An H I interstellar bubble surrounding WR 85 and RCW 118

We analyse the distribution of the interstellar matter in the environs of the Wolf-Rayet star LSS 3982 (= WR 85, WN6+OB?) linked to the optical ring nebula RCW118. Our study is based on neutral hydrogen 21-cm line data belonging to the Southern Galactic Plane Survey (SGPS). The analysis of the H I data allowed the identification of a neutral hydrogen interstellar bubble related to WR85 and the 25-arcmin-diameter ring nebula RCW 118. The H I bubble was detected at a systemic velocity of -21.5 km s-1, corresponding to a kinematical distance of 2.8 ± 1.1 kpc, compatible with the stellar distance. The neutral structure is about 25 arcmin in radius or 21 ± 8 pc, and is expanding at 9 ± 2 km s-1. The associated ionized and neutral masses amount to 3000 M⊙ . The carbon monoxide (CO) emission distribution depicts a region lacking CO coincident in position and velocity with the H I structure. The 9.3-arcmin-diameter inner optical nebula appears to be related to the approaching part of the neutral atomic shell. The H I void and shell are the neutral gas counterparts of the optical bubble and have very probably originated in the action of the strong stellar wind of the central star during the O-type and WR phases on the surrounding interstellar medium. The H I bubble appears to be in the momentum conserving stage.Facultad de Ciencias Astronómicas y GeofísicasInstituto Argentino de Radioastronomí

The IRAS 08589-4714 star-forming region

We present an analysis of the IRAS 08589-4714 star-forming region. Thisregion harbors candidate young stellar objects identified in the WISEand Herschel images using color index criteria and spectral energydistributions (SEDs). The SEDs of some of the infrared sources and the70 microns radial intensity profile of the brightest source (IRS 1) aremodeled from Herschel fluxes using the one-dimensional radiativetransfer DUSTY code. For these objects, we estimate the envelope masses,sizes, densities, and luminosities which suggest that they are veryyoung, massive and luminous objects at early stages of the formationprocess. Color-color diagrams in the bands of WISE and 2MASS are used toidentify potential young objects in the region. Those identified in thebands of WISE would be contaminated by the emission of PAHs. We use theemission distribution in the infrared at 70 and 160 microns, to estimatethe dust temperature gradient. This suggests that the nearby massivestar-forming region RCW 38, located ~ 10 pc of the IRAS source positionmay be contributing to the photodissociation of the molecular gas and tothe heating of the interstellar dust in the environs of the IRAS source.Fil: Saldaño, Hugo Pablo. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vasquez, Javier. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaFil: Gómez, M.. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cappa, Cristina Elisabeth. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaFil: Duronea, Nicolas Urbano. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Rubio, M.. Universidad de Chile; Chil

The IRAS 08589-4714 star-forming region

We present an analysis of the IRAS 08589-4714 star-forming region. Thisregion harbors candidate young stellar objects identified in the WISEand Herschel images using color index criteria and spectral energydistributions (SEDs). The SEDs of some of the infrared sources and the70 microns radial intensity profile of the brightest source (IRS 1) aremodeled from Herschel fluxes using the one-dimensional radiativetransfer DUSTY code. For these objects, we estimate the envelope masses,sizes, densities, and luminosities which suggest that they are veryyoung, massive and luminous objects at early stages of the formationprocess. Color-color diagrams in the bands of WISE and 2MASS are used toidentify potential young objects in the region. Those identified in thebands of WISE would be contaminated by the emission of PAHs. We use theemission distribution in the infrared at 70 and 160 microns, to estimatethe dust temperature gradient. This suggests that the nearby massivestar-forming region RCW 38, located ~ 10 pc of the IRAS source positionmay be contributing to the photodissociation of the molecular gas and tothe heating of the interstellar dust in the environs of the IRAS source.Instituto Argentino de RadioastronomíaFacultad de Ciencias Astronómicas y Geofísica

Molecular gas in the star-forming region IRAS 08589-4714

Aims. We present an analysis of the region IRAS 08589-4714 with the aim of characterizing the molecular environment. Methods. We observed the 12CO(3-2), 13CO(3-2), C18O(3-2), HCO+(3-2), and HCN(3-2) molecular lines in a region of 150″ × 150″, centered on the IRAS source, to analyze the distribution and characteristics of the molecular gas linked to the IRAS source. Results. The molecular gas distribution reveals a molecular clump that is coincident with IRAS 08589-4714 and with a dust clump detected at 1.2 mm. The molecular clump is 0.45 pc in radius and its mass and H2 volume density are 310 M⊙ and 1.2 × 104 cm-3, respectively. Two overdensities were identified within the clump in HCN(3-2) and HCO+(3-2) lines. A comparison of the LTE and virial masses suggests that the clump is collapsing in regions that harbor young stellar objects. An analysis of the molecular lines suggests that they are driving molecular outflows.Facultad de Ciencias Astronómicas y GeofísicasInstituto Argentino de Radioastronomí

