Star Formation Efficiencies at Giant Molecular Cloud Scales in the Molecular Disk of the Elliptical Galaxy NGC 5128 (Centaurus A)
| Autor: | Satoki Matsushita, Frank P. Israel, Akihiko Hirota, Alison B. Peck, Catherine Vlahakis, Kana Morokuma-Matsui, Christian Henkel, Susanne Aalto, Michiel R. Hogerheijde, Simon Verley, Juergen Ott, Alice C. Quillen, Nadine Neumayer, Kotaro Kohno, Daisuke Iono, Daniel Espada, Rie E. Miura, B. Vila-Vilaro |
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| Přispěvatelé: | Low Energy Astrophysics (API, FNWI) |
| Rok vydání: | 2019 |
| Předmět: |
Physics
Spiral galaxy 010504 meteorology & atmospheric sciences Radio galaxy Star formation Molecular cloud Centaurus A FOS: Physical sciences Astronomy and Astrophysics Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics - Astrophysics of Galaxies 01 natural sciences Galaxy Dust lane Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) 0103 physical sciences Elliptical galaxy Astrophysics::Solar and Stellar Astrophysics Astrophysics::Earth and Planetary Astrophysics 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics 0105 earth and related environmental sciences |
| Zdroj: | Astrophysical Journal, 887(1):88. IOP Publishing Ltd. Astrophysical Journal (0004-637X), 887(1), 88 |
| ISSN: | 0004-637X |
| DOI: | 10.48550/arxiv.1906.01237 |
| Popis: | We present ALMA CO(1-0) observations toward the dust lane of the nearest elliptical and radio galaxy, NGC 5128 (Centaurus A), with high angular resolution ($\sim$ 1 arcsec, or 18 pc), including information from large to small spatial scales and total flux. We find a total molecular gas mass of 1.6$\times$10$^9$ $M_\odot$ and we reveal the presence of filamentary components more extended than previously seen, up to a radius of 4 kpc. We find that the global star formation rate is $\sim$1 \Msol yr$^{-1}$, which yields a star formation efficiency (SFE) of 0.6 Gyr$^{-1}$ (depletion time $\tau =$1.5 Gyr), similar to those in disk galaxies. We show the most detailed view to date (40\,pc resolution) of the relation between molecular gas and star formation within the stellar component of an elliptical galaxy, from several kpc scale to the circumnuclear region close to the powerful radio jet. Although on average the SFEs are similar to those of spiral galaxies, the circumnuclear disk (CND) presents SFEs of 0.3 Gyr$^{-1}$, lower by a factor of 4 than the outer disk. The low SFE in the CND is in contrast to the high SFEs found in the literature for the circumnuclear regions of some nearby disk galaxies with nuclear activity, probably as a result of larger shear motions and longer AGN feedback. The higher SFEs in the outer disk suggests that only central molecular gas or filaments with sufficient density and strong shear motions will remain in $\sim$1 Gyr, which will later result in the compact molecular distributions and low SFEs usually seen in other giant ellipticals with cold gas. Comment: Minor update. 20 pages, 11 figures, accepted for publication in ApJ |
| Databáze: | OpenAIRE |
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