingdom); Bussmann, R. S. [Department of Astronomy, Space Science Building, Cornell University, Ithaca, NY 14853-6801 (United States); Chapman, S. C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Clements, D. L. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Conley, A. [Center for Astrophysics and Space Astronomy 389-UCB, University of Colorado, Boulder, CO 80309 (United States); Dannerbauer, H. [Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu-CNRS-Université Paris Diderot, CE-Saclay, pt courrier 131, F-91191 Gif-sur-Yvette (France); De Zotti, G. [INAF-Osservatorio Astronomico di Padova, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy); Dunne, L.; Eales, S. [School of Physics and Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff CF24 3AA (United Kingdom); and others

2014-12-20

We present Keck-Adaptive Optics and Hubble Space Telescope high resolution near-infrared (IR) imaging for 500 μm bright candidate lensing systems identified by the Herschel Multi-tiered Extragalactic Survey and Herschel Astrophysical Terahertz Large Area Survey. Out of 87 candidates with near-IR imaging, 15 (∼17%) display clear near-IR lensing morphologies. We present near-IR lens models to reconstruct and recover basic rest-frame optical morphological properties of the background galaxies from 12 new systems. Sources with the largest near-IR magnification factors also tend to be the most compact, consistent with the size bias predicted from simulations and previous lensing models for submillimeter galaxies (SMGs). For four new sources that also have high-resolution submillimeter maps, we test for differential lensing between the stellar and dust components and find that the 880 μm magnification factor (μ{sub 880}) is ∼1.5 times higher than the near-IR magnification factor (μ{sub NIR}), on average. We also find that the stellar emission is ∼2 times more extended in size than dust. The rest-frame optical properties of our sample of Herschel-selected lensed SMGs are consistent with those of unlensed SMGs, which suggests that the two populations are similar.

ALMA Dust Polarization Observations of Two Young Edge-on Protostellar Disks

Science.gov (United States)

Lee, Chin-Fei; Li, Zhi-Yun; Ching, Tao-Chung; Lai, Shih-Ping; Yang, Haifeng

2018-02-01

Polarized emission is detected in two young nearly edge-on protostellar disks in 343 GHz continuum at ∼50 au (∼0.″12) resolution with Atacama Large Millimeter/submillimeter Array. One disk is in HH 212 (Class 0) and the other in the HH 111 (early Class I) protostellar system. The polarization fraction is ∼1%. The disk in HH 212 has a radius of ∼60 au. The emission is mainly detected from the nearside of the disk. The polarization orientations are almost perpendicular to the disk major axis, consistent with either self-scattering or emission by grains aligned with a poloidal field around the outer edge of the disk because of the optical depth effect and temperature gradient; the presence of a poloidal field would facilitate the launching of a disk wind, for which there is already tentative evidence in the same source. The disk of HH 111 VLA 1 has a larger radius of ∼220 au and is thus more resolved. The polarization orientations are almost perpendicular to the disk major axis in the nearside, but more along the major axis in the farside, forming roughly half of an elliptical pattern there. It appears that toroidal and poloidal magnetic field may explain the polarization on the near and far sides of the disk, respectively. However, it is also possible that the polarization is due to self-scattering. In addition, alignment of dust grains by radiation flux may play a role in the farside. Our observations reveal a diversity of disk polarization patterns that should be taken into account in future modeling efforts.

Radiology department design to accommodate the future introduction of global PACS

International Nuclear Information System (INIS)

Naylor, A.F.

1992-01-01

In the light of the continuing development of pictorial archiving and communication systems (PACS) and image management and communications (MACS) systems it is appropriate to consider the provision that should be made in the design of a new or renovated department of radiology to accommodate these new technologies at either an earlier or later date. This paper considers 3 particular aspects of the influence of PACS on future department design: 1) the requirement for either more or less total department gross square feet, 2) the provision for the specific allocation of spaces at certain locations for PACS equipment and functions, and 3) the provision for dedicated pathways for fiber optic communications among the many locations in the department where PACS components would be located. (author). 1 fig

Does PACS improve diagnostic accuracy in chest radiograph interpretations in clinical practice?

International Nuclear Information System (INIS)

Hurlen, Petter; Borthne, Arne; Dahl, Fredrik A.; Østbye, Truls; Gulbrandsen, Pål

2012-01-01

Objectives: To assess the impact of a Picture Archiving and Communication System (PACS) on the diagnostic accuracy of the interpretation of chest radiology examinations in a “real life” radiology setting. Materials and methods: During a period before PACS was introduced to radiologists, when images were still interpreted on film and reported on paper, images and reports were also digitally stored in an image database. The same database was used after the PACS introduction. This provided a unique opportunity to conduct a blinded retrospective study, comparing sensitivity (the main outcome parameter) in the pre and post-PACS periods. We selected 56 digitally stored chest radiograph examinations that were originally read and reported on film, and 66 examinations that were read and reported on screen 2 years after the PACS introduction. Each examination was assigned a random number, and both reports and images were scored independently for pathological findings. The blinded retrospective score for the original reports were then compared with the score for the images (the gold standard). Results: Sensitivity was improved after the PACS introduction. When both certain and uncertain findings were included, this improvement was statistically significant. There were no other statistically significant changes. Conclusion: The result is consistent with prospective studies concluding that diagnostic accuracy is at least not reduced after PACS introduction. The sensitivity may even be improved.

Biorheological Model on Flow of Herschel-Bulkley Fluid through a Tapered Arterial Stenosis with Dilatation.

Science.gov (United States)

Priyadharshini, S; Ponalagusamy, R

2015-01-01

An analysis of blood flow through a tapered artery with stenosis and dilatation has been carried out where the blood is treated as incompressible Herschel-Bulkley fluid. A comparison between numerical values and analytical values of pressure gradient at the midpoint of stenotic region shows that the analytical expression for pressure gradient works well for the values of yield stress till 2.4. The wall shear stress and flow resistance increase significantly with axial distance and the increase is more in the case of converging tapered artery. A comparison study of velocity profiles, wall shear stress, and flow resistance for Newtonian, power law, Bingham-plastic, and Herschel-Bulkley fluids shows that the variation is greater for Herschel-Bulkley fluid than the other fluids. The obtained velocity profiles have been compared with the experimental data and it is observed that blood behaves like a Herschel-Bulkley fluid rather than power law, Bingham, and Newtonian fluids. It is observed that, in the case of a tapered stenosed tube, the streamline pattern follows a convex pattern when we move from r/R = 0 to r/R = 1 and it follows a concave pattern when we move from r/R = 0 to r/R = -1. Further, it is of opposite behaviour in the case of a tapered dilatation tube which forms new information that is, for the first time, added to the literature.

Herschel-ATLAS : Planck sources in the phase 1 fields

NARCIS (Netherlands)

Herranz, D.; González-Nuevo, J.; Clements, D.; De, Zotti G.; Lopez-Caniego, M.; Lapi, A.; Rodighiero, G.; Danese, L.; Fu, H.; Cooray, A.; Baes, M.; Bendo, G.; Bonavera, L.; Carrera, F.; Dole, H.; Eales, S.; Ivison, R.; Jarvis, M.; Lagache, G.; Massardi, M.; Michalowski, M.; Negrello, M.; Rigby, E.E.; Scott, D.; Valiante, E.; Valtchanov, I.; Werf, van der P.P.; Auld, R.; Buttiglione, S.; Dariush, A.; Dunne, L.; Hopwood, R.; Hoyos, C.; Ibar, E.; Maddox, S.

2013-01-01

We present the results of a cross-correlation of the Planck Early Release Compact Source catalogue (ERCSC) with the catalogue of Herschel-ATLAS sources detected in the phase 1 fields, covering 134.55{deg}$^{2}$. There are 28 ERCSC sources detected by Planck at 857 GHz in this area. As many as 16 of

WEAVE: the next generation wide-field spectroscopy facility for the William Herschel Telescope : The next generation wide-field spectroscopy facility for the William Herschel Telescope

NARCIS (Netherlands)

Dalton, Gavin; Trager, Scott C.; Abrams, Don Carlos; Carter, David; Bonifacio, Piercarlo; Aguerri, J. Alfonso L.; MacIntosh, Mike; Evans, Chris; Lewis, Ian; Navarro, Ramon; Agocs, Tibor; Dee, Kevin; Rousset, Sophie; Tosh, Ian; Middleton, Kevin; Pragt, Johannes; Terrett, David; Brock, Matthew; Benn, Chris; Verheijen, Marc; Cano Infantes, Diego; Bevil, Craige; Steele, Iain; Mottram, Chris; Bates, Stuart; Gribbin, Francis J.; Rey, Jürg; Rodriguez, Luis Fernando; Delgado, Jose Miguel; Guinouard, Isabelle; Walton, Nic; Irwin, Michael J.; Jagourel, Pascal; Stuik, Remko; Gerlofsma, Gerrit; Roelfsma, Ronald; Skillen, Ian; Ridings, Andy; Balcells, Marc; Daban, Jean-Baptiste; Gouvret, Carole; Venema, Lars; Girard, Paul

We present the preliminary design of the WEAVE next generation spectroscopy facility for the William Herschel Telescope (WHT), principally targeting optical ground-based follow up of upcoming ground-based (LOFAR) and spacebased (Gaia) surveys. WEAVE is a multi-object and multi-IFU facility utilizing

The Herschel-SPIRE Legacy Survey (HSLS): the scientific goals of a shallow and wide submillimeter imaging survey with SPIRE

NARCIS (Netherlands)

Cooray, Asantha; Eales, Steve; Chapman, Scott; Clements, David L.; Dore, Olivier; Farrah, Duncan; Jarvis, Matt J.; Kaplinghat, Manoj; Negrello, Mattia; Melchiorri, Alessandro; Peiris, Hiranya; Pope, Alexandra; Santos, Mario G.; Serjeant, Stephen; Thompson, Mark; White, Glenn; Amblard, Alexandre; Banerji, Manda; Corasaniti, Pier-Stefano; Das, Sudeep; de Bernardis, Francesco; de Zotti, Gianfranco; Giannantonio, Tommaso; Gonzalez-Nuevo Gonzalez, Joaquin; Khostovan, Ali Ahmad; Mitchell-Wynne, Ketron; Serra, Paolo; Song, Yong-Seon; Vieira, Joaquin; Wang, Lingyu; Zemcov, Michael; Abdalla, Filipe; Afonso, Jose; Aghanim, Nabila; Andreani, Paola; Aretxaga, Itziar; Auld, Robbie; Baes, Maarten; Baker, Andrew; Barkats, Denis; Belen Barreiro, R.; Bartolo, Nicola; Barton, Elizabeth; Barway, Sudhanshu; Stefano Battistelli, Elia; Baugh, Carlton; Holwerda, Benne W.; Koopmans, Leon; Pohlen, Michael; Vegetti, Simona

2010-01-01

A large sub-mm survey with Herschel will enable many exciting science opportunities, especially in an era of wide-field optical and radio surveys and high resolution cosmic microwave background experiments. The Herschel-SPIRE Legacy Survey (HSLS), will lead to imaging data over 4000 sq. degrees at

PAC and μSr investigations of light interstitial diffusion in intermetallic hydrides

International Nuclear Information System (INIS)

Boyer, P.; Baudry, A.

1988-01-01

Specific aspects of the Perturbed Angular Correlation (PAC) of gamma rays concerning its application to the study of atomic diffusion in solids are presented. PAC results recently obtained on the 181 Ta probe in several crystalline and amorphous phases of Zr 2 Ni hydrides are briefly summarized. Preliminary μSR results relative to these intermetallic hydrides are presented and compared to the PAC data

revealing H{sub 2}D{sup +} depletion and compact structure in starless and protostellar cores with ALMA

Energy Technology Data Exchange (ETDEWEB)

Friesen, R. K. [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St George Street, Toronto, ON M5S 3H4 (Canada); Di Francesco, J. [National Research Council Canada, Radio Astronomy Program, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Bourke, T. L. [Radio and Geoastronomy Division, Harvard Smithsonian Center for Astrophysics, MS-42, Cambridge, MA 02138 (United States); Caselli, P. [Max-Planck-Institute for Extraterrestrial Physics, Giessenbachstrasse 1, D-85748 Garching (Germany); Jørgensen, J. K. [Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen Ø. (Denmark); Pineda, J. E. [Institute for Astronomy, ETH Zürich, Wolfgang-Pauli-Strasse 27, CH-8093 Zürich (Switzerland); Wong, M., E-mail: friesen@dunlap.utoronto.ca [University of British Columbia, Vancouver, BC V6T 1Z4 (Canada)

2014-12-10

We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of the submillimeter dust continuum and H{sub 2}D{sup +} 1{sub 10}-1{sub 11} emission toward two evolved, potentially protostellar cores within the Ophiuchus molecular cloud, Oph A SM1 and SM1N. The data reveal small-scale condensations within both cores, with mass upper limits of M ≲ 0.02 M {sub ☉} (∼20 M {sub Jup}). The SM1 condensation is consistent with a nearly symmetric Gaussian source with a width of only 37 AU. The SM1N condensation is elongated and extends 500 AU along its major axis. No evidence for substructure is seen in either source. A Jeans analysis indicates that these sources are unlikely to fragment, suggesting that both will form single stars. H{sub 2}D{sup +} is only detected toward SM1N, offset from the continuum peak by ∼150-200 AU. This offset may be due to either heating from an undetected, young, low-luminosity protostellar source or first hydrostatic core, or HD (and consequently H{sub 2}D{sup +}) depletion in the cold center of the condensation. We propose that SM1 is protostellar and that the condensation detected by ALMA is a warm (T ∼ 30-50 K) accretion disk. The less concentrated emission of the SM1N condensation suggests that it is still starless, but we cannot rule out the presence of a low-luminosity source, perhaps surrounded by a pseudodisk. These data observationally reveal the earliest stages of the formation of circumstellar accretion regions and agree with theoretical predictions that disk formation can occur very early in the star formation process, coeval with or just after the formation of a first hydrostatic core or protostar.

Acquisition and analysis of throughput rates for an operational department-wide PACS

Science.gov (United States)

Stewart, Brent K.; Taira, Ricky K.; Dwyer, Samuel J., III; Huang, H. K.

1992-07-01

The accurate prediction of image throughput is a critical issue in planning for and acquisition of any successful Picture Archiving and Communication System (PACS). Bottlenecks or design flaws can render an expensive PACS implementation useless. This manuscript presents a method for accurately predicting and measuring image throughput of a PACS design. To create the simulation model of the planned or implemented PACS, it must first be decomposed into principal tasks. We have decomposed the entire PACS image management chain into eight subsystems. These subsystems include network transfers over three different networks (Ethernet, FDDI and UltraNet) and five software programs and/or queues: (1) transfer of image data from the imaging modality computer to the image acquisition/reformatting computer; (2) reformatting the image data into a standard image format; (3) transferring the image data from the acquisition/reformatting computer to the image archive computer; (4) updating a relational database management system over the network; (5) image processing-- rotation and optimal gray-scale lookup table calculation; (6) request that the image be archived; (7) image transfer from the image archive computer to a designated image display workstation; and (8) update the local database on the image display station, separate the image header from the image data and store the image data on a parallel disk array. Through development of an event logging facility and implementation of a network management package we have acquired throughput data for each subsystem in the PACS chain. In addition, from our PACS relational database management system, we have distilled the traffic generation patterns (temporal, file size and destination) of our imaging modality devices. This data has been input into a simulation modeling package (Block Oriented Network Simulator-- BONeS) to estimate the characteristics of the modeled PACS, e.g., the throughput rates and delay time. This simulation

The unforgotten sisters female astronomers and scientists before Caroline Herschel

CERN Document Server

Bernardi, Gabriella

2016-01-01

Taking inspiration from Siv Cedering’s poem in the form of a fictional letter from Caroline Herschel that refers to “my long, lost sisters, forgotten in the books that record our science”, this book tells the lives of twenty-five female scientists, with specific attention to astronomers and mathematicians. Each of the presented biographies is organized as a kind of "personal file" which sets the biographee’s life in its historical context, documents her main works, highlights some curious facts, and records citations about her. The selected figures are among the most representative of this neglected world, including such luminaries as Hypatia of Alexandra, Hildegard of Bingen, Elisabetha Hevelius, and Maria Gaetana Agnesi. They span a period of about 4000 years, from En HeduAnna, the Akkadian princess, who was one of the first recognized female astronomers, to the dawn of the era of modern astronomy with Caroline Herschel and Mary Somerville. The book will be of interest to all who wish to learn more ...

Studies of Quasar Outflows

Science.gov (United States)

Arav, Nahum

2002-01-01

The main aim of this research program is to determine the ionization equilibrium and abundances in quasar outflows. Especially in the broad absorption line QSO PG 0946+301. We find that the outflow's metalicity is consistent with being solar, while the abundance ratio of phosphorus to other metals is at least ten times solar. These findings are based on diagnostics that are not sensitive to saturation and partial covering effects in the BALs (Broad Adsorption Lines), which considerably weakened previous claims for enhanced metalicity. Ample evidence for these effects is seen in the spectrum.