Efficient Integral Equation Approach for the Modelling of Glide-Symmetric Structures

For the design of advanced microwave and antenna components, efficient and accurate electromagnetic methods are required. In this work, we present a technique to fast simulate mirror- and glide-symmetric periodic structures. More concretely, a novel Green’s function is proposed which allows to reduce the computational domain to one half of the unit cell. Full dispersion diagrams are computed for metallic glide- and mirror-symmetric structures with three stages of mesh refinement. The results converge with the meshing and agree well with conventional eigenmode analyses

An H I interstellar bubble surrounding WR 85 and RCW 118

We analyse the distribution of the interstellar matter in the environs of the Wolf-Rayet star LSS 3982 (= WR 85, WN6+OB?) linked to the optical ring nebula RCW118. Our study is based on neutral hydrogen 21-cm line data belonging to the Southern Galactic Plane Survey (SGPS). The analysis of the H I data allowed the identification of a neutral hydrogen interstellar bubble related to WR85 and the 25-arcmin-diameter ring nebula RCW 118. The H I bubble was detected at a systemic velocity of -21.5 km s-1, corresponding to a kinematical distance of 2.8 ± 1.1 kpc, compatible with the stellar distance. The neutral structure is about 25 arcmin in radius or 21 ± 8 pc, and is expanding at 9 ± 2 km s-1. The associated ionized and neutral masses amount to 3000 M⊙ . The carbon monoxide (CO) emission distribution depicts a region lacking CO coincident in position and velocity with the H I structure. The 9.3-arcmin-diameter inner optical nebula appears to be related to the approaching part of the neutral atomic shell. The H I void and shell are the neutral gas counterparts of the optical bubble and have very probably originated in the action of the strong stellar wind of the central star during the O-type and WR phases on the surrounding interstellar medium. The H I bubble appears to be in the momentum conserving stage.Facultad de Ciencias Astronómicas y GeofísicasInstituto Argentino de Radioastronomí

A submillimeter study of the IR dust bubble S 21 and its environs

Based on the molecular emission in the 12CO(2-1) and 13CO(2-1) lines, and on the continuum emission in the MIR and FIR towards the S 21 IR dust bubble, we analyze the physical characteristics of the gas and dust linked to the nebula and the presence of young stellar objects (YSOs) in its environs. The line emission reveals a clumpy molecular shell, 1.4 pc in radius, encircling S 21. The total molecular mass in the shell amounts to 2900 M⊙ and the original ambient density, 2.1 ×10 3 cm − 3 , indicating that the bubble is evolving in a high density interstellar medium. The image at 24 µm shows warm dust inside the bubble, while the emission in the range 250 to 870 µm reveals cold dust in its outskirts, coincident with the molecular gas. The detection of radio continuum emission indicates that the bubble is a compact Hii region. A search for YSOs using photometric criteria allowed to identify many candidates projected onto the molecular clumps. We analize if the collect and collapse process has triggered a new generation of stars.Basados en la emisión molecular en las líneas 12CO(2-1) y 13CO(2-1), y en la emisión en el continuo en el mediano y lejano infrarrojo hacia la burbuja S 21, analizamos las características físicas del gas y polvo asociado con S 21 y la presencia de objetos estelares jóvenes (YSOs) en su entorno. La emisión molecular revela una cáscara grumosa de 1.4 pc de radio rodeando a S 21. Su masa molecular es de 2900 M⊙ y la densidad ambiental original en la región, 2.1 ×10 3 cm − 3 , lo que indica que la burbuja evoluciona en un medio de alta densidad. La imagen a 24 µ m muestra polvo tibio dentro de la burbuja, mientras que la emisión en el rango 250 a 870 µm revela que hay polvo frío en la vecindad, coincidente con el gas molecular. La detección de emisión en el continuo de radio indica que S 21 es una región Hii compacta. Una búsqueda de YSOs utilizando criterios fotométricos permitió identificar muchos candidatos coincidentes con los grumos moleculares. Se analiza si el proceso de collect and collapse ha dado origen a una nueva generación de estrellas.Fil: Cappa, Cristina Elisabeth. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Duronea, Nicolas Urbano. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Vasquez, Javier. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Rubio, M.. Universidad de Chile. Facultad de Ciencias Fisicas y Matematicas; ChileFil: Firpo, V.. Universidad de la Serena; ChileFil: López Caraballo, C. H.. Universidad Católica de Chile; ChileFil: Borissova, J.. Universidad de Valparaiso; Chil