Browsing by Author "Zavagno, A."
Now showing 1 - 4 of 4
Results Per Page
Sort Options
- ItemDistance of Hi-GAL sources(Les Ulis : EDP Sciences, 2021) Mège, P.; Russeil, D.; Zavagno, A.; Elia, D.; Molinari, S.; Brunt, C.M.; Butora, R.; Cambresy, L.; Di Giorgio, A.M.; Fenouillet, T.; Fukui, Y.; Lambert, J.C.; Makai, Z.; Merello, M.; Meunier, J.C.; Molinaro, M.; Moreau, C.; Pezzuto, S.; Poulin, Y.; Schisano, E.; Schuller, F.Aims. Distances are key to determining the physical properties of sources. In the Galaxy, large (> 10 000) homogeneous samples of sources for which distance are available, covering the whole Galactic distance range, are still missing. Here we present a catalog of velocity and distance for a large sample (> 100 000) of Hi-GAL compact sources. Methods. We developed a fully automatic Python package to extract the velocity and determine the distance. To assign a velocity to a Hi-GAL compact source, the code uses all the available spectroscopic data complemented by a morphological analysis. Once the velocity is determined, if no stellar or maser parallax distance is known, the kinematic distance is calculated and the distance ambiguity (for sources located inside the Solar circle) is solved with the H I self-absorption method or from distance-extinction data. Results. Among the 150 223 compact sources of the Hi-GAL catalog, we obtained a distance for 124 069 sources for the 5σ catalog (and 128 351 sources for the 3σ catalog), where σ represents the noise level of each molecular spectrum used for the line detections made at 5σ and 3σ to produce the respective catalogs. © P. Mège et al. 2021.
- ItemProbing the structure of a massive filament: ArTéMiS 350 and 450 μm mapping of the integral-shaped filament in Orion A(Les Ulis : EDP Sciences, 2021) Schuller, F.; André, Ph.; Shimajiri, Y.; Zavagno, A.; Peretto, N.; Arzoumanian, D.; Csengeri, T.; Könyves, V.; Palmeirim, P.; Pezzuto, S.; Rigby, A.; Roussel, H.; Ajeddig, H.; Dumaye, L.; P. Gallais, P.; Le Pennec, J.; Martignac, J.; Mattern, M.; Revéret, V.; Rodriguez, L.; Talvard, M.Context. The Orion molecular cloud is the closest region of high-mass star formation. It is an ideal target for investigating the detailed structure of massive star-forming filaments at high resolution and the relevance of the filament paradigm for the earliest stages of intermediate- to high-mass star formation. Aims. Within the Orion A molecular cloud, the integral-shaped filament (ISF) is a prominent, degree-long structure of dense gas and dust with clear signs of recent and ongoing high-mass star formation. Our aim is to characterise the structure of this massive filament at moderately high angular resolution (8′′ or ~0.016 pc) in order to measure the intrinsic width of the main filament, down to scales well below 0.1 pc, which has been identified as the characteristic width of filaments. Methods. We used the ArTéMiS bolometer camera at APEX to map a ~0.6 × 0.2 deg2 region covering OMC-1, OMC-2, and OMC-3 at 350 and 450 μm. We combined these data with Herschel-SPIRE maps to recover extended emission. The combined Herschel-ArTéMiS maps provide details on the distribution of dense cold material, with a high spatial dynamic range, from our 8′′ resolution up to the transverse angular size of the map, ~10-15′. By combining Herschel and ArTéMiS data at 160, 250, 350, and 450 μm, we constructed high-resolution temperature and H2 column density maps. We extracted radial intensity profiles from the column density map in several representative portions of the ISF, which we fitted with Gaussian and Plummer models to derive their intrinsic widths. We also compared the distribution of material traced by ArTéMiS with that seen in the higher-density tracer N2H+(1-0) that was recently observed with the ALMA interferometer. Results. All the radial profiles that we extracted show a clear deviation from a Gaussian, with evidence for an inner plateau that had not previously been seen clearly using Herschel-only data. We measure intrinsic half-power widths in the range 0.06-0.11 pc. This is significantly larger than the Gaussian widths measured for fibres seen in N2H+, which probably only traces the dense innermost regions of the large-scale filament. These half-power widths are within a factor of two of the value of ~0.1 pc found for a large sample of nearby filaments in various low-mass star-forming regions, which tends to indicate that the physical conditions governing the fragmentation of pre-stellar cores within transcritical or supercritical filaments are the same over a large range of masses per unit length. © F. Schuller et al. 2021.
