NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-06-19 T15:54:04 PDT
Help | Comment | NED Home

For refcode 1988A&A...206..227D:
Retrieve 94 NED objects in this reference.
Please click here for ADS abstract

NED Abstract

Copyright by European Southern Observatory (ESO). Reproduced by permission
1988A&A...206..227D The link between IRAS spectra and near-infrared emission features in external galaxies F.X. Desert and M. Dennefeld N.A.S.A.-N.R.C. Resident Research Associate, Infrared Astrophysics Branch, Laboratory for Astronomy and Solar Physics, NASA Code 685, Goddard Space Flight Center, Greenbelt, MD 20771, USA Institut d'Astrophysique de Paris, 98 bis Bld Arago, F-75014 Paris, France Received April 13, 1987; accepted April 20, 1988 Summary. The relationship in external galaxies between the presence of the near-infrared (NIR) emission features attributed to polycyclic aromatic hydrocarbon (PAH) molecules, and the far-infrared (FIR) properties as observed by IRAS, is investigated. Using the sample of galaxies spectroscopically studied in the infrared by Aitken and Roche, we find that whenever the NIR features are absent in a galaxy, the FIR spectrum displays an enhancement at shorter wavelengths (12 and 25 micron) relative to normal galaxies. This enhancement is always associated with a strong activity in the galactic nucleus. Some Seyfert galaxies do not exhibit such an infrared signature and therefore, they are probably energetically dominated by star formation processes. Finally, the importance of hard UV photons and of the hot medium in the narrow line region of active nuclei is emphasized in relation to the survival of the PAH molecules. In this frame, the absence of PAHs in the galactic centre could be taken as evidence for the presence of an active nucleus. Key words: galaxies: general, nuclei of, Seyfert-infrared radiation - X-rays: general
Retrieve 94 NED objects in this reference.
Please click here for ADS abstract

Back to NED Home