Filamentary Structures and Star Formation Activity in the Sites S234, V582, and IRAS 05231+3512

Dewangan, L. K.; Baug, Tapas; Ojha, D. K.; Зинченко, И. И.; Luna, A.

doi:10.3847/1538-4357/aad4b1

Cited by 14 publications

(25 citation statements)

References 58 publications

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“…With the help of the Herschel N (H 2 ) map, the total mass of the shell-like feature is determined to be ∼2.9 ×10 4 M using the equation M area = µ H2 m H A pix ΣN (H 2 ), where µ H2 is defined earlier (i.e., 2.8), A pix is the area subtended by one pixel (i.e., 6 /pixel), and ΣN (H 2 ) is the total column density (see also Dewangan et al 2017a, for more details of the analysis). The clumpfind IDL program is employed to estimate the value of ΣN (H 2 ) (e.g., Dewangan et al 2017cDewangan et al , 2018b.…”

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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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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“…IC 443: Both the shocked Hi and H2 gases are mostly confined to an extended partial shell in the southern area (see Figure 1). G172.8+1.5: There are MCs in this area, but there is no evidence for the interaction between the SNR and the MCs (Kang et al 2012; see also Dewangan et al 2018). G190.2+1.1: MCs can be seen around the SNR in the CfA CO survey (Dame et al 2001), but there is no evidence for the interaction. )…”

Section: Tablementioning

confidence: 95%

Radiative Supernova Remnants and Supernova Feedback

Koo,

Kim,

Park

et al. 2020

Preprint

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Supernova (SN) explosions are a major feedback mechanism regulating star formation in galaxies through their momentum input. We review the observations of SNRs in radiative stages in the Milky Way to validate the theoretical results on the momentum/energy injection from a single SN explosion. For seven SNRs where we can observe fast-expanding, atomic radiative shells, we show that the shell momentum inferred from Hi 21 cm line observations is in the range of (0.5-4.5)×10 5 M km s −1 . In two SNRs (W44 and IC 443), shocked molecular gas with momentum comparable to that of the atomic SNR shells has been also observed. We compare the momentum and kinetic/thermal energy of these seven SNRs with the results from 1D and 3D numerical simulations. The observation-based momentum and kinetic energy agree well with the expected momentum/energy input from an SN explosion of ∼ 10 51 erg. It is much more difficult to use data/model comparisons of thermal energy to constrain the initial explosion energy, however, due to rapid cooling and complex physics at the hot/cool interface in radiative SNRs. We discuss the observational and theoretical uncertainties of these global parameters and explosion energy estimates for SNRs in complex environments.

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“…To compute the mass of the filament/clump, we employed the equation, Marea = µH 2 mH AreapixΣN (H2), where µH 2 is the mean molecular weight per hydrogen molecule (i.e., 2.8), Areapix is the area subtended by one pixel (i.e., 6 /pixel), and ΣN (H2) is the total column density (see also Dewangan et al 2017a). Following the works of Dewangan et al (2018b), we have estimated the line mass or mass per unit length (i.e., M line,obs ∼3000 M pc −1 ) and the critical line mass (M line,crit ) of the filament "fs1". Due to unknown inclination angle of the filament, we consider the observed line mass as an upper limit.…”

Section: Dust Temperature and Column Density Mapsmentioning

confidence: 99%

Uncovering distinct environments in an extended physical system around the W33 complex

Dewangan

Baug

Ojha

2020

Monthly Notices of the Royal Astronomical Society

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ABSTRACT We present a multiwavelength investigation of a large-scale physical system containing the W33 complex. The extended system (∼50 pc × 37 pc) is selected based on the distribution of molecular gas at [29.6, 60.2] km s−1 and of 88 ATLASGAL 870-μm dust clumps at d ∼2.6 kpc. The extended system/molecular cloud traced in the maps of 13CO and C18O emission contains several H ii regions excited by OB stars (age ∼0.3–1.0 Myr) and a thermally supercritical filament (fs1, length ∼17 pc). The filament, which is devoid of ionized gas, shows a dust temperature (Td) of ∼19 K, while the H ii regions have a Td of ∼21–29 K. It suggests the existence of two distinct environments in the cloud. The distribution of Class I young stellar objects (mean age ∼0.44 Myr) traces the early stage of star formation (SF) towards the cloud. At least three velocity components (around 35, 45 and 53 km s−1) are investigated towards the system. The analysis of 13CO and C18O reveals spatial and velocity connections of cloud components at around 35 and 53 km s−1. The observed positions of previously known sources, W33 Main, W33 A and O4–7I stars, are found towards a complementary distribution of these two cloud components. The filament fs1 and a previously known object W33 B are seen towards the overlapping areas of the clouds, where ongoing SF activity is evident. A scenario related to converging/colliding flows from two different velocity components appears to explain well the observed indications of SF activity in the system.

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Filamentary Structures and Star Formation Activity in the Sites S234, V582, and IRAS 05231+3512

Cited by 14 publications

References 58 publications

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

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

Radiative Supernova Remnants and Supernova Feedback

Uncovering distinct environments in an extended physical system around the W33 complex

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