SUBMILLIMETER LINE SPECTRUM OF THE SEYFERT GALAXY NGC 1068 FROM THE HERSCHEL-SPIRE FOURIER TRANSFORM SPECTROMETER

Energy Technology Data Exchange (ETDEWEB)

Spinoglio, Luigi; Pereira-Santaella, Miguel; Busquet, Gemma [Istituto di Astrofisica e Planetologia Spaziali, INAF-IAPS, Via Fosso del Cavaliere 100, I-00133 Roma (Italy); Schirm, Maximilien R. P.; Wilson, Christine D.; Parkin, Tara J. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1 (Canada); Glenn, Jason; Kamenetzky, Julia; Rangwala, Naseem; Maloney, Philip R. [Center for Astrophysics and Space Astronomy, 389-UCB, University of Colorado, Boulder, CO 80303 (United States); Bendo, George J. [UK ALMA Regional Centre Node, Jordell Bank Center for Astrophysics, School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Madden, Suzanne C. [CEA, Laboratoire AIM, Irfu/SAp, Orme des Merisiers, F-91191 Gif-sur-Yvette (France); Wolfire, Mark G. [Astronomy Department, University of Maryland, College Park, MD 20742 (United States); Boselli, Alessandro [Laboratoire d' Astrophysique de Marseille-LAM, Universite d' Aix-Marseille and CNRS, UMR7326, 38 rue F. Joliot-Curie, F-13388 Marseille Cedex 13 (France); Cooray, Asantha [Center for Cosmology, Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Page, Mathew J., E-mail: luigi.spinoglio@iaps.inaf.it [Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom)

2012-10-20

The first complete submillimeter spectrum (190-670 {mu}m) of the Seyfert 2 galaxy NGC 1068 has been observed with the SPIRE Fourier transform spectrometer on board the Herschel Space Observatory. The sequence of CO lines (J {sub up} = 4-13), lines from H{sub 2}O, the fundamental rotational transition of hydrogen fluoride, two o-H{sub 2}O{sup +} lines, and one line each from CH{sup +} and OH{sup +} have been detected, together with the two [C I] lines and the [N II] 205 {mu}m line. The observations in both single pointing mode with sparse image sampling and in mapping mode with full image sampling allow us to disentangle two molecular emission components, one due to the compact circumnuclear disk (CND) and one from the extended region encompassing the star-forming ring (SF-ring). Radiative transfer models show that the two CO components are characterized by densities of n(H{sub 2}) = 10{sup 4.5} and 10{sup 2.9} cm{sup -3} and temperatures of T {sub kin} = 100 K and 127 K, respectively. A comparison of the CO line intensities with the photodissociation region (PDR) and X-ray-dominated region (XDR) models, together with the other observational constraints, such as the observed CO surface brightness and the radiation field, indicates that the best explanation for the CO excitation of the CND is an XDR with a density of n(H{sub 2}) {approx} 10{sup 4} cm{sup -3} and an X-ray flux of 9 erg s{sup -1} cm{sup -2}, consistent with illumination by the active galactic nucleus, while the CO lines in the SF-ring are better modeled by a PDR. The detected water transitions, together with those observed with the Herschel PACS spectrometer, can be modeled by a large velocity gradient model with low temperature (T {sub kin} {approx} 40 K) and high density (n(H{sub 2}) in the range 10{sup 6.7}-10{sup 7.9} cm{sup -3}). The emission of H{sub 2}O{sup +} and OH{sup +} are in agreement with PDR models with cosmic-ray ionization. The diffuse ionized atomic component observed through the [N

Scientific programming on massively parallel processor CP-PACS

International Nuclear Information System (INIS)

Boku, Taisuke

1998-01-01

The massively parallel processor CP-PACS takes various problems of calculation physics as the object, and it has been designed so that its architecture has been devised to do various numerical processings. In this report, the outline of the CP-PACS and the example of programming in the Kernel CG benchmark in NAS Parallel Benchmarks, version 1, are shown, and the pseudo vector processing mechanism and the parallel processing tuning of scientific and technical computation utilizing the three-dimensional hyper crossbar net, which are two great features of the architecture of the CP-PACS are described. As for the CP-PACS, the PUs based on RISC processor and added with pseudo vector processor are used. Pseudo vector processing is realized as the loop processing by scalar command. The features of the connection net of PUs are explained. The algorithm of the NPB version 1 Kernel CG is shown. The part that takes the time for processing most in the main loop is the product of matrix and vector (matvec), and the parallel processing of the matvec is explained. The time for the computation by the CPU is determined. As the evaluation of the performance, the evaluation of the time for execution, the short vector processing of pseudo vector processor based on slide window, and the comparison with other parallel computers are reported. (K.I.)

Inventing a space mission the story of the Herschel space observatory

CERN Document Server

Minier, Vincent; Bontems, Vincent; de Graauw, Thijs; Griffin, Matt; Helmich, Frank; Pilbratt, Göran; Volonte, Sergio

2017-01-01

This book describes prominent technological achievements within a very successful space science mission: the Herschel space observatory. Focusing on the various processes of innovation it offers an analysis and discussion of the social, technological and scientific context of the mission that paved the way to its development. It addresses the key question raised by these processes in our modern society, i.e.: how knowledge management of innovation set the conditions for inventing the future? In that respect the book is based on a transdisciplinary analysis of the programmatic complexity of Herschel, with inputs from space scientists, managers, philosophers, and engineers. This book is addressed to decision makers, not only in space science, but also in other industries and sciences using or building large machines. It is also addressed to space engineers and scientists as well as students in science and management.

Knowledge Outflows from Foreign Subsidiaries

DEFF Research Database (Denmark)

Perri, Alessandra; Andersson, Ulf

This paper analyzes the MNC subsidiaries’ trade-off between the need for knowledge creation and the need for knowledge protection, and relates it to the extent of knowledge outflows generated within the host location. Combining research in International Business with Social Theory, we find...... the value of the subsidiary’s knowledge stock is very high, the need for knowledge protection restrains reciprocity mechanisms in knowledge exchanges, thus reducing the extent of knowledge outflows to the host location. This study contributes to the literature on the firm-level antecedents of FDI...... that subsidiaries that extensively draw on external knowledge sources are also more likely to generate knowledge outflows to local firms. We argue that this may be explained by the subsidiaries’ willingness to build the trust that facilitates the establishment of reciprocal knowledge linkages. However, when...

Integration of a clinical trial database with a PACS

International Nuclear Information System (INIS)

Van Herk, M

2014-01-01

Many clinical trials use Electronic Case Report Forms (ECRF), e.g., from OpenClinica. Trial data is augmented if DICOM scans, dose cubes, etc. from the Picture Archiving and Communication System (PACS) are included for data mining. Unfortunately, there is as yet no structured way to collect DICOM objects in trial databases. In this paper, we obtain a tight integration of ECRF and PACS using open source software. Methods: DICOM identifiers for selected images/series/studies are stored in associated ECRF events (e.g., baseline) as follows: 1) JavaScript added to OpenClinica communicates using HTML with a gateway server inside the hospitals firewall; 2) On this gateway, an open source DICOM server runs scripts to query and select the data, returning anonymized identifiers; 3) The scripts then collects, anonymizes, zips and transmits selected data to a central trial server; 4) Here data is stored in a DICOM archive which allows authorized ECRF users to view and download the anonymous images associated with each event. Results: All integration scripts are open source. The PACS administrator configures the anonymization script and decides to use the gateway in passive (receiving) mode or in an active mode going out to the PACS to gather data. Our ECRF centric approach supports automatic data mining by iterating over the cases in the ECRF database, providing the identifiers to load images and the clinical data to correlate with image analysis results. Conclusions: Using open source software and web technology, a tight integration has been achieved between PACS and ECRF.

Introduction to PAC-experiments and hyperfine interaction measurements in solids

International Nuclear Information System (INIS)

Manasijevic, M.; Koicki, S.; Cekic, B.; Ivanovic, N.; Milosevic, Z.; Koteski, V.; Radisavljevic, I.; Cavor, J.; Marjanovic, D.

2001-01-01

Perturbed angular correlation (PAC) has for many years been a productive experimental technique for obtaining information about the static and dynamic behaviour of local and electronic structures of solids on a microscope scale, without changing the main properties of the material. This article contains an outline of the basic principles of PAC. A summary of the technique and experimental requirements is given, followed by a brief discussion of the parameters which can be extracted from the PAC measurements. Some examples then illustrate the recent developments in the applications to problems of interest for solid state physics nad materials science, performed in VINCA Institute. (author)

Does the X-ray outflow quasar PDS 456 have a UV outflow at 0.3c?

Science.gov (United States)

Hamann, Fred; Chartas, George; Reeves, James; Nardini, Emanuele

2018-05-01

The quasar PDS 456 (at redshift ˜0.184) has a prototype ultra-fast outflow (UFO) measured in X-rays. This outflow is highly ionized with relativistic speeds, large total column densities log NH(cm-2) > 23, and large kinetic energies that could be important for feedback to the host galaxy. A UV spectrum of PDS 456 obtained with the Hubble Space Telescope in 2000 contains one well-measured broad absorption line (BAL) at ˜1346 Å (observed) that might be Ly α at v ≈ 0.06c or N V λ1240 at v ≈ 0.08c. However, we use photoionization models and comparisons to other outflow quasars to show that these BAL identifications are problematic because other lines that should accompany them are not detected. We argue that the UV BAL is probably C IV at v ≈ 0.30c. This would be the fastest UV outflow ever reported, but its speed is similar to the X-ray outflow and its appearance overall is similar to relativistic UV BALs observed in other quasars. The C IV BAL identification is also supported indirectly by the tentative detection of another broad C IV line at v ≈ 0.19c. The high speeds suggest that the UV outflow originates with the X-ray UFO crudely 20-30 rg from the central black hole. We speculate that the C IV BAL might form in dense clumps embedded in the X-ray UFO, requiring density enhancements of only ≳0.4 dex compared to clumpy structures already inferred for the soft X-ray absorber in PDS 456. The C IV BAL might therefore be the first detection of low-ionization clumps proposed previously to boost the opacities in UFOs for radiative driving.

The sphere-PAC fuel code 'SPHERE-3'

Energy Technology Data Exchange (ETDEWEB)

Wallin, H

2000-07-01

Sphere-PAC fuel is an advanced nuclear fuel, in which the cladding tube is filled with small fuel spheres instead of the more usual fuel pellets. At PSI, the irradiation behaviour of sphere-PAC fuel is calculated using the computer code SPHERE-3. The paper describes the present status of the SPHERE-3 code, and some results of the qualification process against experimental data. (author)

VARIABLE ACCRETION OUTBURSTS IN PROTOSTELLAR EVOLUTION

International Nuclear Information System (INIS)

Bae, Jaehan; Hartmann, Lee; Zhu, Zhaohuan; Gammie, Charles

2013-01-01

We extend the one-dimensional, two-zone models of long-term protostellar disk evolution with infall of Zhu et al. to consider the potential effects of a finite viscosity in regions where the ionization is too low for the magnetorotational instability (MRI) to operate (the d ead zone ) . We find that the presence of a small but finite dead zone viscosity, as suggested by simulations of stratified disks with MRI-active outer layers, can trigger inside-out bursts of accretion, starting at or near the inner edge of the disk, instead of the previously found outside-in bursts with zero dead zone viscosity, which originate at a few AU in radius. These inside-out bursts of accretion bear a qualitative resemblance to the outburst behavior of one FU Ori object, V1515 Cyg, in contrast to the outside-in burst models, which more closely resemble the accretion events in FU Ori and V1057 Cyg. Our results suggest that the type and frequency of outbursts are potentially a probe of transport efficiency in the dead zone. Simulations must treat the inner disk regions, R ∼< 0.5 AU, to show the detailed time evolution of accretion outbursts in general and to observe the inside-out bursts in particular.

VARIABLE ACCRETION OUTBURSTS IN PROTOSTELLAR EVOLUTION

Energy Technology Data Exchange (ETDEWEB)

Bae, Jaehan; Hartmann, Lee [Department of Astronomy, University of Michigan, 500 Church St., Ann Arbor, MI 48105 (United States); Zhu, Zhaohuan [Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Peyton Hall, Princeton, NJ 08544 (United States); Gammie, Charles, E-mail: jaehbae@umich.edu, E-mail: lhartm@umich.edu, E-mail: zhuzh@astro.princeton.edu, E-mail: gammie@illinois.edu [Department of Astronomy, University of Illinois Urbana-Champaign, 1002 W. Green St., Urbana, IL 61801 (United States)

2013-02-20

We extend the one-dimensional, two-zone models of long-term protostellar disk evolution with infall of Zhu et al. to consider the potential effects of a finite viscosity in regions where the ionization is too low for the magnetorotational instability (MRI) to operate (the {sup d}ead zone{sup )}. We find that the presence of a small but finite dead zone viscosity, as suggested by simulations of stratified disks with MRI-active outer layers, can trigger inside-out bursts of accretion, starting at or near the inner edge of the disk, instead of the previously found outside-in bursts with zero dead zone viscosity, which originate at a few AU in radius. These inside-out bursts of accretion bear a qualitative resemblance to the outburst behavior of one FU Ori object, V1515 Cyg, in contrast to the outside-in burst models, which more closely resemble the accretion events in FU Ori and V1057 Cyg. Our results suggest that the type and frequency of outbursts are potentially a probe of transport efficiency in the dead zone. Simulations must treat the inner disk regions, R {approx}< 0.5 AU, to show the detailed time evolution of accretion outbursts in general and to observe the inside-out bursts in particular.

Implementation of MINI-PACS using the DICOM converter on the Web

International Nuclear Information System (INIS)

Ji, Youn Sang

2000-01-01

In recent years, medical procedures have become more complex, while financial pressures for shortened hospital stays and increased efficiency in patient care have increased. As a result, several shortcomings of present film-based systems for managing medical images have become apparent. Maintaining film space is labor intensive and consumes valuable space. Because only single copies of radiological examinations exist, they are prone to being lost or misplaced, thereby consuming additional valuable time and expense. In this paper, MINI-PACS for image archiving, transmission, and viewing offers a solution to these problems. Proposed MINI-PACS consists of mainly four parts such as Web Module, Client-Server Module, Internal Module, Acquisition Module. In addition, MINI-PACS system includes DICOM Converter that Non-DICOM file format converts standard file format. In Client-Server Module case, Proposed system is combined both SCU(Service Class User: Client) part and SCP(Service Class Provider: Server) part therefore this system provides the high resolution image processing techniques based on windows platform. Because general PACS system is too expensive for Medium and Small hospitals to install and operate the full-PACS. Also, we constructed Web Module for database connection through the WWW.=20

Nondimensional quasi-steady analysis of magnetorheological dampers utilizing a Herschel-Bulkley model with preyield viscosity

Science.gov (United States)

John, Shaju; Wereley, Norman M.

2003-07-01

Dampers based on electrorheological (ER) and magnetorheolgical (MR) fluids can be analyzed under assumptions of quasi-steady, fully developed flow behavior. Models that have been used to characterize ER and MR dampers include the Bingham-plastic, the Herschel-Bulkley and biviscous models. In the Bingham-plastic and the Herschel-Bulkley models, the fluid exhibits rigid behavior in the preyield flow region. The difference between these two models lie in the modeling of the postyield behavior. In the case of the Bingham-plastic model, the postyield behavior is such that the shear stress is proportional to the shear rate. In contrast, the Herschel-Bulkley model assumes that the shear stress is proportional to a power law of the shearrate. In the biciscous model, the relationship between the shear stres and shear rate is linear in both the preyield and postyield regions with constant values of viscosities for the two regions. However, the preyield flow behavior exhibits a much high viscosity than that in the postyield. In the propose model, the assumption of preyield rigid behavior within the Herschel-Bulkley model has been relaxed while the postyield relationship based on the power law has been retained. Here the fluid undergoes Newtonian preyield viscous flow and has a non-Newtonian postyield behavior. Based on this model, we have analyzed the performance of a rectangular duct ER or MR valve. Typical results include shear stress and velocity profiles across the valve gap, equivalent damping and damping coefficients.

Biorheological Model on Flow of Herschel-Bulkley Fluid through a Tapered Arterial Stenosis with Dilatation

Directory of Open Access Journals (Sweden)

S. Priyadharshini

2015-01-01

Full Text Available An analysis of blood flow through a tapered artery with stenosis and dilatation has been carried out where the blood is treated as incompressible Herschel-Bulkley fluid. A comparison between numerical values and analytical values of pressure gradient at the midpoint of stenotic region shows that the analytical expression for pressure gradient works well for the values of yield stress till 2.4. The wall shear stress and flow resistance increase significantly with axial distance and the increase is more in the case of converging tapered artery. A comparison study of velocity profiles, wall shear stress, and flow resistance for Newtonian, power law, Bingham-plastic, and Herschel-Bulkley fluids shows that the variation is greater for Herschel-Bulkley fluid than the other fluids. The obtained velocity profiles have been compared with the experimental data and it is observed that blood behaves like a Herschel-Bulkley fluid rather than power law, Bingham, and Newtonian fluids. It is observed that, in the case of a tapered stenosed tube, the streamline pattern follows a convex pattern when we move from r/R=0 to r/R=1 and it follows a concave pattern when we move from r/R=0 to r/R=-1. Further, it is of opposite behaviour in the case of a tapered dilatation tube which forms new information that is, for the first time, added to the literature.

Do pulmonary artery catheters cause or increase tricuspid or pulmonic valvular regurgitation?

Science.gov (United States)

Sherman, S V; Wall, M H; Kennedy, D J; Brooker, R F; Butterworth, J

2001-05-01

There are few quantitative data on the extent or mechanism of pulmonary artery catheter (PAC)-induced valvular dysfunction. We hypothesized that PACs cause or worsen tricuspid and pulmonic valvular regurgitation, and tested this hypothesis by using transesophageal echocardiography. In 54 anesthetized adult patients, we measured color Doppler jet areas of tricuspid regurgitation (TR) in two planes (midesophageal [ME] 4-chamber and right ventricular inflow-outflow views) and pulmonic insufficiency (PI) in one plane (ME aortic valve long-axis view), both before and after we advanced a PAC into the pulmonary artery. Regurgitant jet areas and hemodynamic measurements were compared by using paired t-test. There were no significant changes in blood pressure or heart rate after passage of the PAC. After PAC placement, the mean PI jet area was not significantly increased. The mean TR jet area increased significantly in the right ventricular inflow-outflow view (+0.37 +/- 0.11 cm(2)) (P = 0.0014), but did not increase at the ME 4-chamber view. Seventeen percent of patients had an increase in TR jet area > or =1 cm(2); 8% of patients had an increase in PI jet area >/=1 cm(2). In patients without pulmonic or tricuspid valvular pathology, placement of a pulmonary artery catheter (PAC) worsened tricuspid regurgitation, which is consistently visualized in the right ventricular inflow-outflow view, and often not seen in the midesophageal 4-chamber view. This is consistent with malcoaptation of the anterior and posterior leaflets. PAC-induced pulmonic insufficiency was rarely detected in the midesophageal aortic valve long-axis view. We conclude that a PAC is very unlikely to be the sole cause of severe tricuspid regurgitation or pulmonic insufficiency.

75 FR 80082 - State, Local, Tribal, And Private Sector Policy Advisory Committee (SLTPS-PAC)

Science.gov (United States)

2010-12-21

..., Tribal, And Private Sector Policy Advisory Committee (SLTPS-PAC) AGENCY: Information Security Oversight... State, Local, Tribal, and Private Sector Policy Advisory Committee (SLTPS-PAC). The SLTPS-PAC will..., Tribal, and Private Sector Entities, as specified in Executive Order 13549 and its implementing directive...

Bioavailability of {sup 99m}Tc-paclitaxel-glucuronide ({sup 99m}Tc-PAC-G)

Energy Technology Data Exchange (ETDEWEB)

Biber Muftuler, F.Z.; Demir, I.; Uenack, P.; Ichedef, C.; Yurt Kilcar, A. [Ege Univ., Izmir (Turkey). Dept. of Nuclear Applications

2011-07-01

An antitumor agent paclitaxel (PAC) has been proved to be efficient in the treatment of breast and ovarian cancer. Glucuronic acid-derived paclitaxel compound (paclitaxel-glucuronide (PAC-G)) was enzymatically synthesized using microsome preparate separated from rat livers. The biodistribution mechanism of PAC-G in healthy female Albino Wistar rats has been investigated. The expected structure is confirmed according to LC/MS results, and the possible attachment is to C2-hydroxyl group. PAC-G was labeled with {sup 99m}Tc and the radiochemical yield of radiolabeled compound ({sup 99m}Tc-PAC-G) was 98.0 {+-} 02.74% (n=9). The range of the breast/blood and breast/muscle ratios is approximately between 3 and 35 in 240 min. All these experimental studies indicate that {sup 99m}Tc-PAC-G may potentially be used in breast tissue as an imaging agent. (orig.)

