Central free-free dominated 880-μm emission in II Zw 40

Hirashita, Hiroyuki

doi:10.1111/j.1365-2966.2011.19535.x

Cited by 5 publications

(12 citation statements)

References 88 publications

(167 reference statements)

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“…6-b1). Submillimetre array (SMA) observations at 880µm (Hirashita 2011) and MRT observations at 1.25 mm (Albrecht et al 2004) are in very nice agreement with our fit, while 850µm SCUBA and 1.3mm MAMBO observations by Galliano et al (2005) and Hunt et al (2005a) are not. It is possible that differences in observed fluxes are due to the fact that II Zw 40 is located at low Galactic latitude with a high Milky Way extinction.…”

Section: Dust-to-gas Mass Ratiosupporting

confidence: 82%

Dust emission in star-forming dwarf galaxies: General properties and the nature of the submm excess

Izotov

Гусева

Fricke

et al. 2014

A&A

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We studied the global characteristics of dust emission in a large sample of emission-line star-forming galaxies. The sample consists of two subsamples. One subsample (SDSS sample) includes ∼4000 compact star-forming galaxies from the Sloan Digital Sky Survey (SDSS), which were also detected in all four bands at 3.4 μm, 4.6 μm, 12 μm, and 22 μm of the WISE all-sky survey. The second subsample (Herschel sample) is a sample of 28 compact star-forming galaxies observed with Herschel in the FIR range. Data of the Herschel sample were supplemented by the photometric data from the Spitzer observations, GALaxy Evolution Explorer (GALEX) survey, SDSS, Wide-Field Infrared Survey Explorer (WISE), Two Micron All Sky Survey (2MASS), NRAO VLA Sky Survey (NVSS), and Faint Images of the Radio Sky at Twenty-cm (FIRST) survey, as well as optical and Spitzer spectra and data in submm and radio ranges. It is found that warm dust luminosities of galaxies from the SDSS sample and cold and warm dust luminosities of galaxies from the Herschel sample are strongly correlated with Hβ luminosities, which implies that one of the main sources of dust heating in star-forming galaxies is ionising UV radiation of young stars. Likely, a significant fraction of dust is located inside H ii and surrounding regions. We found tight correlations between masses of cold and warm dust, again implying the same source of dust heating. Using the relation between warm and cold dust masses for estimating the total dust mass in star-forming galaxies with an accuracy better than ∼0.5 dex is proposed. On the other hand, it is shown for both samples that dust temperatures do not depend on the metallicities. The dust-to-neutral gas mass ratio strongly declines with decreasing metallicity, similar to that found in other studies of local emission-line galaxies, high-redshift gamma-ray burst hosts, and damped Ly-α absorbers. On the other hand, the dust-to-ionised gas mass ratio is about one hundred times as high implying that most of dust is located in the neutral gas. It is found that thermal free-free emission of ionised gas in compact star-forming galaxies is important in the submm and mm ranges, and it might be responsible for the submm emission excess. This effect is stronger in galaxies with lower metallicities and is also positively affected by an increased star-formation rate.

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Section: Dust-to-gas Mass Ratiosupporting

confidence: 82%

Dust emission in star-forming dwarf galaxies: General properties and the nature of the submm excess

Izotov

Гусева

Fricke

et al. 2014

A&A

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“…Converting the dust luminosity into a dust mass requires assumptions on properties such as geometry, temperature or grain size and is correspondingly uncertain. Estimates range between 10 4 to 10 6 M⊙ (Hunt et al 2005;Engelbracht et al;Vanzi et al 2008;Hirashita 2011;Remy-Ruyer et al 2013;Consiglio et al;Kepley et al 2016). What is the source of the dust?…”

Section: Discussionmentioning

confidence: 99%

Physical Properties of II Zw 40's Super Star Cluster and Nebula: New Insights and Puzzles from UV Spectroscopy

