Mid- and far-infrared properties of Spitzer Galactic bubbles revealed by the AKARI all-sky surveys

Abstract

We have carried out a statistical study on the mid- and far-infrared (IR) properties of Galactic IR bubbles observed by Spitzer. Using the Spitzer 8 $\mu \mathrm{m}$ images, we estimated the radii and covering fractions of their shells, and categorized them into closed, broken and unclassified bubbles with our data analysis method. Then, using the AKARI all-sky images at wavelengths of 9, 18, 65, 90, 140 and 160 $\mu \mathrm{m}$, we obtained the spatial distributions and the luminosities of polycyclic aromatic hydrocarbon (PAH), warm and cold dust components by decomposing 6-band spectral energy distributions with model fitting. As a result, 180 sample bubbles show a wide range of the total IR luminosities corresponding to the bolometric luminosities of a single B-type star to many O-type stars. For all the bubbles, we investigated relationships between the radius, luminosities and luminosity ratios, and found that there are overall similarities in the IR properties among the bubbles regardless of their morphological types. In particular, they follow a power-law relation with an index of $\sim$3 between the total IR luminosity and radius, as expected from the conventional picture of the Str$\ddot{\mathrm{o}}$mgren sphere. The exceptions are large broken bubbles; they indicate higher total IR luminosities, lower fractional luminosities of the PAH emission, and dust heating sources located nearer to the shells. We discuss the implications of those differences for a massive star-formation scenario.

arXiv comment59 pages, 15 figures (figs. 1, 3, 9, 10, 13 and 14 uploaded with low-resolution), accepted for publication in PASJ

References in corpus (36)

• The Spitzer Space Telescope Mission
• Infrared Emission from Interstellar Dust. IV. The Silicate-Graphite-PAH Model in the Post-Spitzer Era
• GLIMPSE: I. A SIRTF Legacy Project to Map the Inner Galaxy
• A new calibration of stellar parameters of Galactic O stars
• The Mid-Infrared Spectrum of Star-Forming Galaxies: Global Properties of PAH Emission
• The Infrared Astronomical Mission AKARI
• ATLASGAL - The APEX Telescope Large Area Survey of the Galaxy at 870 microns
• The VLA Galactic Plane Survey
• The Infrared Camera (IRC) for AKARI - Design and Imaging Performance
• Kinematic Distances to Molecular Clouds identified in the Galactic Ring Survey
• Do cloud-cloud collisions trigger high-mass star formation? I. Small cloud collisions
• Molecular clouds towards RCW 49 and Westerlund 2; Evidence for cluster formation triggered by cloud-cloud collision
• Dynamical Expansion of Ionization and Dissociation Front around a Massive Star. II. On the Generality of Triggered Star Formation
• Star formation around RCW 120, the perfect bubble
• Molecular Clouds Toward the Super Star Cluster NGC3603; Possible Evidence for a Cloud-Cloud Collision in Triggering the Cluster Formation
• Molecular Rings and the Thickness of Star-Forming Clouds
• The relations among 8, 24, and 160 micron dust emission within nearby spiral galaxies
• Cloud-cloud collision as a trigger of the high-mass star formation; a molecular line study in RCW120
• Star formation triggered by the Galactic HII region RCW 120: First results from the Herschel Space Observatory
• Temperature and Density Distribution in the Molecular Gas Toward Westerlund 2: Further Evidence for Physical Association
• Molecular clouds in the Trifid nebula M20; Possible evidence for a cloud-cloud collision in triggering the formation of the first generation stars
• The $AKARI$ Far-Infrared All-Sky Survey Maps
• Dynamical Expansion of Ionization and Dissociation Front around a Massive Star. I. A Mode of Triggered Star Formation
• Mopra CO Observations of the Bubble HII Region RCW120
• Triggered Star Formation and Dust around Mid-Infrared-Identified Bubbles
• IR Dust Bubbles II: Probing the Detailed Structure and Young Massive Stellar Populations of Galactic HII Regions
• Calibration of the AKARI Far-infrared All Sky Survey Maps
• Massive Star Forming Regions in the Galaxy using the Spitzer GLIMPSE Survey
• Testing Triggered Star Formation in Six H II Regions
• HII Region Driven Galactic Bubbles and Their Relationship to the Galactic Magnetic Field
• Molecular clumps and star formation associated with the infrared dust bubble N131
• Star formation around the mid-infrared bubble CN 148
• A statistical study of gaseous environment of Spitzer interstellar bubbles
• AKARI infrared imaging of reflection nebulae IC4954 and IC4955
• Multiple episodes of star formation in the CN15/16/17 molecular complex
• Large-scale mapping of the massive star-forming region RCW38 in the [CII] and PAH emission

Cited by in corpus (8)

• FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45 m telescope (FUGIN). VI. Dense gas and mini-starbursts in the W43 giant molecular cloud complex
• A star formation study of the ATLAS3D early-type galaxies with the AKARI all-sky survey
• A systematic study of Galactic infrared bubbles along the Galactic plane with AKARI and Herschel
• Infrared dust bubble CS51 and its interaction with the surrounding interstellar medium
• CO observations toward the isolated mid-infrared bubble S44: External triggering of O-star formation by a cloud-cloud collision
• Infrared Morphology of Regions of Ionized Hydrogen
• A systematic study of Galactic infrared bubbles along the Galactic plane with AKARI and Herschel. II. Spatial distributions of dust components around the bubbles
• Ammonia mapping observations of the Galactic infrared bubble N49: Three NH${}_3$ clumps along the molecular filament