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A Survey of X-ray–Emitting IRAS Galaxies: A New Class of Objects or Hidden AGNs?

Published online by Cambridge University Press:  12 April 2016

M. Dennefeld
M. Dennefeld*
Affiliation:
Institat d’Astrophysique, 98 bis Bd. Arago, F-75014 Paris, France

Extract

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A cross-correlation between the IRAS PSC and the ROSAT All-Sky Survey has provided 242 sources detected in both surveys (Boiler et al. 1992). About half of these have redshifts in the literature and a spectral classification. An unexpected result was the discovery of many galaxies with X-ray luminosities up to a few 1043 ergs s−1, yet without Seyfert characteristics in their optical spectra (e.g., Boiler et al. 1993). To investigate this problem further and evaluate the frequency of occurrence of these peculiar objects, a spectroscopic follow-up has been undertaken to:

  1. • Determine velocities and luminosities for all the unclassified objects.

  2. • Reevaluate the classification of high X-ray luminosity objects previously not recognized as Seyferts. In particular, spectral resolution or coverage and variability are important parameters to consider if one wants to detect faint signs of Seyfert activity.

Type
IX. Surveys and Properties of Active Galaxies and Related Sources
Information
International Astronomical Union Colloquium , Volume 159: Emission Lines in Active Galaxies: New Methods and Techniques , 1997 , pp. 421 - 422
Copyright
Copyright © Astronomical Society of the Pacific 1997

References

Boller, Th., et al. 1992, A&A, 261, 57.Google Scholar
Boller, Th., et al. 1993, in ‘First Light in the Universe’, Ed. Frontieres, , p. 339.Google Scholar