DETECTION OF STRUCTURE IN INFRARED-DARK CLOUDS WITH<i>SPITZER</i>: CHARACTERIZING STAR FORMATION IN THE MOLECULAR RING

Ragan, S. E.; Bergin, Edwin A.; Gutermuth, Robert

doi:10.1088/0004-637x/698/1/324

Cited by 63 publications

(98 citation statements)

References 71 publications

(166 reference statements)

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“…Marshall et al (2009), Ragan et al (2009), and Peretto & Fuller (2010 have studied the mass distribution of IRDCs obtained from extinction maps. In particular, Ragan et al (2009) computed the mass distribution of cores using Clumpfind in 11 IRDCs and fitted broken power laws of α low = −0.52 ± 0.04 and α high = −1.76 ± 0.05 for masses lower than 40 M and for masses greater than 40 M , (Simon et al 2006b), Pe10 (Peretto & Fuller 2010), Ma09 (Marshall et al 2009), Mi12 (Miettinen 2012), Ra09 (Ragan et al 2009), Re06a (Reid & Wilson 2006a), Mo04 (Mookerjea et al 2004), Mu07 (Muñoz et al 2007). respectively. Using Gaussclumps, the slope becomes shallower: α high = −1.15 ± 0.04 and α low = −0.64 ± 0.07 for the same break-point mass.…”

Section: Mass Spectramentioning

confidence: 99%

“…Therefore, IRDCs are good candidates for studying the mass distribution of their clumps/cores. Different studies of the mass distributions of IRDCs based on either extinction or continuum maps and different assumptions, e.g., source extraction, mass estimation, etc., find a range of indices from α ∼ −1.7 to −2.1 (e.g., Rathborne et al 2006;Ragan et al 2009;Peretto & Fuller 2010;Miettinen 2012). …”

Section: Introductionmentioning

confidence: 99%

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The mass distribution of clumps within infrared dark clouds. A Large APEX Bolometer Camera study

Gómez

Wyrowski

Schüller

et al. 2014

A&A

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Aims. We present an analysis of the dust continuum emission at 870 μm in order to investigate the mass distribution of clumps within infrared dark clouds (IRDCs). Methods. We map six IRDCs with the Large APEX BOlometer CAmera (LABOCA) at APEX, reaching an rms noise level of σ rms = 28 -44 mJy beam −1 . The dust continuum emission coming from these IRDCs was decomposed by using two automated algorithms, Gaussclumps and Clumpfind. Moreover, we carried out single-pointing observations of the N 2 H + (3-2) line toward selected positions to obtain kinematic information. Results. The mapped IRDCs are located in the range of kinematic distances of 2.7-3.2 kpc. We identify 510 and 352 sources with Gaussclumps and Clumpfind, respectively, and estimate masses and other physical properties assuming a uniform dust temperature. The mass ranges are 6-2692 M (Gaussclumps) and 7-4254 M (Clumpfind), and the ranges in effective radius are ∼0.10-0.74 pc (Gaussclumps) and 0.16-0.99 pc (Clumpfind). The mass distribution, independent of the decomposition method used, is fitted by a power law, dN/dM ∝ M α , with an index (α) of −1.60 ± 0.06, consistent with the CO mass distribution and other high-mass star-forming regions.

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Section: Mass Spectramentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The mass distribution of clumps within infrared dark clouds. A Large APEX Bolometer Camera study

Gómez

Wyrowski

Schüller

et al. 2014

A&A

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“…Rathborne et al 2006;Ragan et al 2009;Battersby et al 2010). They are located throughout the Galactic plane, concentrated within the spiral arms (Jackson et al 2008).…”

