Physics
Scientific paper
Sep 2004
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004sptz.prop.3349s&link_type=abstract
Spitzer Proposal ID #3349
Physics
Scientific paper
We have recently shown that the FIR dust luminosity is similar for powerful FR2 radio galaxies and steep spectrum quasars. This finding is based on photometry with the ISO satellite of 105 sources of the 3CR catalog. Our results support the unified schemes in which the FR2 galaxies are quasars viewed at high inclination so that their nuclei are hidden behind a dust torus which intercepts the optical-ultraviolet AGN radiation and reemits it in the infrared. Interestingly, for most of the FR2 galaxies, the MIR/FIR luminosity ratio is considerably lower than for the quasars. So either the FR2 galaxies are intrinsically different, contrary to the unification theory, or the dust torus, if seen edge-on as presumed in the FR2 galaxies, is optically thick even at MIR wavelengths leading to a suppressed MIR continuum. We here propose to address this issue by MIR spectroscopy looking for the 9.7 and 18 micron silicate absorption features which should show up in the FR2 galaxies, and for AGN-typical high excitation MIR emission lines (like Ne[V] 14.3, 24.3 micron and O[IV] 25.9 micron). As the FIR emission may be powered not only by the AGN but additionally by a starburst, we also search for PAH bands (at 6.2, 7.7, 8.6, 11.3 and 12.7 micron) because their presence or absence provide clues on the hardness of the engine's spectrum and thus on the nature of the activity. We have selected a well balanced sample of 10 FR2 galaxies and 10 quasars from the 3CR catalogue with redshifts between z=0.05 and z=1.5. The sample members display luminous to hyperluminous dust emission as revealed by ISO. Only Spitzer's IRS is capable of obtaining sensitive low resolution (R~64-128) MIR spectra between 5 and 40 micron. The analysis of the requested observations will make a significant contribution to the debate about unification and the role which starbursts play in the powerful 3CR sources.
Haas Martin Dr.
Krugel Endrik Dr.
Schulz Bernhard Dr.
Siebenmorgen Ralf
No associations
LandOfFree
IRS spectroscopy of 3CR radio galaxies and quasars: Probing the unified schemes and the starburst contribution. does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with IRS spectroscopy of 3CR radio galaxies and quasars: Probing the unified schemes and the starburst contribution., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and IRS spectroscopy of 3CR radio galaxies and quasars: Probing the unified schemes and the starburst contribution. will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1823979