Structural studies of eight bright rimmed clouds in the southern hemisphere

Abstract

We carried out deep and wide-field near- and mid-infrared observations for a sample of 8 bright-rimmed clouds (BRCs). Supplemented with the $Spitzer$ archival data, we have identified and classified 44 to 433 young stellar objects (YSOs) associated with these BRCs. The Class I sources are generally located towards the places with higher extinction and are relatively closer to each other than the Class II sources, confirming that the young protostars are usually found in regions having denser molecular material. On the other hand the comparatively older population, Class II objects, are more randomly found throughout the regions, which can be due to their dynamical evolution. Using the minimal sampling tree analyses, we have extracted 13 stellar cores of 8 or more members, which contains 60\% of the total YSOs. The typical core is $\sim$0.6 pc in radii and somewhat elongated (aspect ratio of 1.45), of relatively low stellar density (surface density 60 pc${}^{-2}$), consisting of a small (35) number of YSOs of relatively young sources (66\% Class I ), and partially embedded (median $A_K$ =1.1 mag). But the cores show a wide range in their mass distribution ($\sim$20 to 2400 M${}_{\odot }$) with a median value of around 130 M${}_{\odot }$. We have found the star formation efficiencies in the cores to be between 3\% and 30\% with an average of $\sim$14\%, which agree with the efficiencies needed to link the core mass function to the initial mass function. We also found a linear relation between the density of the clouds and the number of YSOs. The peaked nearest neighbor spacing distributions of the YSOs and the ratio of Jeans lengths to the YSOs separations indicates a significant degree of non-thermally driven fragmentation in these BRCs.

arXiv comment43 pages, 25 figures, 6 tables, accepted for publishing in the Astronomical Journal. arXiv admin note: text overlap with arXiv:0906.0201, arXiv:1403.3082 by other authors

References in corpus (61)

