The Reddest Quasars
Comparison of some of the red quasars identified in our
2MASS/FIRST sample (filled circles) with 540 FBQS objects detected in
2MASS (plus signs are radio-loud, diamonds radio-quiet). The red
objects contain both radio-loud and quiet objects and have 0.7 < z <
2.6. These red quasars are roughly two magnitudes below the FBQS limit
of R=17.8 (right panel), but an IR-selected survey to K=15.5 would
have found all of them (left panel). The two brightest red quasars in
K are gravitationally lensed and appear in 2MASS because of
magnification bias, hinting at a larger red population lurking below
the 2MASS limits. These plots demonstrate that even a radio-selected
sample such as FBQS, because of its reliance on optical material to
select targets, overlooks what may be an important and sizable portion
of the quasar population.
albrecht@physics.ucdavis.edu