MAMBO mapping of Spitzer c2d small clouds and cores

Kauffmann, Jens; Bertoldi, F.; Bourke, Tyler L.; Evans, Neal J.; Lee, C. W.

doi:10.1051/0004-6361:200809481

Cited by 648 publications

(709 citation statements)

References 103 publications

(210 reference statements)

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“…Models of dust grains with thick ice mantles give an absorption coefficient, κ, of 1.85 cm 2 /g at 870 μm at a gas density n(H) = 10 6 cm −3 (Ossenkopf & Henning 1994). We estimated the H 2 column density per the relation (Kauffmann et al 2008) N(H 2 ) = 2.03 × 10 16 S 40 870 μm λ 3 exp 1.44 × 10 4…”

Section: Submillimeter Flux and Nhmentioning

confidence: 99%

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Ammonia from cold high-mass clumps discovered in the inner Galactic disk by the ATLASGAL survey

Wienen

Wyrowski

Schüller

et al. 2012

A&A

220

368

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Context. The APEX Telescope Large Area Survey: the GALaxy (ATLASGAL) is an unbiased continuum survey of the inner Galactic disk at 870 μm. It covers ±60 • in Galactic longitude and aims to find all massive clumps at various stages of high-mass star formation in the inner Galaxy, particularly the earliest evolutionary phases. Aims. We aim to determine properties such as the gas kinetic temperature and dynamics of new massive cold clumps found by ATLASGAL. Most importantly, we derived their kinematical distances from the measured line velocities. Methods. We observed the ammonia (J, K) = (1, 1) to (3, 3) inversion transitions toward 862 clumps of a flux-limited sample of submm clumps detected by ATLASGAL and extracted 13 CO (1−0) spectra from the Galactic Ring Survey (GRS). We determined distances for a subsample located at the tangential points (71 sources) and for 277 clumps whose near/far distance ambiguity is resolved. Results. Most ATLASGAL clumps are cold with rotational temperatures from 10−30 K with a median of 17 K. They have a wide range of NH 3 linewidths (1−7 km s −1 ) with 1.9 km s −1 as median, which by far exceeds the thermal linewidth, as well as a broad distribution of high column densities from 10 14 to 10 16 cm −2 (median of 2 × 10 15 cm −2 ) with an NH 3 abundance in the range of 5 to 30 × 10 −8 . ATLASGAL sources are massive, > ∼ 100 M , and a fraction of clumps with a broad linewidth is in virial equilibrium. We found an enhancement of clumps at Galactocentric radii of 4.5 and 6 kpc. The comparison of the NH 3 lines as high-density probes with the GRS 13 CO emission as low-density envelope tracer yields broader linewidths for 13 CO than for NH 3 . The small differences in derived clump velocities between NH 3 (representing dense core material) and 13 CO (representing more diffuse molecular cloud gas) suggests that the cores are essentially at rest relative to the surrounding giant molecular cloud. Conclusions. The high detection rate (87%) confirms ammonia as an excellent probe of the molecular content of the massive, cold clumps revealed by ATLASGAL. A clear trend of increasing rotational temperatures and linewidths with evolutionary stage is seen for source samples ranging from 24 μm dark clumps to clumps with embedded HII regions. The survey provides the largest ammonia sample of high-mass star forming clumps and thus presents an important repository for the characterization of statistical properties of the clumps and the selection of subsamples for detailed, high-resolution follow-up studies.

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Section: Submillimeter Flux and Nhmentioning

confidence: 99%

“…The gas mass of a source obtained from the dust is (Kauffmann et al 2008) M gas = 1.2 × 10 −14 S 40 870 μm λ 3 d 2 exp 1.44 × 10 4…”

Section: Virial Masses and Gas Massesmentioning

confidence: 99%

Ammonia from cold high-mass clumps discovered in the inner Galactic disk by the ATLASGAL survey

Wienen

Wyrowski

Schüller

et al. 2012

A&A

220

368

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“…S ν is the flux density, Ω is the solid angle subtended by the beam, κ ν is the dust opacity at frequency ν (the absorption cross-section for radiation per unit mass of gas), µ H 2 = 2.8 is the molecular weight per hydrogen molecule (Kauffmann et al 2008), m H is the mass of the hydrogen atom and N H 2 is the molecular hydro-gen column density. The dust opacity can be approximated by a power-law at mm-wavelengths (Hildebrand 1983):…”

