Hub-filament System in IRAS 05480+2545: Young Stellar Cluster and 6.7 GHz Methanol Maser

Dewangan, L. K.; Ojha, D. K.; Baug, Tapas

doi:10.3847/1538-4357/aa79a5

Cited by 25 publications

(16 citation statements)

References 53 publications

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“…Such filaments should be similar to the filaments in Taurus (Palmeirim et al 2013) and are often fertile (Hacar et al 2018), with ongoing low-mass star formation. This is because large populations of young low-mass stars have been found around high-mass protostars (Kumar et al 2006) and around HFSs (Dewangan et al 2017;Baug et al 2018).…”

Section: Stage I: Initial Conditionsmentioning

confidence: 99%

Unifying low- and high-mass star formation through density-amplified hubs of filaments

Kumar¹,

Palmeirim²,

Arzoumanian

et al. 2020

A&A

106

164

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Context. Star formation takes place in giant molecular clouds, resulting in mass-segregated young stellar clusters composed of Sun-like stars, brown dwarfs, and massive O-type(50–100 M⊙) stars. Aims. We aim to identify candidate hub-filament systems (HFSs) in the Milky Way and examine their role in the formation of the highest mass stars and star clusters. Methods. The Herschel survey HiGAL has catalogued about 105 clumps. Of these, approximately 35 000 targets are detected at the 3σ level in a minimum of four bands. Using the DisPerSE algorithm we detect filamentary skeletons on 10′ × 10′ cut-outs of the SPIRE 250 μm images (18′′ beam width) of the targets. Any filament with a total length of at least 55′′ (3 × 18′′) and at least 18′′ inside the clump was considered to form a junction at the clump. A hub is defined as a junction of three or more filaments. Column density maps were masked by the filament skeletons and averaged for HFS and non-HFS samples to compute the radial profile along the filaments into the clumps. Results. Approximately 3700 (11%) are candidate HFSs, of which about 2150 (60%) are pre-stellar and 1400 (40%) are proto-stellar. The filaments constituting the HFSs have a mean length of ~10–20 pc, a mass of ~5 × 104 M⊙, and line masses (M∕L) of ~2 × 103 M⊙ pc−1. All clumps with L > 104 L⊙ and L > 105 L⊙ at distances within 2 and 5 kpc respectively are located in the hubs of HFSs. The column densities of hubs are found to be enhanced by a factor of approximately two (pre-stellar sources) up to about ten (proto-stellar sources). Conclusions. All high-mass stars preferentially form in the density-enhanced hubs of HFSs. This amplification can drive the observed longitudinal flows along filaments providing further mass accretion. Radiation pressure and feedback can escape into the inter-filamentary voids. We propose a “filaments to clusters” unified paradigm for star formation, with the following salient features: (a) low-intermediate-mass stars form slowly (106 yr) in the filaments and massive stars form quickly (105 yr) in the hub, (b) the initial mass function is the sum of stars continuously created in the HFS with all massive stars formed in the hub, (c) feedback dissipation and mass segregation arise naturally due to HFS properties, and explain the (d) age spreads within bound clusters and the formation of isolated OB associations.

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Section: Stage I: Initial Conditionsmentioning

confidence: 99%

Unifying low- and high-mass star formation through density-amplified hubs of filaments

Kumar¹,

Palmeirim²,

Arzoumanian

et al. 2020

A&A

106

164

View full text Add to dashboard Cite

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“…Here, the moment-0 map of 13 CO is processed through an edge detection algorithm (i.e. Difference of Gaussian (DoG); see Gonzalez & Woods 2011;Assirati et al 2014;Dewangan et al 2017b). It enables us to visually probe five filaments (i.e., fk, fl, fm, fn, and fo) as seen in the Herschel column density map (see Figure 3d).…”

Section: Herschel Temperature and Column Density Mapsmentioning

confidence: 99%

New Insights into the H ii Region G18.88–0.49: Hub–Filament System and Accreting Filaments

