The Nature of the Dense Core Population in the Pipe Nebula: Thermal Cores Under Pressure

Lada, Charles J.; Muench, August; Rathborne, Jill; Alves, J.; Lombardi, Marco

doi:10.1086/523837

Cited by 219 publications

(323 citation statements)

References 53 publications

(69 reference statements)

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“…André et al André et al 2010 andKönyves et al 2010). For comparison, the locations of the (sub)mm continuum prestellar cores identified by Motte et al (1998Motte et al ( , 2001 in ρ Oph and NGC2068/2071, respectively, are shown, along with the dust extinction cores of the Pipe nebula (Alves et al 2007, Lada et al 2008, and the correlation observed for diffuse CO clumps (shaded band -cf. Elmegreen & Falgarone 1996).…”

Section: First Results From Herschel On the Cmf-imf Connectionmentioning

confidence: 99%

“…This finding is reminiscent of the CMF results obtained with ground-based (sub)millimeter dust continuum observations, although most of the starless cores in the Pipe Nebula are gravitationally unbound objects confined by external IAUS 270. Prestellar core mass functions and link to the IMF 257 pressure (Lada et al 2008). Hence, a large fraction of them do not qualify as prestellar cores and may never evolve into stars.…”

Section: Prestellar Core Mass Functions From Ground-based Observationsmentioning

confidence: 99%

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Origin of the prestellar core mass function and link to the IMF – Herschel first results

André¹,

Könyves²,

Arzoumanian³

2010

Proc. IAU

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Abstract. We briefly review ground-based (sub)millimeter dust continuum observations of the prestellar core mass function (CMF) and its connection to the stellar initial mass function (IMF). We also summarize the first results obtained on this topic from the Herschel Gould Belt survey, one of the largest key projects with the Herschel Space Observatory. Our early findings with Herschel confirm the existence of a close relationship between the CMF and the IMF. Furthermore, they suggest a scenario according to which the formation of prestellar cores occurs in two main steps: 1) complex networks of long, thin filaments form first, probably as a result of interstellar MHD turbulence; 2) the densest filaments then fragment and develop prestellar cores via gravitational instability.

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Section: First Results From Herschel On the Cmf-imf Connectionmentioning

confidence: 99%

Section: Prestellar Core Mass Functions From Ground-based Observationsmentioning

confidence: 99%

Origin of the prestellar core mass function and link to the IMF – Herschel first results

André¹,

Könyves²,

Arzoumanian³

2010

Proc. IAU

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“…In an idealized case, a constant volume density trend is expected if IRDC cores are in pressure balance (cf. the Pipe Nebula, Lada et al 2008). However, there are several observational issues one must keep in mind.…”

Section: Irdc Small-scale Structurementioning

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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“…1.2. Second, a radius was calculated for the core from the mass-to-radius relation log 2R = 0.35 × log M + 0.65 that was derived for the cores of the Pipe nebula by Lada et al (2008). In the equation, R is given in arcminutes and M in solar masses.…”

Section: Simulated Extinction Mapsmentioning

confidence: 99%

“…The procedure is the same as used by ALL07, and it is outlined in their paper (see also Sect. 2.1 of Lada et al 2008). First, the extinction map was decomposed with a wavelet transformation at 4 scale.…”

Section: The Core Extractionmentioning

confidence: 99%

The fidelity of the core mass functions derived from dust column density data

Kainulainen

Lada

Rathborne

2009

A&A

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Aims. We examine the recoverability and completeness limits of the dense core mass functions (CMFs) derived for a molecular cloud using extinction data and a core identification scheme based on two-dimensional thresholding. We study how the selection of core extraction parameters affects the accuracy and completeness limit of the derived CMF and the core masses, and also how accurately the CMF can be derived in varying core crowding conditions. Methods. We performed simulations where a population of artificial cores was embedded in the variable background extinction field of the Pipe nebula. We extracted the cores from the simulated extinction maps, constructed the CMFs, and compared them to the input CMFs. The simulations were repeated using a variety of extraction parameters and several core populations with differing input mass functions and differing degrees of crowding.Results. The fidelity of the observed CMF depends on the parameters selected for the core extraction algorithm for our background. More importantly, it depends on how crowded the core population is. We find that the observed CMF recovers the true CMF reliably when the mean separation of cores is larger than the mean diameter of the cores ( f > 1). If this condition holds, the derived CMF for the Pipe nebula background is accurate and complete above M > ∼ 0.8 . . . 1.5 M , depending on the parameters used for the core extraction. In the simulations, the best fidelity was achieved with the detection threshold of 1 or 2 times the rms-noise of the extinction data, and with the contour level spacings of 3 times the rms-noise. Choosing a higher threshold and wider level spacings increases the limiting mass. The simulations also show that, when f > ∼ 1.5, the masses of individual cores are recovered with a typical uncertainty of 25 . . . 30%. When f ≈ 1, the uncertainty is ∼60%. In very crowded cases where f < 1 the core identification algorithm is unable to recover the masses of the cores adequately, and the derived CMF is unlikely to represent the underlying CMF. For the cores of the Pipe nebula f ≈ 2.0 thereby justifying the use of the method in that region.

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The Nature of the Dense Core Population in the Pipe Nebula: Thermal Cores Under Pressure

Cited by 219 publications

References 53 publications

Origin of the prestellar core mass function and link to the IMF – Herschel first results

Origin of the prestellar core mass function and link to the IMF – Herschel first results

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

The fidelity of the core mass functions derived from dust column density data

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