Astronomy and Astrophysics – Astronomy
Scientific paper
Oct 2001
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2001newar..45..617h&link_type=abstract
New Astronomy Reviews, Volume 45, Issue 9-10, p. 617-624.
Astronomy and Astrophysics
Astronomy
3
Scientific paper
Infrared to millimeter spectral energy distributions (SEDs) have been obtained for a random sample of 17 Palomar Green quasars. The SEDs provide evidence for considerable dust emission and do not support the existence of dust-free, naked quasars. The SEDs resemble those of warm ultra-luminous infrared galaxies (ULIRGs). The variety of SED shapes suggests different heating mechanisms. While AGNs might dominate the power-law shaped and mid-infrared (MIR) peaking SEDs, the far-infrared (FIR) peaking SEDs look as though they definitely require a starburst. The mid- and far-infrared luminosities are correlated, which can be understood as follows: a turbulent environment which favours a strong starburst (showing up in the far-infrared) also likely disturbs the angular momentum of gas clouds which are then channeled inwards and feed the AGN (which heats the mid-infrared dust emission). PG quasars have blue optical colors and low extinction, but are also dust rich. Thus the dust might be distributed in a non-spherical disk/torus geometry which is seen face-on or at intermediate angles. Then from the dust mass a high edge-on optical depth is derived even in the mid-infrared. Hence, any candidate for an edge-on PG quasar will appear to us like a cool ULIRG. But not every ULIRG needs to be a dust-enshrouded quasar. Finally, when looking for a possible connection between PG quasars and other related objects, unified schemes are considered. Also, an attractive picture could be the evolutionary chain: merger of two spirals - ULIRG - radio quiet (PG) quasar - radio loud quasar - radio galaxy - elliptical.
No associations
LandOfFree
Dust in PG quasars as seen by ISO 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 Dust in PG quasars as seen by ISO, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dust in PG quasars as seen by ISO will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1006797