AN INFRARED CENSUS OF DUST IN NEARBY GALAXIES WITH SPITZER (DUSTINGS). IV. DISCOVERY OF HIGH-REDSHIFT AGB ANALOGS
| Autor: | Albert A. Zijlstra, Olivia Jones, Margaret Meixner, G. Sonneborn, Evan D. Skillman, Gregory C. Sloan, N. Britavskiy, Patricia A. Whitelock, Martha L. Boyer, Robert D. Gehrz, Iain McDonald, J. Th. van Loon, Alceste Z. Bonanos, Kristen B. W. McQuinn, Atefeh Javadi, Martin Groenewegen |
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| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Physics
010308 nuclear & particles physics Infrared Metallicity Theoretical models FOS: Physical sciences Astronomy and Astrophysics Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics 01 natural sciences Redshift Galaxy Stars Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science QB460 0103 physical sciences Asymptotic giant branch Astrophysics::Solar and Stellar Astrophysics Astrophysics::Earth and Planetary Astrophysics 010303 astronomy & astrophysics Solar and Stellar Astrophysics (astro-ph.SR) Astrophysics::Galaxy Astrophysics Dwarf galaxy |
| Zdroj: | Boyer, M L, {McQuinn}, K B W, Groenewegen, M A T, Zijlstra, A, Whitelock, P A, Van Loon, J T, {Sonneborn}, G, Sloan, G C, Skillman, E D, Meixner, M, Mcdonald, I, Jones, O, Javadi, A, Gehrz, R D, Britavskiy, N & {Bonanos}, A Z 2017, ' AN INFRARED CENSUS OF DUST IN NEARBY GALAXIES WITH SPITZER (DUSTINGS). IV. DISCOVERY OF HIGH-REDSHIFT AGB ANALOGS ', The Astrophysical Journal . https://doi.org/10.3847/1538-4357/aa9892 The Astrophysical Journal |
| ISSN: | 0004-637X 1538-3881 0037-8720 0067-0049 1538-3873 0004-6361 |
| DOI: | 10.3847/1538-4357/aa9892 |
| Popis: | The survey for DUST in Nearby Galaxies with Spitzer (DUSTiNGS) identified several candidate Asymptotic Giant Branch (AGB) stars in nearby dwarf galaxies and showed that dust can form even in very metal-poor systems (Z ~ 0.008 $Z_\odot$). Here, we present a follow-up survey with WFC3/IR on the Hubble Space Telescope (HST), using filters that are capable of distinguishing carbon-rich (C-type) stars from oxygen-rich (M-type) stars: F127M, F139M, and F153M. We include six star-forming DUSTiNGS galaxies (NGC 147, IC 10, Pegasus dIrr, Sextans B, Sextans A, and Sag DIG), all more metal-poor than the Magellanic Clouds and spanning 1 dex in metallicity. We double the number of dusty AGB stars known in these galaxies and find that most are carbon rich. We also find 26 dusty M-type stars, mostly in IC 10. Given the large dust excess and tight spatial distribution of these M-type stars, they are most likely on the upper end of the AGB mass range (stars undergoing Hot Bottom Burning). Theoretical models do not predict significant dust production in metal-poor M-type stars, but we see evidence for dust excess around M-type stars even in the most metal-poor galaxies in our sample (12+log(O/H) = 7.26-7.50). The low metallicities and inferred high stellar masses (up to ~10 $M_\odot$) suggest that AGB stars can produce dust very early in the evolution of galaxies (~30 Myr after they form), and may contribute significantly to the dust reservoirs seen in high-redshift galaxies. 18 pages, 9 figures, accepted for publication in ApJ |
| Databáze: | OpenAIRE |
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