- ItemThe role of Galactic HII regions in the formation of filaments : High-resolution submilimeter imaging of RCW 120 with ArTéMiS(Les Ulis : EDP Sciences, 2020) Zavagno, A.; André, Ph.; Schuller, F.; Peretto, N.; Shimajiri, Y.; Arzoumanian, D.; Csengeri, T.; Figueira, M.; Fuller, G.A.; Könyves, V.; Men’shchikov, A.; Palmeirim, P.; Roussel, H.; Russeil, D.; Schneider, N.; Zhang, S.Context. Massive stars and their associated ionized (H II) regions could play a key role in the formation and evolution of filaments that host star formation. However, the properties of filaments that interact with H II regions are still poorly known. Aims. To investigate the impact of H II regions on the formation of filaments, we imaged the Galactic H II region RCW 120 and its surroundings where active star formation takes place and where the role of ionization feedback on the star formation process has already been studied. Methods. We used the large-format bolometer camera ArTéMiS on the APEX telescope and combined the high-resolution ArTéMiS data at 350 and 450 μm with Herschel-SPIRE/HOBYS data at 350 and 500 μm to ensure good sensitivity to a broad range of spatial scales. This allowed us to study the dense gas distribution around RCW 120 with a resolution of 8′′ or 0.05 pc at a distance of 1.34 kpc. Results. Our study allows us to trace the median radial intensity profile of the dense shell of RCW 120. This profile is asymmetric, indicating a clear compression from the H II region on the inner part of the shell. The profile is observed to be similarly asymmetric on both lateral sides of the shell, indicating a homogeneous compression over the surface. On the contrary, the profile analysis of a radial filament associated with the shell, but located outside of it, reveals a symmetric profile, suggesting that the compression from the ionized region is limited to the dense shell. The mean intensity profile of the internal part of the shell is well fitted by a Plummer-like profile with a deconvolved Gaussian full width at half maximum of 0.09 pc, as observed for filaments in low-mass star-forming regions. Conclusions. Using ArTéMiS data combined with Herschel-SPIRE data, we found evidence for compression from the inner part of the RCW 120 ionized region on the surrounding dense shell. This compression is accompanied with a significant (factor 5) increase of the local column density. This study suggests that compression exerted by H II regions may play a key role in the formation of filaments and may further act on their hosted star formation. ArTéMiS data also suggest that RCW 120 might be a 3D ring, rather than a spherical structure.
- ItemThe SEDIGISM survey: first data release and overview of the Galactic structure(Oxford : Oxford Univ. Press, 2021) Schuller, F.; Urquhart, J.S.; Csengeri, T.; Colombo, D.; Duarte-Cabral, A.; Mattern, M.; Ginsburg, A.; Pettitt, A.R.; Wyrowski, F.; Anderson, L.; Azagra, F.; Barnes, P.; Beltran, M.; Beuther, H.; Billington, S.; Bronfman, L.; Cesaroni, R.; Dobbs, C.; Eden, D.; Lee, M.-Y.; Medina, S.-N.X.; Menten, K.M.; Moore, T.; Montenegro-Montes, F.M.; Ragan, S.; Rigby, A.; Riener, M.; Russeil, D.; Schisano, E.; Sanchez-Monge, A.; Traficante, A.; Zavagno, A.; Agurto, C.; Bontemps, S.; Finger, R.; Giannetti, A.; Gonzalez, E.; Hernandez, A.K.; Henning, T.; Kainulainen, J.; Kauffmann, J.; Leurini, S.; Lopez, S.; Mac-Auliffe, F.; Mazumdar, P.; Molinari, S.; Motte, F.; Muller, E.; Nguyen-Luong, Q.; Parra, R.; Perez-Beaupuits, J.-P.; Schilke, P.; Schneider, N.; Suri, S.; Testi, L.; Torstensson, K.; Veena, V.S.; Venegas, P.; Wang, K.; Wienen, M.The SEDIGISM (Structure, Excitation and Dynamics of the Inner Galactic Interstellar Medium) survey used the APEX telescope to map 84 deg2 of the Galactic plane between ℓ = −60° and +31° in several molecular transitions, including 13CO (2 – 1) and C18O (2 – 1), thus probing the moderately dense (∼103 cm−3) component of the interstellar medium. With an angular resolution of 30 arcsec and a typical 1σ sensitivity of 0.8–1.0 K at 0.25 km s−1 velocity resolution, it gives access to a wide range of structures, from individual star-forming clumps to giant molecular clouds and complexes. The coverage includes a good fraction of the first and fourth Galactic quadrants, allowing us to constrain the large-scale distribution of cold molecular gas in the inner Galaxy. In this paper, we provide an updated overview of the full survey and the data reduction procedures used. We also assess the quality of these data and describe the data products that are being made publicly available as part of this First Data Release (DR1). We present integrated maps and position–velocity maps of the molecular gas and use these to investigate the correlation between the molecular gas and the large-scale structural features of the Milky Way such as the spiral arms, Galactic bar and Galactic Centre. We find that approximately 60 per cent of the molecular gas is associated with the spiral arms and these appear as strong intensity peaks in the derived Galactocentric distribution. We also find strong peaks in intensity at specific longitudes that correspond to the Galactic Centre and well-known star-forming complexes, revealing that the 13CO emission is concentrated in a small number of complexes rather than evenly distributed along spiral arms.