Star formation in the filament of S254-S258 OB complex: a cluster in the process of being created

Samal, M. R.; Ojha, D. K.; Jose, Jessy; Zavagno, A.; Takahashi, Satoko; Neichel, Benoît; Kim, J. S.; Chauhan, Neelam; Pandey, A. K.; Зинченко, И. И.; Tamura, Motohide; Ghosh, S. K.

doi:10.1051/0004-6361/201322787

Cited by 28 publications

(33 citation statements)

References 130 publications

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“…Furthermore, the predicted collapse timescale coincides with the lifetime of Class I YSOs (∼0.5 Myr Evans et al 2009;Fang et al 2013). On small-scales, our results support the hypothesis that the formation of YSOs roughly agrees with the model of gravitational fragmentation, consistent with previous studies toward other filaments (Hartmann 2002;Samal et al 2015). Therefore, we suggest that turbulence controls large-scale fragmentation in the filament, while gravitational fragmentation plays an important role in YSOs fragmentation on small scales.…”

Section: Fragmentation In the Filament S287-mainsupporting

confidence: 92%

“…Thus, the critical line mass of S287-main is found to be 27 M pc −1 . Following previous studies (e.g., André et al 2010;Arzoumanian et al 2011;Samal et al 2015), we first investigated the radial profile perpendicular to the highest H 2 column density line, and then used a Gaussian fit to the radial A104, page 14 of 25 profiles. We find a characteristic width of 1.8 pc.…”

Section: Fragmentation In the Filament S287-mainmentioning

confidence: 99%

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Molecular clouds and star formation toward the Galactic plane within 216.25° ≤l≤ 218.75° and −0.75° ≤b≤ 1.25°

Gong

Mao

Fang

et al. 2016

A&A

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Context. Molecular clouds trace the spiral arms of the Milky Way and all its star forming regions. Large-scale mapping of molecular clouds will provide an approach to understand the processes that govern star formation and molecular cloud evolution. Aims. As a part of the Milky Way Imaging Scroll Painting (MWISP) survey, the aim is to study the physical properties of molecular clouds and their associated star formation toward the Galactic plane within 216.25• ≤ l ≤ 218.75• and −0.75• , which covers the molecular cloud complex S287. Methods. Using the 3 × 3 Superconducting Spectroscopic Array Receiver (SSAR) at the PMO-13.7m telescope, we performed a simultaneous 12 CO (1-0), 13 CO (1-0), C 18 O (1-0) mapping toward molecular clouds in a region encompassing 3.75 square degrees. We also make use of archival data to study star formation within the molecular clouds. Results. We reveal three molecular clouds, the 15 km s −1 cloud, the 27 km s −1 cloud, and the 50 km s −1 cloud, in the surveyed region. The 50 km s −1 cloud is resolved with an angular resolution of ∼1 for the first time. Investigating their morphology and velocity structures, we find that the 27 km s −1 cloud is likely affected by feedback from the stellar association Mon OB3 and the 50 km scloud is characterized by three large expanding molecular shells. The surveyed region is mapped in C 18 O (1-0) for the first time. We discover seven C 18 O clumps that are likely to form massive stars, and 15 dust clumps based on the Bolocam Galactic Plane Survey (BGPS) archive data. Using infrared color-color diagrams, we find 56 Class I and 107 Class II young stellar object (YSO) candidates toward a slightly larger region of 5.0 square degrees. Based on the distribution of YSO candidates, an overdensity is found around the HII region S287 and the intersection of two shells; this is probably indicative of triggering. The star formation efficiency (SFE) and rate (SFR) of the 27 km s −1 cloud are discussed. Comparing the observed values of the filament S287-main with fragmentation models, we suggest that turbulence controls the large-scale fragmentation in the filament, while gravitational fragmentation plays an important role in the formation of YSOs on small scales. We find that star-forming gas tends to have a higher excitation temperature, a higher 13 CO (1-0) opacity, and a higher column density than non-star-forming gas, which is consistent with the point that star formation occurs in denser gas and star-forming gas is heated by YSOs. Using the 1.1 mm dust emission to trace dense gas, we obtain a dense gas fraction of 2.7-10.4% for the 27 km s −1 cloud.Key words. surveys -ISM: clouds -stars: formation -radio lines: ISM -ISM: kinematics and dynamics IntroductionMolecular clouds are also known as stellar nurseries because they are the densest parts of the interstellar medium that may gravitationally collapse, and thus create protostars (e.g., Shu et al. 1987;Kennicutt & Evans 2012). Molecular clouds comprise a significant fraction of the total mass of in...