PACS/IMAC technology assessment

OpenAIRE

Schilling, Ronald B.

1997-01-01

According to Peter Ogle of Digital Imaging (San Francisco, CA), “Radiologists should help identify common values for the use of information technology in medicine.” Achieving a set of common values often requires a framework for organizing the thought process involved. That is the focus of this article in addressing the subject of picture archiving and communication system (PACS) technology assessment.

Calibration of the Herschel SPIRE Fourier Transform Spectrometer

OpenAIRE

Swinyard, Bruce; Polehampton, E. T.; Hopwood, R.; Valtchanov, I.; Lu, N.; Fulton, T.; Benielli, D.; Imhof, P.; Marchili, N.; Baluteau, J.- P.; Bendo, G. J.; Ferlet, M.; Griffin, Matthew Jason; Lim, T. L.; Makiwa, G.

2014-01-01

The Herschel Spectral and Photometric REceiver (SPIRE) instrument consists of an imaging photometric camera and an imaging Fourier Transform Spectrometer (FTS), both operating over a frequency range of ∼450–1550 GHz. In this paper, we briefly review the FTS design, operation, and data reduction, and describe in detail the approach taken to relative calibration (removal of instrument signatures) and absolute calibration against standard astronomical sources. The calibration scheme assumes a sp...

Herschel OBSERVATIONS OF DUST AROUND THE HIGH-MASS X-RAY BINARY GX 301-2

Energy Technology Data Exchange (ETDEWEB)

Servillat, M. [Laboratoire Univers et Théories (CNRS/INSU, Observatoire de Paris, Université Paris Diderot), 5 place Jules Janssen, F-92190 Meudon (France); Coleiro, A.; Chaty, S. [Laboratoire AIM (CEA/Irfu/SAp, CNRS/INSU, Universit Paris Diderot), CEA Saclay, Bat. 709, F-91191 Gif-sur-Yvette (France); Rahoui, F. [Harvard University, Department of Astronomy, 60 Garden Street, Cambridge, MA 02138 (United States); Zurita Heras, J. A., E-mail: mathieu.servillat@obspm.fr [AstroParticule et Cosmologie (Université Paris Diderot, CNRS/IN2P3, CEA/DSM, Observatoire de Paris, Sorbonne Paris Cité), 10 rue Alice Domon et Léonie Duquet, F-75205 Paris Cedex 13 (France)

2014-12-20

We aim at characterizing the structure of the gas and dust around the high-mass X-ray binary GX 301-2, a highly obscured X-ray binary hosting a hypergiant (HG) star and a neutron star, in order to better constrain its evolution. We used Herschel PACS to observe GX 301-2 in the far infrared and completed the spectral energy distribution of the source using published data or catalogs from the optical to the radio range (0.4 to 4 × 10{sup 4} μm). GX 301-2 is detected for the first time at 70 and 100 μm. We fitted different models of circumstellar (CS) environments to the data. All tested models are statistically acceptable, and consistent with an HG star at ∼3 kpc. We found that the addition of a free-free emission component from the strong stellar wind is required and could dominate the far-infrared flux. Through comparisons with similar systems and discussion on the estimated model parameters, we favor a disk-like CS environment of ∼8 AU that would enshroud the binary system. The temperature goes down to ∼200 K at the edge of the disk, allowing for dust formation. This disk is probably a rimmed viscous disk with an inner rim at the temperature of the dust sublimation temperature (∼1500 K). The similarities between the HG GX 301-2, B[e] supergiants, and the highly obscured X-ray binaries (particularly IGR J16318-4848) are strengthened. GX 301-2 might represent a transition stage in the evolution of massive stars in binary systems, connecting supergiant B[e] systems to luminous blue variables.

Cumulative neutrino background from quasar-driven outflows

Energy Technology Data Exchange (ETDEWEB)

Wang, Xiawei; Loeb, Abraham, E-mail: xiawei.wang@cfa.harvard.edu, E-mail: aloeb@cfa.harvard.edu [Department of Astronomy, Harvard University, 60 Garden Street, Cambridge, MA 02138 (United States)

2016-12-01

Quasar-driven outflows naturally account for the missing component of the extragalactic γ-ray background through neutral pion production in interactions between protons accelerated by the forward outflow shock and interstellar protons. We study the simultaneous neutrino emission by the same protons. We adopt outflow parameters that best fit the extragalactic γ-ray background data and derive a cumulative neutrino background of ∼ 10{sup −7} GeV cm{sup −2} s{sup −1} sr{sup −1} at neutrino energies E {sub ν} ∼> 10 TeV, which naturally explains the most recent IceCube data without tuning any free parameters. The link between the γ-ray and neutrino emission from quasar outflows can be used to constrain the high-energy physics of strong shocks at cosmological distances.

Negative and Positive Outflow-Feedback in Nearby (U)LIRGs

Energy Technology Data Exchange (ETDEWEB)

Cazzoli, Sara, E-mail: sara@iaa.es [Instituto de Astrofisica de Andalucia (CSIC), Granada (Spain)

2017-12-15

The starburst-AGN coexistence in local (U)LIRGs makes these galaxies excellent laboratories for the study of stellar and AGN outflows and feedback. Outflows regulate star formation and AGN activity, redistributing gas, dust and metals over large scales in the interstellar and intergalactic media (negative feedback) being also considered to be able to undergo vigorous star formation (positive feedback). In this contribution, I will summarize the results from a search for outflows in a sample of nearby 38 local (U)LIRG systems observed with VIMOS/VLT integral field unit. For two galaxies of the sample I will detail the outflow properties and discuss the observational evidence for negative and positive outflow-feedback. The assessment of both negative and positive feedback effects represent a novel approach toward a comprehensive understanding of the impact of outflow feedback in the galaxy evolution.

Implementation, reliability, and feasibility test of an Open-Source PACS.

Science.gov (United States)

Valeri, Gianluca; Zuccaccia, Matteo; Badaloni, Andrea; Ciriaci, Damiano; La Riccia, Luigi; Mazzoni, Giovanni; Maggi, Stefania; Giovagnoni, Andrea

2015-12-01

To implement a hardware and software system able to perform the major functions of an Open-Source PACS, and to analyze it in a simulated real-world environment. A small home network was implemented, and the Open-Source operating system Ubuntu 11.10 was installed in a laptop containing the Dcm4chee suite with the software devices needed. The Open-Source PACS implemented is compatible with Linux OS, Microsoft OS, and Mac OS X; furthermore, it was used with operating systems that guarantee the operation in portable devices (smartphone, tablet) Android and iOS. An OSS PACS is useful for making tutorials and workshops on post-processing techniques for educational and training purposes.

From PACS to Web-based ePR system with image distribution for enterprise-level filmless healthcare delivery.

Science.gov (United States)

Huang, H K

2011-07-01

The concept of PACS (picture archiving and communication system) was initiated in 1982 during the SPIE medical imaging conference in New Port Beach, CA. Since then PACS has been matured to become an everyday clinical tool for image archiving, communication, display, and review. This paper follows the continuous development of PACS technology including Web-based PACS, PACS and ePR (electronic patient record), enterprise PACS to ePR with image distribution (ID). The concept of large-scale Web-based enterprise PACS and ePR with image distribution is presented along with its implementation, clinical deployment, and operation. The Hong Kong Hospital Authority's (HKHA) integration of its home-grown clinical management system (CMS) with PACS and ePR with image distribution is used as a case study. The current concept and design criteria of the HKHA enterprise integration of the CMS, PACS, and ePR-ID for filmless healthcare delivery are discussed, followed by its work-in-progress and current status.

PACS 2000: quality control using the task allocation chart

Science.gov (United States)

Norton, Gary S.; Romlein, John R.; Lyche, David K.; Richardson, Ronald R., Jr.

2000-05-01

Medical imaging's technological evolution in the next century will continue to include Picture Archive and Communication Systems (PACS) and teleradiology. It is difficult to predict radiology's future in the new millennium with both computed radiography and direct digital capture competing as the primary image acquisition methods for routine radiography. Changes in Computed Axial Tomography (CT) and Magnetic Resonance Imaging (MRI) continue to amaze the healthcare community. No matter how the acquisition, display, and archive functions change, Quality Control (QC) of the radiographic imaging chain will remain an important step in the imaging process. The Task Allocation Chart (TAC) is a tool that can be used in a medical facility's QC process to indicate the testing responsibilities of the image stakeholders and the medical informatics department. The TAC shows a grid of equipment to be serviced, tasks to be performed, and the organization assigned to perform each task. Additionally, skills, tasks, time, and references for each task can be provided. QC of the PACS must be stressed as a primary element of a PACS' implementation. The TAC can be used to clarify responsibilities during warranty and paid maintenance periods. Establishing a TAC a part of a PACS implementation has a positive affect on patient care and clinical acceptance.

PACS and diagnostic imaging service delivery-A UK perspective

International Nuclear Information System (INIS)

Sutton, Laurence N.

2011-01-01

This review sets out the current position with regard to the implementation of PACS throughout the United Kingdom and the impact this has had on improving patient care. In December 2007 England had implemented full hospital-wide PACS in all hospitals: a major achievement in the relatively short time period of three years. The different approaches used by each country of the UK to achieve full national PACS are described in addition to the current issues with the sharing of images and reports across different healthcare organisations with regard to technical solutions, clinical safety and governance. The review gives insight into the changing methods of service delivery to address increasing demand pressures on diagnostic imaging services and how the national PACS implementation, specifically in England, has made a significant contribution to measures to improve efficiencies. The role of Teleradiology is discussed in the context of supporting local patient services rather than undermining them and the concept of cross-healthcare reporting 'Grids' is described. Finally, in the summary it is recognised that the vast wealth of knowledge accumulated during the national implementations has placed the UK in a strong position to facilitate full national data sharing across all healthcare organisations to improve patient care.

Treatment of coal gasification wastewater by membrane bioreactor hybrid powdered activated carbon (MBR–PAC) system.

Science.gov (United States)

Jia, Shengyong; Han, Hongjun; Hou, Baolin; Zhuang, Haifeng; Fang, Fang; Zhao, Qian

2014-12-01

A laboratory-scale membrane bioreactor hybrid powdered activated carbon (MBR–PAC) system was developed to treat coal gasification wastewater to enhance the COD, total phenols (TPh), NH4+ removals and migrate the membrane fouling. Since the MBR–PAC system operated with PAC dosage of 4 g L−1, the maximum removal efficiencies of COD, TPh and NH4+ reached 93%, 99% and 63%, respectively with the corresponding influent concentrations of 2.27 g L−1, 497 mg L−1 and 164 mg N L−1; the PAC extraction efficiencies of COD, TPh and NH4+ were 6%, 3% and 13%, respectively; the transmembrane pressure decreased 34% with PAC after 50 d operation. The results demonstrate that PAC played a key role in the enhancement of biodegradability and mitigation of membrane fouling.

Secure vendor environment (SVE) for PACS

Science.gov (United States)

Honeyman-Buck, Janice; Frost, Meryll

2005-04-01

A Secure Vendor Environment (SVE) was created to protect radiology modalities from network intrusion, worms, viruses, and other forms of damaging attacks. Many vendors do not attempt any form of network security and if an institution demands a non-standard and secure installation, a future system upgrade could and frequently does eliminate any security measures installed during the initial installation. The SVE isolates the vendor equipment behind a virtual firewall on a private network that is invisible to the outside world. All interactions must go though a device containing two network interface cards called an Application Processor that acts as a store-and forward router, performs DICOM repair, proxies modality worklist, and isolates the vendor modalities. A small VPN appliance can open the device temporarily for remote access by vendor engineers. Prior to the routine installation of the SVE, vendor equipment was often attacked by hostile network intruders and viruses or worms, sometimes rendering the equipment unusable until the vendor could reload the system. The resulted in considerable clinical downtime and loss of revenue. Since the relatively low cost SVE solution has routinely been installed with all new equipment, no intrusions have occurred, although our network sniffers and intrusion detectors indicate that we are constantly being scanned for vulnerability. Purpose: To provide a secure network for vendor equipment in a PACS environment while allowing vendor access for upgrades and system repairs. Method: The network administrators at our university believe that network security should be implemented at the machine level rather than relying on a firewall. A firewall solution could conceivably block unwanted intrusion from outside the university network, but would still allow literally thousands of potential network users to get through to the PACS network. All the PACS archive, display and routing systems are individually protected from intrusion, but

Spray Formation of Herschel-Bulkley Fluids using Impinging Jets

Science.gov (United States)

Rodrigues, Neil; Gao, Jian; Chen, Jun; Sojka, Paul E.

2015-11-01

The impinging jet spray formation of two non-Newtonian, shear-thinning, Herschel-Bulkley fluids was investigated in this work. The water-based gelled solutions used were 1.0 wt.-% agar and 1.0 wt.-% kappa carrageenan. A rotational rheometer and a capillary viscometer were used to measure the strain-rate dependency of viscosity and the Herschel-Bulkley Extended (HBE) rheological model was used to characterize the shear-thinning behavior. A generalized HBE jet Reynolds number Rej , gen - HBE was used as the primary parameter to characterize the spray formation. A like-on-like impinging jet doublet was used to produce atomization. Shadowgraphs were captured in the plane of the sheet formed by the two jets using a CCD camera with an Nd:YAG laser beam providing the back-illumination. Typical behavior for impinging jet atomization using Newtonian liquids was not generally observed due to the non-Newtonian, viscous properties of the agar and kappa carrageenan gels. Instead various spray patterns were observed depending on Rej , gen - HBE. Spray characteristics of maximum instability wavelength and sheet breakup length were extracted from the shadowgraphs. Multi-University Research Initiative Grant Number W911NF-08-1-0171.

Image acquisition for the pediatric radiology PACS module

International Nuclear Information System (INIS)

Ho, B.K.; Morioka, C.; Mankovich, N.J.; Stewart, B.; Huang, H.K.

1987-01-01

The prototype PACS module implemented at UCLA's pediatric radiology section has multi-modality access to image data from any of the three types of sources: digital modalities (i.e. CT, MR, and DSA), the Fuji Computed Radiography unit (FCR), and laser film digitizers. An interface unit was built to facilitate real-time data transfer from the FCR to the VAX11/750 which serves as the PACS host computer. The design of the interface unit, methods for linking to digital modalities, and characteristics of two film digitizers are described

THE MASS DISTRIBUTION OF STARLESS AND PROTOSTELLAR CORES IN GOULD BELT CLOUDS

International Nuclear Information System (INIS)

Sadavoy, Sarah I.; Di Francesco, James; Bontemps, Sylvain; Megeath, S. Thomas; Allgaier, Erin; Rebull, Luisa M.; Carey, Sean; McCabe, Caer-Eve; Noriega-Crespo, Alberto; Padgett, Deborah; Gutermuth, Robert; Hora, Joe; Huard, Tracy; Muzerolle, James; Terebey, Susan

2010-01-01

Using data from the SCUBA Legacy Catalogue (850 μm) and Spitzer Space Telescope (3.6-70 μm), we explore dense cores in the Ophiuchus, Taurus, Perseus, Serpens, and Orion molecular clouds. We develop a new method to discriminate submillimeter cores found by Submillimeter Common-User Bolometer Array (SCUBA) as starless or protostellar, using point source photometry from Spitzer wide field surveys. First, we identify infrared sources with red colors associated with embedded young stellar objects (YSOs). Second, we compare the positions of these YSO candidates to our submillimeter cores. With these identifications, we construct new, self-consistent starless and protostellar core mass functions (CMFs) for the five clouds. We find best-fit slopes to the high-mass end of the CMFs of -1.26 ± 0.20, -1.22 ± 0.06, -0.95 ± 0.20, and -1.67 ± 0.72 for Ophiuchus, Taurus, Perseus, and Orion, respectively. Broadly, these slopes are each consistent with the -1.35 power-law slope of the Salpeter initial mass function at higher masses, but suggest some differences. We examine a variety of trends between these CMF shapes and their parent cloud properties, potentially finding a correlation between the high-mass slope and core temperature. We also find a trend between core mass and effective size, but we are very limited by sensitivity. We make similar comparisons between core mass and size with visual extinction (for A V ≥ 3) and find no obvious trends. We also predict the numbers and mass distributions of cores that future surveys with SCUBA-2 may detect in each of these clouds.

Resolving the structure of the Galactic foreground using Herschel measurements and the Kriging technique

Science.gov (United States)

Pinter, S.; Bagoly, Z.; Balázs, L. G.; Horvath, I.; Racz, I. I.; Zahorecz, S.; Tóth, L. V.

2018-05-01

Investigating the distant extragalactic Universe requires a subtraction of the Galactic foreground. One of the major difficulties deriving the fine structure of the galactic foreground is the embedded foreground and background point sources appearing in the given fields. It is especially so in the infrared. We report our study subtracting point sources from Herschel images with Kriging, an interpolation method where the interpolated values are modelled by a Gaussian process governed by prior covariances. Using the Kriging method on Herschel multi-wavelength observations the structure of the Galactic foreground can be studied with much higher resolution than previously, leading to a better foreground subtraction at the end.

Compact binary merger and kilonova: outflows from remnant disc

Science.gov (United States)

Yi, Tuan; Gu, Wei-Min; Liu, Tong; Kumar, Rajiv; Mu, Hui-Jun; Song, Cui-Ying

2018-05-01

Outflows launched from a remnant disc of compact binary merger may have essential contribution to the kilonova emission. Numerical calculations are conducted in this work to study the structure of accretion flows and outflows. By the incorporation of limited-energy advection in the hyper-accretion discs, outflows occur naturally from accretion flows due to imbalance between the viscous heating and the sum of the advective and radiative cooling. Following this spirit, we revisit the properties of the merger outflow ejecta. Our results show that around 10-3 ˜ 10-1 M⊙ of the disc mass can be launched as powerful outflows. The amount of unbound mass varies with the disc mass and the viscosity. The outflow-contributed peak luminosity is around 1040 ˜ 1041 erg s-1. Such a scenario can account for the observed kilonovae associated with short gamma-ray bursts, including the recent event AT2017gfo (GW170817).

Character and dynamics of the Red Sea and Persian Gulf outflows

Science.gov (United States)

Bower, Amy S.; Hunt, Heather D.; Price, James F.

