Star-forming sites IC 446 and IC 447: an outcome of end-dominated collapse of Monoceros R1 filament

Abstract

We present an analysis of multi-wavelength observations of Monoceros R1 (Mon R1) complex (at d ~760 pc). An elongated filament (length ~14 pc, mass ~1465 Msun) is investigated in the complex, which is the most prominent structure in the Herschel column density map. An analysis of the FUGIN 12CO(1-0) and 13CO(1-0) line data confirms the existence of the filament traced in a velocity range of [-5, +1] km/s. The filament is found to host two previously known sites IC 446 and IC 447 at its opposite ends. A massive young stellar object (YSO) is embedded in IC 446, while IC 447 contains several massive B-type stars. The Herschel temperature map reveals the extended warm dust emission (at T_d ~ 15-21 K) toward both the ends of the filament. The Spitzer ratio map of 4.5 micron/3.6 micron emission suggests the presence of photo-dissociation regions and signature of outflow activity toward IC 446 and IC 447. Based on the photometric analysis of point-like sources, clusters of YSOs are traced mainly toward the filament ends. The filament is found to be thermally supercritical showing its tendency of fragmentation, which is further confirmed by the detection of a periodic oscillatory pattern (having a period of ~3-4 pc) in the velocity profile of 13CO. Our outcomes suggest that the fragments distributed toward the filament ends have rapidly collapsed, and had formed the known star-forming sites. Overall, the elongated filament in Mon R1 is a promising sample of the "end-dominated collapse" scenario, as discussed by Pon et al. (2011, 2012).

17 pages, 9 figures, 2 tables, Accepted for publication The Astrophysical Journal

References in corpus (16)

• The UKIRT Infrared Deep Sky Survey (UKIDSS)
• A Spitzer Survey of Young Stellar Clusters within One Kiloparsec of the Sun: Cluster Core Extraction and Basic Structural Analysis
• Filamentary structure of star-forming complexes
• FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45-m telescope (FUGIN) I: Project Overview and Initial Results
• Cooling, Gravity and Geometry: Flow-driven Massive Core Formation
• Multi-temperature mapping of dust structures throughout the Galactic Plane using the PPMAP tool with Herschel Hi-GAL data
• The Bones of the Milky Way
• Aspect Ratio Dependence of the Free-Fall Time for Non-Spherical Symmetries
• Investigating the Global Collapse of Filaments Using Smoothed Particle Hydrodynamics
• Multi-wavelength study of the star-formation in the S237 H II region
• Observational signatures of end-dominated collapse in the S242 filamentary structure
• New insights in the mid-infrared bubble N49 site: a clue of collision of filamentary molecular clouds
• Hub-filament system in IRAS 05480+2545: young stellar cluster and 6.7 GHz methanol maser
• The molecular cloud S242: physical environment and star formation activities
• The physical environment around IRAS 17599-2148: infrared dark cloud and bipolar nebula
• Embedded filaments in IRAS 05463+2652: early stage of fragmentation and star formation activities

Cited by in corpus (3)

• Simultaneous evidence of edge collapse and hub-filament configurations: A rare case study of a Giant Molecular Filament G45.3+0.1
• Monoceros OB4: a new association in Gaia DR2
• A Gaia view on the star formation in the Monoceros OB1 and R1 associations