| タイトル | Hubble Space Telescope Hx Imaging of Star-forming Galaxies at z approximately equal to 1-1.5: Evolution in the Size and Luminosity of Giant H II Regions |
| 本文（外部サイト） | http://hdl.handle.net/2060/20140010551 |
| 著者（英） | Arribas, S.; Smail, Ian; Swinbank, A. M.; Ebeling, H.; Crain, R. A.; Richard, J.; Rodriguez-Zaurin, J.; Rigby, J. R.; Ellis, R. S.; Colina, L.; Bower, R. G.; Livermore, R. C.; Jones, T. |
| 著者所属（英） | NASA Goddard Space Flight Center |
| 発行日 | 2013-01-28 |
| 言語 | eng |
| 内容記述 | We present Hubble Space Telescope/Wide Field Camera 3 narrow-band imaging of the H emission in a sample of eight gravitationally lensed galaxies at z = 1-1.5. The magnification caused by the foreground clusters enables us to obtain a median source plane spatial resolution of 360 pc, as well as providing magnifications in flux ranging from approximately 10 to approximately 50. This enables us to identify resolved star-forming HII regions at this epoch and therefore study their H luminosity distributions for comparisons with equivalent samples at z approximately 2 and in the local Universe. We find evolution in the both luminosity and surface brightness of HII regions with redshift. The distribution of clump properties can be quantified with an HII region luminosity function, which can be fit by a power law with an exponential break at some cut-off, and we find that the cut-off evolves with redshift. We therefore conclude that 'clumpy' galaxies are seen at high redshift because of the evolution of the cut-off mass; the galaxies themselves follow similar scaling relations to those at z = 0, but their HII regions are larger and brighter and thus appear as clumps which dominate the morphology of the galaxy. A simple theoretical argument based on gas collapsing on scales of the Jeans mass in a marginally unstable disc shows that the clumpy morphologies of high-z galaxies are driven by the competing effects of higher gas fractions causing perturbations on larger scales, partially compensated by higher epicyclic frequencies which stabilize the disc. |
| NASA分類 | Astronomy |
| レポートNO | GSFC-E-DAA-TN9658 |
| 権利 | Copyright, Distribution as joint owner in the copyright |
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