Bibcode
Kotilainen, Jari K.; Falomo, Renato; Scarpa, Riccardo
Bibliographical reference
Astronomy and Astrophysics, v.332, p.503-513 (1998)
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4
1998
Journal
Citations
50
Refereed citations
43
Description
We present the results of a high resolution (0.27'' px(-1) )
near-infrared H band (1.65 μm) imaging survey of a complete sample of
20 flat spectrum radio quasars (FSRQ) extracted from the 2Jy catalogue
of radio sources (Wall & Peacock 1985). The observed objects are
intrinsically luminous with median M(B) =3D -25.5. The median redshift
of the objects in the sample is z =3D 0.65. At this redshift, the H band
observations probe the old stellar population of the hosts at rest frame
wavelength of sim1 mum. We are able to detect the host galaxy clearly
for six (30 %) FSRQs and marginally for six (30 %) other FSRQs, while
the object remains unresolved for eight (40 %) cases. We find the
galaxies hosting FSRQs to be very luminous (M(H)sim-27). Compared with
the typical galaxy luminosity L* (M*(H)sim-25) they appear sim2 mag
brighter, although the undetected hosts may reduce this difference. They
are also at least as bright as, and probably by sim1 mag brighter than,
the brightest cluster galaxies (M(H)sim-26). The luminosities of the
FSRQ hosts are intermediate between host galaxies of low redshift
radio-loud quasars and BL Lac objects (M(H)sim-26), and the hosts of
high redshift radio-loud quasars (M(H)sim-29), in good agreement with
current unified models for radio-loud AGN, taking into account stellar
evolution in the elliptical host galaxies. Finally, we find an
indicative trend between the host and nuclear luminosity for the most
luminous FSRQs, supporting the suggestion based on studies of lower
redshift AGN, that there is a minimum host galaxy luminosity which
increases linearly with the quasar luminosity. Based on observations
collected at the European Southern Observatory, La Silla, Chile. Fig. 1b
and the appendix will be found in the on-line version at
http://link.springer.de