Dewangan

Ojha

Sharma

et al. 2020

ApJ

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We present an analysis of multi-wavelength observations of an area of 0 • .27 × 0 • .27 around the Galactic H ii region G18.88−0.49, which is powered by an O-type star (age ∼10 5 years). The Herschel column density map reveals a shell-like feature of extension ∼12 pc × 7 pc and mass ∼2.9 ×10 4 M around the H ii region; its existence is further confirmed by the distribution of molecular ( 12 CO, 13 CO, C 18 O, and NH 3 ) gas at [60, 70] km s −1 . Four subregions are studied toward this shell-like feature, and show a mass range of ∼0.8-10.5 ×10 3 M . These subregions associated with dense gas are dominated by non-thermal pressure and supersonic non-thermal motions. The shell-like feature is associated with the H ii region, Class I protostars, and a massive protostar candidate, illustrating the ongoing early phases of star formation (including massive stars). The massive protostar is found toward the position of the 6.7 GHz methanol maser, and is associated with outflow activity. Five parsec-scale filaments are identified in the column density and molecular maps, and appear to be radially directed to the dense parts of the shell-like feature. This configuration is referred to as a "hub-filament" system. Significant velocity gradients (0.8-1.8 km s −1 pc −1 ) are observed along each filament, suggesting that the molecular gas flows towards the central hub along the filaments. Overall, our observational findings favor a global non-isotropic collapse scenario as discussed in Motte et al. (2018), which can explain the observed morphology and star formation in and around G18.88−0.49.

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“…Ultimately the global non-isotropic collapse scenario suggests that an infrared-bright massive protostar forms via the inflow from larger scales, and produces an H ii region (in a time of few 10 5 -10 6 yr) through its the stellar UV radiation. Some known sites hosting a hub-filament system are Ophiuchus (Myers 2009), Taurus (Myers 2009), Rosette (Schneider et al 2012), IRDC G14.225−0.506 (Busquet et al 2013), SDC335.579−0.292 (Peretto et al 2013), Sh 2-138 (Baug et al 2015), W42 (Dewangan et al 2015), IRAS 05480+2545 (Dewangan et al 2017b), Sh 2-53 (Baug et al 2018), and Monoceros R2 (Treviño-Morales et al 2019), and G18.88−0.49 (Dewangan et al 2020). More details of the global non-isotropic collapse scenario can be found in Tigé et al (2017); Motte et al (2018) (see also Treviño-Morales et al 2019;Dewangan et al 2020).…”

Section: Discussionmentioning

confidence: 99%

“…In order to further explore the embedded filaments, we processed the Herschel 160 µm image through an edge detection algorithm (i.e. Difference of Gaussian (DoG); see Gonzalez & Woods 2011;Assirati et al 2014;Dewangan et al 2017bDewangan et al , 2020. In Figure 2b, we display a two colorcomposite map made using the Herschel 160 µm image and the DoG processed 160 µm image.…”

Section: New Candidate Hub-filament System In G254nwmentioning

confidence: 99%

Unraveling the inner substructure of new candidate hub-filament system in the HII region G25.4NW

Dewangan

2021

Preprint

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We present multi-scale and multi-wavelength data of the Galactic H ii region G25.4-0.14 (hereafter G25.4NW, distance ∼5.7 kpc). The SHARC-II 350 µm continuum map displays a hub-filament configuration containing five parsec scale filaments and a central compact hub. Through the 5 GHz radio continuum map, four ionized clumps (i.e., Ia-Id) are identified toward the central hub, and are powered by massive OBstars. The Herschel temperature map depicts the warm dust emission (i.e., T d ∼23-39 K) toward the hub. High resolution Atacama Large Millimeter/submillimeter Array (ALMA) 1.3 mm continuum map (resolution ∼0. 82 × 0. 58) reveals three cores (c1-c3; mass ∼80-130 M ) toward the ionized clumps Ia, and another one (c4; mass ∼70 M ) toward the ionized clump Ib. A compact near-infrared (NIR) emission feature (extent ∼0.2 pc) is investigated toward the ionized clump Ia excited by an O8V-type star, and contains at least three embedded K-band stars. In the direction of the ionized clump Ia, the ALMA map also shows an elongated feature (extent ∼0.2 pc) hosting the cores c1-c3. All these findings together illustrate the existence of a small cluster of massive stars in the central hub. Considering the detection of the hub-filament morphology and the spatial locations of the mm cores, a global non-isotropic collapse (GNIC) scenario appears to be applicable in G25.4NW, which includes the basic ingredients of the global hierarchical collapse and clump-fed accretion models. Overall, the GNIC scenario explains the birth of massive stars in G25.4NW.

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Hub-filament System in IRAS 05480+2545: Young Stellar Cluster and 6.7 GHz Methanol Maser

Cited by 25 publications

References 53 publications

Unifying low- and high-mass star formation through density-amplified hubs of filaments

Unifying low- and high-mass star formation through density-amplified hubs of filaments

New Insights into the H ii Region G18.88–0.49: Hub–Filament System and Accreting Filaments

Unraveling the inner substructure of new candidate hub-filament system in the HII region G25.4NW

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