Star Formation Efficiencies at Giant Molecular Cloud Scales in the Molecular Disk of the Elliptical Galaxy NGC 5128 (Centaurus A)
Artikel i vetenskaplig tidskrift, 2019

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 (similar to 1 '', or 18 pc), including information from large to small spatial scales and total flux. We find a total molecular gas mass of 1.6 x 10(9) M-circle dot and 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 similar to 1 M-circle dot 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 a scale of several kiloparsecs 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 active galactic nucleus feedback. The higher SFEs in the outer disk suggest that only central molecular gas or filaments with sufficient density and strong shear motions will remain in similar to 1 Gyr, which will later result in the compact molecular distributions and low SFEs usually seen in other giant ellipticals with cold gas.

galaxies: star formation

galaxies: nuclei

ISM: molecules

galaxies: elliptical and lenticular, cD

galaxies: individual (NGC 5128)


D. Espada

National Astronomical Observatory of Japan

The Graduate University for Advanced Studies (SOKENDAI)

S. Verley

Universidad de Granada

R. E. Miura

National Astronomical Observatory of Japan

F. P. Israel

Universiteit Leiden

C. Henkel


King Abdulaziz University

S. Matsushita

Academia Sinica

B. Vila-Vilaro

European Southern Observatory Santiago

Atacama Large Millimeter-submillimeter Array (ALMA)

J. Ott

National Radio Astronomy Observatory Socorro

K. Morokuma-Matsui

University of Tokyo

Japan Aerospace Exploration Agency

A. B. Peck

Gemini Observatory North

A. Hirota

National Astronomical Observatory of Japan

Atacama Large Millimeter-submillimeter Array (ALMA)

Susanne Aalto

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik

A. C. Quillen

University of Rochester

M. R. Hogerheijde

Universiteit Leiden

Universiteit Van Amsterdam

N. Neumayer


C. Vlahakis

National Radio Astronomy Observatory

D. Iono

The Graduate University for Advanced Studies (SOKENDAI)

National Astronomical Observatory of Japan

K. Kohno

University of Tokyo

Astrophysical Journal

0004-637X (ISSN) 1538-4357 (eISSN)

Vol. 887 1 88


Astronomi, astrofysik och kosmologi

Annan geovetenskap och miljövetenskap

Multidisciplinär geovetenskap


Onsala rymdobservatorium



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