Optical and mid-infrared neon abundance determinations in star-forming regions

Subarcsecond radio and infrared observations reveal a class of luminous, obscured, optically thick HII regions associated with extremely large young clusters in nearby starburst galaxies. VLA images show bright radio nebulae with ne ∼ 104 cm−3, densities characteristic of young Galactic compact HII regions. Excitation of the nebulae requires the presence of several thousand O stars within regions of 1-10 pc extent, corresponding to clusters containing 105–106 stars. The compact nebulae are also bright in the mid-infrared, and can for significant fractions of not only the total IR luminosity, but also the total bolometric luminosity, of the parent galaxies. The prototype for these “supernebulae” is the large, obscured cluster in the dwarf galaxy NGC 5253.

Download Full-text

UCHII regions in the Antennae

Proceedings of the International Astronomical Union ◽

10.1017/s1743921307002645 ◽

2006 ◽

Vol 2 (S237) ◽

pp. 476-476

Author(s):

L. Snijders ◽

L. J. Kewley ◽

P. P. van der Werf ◽

B. R. Brandl

Keyword(s):

Emission Line ◽

Spatial Resolution ◽

Average Density ◽

Physical Characteristics ◽

Stellar Clusters ◽

Mid Infrared ◽

Infrared Observations ◽

Star Forming ◽

Compact Material ◽

Star Forming Regions

AbstractWe explore the physical characteristics of young stellar clusters in the Antennae by combining recent ground- and space-based mid-infrared observations with a newly developed set of diagnostic diagrams. Spitzer data give an overview of the star-forming regions extending over hundreds of parsecs, showing a dominant diffuse ISM component with a density of 102 cm−3 plus a small fraction of very compact material (106 cm−3). With its higher spatial resolution VISIR gives a close-up view of the latter component. Its emission line ratios suggest that these regions are fundamentally different from local star-forming regions. Instead of having small isolated UCHII regions, as in local star-forming regions, the average density of the medium of the whole region falls in the (ultra)compact regime, exceeding 104 cm−3 over tens of parsecs.

Download Full-text

Drama of HII regions: Clustered and Triggered Star Formation

Proceedings of the International Astronomical Union ◽

10.1017/s1743921315008935 ◽

2015 ◽

Vol 12 (S316) ◽

pp. 129-130

Author(s):

Jin-Zeng Li ◽

Jinghua Yuan ◽

Hong-Li Liu ◽

Yuefang Wu ◽

Ya-Fang Huang

Keyword(s):

Star Formation ◽

Hii Regions ◽

Radio Telescopes ◽

Physical Status ◽

Mid Infrared ◽

Star Forming ◽

Star Forming Regions ◽

Dense Cores ◽

Compressed Gas ◽

Multi Wavelength

AbstractIn order to understand the star formation process under the influence of H ii regions, we have carried out extensive investigations to well selected star-forming regions which all have been profoundly affected by existing massive O type stars. On the basis of multi-wavelength data from mid-infrared to millimeter collected using Spitzer, Herschel, and ground based radio telescopes, the physical status of interstellar medium and star formation in these regions have been revealed. In a relatively large infrared dust bubble, active star formation is undergoing and the shell is still expanding. Signs of compressed gas and triggered star formation have been tentatively detected in a relatively small bubble. The dense cores in the Rosette Molecular Complex detected at 1.1 mm using SMA have been speculated to have a likely triggered origin according to their spatial distribution. Although some observational results have been obtained, more efforts are necessary to reach trustworthy conclusions.

Download Full-text

Magnetic field structures in star-forming regions: mid-infrared imaging polarimetry of K3-50

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stv1272 ◽

2015 ◽

Vol 453 (3) ◽

pp. 2623-2637 ◽

Cited By ~ 6

Author(s):

Peter Barnes ◽

Dan Li ◽

Charles Telesco ◽

Nahathai Tanakul ◽

Naibí Mariñas ◽

...

Keyword(s):

Magnetic Field ◽

Infrared Imaging ◽

Mid Infrared ◽

Star Forming ◽

Star Forming Regions ◽

Imaging Polarimetry

Download Full-text

A QUALITY CHECK OF THE AKARI MID-INFRARED ALL-SKY DIFFUSE MAP TOWARD THE MASSIVE STAR-FORMING REGIONS NGC 6334 AND NGC 6357

Publications of The Korean Astronomical Society ◽

10.5303/pkas.2017.32.1.021 ◽

2017 ◽

Vol 32 (1) ◽

pp. 21-23

Author(s):

Hidetoshi Sano ◽

Tomoya Amatsutsu ◽

Toru Kondo ◽

Keichiro Nakamichi ◽

Mitsuyoshi Yamagishi ◽

...

Keyword(s):

Massive Star ◽

Mid Infrared ◽

Star Forming ◽

Star Forming Regions ◽

Quality Check ◽

Ngc 6334

Download Full-text

A HIGH SPATIAL RESOLUTION MID-INFRARED SPECTROSCOPIC STUDY OF THE NUCLEI AND STAR-FORMING REGIONS IN LUMINOUS INFRARED GALAXIES

The Astrophysical Journal ◽

10.1088/0004-637x/711/1/328 ◽

2010 ◽

Vol 711 (1) ◽

pp. 328-349 ◽

Cited By ~ 41

Author(s):

Tanio Díaz-Santos ◽

Almudena Alonso-Herrero ◽

Luis Colina ◽

Christopher Packham ◽

N. A. Levenson ◽

...

Keyword(s):

Spectroscopic Study ◽

Spatial Resolution ◽

High Spatial Resolution ◽

Infrared Spectroscopic Study ◽

Infrared Galaxies ◽

Mid Infrared ◽

Star Forming ◽

Luminous Infrared Galaxies ◽

Star Forming Regions ◽

Infrared Spectroscopic

Download Full-text

Properties of polycyclic aromatic hydrocarbons in the star forming environment in nearby galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308021662 ◽

2008 ◽

Vol 4 (S251) ◽

pp. 241-246

Author(s):

Itsuki Sakon ◽

Takashi Onaka ◽

Daisuke Kato ◽

Hidehiro Kaneda ◽

Hirokazu Kataza ◽

...

Keyword(s):

Aromatic Hydrocarbons ◽

Mid Infrared ◽

Active Star ◽

Star Forming ◽

Star Forming Regions ◽

Ngc 6946 ◽

Polycyclic Aromatic ◽

Nearby Galaxies ◽

Ionization Model ◽

Photo Ionization

AbstractWe have carried out the mid-infrared slit spectroscopic observations of sources in the LMC and in NGC 6946 with AKARI/IRC. We investigate the properties of the UIR bands in terms of the star forming activities. We find systematically larger ratios of UIR bands in 6–9 μm to 11.2 μm band in active star forming regions than in the quiet regions. This behavior is consistent with the photo-ionization model of PAHs. Our results suggest that the ratios of UIR bands in 6–9 μm to 11.2 μm band can be used as more efficient and vigorous tools to measure the extent of on-going star formation in remote galaxies rather than just the presence or absence of the features themselves.

Download Full-text