2000-03-01

Historical hydrographic data and a numerical plume model are used to investigate the initial transformation, dynamics, and spreading pathways of Red Sea and Persian Gulf outflow waters where they enter the Indian Ocean. The annual mean transport of these outflows is relatively small (outflows in that they flow over very shallow sills (depth Red Sea outflow exhibits strong seasonal variability in transport. The four main results of this study are as follows. First, on the basis of observed temperature-salinity (T-S) characteristics of the outflow source and product waters we estimate that the Red Sea and Persian Gulf outflows are diluted by factors of ˜2.5 and 4, respectively, as they descend from sill depth to their depth of neutral buoyancy. The high-dilution factor for the Persian Gulf outflow results from the combined effects of large initial density difference between the outflow source water and oceanic water and low outflow transport. Second, the combination of low latitude and low outflow transport (and associated low outflow thickness) results in Ekman numbers for both outflows that are O(1). This indicates that they should be thought of as frictional density currents modified by rotation rather than geostrophic density currents modified by friction. Third, different mixing histories along the two channels that direct Red Sea outflow water into the open ocean result in product waters with significantly different densities, which probably contributes to the multilayered structure of the Red Sea product waters. In both outflows, seasonal variations in source water and oceanic properties have some effect on the T-S of the product waters, but they have only a minor impact on equilibrium depth. Fourth, product waters from both outflows are advected away from the sill region in narrow boundary currents, at least during part of the year. At other times, the product water appears more in isolated patches.

Cerebral venous outflow and cerebrospinal fluid dynamics

Directory of Open Access Journals (Sweden)

Clive B. Beggs

2014-12-01

Full Text Available In this review, the impact of restricted cerebral venous outflow on the biomechanics of the intracranial fluid system is investigated. The cerebral venous drainage system is often viewed simply as a series of collecting vessels channeling blood back to the heart. However there is growing evidence that it plays an important role in regulating the intracranial fluid system. In particular, there appears to be a link between increased cerebrospinal fluid (CSF pulsatility in the Aqueduct of Sylvius and constricted venous outflow. Constricted venous outflow also appears to inhibit absorption of CSF into the superior sagittal sinus. The compliance of the cortical bridging veins appears to be critical to the behaviour of the intracranial fluid system, with abnormalities at this location implicated in normal pressure hydrocephalus. The compliance associated with these vessels appears to be functional in nature and dependent on the free egress of blood out of the cranium via the extracranial venous drainage pathways. Because constricted venous outflow appears to be linked with increased aqueductal CSF pulsatility, it suggests that inhibited venous blood outflow may be altering the compliance of the cortical bridging veins.

ALMA OBSERVATIONS OF THE HH 46/47 MOLECULAR OUTFLOW

International Nuclear Information System (INIS)

Arce, Héctor G.; Mardones, Diego; Garay, Guido; Corder, Stuartt A.; Noriega-Crespo, Alberto; Raga, Alejandro C.

2013-01-01

The morphology, kinematics, and entrainment mechanism of the HH 46/47 molecular outflow were studied using new ALMA Cycle 0 observations. Results show that the blue and red lobes are strikingly different. We argue that these differences are partly due to contrasting ambient densities that result in different wind components having a distinct effect on the entrained gas in each lobe. A 29 point mosaic, covering the two lobes at an angular resolution of about 3'', detected outflow emission at much higher velocities than previous observations, resulting in significantly higher estimates of the outflow momentum and kinetic energy than previous studies of this source, using the CO(1-0) line. The morphology and the kinematics of the gas in the blue lobe are consistent with models of outflow entrainment by a wide-angle wind, and a simple model describes the observed structures in the position-velocity diagram and the velocity-integrated intensity maps. The red lobe exhibits a more complex structure, and there is evidence that this lobe is entrained by a wide-angle wind and a collimated episodic wind. Three major clumps along the outflow axis show velocity distribution consistent with prompt entrainment by different bow shocks formed by periodic mass ejection episodes which take place every few hundred years. Position-velocity cuts perpendicular to the outflow cavity show gradients where the velocity increases toward the outflow axis, inconsistent with outflow rotation. Additionally, we find evidence for the existence of a small outflow driven by a binary companion

Relativistic Outflows from ADAFs

Science.gov (United States)

Becker, Peter; Subramanian, Prasad; Kazanas, Demosthenes

2001-04-01

Advection-dominated accretion flows (ADAFs) have a positive Bernoulli parameter, and are therefore gravitationally bound. The Newtonian ADAF model has been generalized recently to obtain the ADIOS model that includes outflows of energy and angular momentum, thereby allowing accretion to proceed self-consistently. However, the utilization of a Newtonian gravitational potential limits the ability of this model to describe the inner region of the disk, where any relativistic outflows are likely to originate. In this paper we modify the ADIOS scenario to incorporate a seudo - Newtonian potential, which approximates the effects of general relativity. The analysis yields a unique, self - similar solution for the structure of the coupled disk/wind system. Interesting features of the new solution include the relativistic character of the outflow in the vicinity of the radius of marginal stability, which represents the inner edge of the quasi-Keplerian disk in our model. Our self - similar model may therefore help to explain the origin of relativistic jets in active galaxies. At large distances the radial dependence of the accretion rate approachs the unique form dot M ∝ r^1/2, with an associated density variation given by ρ ∝ r-1. This density variation agrees with that implied by the dependence of the X-ray hard time lags on the Fourier frequency for a number of accreting galactic black hole candidates. While intriguing, the results of our self-similar model need to be confirmed in the future by incorporating a detailed physical description of the energization mechanism that drives the outflow, which is likely to be powered by the shear of the underlying accretion disk.

Simbol-X: Synergies with JWST, ALMA and Herschel

Science.gov (United States)

Maiolino, R.

2009-05-01

I discuss the synergies between Simbol-X and three among the major astronomical facilities that, in the next decade, will be operative in the infrared-millimeter spectral range, namely JWST, Herschel and ALMA. I first provide a brief overview of the main features and observing capabilities offered by these facilities. Then I will discuss a few research fields (mostly extragalactic) that will geatly benefit of the joint exploitation of Simbol-X and these IR-mm observatories.

Density diagnostics of ionized outflows in active galacitc nuclei

Science.gov (United States)

Mao, J.; Kaastra, J.; Mehdipour, M.; Raassen, T.; Gu, L.

2017-10-01

Ionized outflows in Active Galactic Nuclei are thought to influence their nuclear and local galactic environment. However, the distance of outflows with respect to the central engine is poorly constrained, which limits our understanding of the kinetic power by the outflows. Therefore, the impact of AGN outflows on their host galaxies is uncertain. Given the density of the outflows, their distance can be immediately obtained by the definition of the ionization parameter. Here we carry out a theoretical study of density diagnostics of AGN outflows using absorption lines from metastable levels in Be-like to F-like ions. With the new self-consistent photoionization model (PION) in the SPEX code, we are able to calculate ground and metastable level populations. This enable us to determine under what physical conditions these levels are significantly populated. We then identify characteristic transitions from these metastable levels in the X-ray band. Firm detections of absorption lines from such metastable levels are challenging for current grating instruments. The next generation of spectrometers like X-IFU onboard Athena will certainly identify the presence/absence of these density- sensitive absorption lines, thus tightly constraining the location and the kinetic power of AGN outflows.

PACS infrastructure supporting e-learning

Energy Technology Data Exchange (ETDEWEB)

Mildenberger, Peter, E-mail: milden@radiologie.klinik.uni-mainz.de [University Medicine Mainz, Johannes Gutenberg-University Mainz, Langenbeckstr 1, Mainz (Germany); Brueggemann, Kerstin; Roesner, Freya; Koch, Katja; Ahlers, Christopher [University Medicine Mainz, Johannes Gutenberg-University Mainz, Langenbeckstr 1, Mainz (Germany)

2011-05-15

Digital imaging is becoming predominant in radiology. This has implications for teaching support, because conventional film-based concepts are now obsolete. The IHE Teaching File and Clinical Study Export (TCE) profile provides an excellent platform to enhance PACS infrastructure with educational functionality. This can be supplemented with dedicated e-learning tools.

PACS infrastructure supporting e-learning

International Nuclear Information System (INIS)

Mildenberger, Peter; Brueggemann, Kerstin; Roesner, Freya; Koch, Katja; Ahlers, Christopher

2011-01-01

Digital imaging is becoming predominant in radiology. This has implications for teaching support, because conventional film-based concepts are now obsolete. The IHE Teaching File and Clinical Study Export (TCE) profile provides an excellent platform to enhance PACS infrastructure with educational functionality. This can be supplemented with dedicated e-learning tools.

A NOVEL TECHNIQUE TO IMPROVE PHOTOMETRY IN CONFUSED IMAGES USING GRAPHS AND BAYESIAN PRIORS

International Nuclear Information System (INIS)

Safarzadeh, Mohammadtaher; Ferguson, Henry C.; Lu, Yu; Inami, Hanae; Somerville, Rachel S.

2015-01-01

We present a new technique for overcoming confusion noise in deep far-infrared Herschel space telescope images making use of prior information from shorter λ < 2 μm wavelengths. For the deepest images obtained by Herschel, the flux limit due to source confusion is about a factor of three brighter than the flux limit due to instrumental noise and (smooth) sky background. We have investigated the possibility of de-confusing simulated Herschel PACS 160 μm images by using strong Bayesian priors on the positions and weak priors on the flux of sources. We find the blended sources and group them together and simultaneously fit their fluxes. We derive the posterior probability distribution function of fluxes subject to these priors through Monte Carlo Markov Chain (MCMC) sampling by fitting the image. Assuming we can predict the FIR flux of sources based on the ultraviolet-optical part of their SEDs to within an order of magnitude, the simulations show that we can obtain reliable fluxes and uncertainties at least a factor of three fainter than the confusion noise limit of 3σ c = 2.7 mJy in our simulated PACS-160 image. This technique could in principle be used to mitigate the effects of source confusion in any situation where one has prior information of positions and plausible fluxes of blended sources. For Herschel, application of this technique will improve our ability to constrain the dust content in normal galaxies at high redshift

THE SPECTRAL ENERGY DISTRIBUTIONS AND INFRARED LUMINOSITIES OF z ≈ 2 DUST-OBSCURED GALAXIES FROM Herschel AND Spitzer

International Nuclear Information System (INIS)

Melbourne, J.; Soifer, B. T.; Desai, Vandana; Armus, Lee; Pope, Alexandra; Alberts, Stacey; Dey, Arjun; Jannuzi, B. T.; Bussmann, R. S.

2012-01-01

Dust-obscured galaxies (DOGs) are a subset of high-redshift (z ≈ 2) optically-faint ultra-luminous infrared galaxies (ULIRGs, e.g., L IR > 10 12 L ☉ ). We present new far-infrared photometry, at 250, 350, and 500 μm (observed-frame), from the Herschel Space Telescope for a large sample of 113 DOGs with spectroscopically measured redshifts. Approximately 60% of the sample are detected in the far-IR. The Herschel photometry allows the first robust determinations of the total infrared luminosities of a large sample of DOGs, confirming their high IR luminosities, which range from 10 11.6 L ☉ IR (8-1000 μm) 13.6 L ☉ . 90% of the Herschel-detected DOGs in this sample are ULIRGs and 30% have L IR > 10 13 L ☉ . The rest-frame near-IR (1-3 μm) spectral energy distributions (SEDs) of the Herschel-detected DOGs are predictors of their SEDs at longer wavelengths. DOGs with 'power-law' SEDs in the rest-frame near-IR show observed-frame 250/24 μm flux density ratios similar to the QSO-like local ULIRG, Mrk 231. DOGs with a stellar 'bump' in their rest-frame near-IR show observed-frame 250/24 μm flux density ratios similar to local star-bursting ULIRGs like NGC 6240. None show 250/24 μm flux density ratios similar to extreme local ULIRG, Arp 220; though three show 350/24 μm flux density ratios similar to Arp 220. For the Herschel-detected DOGs, accurate estimates (within ∼25%) of total IR luminosity can be predicted from their rest-frame mid-IR data alone (e.g., from Spitzer observed-frame 24 μm luminosities). Herschel-detected DOGs tend to have a high ratio of infrared luminosity to rest-frame 8 μm luminosity (the IR8 = L IR (8-1000 μm)/νL ν (8 μm) parameter of Elbaz et al.). Instead of lying on the z = 1-2 'infrared main sequence' of star-forming galaxies (like typical LIRGs and ULIRGs at those epochs) the DOGs, especially large fractions of the bump sources, tend to lie in the starburst sequence. While, Herschel-detected DOGs are similar to scaled up

A demanding web-based PACS supported by web services technology

Science.gov (United States)

Costa, Carlos M. A.; Silva, Augusto; Oliveira, José L.; Ribeiro, Vasco G.; Ribeiro, José

2006-03-01

During the last years, the ubiquity of web interfaces have pushed practically all PACS suppliers to develop client applications in which clinical practitioners can receive and analyze medical images, using conventional personal computers and Web browsers. However, due to security and performance issues, the utilization of these software packages has been restricted to Intranets. Paradigmatically, one of the most important advantages of digital image systems is to simplify the widespread sharing and remote access of medical data between healthcare institutions. This paper analyses the traditional PACS drawbacks that contribute to their reduced usage in the Internet and describes a PACS based on Web Services technology that supports a customized DICOM encoding syntax and a specific compression scheme providing all historical patient data in a unique Web interface.

ARE PROTOPLANETARY DISKS BORN WITH VORTICES? ROSSBY WAVE INSTABILITY DRIVEN BY PROTOSTELLAR INFALL

Energy Technology Data Exchange (ETDEWEB)

Bae, Jaehan; Hartmann, Lee [Deptartment of Astronomy, University of Michigan, 1085 S. University Ave., Ann Arbor, MI 48109 (United States); Zhu, Zhaohuan, E-mail: jaehbae@umich.edu, E-mail: lhartm@umich.edu, E-mail: zhuzh@astro.princeton.edu [Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Peyton Hall, Princeton, NJ 08544 (United States)

2015-05-20

We carry out two-fluid, two-dimensional global hydrodynamic simulations to test whether protostellar infall can trigger the Rossby wave instability (RWI) in protoplanetry disks. Our results show that infall can trigger the RWI and generate vortices near the outer edge of the mass landing on the disk (i.e., centrifugal radius). We find that the RWI is triggered under a variety of conditions, although the details depend on the disk parameters and the infall pattern. The common key feature of triggering the RWI is the steep radial gradient of the azimuthal velocity induced by the local increase in density at the outer edge of the infall region. Vortices form when the instability enters the nonlinear regime. In our standard model where self-gravity is neglected, vortices merge together to a single vortex within ∼20 local orbital times, and the merged vortex survives for the remaining duration of the calculation (>170 local orbital times). The vortex takes part in outward angular momentum transport, with a Reynolds stress of ≲10{sup −2}. Our two-fluid calculations show that vortices efficiently trap dust particles with stopping times of the order of the orbital time, locally enhancing the dust to gas ratio for particles of the appropriate size by a factor of ∼40 in our standard model. When self-gravity is considered, however, vortices tend to be impeded from merging and may eventually dissipate. We conclude it may well be that protoplanetary disks have favorable conditions for vortex formation during the protostellar infall phase, which might enhance early planetary core formation.

ARE PROTOPLANETARY DISKS BORN WITH VORTICES? ROSSBY WAVE INSTABILITY DRIVEN BY PROTOSTELLAR INFALL

International Nuclear Information System (INIS)

Bae, Jaehan; Hartmann, Lee; Zhu, Zhaohuan

2015-01-01

We carry out two-fluid, two-dimensional global hydrodynamic simulations to test whether protostellar infall can trigger the Rossby wave instability (RWI) in protoplanetry disks. Our results show that infall can trigger the RWI and generate vortices near the outer edge of the mass landing on the disk (i.e., centrifugal radius). We find that the RWI is triggered under a variety of conditions, although the details depend on the disk parameters and the infall pattern. The common key feature of triggering the RWI is the steep radial gradient of the azimuthal velocity induced by the local increase in density at the outer edge of the infall region. Vortices form when the instability enters the nonlinear regime. In our standard model where self-gravity is neglected, vortices merge together to a single vortex within ∼20 local orbital times, and the merged vortex survives for the remaining duration of the calculation (>170 local orbital times). The vortex takes part in outward angular momentum transport, with a Reynolds stress of ≲10 −2 . Our two-fluid calculations show that vortices efficiently trap dust particles with stopping times of the order of the orbital time, locally enhancing the dust to gas ratio for particles of the appropriate size by a factor of ∼40 in our standard model. When self-gravity is considered, however, vortices tend to be impeded from merging and may eventually dissipate. We conclude it may well be that protoplanetary disks have favorable conditions for vortex formation during the protostellar infall phase, which might enhance early planetary core formation

Water in low-mass star-forming regions with Herschel

DEFF Research Database (Denmark)

Kristensen, L. E.; Visser, R.; Van Dishoeck, E. F.

2010-01-01

"Water In Star-forming regions with Herschel" (WISH) is a key programme dedicated to studying the role of water and related species during the star-formation process and constraining the physical and chemical properties of young stellar objects. The Heterodyne Instrument for the Far-Infrared (HIF...

Characterization of molecular outflows in the substellar domain

International Nuclear Information System (INIS)

Phan-Bao, Ngoc; Dang-Duc, Cuong; Lee, Chin-Fei; Ho, Paul T. P.; Li, Di

2014-01-01

We report here our latest search for molecular outflows from young brown dwarfs and very low-mass stars in nearby star-forming regions. We have observed three sources in Taurus with the Submillimeter Array and the Combined Array for Research in Millimeter-wave Astronomy at 230 GHz frequency to search for CO J = 2 → 1 outflows. We obtain a tentative detection of a redshifted and extended gas lobe at about 10 arcsec from the source GM Tau, a young brown dwarf in Taurus with an estimated mass of 73 M J , which is right below the hydrogen-burning limit. No blueshifted emission around the brown dwarf position is detected. The redshifted gas lobe that is elongated in the northeast direction suggests a possible bipolar outflow from the source with a position angle of about 36°. Assuming that the redshifted emission is outflow emission from GM Tau, we then estimate a molecular outflow mass in the range from 1.9 × 10 –6 M ☉ to 2.9 × 10 –5 M ☉ and an outflow mass-loss rate from 2.7 × 10 –9 M ☉ yr –1 to 4.1 × 10 –8 M ☉ yr –1 . These values are comparable to those we have observed in the young brown dwarf ISO-Oph 102 of 60 M J in ρ Ophiuchi and the very low-mass star MHO 5 of 90 M J in Taurus. Our results suggest that the outflow process in very low-mass objects is episodic with a duration of a few thousand years and the outflow rate of active episodes does not significantly change for different stages of the formation process of very low-mass objects. This may provide us with important implications that clarify the formation process of brown dwarfs.

Investment alternative: the status quo or PACS?

Science.gov (United States)

Vanden Brink, John A.; Cywinski, Jozef K.

1990-08-01

While the cost of Picture Archiving and Communication Systems (PACS) can be substantial, the cost of continuing with present manual methods may become prohibitive in growing departments as the need for additional space and personnel (both technical and professional) to meet the increasing requirements for all image management activities continues to grow. This will occur simultaneously with increasing pressures on problems of the present system, i.e., lost films, lost revenues, delayed reporting and longer diagnostic cycle times. Present methods of image archiving communication and management i.e. the relationship of procedure volume to VFE requirements for professional and technical personnel, costs of film, film storage space, and other performance factors are analyzed based on the database created by the Technology Marketing Group (TMG) computerized cost analysis model applied to over 50 US hospitals. Also, the model is used to provide the projected cost of present methods of film management for an average US 400 +bed hospital based on ten year growth rate assumptions. TMG PACS Tracking data provides confirmation of staffmg pattern correlation to procedure volume. The data presented in the paper provides a basis for comparing the investment in maintaining the status quo to an investment in PACS.

