Molecular gas in high-mass filament WB673

Kirsanova, M. S.; Салий, С. В.; Соболев, А. М.; Olofsson, A. O. H.; Ladeyschikov, D. A.; Thomasson, Magnus

doi:10.1515/astro-2017-0020

Cited by 13 publications

(10 citation statements)

References 31 publications

(89 reference statements)

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“…This quantitative analysis indicates the intense star formation activity in the thermally supercritical filament ns1. 2017) also reported a similar extended shell-like structure/bubble-shaped nebula in the same longitude direction (see Figure 5 in Kang et al 2012, and Figure 1 in Kirsanova et al 2017). In Figure 17b, the Galactic southern side of the extended structure is also presented using the Herschel 500 µm image, where our selected star-forming regions (i.e.…”

Section: Embedded Condensations In the Filament Ns1supporting

confidence: 62%

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

Dewangan

Baug

Ojha

et al. 2018

ApJ

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To investigate the physical processes, we present observational results of the sites S234, V582, and IRAS 05231+3512 situated toward l = 171 • .7-174 • .1. Based on the CO line data, we find that these sites are not physically connected, and contain at least one filament (with length > 7 pc). The observed line masses (M line,obs ) of the filaments associated with V582 and IRAS 05231+3512 are ∼37 and ∼28 M pc −1 , respectively. These filaments are characterized as thermally supercritical, and harbor several clumps. Groups of infrared-excess sources and massive B-type stars are observed toward the filament containing V582, while a very little star formation (SF) activity is found around IRAS 05231+3512. Our results favour radial collapse scenario in the filaments harboring V582 and IRAS 05231+3512. In the site S234, two filaments (i.e. ns1 (M line,obs ∼130 M pc −1 ) and ns2 (M line,obs ∼45 M pc −1 )) are identified as thermally supercritical. An extended temperature structure at 27-30 K surrounds a relatively cold (∼19 K) ∼8.9 pc long filament ns1. At least four condensations (M clump ∼70-300 M ) are seen in ns1, and are devoid of the GMRT 610 MHz radio emission. The filament ns2 hosting clumps is devoid of ongoing SF, and could be at an early stage of fragmentation. An intense SF activity, having the SF efficiency ∼3.3% and SF rate ∼40-20 M Myr −1 (for t sf ∼1-2 Myr), is observed in ns1. The feedback of massive stars in S234 seems to explain the observed SF in the filament ns1.

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Section: Embedded Condensations In the Filament Ns1supporting

confidence: 62%

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

Dewangan

Baug

Ojha

et al. 2018

ApJ

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“…The configuration, commonly described as 'pearls on a string', was initially seen in infrared data from the Herschel space telescope (Arzoumanian et al 2011) and has since been recognised as a common feature of star formation. On the other hand, filaments of much larger scales have been found in other star forming regions such as NGC 6334 (Zernickel et al 2013), and gas bridges of a similar scale to those in S235 connect multiple developed HII regions in OMC-1 (Hacar et al 2017) and the large filament observed in molecular gas in WB673 (Kirsanova et al 2017). However the nature of the aforementioned filamentary systems differs markedly from those seen in S235, which instead connect clusters of YSOs rather than individual protostars, and have formed in the presence of-, and by interaction with-a single HII region.…”

Section: Ammonia Gas Bridges As Remnants Of Induced Fragmentationmentioning

confidence: 92%

NH3 observations of the S235 star-forming region: Dense gas in inter-core bridges

Burns

Handa

Omodaká

et al. 2019

Publications of the Astronomical Society of Japan

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Star formation is thought to be driven by two groups of mechanisms; spontaneous collapse and triggered collapse. Triggered star formation mechanisms further diverge into cloud-cloud collision (CCC), "collect and collapse" (C&C) and shock induced collapse of pre-existing, gravitationally stable cores, or 'radiation driven implosion' (RDI). To evaluate the contributions of these mechanisms and establish whether these processes can occur together within the same star forming region we performed mapping observations of radio frequency ammonia, and water maser emission lines in the S235 massive star forming region. Via spectral analyses of main, hyperfine and multi-transitional ammonia lines we explored the distribution of temperature and column density in the dense gas in the S235 and S235AB star forming region. The most remarkable result of the mapping observations is the discovery of high density gas in inter-core bridges which physically link dense molecular cores that house young proto-stellar clusters. The presence of dense gas implies the potential for future star formation within the system of cores and gas bridges. Cluster formation implies collapse and the continuous physical links, also seen in re-imaged archival CS and 13 CO maps, suggests a common origin to the molecular cores housing these clusters, i.e the structure condensed from a single, larger parent cloud, brought about by the influence of a local expanding HII region. An ammonia absorption feature co-locating with the center of the extended HII region may be attributed to an older gas component left over from the period prior to formation of the HII region. Our observations also detail known and new sites of water maser emission, highlighting regions of active ongoing star formation.

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“…Considering the locations of these sources, it is possible that they trace peculiar motions or flows associated with the Perseus spiral arm. Kirsanova et al (2017) found that high-mass star forming regions (HMSFRs) in the Perseus arm traced by 6.7 GHz methanol masers between 85 • < l < 124 • , and 173 • < l < 196 • are moving outward and rotate about the Galaxy at a higher velocity with respect to the gas tracers (CO and CS). As can be seen in Figure 7 of Kirsanova et al (2017), the kinematics of these HMSFRs are somewhat simiar to our group C SiO masers, which supports our viewpoint that there exist large scale peculiar motions in the Perseus arm.…”

Section: Moving Groups and High Speed Starsmentioning

confidence: 99%

SiO maser survey towards off-plane O-rich AGBs around the orbital plane of the Sagittarius stellar stream

Wu¹,

Matsunaga²,

Burns³

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We conducted an SiO maser survey towards 221 O-rich AGB stars with the aim of identifying maser emission associated with the Sagittarius stellar stream. In this survey, maser emission was detected in 44 targets, of which 35 were new detections. All of these masers are within 5 kpc of the Sun. We also compiled a Galactic SiO maser catalogue including ∼2300 SiO masers from the literature. The distribution of these SiO masers give a scale height of 0.40 kpc, while 42 sources deviate from the Galactic plane by more than 1.2 kpc, half of which were found in this survey. Regarding SiO masers in the disc, we found both the rotational speeds and the velocity dispersions vary with the Galactic plane distance. Assuming Galactic rotational speed Θ 0 = 240 km s −1 , we derived the velocity lags are 15 km s −1 and 55 km s for disc and off-plane SiO masers respectively. Moreover, we identified three groups with significant peculiar motions (with 70% confidence). The most significant group is in the thick disc that might trace stream/peculiar motion of the Perseus arm. The other two groups are mainly made up of off-plane sources. The northern and southern off-plane sources were found to be moving at ∼ 33 km s −1 and 54 km s −1 away from the Galactic plane, respectively. Causes of these peculiar motions are still unclear. For the two off-plane groups, we suspect they are thick disc stars whose kinematics affected by the Sgr stellar stream or very old Sgr stream debris.

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Molecular gas in high-mass filament WB673

Cited by 13 publications

References 31 publications

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

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

NH3 observations of the S235 star-forming region: Dense gas in inter-core bridges

SiO maser survey towards off-plane O-rich AGBs around the orbital plane of the Sagittarius stellar stream

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