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Paper text:
the relationship between seyfert galaxies and radio - loud galaxies has not been explored in detail .
however , a complete sample of flat - spectrum radio - loud agn contains a significant fraction of seyfert - like sources , including one which would be classified as a narrow - line seyfert 1 ( nls1 ) .    to understand the physical mechanisms responsible for producing the different characteristics of agn
, a multiwavelength approach is needed .
correlations between properties at different wavelengths can be used to reject and refine physical models of the central regions of agn .
the parkes half - jansky flat - spectrum sample ( phfs ) @xcite is interesting in this context because it is a radio - selected sample .
the selection criteria are as follows :    * radio - loud : 2.7ghz flux @xmath0 0.5 jy . *
flat - spectrum : @xmath1 , where @xmath2 * galactic latitude : @xmath3b@xmath4 * @xmath5 dec(b1950 )
@xmath6    this sample contains 323 sources with a wide range of properties which can be quite different to agn selected by optical colours .
the phfs agn have a large range in optical luminosities , with more than 50 objects having absolute magnitudes in the seyfert luminosity range ( m@xmath7 - 23 ) .
another interesting characteristic is the large dispersion in optical colours of this sample compared with optically selected samples such as the large bright quasar survey @xcite .
the mechanism responsible for producing the large dispersion in optical colours , especially the significant number of red sources in the sample , is not at all well established .
there have been suggestions of dust reddening @xcite , reddening due to the underlying galaxy spectrum @xcite and synchrotron reddening @xcite .
we consider two questions :    1 .
are the reddened continuum colours associated with changes in the emission lines of the agn ? 2 .
can we identify the reddening mechanisms contributing to each agn ?
we have low resolution optical spectra of an unbiased subsample of the phfs .
this subsample was divided into three equal colour bins based on the b - k colours of the objects : blue ( b - k @xmath8 3 ) , intermediate ( 3 @xmath8 b - k @xmath8 4.4 ) and red ( b - k @xmath0 4.4 ) .
a composite spectrum of the objects in each bin was made ( see @xcite for a description of the technique used ) .
the results are plotted in figure 1 .
it should be noted that the continuum has been normalised to the same slope for each bin to compare the emission line properties over the range of colours .
the lbqs composite spectrum is also shown as a comparison with an optically selected sample @xcite .
there are clear differences between the different composites .
the width of h@xmath9 line decreases as redness increases and o(3727 ) is only seen in the red composite .
the mg(2800 ) line is also quite broad in the blue and intermediate composites , and much narrower in the red composite .
further analysis of the spectra in the red bin shows there are two different types of spectra in this bin : ( 1 ) low redshift galaxy - type spectra , and ( 2 ) higher redshift quasar spectra .
several very red objects in the parkes sample seem to appear red owing to a large contribution from a galactic component .
the 4000  break in the spectrum of the galactic light reduces the amount of light in the blue filter giving a b - k colour which is quite red .
these objects are at low redshifts and are generally resolved .
masci @xcite has fitted an evolved elliptical galaxy sed to the phfs spectra , showing that these objects have a high proportion of galactic light in their spectra .
these objects also have the steepest radio spectrum with values of @xmath10 .
the composite spectrum of these resolved sources is fairly typical of a galaxy with no h@xmath9 emission .
the second group of red objects in the sample are higher redshift quasar / seyfert - type objects .
they show the strong emission lines characteristic of quasars and have flatter radio spectral indices . whiting et al .
@xcite have modelled the reddening by synchrotron emission using broad band seds .
they show that these objects tend to have a strong component of synchrotron emission which is responsible for their red continuum .
these quasars would be missed in a traditional blue - selected quasar sample .
the composite of these unresolved sources has a completely different shape , with narrow permitted emission lines at civ(1549 ) , ciii](1909 ) and mgii(2798 ) superimposed on a fairly smooth continuum .
thus it appears that the red agn have relatively narrow emission lines .
a fuller description of these results will appear in oshlack et al .
in examining the spectra from the parkes sample we have identified a nls1 candidate , pks 2004 - 447 ( figure 2 ) .
one model for nls1s suggests they are agn oriented towards us , so that the doppler broadening of a disk - like broad line region would naturally produce narrower emission lines @xcite .
an extremely radio - loud nls1 could provide an independent test of such physical models of nls1s , and agn unification in general .
a low resolution spectrum of this source shows an h@xmath9 width of @xmath112000 km  s@xmath12 .
there is some indication of fe emission on the blueward side of h@xmath9 and the source has been detected at x - ray energies @xcite .
this object is extremely radio - loud with a radio to optical flux ratio ( r ) exceeding 7000 .
the colour of pks 2004 - 447 is very red , in contrast with the previously discovered radio - loud nls1 , rgb j0044 + 193 which was quite blue @xcite .
the radio spectrum of pks 2004 - 447 is also quite steep , with recent measurements of the ( contemporaneous ) radio spectral index giving @xmath13 , consistent with radio indices of radio - quiet nls1s ( moran , these proceedings ) . a higher resolution spectrum of pks 2004 - 447 will be obtained , to confirm its identity .
a complete flat - spectrum radio - loud sample of agn includes a significant fraction of seyfert - like agn including a nls1 . 
 analysis of their optical spectra suggests that the reddest continuum colours are either associated with agn in nearby resolved galaxies , or distant quasars showing relatively narrow permitted emission lines .    ,    ,    ,    ,    ,    galaxies : active ; quasars : general ; quasars : radio - loud