Uncovering the kiloparsec-scale stellar ring of NGC 5128

Author(s)
J. T. Kainulainen, J. F. Alves, Y. Beletsky, J. Ascenso, J. M. Kainulainen, A. Amorim, J. Lima, R. Marques, A. Moitinho, J. Pinhão, J. Rebordão, F. D. Santos
Abstract

We reveal the stellar light emerging from the kiloparsec-scale,ring-like structure of the NGC 5128 (Centaurus A) galaxy in unprecedented detail. We use arcsecond-scale resolution near infrared images to create a “dust-free” view of the central region of the galaxy, which we then use to quantify the shape of the revealed structure. At the resolution of the data, the structure contains several hundreds of discreet, point-like or slightly elongated sources. The typical extinction-corrected surface brightness of the structure is KS ≈ 16.5 mag/arcsec^2, and we estimate the total near-infrared luminosity of the structure to be M ≈ -21 mag. We use diffraction limited (FWHM resolution of ≈0.1'', or 1.6 pc) near-infrared data taken with the NACO instrument on the VLT to show that the structure decomposes into thousands of separate, mostly point-like sources. According to the tentative photometry, the most luminous sources have MK ≈ -12 mag, making them red supergiants or relatively low-mass star clusters. We also discuss the large-scale geometry implied by the reddening signatures of dust in our near-infrared images.Based on observations made with ESO Telescopes at the La Silla or Paranal Observatories under programme IDs 066.C-0310 and 081.C-0477Figure [see full text see full text] is only available in electronic format www.aanda.org

Organisation(s)
Department of Astrophysics
External organisation(s)
Harvard-Smithsonian Center for Astrophysics, Universidade de Coimbra, University of Helsinki, Aalto University, European Southern Observatory (Chile), Universidade Técnica de Lisboa, National Institute of Engineering, Technology and Innovation (INETI)
Journal
Astronomy & Astrophysics
Volume
502
Pages
L5-L8
ISSN
0004-6361
DOI
https://doi.org/10.1051/0004-6361/200912624
Publication date
08-2009
Peer reviewed
Yes
Austrian Fields of Science 2012
103004 Astrophysics
Keywords
Portal url
https://ucrisportal.univie.ac.at/en/publications/bafcd24f-57f1-4455-a80a-5e3306455afa