Publications of the Astronomical Society of Australia Publications of the Astronomical Society of Australia Society
Publications of the Astronomical Society of Australia
RESEARCH ARTICLE

Resolving the Nucleus of Centaurus A at Mid-Infrared Wavelengths

Leonard Burtscher A B E , Klaus Meisenheimer A , Walter Jaffe C , Konrad R. W. Tristram D and Huub J. A. Röttgering C
+ Author Affiliations
- Author Affiliations

A Max Planck Institute for Astronomy, Heidelberg, Germany

B Fellow of the International Max Planck Research School (IMPRS) for Astronomy and Cosmic Physics, Heidelberg, Germany

C Max Planck Institute for Radio Astronomy, Bonn, Germany

D Sterrewacht Leiden, Leiden University, Leiden, The Netherlands

E Corresponding author. Email: burtscher@mpia.de

Publications of the Astronomical Society of Australia 27(4) 490-495 https://doi.org/10.1071/AS09068
Submitted: 3 10 2009  Accepted: 4 8 2010   Published: 13 October 2010

Abstract

We have observed Centaurus A with the Mid-Infrared Interferometric Instrument (MIDI) at the Very Large Telescope Interferometer at resolutions of 7–15 mas (at 12.5 μm) and filled gaps in the (u,v) coverage in comparison to earlier measurements. We are now able to describe the nuclear emission in terms of geometric components and derive their parameters by fitting models to the interferometric data. With simple geometrical models, the best fit is achieved for an elongated disk with flat intensity profile with diameter 76 ± 9 × 35 ± 2 mas (1.41 ± 0.17 × 0.65 ± 0.03 pc) whose major axis is oriented at a position angle (PA) of 10.1 ± 2.2° east of north. A point source contributes 47 ± 11% of the nuclear emission at 12.5 μm. There is also evidence that neither such a uniform nor a Gaussian disk are good fits to the data. This indicates that we are resolving more complicated small-scale structure in active galactic nuclei with MIDI, as has been seen in Seyfert galaxies previously observed with MIDI. The PA and inferred inclination i = 62.6–2.6 +2.1° of the dust emission are compared with observations of gas and dust at larger scales.

Keywords: techniques: high angular resolution — galaxies: active


Acknowledgments

This research is based on observations collected at the European Southern Observatory, Chile, program number 081.B-0121 and has made use of the Jean-Marie Mariotti Center LITpro service codevelopped by CRAL, LAOG, and FIZEAU. The authors wish to thank the anonymous referee for advice in improving the paper. L.B. wishes to thank Roy van Boekel, Jörg-Uwe Pott, Christian Leipski, René Andrae, and Hans-Walter Rix for helpful discussions.


References


Antonucci, R. 1993, ARA&A, 31, 473 open url image1

Berger, J. P., &  Segransan, D. 2007, New Astronomy Review, 51, 576
CrossRef | open url image1

Burtscher, L., Jaffe, W., &  Raban, D., et al. 2009, ApJL, 705, L53
CrossRef | open url image1

Cohen, M., Walker, R. G., &  Carter, B., et al. 1999, AJ, 117, 1864
CrossRef | open url image1

Espada, D., Matsushita, S., &  Peck, A., et al. 2009, ApJ, 695, 116
CrossRef | open url image1

Hardcastle, M. J., Worrall, D. M., &  Kraft, R. P., et al. 2003, ApJ, 593, 169
CrossRef | open url image1

Jaffe, W., Meisenheimer, K., &  Röttgering, H. J. A., et al. 2004, Nature, 429, 47
CrossRef | open url image1

Jaffe, W. J. 2004, in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, Vol. 5491, Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, Ed. Traub, W. A., 715 open url image1

Kraft, R. P., Forman, W., &  Jones, C., et al. 2000, ApJL, 531, L9
CrossRef | open url image1

Leinert, C., Graser, U., &  Przygodda, F., et al. 2003, ApSS, 286, 73 open url image1

Meisenheimer, K., Tristram, K. R. W., &  Jaffe, W., et al. 2007, A&A, 471, 453
CrossRef | open url image1

Neumayer, N., Cappellari, M., &  Reunanen, J., et al. 2007, ApJ, 671, 1329
CrossRef | open url image1

Quillen, A. C., Bland-Hawthorn, J., &  Green, J. D., et al. 2008, MNRAS, 384, 1469
CrossRef | open url image1

Raban, D., Jaffe, W., Röttgering, H., Meisenheimer, K., &  Tristram, K. R. W. 2009, MNRAS, 394, 1325
CrossRef | open url image1

Schartmann, M., Meisenheimer, K., &  Klahr, H., et al. 2009, MNRAS, 393, 759
CrossRef | open url image1

Tallon-Bosc, I., Tallon, M., &  Thiébaut, E., et al. 2008, in Presented at the Society of Photo-Optical Instrumentation Engineers (SPIE) Conference, Vol. 7013, Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, open url image1

Tingay, S. J., Jauncey, D. L., &  Reynolds, J. E., et al. 1998, AJ, 115, 960
CrossRef | open url image1

Tingay, S. J., Preston, R. A., &  Jauncey, D. L. 2001, AJ, 122, 1697
CrossRef | open url image1

Tristram, K. R. W. 2007, PhD thesis, Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany, open url image1

Tristram, K. R. W., Meisenheimer, K., &  Jaffe, W., et al. 2007, A&A, 474, 837
CrossRef | open url image1

Tristram, K. R. W., Raban, D., &  Meisenheimer, K., et al. 2009, A&A, 502, 67
CrossRef | open url image1

Urry, C. M., &  Padovani, P. 1995, PASP, 107, 803
CrossRef | open url image1









1 Applying Rayleigh’s criterion to an interferometer leads to a resolution of λ/2BL. However, given sufficient S/N, one can already distinguish models at lower resolutions, in our case at ~λ/3BL.

2 The nightly build from 2010 February 7 was used. It can be downloaded from http://www.strw.leidenuniv.nl/~koehler/MIA+EWS-daily-snapshot.html.

3 The online version of LITpro can be found at http://www.jmmc.fr/litpro_page.htm.

Export Citation

View Altmetrics