Hostname: page-component-848d4c4894-xfwgj Total loading time: 0 Render date: 2024-07-07T16:57:26.486Z Has data issue: false hasContentIssue false

Mid-IR Properties of Seyferts: Spitzer IRS Spectroscopy of the IRAS 12 μm Seyfert Sample

Published online by Cambridge University Press:  03 June 2010

Vassilis Charmandaris
Affiliation:
University of Crete, Department of Physics, GR-71003, Heraklion, Greece Email: vassilis@physics.uoc.gr IESL/Foundation for Research and Technology - Hellas, GR-71110, Heraklion, Greece, and Chercheur Associé, Observatoire de Paris, F-75014, Paris, France
Yanling Wu
Affiliation:
Infrared Processing and Analysis Center, Caltech, Pasadena, CA 91125, USA
Jiasheng Huang
Affiliation:
Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA
Luigi Spinoglio
Affiliation:
Istituto di Fisica dello Spazio Interplanetario, INAF, I-00133 Rome, Italy Dipartimento di Fisica, Universita di Roma, La Sapienza, Rome, Italy
Silvia Tommasin
Affiliation:
Istituto di Fisica dello Spazio Interplanetario, INAF, I-00133 Rome, Italy Dipartimento di Fisica, Universita di Roma, La Sapienza, Rome, Italy
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We performed an analysis of the mid-infrared properties of the 12 μm Seyfert sample, a complete unbiased 12 μm flux limited sample of local Seyfert galaxies selected from the IRAS Faint Source Catalog based on low-resolution spectra obtained with the Infrared Spectrograph (IRS) on-board Spitzer Space Telescope. A detailed presentation of this analysis is discussed by Wu et al. (2009). We find that, on average, the 15–30 μm slope of the continuum is 〈 α15–30〉 = −0.85 ± 0.61 for Seyfert 1s and −1.53 ± 0.84 for Seyfert 2s, and there is substantial scatter in each type. Moreover, nearly 32% of Seyfert 1s, and 9% of Seyfert 2s, display a peak in the mid-infrared spectrum at 20 μm, which is attributed to an additional hot dust component. The polycyclic aromatic hydrocarbon (PAH) equivalent width decreases with increasing dust temperature, as indicated by the global infrared color of the host galaxies. However, no statistical difference in PAH equivalent width is detected between the two Seyfert types of the same bolometric luminosity. Finally, we propose a new method to estimate the AGN contribution to the integrated 12 μm galaxy emission, by subtracting the “star formation” component in the Seyfert galaxies, making use of the tight correlation between PAH 11.2 μm luminosity and 12 μm luminosity for star forming galaxies.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2010

References

Antonucci, R. R. J. & Miller, J. S. 1985, ApJ, 297, 621CrossRefGoogle Scholar
Antonucci, R. 1993, ARAA, 31, 473CrossRefGoogle Scholar
Bernard-Salas, J., et al. 2009, ApJS, 184, 230CrossRefGoogle Scholar
Brandl, B. R., et al. 2006, ApJ, 653, 1129CrossRefGoogle Scholar
Buchanan, C. L., et al. 2006, AJ, 132, 401CrossRefGoogle Scholar
Clavel, J., et al. 2000, A&A, 357, 839Google Scholar
Deo, R. P., et al. 2007, ApJ, 671, 124CrossRefGoogle Scholar
Draine, B. T. 2003, ARAA, 41, 241CrossRefGoogle Scholar
Draine, B. T. & Li, A. 2001, ApJ, 551, 807CrossRefGoogle Scholar
Elitzur, M. 2008, New Astron. Revs., 52, 274CrossRefGoogle Scholar
Förster Schreiber, N. M., Roussel, H., Sauvage, M., & Charmandaris, V. 2004, A&A, 419, 501Google Scholar
Gorjian, V., Cleary, K., Werner, M. W., & Lawrence, C. R. 2007, ApJ, 655, L73CrossRefGoogle Scholar
Hao, L., et al. 2007, ApJ, 655, L77CrossRefGoogle Scholar
Hao, L., et al. 2009, ApJ, 704, 1159CrossRefGoogle Scholar
Ho, L. C. 2008, ARAA, 46, 475CrossRefGoogle Scholar
Houck, J. R., et al. 2004, ApJS, 154, 18CrossRefGoogle Scholar
Nenkova, M., Sirocky, M. M., Nikutta, R., Ivezić, Ž., & Elitzur, M. 2008, ApJ, 685, 160CrossRefGoogle Scholar
Rush, B., Malkan, M. A., & Spinoglio, L. 1993, ApJ Sup, 89, 1Google Scholar
Smith, J. D. T., et al. 2007a, ApJ, 656, 770CrossRefGoogle Scholar
Smith, J. D. T., et al. , 2007b, PASP, 119, 1133CrossRefGoogle Scholar
Spinoglio, L. & Malkan, M. A. 1989, ApJ, 342, 83CrossRefGoogle Scholar
Sturm, E., et al. 2006, ApJ, 653, L13CrossRefGoogle Scholar
Thompson, G. D., Levenson, N. A., Uddin, S. A., & Sirocky, M. M. 2009, ApJ, 697, 182CrossRefGoogle Scholar
Tommasin, S., et al. 2008, ApJ, 676, 836CrossRefGoogle Scholar
Tommasin, S., et al. 2009, in preparationGoogle Scholar
Urry, C. M. & Padovani, P. 1995, PASP, 107, 803CrossRefGoogle Scholar
Verma, A., Charmandaris, V., Klaas, U., Lutz, D., & Haas, M. 2005, Space Sci. Revs., 119, 355CrossRefGoogle Scholar
Weedman, D. W., et al. 2005, ApJ, 633, 706CrossRefGoogle Scholar
Werner, M. W., et al. 2004, ApJS, 154, 1CrossRefGoogle Scholar
Wu, Y., Charmandaris, V., Huang, J., Spinoglio, L., & Tommasin, S. 2009, ApJ, 701, 658CrossRefGoogle Scholar