Leitherer

Byler

Lee

et al. 2018

ApJ

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We analyze far-ultraviolet spectra and ancillary data of the super star cluster SSC-N and its surrounding H II region in the nearby dwarf galaxy II Zw 40. From the ultraviolet spectrum, we derive a low internal reddening of E(B -V) = 0.07 ± 0.03, a mass of (9.1 ± 1.0)  10 5 M⊙, a bolometric luminosity of (1.1 ± 0.1)  10 9 L⊙, a number of ionizing photons of (6 ± 2)  10 52 s −1 , and an age of (2.8 ± 0.1) Myr. These parameters agree with the values derived from optical and radio data, indicating no significant obscured star formation, absorption of photons by dust, or photon leakage. SSC-N and its nebulosity are an order of magnitude more massive and luminous than 30 Doradus and its ionizing cluster. Photoionization modeling suggests a high ionization parameter and a C/O ratio where C is between primary and secondary. We calculate diagnostic emission-line ratios and compare SSC-N to local star-forming galaxies. The SSC-N nebula does not coincide with the locus defined by local galaxies. Rather, it coincides with the location of "Green Pea" galaxies, objects which are often considered nearby analogs of the galaxies reionizing the universe. Most stellar features are well-reproduced by synthetic spectra.However, the SSC-N cluster has strong, broad, stellar He II 1640 emission that cannot be reproduced, suggesting a deficit of He-enhanced stars with massive winds in the models. We discuss possible sources for the broad He II emission, including very massive stars and/or enhanced mixing processes.

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“…One of the ongoing activities of SKA-Japan is to model the radio SED based on an empirical approach using the radio-FIR relation (Takeuchi et al 2001) or based on a theoretical approach treating the evolution of H ii regions and supernova remnants in a consistent manner with the star formation history (Hirashita & Hunt 2006;Hirashita 2011). One of the results applied to the central starburst in a nearby blue compact dwarf galaxy, II Zw 40, is shown in Figure 7.…”

Section: Sed Models Of Young Starburstsmentioning

confidence: 99%

Formation, Evolution, and Revolution of Galaxies by SKA: Activities of SKA-Japan Galaxy Evolution Sub-SWG

Takeuchi¹,

Morokuma-Matsui²,

Iono³

et al. 2016

Preprint

Self Cite

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Formation and evolution of galaxies have been a central driving force in the studies of galaxies and cosmology. Recent studies provided a global picture of cosmic star formation history. However, what drives the evolution of star formation activities in galaxies has long been a matter of debate. The key factor of the star formation is the transition of hydrogen from atomic to molecular state, since the star formation is associated with the molecular phase. This transition is also strongly coupled with chemical evolution, because dust grains, i.e., tiny solid particles of heavy elements, play a critical role in molecular formation. Therefore, a comprehensive understanding of neutral-molecular gas transition, star formation and chemical enrichment is necessary to clarify the galaxy formation and evolution. Here we present the activity of SKA-JP galaxy evolution sub-science working group (subSWG) Our activity is focused on three epochs: z ∼ 0, 1, and z > 3. At z ∼ 0, we try to construct a unified picture of atomic and molecular hydrogen through nearby galaxies in terms of metallicity and other various ISM properties. Up to intermediate redshifts z ∼ 1, we explore scaling relations including gas and star formation properties, like the main sequence and the Kennicutt-Schmidt law of star forming galaxies. To connect the global studies with spatially-resolved investigations, such relations will be plausibly a viable way. For high redshift objects, the absorption lines of HI 21-cm line will be a very promising observable to explore the properties of gas in galaxies. By these studies, we will surely witness a real revolution in the studies of galaxies by SKA.

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Central free-free dominated 880-μm emission in II Zw 40

Cited by 5 publications

References 88 publications

Dust emission in star-forming dwarf galaxies: General properties and the nature of the submm excess

Dust emission in star-forming dwarf galaxies: General properties and the nature of the submm excess

Physical Properties of II Zw 40's Super Star Cluster and Nebula: New Insights and Puzzles from UV Spectroscopy

Formation, Evolution, and Revolution of Galaxies by SKA: Activities of SKA-Japan Galaxy Evolution Sub-SWG

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