Star Formation in the Molecular Cloud Associated With the Monkey Head Nebula: Sequential or Spontaneous?

Chibueze, James O.; Imura, Kenji; Omodaká, Toshihiro; Handa, Toshihiro; Nagayama, Tomonori; Fujisawa, Kenta; Sunada, Kazuyoshi; Nakano, Makoto; Kamezaki, Tatsuya; Yamaguchi, Yoshiyuki; Sekido, Mamoru

doi:10.1088/0004-637x/762/1/17

Cited by 11 publications

(12 citation statements)

References 35 publications

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“…superposed on the optical Digitized Sky Survey (DSS) image (red scale). For the S252 H ii region, the radio continuum map at 8.4 GHz (Chibueze et al 2013, see their Figure 5) which originates from the ionized gas in the H ii region shows similar morphology with the DSS image. As seen in Figure 1(a), the 12 CO emission is enhanced along the boundaries of the two H ii regions (S247 and S252), suggesting an interaction between the molecular and ionized gas.…”

Section: Global Distributions Of Young Stellar Objects and Molecular mentioning

confidence: 57%

“…Note that most of the clusters are located at the interfaces of the two velocity components. We therefore suggest that cloud-cloud collision on a large scale induced the formation of most of the clusters in the S247/S252 regions, although we cannot rule out other possibilities such as the compression of the clumps by the expansion of the H ii regions or spontaneous star formation due to the self-gravity of the clumps suggested by the other authors as mentioned above (e.g., Carpenter et al 1995a;Chibueze et al 2013). Such a collision of GMCs triggering active star formation (including cluster formation) has already been evidenced in the Sgr B2 region (Hasegawa et al 1994;Sato et al 2000) and more recently in the Trifid Nebula (Torii et al 2011), indicating that collisions of GMCs should play a key role in cluster formation.…”

Section: Global Distributions Of Young Stellar Objects and Molecular mentioning

confidence: 71%

“…Carpenter et al (1995aCarpenter et al ( , 1995b argued that, throughout the Gemini OB1 cloud complex, star formation has been initiated by the compression of molecular clouds through the effects of stellar winds and expansion of the H ii regions. However, Chibueze et al (2013) who mapped the molecular cloud around the S252 region with the NH 3 line and continuum emission suggested that the molecular cloud in the S252 region was formed spontaneously by its self-gravity, not by the expansion of the S252 H ii region. In addition to these hypotheses, we suggest that star formation in this region was triggered by a large-scale cloud-cloud collision, which is inferred from the global velocity distribution of the CO emission (see below).…”

Section: Global Distributions Of Young Stellar Objects and Molecular mentioning

confidence: 99%

“…One of them, which we call Clump 7a, is associated with the cluster AFGL5179 as well as the IRAS source 06055+2039, and the other, Clump 7b, is not associated with any clusters. Chibueze et al (2013) mapped this clump in NH 3 lines to derive a temperature map of dense gas, and they found that warmer gas is confined to a small region around the UC H ii region. They also suggested that Clump 7 is less affected by the expansion of the S252 H ii region.…”

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confidence: 99%

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Molecular Clumps and Infrared Clusters in the S247, S252, and Bfs52 Regions

Shimoikura

Dobashi

Saito

et al. 2013

ApJ

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We present results of the observations carried out toward the S247, S252, and BFS52 H ii regions with various molecular lines using the 1.85 m radio telescope and the 45 m telescope at Nobeyama Radio Observatory. There are at least 11 young infrared clusters (IR clusters) within the observed region. We found that there are two velocity components in 12 CO (J = 2-1), and also that their spatial distributions show an anti-correlation. The IR clusters are located at their interfaces, suggesting that two distinct clouds with different velocities are colliding with each other, which may have induced the cluster formation. Based on 13 CO (J = 1-0) and C 18 O (J = 1-0) observations, we identified 16 clumps in and around the three H ii regions. Eleven of the clumps are associated with the IR clusters and the other five clumps are not associated with any known young stellar objects. We investigated variations in the velocity dispersions of the 16 clumps as a function of the distance from the center of the clusters or the clumps. Clumps with clusters tend to have velocity dispersions that increase with distance from the cluster center, while clumps without clusters show a flat velocity dispersion over the clump extents. A 12 CO outflow has been found in some of the clumps with IR clusters but not in the other clumps, supporting a strong relation of these clumps to the broader velocity dispersion region. We also estimated a mean star formation efficiency of ∼30% for the clumps with IR clusters in the three H ii regions.

