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- W2095502601 abstract "We present mid-infrared imaging and far-infrared (FIR) spectroscopy of five IBm galaxies observed by ISO as part of our larger study of the interstellar medium of galaxies. Most of the irregulars in our sample are very actively forming stars, and one is a starburst system. Thus, most are not typical Im galaxies. The mid-infrared imaging was in a band centered at 6.75 μm that is dominated by polycyclic aromatic hydrocarbons (PAHs) and in a band centered at 15 μm that is dominated by small dust grains. The spectroscopy of three of the galaxies includes [C II] λ158 μm and [O I] λ63 μm, important coolants of photodissociation regions (PDRs), and [O III] λ88 μm and [N II] λ122 μm, which come from ionized gas. [O I] λ145 μm and [O III] λ52 μm were measured in one galaxy as well. These data are combined with PDR and H II region models to deduce properties of the interstellar medium of these galaxies. We find a decrease in PAH emission in our irregulars relative to small grain, FIR, and Hα emissions for increasing FIR color temperature, which we interpret as an increase in the radiation field due to star formation resulting in a decrease in PAH emission. The f15/fHα ratio is constant for our irregulars, and we suggest that the 15 μm emission in these irregulars is being generated by the transient heating of small dust grains by single-photon events, possibly Lyα photons trapped in H II regions. The low f15/fHα ratio, as well as the high f/f15 ratio, in our irregulars compared to spirals may be due to the lower overall dust content, resulting in fewer dust grains being, on average, near heating sources. We find that, as in spirals, a large fraction of the [C II] emission comes from PDRs. This is partly a consequence of the high average stellar effective temperatures in these irregulars. However, our irregulars have high [C II] emission relative to FIR, PAH, and small grain emission compared to spirals. If the PAHs that produce the 6.75 μm emission and the PAHs that heat the PDR are the same, then the much higher f/f6.75 ratio in irregulars would require that the PAHs in irregulars produce several times more heat than the PAHs in spirals. Alternatively, the carrier of the 6.75 μm feature tracks, but contributes only a part of, the PDR heating, that is due mostly to small grains or other PAHs. In that case, our irregulars would have a higher proportion of the PAHs that heat the PDRs compared to the PAHs that produce the 6.75 μm feature. The high f/f ratio may indicate a smaller solid angle of optically thick PDRs outside the H II regions compared to spirals. The very high L/LCO ratios among our sample of irregulars could be accounted for by a very thick [C II] shell around a tiny CO core in irregulars, and PDR models for one galaxy are consistent with this. The average densities of the PDRs and far-ultraviolet stellar radiation fields hitting the PDRs are much higher in two of our irregulars than in most normal spirals; the third irregular has properties like those in typical spirals. We deduce the presence of several molecular clouds in each galaxy with masses much larger than typical GMCs." @default.
- W2095502601 created "2016-06-24" @default.
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- W2095502601 date "2001-05-20" @default.
- W2095502601 modified "2023-10-14" @default.
- W2095502601 title "The Interstellar Medium of Star‐forming Irregular Galaxies: The View with<i>ISO</i>" @default.
- W2095502601 cites W1514115692 @default.
- W2095502601 cites W1598393877 @default.
- W2095502601 cites W1623182580 @default.
- W2095502601 cites W1665493422 @default.
- W2095502601 cites W1919063799 @default.
- W2095502601 cites W1969747332 @default.
- W2095502601 cites W1970360781 @default.
- W2095502601 cites W1970704351 @default.
- W2095502601 cites W1977521416 @default.
- W2095502601 cites W1980741350 @default.
- W2095502601 cites W1981918493 @default.
- W2095502601 cites W1986104751 @default.
- W2095502601 cites W1987342590 @default.
- W2095502601 cites W1988894843 @default.
- W2095502601 cites W1996689021 @default.
- W2095502601 cites W1998981512 @default.
- W2095502601 cites W2000672249 @default.
- W2095502601 cites W2002315459 @default.
- W2095502601 cites W2004710535 @default.
- W2095502601 cites W2004959618 @default.
- W2095502601 cites W2005107898 @default.
- W2095502601 cites W2006618843 @default.
- W2095502601 cites W2007918469 @default.
- W2095502601 cites W2014173500 @default.
- W2095502601 cites W2015295900 @default.
- W2095502601 cites W2016052786 @default.
- W2095502601 cites W2016313662 @default.
- W2095502601 cites W2019842583 @default.
- W2095502601 cites W2021635986 @default.
- W2095502601 cites W2023699986 @default.
- W2095502601 cites W2031074223 @default.
- W2095502601 cites W2033343088 @default.
- W2095502601 cites W2034304789 @default.
- W2095502601 cites W2034432536 @default.
- W2095502601 cites W2035530018 @default.
- W2095502601 cites W2035603111 @default.
- W2095502601 cites W2038403623 @default.
- W2095502601 cites W2038688917 @default.
- W2095502601 cites W2040096756 @default.
- W2095502601 cites W2042240341 @default.
- W2095502601 cites W2043311965 @default.
- W2095502601 cites W2043993818 @default.
- W2095502601 cites W2044794357 @default.
- W2095502601 cites W2045355272 @default.
- W2095502601 cites W2047022405 @default.
- W2095502601 cites W2047461465 @default.
- W2095502601 cites W2047862113 @default.
- W2095502601 cites W2048705526 @default.
- W2095502601 cites W2051817124 @default.
- W2095502601 cites W2054167874 @default.
- W2095502601 cites W2056057868 @default.
- W2095502601 cites W2057136268 @default.
- W2095502601 cites W2058269171 @default.
- W2095502601 cites W2068175193 @default.
- W2095502601 cites W2069655807 @default.
- W2095502601 cites W2074161500 @default.
- W2095502601 cites W2076007067 @default.
- W2095502601 cites W2077396405 @default.
- W2095502601 cites W2079788987 @default.
- W2095502601 cites W2080005391 @default.
- W2095502601 cites W2080680869 @default.
- W2095502601 cites W2081115376 @default.
- W2095502601 cites W2082487757 @default.
- W2095502601 cites W2085713960 @default.
- W2095502601 cites W2087621424 @default.
- W2095502601 cites W2088779624 @default.
- W2095502601 cites W2090424522 @default.
- W2095502601 cites W2091733180 @default.
- W2095502601 cites W2092004593 @default.
- W2095502601 cites W2093334306 @default.
- W2095502601 cites W2093906672 @default.
- W2095502601 cites W2107833181 @default.
- W2095502601 cites W2113448636 @default.
- W2095502601 cites W2132160265 @default.
- W2095502601 cites W2137388102 @default.
- W2095502601 cites W2145321334 @default.
- W2095502601 cites W2167635287 @default.
- W2095502601 cites W2269158622 @default.
- W2095502601 cites W3035852092 @default.
- W2095502601 cites W3043732792 @default.
- W2095502601 cites W3098388870 @default.
- W2095502601 cites W3099778302 @default.