Hubble space telescope observations of accretion-induced star formation in the tadpole galaxy Kiso 5639
The tadpole galaxy Kiso 5639 has a slowly rotating disk with a drop in metallicity at its star-forming head, suggesting that star formation was triggered by the accretion of metal-poor gas. We present multi-wavelength Hubble Space Telescope Wide Field Camera 3 images of UV through I band plus Hα to...
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| Main Authors: | , , , , , , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
2016 July 13
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| In: |
The astrophysical journal
Year: 2016, Volume: 825, Issue: 2 |
| ISSN: | 1538-4357 |
| DOI: | 10.3847/0004-637X/825/2/145 |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.3847/0004-637X/825/2/145
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| Author Notes: | Debra Meloy Elmegreen, Bruce G. Elmegreen, Jorge Sánchez Almeida, Casiana Muñoz-Tuñón, Jairo Mendez-Abreu, John S. Gallagher, Marc Rafelski, Mercedes Filho, and Daniel Ceverino |
| Summary: | The tadpole galaxy Kiso 5639 has a slowly rotating disk with a drop in metallicity at its star-forming head, suggesting that star formation was triggered by the accretion of metal-poor gas. We present multi-wavelength Hubble Space Telescope Wide Field Camera 3 images of UV through I band plus Hα to search for peripheral emission and determine the properties of various regions. The head has a mass in young stars of and an ionization rate of s−1, equivalent to ∼2100 O9-type stars. There are four older star-forming regions in the tail, and an underlying disk with a photometric age of ∼1 Gyr. The mass distribution function of 61 star clusters is a power law with a slope of −1.73 ± 0.51. Fourteen young clusters in the head are more massive than , suggesting a clustering fraction of 30%-45%. Wispy filaments of Hα emission and young stars extend away from the galaxy. Shells and holes in the head H ii region could be from winds and supernovae. Gravity from the disk should limit the expansion of the H ii region, although hot gas might escape through the holes. The star formation surface density determined from Hα in the head is compared to that expected from likely pre-existing and accreted gas. Unless the surface density of the accreted gas is a factor of ∼3 or more larger than what was in the galaxy before, the star formation rate has to exceed the usual Kennicutt-Schmidt rate by a factor of . |
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| Item Description: | Gesehen am 06.05.2020 |
| Physical Description: | Online Resource |
| ISSN: | 1538-4357 |
| DOI: | 10.3847/0004-637X/825/2/145 |