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Section: Fragmentation In the Filament S287-mainsupporting

confidence: 92%

Section: Fragmentation In the Filament S287-mainmentioning

confidence: 99%

Molecular clouds and star formation toward the Galactic plane within 216.25° ≤l≤ 218.75° and −0.75° ≤b≤ 1.25°

Gong

Mao

Fang

et al. 2016

A&A

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“…The completeness limits at various bands were estimated from histogram turn over method (e.g., Ohlendorf et al 2013;Samal et al 2015). Figure 2 dis-3 http://archive.spitzer.caltech.edu/ plays the cumulative logarithmic distribution of sources at different wavebands.…”

Section: Spitzer-irac Datamentioning

confidence: 99%

“…Schneider et al 2012;Kirk et al 2013). As molecular clouds are often comprised of H ii regions, bubbles, and dense filamentary structures (Bieging et al 2009;Mallick et al 2013;Samal et al 2015;Bieging et al 2016;Jose et al 2017), therefore, understanding what shapes the molecular clouds to dense and massive enough to form a young cluster is of great inter-est. Additionally, the initial cloud configuration decides the future location of cluster formation (e.g.…”

Section: Introductionmentioning

confidence: 99%

The Planck Cold Clump G108.37-01.06: A Site of Complex Interplay between H ii Regions, Young Clusters, and Filaments

Dutta

Mondal

Samal

et al. 2018

ApJ

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The Planck Galactic Cold Clumps (PGCCs) are the possible representations of the initial conditions and the very early stages of star formation. With an objective to understand better the star and star cluster formation, we probe the molecular cloud associated with PGCC G108.37-01.06 (hereafter, PG108.3), which can be traced in a velocity range −57 to −51 km s −1 . The IPHAS images reveal Hα emission at various locations around PG108.3, and optical spectroscopy of the bright sources in those zones of Hα emission disclose two massive ionizing sources with spectral type O8-O9V and B1V. Using the radio continuum, we estimate ionizing gas parameters and find the dynamical ages of H ii regions associated with the massive stars in the range 0.5−0.75 Myr. Based on the stellar surface density map constructed from the deep near-infrared CHFT observations, we find two prominent star clusters in PG108.3; of which, the cluster associated with H ii region S148 is moderately massive (∼ 240 M⊙). A careful inspection of JCMT 13 CO(3−2) molecular data exhibits that the massive cluster is associated with a number of filamentary structures. Several embedded young stellar objects (YSOs) are also identified in the PG108.3 along the length and junction of filaments. We find the evidence of velocity gradient along the length of the filaments. Along with kinematics of the filaments and the distribution of ionized, molecular gas and YSOs, we suggest that the cluster formation is most likely due to the longitudinal collapse of the most massive filament in PG108.3.

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“…Multiwavelength studies of these young stellar objects (YSOs) provide unique opportunity to understand their formation, evolution over time, circumstellar discs including planet formation in their discs, environment induced formation scenario and history (e.g. Carpenter et al 2001;Kenyon S., & Hartman 1995;Evans et al 2009;Lada et al 2010;Jose et al 2012Jose et al , 2013Samal et a. 2015).…”

Section: Introductionmentioning

confidence: 99%

The young cluster NGC 2282: a multiwavelength perspective

Dutta¹,

Mondal²,

Jose³

et al. 2015

Mon. Not. R. Astron. Soc.

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We present the analysis of the stellar content of NGC 2282, a young cluster in the Monoceros constellation, using deep optical BV I and IPHAS photometry along with infrared (IR) data from UKIDSS and Spitzer-IRAC. Based on the stellar surface density analysis using nearest neighborhood method, the radius of the cluster is estimated as ∼ 3.15 ′ . From optical spectroscopic analysis of 8 bright sources, we have classified three early B-type members in the cluster, which includes, HD 289120, a previously known B2V type star, a Herbig Ae/Be star (B0.5 Ve) and a B5 V star. From spectrophotometric analyses, the distance to the cluster has been estimated as ∼ 1.65 kpc. The K-band extinction map is estimated using nearest neighborhood technique, and the mean extinction within the cluster area is found to be A V ∼ 3.9 mag. Using IR colour-colour criteria and H α -emission properties, we have identified a total of 152 candidate young stellar objects (YSOs) in the region, of which, 75 are classified as Class II, 9 are Class I YSOs. Our YSO catalog also includes 50 H α -emission line sources, identified using slitless spectroscopy and IPHAS photometry data. Based on the optical and near-IR colour-magnitude diagram analyses, the cluster age has been estimated to be in the range of 2 − 5 Myr, which is in agreement with the estimated age from disc fraction (∼ 58%). Masses of these YSOs are found to be ∼ 0.1−2.0 M ⊙ . Spatial distribution of the candidate YSOs shows spherical morphology, more or less similar to the surface density map.

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Star formation in the filament of S254-S258 OB complex: a cluster in the process of being created

Cited by 28 publications

References 130 publications

Molecular clouds and star formation toward the Galactic plane within 216.25° ≤l≤ 218.75° and −0.75° ≤b≤ 1.25°

Molecular clouds and star formation toward the Galactic plane within 216.25° ≤l≤ 218.75° and −0.75° ≤b≤ 1.25°

The Planck Cold Clump G108.37-01.06: A Site of Complex Interplay between H ii Regions, Young Clusters, and Filaments

The young cluster NGC 2282: a multiwavelength perspective

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