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Section: Global Distributions Of Young Stellar Objects and Molecular mentioning

confidence: 57%

Section: Global Distributions Of Young Stellar Objects and Molecular mentioning

confidence: 71%

Section: Global Distributions Of Young Stellar Objects and Molecular mentioning

confidence: 99%

mentioning

confidence: 99%

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Molecular Clumps and Infrared Clusters in the S247, S252, and Bfs52 Regions

Shimoikura

Dobashi

Saito

et al. 2013

ApJ

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“…As the mass of the cloud estimated by them is consistent with ours, the star formation Hindson et al 2010;Urquhart et al 2011). In the case of Gem OB1 cloud, the dense cloud in contact with an expanding HII region showed no obvious observable interaction between them (Chibueze et al 2013). On the other hand, the observed large velocity widths found in the northern and southern surroundings of HII region G 134.2+0.8 (see figure 4) is evident, and these feature suggests G 134.2+0.8 is interacting with the dense molecular gas of AFGL 333-Ridge.…”

Section: Star Formation Activity In the Regionmentioning

confidence: 99%

Interaction between the H ii region and AFGL 333-Ridge: Implications for the star formation scenario

Nakano

Takashi

Chibueze

et al. 2017

Publications of the Astronomical Society of Japan

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We investigated the star formation activities in the AFGL 333 region, which is in the vicinity of the W4 expanding bubble, by conducting NH 3 (1,1), (2,2), and (3,3) mapping observations with the 45 m Nobeyama Radio Telescope at an angular resolution of 75 ′′ . The morphology of the NH 3 (1,1) map shows a bow-shape structure with the size of 2.0 × 0.6 pc as seen in the dust continuum. At the interface between the W4 bubble and the dense NH 3 cloud, the compact HII region G 134.2+0.8, associated with IRAS 02245+6115, is located. Interestingly, just north and south of G 134.2+0.8 we found NH 3 emission exhibiting large velocity widths of ∼ 2.8 km s −1 , compared to 1.8 km s −1 at the other positions. As the possibility of mechanical energy injection through the activity of YSO(s) is low, we considered the origin of the large turbulent gas motion as indication of interaction between the compact HII region and the periphery of the dense molecular cloud. We also found expanding motion of the CO emission associated with G 134.2+0.8. The overall structure of the AFGL 333-Ridge might have been formed by the expanding bubble of W4. However, the small velocity widths observed west of IRAS 02245+6115, around the center of the dense molecular cloud, suggest that interaction with the compact HII region is limited. Therefore the YSOs (dominantly Class 0/I) in the core of the AFGL 333-Ridge dense molecular cloud most likely formed in quiescent mode. As has been previously suggested for the large scale star formation in the W3 giant molecular cloud, our results show an apparent coexistence of induced and quiescent star formation in this region. It appears that star formation in the AFGL 333 region has proceeded without significant external triggers, but accompanying stellar feedback environment.

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Colliding Filaments and a Massive Dense Core in the Cygnus Ob 7 Molecular Cloud

Dobashi¹,

Matsumoto

Shimoikura³

et al. 2014

ApJ

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We report results of molecular line observations carried out toward a massive dense core in the Cyg OB 7 molecular cloud. The core has an extraordinarily large mass (∼ 1.1 × 10 4 M ⊙ ) and size (∼ 2 × 5 pc 2 ), but there is no massive young star forming therein. We observed this core in various molecular lines such as C 18 O(J = 1 − 0) using the 45m telescope at Nobeyama Radio Observatory. We find that the core has an elongated morphology consisting of several filaments and core-like structures. The filaments are massive (10 2 − 10 3 M ⊙ ), and they are apparently colliding against each other. Some candidates of YSOs are distributed around their intersection, suggesting that the collisions of the filaments may have influenced on their formation. To understand the formation and evolution of such colliding filaments, we performed numerical simulations using the adaptive mesh refinement (AMR) technique adopting the observed core parameters (e.g., the mass and size) as the initial conditions. Results indicate that the filaments are formed as seen in other earlier simulations for small cores in literature, but we could not reproduce the collisions of the filaments simply by assuming the large initial mass and size. We find that the collisions of the filaments occur only when there is a large velocity gradient in the initial core in a sense to compress it. We suggest that the observed core was actually compressed by an external effect, e.g., shocks of nearby supernova remnants including HB21 which has been suggested to be interacting with the Cyg OB 7 molecular cloud.

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Star Formation in the Molecular Cloud Associated With the Monkey Head Nebula: Sequential or Spontaneous?

Cited by 11 publications

References 35 publications

Molecular Clumps and Infrared Clusters in the S247, S252, and Bfs52 Regions

Molecular Clumps and Infrared Clusters in the S247, S252, and Bfs52 Regions

Interaction between the H ii region and AFGL 333-Ridge: Implications for the star formation scenario

Colliding Filaments and a Massive Dense Core in the Cygnus Ob 7 Molecular Cloud

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