Millimeter-wave survey of molecular clouds around the W5-East triggered star-forming region

Niwa, T.; Tachihara, Kengo; Itoh, Yoichi; Oasa, Yumiko; Sunada, Kazuyoshi; Sugitani, Koji; Mukai, T.

doi:10.1051/0004-6361/200811065

Cited by 19 publications

(25 citation statements)

References 41 publications

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“…The CS map of Carpenter et al (1993) shows that the east clump is by far the brightest. It is also the densest of all the CO clumps located in the periphery of W5, with a density of 2.6 × 10 4 cm −3 (Niwa et al 2009). It is the dense ionized layer bordering this clump that appears as the bright arc-shaped structure in the radio-continuum map and in Hα.…”

Section: B2 the Dense Condensation Enclosed By Brc14mentioning

confidence: 98%

“…2. High resolution observations of W5-E (HPBW = 15.6 ) have been obtained in the 13 CO (1−0) and C 18 O (1−0) lines by Niwa et al (2009). Eight clouds are identified (three of them are associated with the bright-rimmed clouds BRC12, BRC13, and BRC14), with masses in the range 460 M to 36 000 M 1 .…”

Section: Figmentioning

confidence: 99%

“…This cloud has been mapped in 12 CO(1−0) by Loren and Wootten (1978), Snell et al (1988), Carpenter et al (1990, Karr & Martin (2003). High resolution maps have been obtained by Niwa et al (2009;HPBW = 15.6 ) in 13 CO(1−0) and C 18 O(1−0). The condensation enclosed by BRC14 is their clump 7, the brightest one, with a peak column density in the range 5.8−9.4 × 10 22 cm −2 (depending on the transition), and a mass of 740 M .…”

Section: Appendix B: the Bright-rim Cloud Brc14 And Vicinitymentioning

confidence: 99%

“…Large-scale CO maps show the extent of this filament which goes from BRC14, through Sh 201, to eastern regions far away from Sh 201; its total east-west extent is ∼20 pc (Carpenter et al 2000;Karr & Martin 2003;Niwa et al 2009, their cloud 7). This filament has two condensations on each side of Sh 201 (clumps 8 and 9 in Niwa et al 2009). The CS map of Carpenter et al (1993) shows that the east clump is by far the brightest.…”

Section: B2 the Dense Condensation Enclosed By Brc14mentioning

confidence: 99%

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Interstellar matter and star formation in W5-E

Deharveng

Zavagno

Anderson

et al. 2012

A&A

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Aims. We identify the young stellar objects (YSOs) present in the vicinity of the W5-E H ii region, and study the influence of this H ii region on the star formation process in its surrounding molecular material.Methods. W5-E has been observed with the Herschel-PACS and -SPIRE photometers, as part of the HOBYS key program; maps have been obtained at 100 μm, 160 μm, 250 μm, 350 μm, and 500 μm. The dust temperature and column density have been obtained by fitting spectral energy distributions (SEDs). Point sources have been detected and measured using PSF photometry with DAOPHOT. Results. The dust temperature map shows a rather uniform temperature, in the range 17.5 K−20 K in the dense condensations or filaments, in the range 21 K−22 K in the photodissociation regions (PDRs), and in the range 24 K−31 K in the direction of the ionized regions. The values in the column density map are rather low, everywhere lower than 10 23 cm −2 , and of the order of a few 10 21 cm −2 in the PDRs. About 8000 M of neutral material surrounds the ionized region, which is low with respect to the volume of this H ii region; we suggest that the exciting stars of the W5-E, W5-W, Sh 201, A and B H ii regions formed along a dense filament or sheet rather than inside a more spherical cloud. Fifty point sources have been detected at 100 μm. Most of them are Class 0/I YSOs. The SEDs of their envelopes have been fitted using a modified blackbody model. These envelopes are cold, with a mean temperature of 15.7 ± 1.8 K.Their masses are in the range 1.3 M -47 M . Eleven of these point sources are candidate Class 0 YSOs. Twelve of these point sources are possibly at the origin of bipolar outflows detected in this region. None of the YSOs contain a massive central object, but a few may form a massive star as they have both a massive envelope and also a high envelope accretion rate. Most of the Class 0/I YSOs are observed in the direction of high column density material, for example in the direction of the massive condensations present at the waist of the bipolar Sh 201 H ii region or enclosed by the bright-rimmed cloud BRC14. The overdensity of Class 0/I YSOs on the borders of the H ii regions present in the field strongly suggests that triggered star formation is at work in this region but, due to insufficient resolution, the exact processes at the origin of the triggering are difficult to determine.

