Open AccessThe space density of low‐redshift active galactic nuclei
Author(s) -
Londish D.,
Boyle B. J.,
Schade D. J.
Publication year - 2000
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2000.03734.x
Subject(s) - physics , astrophysics , redshift , luminosity function , qsos , active galactic nucleus , extrapolation , luminosity , power law , spitzer space telescope , astronomy , galaxy , telescope , mathematical analysis , statistics , mathematics
We present a new determination of the optical luminosity function (OLF) of active galactic nuclei (AGN) at low redshifts ( z <0.15) based on Hubble Space Telescope ( HST ) observations of X‐ray‐selected AGN. The HST observations have allowed us to derive a true nuclear luminosity function for these AGN. The resulting OLF illustrates a two power‐law form similar to that derived for quasi‐stellar objects (QSOs) at higher redshifts. At bright magnitudes, M B <−20, the OLF derived here exhibits good agreement with that derived from the Hamburg/European Southern Observatory (ESO) QSO survey. However, the single power‐law form for the OLF derived from the Hamburg/ESO survey is strongly ruled out by our data at M B >−20. Although the estimate of the OLF is best fitted by a power‐law slope at M B <−20.5 that is flatter than the slope of the OLF derived at z >0.35, the binned estimate of the low‐redshift OLF is still consistent with an extrapolation of the z >0.35 OLF based on pure luminosity evolution.