A giant molecular cloud catalogue in the molecular disc of the elliptical galaxy NGC 5128 (Centaurus A)
Artikel i vetenskaplig tidskrift, 2021

We present the first census of giant molecular clouds (GMCs) complete down to 106 M⊙ and within the inner 4 kpc of the nearest giant elliptical and powerful radio galaxy, Centaurus A. We identified 689 GMCs using CO(1-0) data with 1 arcsec spatial resolution (∼20 pc) and 2 km s-1 velocity resolution obtained with the Atacama Large Millimeter/submillimeter Array. The I(CO)-N(H2) conversion factor based on the virial method is XCO = (2 ± 1) × 1020 cm-2(K km s-1)-1 for the entire molecular disc, consistent with that of the discs of spiral galaxies including the Milky Way, and XCO = (5 ± 2) × 1020 cm-2(K km s-1)-1 for the circumnuclear disc (CND; within a galactocentric radius of 200 pc). We obtained the GMC mass spectrum distribution and find that the best truncated power-law fit for the whole molecular disc, with index γ≃ -2.41 ± 0.02 and upper cut-off mass $\sim \! 1.3\times 10^{7}\, \mathrm{M}_{\odot }$, is also in agreement with that of nearby disc galaxies. A trend is found in the mass spectrum index from steep to shallow as we move to inner radii. Although the GMCs are in an elliptical galaxy, the general GMC properties in the molecular disc are as in spiral galaxies. However, in the CND, large offsets in the line-width-size scaling relations (∼0.3 dex higher than those in the GMCs in the molecular disc), a different XCO factor, and the shallowest GMC mass distribution shape (γ= -1.1 ± 0.2) all suggest that there the GMCs are most strongly affected by the presence of the active galactic nucleus and/or shear motions.

Galaxies: ISM

Galaxies: elliptical and lenticular, cD

Galaxies: individual (NGC 5128)

ISM: clouds

ISM: molecules


R.E. Miura

National Astronomical Observatory of Japan

D. Espada

Universidad de Granada

SKA Organisation

A. Hirota

Atacama Large Millimeter-submillimeter Array (ALMA)

National Astronomical Observatory of Japan

C. Henkel


King Abdulaziz University

S. Verley

Universidad de Granada

Masato I. N. Kobayashi

Tohoku University

Osaka University

Satoki Matsushita

Academia Sinica

F.P. Israel

Universiteit Leiden

B. Vila-Vilaro

European Southern Observatory Santiago

Atacama Large Millimeter-submillimeter Array (ALMA)

K. Morokuma-Matsui

JAXA Institute of Space and Astronautical Science

University of Tokyo

J. Ott

National Radio Astronomy Observatory Socorro

C. Vlahakis

National Radio Astronomy Observatory

A. Peck

Gemini Observatory North

Susanne Aalto

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

M. Hogerheijde

Universiteit Leiden

Universiteit Van Amsterdam

N. Neumayer


D. Iono

The Graduate University for Advanced Studies (SOKENDAI)

National Astronomical Observatory of Japan

K. Kohno

Research Center for the Early Universe

University of Tokyo

H. Takemura

National Astronomical Observatory of Japan

The Graduate University for Advanced Studies (SOKENDAI)

S. Komugi

Kogakuin University of Technology and Engineering

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 504 4 6198-6215


Subatomär fysik

Meteorologi och atmosfärforskning

Astronomi, astrofysik och kosmologi



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