Herschel/SPIRE observations of the dusty disk of NGC 4244

NARCIS (Netherlands)

Holwerda, B. W.; Bianchi, S.; Boker, T.; Radburn-Smith, D.; de Jong, R. S.; Baes, M.; van der Kruit, P. C.; Xilouris, M.; Gordon, K. D.; Dalcanton, J. J.

We present Herschel/SPIRE images at 250, 350, and 500 mu m of NGC 4244, a typical low-mass, disk-only and edge-on spiral galaxy. The dust disk is clumpy and shows signs of truncation at the break radius of the stellar disk. This disk coincides with the densest part of the Hi disk. We compare the

The Mass Outflow Rate of the Milky Way

Science.gov (United States)

Fox, Andrew

2017-08-01

The balance between gaseous inflow and outflow regulates star formation in spiral galaxies. This paradigm can be tested in the Milky Way, but whereas the star formation rate and inflow rate have both been measured, the outflow rate has not. We propose an archival COS program to determine the Galactic outflow rate in cool gas ( 10^4 K) by surveying UV absorption line high-velocity clouds (HVCs). This project will make use of the newly updated Hubble Spectroscopic Legacy Archive, which contains a uniformly reduced sample of 233 COS G130M spectra of background AGN. The outflow rate will be determined by (1) searching for redshifted HVCs; (2) modeling the clouds with photoionization simulations to determine their masses and physical properties; (3) combining the cloud masses with their velocities and distances. We will measure how the outflow is distributed spatially across the sky, calculate its mass loading factor, and compare the line profiles to synthetic spectra extracted from new hydrodynamic simulations. The distribution of HVC velocities will inform us what fraction of the outflowing clouds will escape the halo and what fraction will circulate back to the disk, to better understand how and where gas enters and exits the Milky Way.

XDS-I Gateway Development for HIE Connectivity with Legacy PACS at Gil Hospital.

Science.gov (United States)

Simalango, Mikael Fernandus; Kim, Youngchul; Seo, Young Tae; Choi, Young Hwan; Cho, Yong Kyun

2013-12-01

The ability to support healthcare document sharing is imperative in a health information exchange (HIE). Sharing imaging documents or images, however, can be challenging, especially when they are stored in a picture archiving and communication system (PACS) archive that does not support document sharing via standard HIE protocols. This research proposes a standard-compliant imaging gateway that enables connectivity between a legacy PACS and the entire HIE. Investigation of the PACS solutions used at Gil Hospital was conducted. An imaging gateway application was then developed using a Java technology stack. Imaging document sharing capability enabled by the gateway was tested by integrating it into Gil Hospital's order communication system and its HIE infrastructure. The gateway can acquire radiology images from a PACS storage system, provide and register the images to Gil Hospital's HIE for document sharing purposes, and make the images retrievable by a cross-enterprise document sharing document viewer. Development of an imaging gateway that mediates communication between a PACS and an HIE can be considered a viable option when the PACS does not support the standard protocol for cross-enterprise document sharing for imaging. Furthermore, the availability of common HIE standards expedites the development and integration of the imaging gateway with an HIE.

MAGNETIC BRAKING AND PROTOSTELLAR DISK FORMATION: AMBIPOLAR DIFFUSION

International Nuclear Information System (INIS)

Mellon, Richard R.; Li Zhiyun

2009-01-01

It is established that the formation of rotationally supported disks during the main accretion phase of star formation is suppressed by a moderately strong magnetic field in the ideal MHD limit. Nonideal MHD effects are expected to weaken the magnetic braking, perhaps allowing the disk to reappear. We concentrate on one such effect, ambipolar diffusion, which enables the field lines to slip relative to the bulk neutral matter. We find that the slippage does not sufficiently weaken the braking to allow rotationally supported disks to form for realistic levels of cloud magnetization and cosmic ray ionization rate; in some cases, the magnetic braking is even enhanced. Only in dense cores with both exceptionally weak fields and unreasonably low ionization rate do such disks start to form in our simulations. We conclude that additional processes, such as Ohmic dissipation or Hall effect, are needed to enable disk formation. Alternatively, the disk may form at late times when the massive envelope that anchors the magnetic brake is dissipated, perhaps by a protostellar wind.

Completion and Testing of PACS SWIR Channel

Data.gov (United States)

National Aeronautics and Space Administration — PACS SWIR has important technological innovations that will be necessary to meet the mission requirements for wide FOV, hyperangle capability, high polarimetric...

DISCOVERY OF RELATIVISTIC OUTFLOW IN THE SEYFERT GALAXY Ark 564

International Nuclear Information System (INIS)

Gupta, A.; Mathur, S.; Krongold, Y.; Nicastro, F.

2013-01-01

We present Chandra High Energy Transmission Grating Spectra of the narrow-line Seyfert-1 galaxy Ark 564. The spectrum shows numerous absorption lines which are well modeled with low-velocity outflow components usually observed in Seyfert galaxies. There are, however, some residual absorption lines which are not accounted for by low-velocity outflows. Here, we present identifications of the strongest lines as Kα transitions of O VII (two lines) and O VI at outflow velocities of ∼0.1c. These lines are detected at 6.9σ, 6.2σ, and 4.7σ, respectively, and cannot be due to chance statistical fluctuations. Photoionization models with ultra-high velocity components improve the spectral fit significantly, providing further support for the presence of relativistic outflow in this source. Without knowing the location of the absorber, its mass and energy outflow rates cannot be well constrained; we find E-dot (outflow)/L bol lower limit of ≥0.006% assuming a bi-conical wind geometry. This is the first time that absorption lines with ultra-high velocities are unambiguously detected in the soft X-ray band. The presence of outflows with relativistic velocities in active galactic nuclei (AGNs) with Seyfert-type luminosities is hard to understand and provides valuable constraints to models of AGN outflows. Radiation pressure is unlikely to be the driving mechanism for such outflows and magnetohydrodynamic may be involved

A Comprehensive Study of ULIRGs in the Herschel Very Wide Field Surveys

Science.gov (United States)

Yan, Haojing

Extreme starbursting galaxies exist at all redshifts, and most of them are so heavily obscured by dust that they are Ultra-Luminous InfraRed Galaxies (ULIRGs) while being faint in optical to near-IR. The latest example is at record-high z=6.337, approaching the end of the reionization. There have been numerous suggestions that understanding ULIRG is critical in constructing a comprehensive picture of galaxy formation history. These range from the hypothesis three decades ago that the ULIRG phase is the prelude to QSO and large ellipticals, to the recent tentative evidence that ULIRG could make a large (if not dominant) contribution to the global star formation rate density (GSFRD) at z>1. However, the exact nature of ULIRG and their role in galaxy assembly still remain illusive, largely due to the limited sample size and the severe source confusion problem in the far-IR (FIR). The very wide field surveys by Herschel have provided the best opportunity to date to systematically study ULIRG beyond the local universe, most importantly because of their wide coverage and high sensitivity to probe large volumes to high redshifts and the multiple FIR bands that allow for direct measurement of the IR luminosities. We propose to construct the largest possible ULIRG sample in these fields at all redshifts, and to study the evolution of ULIRGs. We will concentrate on the HerMES, the H-ATLAS and the HerS programs whose data are already public. While the confusion problem still persists in these Herschel data, we have demonstrated that it is possible to directly use the position priors from optical images to decompose the candidate contributors to a given Herschel source if its S/N suffices (Yan et al. 2014). This is a significant improvement over previous studies where higher-resolution mid-IR (mostly Spitzer MIPS 24-micron) data had to be used as the proxies to the FIR source locations, because (1) such proxy images also suffer from the blending problem in the first place and

Influence map baserad Ms. Pac-Man och Ghost Kontroller

OpenAIRE

Svensson, Johan

2012-01-01

This thesis will cover the use oftheinfluence map technique applied to the retro game Ms. Pac-Man. A game thatis easy to learn but hard to master. The Ms. Pac-Man controller is implemented with five main parameters that alters the behaviour of the controller while the Ghost controller have three parameters. The experimental results of the controllers is explored to using the alterations of the parameters to find its peak of performance. The conclusion from using the influence map for this gam...

Superfine powdered activated carbon (S-PAC) coatings on microfiltration membranes: Effects of milling time on contaminant removal and flux.

Science.gov (United States)

Amaral, Pauline; Partlan, Erin; Li, Mengfei; Lapolli, Flavio; Mefford, O Thompson; Karanfil, Tanju; Ladner, David A

2016-09-01

In microfiltration processes for drinking water treatment, one method of removing trace contaminants is to add powdered activated carbon (PAC). Recently, a version of PAC called superfine PAC (S-PAC) has been under development. S-PAC has a smaller particle size and thus faster adsorption kinetics than conventionally sized PAC. Membrane coating performance of various S-PAC samples was evaluated by measuring adsorption of atrazine, a model micropollutant. S-PACs were created in-house from PACs of three different materials: coal, wood, and coconut shell. Milling time was varied to produce S-PACs pulverized with different amounts of energy. These had different particles sizes, but other properties (e.g. oxygen content), also differed. In pure water the coal based S-PACs showed superior atrazine adsorption; all milled carbons had over 90% removal while the PAC had only 45% removal. With addition of calcium and/or NOM, removal rates decreased, but milled carbons still removed more atrazine than PAC. Oxygen content and specific external surface area (both of which increased with longer milling times) were the most significant predictors of atrazine removal. S-PAC coatings resulted in loss of filtration flux compared to an uncoated membrane and smaller particles caused more flux decline than larger particles; however, the data suggest that NOM fouling is still more of a concern than S-PAC fouling. The addition of calcium improved the flux, especially for the longer-milled carbons. Overall the data show that when milling S-PAC with different levels of energy there is a tradeoff: smaller particles adsorb contaminants better, but cause greater flux decline. Fortunately, an acceptable balance may be possible; for example, in these experiments the coal-based S-PAC after 30 min of milling achieved a fairly high atrazine removal (overall 80%) with a fairly low flux reduction (under 30%) even in the presence of NOM. This suggests that relatively short duration (low energy

Picture archiving and communication systems (PACS) in clinical practice

International Nuclear Information System (INIS)

Carreno Pedemonte, J.C.; Piqueras Pardellans, J.; Lucaya Layret, J.

1994-01-01

Picture archiving and communication systems (PACS) were developed as a technological response to the complex management of the growing amount of information generated by the different diagnostic imaging methods. This article documents the process of the progressive implementation, starting in January 1991, of the first complete PACS installed in our country. The system installed in our center is composed of acquisition modules for all the imaging methods (computed radiography, ultrasound, computed tomography, digital fluoroscopy and magnetic resonance), a central processing unit, an automatic optical disk for storage and a network of image viewing and diagnostic stations. The preliminary results obtained with its implementation demonstrate that PACS provide a series of functional advantages, especially at the image storage and display levels. In spite of these conveniences, the present high costs of acquisition and maintenance, together with certain technical problems as a result of its complexity, will signify that its generalized application for all imaging methods will not become a reality at most centers in the near future

Revealing H₂D⁺ depletion and compact structure in starless and protostellar cores with ALMA

DEFF Research Database (Denmark)

Friesen, R. K.; Di Francesco, J.; Bourke, T. L.

2014-01-01

We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of the submillimeter dust continuum and H2D+ 110-111 emission toward two evolved, potentially protostellar cores within the Ophiuchus molecular cloud, Oph A SM1 and SM1N. The data reveal small-scale condensations within b...

Candidate high-z protoclusters among the Planck compact sources, as revealed by Herschel-SPIRE

Science.gov (United States)

Greenslade, J.; Clements, D. L.; Cheng, T.; De Zotti, G.; Scott, D.; Valiante, E.; Eales, S.; Bremer, M. N.; Dannerbauer, H.; Birkinshaw, M.; Farrah, D.; Harrison, D. L.; Michałowski, M. J.; Valtchanov, I.; Oteo, I.; Baes, M.; Cooray, A.; Negrello, M.; Wang, L.; van der Werf, P.; Dunne, L.; Dye, S.

2018-05-01

By determining the nature of all the Planck compact sources within 808.4 deg2 of large Herschel surveys, we have identified 27 candidate protoclusters of dusty star-forming galaxies (DSFGs) that are at least 3σ overdense in either 250, 350, or 500 μm sources. We find roughly half of all the Planck compact sources are resolved by Herschel into multiple discrete objects, with the other half remaining unresolved by Herschel. We find a significant difference between versions of the Planck catalogues, with earlier releases hosting a larger fraction of candidate protoclusters and Galactic cirrus than later releases, which we ascribe to a difference in the filters used in the creation of the three catalogues. We find a surface density of DSFG candidate protoclusters of (3.3 ± 0.7) × 10-2 sources deg-2, in good agreement with previous similar studies. We find that a Planck colour selection of S857/S545 1. Our candidate protoclusters are a factor of 5 times brighter at 353 GHz than expected from simulations, even in the most conservative estimates. Further observations are needed to confirm whether these candidate protoclusters are physical clusters, multiple protoclusters along the line of sight, or chance alignments of unassociated sources.

PACS: Picture Archiving and Communication Systems

International Nuclear Information System (INIS)

Gell, G.; Schneider, G.H.; Becker, M.; Wiltgen, M.

1988-01-01

A growing number of medical imaging modalities produces images that are initially calculated and stored as digital information in a computer. For diagnosis, archiving and communication a hardcopy (usually on X-ray film) is produced from these data. It is estimated that in 1995 about 80% of all imaging procedures will generate digital images. This trend leads to the development of systems, where the X-ray film is not only replaced in his function as a radiation detector, but also in his other functions as the medium for image presentation, image communication and image archiving. In short, one wants a completely digital picture archiving and communication system (PACS). The rationale behind PACS efforts is to achieve better functionality and to save costs, mainly by reducing the consumption of expensive X-ray films and the need for storage space for film archives. 7 refs., 2 figs. (Author)

Integration of radiology and hospital information systems (RIS, HIS) with PACS

International Nuclear Information System (INIS)

Mosser, H.; Urban, M.; Hruby, W.; Duerr, M.; Rueger, W.

1992-01-01

PACS development has now reached a stage where it can clearly be stated that the technology for storage, networking and display in a fully digital environment is available. This is reflected by an already large and rapidly increasing number of PACS installations in USA, Western Europe and Japan. Such installations consist of a great variety of information systems, more or less interconnected, like PACS, HIS, RIS and other departmental systems, differing in both hardware and software. Various data -even if they only concern one person- are stored in different systems distributed in the hospital. The integration of all digital systems into a functional unit is determined by the radiologist's need of quick access to all relevant information regardless where it is stored. The interconnection and functional integration of all digital systems in the hospital determine the clinical benefits of PACS. This paper describes the radiologist's requirements concerning this integration, and presents some realistic solutions such as the Siemens ISI (Information System Interface), and a mobile viewing station for the wards (visitBox). (author). 9 refs., 4 figs

Development and practice for a PACS-based interactive teaching model for CT image

International Nuclear Information System (INIS)

Tian Junzhang; Jiang Guihua; Zheng Liyin; Wang Ling; Wenhua; Liang Lianbao

2002-01-01

Objective: To explore the interactive teaching model for CT imaging based on PACS, and provide the clinician and young radiologist with continued medical education. Methods: 100 M trunk net was adopted in PACS and 10 M was exchanged on desktop. Teaching model was installed in browse and diagnosis workstation. Teaching contents were classified according to region and managed according to branch model. Text data derived from authoritative textbooks, monograph, and periodicals. Imaging data derived from cases proved by pathology and clinic. The data were obtained through digital camera and scanner or from PACS. After edited and transformed into standard digital image through DICOM server, they were saved in HD of PACS image server with file form. Results: Teaching model for CT imaging provided kinds of cases of CT sign, clinic characteristics, pathology and distinguishing diagnosis. Normal section anatomy, typical image, and its notation could be browsed real time. Teaching model for CT imaging could provide reference to teaching, diagnosis and report. Conclusion: PACS-based teaching model for CT imaging could provide interactive teaching and scientific research tool and improve work quality and efficiency

THE ROLE OF COSMIC-RAY PRESSURE IN ACCELERATING GALACTIC OUTFLOWS

Energy Technology Data Exchange (ETDEWEB)

Simpson, Christine M.; Pakmor, Rüdiger; Pfrommer, Christoph; Springel, Volker [Heidelberger Institut für Theoretische Studien, Schloss-Wolfsbrunnenweg 35, D-69118 Heidelberg (Germany); Marinacci, Federico [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Glover, Simon C. O. [Zentrum für Astronomie der Universität Heidelberg, ITA, Albert-Ueberle-Str. 2, D-69120 Heidelberg (Germany); Clark, Paul C. [School of Physics and Astronomy, Queen’s Buildings, The Parade, Cardiff University, Cardiff CF24 3AA (United Kingdom); Smith, Rowan J., E-mail: Christine.Simpson@h-its.org [Jodrell Bank Centre for Astrophysics, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom)

2016-08-20

We study the formation of galactic outflows from supernova (SN) explosions with the moving-mesh code AREPO in a stratified column of gas with a surface density similar to the Milky Way disk at the solar circle. We compare different simulation models for SN placement and energy feedback, including cosmic rays (CRs), and find that models that place SNe in dense gas and account for CR diffusion are able to drive outflows with similar mass loading as obtained from a random placement of SNe with no CRs. Despite this similarity, CR-driven outflows differ in several other key properties including their overall clumpiness and velocity. Moreover, the forces driving these outflows originate in different sources of pressure, with the CR diffusion model relying on non-thermal pressure gradients to create an outflow driven by internal pressure and the random-placement model depending on kinetic pressure gradients to propel a ballistic outflow. CRs therefore appear to be non-negligible physics in the formation of outflows from the interstellar medium.

Formation and spatial distribution of hypervelocity stars in AGN outflows

Science.gov (United States)

Wang, Xiawei; Loeb, Abraham

2018-05-01

We study star formation within outflows driven by active galactic nuclei (AGN) as a new source of hypervelocity stars (HVSs). Recent observations revealed active star formation inside a galactic outflow at a rate of ∼ 15M⊙yr-1 . We verify that the shells swept up by an AGN outflow are capable of cooling and fragmentation into cold clumps embedded in a hot tenuous gas via thermal instabilities. We show that cold clumps of ∼ 103 M⊙ are formed within ∼ 105 yrs. As a result, stars are produced along outflow's path, endowed with the outflow speed at their formation site. These HVSs travel through the galactic halo and eventually escape into the intergalactic medium. The expected instantaneous rate of star formation inside the outflow is ∼ 4 - 5 orders of magnitude greater than the average rate associated with previously proposed mechanisms for producing HVSs, such as the Hills mechanism and three-body interaction between a star and a black hole binary. We predict the spatial distribution of HVSs formed in AGN outflows for future observational probe.

