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  • 1
    Online Resource
    Online Resource
    The ISM of Low Metallicity Galaxies: The Herschel view
    Cambridge University Press (CUP) ; 2012
    In:  Proceedings of the International Astronomical Union Vol. 8, No. S292 ( 2012-08), p. 127-134
    Details
    In: Proceedings of the International Astronomical Union, Cambridge University Press (CUP), Vol. 8, No. S292 ( 2012-08), p. 127-134
    Abstract: The wide variety of low metallicity galaxies of the local universe serve as convenient laboratories to study the evolution of gas and dust and conditions for star formation in environments which may resemble those of the early universe. The Herschel Dwarf Galaxy Survey is studying the far infrared (FIR) and submillimeter (submm) properties of the gas and dust in galaxies with metallicity values as low as 1/45 that of solar. With complementary Spitzer , Laboca/APEX, Scuba/JCMT data, the dust spectral energy distributions are well constrained now, providing more accurate dust masses. We find a steep drop in dust-to-gas mass ratio (D/G) when the metallicity is below 12+log(O/H) ∼ 8. A submillimeter excess can be found in some low metallicity galaxies, which, when present, becomes apparent at wavelengths at or longer than 500 μm. While CO is difficult to observe in low metallicity gas, the FIR fine structure lines, on the other hand, are very luminous and highlight a potentially important reservoir of CO-free molecular gas, better traced by the 158 μm [CII] line.
    Type of Medium: Online Resource
    ISSN: 1743-9213 , 1743-9221
    URL: Article
    DOI: 10.1017/S1743921313000781
    Language: English
    Publisher: Cambridge University Press (CUP)
    Publication Date: 2012
    detail.hit.zdb_id: 2170724-8
    SSG: 16,12
    Location Call Number Limitation Availability
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    Online Resource
  • 2
    Online Resource
    Online Resource
    Low Metallicity ISM: excess submillimetre emission and CO-free H 2 gas
    Cambridge University Press (CUP) ; 2011
    In:  Proceedings of the International Astronomical Union Vol. 7, No. S284 ( 2011-09), p. 141-148
    Details
    In: Proceedings of the International Astronomical Union, Cambridge University Press (CUP), Vol. 7, No. S284 ( 2011-09), p. 141-148
    Abstract: The low metallicity interstellar medium of dwarf galaxies gives a different picture in the far infrared(FIR)/submillimetre(submm)wavelengths than the more metal-rich galaxies. Excess emission is often found in the submm beginning at or beyond 500 μm. Even without taking this excess emission into account as a possible dust component, higher dust-to-gas mass ratios (DGR) are often observed compared to that expected from their metallicity for moderately metal-poor galaxies. The Spectral Energy Distributions (SEDs) of the lowest metallicity galaxies, however, give very low dust masses and excessively low values of DGR, inconsistent with the amount of metals expected to be captured into dust if we presume the usual linear relationship holding for all metallicities, including the more metal-rich galaxies. This transition seems to appear near metalllicities of 12 + log(O/H) 8.0 - 8.2. These results rely on accurately quantifying the total molecular gas reservoir, which is uncertain in low metallicity galaxies due to the difficulty in detecting CO(1-0) emission. Dwarf galaxies show an exceptionally high [CII] 158 μm/CO (1-0) ratio which may be indicative of a significant reservoir of ‘CO-free’ molecular gas residing in the photodissociated envelope, and not traced by the small CO cores.
    Type of Medium: Online Resource
    ISSN: 1743-9213 , 1743-9221
    URL: Article
    DOI: 10.1017/S1743921312008939
    Language: English
    Publisher: Cambridge University Press (CUP)
    Publication Date: 2011
    detail.hit.zdb_id: 2170724-8
    SSG: 16,12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
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