The formation of active protoclusters in the Aquila rift: a millimeter continuum view

Maury, A.; André, P.; Men’shchikov, A.; Könyves, V.; Bontemps, Sylvain

doi:10.1051/0004-6361/201117132

Cited by 129 publications

(266 citation statements)

References 69 publications

(136 reference statements)

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“…André et al 2010). Core formation is particularly well documented in the case of the B211/B213 filament in Taurus (Schmalzl et al 2010;Onishi et al 2002) or the Serpens South filament in the Aquila Rift (Gutermuth et al 2008;Maury et al 2011).…”

Section: An Evolutionary Scenario For Interstellar Filaments?mentioning

confidence: 98%

Formation and evolution of interstellar filaments

Arzoumanian

André

Peretto

et al. 2013

A&A

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We investigate the gas velocity dispersions of a sample of filaments recently detected as part of the Herschel Gould Belt Survey in the IC 5146, Aquila, and Polaris interstellar clouds. To measure these velocity dispersions, we use 13 CO, C 18 O, and N 2 H + line observations obtained with the IRAM 30 m telescope. Correlating our velocity dispersion measurements with the filament column densities derived from Herschel data, we show that interstellar filaments can be divided into two regimes: thermally subcritical filaments, which have transonic velocity dispersions (c s < ∼ σ tot < 2 c s ) independent of column density and are gravitationally unbound; and thermally supercritical filaments, which have higher velocity dispersions scaling roughly as the square root of column density (σ tot ∝ Σ 0 0.5 ) and which are self-gravitating. The higher velocity dispersions of supercritical filaments may not directly arise from supersonic interstellar turbulence but may be driven by gravitational contraction/accretion. Based on our observational results, we propose an evolutionary scenario whereby supercritical filaments undergo gravitational contraction and increase in mass per unit length through accretion of background material, while remaining in rough virial balance. We further suggest that this accretion process allows supercritical filaments to keep their approximately constant inner widths (∼0.1 pc) while contracting.

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Section: An Evolutionary Scenario For Interstellar Filaments?mentioning

confidence: 98%

Formation and evolution of interstellar filaments

Arzoumanian

André

Peretto

et al. 2013

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“…This extinction-defined area (see Bontemps et al 2010), rich in gas but initially thought to be almost devoid of star formation (Prato et al 2008), is now known to harbor two cluster-forming clumps (Maury et al 2011): Serpens South, a young protostellar cluster showing very active recent star formation and embedded in a dense filamentary cloud (Gutermuth et al 2008;Bontemps et al 2010;Nakamura et al 2011;Teixeira et al 2012;Friesen et al 2013;Kirk et al 2013a;Tanaka et al 2013), and W40 a young star cluster associated with the eponymous HII region, also known as Sharpless 2-64 (Smith et al 1985;Vallee 1987;Kuhn et al 2010;Pirogov et al 2013).…”

Section: The Aquila Rift Regionmentioning

confidence: 99%

“…Whether or not the southern part of the Aquila highextinction region and the Serpens Main cloud are at the same distance is still a matter of debate Maury et al 2011;Loinard 2013). Based on stellar photometry, Straižys et al (2003) concluded that the front edge of the Aquila molecular cloud was at 255 ± 55 pc.…”

Section: The Aquila Rift Regionmentioning

confidence: 99%

A census of dense cores in the Aquila cloud complex: SPIRE/PACS observations from theHerschelGould Belt survey

Könyves

André

Men’shchikov

et al. 2015

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We present and discuss the results of the Herschel Gould Belt survey (HGBS) observations in an ∼11 deg 2 area of the Aquila molecular cloud complex at d ∼ 260 pc, imaged with the SPIRE and PACS photometric cameras in parallel mode from 70 μm to 500 μm. Using the multi-scale, multi-wavelength source extraction algorithm getsources, we identify a complete sample of starless dense cores and embedded (Class 0-I) protostars in this region, and analyze their global properties and spatial distributions. We find a total of 651 starless cores, ∼60% ± 10% of which are gravitationally bound prestellar cores, and they will likely form stars in the future. We also detect 58 protostellar cores. The core mass function (CMF) derived for the large population of prestellar cores is very similar in shape to the stellar initial mass function (IMF), confirming earlier findings on a much stronger statistical basis and supporting the view that there is a close physical link between the stellar IMF and the prestellar CMF. The global shift in mass scale observed between the CMF and the IMF is consistent with a typical star formation efficiency of ∼40% at the level of an individual core. By comparing the numbers of starless cores in various density bins to the number of young stellar objects (YSOs), we estimate that the lifetime of prestellar cores is ∼1 Myr, which is typically ∼4 times longer than the core free-fall time, and that it decreases with average core density. We find a strong correlation between the spatial distribution of prestellar cores and the densest filaments observed in the Aquila complex. About 90% of the Herschel-identified prestellar cores are located above a background column density corresponding to A V ∼ 7, and ∼75% of them lie within filamentary structures with supercritical masses per unit length > ∼ 16 M /pc. These findings support a picture wherein the cores making up the peak of the CMF (and probably responsible for the base of the IMF) result primarily from the gravitational fragmentation of marginally supercritical filaments. Given that filaments appear to dominate the mass budget of dense gas at A V > 7, our findings also suggest that the physics of prestellar core formation within filaments is responsible for a characteristic "efficiency" SFR/M dense ∼ 5 +2 −2 × 10 −8 yr −1 for the star formation process in dense gas.