How can the impact of PACS on inpatient length of hospital stay be established?

Science.gov (United States)

Bryan, Stirling; Muris, Nicole; Keen, Justin; Weatherburn, Gwyneth C.; Buxton, Martin J.

1994-05-01

Many have argued that the introduction of a large-scale PACS system into a hospital will bring about reductions in the length of inpatient hospital stays. There is currently no convicting empirical evidence to support such claims. As part of the independent evaluation exercise being undertaken alongside the Hammersmith Hospital PACS implementation, an assessment is being made of the impact of PACS on length of stay for selected patient groups. This paper reports the general research methods being employed to undertake this assessment and provides some baseline results from the analysis of total hip replacement patients and total knee replacement patients treated prior to the introduction of PACS.

Characterization of molecular outflows in the substellar domain

Energy Technology Data Exchange (ETDEWEB)

Phan-Bao, Ngoc; Dang-Duc, Cuong [Department of Physics, International University-Vietnam National University HCM, Block 6, Linh Trung Ward, Thu Duc District, Ho Chi Minh City (Viet Nam); Lee, Chin-Fei; Ho, Paul T. P. [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 106, Taiwan (China); Li, Di, E-mail: pbngoc@hcmiu.edu.vn, E-mail: pbngoc@asiaa.sinica.edu.tw [National Astronomical Observatories, Chinese Academy of Science, Chaoyang District Datun Rd A20, Beijing (China)

2014-11-01

We report here our latest search for molecular outflows from young brown dwarfs and very low-mass stars in nearby star-forming regions. We have observed three sources in Taurus with the Submillimeter Array and the Combined Array for Research in Millimeter-wave Astronomy at 230 GHz frequency to search for CO J = 2 → 1 outflows. We obtain a tentative detection of a redshifted and extended gas lobe at about 10 arcsec from the source GM Tau, a young brown dwarf in Taurus with an estimated mass of 73 M {sub J}, which is right below the hydrogen-burning limit. No blueshifted emission around the brown dwarf position is detected. The redshifted gas lobe that is elongated in the northeast direction suggests a possible bipolar outflow from the source with a position angle of about 36°. Assuming that the redshifted emission is outflow emission from GM Tau, we then estimate a molecular outflow mass in the range from 1.9 × 10{sup –6} M {sub ☉} to 2.9 × 10{sup –5} M {sub ☉} and an outflow mass-loss rate from 2.7 × 10{sup –9} M {sub ☉} yr{sup –1} to 4.1 × 10{sup –8} M {sub ☉} yr{sup –1}. These values are comparable to those we have observed in the young brown dwarf ISO-Oph 102 of 60 M {sub J} in ρ Ophiuchi and the very low-mass star MHO 5 of 90 M {sub J} in Taurus. Our results suggest that the outflow process in very low-mass objects is episodic with a duration of a few thousand years and the outflow rate of active episodes does not significantly change for different stages of the formation process of very low-mass objects. This may provide us with important implications that clarify the formation process of brown dwarfs.

SPITZER AND HERSCHEL MULTIWAVELENGTH CHARACTERIZATION OF THE DUST CONTENT OF EVOLVED H II REGIONS

Energy Technology Data Exchange (ETDEWEB)

Paladini, R. [NASA Herschel Science Center, California Institute of Technology, 1200, East California Boulevard, Pasadena, CA 91125 (United States); Umana, G. [INAF-Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania (Italy); Veneziani, M.; Noriega-Crespo, A. [Infrared Processing and Analysis Center, California Institute of Technology, 1200, East California Boulevard, Pasadena, CA 91125 (United States); Anderson, L. D. [Department of Physics, West Virginia University, Morgantown, WV 26506 (United States); Piacentini, F. [Dipartimento di Fisica, Universita di Roma La Sapienza, I-00185 Roma (Italy); Pinheiro Goncalves, D. [Department of Astronomy and Astrophysics, University of Toronto 50 George Street, Toronto, ON M5S 3H4 (Canada); Paradis, D.; Bernard, J.-P. [Centre d' Etude Spatiale des Rayonnements, 9 Avenue du Colonel Roche, F-31028 Toulouse Cedex 4 (France); Tibbs, C. T. [Spitzer Science Center, California Institute of Technology, 1200, East California Boulevard, Pasadena, CA 91125 (United States); Natoli, P., E-mail: paladini@ipac.caltech.edu [Istituto Nazionale di Fisica Nucleare, Sezione Ferrara, I-44100 Ferrara (Italy)

2012-12-01

We have analyzed a uniform sample of 16 evolved H II regions located in a 2 Degree-Sign Multiplication-Sign 2 Degree-Sign Galactic field centered at (l,b) = (30 Degree-Sign , 0 Degree-Sign ) and observed as part of the Herschel Hi-GAL survey. The evolutionary stage of these H II regions was established using ancillary radio-continuum data. By combining Hi-GAL PACS (70 {mu}m, 160 {mu}m) and SPIRE (250 {mu}m, 350 {mu}m, and 500 {mu}m) measurements with MIPSGAL 24 {mu}m data, we built spectral energy distributions of the sources and showed that a two-component gray-body model is a good representation of the data. In particular, wavelengths >70 {mu}m appear to trace a cold dust component, for which we estimated an equilibrium temperature of the big grains (BGs) in the range 20-30 K, while for {lambda} < 70 {mu}m, the data indicate the presence of a warm dust component at temperatures of the order of 50-90 K. This analysis also revealed that dust is present in the interior of H II regions, although likely not in a large amount. In addition, the data seem to corroborate the hypothesis that the main mechanism responsible for the (partial) depletion of dust in H II regions is radiation-pressure-driven drift. In this framework, we speculated that the 24 {mu}m emission that spatially correlates with ionized gas might be associated with either very small grain or BG replenishment, as recently proposed for the case of wind-blown bubbles. Finally, we found that evolved H II regions are characterized by distinctive far-IR and submillimeter colors, which can be used as diagnostics for their identification in unresolved Galactic and extragalactic regions.

Lessons learned from a whole hospital PACS installation. Picture Archiving and Communication System.

Science.gov (United States)

Pilling, J R

2002-09-01

The Norfolk and Norwich University Hospital has incorporated a fully filmless Picture Archiving and Communication System (PACS) as part of a new hospital provision using PFI funding. The PACS project has been very successful and has met with unanimous acclaim from radiologists and clinicians. A project of this size cannot be achieved without learning some lessons from mistakes and recognising areas where attention to detail resulted in a successful implementation. This paper considers the successes and problems encountered in a large PACS installation.

A study on reduction effect of processing wastewater by introduction of PACS

International Nuclear Information System (INIS)

Ko, Shin Kwan; Yang, Han Jun; Han, Dong Kyoon; Kim, Wook Dong; Kang, Bung Sam

2007-01-01

There are some positive effects by the introduction of PACS (Picture Archiving Communication System). This study is to analyze the mutual relation between before and after of the introduction of PACS in terms of the environment effect. It is supposed to cause the reduction of developing and fixing wastewater according to the increase in the rate of a non-film. This study also show the amount of wastewater. Target places were the department of image medicine (diagnostic radiation) of the general hospitals in Seoul and Gyeonggido, which are equipped with full PACS. The authors examined questionnaires on the number of projection, the number of indirect projection, the amount of the film used, the number of radiation image CD loan, the amount of the developing and fixing solution used, the change of the amount of fixing wastewater. According to the analysis, we analyzed the change of the amount of developing and fixing solution per a film and the change of the amount of developing and fixing wastewater which is supposed to be reduced proportionally by the introduction of PACS. We got conclusion as below after analyzing 8 hospitals except the largest and the least amount of examination, film used, developing and fixing solution and the amount of developing and fixing wastewater in order to decrease the deviation from 10 general hospitals located in Seoul and Gyeonggido. We compared data one year before adopting PACS Versus 3 years after adopting PACS. The frequencies of examination increased to 7,357.7 cases per month but the amount of film used decreased to 90%, from 42,774.4 to 4,181.88 after adopting the PACS. 3 years after adopting PACS, monthly average amount of developing solution used decreased to 92% and the monthly average amount of fixing solution decreased to 86%. Monthly average amount of developing solution used per film increased to 1.49 times and fixing solution increased as much as three times. Monthly average wastewater for developing decreased to 88

PACS and its hospital-wide implementation: A case study at the Madigan Army Medical Center

International Nuclear Information System (INIS)

Choi, Hyung Sik; Kim, Yong Min; Smith, Donald V.; Bender, Gregory N.

1993-01-01

PACS represents the future of radiology in modern hospitals. Workstations and databases can be developed to substantially increase clinician's productivity, improve diagnostic accuracy, and make a large amount of knowledge and patient information available on-line to the physician. Currently, there are several hospitals in the process of implementing a total PACS system. They include Madigan Army Medical Center (Tacoma, Washington), VA Hospital in Baltimore, and Hammersmith Hospital in London (1). In order to provide the radiologist, the clinicians, and other health personnel in Korea with the general concept of PACS and its up-to-date status report, we describe the MDIS system being implemented in MAMC (Madigan Army Medical Center) which is the first hospital-wide large-scale PACS in the world. The major PACS components in MAMC have been installed since March 1992 and the full system implementation will be completed by summer 1993. The goal of the MDIS system in MAMC is to increase to more than 90% filmless by the end of 1993. In this paper, we discuss the introduction and background of PACS and its potential benefits, the current status of PACS installation in MAMC and the future plan, and the flow of image data and text information in MAMC

Cost-effective data storage/archival subsystem for functional PACS

Science.gov (United States)

Chen, Y. P.; Kim, Yongmin

1993-09-01

Not the least of the requirements of a workable PACS is the ability to store and archive vast amounts of information. A medium-size hospital will generate between 1 and 2 TBytes of data annually on a fully functional PACS. A high-speed image transmission network coupled with a comparably high-speed central data storage unit can make local memory and magnetic disks in the PACS workstations less critical and, in an extreme case, unnecessary. Under these circumstances, the capacity and performance of the central data storage subsystem and database is critical in determining the response time at the workstations, thus significantly affecting clinical acceptability. The central data storage subsystem not only needs to provide sufficient capacity to store about ten days worth of images (five days worth of new studies, and on the average, about one comparison study for each new study), but also supplies images to the requesting workstation in a timely fashion. The database must provide fast retrieval responses upon users' requests for images. This paper analyzes both advantages and disadvantages of multiple parallel transfer disks versus RAID disks for short-term central data storage subsystem, as well as optical disk jukebox versus digital recorder tape subsystem for long-term archive. Furthermore, an example high-performance cost-effective storage subsystem which integrates both the RAID disks and high-speed digital tape subsystem as a cost-effective PACS data storage/archival unit are presented.

Decoupling of magnetic fields in collapsing protostellar envelopes and disc formation and fragmentation

Science.gov (United States)

Zhao, Bo; Caselli, Paola; Li, Zhi-Yun; Krasnopolsky, Ruben

2018-02-01

Efficient magnetic braking is a formidable obstacle to the formation of rotationally supported discs (RSDs) around protostars in magnetized dense cores. We have previously shown, through 2D (axisymmetric) non-ideal magnetohydrodynamic simulations, that removing very small grains (VSGs: ∼10 Å to few 100 Å) can greatly enhance ambipolar diffusion and enable the formation of RSDs. Here, we extend the simulations of disc formation enabled by VSG removal to 3D. We find that the key to this scenario of disc formation is that the drift velocity of the magnetic field almost cancels out the infall velocity of the neutrals in the 102-103 au scale 'pseudo-disc' where the field lines are most severely pinched and most of protostellar envelope mass infall occurs. As a result, the bulk neutral envelope matter can collapse without dragging much magnetic flux into the disc-forming region, which lowers the magnetic braking efficiency. We find that the initial discs enabled by VSG removal tend to be Toomre-unstable, which leads to the formation of prominent spiral structures that function as centrifugal barriers. The piling-up of infall material near the centrifugal barrier often produces dense fragments of tens of Jupiter masses, especially in cores that are not too strongly magnetized. Some fragments accrete on to the central stellar object, producing bursts in mass accretion rate. Others are longer lived, although whether they can survive for a long term to produce multiple systems remains to be ascertained. Our results highlight the importance of dust grain evolution in determining the formation and properties of protostellar discs and potentially multiple systems.

WARM EXTENDED DENSE GAS AT THE HEART OF A COLD COLLAPSING DENSE CORE

International Nuclear Information System (INIS)

Shinnaga, Hiroko; Phillips, Thomas G.; Furuya, Ray S.; Kitamura, Yoshimi

2009-01-01

In order to investigate when and how the birth of a protostellar core occurs, we made survey observations of four well-studied dense cores in the Taurus molecular cloud using CO transitions in submillimeter bands. We report here the detection of unexpectedly warm (∼30-70 K), extended (radius of ∼2400 AU), dense (a few times 10 5 cm -3 ) gas at the heart of one of the dense cores, L1521F (MC27), within the cold dynamically collapsing components. We argue that the detected warm, extended, dense gas may originate from shock regions caused by collisions between the dynamically collapsing components and outflowing/rotating components within the dense core. We propose a new stage of star formation, 'warm-in-cold core stage (WICCS)', i.e., the cold collapsing envelope encases the warm extended dense gas at the center due to the formation of a protostellar core. WICCS would constitute a missing link in evolution between a cold quiescent starless core and a young protostar in class 0 stage that has a large-scale bipolar outflow.

Enterprise-wide PACS: beyond radiology, an architecture to manage all medical images.

Science.gov (United States)

Bandon, David; Lovis, Christian; Geissbühler, Antoine; Vallée, Jean-Paul

2005-08-01

Picture archiving and communication systems (PACS) have the vocation to manage all medical images acquired within the hospital. To address the various situations encountered in the imaging specialties, the traditional architecture used for the radiology department has to evolve. We present our preliminarily results toward an enterprise-wide PACS intended to support all kind of image production in medicine, from biomolecular images to whole-body pictures. Our solution is based on an existing radiologic PACS system from which images are distributed through an electronic patient record to all care facilities. This platform is enriched with a flexible integration framework supporting digital image communication in medicine (DICOM) and DICOM-XML formats. In addition, a generic workflow engine highly customizable is used to drive work processes. Echocardiology; hematology; ear, nose, and throat; and dermatology, including wounds, follow-up is the first implemented extensions outside of radiology. We also propose a global strategy for further developments based on three possible architectures for an enterprise-wide PACS.

Wind influence on a coastal buoyant outflow

Science.gov (United States)

Whitney, Michael M.; Garvine, Richard W.

2005-03-01

This paper investigates the interplay between river discharge and winds in forcing coastal buoyant outflows. During light winds a plume influenced by the Earth's rotation will flow down shelf (in the direction of Kelvin wave propagation) as a slender buoyancy-driven coastal current. Downwelling favorable winds augment this down-shelf flow, narrow the plume, and mix the water column. Upwelling favorable winds drive currents that counter the buoyancy-driven flow, spread plume waters offshore, and rapidly mix buoyant waters. Two criteria are developed to assess the wind influence on a buoyant outflow. The wind strength index (Ws) determines whether a plume's along-shelf flow is in a wind-driven or buoyancy-driven state. Ws is the ratio of the wind-driven and buoyancy-driven along-shelf velocities. Wind influence on across-shelf plume structure is rated with a timescale (ttilt) for the isopycnal tilting caused by wind-driven Ekman circulation. These criteria are used to characterize wind influence on the Delaware Coastal Current and can be applied to other coastal buoyant outflows. The Delaware buoyant outflow is simulated for springtime high-river discharge conditions. Simulation results and Ws values reveal that the coastal current is buoyancy-driven most of the time (∣Ws∣ Wind events, however, overwhelm the buoyancy-driven flow (∣Ws∣ > 1) several times during the high-discharge period. Strong upwelling events reverse the buoyant outflow; they constitute an important mechanism for transporting fresh water up shelf. Across-shelf plume structure is more sensitive to wind influence than the along-shelf flow. Values of ttilt indicate that moderate or strong winds persisting throughout a day can modify plume width significantly. Plume widening during upwelling events is accompanied by mixing that can erase the buoyant outflow.

Quasar outflow energetics from broad absorption line variability

Science.gov (United States)

McGraw, S. M.; Shields, J. C.; Hamann, F. W.; Capellupo, D. M.; Herbst, H.

2018-03-01

Quasar outflows have long been recognized as potential contributors to the co-evolution between supermassive black holes (SMBHs) and their host galaxies. The role of outflows in active galactic nucleus (AGN) feedback processes can be better understood by placing observational constraints on wind locations and kinetic energies. We utilize broad absorption line (BAL) variability to investigate the properties of a sample of 71 BAL quasars with P V broad absorption. The presence of P V BALs indicates that other BALs like C IV are saturated, such that variability in those lines favours clouds crossing the line of sight. We use these constraints with measurements of BAL variability to estimate outflow locations and energetics. Our data set consists of multiple-epoch spectra from the Sloan Digital Sky Survey and MDM Observatory. We detect significant (4σ) BAL variations from 10 quasars in our sample over rest-frame time-scales between ≤0.2-3.8 yr. Our derived distances for the 10 variable outflows are nominally ≲ 1-10 pc from the SMBH using the transverse-motion scenario, and ≲ 100-1000 pc from the central source using ionization-change considerations. These distances, in combination with the estimated high outflow column densities (i.e. NH ≳ 1022 cm-2), yield outflow kinetic luminosities between ˜ 0.001 and 1 times the bolometric luminosity of the quasar, indicating that many absorber energies within our sample are viable for AGN feedback.

OPTICAL AND NEAR-INFRARED SHOCKS IN THE L988 CLOUD COMPLEX

International Nuclear Information System (INIS)

Walawender, J.; Reipurth, B.; Bally, J.