• The Infrared Array Camera (IRAC) for the Spitzer Space Telescope
• Embedded Clusters in Molecular Clouds
• Disk Frequencies and Lifetimes in Young Clusters
• The Spitzer c2d Legacy Results: Star Formation Rates and Efficiencies; Evolution and Lifetimes
• Evolution of asymptotic giant branch stars II. Optical to far-infrared isochrones with improved TP-AGB models
• From filamentary clouds to prestellar cores to the stellar IMF: Initial highlights from the Herschel Gould Belt survey
• Mid-Infrared Selection of Active Galaxies
• The Wavelength Dependence of Interstellar Extinction from 1.25 to 8.0 microns Using GLIMPSE Data
• Interpreting Spectral Energy Distributions from Young Stellar Objects. I. A grid of 200,000 YSO model SEDs
• On the Star Formation Rates in Molecular Clouds
• A Spitzer Survey of Young Stellar Clusters within One Kiloparsec of the Sun: Cluster Core Extraction and Basic Structural Analysis
• Slow Star Formation in Dense Gas: Evidence and Implications
• The mass function of dense molecular cores and the origin of the IMF
• Spitzer Observations of NGC 1333: A Study of Structure and Evolution in a Nearby Embedded Cluster
• Infrared Extinction Toward Nearby Star-Forming Regions
• The statistical Analysis of Star Clusters
• The Role of Multiplicity in Disk Evolution and Planet Formation
• A Spitzer view of protoplanetary disks in the gamma Velorum cluster
• Intrinsically Red Sources observed by Spitzer in the Galactic Mid-Plane
• A Correlation Between Surface Densities of Young Stellar Objects and Gas in Eight Nearby Molecular Clouds
• The Initial Configuration of Young Stellar Clusters: A K-band Number Counts Analysis of the Surface Density of Stars
• A Catalog of Young Stellar Groups and Clusters Within 1kpc of the Sun
• The Spatial Structure of Young Stellar Clusters. I. Subclusters
• Clustered and Triggered Star Formation in W5: Observations with Spitzer
• A Pan-Carina YSO Catalog: Intermediate-Mass Young Stellar Objects in the Carina Nebula Identified Via Mid-Infrared Excess Emission
• A Combined Spitzer and Chandra Survey of Young Stellar Objects in the Serpens Cloud Core
• Dispersion in the lifetime and accretion rate of T Tauri discs
• The Spatial Evolution of Stellar Structures in the LMC
• Evolving structures of star-forming clusters
• Embedded Stellar Clusters in the W3/W4/W5 Molecular Cloud Complex
• Identifying Primordial Substructure in NGC 2264
• The structures of embedded clusters in the Perseus, Serpens and Ophiuchus molecular clouds
• Hierarchical Star-Formation in M33: Fundamental properties of the star-forming regions
• Triggered star formation in Bright-Rimmed Clouds: The Eagle Nebula revisited
• Interstellar matter and star formation in W5-E - A Herschel view
• HST/NICMOS Imaging Survey of the Ophiuchus (Lynds 1688) Cluster
• Spitzer observations of the Massive star forming complex S254-S258: structure and evolution
• A near-infrared study of the NGC 7538 star forming region
• Deep near-infrared observations of W3 Main star forming region
• Star formation in young star cluster NGC 1893
• Triggered Star Formation and Evolution of T-Tauri stars in and around Bright-Rimmed Clouds
• Observational study of sites of triggered star formation: CO and mid-infrared observations
• Stellar contents and star formation in the young star cluster Be 59
• Star formation in bright-rimmed clouds and cluster associated with W5 E H{\sc ii} region
• Mass functions and photometric binaries in nine open clusters
• Radio continuum and molecular line observations of four bright-rimmed clouds
• A SCUBA survey of bright-rimmed clouds
• A multiwavelength study of embedded clusters in W5-east, NGC7538, S235, S252 and S254-S258
• On the distribution of protostar masses
• The Clustering Behavior of Pre-Main Sequence Stars in NGC 346 in the Small Magellanic Cloud
• Young stellar population and ongoing star formation in the HII complex Sh2-252
• Optical photometric and polarimetric investigation of NGC 1931
• Young Stellar Population of the Bright-Rimmed Clouds BRC 5, BRC 7 and BRC 39
• High-mass star formation within the bright-rimmed cloud SFO 79
• A tale of two cores: Triggered massive star formation in the bright-rimmed cloud SFO 75
• Spitzer, Near-Infrared, and Submillimeter Imaging of the Relatively Sparse Young Cluster, Lynds 988e
• Collapse and expansion in the bright-rimmed cloud SFO 11NE
• Star formation activity in the Galactic H II region Sh2-297
• Investigation of the stellar content in the western part of the Carina nebula
• Multiwavelength Study of NGC 281 Region
• Escaping stars from young low-N clusters

Cited by in corpus (17)

• Global Hierarchical Collapse In Molecular Clouds. Towards a Comprehensive Scenario
• Thermal Jeans fragmentation within 1000 AU in OMC-1S
• The stellar contents and star formation in the NGC 7538 region
• The low-mass population in the young cluster Stock 8: Stellar properties and Initial Mass Function
• The disintegrating old open cluster Czernik 3
• Stellar cores in the Sh 2-305 H II region
• Young cluster Berkeley 59 : Properties, evolution and star formation
• Understanding formation of young, distributed low-mass stars and clusters in the W4 cloud complex
• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -XIII. Ongoing triggered star formation within clump-fed scenario found in the massive ($\sim 1500$ ${\mathrm{M}}_{\odot }$) clump
• Star formation and evolution of blister-type H{\sc ii} region Sh2-112
• Variable stars in the Sh 2-170 HII region
• Large scale star formation in Auriga region
• Investigation of Rocket Effect in BRC 18 using Gaia EDR3
• Investigation of Rocket Effect in Bright-Rimmed Clouds using Gaia EDR3
• Investigating the morphology and CO gas kinematics of Sh2-112 region
• Kronberger 55: A Candidate for End-dominated Collapse Scenario
• Long-term investigation of an open cluster Berkeley 65