Section: Background and Motivationmentioning

confidence: 99%

APEX/SABOCA observations of small-scale structure of infrared-dark clouds

Ragan

Henning

Beuther

2013

A&A

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Infrared-dark clouds (IRDCs) harbor the early phases of cluster and high-mass star formation and are comprised of cold (∼20 K), dense (n > 10 4 cm −3 ) gas. The spectral energy distribution (SED) of IRDCs is dominated by the far-infrared and millimeter wavelength regime, and our initial Herschel study examined IRDCs at the peak of the SED with high angular resolution. Here we present a follow-up study using the SABOCA instrument on APEX which delivers 7.8 angular resolution at 350 µm, matching the resolution we achieved with Herschel/PACS, and allowing us to characterize substructure on ∼0.1 pc scales. Our sample of 11 nearby IRDCs are a mix of filamentary and clumpy morphologies, and the filamentary clouds show significant hierarchical structure, while the clumpy IRDCs exhibit little hierarchical structure. All IRDCs, regardless of morphology, have about 14% of their total mass in small scale core-like structures which roughly follow a trend of constant volume density over all size scales. Out of the 89 protostellar cores we identified in this sample with Herschel, we recover 40 of the brightest and re-fit their SEDs and find their properties agree fairly well with our previous estimates ( T ∼ 19 K). We detect a new population of "cold cores" which have no 70 µm counterpart, but are 100 and 160 µm-bright, with colder temperatures ( T ∼ 16 K). This latter population, along with SABOCA-only detections, are predominantly low-mass objects, but their evolutionary diagnostics are consistent with the earliest starless or prestellar phase of cores in IRDCs.Key words. catalogs -stars: formation -ISM: structure -submillimeter: ISM Background and motivationDespite the importance of high-mass stars to the energy budget of galaxies, their formation remains a major open question in astronomy (Zinnecker & Yorke 2007). A major hindrance to progress is the inherent difficulty in obtaining well-defined initial conditions observationally. Because high-mass stars are rare, they are on average at large distances, thus angular resolution is of paramount importance. With the advent of Spitzer Space Telescope and Herschel Space Observatory (Pilbratt et al. 2010), coupled with extensive ground-based survey efforts, we now can approach this observational task statistically.Ever since their discovery in absorption in mid-infrared Galactic plane surveys, ISO data (Perault et al. 1996) and MSX observations (Egan et al. 1998), infrared-dark clouds (IRDCs) have been subject to intense study because they are the cold (T < 20 K), dense (n > 10 4 cm −3 ) environments believed to be required for the formation of high-mass stars and clusters (cf. Rathborne et al. 2006;Ragan et al. 2009;Battersby et al. 2010). They are located throughout the Galactic plane, concentrated within the spiral arms (Jackson et al. 2008). The formation of IRDCs, their kinematic structure and population of Based on observations carried out with the Atacama Pathfinder Experiment (APEX). APEX is a collaboration between Max Planck Institut für Radioastronomie (MPIf...

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“…Since then, follow-up Full Table 1 is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/590/A72 observations have shown that these sources are cold, dense molecular clouds and potential mass reservoirs for future generations of stars (e.g. Teyssier et al 2002;Simon et al 2006;Rathborne et al 2006;Ragan et al 2009). Their darkness in the mid-infrared domain ensures that these sources represent early stages in dense cloud evolution and, as such, IRDCs might contain the initial conditions of star formation.…”

Section: Introductionmentioning

confidence: 99%

The initial conditions for stellar protocluster formation

Peretto

Lenfestey

Fuller

et al. 2016

A&A

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Context. Galactic plane surveys of pristine molecular clouds are key for establishing a Galactic-scale view of star formation. For this reason, an unbiased sample of infrared dark clouds in the 10 • < |l| < 65 • , |b| < 1 • region of the Galactic plane was built using Spitzer 8 µm extinction. However, intrinsic fluctuations in the mid-infrared background can be misinterpreted as foreground clouds. Aims. The main goal of this study is to disentangle real clouds in the Spitzer Dark Cloud (SDC) catalogue from artefacts due to fluctuations in the mid-infrared background. Methods. We constructed H 2 column density maps at ∼18 resolution using the 160 µm and 250 µm data from the Herschel Galactic plane survey Hi-GAL. We also developed an automated detection scheme that confirms the existence of a SDC through its association with a peak on these Herschel column density maps. Detection simulations, along with visual inspection of a small sub-sample of SDCs, have been performed to get more insight into the limitations of our automated identification scheme. Results. Our analysis shows that 76(±19)% of the catalogued SDCs are real. This fraction drops to 55(±12)% for clouds with angular diameters larger than ∼1 arcmin. The contamination of the PF09 catalogue by large spurious sources reflects the large uncertainties associated to the construction of the 8 µm background emission, a key stage in identiying SDCs. A comparison of the Herschel confirmed SDC sample with the BGPS and ATLASGAL samples shows that SDCs probe a unique range of cloud properties, reaching down to more compact and lower column density clouds than any of these two (sub-)millimetre Galactic plane surveys. Conclusions. Even though about half of the large SDCs are spurious sources, the vast majority of the catalogued SDCs do have a Herschel counterpart. The Herschel-confirmed sample of SDCs offers a unique opportunity to study the earliest stages of both lowand high-mass star formation across the Galaxy.

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DETECTION OF STRUCTURE IN INFRARED-DARK CLOUDS WITHSPITZER: CHARACTERIZING STAR FORMATION IN THE MOLECULAR RING

Cited by 63 publications

References 71 publications

The mass distribution of clumps within infrared dark clouds. A Large APEX Bolometer Camera study

The mass distribution of clumps within infrared dark clouds. A Large APEX Bolometer Camera study

APEX/SABOCA observations of small-scale structure of infrared-dark clouds

The initial conditions for stellar protocluster formation

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