2013-01-01

We have searched the Lynds 988 dark cloud complex for optical (Hα and [S II]) and near-IR (H 2 2.12 μm) shocks from protostellar outflows. We find 20 new Herbig-Haro objects and 6 new H 2 shocks (MHO objects), 3 of which are cross detections. Using the morphology in the optical and near-IR, we connect several of these shocks into at least five distinct outflow systems and identify their source protostars from catalogs of infrared sources. Two outflows in the cloud, from IRAS 21014+5001 and IRAS 21007+4951, are in excess of 1 pc in length. The IRAS 21007+4951 outflow has carved a large cavity in the cloud through which background stars can be seen. Also, we have found an optical shock which is the counterflow to the previously discovered ''northwest outflow'' from LkHα 324SE

Discoverers of the universe William and Caroline Herschel

CERN Document Server

Hoskin, Michael

2011-01-01

Discoverers of the Universe tells the gripping story of William Herschel, the brilliant, fiercely ambitious, emotionally complex musician and composer who became court astronomer to Britain's King George III, and of William's sister, Caroline, who assisted him in his observations of the night sky and became an accomplished astronomer in her own right. Together, they transformed our view of the universe from the unchanging, mechanical creation of Newton's clockmaker god to the ever-evolving, incredibly dynamic cosmos that it truly is. William was in his forties when his amateur observations usi

William Herschel during the 1780-1810 era: A natural historian studies "maturation" of stars over immeasurable time

Science.gov (United States)

Sullivan, Woody

2015-01-01

(A) William Herschel (1738-1822) considered himself a natural historian, different only from the usual natural historians in that his focus was on stars and nebulae rather than plants, animals, and minerals. In this regard, he developed ideas concerning changes over very long times, inferred from his catalogues of 2500 star clusters and nebulae. By assuming that all the observed types of star clusters and morphologies of nebulae represented different stages in the formation of stars and clusters under the action of gravity, Herschel argued for a sequence of "maturation," or evolution as we would call it. He could put no definite time scale on these dynamic processes, but inspired by contemporary geologists such as James Hutton and John Michell (yes, he was a geologist, too!), he felt that the time scales must be very long. In further support, he photometrically estimated that the very faintest stars that he could see in his giant 40-ft telescope were about two million light-years distant. Herschel's findings on the structure and age of the Milky Way system, his "construction of the heavens," were also influenced by geological notions of the formation and subsequent warping of strata over long times, and the geologists' attempts to uncover the interior and distant past of the Earth. (B) Herschel was a very successful professional musician for two decades, primarily in the fashionable resort city of Bath, England. And then he discovered Uranus in 1781 at age 43, an event that catapulted him into celebrity and allowed him immediately to transform himself into a full-time astronomer. He composed over twenty symphonies, many concertos, and a large number of organ and choral works. During this session, a chorus of University of Washington students will present a short concert featuring Herschel's most popular composition, a novelty number called "The Eccho Catch," as well as contemporary pieces with astronomical themes by other composers.

From shared data to sharing workflow: Merging PACS and teleradiology

International Nuclear Information System (INIS)

Benjamin, Menashe; Aradi, Yinon; Shreiber, Reuven

2010-01-01

Due to a host of technological, interface, operational and workflow limitations, teleradiology and PACS/RIS were historically developed as separate systems serving different purposes. PACS/RIS handled local radiology storage and workflow management while teleradiology addressed remote access to images. Today advanced PACS/RIS support complete site radiology workflow for attending physicians, whether on-site or remote. In parallel, teleradiology has emerged into a service of providing remote, off-hours, coverage for emergency radiology and to a lesser extent subspecialty reading to subscribing sites and radiology groups. When attending radiologists use teleradiology for remote access to a site, they may share all relevant patient data and participate in the site's workflow like their on-site peers. The operation gets cumbersome and time consuming when these radiologists serve multi-sites, each requiring a different remote access, or when the sites do not employ the same PACS/RIS/Reporting Systems and do not share the same ownership. The least efficient operation is of teleradiology companies engaged in reading for multiple facilities. As these services typically employ non-local radiologists, they are allowed to share some of the available patient data necessary to provide an emergency report but, by enlarge, they do not share the workflow of the sites they serve. Radiology stakeholders usually prefer to have their own radiologists perform all radiology tasks including interpretation of off-hour examinations. It is possible with current technology to create a system that combines the benefits of local radiology services to multiple sites with the advantages offered by adding subspecialty and off-hours emergency services through teleradiology. Such a system increases efficiency for the radiology groups by enabling all users, regardless of location, to work 'local' and fully participate in the workflow of every site. We refer to such a system as SuperPACS.

Outflow and hot dust emission in broad absorption line quasars

Energy Technology Data Exchange (ETDEWEB)

Zhang, Shaohua; Zhou, Hongyan [Polar Research Institute of China, 451 Jinqiao Road, Shanghai 200136 (China); Wang, Huiyuan; Wang, Tinggui; Xing, Feijun; Jiang, Peng [Key Laboratory for Research in Galaxies and Cosmology, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, Anhui 230026 (China); Zhang, Kai, E-mail: zhangshaohua@pric.gov.cn, E-mail: whywang@mail.ustc.edu.cn [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China)

2014-05-01

We have investigated a sample of 2099 broad absorption line (BAL) quasars with z = 1.7-2.2 built from the Sloan Digital Sky Survey Data Release Seven and the Wide-field Infrared Survey. This sample is collected from two BAL quasar samples in the literature and is refined by our new algorithm. Correlations of outflow velocity and strength with a hot dust indicator (β{sub NIR}) and other quasar physical parameters—such as an Eddington ratio, luminosity, and a UV continuum slope—are explored in order to figure out which parameters drive outflows. Here β{sub NIR} is the near-infrared continuum slope, which is a good indicator of the amount of hot dust emission relative to the accretion disk emission. We confirm previous findings that outflow properties moderately or weakly depend on the Eddington ratio, UV slope, and luminosity. For the first time, we report moderate and significant correlations of outflow strength and velocity with β{sub NIR} in BAL quasars. It is consistent with the behavior of blueshifted broad emission lines in non-BAL quasars. The statistical analysis and composite spectra study both reveal that outflow strength and velocity are more strongly correlated with β{sub NIR} than the Eddington ratio, luminosity, and UV slope. In particular, the composites show that the entire C IV absorption profile shifts blueward and broadens as β{sub NIR} increases, while the Eddington ratio and UV slope only affect the high and low velocity part of outflows, respectively. We discuss several potential processes and suggest that the dusty outflow scenario, i.e., that dust is intrinsic to outflows and may contribute to the outflow acceleration, is most likely.

PACS: Do clinical users benefit from it as a training adjunct? | van ...

African Journals Online (AJOL)

Although a PACS relates specifically to the archiving and retrieval of radiological images and reports, it became clear from the feedback received from medical clinicians (who ... The advantages of PACS as a positive training adjunct were highlighted in the areas of multi-site viewing and consultation, the possibility of image ...

Active galactic nucleus outflows in galaxy discs

Science.gov (United States)

Hartwig, Tilman; Volonteri, Marta; Dashyan, Gohar

2018-05-01

Galactic outflows, driven by active galactic nuclei (AGNs), play a crucial role in galaxy formation and in the self-regulated growth of supermassive black holes (BHs). AGN feedback couples to and affects gas, rather than stars, and in many, if not most, gas-rich galaxies cold gas is rotationally supported and settles in a disc. We present a 2D analytical model for AGN-driven outflows in a gaseous disc and demonstrate the main improvements, compared to existing 1D solutions. We find significant differences for the outflow dynamics and wind efficiency. The outflow is energy-driven due to inefficient cooling up to a certain AGN luminosity (˜1043 erg s-1 in our fiducial model), above which the outflow remains momentum-driven in the disc up to galactic scales. We reproduce results of 3D simulations that gas is preferentially ejected perpendicular to the disc and find that the fraction of ejected interstellar medium is lower than in 1D models. The recovery time of gas in the disc, defined as the free-fall time from the radius to which the AGN pushes the ISM at most, is remarkably short, of the order 1 Myr. This indicates that AGN-driven winds cannot suppress BH growth for long. Without the inclusion of supernova feedback, we find a scaling of the BH mass with the halo velocity dispersion of MBH ∝ σ4.8.

Operator interface design considerations for a PACS information management system

Science.gov (United States)

Steinke, James E.; Nabijee, Kamal H.; Freeman, Rick H.; Prior, Fred W.

1990-08-01

As prototype PACS grow into fully digital departmental and hospital-wide systems, effective information storage and retrieval mechanisms become increasingly important. Thus far, designers of PACS workstations have concentrated on image communication and display functionality. The new challenge is to provide appropriate operator interface environments to facilitate information retrieval. The "Marburg Model" 1 provides a detailed analysis of the functions, control flows and data structures used in Radiology. It identifies a set of "actors" who perform information manipulation functions. Drawing on this model and its associated methodology it is possible to identify four modes of use of information systems in Radiology: Clinical Routine, Research, Consultation, and Administration. Each mode has its own specific access requirements and views of information. An operator interface strategy appropriate for each mode will be proposed. Clinical Routine mode is the principal concern of PACS primary diagnosis workstations. In a full PACS implementation, such workstations must provide a simple and consistent navigational aid for the on-line image database, a local work list of cases to be reviewed, and easy access to information from other hospital information systems. A hierarchical method of information access is preferred because it provides the ability to start at high-level entities and iteratively narrow the scope of information from which to select subsequent operations. An implementation using hierarchical, nested software windows which fulfills such requirements shall be examined.

Whole-slide imaging in pathology: the potential impact on PACS

Science.gov (United States)

Horii, Steven C.

2007-03-01

Pathology, the medical specialty charged with the evaluation of macroscopic and microscopic aspects of disease, is increasingly turning to digital imaging. While the conventional tissue blocks and glass slides form an "archive" that pathology departments must maintain, digital images acquired from microscopes or digital slide scanners are increasingly used for telepathology, consultation, and intra-facility communication. Since many healthcare facilities are moving to "enterprise PACS" with departments in addition to radiology using the infrastructure of such systems, some understanding of the potential of whole-slide digital images is important. Network and storage designers, in particular, are very likely to be impacted if a significant number of such images are to be moved on, or stored (even temporarily) in, enterprise PACS. As an example, a typical commercial whole-slide imaging system typically generates 15 gigabytes per slide scanned (per focal plane). Many of these whole-slide scanners have a throughput of 1000 slides per day. If that full capacity is used and all the resulting digital data is moved to the enterprise PACS, it amounts to 15 terabytes per day; the amount of data a large radiology department might generate in a year or two. This paper will review both the clinical scenarios of whole-slide imaging as well as the resulting data volumes. The author will emphasize the potential PACS infrastructure impact of such huge data volumes.

Combined PACS and intranet information system in a University Hospital; Kombiniertes PACS und Intranet-Informationssystem an einem Universitaetsklinikum

Energy Technology Data Exchange (ETDEWEB)

Heiss, D.; Pfluger, T.; Pfeifer, K.J.; Hahn, K. [Muenchen Univ. (Germany). Inst. fuer Radiologische Diagnostik; Koenig, A.; Endres, S. [Muenchen Univ. (Germany). Medizinische Klinik Innenstadt

2000-06-01

Purpose: The Department of Radiology at the University Hospital Innenstadt Munich provides all clinical departments of a large university hospital with several radiology units at different locations. During the last four years all units have been fully digitalized with a stepwise installation of a PACS. The PACS also processes images from the Nuclear Medicine Department. Methods: As image modalities, archive systems and review workstations, we use devices from multiple vendors, which are integrated into a consistent system using the DICOM standard. The hospital has developed its own RIS and an intranet information system, which provides access to all reports and images from radiology for all clinical departments inside the hospital. Additionally, other clinical information such as laboratory results or ECG examinations are available through the system. Results: After one year of operation, the system succeeded in the clinical routine work as the primary source for radiological reports and images as well as for laboratory values. Conclusion: The advantages of digitalization were, besides reduction of film cost, especially optimizations of work flow with access to digital images from every where at any time. (orig.) [German] Ziel: Das Institut fuer Radiologische Diagnostik am Universitaetsklinikum Muenchen - Innenstadt versorgt mit mehreren, dezentral gelegenen Roentgenbereichen alle klinischen Abteilungen eines grossen Universitaetsklinikums. In einem Projekt der vergangenen vier Jahre wurden alle Bereiche durch die schrittweise Installation eines PACS vollstaendig digitalisiert. Dabei wurden auch nuklearmedizinische Bilddaten aus der Klinik und Poliklinik fuer Nuklearmedizin im System verarbeitet. Methoden: Eingesetzt wurden als Bilderzeuger, Archivsystem und Befundungsstationen Geraete unterschiedlicher Hersteller, die dank des DICOM Standards in einem einheitlichen System integriert sind. Neben dem PACS wurde von Mitarbeitern der Klinik ein RIS und ein Intranet

PHOTOMETRIC REDSHIFTS OF SUBMILLIMETER GALAXIES

International Nuclear Information System (INIS)

Chakrabarti, Sukanya; Magnelli, Benjamin; Lutz, Dieter; Berta, Stefano; Popesso, Paola; McKee, Christopher F.; Pozzi, Francesca

2013-01-01

We use the photometric redshift method of Chakrabarti and McKee to infer photometric redshifts of submillimeter galaxies with far-IR (FIR) Herschel data obtained as part of the PACS Evolutionary Probe program. For the sample with spectroscopic redshifts, we demonstrate the validity of this method over a large range of redshifts (4 ∼> z ∼> 0.3) and luminosities, finding an average accuracy in (1 + z phot )/(1 + z spec ) of 10%. Thus, this method is more accurate than other FIR photometric redshift methods. This method is different from typical FIR photometric methods in deriving redshifts from the light-to-gas mass (L/M) ratio of infrared-bright galaxies inferred from the FIR spectral energy distribution, rather than dust temperatures. To assess the dependence of our photometric redshift method on the data in this sample, we contrast the average accuracy of our method when we use PACS data, versus SPIRE data, versus both PACS and SPIRE data. We also discuss potential selection effects that may affect the Herschel sample. Once the redshift is derived, we can determine physical properties of infrared-bright galaxies, including the temperature variation within the dust envelope, luminosity, mass, and surface density. We use data from the GOODS-S field to calculate the star formation rate density (SFRD) of submillimeter bright sources detected by AzTEC and PACS. The AzTEC-PACS sources, which have a threshold 850 μm flux ∼> 5 mJy, contribute 15% of the SFRD from all ultraluminous infrared galaxies (L IR ∼> 10 12 L ☉ ), and 3% of the total SFRD at z ∼ 2

The impact of a picture archiving and communication system (PACS) upon an intensive care unit

International Nuclear Information System (INIS)

Watkins, Jessamy; Weatherburn, Gwyn; Bryan, Stirling

2000-01-01

Objective: The aim of the study was to assess the effect of the introduction of PACS (Picture Archiving and Communication System) upon image availability in an Intensive Care Unit (ICU) and the consequent impact upon the behaviour of the ICU physicians, in terms of the initiation of image-based clinical actions. Design: A before and after study was used to compare the speed of image availability prior to, and following, the implementation of a hospital-wide PACS. Setting: The research was part of an economic evaluation of PACS at Hammersmith Hospital, West London. Patients and participants: All ICU patients who were X-rayed during two pre-PACS and one post-PACS data collection periods were included within the study. Measurements: The times of: the X-ray request; acquisition; availability on ICU; and of any image-based clinical action taken by the ICU physician were recorded by radiographers and ICU physicians. Results: PACS significantly reduced the time between request and image availability on ICU for routine X-rays but did not have any measurable impact upon the time clinical actions were initiated by ICU physicians. The data on non-routine images were statistically inconclusive. Conclusions: This study shows that PACS significantly improves the speed of delivery of routine images to the ICU, but it appears that the instigation of image-based clinical actions is determined by other organisational factors in ICU, such as ward rounds, rather than the availability of the image for viewing. Further work is required on non-routine X-rays to clarify the impact of PACS on physician behaviour in clinically urgent situations

A strongly quasiconvex PAC-Bayesian bound

DEFF Research Database (Denmark)

Thiemann, Niklas; Igel, Christian; Wintenberger, Olivier

2017-01-01

We propose a new PAC-Bayesian bound and a way of constructing a hypothesis space, so that the bound is convex in the posterior distribution and also convex in a trade-off parameter between empirical performance of the posterior distribution and its complexity. The complexity is measured by the Ku...

Design criteria for a data base management system for a PACS at Georgetown University Hospital

International Nuclear Information System (INIS)

Fahey, F.H.; Wang, P.C.; Mun, S.K.; Choyke, P.L.; Benson, H.R.; Duerinckx, A.; Elliott, L.P.

1986-01-01

A major goal of a radiologic picture archival and communication system (PACS) is to increase the availability of the data to the users who require access to them. This is done by providing the data in a digital form which can be readily communicated and archived. In this manner, the PACS can be seen as a specific example of a data base managements system (DBMS). The PACS/DBMS should organize the data base in such a way as to provide its users with the data they require in a timely and efficient manner. The ability to integrate the variety of data into common data base should lead to a more complete and relevant representation of the available information. A PACS/DBMS is not only unique in the types of data contained in the data base and its different users but also in the volume of data that are entered into the system and transferred within the system each day. Consideration of these characteristics leads to the definition of functional criteria for the PACS/DBMS. This report discusses the criteria that will be used in the design of a DBMS for a PACS at Georgetown University Hospital. (Auth.)

OUTFLOW AND HOT DUST EMISSION IN HIGH-REDSHIFT QUASARS

International Nuclear Information System (INIS)

Wang, Huiyuan; Xing, Feijun; Wang, Tinggui; Zhou, Hongyan; Zhang, Kai; Zhang, Shaohua

2013-01-01

Correlations of hot dust emission with outflow properties are investigated, based on a large z ∼ 2 non-broad absorption line quasar sample built from the Wide-field Infrared Survey and the Sloan Digital Sky Survey data releases. We use the near-infrared slope and the infrared to UV luminosity ratio to indicate the hot dust emission relative to the emission from the accretion disk. In our luminous quasars, these hot dust emission indicators are almost independent of the fundamental parameters, such as luminosity, Eddington ratio and black hole mass, but moderately dependent on the blueshift and asymmetry index (BAI) and FWHM of C IV lines. Interestingly, the latter two correlations dramatically strengthen with increasing Eddington ratio. We suggest that, in high Eddington ratio quasars, C IV regions are dominated by outflows so the BAI and FWHM (C IV) can reliably reflect the general properties and velocity of outflows, respectively. In low Eddington ratio quasars, on the other hand, C IV lines are primarily emitted by virialized gas so the BAI and FWHM (C IV) become less sensitive to outflows. Therefore, the correlations for the highest Eddington ratio quasars are more likely to represent the true dependence of hot dust emission on outflows and the correlations for the entire sample are significantly diluted by the low Eddington ratio quasars. Our results show that an outflow with a large BAI or velocity can double the hot dust emission on average. We suggest that outflows either contain hot dust in themselves or interact with the dusty interstellar medium or torus

The Simbol-X Perspective on the Physics of Quasar Outflows

Science.gov (United States)

Giustini, M.; Cappi, M.; Vignali, C.; Palumbo, G. G. C.; Fiore, F.; Malaguti, G.

2009-05-01

There is increasing evidence that quasar outflows may play a key role in providing the feedback between AGN/QSOs and their surrounding (and feeding) media, in regulating the central supermassive black hole growth and the galaxy formation and, on larger scales, in shaping the growth of cosmic structures (see e.g. [1]). X-ray observations of quasar outflows are crucial to probe their innermost parts and assess the global energetics entrained in the outflow by studying its most extreme (in terms of velocity, ionization state, mass outflow rate) phases. Simbol-X-with its high effective area in the Fe K energy band and above-will allow the detection and the characterization of powerful outflows in bright, nearby AGN and notably also in moderately faint AGN, thus shedding light on feedback processes in these objects.