Section: Theoretical Backgroundmentioning

confidence: 99%

Search for grain growth toward the center of L1544

Chacón-Tanarro

Caselli

Bizzocchi

et al. 2017

A&A

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In dense and cold molecular clouds dust grains are surrounded by thick icy mantles. It is however not clear if dust growth and coagulation take place before the switch-on of a protostar. This is an important issue, as the presence of large grains may affect the chemical structure of dense cloud cores, including the dynamically important ionization fraction, and the future evolution of solids in protoplanetary disks. To study this further, we focus on L1544, one of the most centrally concentrated pre-stellar cores on the verge of star formation, and with a well-known physical structure. We observed L1544 at 1.2 and 2 mm using NIKA, a new receiver at the IRAM 30 m telescope, and we used data from the Herschel Space Observatory archive. We find no evidence of grain growth towards the center of L1544 at the available angular resolution. Therefore, we conclude that single dish observations do not allow us to investigate grain growth toward the pre-stellar core L1544 and high sensitivity interferometer observations are needed. We predict that dust grains can grow to 200 µm in size toward the central ∼300 au of L1544. This will imply a dust opacity change by a factor of ∼2.5 at 1.2 mm, which can be detected using the Atacama Large Millimeter and submillimeter Array (ALMA) at different wavelengths and with an angular resolution of 2 .

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“…We adopted the solar abundances for hydrogen, helium, and heavier elements, i.e., their mass fractions were taken to be 0.71, 0.27, and 0.02 of the total mass of all elements, respectively. This corresponds to a helium to hydrogen abundance ratio of about 0.10 and mean molecular weight per H 2 molecule of μ H 2 2.82 (Kauffmann et al 2008; Appendix A.1 therein). The 870-μm dust mass absorption (or emission) coefficient, i.e., dust opacity per unit dust mass was taken to be 1.38 cm 2 g −1 .…”

Section: Dust Temperature and H 2 Column Density Mapsmentioning

confidence: 99%

SABOCA 350-μm and LABOCA 870-μm dust continuum imaging of IRAS 05399-0121: mapping the dust properties of a pre- and protostellar core system

Miettinen

Offner

2013

A&A

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Context. Thermal emission from dust provides a valuable tool for determining important physical properties of the dense structures within molecular clouds. Aims. We attempt to map the distributions of dust temperature and H 2 column density of IRAS 05399-0121/SMM 1, which is a dense double-core system in Orion B9. We also search for substructures within the cores through high-resolution submillimetre imaging. Methods. The source was mapped with APEX/SABOCA at 350 μm. We combined these data with our previous LABOCA 870-μm data. The spatial resolution of the new SABOCA image, ∼3400 AU, is about 2.6 times better than provided by LABOCA, and is therefore well-suited to our purposes. We also make use of the Spitzer infrared observations to characterise the star-formation activity in the source. Results. The filamentary source remains a double-core system on the 3400 AU scale probed here, and the projected separation between IRAS 05399 and SMM 1 is 0.14 pc. The temperature map reveals warm spots towards IRAS 05399 and the southeastern tip of the source. Both IRAS 05399 and SMM 1 stand out as peaks in the column density map. A simple analysis suggests that the density profile has the form ∼r −(2.3 +2.2 −0.9 ) , as determined at the position of SMM 1. The broadband spectral energy distribution of IRAS 05399 suggests that it is near the Stage 0/I borderline. A visual inspection of the Spitzer/IRAC images provides hints of a quadrupolar-like jet morphology around IRAS 05399, supporting the possibility that it is a binary system. Conclusions. The source splitting into two subcores along the long axis can be explained by cylindrical Jeans-type fragmentation, but the steepness of the density profile is shallower than what is expected for an isothermal cylinder. The difference between the evolutionary stages of IRAS 05399 (protostellar) and SMM 1 (starless) suggests that the former has experienced a phase of rapid mass accretion, supported by the very long outflow it drives. The protostellar jet from IRAS 05399 might have influenced the nearby core SMM 1. In particular, the temperature map features are likely to be imprints of protostellar or shock heating, while external heating could be provided by the nearby high-mass star-forming region NGC 2024.

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MAMBO mapping of Spitzer c2d small clouds and cores

Cited by 648 publications

References 103 publications

Ammonia from cold high-mass clumps discovered in the inner Galactic disk by the ATLASGAL survey

Ammonia from cold high-mass clumps discovered in the inner Galactic disk by the ATLASGAL survey

Search for grain growth toward the center of L1544

SABOCA 350-μm and LABOCA 870-μm dust continuum imaging of IRAS 05399-0121: mapping the dust properties of a pre- and protostellar core system

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