Volume 371, Number 2, May IV 2001
|Page(s)||527 - 537|
|Section||Cosmology (including clusters of galaxies)|
|Published online||15 May 2001|
An X-ray selected sample of radio-loud quasars
Osservatorio Astronomico di Brera, via Brera 28, 20121 Milano, Italy e-mail: email@example.com
2 S. I. S. S. A., via Beirut 2-4, 34014 Trieste, Italy e-mail: firstname.lastname@example.org
Corresponding author: A. Wolter, email@example.com
Accepted: 16 March 2001
We construct the first X-ray selected sample of broad line radio-loud AGN from the EMSS survey. In order to test unifying schemes for radio-loud objects, their spectral and statistical properties (both flat and steep spectrum objects) are examined and compared with those of other samples of blazars. The X-ray selection allows us to explore properties of radio-loud quasars 10-100 weaker in the radio band than classical samples. The most convincing interpretation of our results is that there are no radio-loud quasars whose synchrotron emission peak reaches the EUV-soft X-ray band at these (radio) flux levels. Moreover, due to the comparatively weak non-thermal emission, a quasi-thermal component appears to contribute at optical-UV energies. The detection of sources at low radio fluxes also reveals a large population of steep spectrum quasars and the lack of the predicted turnover in the quasar (radio) counts. The evolution of X-ray selected radio-loud quasars does not significantly differ from that of radio-selected ones, and flat spectrum and steep spectrum sources appear to behave quite similarly.
Key words: galaxies: active / galaxies: evolution / galaxies: luminosity function / quasars: general / radio continuum: galaxies / X-rays: galaxies
© ESO, 2001
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.