Peligros del átomo pacífico

Directory of Open Access Journals (Sweden)

Juan Zarco de Gea

1962-07-01

Full Text Available Expuestas en el artículo anterior las ventajas que el hombre puede obtener del uso de la energía atómica para fines pacíficos: industria, agricultura, medicina, investigación científica, etc., parece oportuno examinar ahora el reverso de la medalla y estudiar los inconvenientes de ese mismo uso pacífico de las fuerzas atómicas; inconvenientes, dicho sea de paso, que también existen en el aprovechamiento de otras fuerzas naturales, físicas o químicas, en las minas, fábricas, laboratorios y otras muchas empresas de toda índole; pero tratándose de las energías nucleares entran en juego factores nuevos y especiales, que llevan el asunto a terrenos diferentes: moral, político, de salud pública, etc.

Correlations between the stellar and disc properties of Taurus PMS stars in the GASPS sample

NARCIS (Netherlands)

Alonso-Martínez, Miguel; Riviere-Marichalar, Pablo; Pascual, Natalia; Montesinos, Benjamín; Howard, Christian D.; Sandell, Göran; Meeus, Gwendolyn; Eiroa, Carlos; Dent, Bill

The Herschel Open Time Key Programme GASPS (P.I. B. Dent) has observed a large number of pre-main sequence TTauri stars in Taurus with PACS (photometry and spectroscopy). In addition, we have also carried out new ground-based optical and near-IR observations (photometry and spectroscopy) of most of

ALMA Studies of the Disk-Jet-Outflow Connection

Science.gov (United States)

Dougados, Catherine; Louvet, F.; Mardones, D.; Cabrit, S.

2017-06-01

I will describe in this contribution recent results obtained with ALMA on the origin of the disk/jet/outflow connexion in T Tauri stars. I will first present ALMA observations of the disk associated with the jet source Th 28, which question previous jet rotation measurements in this source and the implications drawn from them. I will then discuss Cycle 2 ALMA observations of the disk and small scale CO outflow associated with the prototypical edge-on HH 30 source. The unprecedented angular resolution of this dataset brings new constraints on the origin of the CO outflows in young stars.

Bibliographic database of PACS-related articles from the SPIE literature

Science.gov (United States)

Shile, Peter E.; Freiermuth, Jennifer

1996-05-01

Publications of the International Society of Optical Engineering (SPIE) contain much of the relevant literature on Picture Archiving and Communications Systems (PACS) and related topics. In fact, many PACS-related articles indexed by the National Library of Medicine contain references to articles published by SPIE. Unfortunately, SPIE publications themselves are not indexed by the National Library of Medicine and thus can not be identified through Medline. The lack of a convenient mechanism for searching the SPIE literature is problematic for researchers in medical imaging. With the recent introduction on SPIE's Internet server of their Abstracts Online service and their In-CiteTM title and author searching software, the SPIE literature has become more accessible. However, the searching process is still a cumbersome and time consuming process, and it is not possible to perform key word searches of manuscript abstracts. In this paper we present results of our work on developing a mechanism to more thoroughly search SPIE publications for PACS-related articles.

CHARACTERIZING THE YOUNGEST HERSCHEL-DETECTED PROTOSTARS. I. ENVELOPE STRUCTURE REVEALED BY CARMA DUST CONTINUUM OBSERVATIONS

International Nuclear Information System (INIS)

Tobin, John J.; Stutz, Amelia M.; Henning, Thomas; Ragan, Sarah E.; Megeath, S. Thomas; Fischer, William J.; Ali, Babar; Stanke, Thomas; Manoj, P.; Calvet, Nuria; Hartmann, Lee

2015-01-01

We present Combined Array for Research in Millimeter-wave Astronomy 2.9 mm dust continuum emission observations of a sample of 14 Herschel-detected Class 0 protostars in the Orion A and B molecular clouds, drawn from the PACS Bright Red Sources (PBRS) sample. These objects are characterized by very red 24-70 μm colors and prominent submillimeter emission, suggesting that they are very young Class 0 protostars embedded in dense envelopes. We detect all of the PBRS in 2.9 mm continuum emission and emission from four protostars and one starless core in the fields toward the PBRS; we also report one new PBRS source. The ratio of 2.9 mm luminosity to bolometric luminosity is higher by a factor of ∼5 on average, compared to other well-studied protostars in the Perseus and Ophiuchus clouds. The 2.9 mm visibility amplitudes for 6 of the 14 PBRS are very flat as a function of uv distance, with more than 50% of the source emission arising from radii <1500 AU. These flat visibility amplitudes are most consistent with spherically symmetric envelope density profiles with ρ ∝ R –2.5 . Alternatively, there could be a massive unresolved structure like a disk or a high-density inner envelope departing from a smooth power law. The large amount of mass on scales <1500 AU (implying high average central densities) leads us to suggest that that the PBRS with flat visibility amplitude profiles are the youngest PBRS and may be undergoing a brief phase of high mass infall/accretion and are possibly among the youngest Class 0 protostars. The PBRS with more rapidly declining visibility amplitudes still have large envelope masses, but could be slightly more evolved

Effect of Ambipolar Diffusion on Ion Abundances in Contracting Protostellar Cores

Science.gov (United States)

Ciolek, Glenn E.; Mouschovias, Telemachos Ch.

1998-09-01

Numerical simulations and analytical solutions have established that ambipolar diffusion can reduce the dust-to-gas ratio in magnetically and thermally supercritical cores during the epoch of core formation. We study the effect that this has on the ion chemistry in contracting protostellar cores and present a simplified analytical method that allows one to calculate the ion power-law exponent k (≡d ln ni/d ln nn, where ni and nn are the ion and neutral densities, respectively) as a function of core density. We find that, as in earlier numerical simulations, no single value of k can adequately describe the ion abundance for nn 1/2 during the core formation epoch (densities principle, to determine whether ambipolar diffusion is responsible for core formation in interstellar molecular clouds. For densities >>105 cm-3, k is generally <<1/2.

Performance enhancement with powdered activated carbon (PAC) addition in a membrane bioreactor (MBR) treating distillery effluent

International Nuclear Information System (INIS)

Satyawali, Yamini; Balakrishnan, Malini

2009-01-01

This work investigated the effect of powdered activated carbon (PAC) addition on the operation of a membrane bioreactor (MBR) treating sugarcane molasses based distillery wastewater (spentwash). The 8 L reactor was equipped with a submerged 30 μm nylon mesh filter with 0.05 m 2 filtration area. Detailed characterization of the commercial wood charcoal based PAC was performed before using it in the MBR. The MBR was operated over 200 days at organic loading rates (OLRs) varying from 4.2 to 6.9 kg m -3 d -1 . PAC addition controlled the reactor foaming during start up and enhanced the critical flux by around 23%; it also prolonged the duration between filter cleaning. Operation at higher loading rates was possible and for a given OLR, the chemical oxygen demand (COD) removal was higher with PAC addition. However, biodegradation in the reactor was limited and the high molecular weight compounds were not affected by PAC supplementation. The functional groups on PAC appear to interact with the polysaccharide portion of the sludge, which may reduce its propensity to interact with the nylon mesh.

Simulation of California's Major Reservoirs Outflow Using Data Mining Technique

Science.gov (United States)

Yang, T.; Gao, X.; Sorooshian, S.

2014-12-01

The reservoir's outflow is controlled by reservoir operators, which is different from the upstream inflow. The outflow is more important than the reservoir's inflow for the downstream water users. In order to simulate the complicated reservoir operation and extract the outflow decision making patterns for California's 12 major reservoirs, we build a data-driven, computer-based ("artificial intelligent") reservoir decision making tool, using decision regression and classification tree approach. This is a well-developed statistical and graphical modeling methodology in the field of data mining. A shuffled cross validation approach is also employed to extract the outflow decision making patterns and rules based on the selected decision variables (inflow amount, precipitation, timing, water type year etc.). To show the accuracy of the model, a verification study is carried out comparing the model-generated outflow decisions ("artificial intelligent" decisions) with that made by reservoir operators (human decisions). The simulation results show that the machine-generated outflow decisions are very similar to the real reservoir operators' decisions. This conclusion is based on statistical evaluations using the Nash-Sutcliffe test. The proposed model is able to detect the most influential variables and their weights when the reservoir operators make an outflow decision. While the proposed approach was firstly applied and tested on California's 12 major reservoirs, the method is universally adaptable to other reservoir systems.

The effects of PACS on radiographer's work practice

International Nuclear Information System (INIS)

Larsson, W.; Aspelin, P.; Bergquist, M.; Hillergard, K.; Jacobsson, B.; Lindskoeld, L.; Wallberg, J.; Lundberg, N.

2007-01-01

This paper identifies and analyses the effects of picture archiving and communication systems (PACS) on radiographers' work practice. It shows that the introduction of PACS did not simply entail the transfer of data and information from the analogue world to the digital world, but it also led to the introduction of new ways of communicating, and new activities and responsibilities on the part of radiography staff. Radiographers are called upon to work increasingly independently, and individual practitioners require higher levels of professional expertise. In all, this paper demonstrates that new technical solutions sometimes lead to substantial changes in responsibilities in work. In this example, the radiographers' work practice has become more highly scientific and they are enjoying a higher level of prestige

Neutral and Ionized Hydrides in Star-forming Regions. Observations with Herschel/HIFI

DEFF Research Database (Denmark)

O. Benz, Arnold; Bruderer, Simon; F. van Dishoeck, Ewine

2013-01-01

of OH, CH, NH, SH and their ions OH+, CH+, NH+, SH+, H2O+, and H3O+ were observed in star-forming regions by the HIFI spectrometer onboard the Herschel Space Observatory. Molecular column densities are derived from observed ground-state lines, models, or rotational diagrams. We report here on two...

Sphere-pac fuel development program. First semi-annual progress report, October 1979-March 1980

International Nuclear Information System (INIS)

Felt, R.E.

1980-05-01

Development of processes by Exxon Nuclear Company, Inc. for fabricating spherical particle nuclear fuel (sphere-pac) during October 1979 through March 1980 is reported. The program surveyed available technology to develop an initial flowsheet as a design basis for process development. An 0.1 ton/day pilot plant was built to develop and demonstrate the fabrication of sphere-pac fuel. Process and equipment efforts have been directed towards the demonstration of processes and equipment necessary to fabricate sphere-pac fuel on a commercial scale

Two separate outflows in the dual supermassive black hole system NGC 6240.

Science.gov (United States)

Müller-Sánchez, F; Nevin, R; Comerford, J M; Davies, R I; Privon, G C; Treister, E

2018-04-01

Theoretical models and numerical simulations have established a framework of galaxy evolution in which galaxies merge and create dual supermassive black holes (with separations of one to ten kiloparsecs), which eventually sink into the centre of the merger remnant, emit gravitational waves and coalesce. The merger also triggers star formation and supermassive black hole growth, and gas outflows regulate the stellar content 1-3 . Although this theoretical picture is supported by recent observations of starburst-driven and supermassive black hole-driven outflows 4-6 , it remains unclear how these outflows interact with the interstellar medium. Furthermore, the relative contributions of star formation and black hole activity to galactic feedback remain unknown 7-9 . Here we report observations of dual outflows in the central region of the prototypical merger NGC 6240. We find a black-hole-driven outflow of [O III] to the northeast and a starburst-driven outflow of Hα to the northwest. The orientations and positions of the outflows allow us to isolate them spatially and study their properties independently. We estimate mass outflow rates of 10 and 75 solar masses per year for the Hα bubble and the [O III] cone, respectively. Their combined mass outflow is comparable to the star formation rate 10 , suggesting that negative feedback on star formation is occurring.

Merits of usability testing for PACS selection

NARCIS (Netherlands)

Jorritsma, Wiard; Cnossen, Fokie; van Ooijen, Peter M. A.

Objectives: To compare the usability of different Picture Archiving and Communication System (PACS) workstations, determine whether a usability test has added value with respect to the traditional way of comparing PACSs based on functional requirements, and to evaluate the appropriateness of a

Internationalization of healthcare applications: a generic approach for PACS workstations.

Science.gov (United States)

Hussein, R; Engelmann, U; Schroeter, A; Meinzer, H P

2004-01-01

Along with the revolution of information technology and the increasing use of computers world-wide, software providers recognize the emerging need for internationalized, or global, software applications. The importance of internationalization comes from its benefits such as addressing a broader audience, making the software applications more accessible, easier to use, more flexible to support and providing users with more consistent information. In addition, some governmental agencies, e.g., in Spain, accept only fully localized software. Although the healthcare communication standards, namely, Digital Imaging and Communication in Medicine (DICOM) and Health Level Seven (HL7) support wide areas of internationalization, most of the implementers are still protective about supporting the complex languages. This paper describes a generic internationalization approach for Picture Archiving and Communication System (PACS) workstations. The Unicode standard is used to internationalize the application user interface. An encoding converter was developed to encode and decode the data between the rendering module (in Unicode encoding) and the DICOM data (in ISO 8859 encoding). An integration gateway was required to integrate the internationalized PACS components with the different PACS installations. To introduce a pragmatic example, the described approach was applied to the CHILI PACS workstation. The approach has enabled the application to handle the different internationalization aspects transparently, such as supporting complex languages, switching between different languages at runtime, and supporting multilingual clinical reports. In the healthcare enterprises, internationalized applications play an essential role in supporting a seamless flow of information between the heterogeneous multivendor information systems.

Refinement of atomic position in purely ionic materials using PAC spectroscopy

International Nuclear Information System (INIS)

Eslami, E.; Saramad, S.; Moussavi-Zarandi, A.

2000-01-01

In pure ionic solids by means of electric field gradients at substitutional radioactive probe the positions of all atoms in the unit cell can be determined by PAC method with an accuracy of 0.3 Pm which is typically 5 times better than the data available from X ray and neutron diffraction experiments. In the case of oxides where to our knowledge no diffraction analysis exists, the PAC analysis predicts the atomic parameters

DIGIT survey of far-infrared lines from protoplanetary discs : II. CO

NARCIS (Netherlands)

Meeus, Gwendolyn; Salyk, Colette; Bruderer, Simon; Fedele, Davide; Maaskant, Koen; Evans, Neal J.; van Dishoeck, Ewine F.; Montesinos, Benjamin; Herczeg, Greg; Bouwman, Jeroen; Green, Joel D.; Dominik, Carsten; Henning, Thomas; Vicente, Silvia

2013-01-01

CO is an important component of a protoplanetary disc as it is one of the most abundant gas phase species. Furthermore, observations of CO transitions can be used as a diagnostic of the gas, tracing conditions in both the inner and outer disc. We present Herschel/PACS spectroscopy of a sample of 22

DIGIT survey of far-infrared lines from protoplanetary discs. II. CO

NARCIS (Netherlands)

Meeus, G.; Salyk, C.; Bruderer, S.; Fedele, D.; Maaskant, K.M.; Evans, N.; Dishoeck, van E.F.; Montesinos, B.; Herczeg, G.; Bouwman, J.; Green, J.; Dominik, C.; Henning, T.; Vicente, S.

2013-01-01

CO is an important component of a protoplanetary disc as it is one of the most abundant gas phase species. Furthermore, observations of CO transitions can be used as a diagnostic of the gas, tracing conditions in both the inner and outer disc. We present Herschel/PACS spectroscopy of a sample of 22

In vivo biological evaluation of 131I radiolabeled-paclitaxel glucuronide (131I-PAC-G)

International Nuclear Information System (INIS)

Aslan, O.; Biber Muftuler, F.Z.; Yurt Kilcar, A.; Ichedef, C.; Unak, P.

2012-01-01

Paclitaxel (PAC) is a natural occurring diterpene alkoloid originally isolated from the bark of Taxus Brevifolia. It is one of the most important antitumor agents for clinical treatment of ovarian, breast non-small cell lung and prostate cancers. It is known that these types of cancer cells have high β-glucuronidase enzyme which can catalyze the hydrolysis of glucuronides. This is why the synthesis compounds which undergo glucuronidation come into question in the imaging and therapy of these cancer cells. The aim of current study is conjugation of glucuronic acid (G) to the starting substance PAC, labeling with 131 I and to perform its in vivo biological evaluation. Glucuronic acid derived paclitaxel compound [paclitaxel-glucuronide (PAC-G)] was labeled with 131 I using iodogen method. According to thin layer radio chromatography (TLRC) method, the radiochemical yield of 131 I-PAC-G was 84.30 ± 7.40% (n=10). The biodistribution of 131 I-PAC-G in healthy female and male Wistar Albino rats has been investigated. Imaging studies on male Balb-C mice were performed by using the Kodak FX PRO in vivo Imaging System. The range of the breast/blood, breast/muscle; ovary/blood, ovary/muscle ratios is approximately between 1.29 and 11.34 in 240 min, and between 0.71 and 8.24 in 240 min for female rats. The prostate/blood and prostate/muscle ratio is between 1.94 and 6.95 in 30 min for male rats. All these experimental studies indicate that 131 I-PAC-G may potentially be used in breast, ovary and prostate tissues as an imaging agent. Also it is thought that 131 I-PAC-G bears a therapy potential because of the 131 I radionuclide and can be improved with further investigations. (orig.)

Introduction to PAC/PAD

International Nuclear Information System (INIS)

Mahnke, H.E.

1988-01-01

Both methods, Perturbed Angular Correlation (PAC) utilizing radioactive probes and Perturbed Angular Distribution (PAD) following nuclear reactions measure hyperfine interaction parameters and allow to study magnetism on a rather local scale. While both techniques are based on the same theory the underlying concepts are quite different. Examples on local moments, influence of the nearest-neighbor to the magnetic field in ferromagnets, knight shift in nonmagnetic materials, and magnetism in high-temperature superconductors and related oxides illustrate the recent developments within the methods and the improvements in their sensitivity and resolution. (orig.)

Cosmic ray driven outflows in an ultraluminous galaxy

Science.gov (United States)

Fujita, Akimi; Mac Low, Mordecai-Mark

2018-06-01

In models of galaxy formation, feedback driven both by supernova (SN) and active galactic nucleus is not efficient enough to quench star formation in massive galaxies. Models of smaller galaxies have suggested that cosmic rays (CRs) play a major role in expelling material from the star-forming regions by diffusing SN energy to the lower density outskirts. We therefore run gas dynamical simulations of galactic outflows from a galaxy contained in a halo with 5 × 1012 M⊙ that resembles a local ultraluminous galaxy, including both SN thermal energy and a treatment of CRs using the same diffusion approximation as Salem & Bryan. We find that CR pressure drives a low-density bubble beyond the edge of the shell swept up by thermal pressure, but the main bubble driven by SN thermal pressure overtakes it later, which creates a large-scale biconical outflow. CRs diffusing into the disc are unable to entrain its gas in the outflows, yielding a mass-loading rate of only ˜ 0.1 per cent with varied CR diffusion coefficients. We find no significant difference in mass-loading rates in SN-driven outflows with or without CR pressure. Our simulations strongly suggest that it is hard to drive a heavily mass-loaded outflow with CRs from a massive halo potential, although more distributed star formation could lead to a different result.