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Section: B2 the Dense Condensation Enclosed By Brc14mentioning

confidence: 98%

Section: Figmentioning

confidence: 99%

Section: Appendix B: the Bright-rim Cloud Brc14 And Vicinitymentioning

confidence: 99%

Section: B2 the Dense Condensation Enclosed By Brc14mentioning

confidence: 99%

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Interstellar matter and star formation in W5-E

Deharveng

Zavagno

Anderson

et al. 2012

A&A

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“…This mechanism may induce multiple cloud components with different velocities. However, our targets are not contained in the catalogs of galactic supernovae (Green 2009) and bubbles, which are detected in Spitzer/GLIMPSE survey (Churchwell et al 2006), by contrast the Cassiopeia A (e.g., Maeda et al 2009) or W3/W4/W5 regions (e.g., Allen et al 2005;Niwa et al 2009). There are no spatial correlations between the areas of large velocity dispersion and the outflow lobes (see the right panel of Figure 1 to 5).…”

Section: Clump-clump Collision As a Possible Triggering Of Cluster Fomentioning

confidence: 99%

A Mapping Survey of Dense Clumps Associated With Embedded Clusters. Ii. Can Clump-Clump Collisions Induce Stellar Clusters?

Higuchi

Kurono

Saito

et al. 2010

ApJ

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We report the H 13 CO + (J=1-0) survey observations toward embedded clusters obtained using the Nobeyama 45m telescope, which were performed to follow up our previous study in the C 18 O survey with a dense gas tracer. Our aim is to address the evolution of cluster-forming clumps. We observed the same 14 clusters in C 18 O, which are located at distances from 0.3 to 2.1 kpc with 27 ′′ resolution (corresponding to Jeans length for most of our targets) in H 13 CO + . We detected the 13 clumps in H 13 CO + line emission and obtained the physical parameters of the clumps with radii of 0.24-0.75 pc, masses of 100-1400 M ⊙ , and velocity widths in FWHM of 1.5-4.0 km s −1 . The mean density is ∼ 3.9 × 10 4 cm −3and the equivalent Jeans length is ∼ 0.13 pc at 20 K. We classified the H 13 CO + clumps into three types, Type A, Type B , and Type C according to the relative locations of the H 13 CO + clumps and the clusters (see our previous study). Our classification represents an evolutionary trend of cluster-forming clumps because dense clumps are expected to be converted into stellar constituents, or dispersed by stellar activities. We found a similar but clearer trend than our previous results for derived star formation efficiencies to increase from Type A to C in the H 13 CO + data, and for the dense gas regions within the clumps traced by H 13 CO + to be sensitive to the physical evolution of clump-cluster systems. In addition, we found that four out of 13 H 13 CO + clumps which we named "DVSOs" (Distinct 1 National Astronomical Observatory of Japan 2-21-1 Osawa, Mitaka, Tokyo, 181-8588, Japan 2 Nobeyama Radio Observatory, Nobeyama, Minamimaki, Minamisaku, Nagano 384-1305, Japan -2 -Velocity Structure Objects) have distinct velocity gradients at the central parts of them, i.e., at the location of the embedded clusters. Assuming that the velocity gradients represent the rigid-like rotation of the clumps, we calculated the virial parameter of the H 13 CO + clumps by taking into account the contribution of rotation, and found that the DVSOs tend to be gravitationally unbound. In order to explain the above physical properties for DVSOs in a consistent way, we propose a clump-clump collision model as a possible mechanism for triggering formation of clusters.

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Globules and pillars in Cygnus X

Djupvik

Comerón

Schneider

2017

A&A

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Globules and pillars, impressively revealed by the Spitzer and Herschel satellites, for example, are pervasive features found in regions of massive star formation. Studying their embedded stellar populations can provide an excellent laboratory to test theories of triggered star formation and the features that it may imprint on the stellar aggregates resulting from it. We studied the globule IRAS 20319+3958 in Cygnus X by means of visible and near-infrared imaging and spectroscopy, complemented with mid-infrared Spitzer/IRAC imaging, in order to obtain a census of its stellar content and the nature of its embedded sources. Our observations show that the globule contains an embedded aggregate of about 30 very young ( 1 Myr) stellar objects, for which we estimate a total mass of ∼90 M . The most massive members are three systems containing early B-type stars. Two of them most likely produced very compact H II regions, one of them being still highly embedded and coinciding with a peak seen in emission lines characterising the photon dominated region (PDR). Two of these three systems are resolved binaries, and one of those contains a visible Herbig Be star. An approximate derivation of the mass function of the members of the aggregate gives hints of a slope at high masses shallower than the classical Salpeter slope, and a peak of the mass distribution at a mass higher than that at which the widely adopted log-normal initial mass function peaks. The emission distribution of H 2 and Brγ, tracing the PDR and the ionised gas phase, respectively, suggests that molecular gas is distributed as a shell around the embedded aggregate, filled with centrally-condensed ionised gas. Both, the morphology and the low excitation of the H II region, indicate that the sources of ionisation are the B stars of the embedded aggregate, rather than the external UV field caused by the O stars of Cygnus OB2. The youth of the embedded cluster, combined with the isolation of the globule, suggests that star formation in the globule was triggered by the passage of the ionisation front.

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Millimeter-wave survey of molecular clouds around the W5-East triggered star-forming region

Cited by 19 publications

References 41 publications

Interstellar matter and star formation in W5-E

Interstellar matter and star formation in W5-E

A Mapping Survey of Dense Clumps Associated With Embedded Clusters. Ii. Can Clump-Clump Collisions Induce Stellar Clusters?

Globules and pillars in Cygnus X

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