Spatial distribution of star formation related to ionized regions throughout the inner Galactic plane

Abstract

We present a comprehensive statistical analysis of star-forming objects located in the vicinities of 1 360 bubble structures throughout the Galactic Plane and their local environments. The compilation of ~70 000 star-forming sources, found in the proximity of the ionized (Hii) regions and detected in both Hi-GAL and GLIMPSE surveys, provided a broad overview of the different evolutionary stages of star-formation in bubbles, from prestellar objects to more evolved young stellar objects (YSOs). Surface density maps of star-forming objects clearly reveal an evolutionary trend where more evolved star-forming objects are found spatially located near the center, while younger star-forming objects are found at the edge of the bubbles. We derived dynamic ages for a subsample of 182 Hii regions for which kinematic distances and radio continuum flux measurements were available. We detect ~80% more star-forming sources per unit area in the direction of bubbles than in the surrounding fields. We estimate ~10% clump formation efficiency (CFE) of Hi-GAL clumps in bubbles, twice the CFE in fields not affected by feedback. We find higher CFE of protostellar clumps in younger bubbles, whose density of the bubble shells is higher. We argue that the formation rate from prestellar to protostellar phase is probably higher during the early stages of the bubble expansion. Evaluation of the fragmentation time inside the shell of bubbles advocates the preexistence of clumps in the medium before the bubble, as supported by numerical simulations. Approximately 23% of the Hi-GAL clumps are found located in the direction of a bubble, with 15% for prestellar clumps and 41% for protostellar clumps. We argue that the high fraction of protostellar clumps may be due to the acceleration of the star-formation process cause by the feedback of the (Hii) bubbles.

15 pages, 12 figures. Accepted for publication by Astronomy and Astrophysics

References in corpus (16)

• Theory of Star Formation
• Infrared Emission from Interstellar Dust. IV. The Silicate-Graphite-PAH Model in the Post-Spitzer Era
• Cold Dark Clouds: The Initial Conditions for Star Formation
• A Spitzer Survey of Young Stellar Clusters within One Kiloparsec of the Sun: Cluster Core Extraction and Basic Structural Analysis
• MAMBO Mapping of Spitzer c2d Small Clouds and Cores
• Spitzer Observations of NGC 1333: A Study of Structure and Evolution in a Nearby Embedded Cluster
• The earliest phases of high-mass star formation: a 3 square degree millimeter continuum mapping of Cygnus X
• Intrinsically Red Sources observed by Spitzer in the Galactic Mid-Plane
• Properties of Hi-GAL clumps in the inner Galaxy]{The Hi-GAL compact source catalogue. I. The physical properties of the clumps in the inner Galaxy ($-71.0^{\circ }<\ell <67.0^{\circ }$)
• The identification of filaments on far infrared and submillimiter images. Morphology, physical conditions and relation with star formation of filamentary structure
• A 24 Micron Point Source Catalog of the Galactic Plane from Spitzer/MIPSGAL
• The dangers of being trigger--happy
• The molecular complex associated with the Galactic HII region Sh2-90: a possible site of triggered star formation
• A feedback-driven bubble G24.136+00.436: a possible site of triggered star formation
• Deep near-infrared adaptive optics observations of a young embedded cluster at the edge of the RCW 41 HII region
• The YSO Population in the Vela-D Molecular Cloud

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