A multi-wavelength continuum characterization of high-redshift broad
  absorption line quasars
  We present the results of a multi-wavelength study of a sample of
high-redshift Radio Loud (RL) Broad Absorption Line (BAL) quasars. This way we
extend to higher redshift previous studies on the radio properties, and
broadband optical colors of these objects. We have se- lected a sample of 22 RL
BAL quasars with 3.6 z 4.8 cross-correlating the FIRST radio survey with the
SDSS. Flux densities between 1.25 and 9.5 GHz have been collected with the JVLA
and Effelsberg-100m telescopes for 15 BAL and 14 non-BAL quasars used as
compar- ison sample. We determine the synchrotron peak frequency, constraining
their age. A large number of GigaHertz Peaked Spectrum (GPS) and High Frequency
Peakers (HFP) sources has been found in both samples (80% for BAL and 71% for
non-BAL QSOs), not suggesting a younger age for BAL quasars. The spectral index
distribution provides information about the orientation of these sources, and
we find statistically similar distributions for the BAL and non-BAL quasars in
contrast to work done on lower redshift samples. Our sample may be too small to
convincingly find the same effect, or might represent a real evolutionary
effect based on the large fraction of young sources. We also study the
properties of broadband colors in both optical (SDSS) and near- and
mid-infrared (UKIDSS and WISE) bands, finding that also at high redshift BAL
quasars tend to be optically redder than non-BAL quasars. However, these
differences are no more evident at longer wavelength, when comparing colors of
the two samples by mean of the WISE survey.