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“…1.1 for FHSC lifetimes) or a Class 0 protostar. The prestellar phase lifetime is estimated to be ∼0.5 Myr (Evans et al 2009), and Class 0 objects have estimated lifetimes ranging from ∼4−9 × 10 4 yr (Maury et al 2011) to ∼1.6 × 10 5 yr (Evans et al 2009). Belloche et al (2002) similarly performed radiative transfer modelling of their molecular transitions towards the young Class 0 IRAM 04191 protostar using the MAPYSO code.…”

Section: Infall In Cha-mms1 and In Other Observed Coresmentioning

confidence: 99%

The dynamical state of the first hydrostatic core candidate Chamaeleon-MMS1

Tsitali¹,

Беллоче²,

Commerçon³

et al. 2013

A&A

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Context. First hydrostatic cores represent a theoretically predicted intermediate evolutionary link between the prestellar and protostellar phases. Studying the observational characteristics of first core candidates is therefore vital for probing and understanding the earliest phases of star formation. Aims. We aim to determine the dynamical state of the first hydrostatic core candidate Chamaeleon-MMS1 (Cha-MMS1). Methods. We observed Cha-MMS1 in various molecular transitions with the APEX and Mopra telescopes. Continuum data retrieved from the Spitzer Heritage Archive were used to estimate the internal luminosity of the source. The molecular emission was modelled with a radiative transfer code to derive constraints on the kinematics of the envelope, which were then compared to the predictions of magneto-hydrodynamic simulations. Results. We derive an internal luminosity of 0.08 L −0.18 L for Cha-MMS1. An average velocity gradient of 3.1 ± 0.1 km s −1 pc −1 over ∼0.08 pc is found perpendicular to the filament in which Cha-MMS1 is embedded. The gradient is flatter in the outer parts and, surprisingly, also at the innermost ∼2000 AU to 4000 AU. The former features are consistent with solid-body rotation beyond 4000 AU and slower, differential rotation beyond 8000 AU, but the origin of the flatter gradient in the innermost parts is unclear. The classical infall signature is detected in HCO + 3−2 and CS 2−1. The radiative transfer modelling indicates a uniform infall velocity in the outer parts of the envelope. In the inner parts (at most 9000 AU), an infall velocity field scaling with r −0.5 is consistent with the data, but the shape of the profile is less well constrained and the velocity could also decrease toward the centre. The infall velocities are subsonic to transonic, 0.1 km s −1 −0.2 km s −1 at r ≥ 3300 AU, and subsonic to supersonic, 0.04 km s −1 −0.6 km s −1 at r ≤ 3300 AU. Both the internal luminosity of Cha-MMS1 and the infall velocity field in its envelope are consistent with predictions of MHD simulations for the first core phase. There is no evidence of any fast, large-scale outflow stemming from Cha-MMS1, but excess emission from the high-density tracers CS 5−4, CO 6−5, and CO 7−6 suggests the presence of higher velocity material at the inner core. Conclusions. Its internal luminosity excludes Cha-MMS1 being a prestellar core. The kinematical properties of its envelope are consistent with Cha-MMS1 being a first hydrostatic core candidate or a very young Class 0 protostar.

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The formation of active protoclusters in the Aquila rift: a millimeter continuum view

Cited by 129 publications

References 69 publications

Formation and evolution of interstellar filaments

Formation and evolution of interstellar filaments

A census of dense cores in the Aquila cloud complex: SPIRE/PACS observations from theHerschelGould Belt survey

The dynamical state of the first hydrostatic core candidate Chamaeleon-MMS1

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